J Shoulder Elbow Surg (2015) -, 1-8
www.elsevier.com/locate/ymse
The effect of proximal humeral bone loss on revision reverse total shoulder arthroplasty Scott P. Stephens, MDa,*, Kevin C. Paisley, DOb, M. Russell Giveans, PhDc, Michael A. Wirth, MDd a
Fondren Orthopedic Group, Houston, TX, USA University of Texas Health Science Center at San Antonio, San Antonio, TX, USA c Elite Research Institute, Minneapolis, MN, USA d Professor/Charles A. Rockwood, Jr., MD Chair, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA b
Background: Revision shoulder arthroplasty can be complicated by osseous and soft tissue deficiencies. Proximal humeral bone loss can result in diminished implant stability and reduced functional outcomes, and some studies have advocated the use of humeral allograft in this setting. This study compares the outcomes of revision reverse total shoulder arthroplasty (RTSA) in patients both with and without proximal humeral bone loss. Methods: During a 6-year period, 32 patients were revised to RTSA for failed shoulder hemiarthroplasty. Proximal humeral bone loss was found in 16 patients, with an average loss of 36.3 mm (range, 17.266 mm). Patients were followed up an average of 51.2 months with the American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, visual analog scale score for pain, subjective outcome ratings, and radiographs. Results: Significant improvement was found for average American Shoulder and Elbow Surgeons score (30.7 to 66.8), Simple Shoulder Test score (1.6 to 5.3), visual analog scale score (6.0 to 2.6), and forward flexion (51 to 100 ) but not for external rotation (15 to 19.1 ). No difference was demonstrated for functional or subjective outcomes compared with patients with intact humeral bone, except for active motion. On radiographic examination, 3 patients demonstrated humeral-sided loosening. Five complications were noted in patients with humeral bone loss. Conclusion: Revision RTSA can provide successful outcomes in the presence of proximal humeral bone loss without the use of allograft. Implant stability may be improved by the use of a cemented long-stem monoblock humeral prosthesis in revision settings. Level of evidence: Level III, Retrospective Cohort Design, Treatment Study. Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Proximal humeral bone loss; revision reverse total shoulder arthroplasty; failed shoulder arthroplasty; allograft-prosthesis composite
Institutional Review Board approval was provided by the University of Texas Health Science Center: No. HSC20010109H. *Reprint requests: Scott P. Stephens, MD, Fondren Orthopedic Group, 3100 Post Oak Blvd #551, Houston, TX 77056, USA. E-mail address: [email protected] (S.P. Stephens).
The prevalence of shoulder arthroplasty has continued to increase in the past decade, and projected estimations reveal a growth rate that exceeds lower extremity joint replacement.13,18 The increased number of shoulder
1058-2746/$ - see front matter Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. http://dx.doi.org/10.1016/j.jse.2015.02.020
2 replacements, though, will result in a proportional burden of revision cases. Shoulder arthroplasty can fail from either osseous or soft tissue deficiencies and result in pain, instability, hardware failure, infections, or loss of function.15,22,24,27 Failure can result from either a single cause or, as in a majority of patients, a combination of factors.4,16,17,33 This makes revision shoulder arthroplasty technically demanding, and it is demonstrated by reported outcomes to be inferior to primary shoulder arthroplasty.1,8,19,30,31 Identifying the cause of reconstruction failure can potentially optimize outcomes after revision surgery.26 Dines et al15 performed an outcomes analysis of shoulder arthroplasty and found that results could be predicted on the basis of the indication for the revision procedure, with soft tissue deficiencies producing inferior results. One potential factor that can affect preoperative planning for revision cases is proximal humeral osseous deficiency.12,20,21,33 Proximal humeral bone loss can result from prior surgeries, infection, or complex proximal humerus fractures in which the tuberosities progress to nonunion, malunion, or resorption.5 The loss of humeral bone stock can affect component fixation as well as disrupt the insertion of rotator cuff muscles.12,14 Reverse total shoulder arthroplasty (RTSA) has been effective in treating failed shoulder arthroplasty with soft tissue or bone loss because of its increased constraint and diminished reliance on an intact rotator cuff.3,20,23,31 This implant, though, relies on a preserved humeral bone stock for implant fixation, rotational stability, and soft tissue attachments to improve function and stability postoperatively.10,12,28,32 The loss of proximal humeral bone and associated soft tissue structures can thus play a pivotal role in a patient’s results and has led some to advocate the use of allograft-prosthesis composites.10,20 The goal of this study was to compare the outcomes for revision RTSA with and without proximal humeral bone loss. In addition, we compare the results of revision reverse shoulder arthroplasty in the setting of proximal humeral bone loss without the use of allograft to current literature.
Materials and methods This study was a retrospective case series of prospectively collected data. During a 6-year period from 2004 to 2010, 34 patients (22 women, 12 men) with a mean age of 70 years (range, 53-87 years) were treated for failed shoulder arthroplasty with a single-stage conversion to a reverse shoulder prosthesis (Delta Extend; DePuy, Warsaw, IN, USA). The study was part of an Institutional Review Board–approved prospective database collection, and all enrolled patients provided informed consent for the follow-up examinations and use of their data. Two patients without proximal humeral bone loss were lost to follow-up; attempts were made to contact them, but they were unable to be reached, leaving 32 patients in the study. The initial diagnosis for implantation of the 32 hemiarthroplasties was either a proximal
S.P. Stephens et al. humerus fracture (11) or rotator cuff tear arthropathy (21). Failure of the arthroplasty resulted from pain, progressing glenoid arthrosis, diminished function, or instability. All patients failed to respond to attempted conservative treatment consisting of physical therapy and activity modification. All revision procedures were performed by the senior author (M.A.W.). Patients were followed up clinically and radiographically for an average of 51 months (range, 24-130 months). Proximal humeral bone loss was identified in 50% (16 of 32) of the revision RTSAs, with the initial diagnosis consisting of proximal humerus fracture in 10 patients and rotator cuff tear arthropathy in 6 patients. The inclusion criteria for the study included any failed shoulder arthroplasty with pain or limited function that had failed nonoperative management, a functioning deltoid, and minimum 2year follow-up. Exclusion criteria were a nonfunctioning deltoid, infection, and inability to complete 2 years of follow-up.
Clinical assessment Patients were evaluated clinically with the use of the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST) score, and visual analog scale (VAS) score for pain. Scales for rating subjective outcomes were used to determine if there was sensation of instability, pain with active motion, and pain at rest. Range of motion was measured for forward flexion, external rotation, and internal rotation. Internal rotation was determined by the most proximal spinal level that the patient could reach.
Radiographic assessment All patients were evaluated with radiographs consisting of anteroposterior, scapular Y, internal and external Grashey, and axillary views. Preoperative radiographs were evaluated for instability, glenoid bone loss, glenoid arthrosis, proximal humeral bone loss, position of humeral head, and condition of the tuberosities. Glenohumeral subluxation was evaluated with regard to direction and the amount of translation of the center of the prosthetic head relative to the center of the glenoid, as described by Rispoli et al.25 Glenoid bone loss was determined by the use of the intraoperative classification by Antu~ na.2 Proximal humeral bone loss was calculated on postoperative radiographs by the method described by Budge et al.7 The condition of the tuberosities was evaluated for presence of malunion, nonunion, or resorption. Postoperative radiographs were evaluated for humeral loosening by the classification of Gruen et al16 adapted to the shoulder and classified according to width (2 mm). Loosening was defined as displacement of the humeral component between the time of the initial postoperative radiograph and the most recent follow-up or if radiolucency >2 mm was present in more than 3 zones. The glenoid component was assessed for the presence of scapular notching according to the Sirveaux-Nerot grading system.29 Any radiolucent lines around the glenoid screws, central peg, or baseplate were classified according to their width (2 mm). Loosening was considered to be present if the glenoid component had migrated, as demonstrated by shift, tilt, or subsidence, or if complete radiolucency >2 mm was present in each zone. Instability was classified as present or absent. Acromial fractures and locations were noted to involve either the acromion body or scapular spine. Heterotopic bone located on the inferior glenoid was identified and recorded.
Humeral bone loss and reverse arthroplasty
3
Surgical technique
Results
Patients were evaluated preoperatively for the possibility of subclinical infection with the use of complete blood count, C-reactive protein level, and erythrocyte sedimentation rate. The operative technique consisted of positioning the patient in a semi-Fowler position with the head secured and the arm draped free. All patients were given general anesthesia in addition to an intrascalene block. A deltopectoral approach was used for all patients and incorporation of pre-existing incisions. The upper border of the pectoralis major tendon was released to assist in exposure, and the subdeltoid and subacromial spaces were carefully freed of scar tissue. The tuberosities were evaluated, and if present, an attempt was made to reattach them to preserve posterior rotator cuff function and proximal bone stock. A subscapularis peel, if present, was performed and tagged for reattachment to improve postoperative stability. Extraction of the humeral prosthesis was performed with a combination of flexible osteotomes, high-speed bur, and implant extraction device. A humeral osteotomy was necessary in 12 patients to retrieve the humeral stem, and a fibular strut graft was applied to reinforce the native bone stock in 2 of these patients. In 1 patient, the posterior rotator cuff muscles were transferred to the remaining greater tuberosity. Intraoperative frozen section analysis was obtained to evaluate for >5 polymorphonuclear neutrophils per high-power field, and cultures were held for 2 weeks. After removal of the humeral implant, cement was removed only when necessary for component insertion. A complete capsular release surrounding the glenoid was performed as well as removal of heterotopic ossification to prevent soft tissue or bone impingement on the implant. Depending on the proximal bone stock, metaphyseal reaming was performed, and a trial implant was placed. The implant was reduced and evaluated for stability and gapping between the polyethylene and glenosphere in extension and external rotation and with adduction and internal rotation. The humeral component’s height was determined by soft tissue tension and stability of the prosthesis. If proximal bone loss was encountered, a fracture jig was applied to maintain the humeral component’s height and version. Monoblock humeral components were used in 10 of the patients with proximal bone loss, and modular components were used in the other 6 patients. Cement was used for fixation of the humeral component in all patients with proximal humeral bone loss. The overall operative time for patients with bone loss was found to be 37 minutes longer than for patients without bone loss. Postoperatively, the patient was placed in a sling, and motion was restricted to hand and elbow movement for the first month. After 4 weeks, gentle active and active assisted activities were begun. Strengthening was delayed until 3 months. Physical therapy was based on a home-directed stretching and strengthening program.
Overall, a significant improvement was noted in clinical outcomes after revision to RTSA in all 32 patients with increase in SST score (1.5 to 6.2; P < .001), ASES score (29.7 to 70.6; P < .001), and VAS score (6.4 to 1.9; P < .001). Range of motion also significantly improved in forward flexion (51 to 118 ; P < .001) and external rotation (15 to 27 ; P < .001). In the 16 patients undergoing revision RTSA with proximal humeral bone loss, a significant improvement in SST score (1.6 to 5.3; P < .001), VAS score (5.4 to 3.1; P ¼ .020), ASES score (30.7 to 66.8; P < .001), and forward flexion (52 to 100 ; P < .001) was demonstrated. There was not a significant improvement in external rotation (15 to 19.1 ; P ¼ .383). Significant improvements were also seen in the 16 patients who had intact proximal humeral bone stock for SST score (1.4 to 7.1; P < .001), VAS score (P < .001), ASES score (P < .001), forward flexion (52 to 135 ; P < .001), and external rotation (17 to 34 ; P ¼ .012). In comparing the group with bone loss to the intact proximal humerus group, there was no statistical difference in preoperative clinical assessment for SST score (1.6 vs. 1.4; P ¼ .953), VAS score (6.0 vs. 6.7; P ¼ .396), ASES score (30.7 vs. 28.8; P ¼ .703), forward flexion (51 vs. 52 ; P ¼ .926), or external rotation (15 vs. 17 ; P ¼ .727). Postoperatively, patients with proximal humeral bone loss had lower functional outcome scores and pain scores, but no statistical difference was found for ASES score (66.8 vs.74.4; P ¼ .503), SST score (5.3 vs. 7.1; P < .445), and VAS score (2.6 vs. 1.2; P ¼ .057). A significant difference, though, was found for postoperative range of motion, with the bone loss group having less forward flexion (100 vs. 135 ; P ¼ .022) and external rotation (19 vs. 34 ; P ¼ .009) (Table I). Preoperative radiographs revealed severe instability in 9 patients, moderate instability in 7 patients, mild instability in 13 patients, and no instability in the remaining patients. Glenoid erosion was severe in 6, moderate in 7, mild in 13, and none in 6. No difference in instability or glenoid erosion was found between the 2 groups. In the patients with proximal humeral bone loss, postoperative radiographs demonstrated an average proximal humeral bone loss of 36.3 mm (range, 17.2-66 mm). Glenoid notching was found in 27 patients, with grade 3 or 4 notching found in 5 patients with humeral bone loss and in only 2 patients without. No metaglene loosening was noted in either group. Humeral loosening was identified in 3 patients with proximal humeral bone loss, with 2 patients demonstrating stem subsidence (Fig. 1). No patients without humeral bone loss demonstrated humeral stem loosening. Nine patients had inferior glenoid heterotopic ossification in the bone loss group compared with 6 in the non–bone loss group. Complications occurred in 31% (5 of 16) of the patients with proximal humeral bone loss. One patient
Statistical analyses All variables were analyzed for normality by the Shapiro-Wilk test. Independent samples t tests and Mann-Whitney U tests were used to determine differences between groups, where appropriate. Paired samples t test and Wilcoxon tests were used to determine differences within groups from preoperative to postoperative, where appropriate. Statistical analyses were performed with SPSS v.21 (SPSS, Inc., Chicago, IL, USA). Significance was set at P < .05.
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S.P. Stephens et al. Table I Clinical outcomes of revision RTSA with and without proximal humeral bone loss Variable
Age BMI Preoperative SST VAS1 VAS2 VAS3 VAS4 FF ER ASES Postoperative SST VAS1 VAS2 VAS3 VAS4 FF ER ASES Change SST VAS1 VAS2 VAS3 VAS4 FF ER ASES
Proximal humeral bone loss
Proximal humeral bone intact
P value
70.5 25.7
70.3 29.5
.953 .196
1.6 5.4 6.0 8.0 4.2 51.3 15.0 30.7
1.4 3.9 6.7 9.1 3.8 51.6 16.9 28.8
.642 .197 .396 .069 .7 .926 .727 .703
5.3 3.1 2.6 4.2 1.1 100.0 19.1 66.8
7.1 1.4 1.2 2.9 0.7 135.3 34.1 74.4
.133 .108 .057 .24 .477 .022 .009 .25
3.7 2.4 3.5 3.8 3.1 48.8 4.1 36.1
5.6 2.6 5.6 6.2 3.1 83.8 17.2 45.6
.113 .866 .138 .073 .752 .069 .092 .445
RTSA, reverse total shoulder arthroplasty; ASES, American Shoulder and Elbow Surgeons; SST, Simple Shoulder Test; VAS, visual analog scale; BMI, body mass index; ER, external rotation; FF, forward flexion.
sustained an intraoperative fracture of the proximal humerus during humeral stem removal. The fracture and osteotomy site were stabilized with a cerclage cable; the patient’s postoperative recovery was unaffected, and a successful outcome was achieved. Another patient sustained a postoperative periprosthetic humeral shaft fracture just distal to the tip of the prosthesis. The patient was treated conservatively and went on to a varus malunion. The patient had poor results (forward flexion of 30 , external rotation of 4 , ASES score of 63, and VAS score of 4). Another patient developed a hematoma that resulted in a temporary nerve palsy in the radial and median nerve distribution but resolved spontaneously within the first week. One patient sustained a dislocation 1 year after conversion to RTSA and had repeated instability after closed reduction necessitating a return to the operating room for placement of a spacer and increased polyethylene size. The patient had a successful
Figure 1 (A) Hemiarthroplasty with tuberosity resorption and proximal humeral bone loss that was revised to a reverse total shoulder with standard-length humeral component. (B) Distal migration of humeral stem from implant loosening despite the use of cement.
outcome and no more instability until he fell nearly 10 years later, resulting in a periprosthetic fracture that disrupted the humeral stem fixation. The patient was taken to the operating room for open reduction and internal fixation of the fracture. The patient had 6.6 cm of proximal humeral bone loss, and the intraoperative decision was made to apply a proximal humeral allograft composite to restore proximal bone loss and to allow
Humeral bone loss and reverse arthroplasty
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Figure 2 (A) Patient with revision RTSA and severe proximal humeral bone loss who sustained a periprosthetic fracture and implant loosening. (B) Postoperative revision film demonstrating revised RTSA and humeral allograft placement and restoration of bone stock. (C and D) Final postoperative films demonstrate dislocated prosthesis. Scapular notching to the level of the inferior screw is also noted.
reimplantation of the humeral stem. The humeral stem was grossly loose at the time of surgery, and remaining proximal humeral bone was osteopenic. The allograft was prepared in a step-cut manner to optimize biomechanics of allograft to host bone stability and stabilized with an AO plate consisting of cerclage wires and multiple screws. The implant was cemented into the humeral allograft and the deltoid repaired to the allograft and remaining humeral bone. Two weeks after the surgery, radiographs revealed an atraumatic anteriorly dislocated prosthesis. The patient was taken back to the operating
room, and a 9-mm polyethylene with 9-mm spacer was implanted. Excellent soft tissue tension and stability were noted during range of motion, but at the 6-week followup, the patient was noted to have redislocated. No additional surgical management was performed (Fig. 2). Another patient was noted to have an acromion fracture that involved the scapular spine and was managed conservatively with a good outcome (forward flexion, 130 ; external rotation, 30 ; VAS score, 1.6). Only 1 complication was noted in the non–bone loss group and consisted of an acromion fracture. The patient was
6 managed conservatively and had a good outcome (ASES score, 95; forward flexion, 125 ; VAS score, 1).
Discussion Proximal humeral bone loss in the setting of revision shoulder arthroplasty can significantly affect humeral implant fixation and restoration of humeral length and disrupt soft tissue attachments and deltoid tensioning.6,10-12 Overall, we demonstrated significant improvement in all patients after revision surgery. No difference was found for postoperative functional or subjective outcomes scores in patients with proximal humeral bone loss compared with patients with intact humeral bone. Budge et al7 reviewed 15 patients revised to RTSA for failed arthroplasty with a comparable amount of average proximal humeral bone loss (38.4 vs. 36.3 mm) to our study. We found similar clinical outcomes for ASES score (68 vs. 67) and forward flexion (103 vs. 100 ), and although their final external rotation was less than ours, they did demonstrate greater overall improvement. This illustrates that consistent successful functional outcomes can be obtained after revision RTSA in patients with bone loss. We did find a significant difference in the final range of motion for patients with proximal humeral bone loss compared with patients without bone loss. Although reverse total shoulder implants have not been as successful in restoring external rotation compared with forward flexion, the loss of external rotator attachments may explain why patients with bone loss improved on average only by 4 of external rotation compared with 17 for patients with intact greater tuberosities.28 This was also shown by Budge et al,7 who found that although external rotation did improve, it was not found to be significant, and improvement of external rotation lag sign was seen in only 4 of 10 patients. Although other authors have recommended the removal of tuberosities to eliminate a source of impingement that may lead to dislocation,9 we prefer to attempt repair of the tuberosities, if they are present, to increase bone stock and attempt to restore the rotator cuff tension and function. Restoration of anatomic tuberosity position can also assist in re-establishing deltoid tension. If the tuberosity is not able to be restored to its anatomic location, consideration should be given to latissimus dorsi transfer at the time of revision surgery in an attempt to gain active external rotation. The loss of proximal humeral bone can also disrupt the deltoid attachment, specifically the anterior deltoid, and could explain the difference found in forward flexion. The effect of proximal humeral bone loss on humeral implant fixation was studied by Cuff et al,12 who biomechanically compared the stability of humeral stems with a bone loss construct. They demonstrated increased rotational micromotion in the bone loss group as well as more documented component failures. All 5 of their implant failures consisted of modular component prostheses.
S.P. Stephens et al. Boileau et al6 reported on 37 patients undergoing revision RTSA surgery and found that humeral component complications represented 21% of revision surgeries and were the second most common reason to revise an RTSA. They noted that humeral bone loss was >30 mm in all 10 cases of humeral loosening and implant derotation. We found that 19% (3 of 16) of the patients in the bone loss group had humeral implant loosening, with 2 of these stems demonstrating implant subsidence. These 3 patients had between 2.1 and 3.8 cm of humeral bone loss. The humeral migration significantly affected the patient’s results, with poor functional outcomes, pain scores, and range of motion (patient 1: ASES score of 31.6, external rotation of 0 , VAS score of 7; patient 2: ASES score of 43, external rotation of 5 , VAS score of 5.4). Although these patients did not require a return to the operating room, the distal migration may have resulted in alteration of humeral length and subsequent changes in soft tissue tension as well as discomfort from implant instability. All 3 of these patients had standard-length humeral components, and we would recommend long-stem humeral components for all revision procedures to improve implant fixation. Although 6 of our patients had modular components, we did not have any implant dissociations but agree that a monoblock component would prevent increased stress on the modular metaphyseal humeral components. This was also demonstrated by Boileau et al6 in their series, in which 5 patients with component separation required a revision to a monoblock stem, and by Budge et al,7 whose only component fracture occurred in a patient with a modular prosthesis that was unsupported by metaphyseal bone. Recent reports have advocated the use of an allograftprosthetic composite in the setting of proximal humeral bone loss to restore bone stock, to increase implant fixation, to allow reattachment of the subscapularis, to maintain prosthesis height, and to improve the mechanical advantage of the deltoid by providing lateral offset.10,20 Levy et al20 reviewed 29 patients who underwent revision to RTSA after failed hemiarthroplasty for fracture, of which 8 patients were managed with an allograft reverse shoulder prosthesis. All functional scores, except forward flexion, showed trends of increased improvement in patients treated with an allograft-prosthesis construct, and 75% (6 of 8) rated their results good or excellent compared with 48% (10 of 21) treated with prosthesis alone. Chacon et al10 performed a follow-up study of 25 patients with an average bone loss of 53.6 mm that used an allograft-prosthesis composite. They demonstrated improvements similar to those of our study in functional outcomes (ASES score, 69 vs. 67; SST score, 4.5 vs. 5.3) and active motion (forward flexion, 50 vs. 49 ). On radiographic examination, 2 patients had graft resorption, 2 had graft fragmentation, and 4 others had no incorporation at the allograft-host junction. Budge et al,7 in their study of humeral bone loss, did not advocate the use of a proximal humeral allograft because long humeral stems and the semiconstrained nature of the
Humeral bone loss and reverse arthroplasty prosthesis can provide implant stability, and the soft tissue surrounding the proximal humerus was no longer present in their patients. Our results were similar to those of Budge et al and demonstrate that similar functional outcomes can be obtained with a reverse prosthesis alone and that humeral length, implant height, and deltoid tension can be restored with the proper use of a fracture jig, cement, and an attempt to restore the greater tuberosity to its anatomic position. Although we obtained outcomes similar to those reported by Chacon et al,10 their cohort did have an increased average bone loss as seen in our study, and the exact amount of bone loss that may benefit from augmentation of proximal humeral bone stock to improve implant fixation, stability, and deltoid tensioning is still unknown. Complications were found in 31% (5 of 16) of the patients with proximal humeral bone loss compared with only 1 patient in the intact humeral bone stock group. We found that the complication rate for patients undergoing revision without proximal humeral bone loss was encouraging, and although more complications were found in patients with bone loss, only 1 patient required a return to the operating room as the result of a periprosthetic fracture after a fall. We had only 1 patient with postoperative instability and no component failures. These results were similar to those of Budge et al,7 who reported that 47% (7 of 15) of the patients with bone loss had complications, but only 2 required a return to the operating room. This is in comparison to Chacon et al,10 who noted 5 patients with complications, including 2 patients who required a return to the operating room. One patient required a revision allograft placement after falling and fracturing the allograft and polyethylene component; postoperatively, the patient had recurrent instability that resulted in another revision to a larger glenosphere to gain stability. Another patient required removal of the allograft because of infection within a few weeks after the revision surgery. This is consistent with problems associated with allograft placement reported in the literature involving graft resorption, nonunion, and failure.20 We did identify scapular notching in 88% (14 of 16) of the patients with proximal humeral bone loss, including 5 patients with severe notching, compared with none in the study by Chacon et al.10 This may be the result of the Grammont-style prosthesis used in this study that has an increased neck-shaft angle, and longer follow-up will be needed to determine whether this results in metaglene loosening. The present study had several limitations. The study involved a tertiary referral center with an experienced shoulder surgeon, and these results may not translate to other practices. Second, although the data were collected prospectively, they were reviewed retrospectively and subject to this inherent limitation. This study would have been strengthened by an equal number of patients who had allograft-prosthesis composite placement to directly compare outcomes. This study, though, is strengthened by the high percentage of patient retention as well as by the long clinical and radiographic follow-up duration.
7
Conclusion Revision shoulder arthroplasty in the setting of proximal humeral bone loss offers many technical challenges to the surgeon, but our results demonstrate that successful outcomes can be obtained with the use of a reverse shoulder prosthesis. Although significantly less active motion was found in patients with proximal humeral bone loss, no difference was found for functional and subjective outcome scores compared with patients without bone loss in a revision setting. Overall, all functional variables increased in patients with proximal humeral bone loss except for external rotation. A higher incidence of humeral stem loosening, though, was found in patients with proximal humeral bone loss, and subsidence was demonstrated with the use of a standardlength prosthesis. Although allograft can successfully restore proximal humeral bone stock and potentially improve implant fixation that may be required in some cases, we think that equivalent clinical and radiographic results can be obtained without the use of an allograftprosthesis composite and its associated technical difficulty. Our results support the use of a long-stem monoblock prosthesis to diminish humeral-sided component failure and that consideration should also be given to tendon transfers to improve active external rotation at the time of revision surgery if a preoperative deficit is present. This study illustrates that successful outcomes can be obtained in revision reverse shoulder arthroplasty in the presence of proximal humeral bone loss and that further studies will be needed to determine the proper use of allograft in this setting.
Disclaimer The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
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S.P. Stephens et al. Orthop Relat Res 2011;469:2531-7. http://dx.doi.org/10.1007/s11999010-1685-x Bigliani K, Flatow E, McCluskey G, Fischer RA. Failed prosthetic replacement for displaced proximal humerus fractures. Orthop Trans 1991;15:747-8. Boileau P, Krishan SG, Tinsi L, Walch G, Coste JS, Mole D. Tuberosity malposition and migration: reasons for poor outcomes after hemiarthroplasty for displaced fractures of the proximal humerus. J Shoulder Elbow Surg 2002;11:401-12. http://dx.doi.org/10.1067/mse. 2002.124527 Boileau P, Watkinson DJ, Hatzidakis AM, Balg F. Grammont reverse prosthesis: design, rationale and biomechanics. J Shoulder Elbow Surg 2005;14(Suppl):147-61. http://dx.doi.org/10.1016/j.jse.2004.10.006 Budge MD, Moravek JE, Zimel MN, Nolan EM, Wiater JM. Reverse total shoulder arthroplasty for the management of failed shoulder arthroplasty with proximal humeral bone loss: is allograft augmentation necessary. J Shoulder Elbow Surg 2013;22:739-44. http://dx.doi. org/10.1016/j.jse.2012.08.008 Carroll RM, Izquierdo R, Vazquez M, Blaine TA, Levine WN, Bigliani LU. Conversion of painful hemiarthroplasty to total shoulder arthroplasty: long-term results. J Shoulder Elbow Surg 2004;13:599603. http://dx.doi.org/10.1016/j.jse.2004.10.006 Cazeneuve J, Cristofari D. The reverse shoulder prosthesis in the treatment of fractures of the proximal humerus in the elderly. J Bone Joint Surg Br 2010;92:535-40. http://dx.doi.org/10.1302/0301-620X. 92B4.22450 Chacon A, Virani N, Shannon R, Levy JC, Pupello D, Frankle M. Revision arthroplasty with use of a reverse shoulder prosthesis allograft composite. J Bone Joint Surg Am 2009;91:119-27. http://dx.doi. org/10.2106/JBJS.H.00094 Cuff D, Clark R, Pupello D, Frankle M. Reverse shoulder arthroplasty for the treatment of rotator cuff deficiency. J Bone Joint Surg Am 2012;94:1996-2000. http://dx.doi.org/10.2106/JBJS.G.00775 Cuff D, Levy JC, Gutierrez S, Frankle MA. Torsional stability of modular and non-modular reverse shoulder humeral components in a proximal humeral bone loss mode. J Shoulder Elbow Surg 2011;20: 646-51. http://dx.doi.org/10.1016/j.jse.2010.10.026 Day JS, Lau E, Ong KL, Williams GR, Ramsey ML, Kurtz SM. Prevalence and projections of total shoulder and elbow arthroplasty in the United States to 2015. J Shoulder Elbow Surg 2010;18:1115-20. http://dx.doi.org/10.1016/j.jse.2010.02.009 De Wilde L, Boileau P, Van der Bracht H. . Does reverse shoulder arthroplasty for tumors of the proximal humerus reduce impairment? Clin Orthop Relat Res 2011;469:2489-95. http://dx.doi.org/10.1007/ s11999-010-1758-x Dines JS, Fealy S, Strauss EJ, Answorth A, Craig EV, Warren RF, et al. Outcomes analysis of revision total shoulder replacement. J Bone Joint Surg Am 2006;88:1494-500. http://dx.doi.org/10.2106/JBJS.D. 02946 Gruen TA, McNeice GM, Amstutz HC. ‘‘Modes of failure’’ of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop 1979;141:17-27. Hasan SS, Leith JM, Campbell B, Kapil R, Smith KL, Matsen FA 3rd. Characteristics of unsatisfactory shoulder arthroplasties. J Shoulder Elbow Surg 2002;11:431-41. http://dx.doi.org/10.1067/mse.2002.125806 Jain NB, Higgins LD, Guller U, Pietrobon R, Katz JN. Trends in the epidemiology of total shoulder arthroplasty in the United States from
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1990-2000. Arthritis Rheum 2006;55:591-7. http://dx.doi.org/10.1002/ art.22102 Kelly JD, Zhao JX, Hobgood R, Norris TR. Clinical results of revision shoulder arthroplasty using the reverse prosthesis. J Shoulder Elbow Surg 2012;21:1516-25. http://dx.doi.org/10.1016/j.jse.2011.11.021 Levy J, Fankle M, Mighell M, Pupello D. The use of the reverse shoulder prosthesis for the treatment of failed hemiathroplasty for proximal humeral fracture. J Bone Joint Surg Am 2007;89:292-300. http://dx.doi.org/10.2106/JBJS.E.01310 Levy J, Virani N, Pupello D, Frankle M. The use of the reverse shoulder prosthesis for the treatment of failed hemiarthoplasty in patients with glenohumeral arthritis and rotator cuff deficiency. J Bone Joint Surg Br 2007;89:189-95. http://dx.doi.org/10.1302/0301-620X. 89B2.18161 Moeckel BH, Altchek DW, Warren RF, Wickiewicz TL, Dines DM. Instability of the shoulder after arthroplasty. J Bone Joint Surg Am 1993;75:492-7. Patel DN, Young B, Onyekwelu I, Zuckerman JD, Kwon YW. Reverse total shoulder arthroplasty for failed shoulder arthroplasty. J Shoulder Elbow Surg 2012;21:1478-83. http://dx.doi.org/10.1016/j.jse.2011.11. 004 Petersen SA, Hawkins RJ. Revision of failed total shoulder arthroplasty. Orthop Clin North Am 1998;29:519-33. Rispoli DM, Sperling JW, Athwal GS, Schleck CD, Cofield RH. Humeral head replacement for the treatment of osteoarthritis. J Bone Joint Surg Am 2006;88:2637-44. http://dx.doi.org/10.2106/JBJS.E. 01383 Sajadi KR, Kwon YW, Zuckerman JD. Revision shoulder arthroplasty: an analysis of indications and outcomes. J Shoulder Elbow Surg 2010; 19:308-13. http://dx.doi.org/10.1016/j.jse.2009.05.016 Sanchez-Sotelo J, Sperling JW, Rowland C, Cofield RH. Instability after shoulder arthroplasty: results of surgical treatment. J Bone Joint Surg Am 2003;85:622-31. Simovitch RW, Helmy N, Zumstein MA, Gerber C. Impact of fatty infiltration of the teres minor muscle on the outcome of reverse total shoulder arthroplasty. J Bone Joint Surg Am 2007;89:934-9. http://dx. doi.org/10.2106/JBJS.F.01075 Sirveaux F, Favard L, Oudet D, Huguet D, Lautman S. Grammont inverted total shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive and non-repairable massive rupture of the cuff. Results of a multicenter study of 80 shoulders. J Bone Joint Surg Br 2004;86:388-95. http://dx.doi.org/10.1302/0301-620X.86B3.14024 Sperling JW, Cofield RH. Revision total shoulder arthroplasty for the treatment of glenoid arthrosis. J Bone Joint Surg Am 1998;80: 860-7. Walker M, Willis MP, Brooks JP, Pupello D, Mulieri PJ, Frankle MA. The use of the reverse shoulder arthroplasty for the treatment of failed total shoulder arthroplasty. J Shoulder Elbow Surg 2012;21:514-22. http://dx.doi.org/10.1016/j.jse.2011.03.006 Werner CM, Steinmann PA, Gilbart M, Gerber C. Treatment of painful pseudoparesis due to irreparable rotator cuff dysfunction with the Delta III reverse-ball-and-socket total shoulder prosthesis. J Bone Joint Surg Am 2005;87:1476-86. http://dx.doi.org/10.2106/JBJS.D. 02342 Wirth MA, Rockwood CA Jr. Complications of total shoulder-replacement arthroplasty. J Bone Joint Surg Am 1996; 78:603-16.
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The effect of proximal humeral bone loss on revision reverse total shoulder arthroplasty Scott P. Stephens, MDa,*, Kevin C. Paisley, DOb, M. Russell Giveans, PhDc, Michael A. Wirth, MDd a
Fondren Orthopedic Group, Houston, TX, USA University of Texas Health Science Center at San Antonio, San Antonio, TX, USA c Elite Research Institute, Minneapolis, MN, USA d Professor/Charles A. Rockwood, Jr., MD Chair, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA b
Background: Revision shoulder arthroplasty can be complicated by osseous and soft tissue deficiencies. Proximal humeral bone loss can result in diminished implant stability and reduced functional outcomes, and some studies have advocated the use of humeral allograft in this setting. This study compares the outcomes of revision reverse total shoulder arthroplasty (RTSA) in patients both with and without proximal humeral bone loss. Methods: During a 6-year period, 32 patients were revised to RTSA for failed shoulder hemiarthroplasty. Proximal humeral bone loss was found in 16 patients, with an average loss of 36.3 mm (range, 17.266 mm). Patients were followed up an average of 51.2 months with the American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, visual analog scale score for pain, subjective outcome ratings, and radiographs. Results: Significant improvement was found for average American Shoulder and Elbow Surgeons score (30.7 to 66.8), Simple Shoulder Test score (1.6 to 5.3), visual analog scale score (6.0 to 2.6), and forward flexion (51 to 100 ) but not for external rotation (15 to 19.1 ). No difference was demonstrated for functional or subjective outcomes compared with patients with intact humeral bone, except for active motion. On radiographic examination, 3 patients demonstrated humeral-sided loosening. Five complications were noted in patients with humeral bone loss. Conclusion: Revision RTSA can provide successful outcomes in the presence of proximal humeral bone loss without the use of allograft. Implant stability may be improved by the use of a cemented long-stem monoblock humeral prosthesis in revision settings. Level of evidence: Level III, Retrospective Cohort Design, Treatment Study. Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Proximal humeral bone loss; revision reverse total shoulder arthroplasty; failed shoulder arthroplasty; allograft-prosthesis composite
Institutional Review Board approval was provided by the University of Texas Health Science Center: No. HSC20010109H. *Reprint requests: Scott P. Stephens, MD, Fondren Orthopedic Group, 3100 Post Oak Blvd #551, Houston, TX 77056, USA. E-mail address: [email protected] (S.P. Stephens).
The prevalence of shoulder arthroplasty has continued to increase in the past decade, and projected estimations reveal a growth rate that exceeds lower extremity joint replacement.13,18 The increased number of shoulder
1058-2746/$ - see front matter Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. http://dx.doi.org/10.1016/j.jse.2015.02.020
2 replacements, though, will result in a proportional burden of revision cases. Shoulder arthroplasty can fail from either osseous or soft tissue deficiencies and result in pain, instability, hardware failure, infections, or loss of function.15,22,24,27 Failure can result from either a single cause or, as in a majority of patients, a combination of factors.4,16,17,33 This makes revision shoulder arthroplasty technically demanding, and it is demonstrated by reported outcomes to be inferior to primary shoulder arthroplasty.1,8,19,30,31 Identifying the cause of reconstruction failure can potentially optimize outcomes after revision surgery.26 Dines et al15 performed an outcomes analysis of shoulder arthroplasty and found that results could be predicted on the basis of the indication for the revision procedure, with soft tissue deficiencies producing inferior results. One potential factor that can affect preoperative planning for revision cases is proximal humeral osseous deficiency.12,20,21,33 Proximal humeral bone loss can result from prior surgeries, infection, or complex proximal humerus fractures in which the tuberosities progress to nonunion, malunion, or resorption.5 The loss of humeral bone stock can affect component fixation as well as disrupt the insertion of rotator cuff muscles.12,14 Reverse total shoulder arthroplasty (RTSA) has been effective in treating failed shoulder arthroplasty with soft tissue or bone loss because of its increased constraint and diminished reliance on an intact rotator cuff.3,20,23,31 This implant, though, relies on a preserved humeral bone stock for implant fixation, rotational stability, and soft tissue attachments to improve function and stability postoperatively.10,12,28,32 The loss of proximal humeral bone and associated soft tissue structures can thus play a pivotal role in a patient’s results and has led some to advocate the use of allograft-prosthesis composites.10,20 The goal of this study was to compare the outcomes for revision RTSA with and without proximal humeral bone loss. In addition, we compare the results of revision reverse shoulder arthroplasty in the setting of proximal humeral bone loss without the use of allograft to current literature.
Materials and methods This study was a retrospective case series of prospectively collected data. During a 6-year period from 2004 to 2010, 34 patients (22 women, 12 men) with a mean age of 70 years (range, 53-87 years) were treated for failed shoulder arthroplasty with a single-stage conversion to a reverse shoulder prosthesis (Delta Extend; DePuy, Warsaw, IN, USA). The study was part of an Institutional Review Board–approved prospective database collection, and all enrolled patients provided informed consent for the follow-up examinations and use of their data. Two patients without proximal humeral bone loss were lost to follow-up; attempts were made to contact them, but they were unable to be reached, leaving 32 patients in the study. The initial diagnosis for implantation of the 32 hemiarthroplasties was either a proximal
S.P. Stephens et al. humerus fracture (11) or rotator cuff tear arthropathy (21). Failure of the arthroplasty resulted from pain, progressing glenoid arthrosis, diminished function, or instability. All patients failed to respond to attempted conservative treatment consisting of physical therapy and activity modification. All revision procedures were performed by the senior author (M.A.W.). Patients were followed up clinically and radiographically for an average of 51 months (range, 24-130 months). Proximal humeral bone loss was identified in 50% (16 of 32) of the revision RTSAs, with the initial diagnosis consisting of proximal humerus fracture in 10 patients and rotator cuff tear arthropathy in 6 patients. The inclusion criteria for the study included any failed shoulder arthroplasty with pain or limited function that had failed nonoperative management, a functioning deltoid, and minimum 2year follow-up. Exclusion criteria were a nonfunctioning deltoid, infection, and inability to complete 2 years of follow-up.
Clinical assessment Patients were evaluated clinically with the use of the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST) score, and visual analog scale (VAS) score for pain. Scales for rating subjective outcomes were used to determine if there was sensation of instability, pain with active motion, and pain at rest. Range of motion was measured for forward flexion, external rotation, and internal rotation. Internal rotation was determined by the most proximal spinal level that the patient could reach.
Radiographic assessment All patients were evaluated with radiographs consisting of anteroposterior, scapular Y, internal and external Grashey, and axillary views. Preoperative radiographs were evaluated for instability, glenoid bone loss, glenoid arthrosis, proximal humeral bone loss, position of humeral head, and condition of the tuberosities. Glenohumeral subluxation was evaluated with regard to direction and the amount of translation of the center of the prosthetic head relative to the center of the glenoid, as described by Rispoli et al.25 Glenoid bone loss was determined by the use of the intraoperative classification by Antu~ na.2 Proximal humeral bone loss was calculated on postoperative radiographs by the method described by Budge et al.7 The condition of the tuberosities was evaluated for presence of malunion, nonunion, or resorption. Postoperative radiographs were evaluated for humeral loosening by the classification of Gruen et al16 adapted to the shoulder and classified according to width (2 mm). Loosening was defined as displacement of the humeral component between the time of the initial postoperative radiograph and the most recent follow-up or if radiolucency >2 mm was present in more than 3 zones. The glenoid component was assessed for the presence of scapular notching according to the Sirveaux-Nerot grading system.29 Any radiolucent lines around the glenoid screws, central peg, or baseplate were classified according to their width (2 mm). Loosening was considered to be present if the glenoid component had migrated, as demonstrated by shift, tilt, or subsidence, or if complete radiolucency >2 mm was present in each zone. Instability was classified as present or absent. Acromial fractures and locations were noted to involve either the acromion body or scapular spine. Heterotopic bone located on the inferior glenoid was identified and recorded.
Humeral bone loss and reverse arthroplasty
3
Surgical technique
Results
Patients were evaluated preoperatively for the possibility of subclinical infection with the use of complete blood count, C-reactive protein level, and erythrocyte sedimentation rate. The operative technique consisted of positioning the patient in a semi-Fowler position with the head secured and the arm draped free. All patients were given general anesthesia in addition to an intrascalene block. A deltopectoral approach was used for all patients and incorporation of pre-existing incisions. The upper border of the pectoralis major tendon was released to assist in exposure, and the subdeltoid and subacromial spaces were carefully freed of scar tissue. The tuberosities were evaluated, and if present, an attempt was made to reattach them to preserve posterior rotator cuff function and proximal bone stock. A subscapularis peel, if present, was performed and tagged for reattachment to improve postoperative stability. Extraction of the humeral prosthesis was performed with a combination of flexible osteotomes, high-speed bur, and implant extraction device. A humeral osteotomy was necessary in 12 patients to retrieve the humeral stem, and a fibular strut graft was applied to reinforce the native bone stock in 2 of these patients. In 1 patient, the posterior rotator cuff muscles were transferred to the remaining greater tuberosity. Intraoperative frozen section analysis was obtained to evaluate for >5 polymorphonuclear neutrophils per high-power field, and cultures were held for 2 weeks. After removal of the humeral implant, cement was removed only when necessary for component insertion. A complete capsular release surrounding the glenoid was performed as well as removal of heterotopic ossification to prevent soft tissue or bone impingement on the implant. Depending on the proximal bone stock, metaphyseal reaming was performed, and a trial implant was placed. The implant was reduced and evaluated for stability and gapping between the polyethylene and glenosphere in extension and external rotation and with adduction and internal rotation. The humeral component’s height was determined by soft tissue tension and stability of the prosthesis. If proximal bone loss was encountered, a fracture jig was applied to maintain the humeral component’s height and version. Monoblock humeral components were used in 10 of the patients with proximal bone loss, and modular components were used in the other 6 patients. Cement was used for fixation of the humeral component in all patients with proximal humeral bone loss. The overall operative time for patients with bone loss was found to be 37 minutes longer than for patients without bone loss. Postoperatively, the patient was placed in a sling, and motion was restricted to hand and elbow movement for the first month. After 4 weeks, gentle active and active assisted activities were begun. Strengthening was delayed until 3 months. Physical therapy was based on a home-directed stretching and strengthening program.
Overall, a significant improvement was noted in clinical outcomes after revision to RTSA in all 32 patients with increase in SST score (1.5 to 6.2; P < .001), ASES score (29.7 to 70.6; P < .001), and VAS score (6.4 to 1.9; P < .001). Range of motion also significantly improved in forward flexion (51 to 118 ; P < .001) and external rotation (15 to 27 ; P < .001). In the 16 patients undergoing revision RTSA with proximal humeral bone loss, a significant improvement in SST score (1.6 to 5.3; P < .001), VAS score (5.4 to 3.1; P ¼ .020), ASES score (30.7 to 66.8; P < .001), and forward flexion (52 to 100 ; P < .001) was demonstrated. There was not a significant improvement in external rotation (15 to 19.1 ; P ¼ .383). Significant improvements were also seen in the 16 patients who had intact proximal humeral bone stock for SST score (1.4 to 7.1; P < .001), VAS score (P < .001), ASES score (P < .001), forward flexion (52 to 135 ; P < .001), and external rotation (17 to 34 ; P ¼ .012). In comparing the group with bone loss to the intact proximal humerus group, there was no statistical difference in preoperative clinical assessment for SST score (1.6 vs. 1.4; P ¼ .953), VAS score (6.0 vs. 6.7; P ¼ .396), ASES score (30.7 vs. 28.8; P ¼ .703), forward flexion (51 vs. 52 ; P ¼ .926), or external rotation (15 vs. 17 ; P ¼ .727). Postoperatively, patients with proximal humeral bone loss had lower functional outcome scores and pain scores, but no statistical difference was found for ASES score (66.8 vs.74.4; P ¼ .503), SST score (5.3 vs. 7.1; P < .445), and VAS score (2.6 vs. 1.2; P ¼ .057). A significant difference, though, was found for postoperative range of motion, with the bone loss group having less forward flexion (100 vs. 135 ; P ¼ .022) and external rotation (19 vs. 34 ; P ¼ .009) (Table I). Preoperative radiographs revealed severe instability in 9 patients, moderate instability in 7 patients, mild instability in 13 patients, and no instability in the remaining patients. Glenoid erosion was severe in 6, moderate in 7, mild in 13, and none in 6. No difference in instability or glenoid erosion was found between the 2 groups. In the patients with proximal humeral bone loss, postoperative radiographs demonstrated an average proximal humeral bone loss of 36.3 mm (range, 17.2-66 mm). Glenoid notching was found in 27 patients, with grade 3 or 4 notching found in 5 patients with humeral bone loss and in only 2 patients without. No metaglene loosening was noted in either group. Humeral loosening was identified in 3 patients with proximal humeral bone loss, with 2 patients demonstrating stem subsidence (Fig. 1). No patients without humeral bone loss demonstrated humeral stem loosening. Nine patients had inferior glenoid heterotopic ossification in the bone loss group compared with 6 in the non–bone loss group. Complications occurred in 31% (5 of 16) of the patients with proximal humeral bone loss. One patient
Statistical analyses All variables were analyzed for normality by the Shapiro-Wilk test. Independent samples t tests and Mann-Whitney U tests were used to determine differences between groups, where appropriate. Paired samples t test and Wilcoxon tests were used to determine differences within groups from preoperative to postoperative, where appropriate. Statistical analyses were performed with SPSS v.21 (SPSS, Inc., Chicago, IL, USA). Significance was set at P < .05.
4
S.P. Stephens et al. Table I Clinical outcomes of revision RTSA with and without proximal humeral bone loss Variable
Age BMI Preoperative SST VAS1 VAS2 VAS3 VAS4 FF ER ASES Postoperative SST VAS1 VAS2 VAS3 VAS4 FF ER ASES Change SST VAS1 VAS2 VAS3 VAS4 FF ER ASES
Proximal humeral bone loss
Proximal humeral bone intact
P value
70.5 25.7
70.3 29.5
.953 .196
1.6 5.4 6.0 8.0 4.2 51.3 15.0 30.7
1.4 3.9 6.7 9.1 3.8 51.6 16.9 28.8
.642 .197 .396 .069 .7 .926 .727 .703
5.3 3.1 2.6 4.2 1.1 100.0 19.1 66.8
7.1 1.4 1.2 2.9 0.7 135.3 34.1 74.4
.133 .108 .057 .24 .477 .022 .009 .25
3.7 2.4 3.5 3.8 3.1 48.8 4.1 36.1
5.6 2.6 5.6 6.2 3.1 83.8 17.2 45.6
.113 .866 .138 .073 .752 .069 .092 .445
RTSA, reverse total shoulder arthroplasty; ASES, American Shoulder and Elbow Surgeons; SST, Simple Shoulder Test; VAS, visual analog scale; BMI, body mass index; ER, external rotation; FF, forward flexion.
sustained an intraoperative fracture of the proximal humerus during humeral stem removal. The fracture and osteotomy site were stabilized with a cerclage cable; the patient’s postoperative recovery was unaffected, and a successful outcome was achieved. Another patient sustained a postoperative periprosthetic humeral shaft fracture just distal to the tip of the prosthesis. The patient was treated conservatively and went on to a varus malunion. The patient had poor results (forward flexion of 30 , external rotation of 4 , ASES score of 63, and VAS score of 4). Another patient developed a hematoma that resulted in a temporary nerve palsy in the radial and median nerve distribution but resolved spontaneously within the first week. One patient sustained a dislocation 1 year after conversion to RTSA and had repeated instability after closed reduction necessitating a return to the operating room for placement of a spacer and increased polyethylene size. The patient had a successful
Figure 1 (A) Hemiarthroplasty with tuberosity resorption and proximal humeral bone loss that was revised to a reverse total shoulder with standard-length humeral component. (B) Distal migration of humeral stem from implant loosening despite the use of cement.
outcome and no more instability until he fell nearly 10 years later, resulting in a periprosthetic fracture that disrupted the humeral stem fixation. The patient was taken to the operating room for open reduction and internal fixation of the fracture. The patient had 6.6 cm of proximal humeral bone loss, and the intraoperative decision was made to apply a proximal humeral allograft composite to restore proximal bone loss and to allow
Humeral bone loss and reverse arthroplasty
5
Figure 2 (A) Patient with revision RTSA and severe proximal humeral bone loss who sustained a periprosthetic fracture and implant loosening. (B) Postoperative revision film demonstrating revised RTSA and humeral allograft placement and restoration of bone stock. (C and D) Final postoperative films demonstrate dislocated prosthesis. Scapular notching to the level of the inferior screw is also noted.
reimplantation of the humeral stem. The humeral stem was grossly loose at the time of surgery, and remaining proximal humeral bone was osteopenic. The allograft was prepared in a step-cut manner to optimize biomechanics of allograft to host bone stability and stabilized with an AO plate consisting of cerclage wires and multiple screws. The implant was cemented into the humeral allograft and the deltoid repaired to the allograft and remaining humeral bone. Two weeks after the surgery, radiographs revealed an atraumatic anteriorly dislocated prosthesis. The patient was taken back to the operating
room, and a 9-mm polyethylene with 9-mm spacer was implanted. Excellent soft tissue tension and stability were noted during range of motion, but at the 6-week followup, the patient was noted to have redislocated. No additional surgical management was performed (Fig. 2). Another patient was noted to have an acromion fracture that involved the scapular spine and was managed conservatively with a good outcome (forward flexion, 130 ; external rotation, 30 ; VAS score, 1.6). Only 1 complication was noted in the non–bone loss group and consisted of an acromion fracture. The patient was
6 managed conservatively and had a good outcome (ASES score, 95; forward flexion, 125 ; VAS score, 1).
Discussion Proximal humeral bone loss in the setting of revision shoulder arthroplasty can significantly affect humeral implant fixation and restoration of humeral length and disrupt soft tissue attachments and deltoid tensioning.6,10-12 Overall, we demonstrated significant improvement in all patients after revision surgery. No difference was found for postoperative functional or subjective outcomes scores in patients with proximal humeral bone loss compared with patients with intact humeral bone. Budge et al7 reviewed 15 patients revised to RTSA for failed arthroplasty with a comparable amount of average proximal humeral bone loss (38.4 vs. 36.3 mm) to our study. We found similar clinical outcomes for ASES score (68 vs. 67) and forward flexion (103 vs. 100 ), and although their final external rotation was less than ours, they did demonstrate greater overall improvement. This illustrates that consistent successful functional outcomes can be obtained after revision RTSA in patients with bone loss. We did find a significant difference in the final range of motion for patients with proximal humeral bone loss compared with patients without bone loss. Although reverse total shoulder implants have not been as successful in restoring external rotation compared with forward flexion, the loss of external rotator attachments may explain why patients with bone loss improved on average only by 4 of external rotation compared with 17 for patients with intact greater tuberosities.28 This was also shown by Budge et al,7 who found that although external rotation did improve, it was not found to be significant, and improvement of external rotation lag sign was seen in only 4 of 10 patients. Although other authors have recommended the removal of tuberosities to eliminate a source of impingement that may lead to dislocation,9 we prefer to attempt repair of the tuberosities, if they are present, to increase bone stock and attempt to restore the rotator cuff tension and function. Restoration of anatomic tuberosity position can also assist in re-establishing deltoid tension. If the tuberosity is not able to be restored to its anatomic location, consideration should be given to latissimus dorsi transfer at the time of revision surgery in an attempt to gain active external rotation. The loss of proximal humeral bone can also disrupt the deltoid attachment, specifically the anterior deltoid, and could explain the difference found in forward flexion. The effect of proximal humeral bone loss on humeral implant fixation was studied by Cuff et al,12 who biomechanically compared the stability of humeral stems with a bone loss construct. They demonstrated increased rotational micromotion in the bone loss group as well as more documented component failures. All 5 of their implant failures consisted of modular component prostheses.
S.P. Stephens et al. Boileau et al6 reported on 37 patients undergoing revision RTSA surgery and found that humeral component complications represented 21% of revision surgeries and were the second most common reason to revise an RTSA. They noted that humeral bone loss was >30 mm in all 10 cases of humeral loosening and implant derotation. We found that 19% (3 of 16) of the patients in the bone loss group had humeral implant loosening, with 2 of these stems demonstrating implant subsidence. These 3 patients had between 2.1 and 3.8 cm of humeral bone loss. The humeral migration significantly affected the patient’s results, with poor functional outcomes, pain scores, and range of motion (patient 1: ASES score of 31.6, external rotation of 0 , VAS score of 7; patient 2: ASES score of 43, external rotation of 5 , VAS score of 5.4). Although these patients did not require a return to the operating room, the distal migration may have resulted in alteration of humeral length and subsequent changes in soft tissue tension as well as discomfort from implant instability. All 3 of these patients had standard-length humeral components, and we would recommend long-stem humeral components for all revision procedures to improve implant fixation. Although 6 of our patients had modular components, we did not have any implant dissociations but agree that a monoblock component would prevent increased stress on the modular metaphyseal humeral components. This was also demonstrated by Boileau et al6 in their series, in which 5 patients with component separation required a revision to a monoblock stem, and by Budge et al,7 whose only component fracture occurred in a patient with a modular prosthesis that was unsupported by metaphyseal bone. Recent reports have advocated the use of an allograftprosthetic composite in the setting of proximal humeral bone loss to restore bone stock, to increase implant fixation, to allow reattachment of the subscapularis, to maintain prosthesis height, and to improve the mechanical advantage of the deltoid by providing lateral offset.10,20 Levy et al20 reviewed 29 patients who underwent revision to RTSA after failed hemiarthroplasty for fracture, of which 8 patients were managed with an allograft reverse shoulder prosthesis. All functional scores, except forward flexion, showed trends of increased improvement in patients treated with an allograft-prosthesis construct, and 75% (6 of 8) rated their results good or excellent compared with 48% (10 of 21) treated with prosthesis alone. Chacon et al10 performed a follow-up study of 25 patients with an average bone loss of 53.6 mm that used an allograft-prosthesis composite. They demonstrated improvements similar to those of our study in functional outcomes (ASES score, 69 vs. 67; SST score, 4.5 vs. 5.3) and active motion (forward flexion, 50 vs. 49 ). On radiographic examination, 2 patients had graft resorption, 2 had graft fragmentation, and 4 others had no incorporation at the allograft-host junction. Budge et al,7 in their study of humeral bone loss, did not advocate the use of a proximal humeral allograft because long humeral stems and the semiconstrained nature of the
Humeral bone loss and reverse arthroplasty prosthesis can provide implant stability, and the soft tissue surrounding the proximal humerus was no longer present in their patients. Our results were similar to those of Budge et al and demonstrate that similar functional outcomes can be obtained with a reverse prosthesis alone and that humeral length, implant height, and deltoid tension can be restored with the proper use of a fracture jig, cement, and an attempt to restore the greater tuberosity to its anatomic position. Although we obtained outcomes similar to those reported by Chacon et al,10 their cohort did have an increased average bone loss as seen in our study, and the exact amount of bone loss that may benefit from augmentation of proximal humeral bone stock to improve implant fixation, stability, and deltoid tensioning is still unknown. Complications were found in 31% (5 of 16) of the patients with proximal humeral bone loss compared with only 1 patient in the intact humeral bone stock group. We found that the complication rate for patients undergoing revision without proximal humeral bone loss was encouraging, and although more complications were found in patients with bone loss, only 1 patient required a return to the operating room as the result of a periprosthetic fracture after a fall. We had only 1 patient with postoperative instability and no component failures. These results were similar to those of Budge et al,7 who reported that 47% (7 of 15) of the patients with bone loss had complications, but only 2 required a return to the operating room. This is in comparison to Chacon et al,10 who noted 5 patients with complications, including 2 patients who required a return to the operating room. One patient required a revision allograft placement after falling and fracturing the allograft and polyethylene component; postoperatively, the patient had recurrent instability that resulted in another revision to a larger glenosphere to gain stability. Another patient required removal of the allograft because of infection within a few weeks after the revision surgery. This is consistent with problems associated with allograft placement reported in the literature involving graft resorption, nonunion, and failure.20 We did identify scapular notching in 88% (14 of 16) of the patients with proximal humeral bone loss, including 5 patients with severe notching, compared with none in the study by Chacon et al.10 This may be the result of the Grammont-style prosthesis used in this study that has an increased neck-shaft angle, and longer follow-up will be needed to determine whether this results in metaglene loosening. The present study had several limitations. The study involved a tertiary referral center with an experienced shoulder surgeon, and these results may not translate to other practices. Second, although the data were collected prospectively, they were reviewed retrospectively and subject to this inherent limitation. This study would have been strengthened by an equal number of patients who had allograft-prosthesis composite placement to directly compare outcomes. This study, though, is strengthened by the high percentage of patient retention as well as by the long clinical and radiographic follow-up duration.
7
Conclusion Revision shoulder arthroplasty in the setting of proximal humeral bone loss offers many technical challenges to the surgeon, but our results demonstrate that successful outcomes can be obtained with the use of a reverse shoulder prosthesis. Although significantly less active motion was found in patients with proximal humeral bone loss, no difference was found for functional and subjective outcome scores compared with patients without bone loss in a revision setting. Overall, all functional variables increased in patients with proximal humeral bone loss except for external rotation. A higher incidence of humeral stem loosening, though, was found in patients with proximal humeral bone loss, and subsidence was demonstrated with the use of a standardlength prosthesis. Although allograft can successfully restore proximal humeral bone stock and potentially improve implant fixation that may be required in some cases, we think that equivalent clinical and radiographic results can be obtained without the use of an allograftprosthesis composite and its associated technical difficulty. Our results support the use of a long-stem monoblock prosthesis to diminish humeral-sided component failure and that consideration should also be given to tendon transfers to improve active external rotation at the time of revision surgery if a preoperative deficit is present. This study illustrates that successful outcomes can be obtained in revision reverse shoulder arthroplasty in the presence of proximal humeral bone loss and that further studies will be needed to determine the proper use of allograft in this setting.
Disclaimer The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
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