302 C OPYRIGHT Ó 2014
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T HE J OURNAL
OF
B ONE
AND J OINT
S URGERY, I NCORPORATED
Displaced Intra-Articular Calcaneal Fractures Treated in a Minimally Invasive Fashion Longitudinal Approach Versus Sinus Tarsi Approach Tao Zhang, MD*, Yanling Su, MD, MPH*, Wei Chen, MD, PhD, Qi Zhang, MD, PhD, Zhanpo Wu, MD, PhD, and Yingze Zhang, MD Investigation performed at the Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, Republic of China
Background: The optimal treatment for displaced intra-articular fractures of the calcaneus remains controversial. This study aims to assess the clinical outcomes of a minimally invasive longitudinal approach compared with the sinus tarsi approach in the surgical treatment of these fractures. Methods: Patients with a displaced intra-articular fracture of the calcaneus who were admitted to the trauma center of our hospital from September 2009 through April 2010 were randomly assigned to treatment using one of these two surgical techniques. All patients underwent the same standardized postoperative rehabilitation protocol. Functional outcome was assessed by using the American Orthopaedic Foot & Ankle Society scores. Linear regression analysis was performed to identify the potential influencing factors for functional outcomes. Results: One hundred and sixty-seven patients who met the inclusion criteria were included in the study. Thirty-seven patients were lost to follow-up for various reasons, and the remaining 130 patients were followed for an average of twentyseven months. Sixty-nine fractures in sixty-three patients were treated using a minimally invasive longitudinal approach (the MILA group), and seventy-two feet in sixty-seven patients were treated with a sinus tarsi approach (the STA group). The two groups were comparable in terms of age, sex, fracture type, and time from injury to operation. The operative time in the MILA group was significantly shorter than that in STA group (p < 0.05). Wound-healing complications were 2.9% in the MILA group and 12.5% in the STA group. The average time to the start of progressive weight-bearing exercise was 5.3 weeks in the MILA group and 5.6 weeks in the STA group (p > 0.05). The good and excellent results in the two groups were comparable for the Sanders type-II and III calcaneal fractures (p > 0.05), but the good to excellent rate in the STA group was significantly higher for the Sanders type-IV fractures (p < 0.05). Linear regression analysis showed that surgical technique, Sanders classification, and the time to the start of weight-bearing activity have a significant influence on functional outcomes. Conclusions: Outcomes are similar for the minimally invasive longitudinal and sinus tarsi surgical approaches in the treatment of Sanders type-II and III displaced intra-articular fractures of the calcaneus, with the benefit of a lower complication rate and shorter operative time for the minimally invasive technique. For Sanders type-IV fractures, however, the sinus tarsi approach appears to be the treatment of choice. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
T
he optimal surgical approach for the accurate reduction of a displaced intra-articular fracture of the calcaneus, while minimizing wound-related complications, remains
controversial. One of the most commonly used methods in clinical practice is open reduction and internal fixation through an extended lateral approach1,2. Unfortunately, the wound
*Tao Zhang, MD, and Yanling Su, MD, MPH, contributed equally to the preparation of this article. Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
J Bone Joint Surg Am. 2014;96:302-9
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TABLE I Operative Information on the Patients in the Two Groups General Information
MILA Group*
STA Group*
P Value
Age† (yr)
39.8 ± 11.9
41.7 ± 10.0
0.216
Sex Male Female
56 7
58 9
Sanders classification (no. of feet) Type II Type III Type IV
32 23 14
29 27 16
Injured foot Unilateral Bilateral
57 6
62 5
5.8 ± 1.8
6.3 ± 1.8
0.051
45.9 ± 18.2
61.9 ± 15.3
0.001
0.687
0.764
0.673
Time from injury to operation† (days) Operative time† (min)
*MILA = minimally invasive longitudinal approach, and STA = sinus tarsi approach. †The values are given as the mean and the standard deviation.
complication rate has been reported to be as high as 30% in patients treated with this approach3,4. The soft-tissue envelope over the lateral wall of the hindfoot is particularly thin and vulnerable, potentially creating a high risk for wound-related complications5,6. Carr7 recommended minimally invasive approaches to treat displaced intra-articular calcaneal fractures, and various minimally invasive approaches7-12 have been introduced to minimize the wound complication rate. Some of these approaches have been effective in lowering the prevalence of wound-related complications5,13-18. The sinus tarsi approach has become one of the most frequently applied minimally invasive approaches because of its ability to provide adequate exposure for the posterior facet, the anterolateral fragment, and the lateral
wall. Wound complication rates with this approach have been reported to range from 0% to 15.4%12. In an effort to decrease the wound complication rate and shorten the operative time, we introduced, in 2004, a minimally invasive approach that features a small longitudinal lateral incision on the hindfoot and the use of a plate and compression bolts19. A large clinical study 20 carried out by our team found that the functional outcome after the minimally invasive longitudinal approach was as good as, if not better than, the traditional L-shaped extensile lateral approach with the benefit of a significantly lower complication rate. The aim of the present study was to compare the clinical outcomes of the widely used sinus tarsi approach with those of the minimally invasive longitudinal approach.
TABLE II Soft-Tissue Complications MILA Group* (N = 69) Complications
STA Group* (N = 72)
No. of Feet
Percentage
No. of Feet
Percentage
P Value
Wound-healing complications Superficial infection Deep infection Wound-edge necrosis
2 2 0 0
2.9
9 5 2 2
12.5
0.034
Sural nerve injury
1
1.5
3
4.2
–
Medial plantar nerve injury and restricted movement of flexor hallucis longus tendon
4
5.8
3
4.2
–
Severe defect with plate removal
2
2.9
3
4.2
–
Total
7
10.1
13
18.1
*MILA = minimally invasive longitudinal approach, and STA = sinus tarsi approach.
0.178
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treat a unilateral fracture or were placed in the prone position for bilateral fractures. The reduction and fixation technique using the minimally invasive 19,20 longitudinal approach has been described in detail in our previous studies . A 3.5-cm longitudinal incision is made over the posterior part of the lateral aspect of the hindfoot along the lateral border of the Achilles tendon (Fig. 1). Steinmann pins are used to restore the B¨ohler angle and posterior articular facet by percutaneous leverage. The fracture is fixed with an anatomical plate and two, three, or four compression bolts in a minimally invasive manner. The quality of the reduction is assessed intraoperatively with use of a C-arm fluoroscopic image intensifier. 12 The standard sinus tarsi approach to the calcaneus provides direct exposure for reduction of the posterior facet. The anatomical plate and compression bolts can be applied by inserting them subcutaneously (Fig. 2).
Postoperative Management and Follow-up
Fig. 1
A 3.5-cm longitudinal incision is made over the posterior part of the lateral aspect of the hindfoot along the lateral border of the Achilles tendon. The anatomical plate is introduced through the incision in a subcutaneous tunnel. The red line indicates the minimally invasive longitudinal approach. 1 = the superficial peroneal nerve, and 2 = the sural nerve.
Materials and Methods
P
atients with a displaced intra-articular calcaneal fracture, who were admitted to the trauma center of our hospital from September 2009 through April 2010, were randomly assigned to two groups for surgical treatment with either a minimally invasive longitudinal approach (the MILA group) or a sinus tarsi approach (the STA group). One researcher on our team who was not involved in the clinical treatment of patients used a random-number table to divide the patients into the two groups. The six senior surgeons on our team, all with more than ten years of clinical experience in treating displaced intraarticular calcaneal fractures, were familiar with both minimally invasive approaches. The surgeons were numbered from 1 to 6 and were assigned to perform the operations using either the minimally invasive longitudinal approach or the sinus tarsi approach in turn. This assignment mechanism provides each surgeon with similar opportunities to perform both approaches and subsequently minimizes the bias among different surgeons. The inclusion criteria were a displaced intra-articular calcaneal fracture, an age of eighteen years or older, and no polytrauma of the ipsilateral lower limb at the time of admission. Patients who had severe medical ailments or declined to accept the assigned treatment algorithm were excluded. All calcaneal fractures in both groups were fixed with the same implants, that is, anatomic plates and multiple compression bolts. The Ethical Board Review of the Third Hospital of Hebei Medical University (Shijiazhuang, Hebei, China) approved the conduct of the study, and each patient provided informed consent. The study was performed in accordance with the ethical standards of the Declaration of Helsinki of 1964. The study was registered in the registry of the Health Department of Hebei Province (05276403D-16).
CTscans and radiographs of the injured feet were made right after the operation to evaluate the quality of the reduction and the fixation of the fracture (see Appendix), and the most obvious displacement of the posterior facet was measured on the sagittal and coronal views of the CT images. Non-weightbearing exercises, including extension and plantar flexion of the toes and ankle, were encouraged as soon as the pain could be tolerated. Crutch-assisted walking was allowed two or three days postoperatively. Partial weight-bearing was encouraged to begin at four weeks after the operation and to progress gradually. Full weight-bearing was allowed with evidence of osseous union on the radiographs, generally at three months postoperatively. The patients were seen for follow-up at six weeks and at three, six, and twelve months after the operation and then yearly thereafter. A physical examination was performed, and lateral and axial radiographs of the injured foot were made at each follow-up evaluation. The B¨ohler angle was measured on the lateral radiographs of the calcaneus. A CT scan was performed at the time of the three-month follow-up. Hardware was removed routinely for each patient at twelve months unless the patient had indications for earlier hardware removal.
Functional Outcome Evaluation The functional outcomes were evaluated according to the American Ortho21 paedic Foot & Ankle Society (AOFAS) hindfoot scores at the time of the twenty-four-month follow-up. The functional outcomes and complications were assessed and recorded by an independent surgeon who was blinded to the study design and the group assignment.
Preoperative Management All patients underwent preoperative calcaneal lateral and axial radiographs and a computed tomography (CT) scan of the injured foot. The injury severity was graded according to the Sanders classification on the basis of the CT scan findings. When the swelling subsided and wrinkles appeared on the hindfoot, the fractures were treated surgically. Fig. 2
Surgical Procedure
The sinus tarsi approach permits direct visualization of the articular sur-
Under either epidural or spinal anesthesia, patients were placed in the lateral decubitus position with the lateral malleolus of the affected foot uppermost to
face, and the anatomical plate can be applied through the horizontal incision (red line). 1 = the superficial peroneal nerve, and 2 = the sural nerve.
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Fig. 3
CONSORT
42
(Consolidated Standards of Reporting Trials) flow diagram.
Statistical Analysis On the basis of the functional outcomes of a preliminary study, a total sample size of not less than 165 patients was thought to be required to perform the statistical analysis. Continuous variables with non-normal distribution were analyzed with the Mann-Whitney U test. The non-paired t test was used to compare variables with a normal distribution. Categorical data were statistically analyzed by means of a chi-square test or Fisher exact test (n < 40 or t < 1). Four factors that may influence the functional outcome of displaced intra-articular calcaneal fractures were selected for evaluation: patient age, surgical technique (the minimally invasive longitudinal approach or the sinus tarsi approach), Sanders classification, and the time to the start of weight-bearing activity. Multinomial linear regression was used to analyze the relationship between functional recovery and these four factors. The categorical variables of surgical techniques, that is, the sinus tarsi approach and the minimally invasive longitudinal approach, were assigned a value of 0 and 1, respectively; and Sanders type-II, III, and IV fractures were assigned a value of 2, 3, and 4, respectively. A p value of 0.05). During subsequent measurements of the B¨ohler angle, no significant change was observed. According to the immediate postoperative CT scan, five of the sixty-nine fractures in the MILA group had articular incongruity of >3 mm and all five were Sanders type IV, while all seventy-two fractures in the STA group were reduced with 0.05). Patients in the STA group had better outcomes on all of the four subjective variables than patients in the MILA group. However, the two groups were only significantly different with regard to the variable of walking surface in the AOFAS scoring system (see Appendix). Of the patients who achieved good or excellent results in the MILA group, thirty-two had a type-II fracture; twenty-one, a type-III fracture; and two, a type-IV fracture. Of the patients who achieved good or excellent results in the STA group, twentynine had a type-II fracture; twenty-five, a type-III fracture; and nine, a type-IV fracture. Patients with Sanders type-II or III fractures in both groups had similar function outcomes (p = 1.000) (Table IV). However, for Sanders type-IV fractures, the good to excellent rate in the STA group was significantly higher than that in the MILA group (56.3% versus 14.3%; p < 0.05). Multinomial Linear Regression Analysis The multinomial linear regression analysis identified significant influencing factors for functional outcomes (F = 51.72,
p < 0.05). Three factors, including surgical technique, the Sanders classification, and the time to start weight-bearing activity, were found to be associated with the functional outcome (p < 0.05 for all; Table V). Discussion alcaneal fractures account for 2% of all fractures, and 80% to 90% of those fractures involve young adults22. As some patients who are treated nonoperatively for displaced intraarticular calcaneal fractures are unable to return to their original occupations or even completely lose the ability to work because of severe residual disability 23, surgical treatment has been recommended. However, the high complication rate presents challenges to the orthopaedic surgeon. The prevalence of wound-related complications after surgical treatment of calcaneal fractures has been reported to range from 7.57% to 32.8%3,24-26, and the neurovascular injury rate has been reported to range from 9.1% to 25%24,25,27.Various minimally invasive approaches have been developed to reduce the wound-related complication rates. Among them, the sinus tarsi approach has become one of the more popular minimally invasive methods as it can provide direct visualization of the posterior articular facet and has fewer soft-tissue-related complications12,28. Schepers reported an average wound complication rate of 4.8% (range, 0% to 15.4%) for patients treated with use of the sinus tarsi approach12. In 2004, we developed the minimally invasive longitudinal approach. This method has proven to be quite effective in treating displaced intra-articular calcaneal fractures compared with the open technique19,20. As part of our ongoing efforts to assess the clinical effectiveness of the minimally invasive longitudinal approach in the treatment of calcaneal fractures, we designed this study to compare the functional outcomes of the minimally invasive longitudinal approach with those of the sinus tarsi approach, using the AOFAS score29. The multinomial linear regression analysis showed that posterior facet displacement was associated with the functional outcome of calcaneal fractures. The Sanders classification can accurately reflect the severity of calcaneal fractures and the displacement of the posterior facet, which is one of the most important factors affecting the functional outcomes. Buckley et al.2 suggested that comminuted fractures were associated with a higher risk of poor outcomes regardless of the treatment method. The regression analysis also showed that the surgical
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method can affect the functional outcome. Using the minimally invasive longitudinal approach to treat all types of calcaneal fractures carries a risk of inadequate joint reconstruction. Biomechanical studies with pressure-sensitive films have revealed that even a minor residual step-off of the posterior facet may lead to a significant load shift within the subtalar joint30 and have an adverse effect on functional outcome31-33. According to the radiographic data, patients with Sanders type-II and III fractures in both groups had similar fracture reduction quality. However, for type-IV fractures or comminuted joint depression fractures, it appears that the sinus tarsi approach can yield a clearly better reduction of the articular surface than the minimally invasive longitudinal approach. The difference in the quality of articular reduction between the two groups may contribute to different functional outcomes. The analysis of the AOFAS scores according to the Sanders classification demonstrated no significant difference between the two approaches with regard to functional recovery for Sanders type-II and III calcaneal fractures. For Sanders type-IV fractures, however, the sinus tarsi approach can yield better functional outcomes than the minimally invasive longitudinal approach. The regression analysis showed that early weight-bearing activity, as part of the postoperative protocol, may affect the clinical outcomes. Clinical studies have also shown that patients with early postoperative weight-bearing activity may have better functional outcomes34,35. If reliable fixation can be achieved, then the earlier that weight-bearing activity is started, the better the functional outcomes that can be attained. In our study, the anatomic plate and compression bolts provided rigid fixation of the calcaneal fractures, which enabled partial weight-bearing as early as about four weeks after surgery when the pain had subsided. In contrast, the recommended amount of time for non-weight-bearing after other surgical methods has been reported to range from eight to ten weeks36. Pozo et al.37 reported that weight-bearing can lead to molding of the articular surface, which will help to restore the congruity of the subtalar joint. Our radiographic evaluation revealed some decreased articular step-off of the posterior facet in both groups after three months of weight-bearing. In addition, patients with prolonged non-weight-bearing usually develop osteoporosis and joint stiffness34, which is associated with a poor outcome in these fractures. Kingwell et al.38 reported that the range of subtalar motion after the surgery can directly affect patient satisfaction. In addition, a shortened non-weight-bearing time may postpone the development of posttraumatic subtalar arthritis20,35. In the current study, evidence of subtalar arthritis was observed on the CT scan of eight feet (5.6%), less than that reported in previous studies (6.25% to 12.90%)4,25,32,37,39,40. The wound-healing complication rate was 2.9% in the MILA group, significantly lower than the 12.5% rate in the STA
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group. The minimized disturbance to the blood supply of the lateral aspect of the hindfoot17 and the significantly shorter operative time in the MILA group may contribute to the lower rate of superficial wound complications as well as wound-edge necrosis. Furthermore, the minimally invasive longitudinal approach has a low risk of sural nerve injury. The course of the incision in the minimally invasive longitudinal approach is parallel to the proximal part of the sural nerve, and inserting the anatomic plate transversely can avoid injury to the distal part of the sural nerve. While the nuts used in the current study were of smaller size than in the past, care should be taken as their use still may lead to medial plantar nerve injury, skin irritation, and flexor hallucis longus tendon restriction. There are some limitations of the current study. First, 22.2% of the patients were either lost to follow-up or declined to participate in postoperative follow-up, which lowered the total sample size and weakened the statistical power of the final results. In addition, the AOFAS score, as the main outcome measure, has its own limitations, which may compromise the results. It has been criticized for its mathematical shortcomings, and the reliability of the score has yet to be proven41. Another limitation is that the two limbs in an individual should not be considered to be independent. However, we did not exclude the patients with bilateral calcaneal fractures, which may also be considered a limitation of the study design. Finally, the quantified data on the fracture reduction were not specifically analyzed. Appendix A table showing a comparison of the postoperative AOFAS scores and figures demonstrating the radiographs and CT scans of a calcaneal fracture in a thirty-three-year-old man are available with the online version of this article as a data supplement at jbjs.org. n
Tao Zhang, MD Yanling Su, MD, MPH Wei Chen, MD, PhD Qi Zhang, MD, PhD Zhanpo Wu, MD, PhD Yingze Zhang, MD Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, 139 Ziqiang Road, Shijiazhuang 050051, Hebei, Republic of China. E-mail address for T. Zhang: [email protected]. E-mail address for Y. Su: [email protected]. E-mail address for W. Chen: [email protected]. E-mail address for Q. Zhang: [email protected]. E-mail address for Z. Wu: [email protected]. E-mail address for Y. Zhang: [email protected].
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3. Abidi NA, Dhawan S, Gruen GS, Vogt MT, Conti SF. Wound-healing risk factors after open reduction and internal fixation of calcaneal fractures. Foot Ankle Int. 1998 Dec;19(12):856-61. 4. Lim EV, Leung JP. Complications of intraarticular calcaneal fractures. Clin Orthop Relat Res. 2001 Oct;(391):7-16. 5. Rammelt S, Amlang M, Barthel S, Zwipp H. Minimally-invasive treatment of calcaneal fractures. Injury. 2004 Sep;35(Suppl 2):SB55-63. 6. Cavadas PC, Landin L. Management of soft-tissue complications of the lateral approach for calcaneal fractures. Plast Reconstr Surg. 2007 Aug;120(2):459-66; discussion 467-9. 7. Carr JB. Surgical treatment of intra-articular calcaneal fractures: a review of small incision approaches. J Orthop Trauma. 2005 Feb;19(2):109-17. 8. Palmer I. The mechanism and treatment of fractures of the calcaneus; open reduction with the use of cancellous grafts. J Bone Joint Surg Am. 1948 Jan;30(1):2-8. 9. Wiley WB, Norberg JD, Klonk CJ, Alexander IJ. ‘‘Smile’’ incision: an approach for open reduction and internal fixation of calcaneal fractures. Foot Ankle Int. 2005 Aug;26(8):590-2. 10. Schepers T, Kieboom BC, Bessems GH, Vogels LM, van Lieshout EM, Patka P. Subtalar versus triple arthrodesis after intra-articular calcaneal fractures. Strategies Trauma Limb Reconstr. 2010 Aug;5(2):97-103. Epub 2010 Mar 23. 11. Gould N. Lateral approach to sinus tarsi. Foot Ankle. 1983 Jan-Feb;3(4):244-6. 12. Schepers T. The sinus tarsi approach in displaced intra-articular calcaneal fractures: a systematic review. Int Orthop. 2011 May;35(5):697-703. Epub 2011 Feb 19. 13. Stehlı´k J, Stulı´k J. [Combined method of treating dislocated fractures of the calcaneus]. Acta Chir Orthop Traumatol Cech. 2002;69(4):209-18. 14. Tornetta P 3rd. Percutaneous treatment of calcaneal fractures. Clin Orthop Relat Res. 2000 Jun;(375):91-6. 15. Gavlik JM, Rammelt S, Zwipp H. Percutaneous, arthroscopically-assisted osteosynthesis of calcaneus fractures. Arch Orthop Trauma Surg. 2002 Nov;122(8):424-8. Epub 2002 Jun 20. 16. Levine DS, Helfet DL. An introduction to the minimally invasive osteosynthesis of intra-articular calcaneal fractures. Injury. 2001 May;32(Suppl 1):SA51-4. 17. Stein H, Rosen N, Lerner A, Kaufman H. Minimally invasive surgical techniques for the reconstruction of calcaneal fractures. Orthopedics. 2003 Oct;26(10):1053-6. 18. Tornetta P 3rd. The Essex-Lopresti reduction for calcaneal fractures revisited. J Orthop Trauma. 1998 Sep-Oct;12(7):469-73. 19. Wang Q, Chen W, Su Y, Pan J, Zhang Q, Peng A, Wu X, Wang P, Zhang Y. Minimally invasive treatment of calcaneal fracture by percutaneous leverage, anatomical plate, and compression bolts—the clinical evaluation of cohort of 156 patients. J Trauma. 2010 Dec;69(6):1515-22. 20. Wu Z, Su Y, Chen W, Zhang Q, Liu Y, Li M, Wang H, Zhang Y. Functional outcome of displaced intra-articular calcaneal fractures: a comparison between open reduction/internal fixation and a minimally invasive approach featured an anatomical plate and compression bolts. J Trauma Acute Care Surg. 2012 Sep;73(3):743-51, doi:10.1097/TA.0b013e318253b5f1. 21. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int. 1994 Jul;15(7):349-53. 22. Cohen MM. Trauma of the foot and leg. In: Banks SA, ed. McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2001. p 1819. 23. Potter MQ, Nunley JA. Long-term functional outcomes after operative treatment for intra-articular fractures of the calcaneus. J Bone Joint Surg Am. 2009 Aug;91(8):1854-60.
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24. Buckley RE, Meek RN. Comparison of open versus closed reduction of intraarticular calcaneal fractures: a matched cohort in workmen. J Orthop Trauma. 1992;6(2):216-22. 25. Sanders R. Displaced intra-articular fractures of the calcaneus. J Bone Joint Surg Am. 2000 Feb;82(2):225-50. 26. Folk JW, Starr AJ, Early JS. Early wound complications of operative treatment of calcaneus fractures: analysis of 190 fractures. J Orthop Trauma. 1999 Jun-Jul; 13(5):369-72. 27. Paley D, Hall H. Intra-articular fractures of the calcaneus. A critical analysis of results and prognostic factors. J Bone Joint Surg Am. 1993 Mar;75(3):342-54. 28. Hospodar P, Guzman C, Johnson P, Uhl R. Treatment of displaced calcaneus fractures using a minimally invasive sinus tarsi approach. Orthopedics. 2008 Nov;31(11):1112. 29. Schepers T, Heetveld MJ, Mulder PG, Patka P. Clinical outcome scoring of intraarticular calcaneal fractures. J Foot Ankle Surg. 2008 May-Jun;47(3):213-8. Epub 2008 Mar 28. 30. Mulcahy DM, McCormack DM, Stephens MM. Intra-articular calcaneal fractures: effect of open reduction and internal fixation on the contact characteristics of the subtalar joint. Foot Ankle Int. 1998 Dec;19(12):842-8. 31. Song KS, Kang CH, Min BW, Sohn GJ. Preoperative and postoperative evaluation of intra-articular fractures of the calcaneus based on computed tomography scanning. J Orthop Trauma. 1997 Aug;11(6):435-40. 32. Crosby LA, Fitzgibbons T. Intraarticular calcaneal fractures. Results of closed treatment. Clin Orthop Relat Res. 1993 May;(290):47-54. 33. Gavlik JM, Rammelt S, Zwipp H. The use of subtalar arthroscopy in open reduction and internal fixation of intra-articular calcaneal fractures. Injury. 2002 Jan;33(1):63-71. 34. Talarico LM, Vito GR, Zyryanov SY. Management of displaced intraarticular calcaneal fractures by using external ring fixation, minimally invasive open reduction, and early weightbearing. J Foot Ankle Surg. 2004 Jan-Feb;43(1):43-50. 35. Hyer CF, Atway S, Berlet GC, Lee TH. Early weight bearing of calcaneal fractures fixated with locked plates: a radiographic review. Foot Ankle Spec. 2010 Dec;3(6):320-3. Epub 2010 Jun 10. 36. Schepers T, van Lieshout EM, van Ginhoven TM, Heetveld MJ, Patka P. Current concepts in the treatment of intra-articular calcaneal fractures: results of a nationwide survey. Int Orthop. 2008 Oct;32(5):711-5. Epub 2007 Jun 13. 37. Pozo JL, Kirwan EO, Jackson AM. The long-term results of conservative management of severely displaced fractures of the calcaneus. J Bone Joint Surg Br. 1984 May;66(3):386-90. 38. Kingwell S, Buckley R, Willis N. The association between subtalar joint motion and outcome satisfaction in patients with displaced intraarticular calcaneal fractures. Foot Ankle Int. 2004 Sep;25(9):666-73. 39. Sl¨atis P, Kiviluoto O, Santavirta S, Laasonen EM. Fractures of the calcaneum. J Trauma. 1979 Dec;19(12):939-43. 40. Kitaoka HB, Schaap EJ, Chao EY, An KN. Displaced intra-articular fractures of the calcaneus treated non-operatively. Clinical results and analysis of motion and ground-reaction and temporal forces. J Bone Joint Surg Am. 1994 Oct;76(10): 1531-40. 41. Madeley NJ, Wing KJ, Topliss C, Penner MJ, Glazebrook MA, Younger AS. Responsiveness and validity of the SF-36, Ankle Osteoarthritis Scale, AOFAS Ankle Hindfoot Score, and Foot Function Index in end stage ankle arthritis. Foot Ankle Int. 2012 Jan;33(1):57-63. 42. Moher D, Hopewell S, Schulz KF, Montori V, Gøtzsche PC, Devereaux PJ, Elbourne D, Egger M, Altman DG. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. BMJ. 2010 Mar 23;340: c869.
BY
T HE J OURNAL
OF
B ONE
AND J OINT
S URGERY, I NCORPORATED
Displaced Intra-Articular Calcaneal Fractures Treated in a Minimally Invasive Fashion Longitudinal Approach Versus Sinus Tarsi Approach Tao Zhang, MD*, Yanling Su, MD, MPH*, Wei Chen, MD, PhD, Qi Zhang, MD, PhD, Zhanpo Wu, MD, PhD, and Yingze Zhang, MD Investigation performed at the Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, Republic of China
Background: The optimal treatment for displaced intra-articular fractures of the calcaneus remains controversial. This study aims to assess the clinical outcomes of a minimally invasive longitudinal approach compared with the sinus tarsi approach in the surgical treatment of these fractures. Methods: Patients with a displaced intra-articular fracture of the calcaneus who were admitted to the trauma center of our hospital from September 2009 through April 2010 were randomly assigned to treatment using one of these two surgical techniques. All patients underwent the same standardized postoperative rehabilitation protocol. Functional outcome was assessed by using the American Orthopaedic Foot & Ankle Society scores. Linear regression analysis was performed to identify the potential influencing factors for functional outcomes. Results: One hundred and sixty-seven patients who met the inclusion criteria were included in the study. Thirty-seven patients were lost to follow-up for various reasons, and the remaining 130 patients were followed for an average of twentyseven months. Sixty-nine fractures in sixty-three patients were treated using a minimally invasive longitudinal approach (the MILA group), and seventy-two feet in sixty-seven patients were treated with a sinus tarsi approach (the STA group). The two groups were comparable in terms of age, sex, fracture type, and time from injury to operation. The operative time in the MILA group was significantly shorter than that in STA group (p < 0.05). Wound-healing complications were 2.9% in the MILA group and 12.5% in the STA group. The average time to the start of progressive weight-bearing exercise was 5.3 weeks in the MILA group and 5.6 weeks in the STA group (p > 0.05). The good and excellent results in the two groups were comparable for the Sanders type-II and III calcaneal fractures (p > 0.05), but the good to excellent rate in the STA group was significantly higher for the Sanders type-IV fractures (p < 0.05). Linear regression analysis showed that surgical technique, Sanders classification, and the time to the start of weight-bearing activity have a significant influence on functional outcomes. Conclusions: Outcomes are similar for the minimally invasive longitudinal and sinus tarsi surgical approaches in the treatment of Sanders type-II and III displaced intra-articular fractures of the calcaneus, with the benefit of a lower complication rate and shorter operative time for the minimally invasive technique. For Sanders type-IV fractures, however, the sinus tarsi approach appears to be the treatment of choice. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. It was also reviewed by an expert in methodology and statistics. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
T
he optimal surgical approach for the accurate reduction of a displaced intra-articular fracture of the calcaneus, while minimizing wound-related complications, remains
controversial. One of the most commonly used methods in clinical practice is open reduction and internal fixation through an extended lateral approach1,2. Unfortunately, the wound
*Tao Zhang, MD, and Yanling Su, MD, MPH, contributed equally to the preparation of this article. Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
J Bone Joint Surg Am. 2014;96:302-9
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TABLE I Operative Information on the Patients in the Two Groups General Information
MILA Group*
STA Group*
P Value
Age† (yr)
39.8 ± 11.9
41.7 ± 10.0
0.216
Sex Male Female
56 7
58 9
Sanders classification (no. of feet) Type II Type III Type IV
32 23 14
29 27 16
Injured foot Unilateral Bilateral
57 6
62 5
5.8 ± 1.8
6.3 ± 1.8
0.051
45.9 ± 18.2
61.9 ± 15.3
0.001
0.687
0.764
0.673
Time from injury to operation† (days) Operative time† (min)
*MILA = minimally invasive longitudinal approach, and STA = sinus tarsi approach. †The values are given as the mean and the standard deviation.
complication rate has been reported to be as high as 30% in patients treated with this approach3,4. The soft-tissue envelope over the lateral wall of the hindfoot is particularly thin and vulnerable, potentially creating a high risk for wound-related complications5,6. Carr7 recommended minimally invasive approaches to treat displaced intra-articular calcaneal fractures, and various minimally invasive approaches7-12 have been introduced to minimize the wound complication rate. Some of these approaches have been effective in lowering the prevalence of wound-related complications5,13-18. The sinus tarsi approach has become one of the most frequently applied minimally invasive approaches because of its ability to provide adequate exposure for the posterior facet, the anterolateral fragment, and the lateral
wall. Wound complication rates with this approach have been reported to range from 0% to 15.4%12. In an effort to decrease the wound complication rate and shorten the operative time, we introduced, in 2004, a minimally invasive approach that features a small longitudinal lateral incision on the hindfoot and the use of a plate and compression bolts19. A large clinical study 20 carried out by our team found that the functional outcome after the minimally invasive longitudinal approach was as good as, if not better than, the traditional L-shaped extensile lateral approach with the benefit of a significantly lower complication rate. The aim of the present study was to compare the clinical outcomes of the widely used sinus tarsi approach with those of the minimally invasive longitudinal approach.
TABLE II Soft-Tissue Complications MILA Group* (N = 69) Complications
STA Group* (N = 72)
No. of Feet
Percentage
No. of Feet
Percentage
P Value
Wound-healing complications Superficial infection Deep infection Wound-edge necrosis
2 2 0 0
2.9
9 5 2 2
12.5
0.034
Sural nerve injury
1
1.5
3
4.2
–
Medial plantar nerve injury and restricted movement of flexor hallucis longus tendon
4
5.8
3
4.2
–
Severe defect with plate removal
2
2.9
3
4.2
–
Total
7
10.1
13
18.1
*MILA = minimally invasive longitudinal approach, and STA = sinus tarsi approach.
0.178
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treat a unilateral fracture or were placed in the prone position for bilateral fractures. The reduction and fixation technique using the minimally invasive 19,20 longitudinal approach has been described in detail in our previous studies . A 3.5-cm longitudinal incision is made over the posterior part of the lateral aspect of the hindfoot along the lateral border of the Achilles tendon (Fig. 1). Steinmann pins are used to restore the B¨ohler angle and posterior articular facet by percutaneous leverage. The fracture is fixed with an anatomical plate and two, three, or four compression bolts in a minimally invasive manner. The quality of the reduction is assessed intraoperatively with use of a C-arm fluoroscopic image intensifier. 12 The standard sinus tarsi approach to the calcaneus provides direct exposure for reduction of the posterior facet. The anatomical plate and compression bolts can be applied by inserting them subcutaneously (Fig. 2).
Postoperative Management and Follow-up
Fig. 1
A 3.5-cm longitudinal incision is made over the posterior part of the lateral aspect of the hindfoot along the lateral border of the Achilles tendon. The anatomical plate is introduced through the incision in a subcutaneous tunnel. The red line indicates the minimally invasive longitudinal approach. 1 = the superficial peroneal nerve, and 2 = the sural nerve.
Materials and Methods
P
atients with a displaced intra-articular calcaneal fracture, who were admitted to the trauma center of our hospital from September 2009 through April 2010, were randomly assigned to two groups for surgical treatment with either a minimally invasive longitudinal approach (the MILA group) or a sinus tarsi approach (the STA group). One researcher on our team who was not involved in the clinical treatment of patients used a random-number table to divide the patients into the two groups. The six senior surgeons on our team, all with more than ten years of clinical experience in treating displaced intraarticular calcaneal fractures, were familiar with both minimally invasive approaches. The surgeons were numbered from 1 to 6 and were assigned to perform the operations using either the minimally invasive longitudinal approach or the sinus tarsi approach in turn. This assignment mechanism provides each surgeon with similar opportunities to perform both approaches and subsequently minimizes the bias among different surgeons. The inclusion criteria were a displaced intra-articular calcaneal fracture, an age of eighteen years or older, and no polytrauma of the ipsilateral lower limb at the time of admission. Patients who had severe medical ailments or declined to accept the assigned treatment algorithm were excluded. All calcaneal fractures in both groups were fixed with the same implants, that is, anatomic plates and multiple compression bolts. The Ethical Board Review of the Third Hospital of Hebei Medical University (Shijiazhuang, Hebei, China) approved the conduct of the study, and each patient provided informed consent. The study was performed in accordance with the ethical standards of the Declaration of Helsinki of 1964. The study was registered in the registry of the Health Department of Hebei Province (05276403D-16).
CTscans and radiographs of the injured feet were made right after the operation to evaluate the quality of the reduction and the fixation of the fracture (see Appendix), and the most obvious displacement of the posterior facet was measured on the sagittal and coronal views of the CT images. Non-weightbearing exercises, including extension and plantar flexion of the toes and ankle, were encouraged as soon as the pain could be tolerated. Crutch-assisted walking was allowed two or three days postoperatively. Partial weight-bearing was encouraged to begin at four weeks after the operation and to progress gradually. Full weight-bearing was allowed with evidence of osseous union on the radiographs, generally at three months postoperatively. The patients were seen for follow-up at six weeks and at three, six, and twelve months after the operation and then yearly thereafter. A physical examination was performed, and lateral and axial radiographs of the injured foot were made at each follow-up evaluation. The B¨ohler angle was measured on the lateral radiographs of the calcaneus. A CT scan was performed at the time of the three-month follow-up. Hardware was removed routinely for each patient at twelve months unless the patient had indications for earlier hardware removal.
Functional Outcome Evaluation The functional outcomes were evaluated according to the American Ortho21 paedic Foot & Ankle Society (AOFAS) hindfoot scores at the time of the twenty-four-month follow-up. The functional outcomes and complications were assessed and recorded by an independent surgeon who was blinded to the study design and the group assignment.
Preoperative Management All patients underwent preoperative calcaneal lateral and axial radiographs and a computed tomography (CT) scan of the injured foot. The injury severity was graded according to the Sanders classification on the basis of the CT scan findings. When the swelling subsided and wrinkles appeared on the hindfoot, the fractures were treated surgically. Fig. 2
Surgical Procedure
The sinus tarsi approach permits direct visualization of the articular sur-
Under either epidural or spinal anesthesia, patients were placed in the lateral decubitus position with the lateral malleolus of the affected foot uppermost to
face, and the anatomical plate can be applied through the horizontal incision (red line). 1 = the superficial peroneal nerve, and 2 = the sural nerve.
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Fig. 3
CONSORT
42
(Consolidated Standards of Reporting Trials) flow diagram.
Statistical Analysis On the basis of the functional outcomes of a preliminary study, a total sample size of not less than 165 patients was thought to be required to perform the statistical analysis. Continuous variables with non-normal distribution were analyzed with the Mann-Whitney U test. The non-paired t test was used to compare variables with a normal distribution. Categorical data were statistically analyzed by means of a chi-square test or Fisher exact test (n < 40 or t < 1). Four factors that may influence the functional outcome of displaced intra-articular calcaneal fractures were selected for evaluation: patient age, surgical technique (the minimally invasive longitudinal approach or the sinus tarsi approach), Sanders classification, and the time to the start of weight-bearing activity. Multinomial linear regression was used to analyze the relationship between functional recovery and these four factors. The categorical variables of surgical techniques, that is, the sinus tarsi approach and the minimally invasive longitudinal approach, were assigned a value of 0 and 1, respectively; and Sanders type-II, III, and IV fractures were assigned a value of 2, 3, and 4, respectively. A p value of 0.05). During subsequent measurements of the B¨ohler angle, no significant change was observed. According to the immediate postoperative CT scan, five of the sixty-nine fractures in the MILA group had articular incongruity of >3 mm and all five were Sanders type IV, while all seventy-two fractures in the STA group were reduced with 0.05). Patients in the STA group had better outcomes on all of the four subjective variables than patients in the MILA group. However, the two groups were only significantly different with regard to the variable of walking surface in the AOFAS scoring system (see Appendix). Of the patients who achieved good or excellent results in the MILA group, thirty-two had a type-II fracture; twenty-one, a type-III fracture; and two, a type-IV fracture. Of the patients who achieved good or excellent results in the STA group, twentynine had a type-II fracture; twenty-five, a type-III fracture; and nine, a type-IV fracture. Patients with Sanders type-II or III fractures in both groups had similar function outcomes (p = 1.000) (Table IV). However, for Sanders type-IV fractures, the good to excellent rate in the STA group was significantly higher than that in the MILA group (56.3% versus 14.3%; p < 0.05). Multinomial Linear Regression Analysis The multinomial linear regression analysis identified significant influencing factors for functional outcomes (F = 51.72,
p < 0.05). Three factors, including surgical technique, the Sanders classification, and the time to start weight-bearing activity, were found to be associated with the functional outcome (p < 0.05 for all; Table V). Discussion alcaneal fractures account for 2% of all fractures, and 80% to 90% of those fractures involve young adults22. As some patients who are treated nonoperatively for displaced intraarticular calcaneal fractures are unable to return to their original occupations or even completely lose the ability to work because of severe residual disability 23, surgical treatment has been recommended. However, the high complication rate presents challenges to the orthopaedic surgeon. The prevalence of wound-related complications after surgical treatment of calcaneal fractures has been reported to range from 7.57% to 32.8%3,24-26, and the neurovascular injury rate has been reported to range from 9.1% to 25%24,25,27.Various minimally invasive approaches have been developed to reduce the wound-related complication rates. Among them, the sinus tarsi approach has become one of the more popular minimally invasive methods as it can provide direct visualization of the posterior articular facet and has fewer soft-tissue-related complications12,28. Schepers reported an average wound complication rate of 4.8% (range, 0% to 15.4%) for patients treated with use of the sinus tarsi approach12. In 2004, we developed the minimally invasive longitudinal approach. This method has proven to be quite effective in treating displaced intra-articular calcaneal fractures compared with the open technique19,20. As part of our ongoing efforts to assess the clinical effectiveness of the minimally invasive longitudinal approach in the treatment of calcaneal fractures, we designed this study to compare the functional outcomes of the minimally invasive longitudinal approach with those of the sinus tarsi approach, using the AOFAS score29. The multinomial linear regression analysis showed that posterior facet displacement was associated with the functional outcome of calcaneal fractures. The Sanders classification can accurately reflect the severity of calcaneal fractures and the displacement of the posterior facet, which is one of the most important factors affecting the functional outcomes. Buckley et al.2 suggested that comminuted fractures were associated with a higher risk of poor outcomes regardless of the treatment method. The regression analysis also showed that the surgical
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method can affect the functional outcome. Using the minimally invasive longitudinal approach to treat all types of calcaneal fractures carries a risk of inadequate joint reconstruction. Biomechanical studies with pressure-sensitive films have revealed that even a minor residual step-off of the posterior facet may lead to a significant load shift within the subtalar joint30 and have an adverse effect on functional outcome31-33. According to the radiographic data, patients with Sanders type-II and III fractures in both groups had similar fracture reduction quality. However, for type-IV fractures or comminuted joint depression fractures, it appears that the sinus tarsi approach can yield a clearly better reduction of the articular surface than the minimally invasive longitudinal approach. The difference in the quality of articular reduction between the two groups may contribute to different functional outcomes. The analysis of the AOFAS scores according to the Sanders classification demonstrated no significant difference between the two approaches with regard to functional recovery for Sanders type-II and III calcaneal fractures. For Sanders type-IV fractures, however, the sinus tarsi approach can yield better functional outcomes than the minimally invasive longitudinal approach. The regression analysis showed that early weight-bearing activity, as part of the postoperative protocol, may affect the clinical outcomes. Clinical studies have also shown that patients with early postoperative weight-bearing activity may have better functional outcomes34,35. If reliable fixation can be achieved, then the earlier that weight-bearing activity is started, the better the functional outcomes that can be attained. In our study, the anatomic plate and compression bolts provided rigid fixation of the calcaneal fractures, which enabled partial weight-bearing as early as about four weeks after surgery when the pain had subsided. In contrast, the recommended amount of time for non-weight-bearing after other surgical methods has been reported to range from eight to ten weeks36. Pozo et al.37 reported that weight-bearing can lead to molding of the articular surface, which will help to restore the congruity of the subtalar joint. Our radiographic evaluation revealed some decreased articular step-off of the posterior facet in both groups after three months of weight-bearing. In addition, patients with prolonged non-weight-bearing usually develop osteoporosis and joint stiffness34, which is associated with a poor outcome in these fractures. Kingwell et al.38 reported that the range of subtalar motion after the surgery can directly affect patient satisfaction. In addition, a shortened non-weight-bearing time may postpone the development of posttraumatic subtalar arthritis20,35. In the current study, evidence of subtalar arthritis was observed on the CT scan of eight feet (5.6%), less than that reported in previous studies (6.25% to 12.90%)4,25,32,37,39,40. The wound-healing complication rate was 2.9% in the MILA group, significantly lower than the 12.5% rate in the STA
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group. The minimized disturbance to the blood supply of the lateral aspect of the hindfoot17 and the significantly shorter operative time in the MILA group may contribute to the lower rate of superficial wound complications as well as wound-edge necrosis. Furthermore, the minimally invasive longitudinal approach has a low risk of sural nerve injury. The course of the incision in the minimally invasive longitudinal approach is parallel to the proximal part of the sural nerve, and inserting the anatomic plate transversely can avoid injury to the distal part of the sural nerve. While the nuts used in the current study were of smaller size than in the past, care should be taken as their use still may lead to medial plantar nerve injury, skin irritation, and flexor hallucis longus tendon restriction. There are some limitations of the current study. First, 22.2% of the patients were either lost to follow-up or declined to participate in postoperative follow-up, which lowered the total sample size and weakened the statistical power of the final results. In addition, the AOFAS score, as the main outcome measure, has its own limitations, which may compromise the results. It has been criticized for its mathematical shortcomings, and the reliability of the score has yet to be proven41. Another limitation is that the two limbs in an individual should not be considered to be independent. However, we did not exclude the patients with bilateral calcaneal fractures, which may also be considered a limitation of the study design. Finally, the quantified data on the fracture reduction were not specifically analyzed. Appendix A table showing a comparison of the postoperative AOFAS scores and figures demonstrating the radiographs and CT scans of a calcaneal fracture in a thirty-three-year-old man are available with the online version of this article as a data supplement at jbjs.org. n
Tao Zhang, MD Yanling Su, MD, MPH Wei Chen, MD, PhD Qi Zhang, MD, PhD Zhanpo Wu, MD, PhD Yingze Zhang, MD Department of Orthopaedic Surgery, Third Hospital of Hebei Medical University, 139 Ziqiang Road, Shijiazhuang 050051, Hebei, Republic of China. E-mail address for T. Zhang: [email protected]. E-mail address for Y. Su: [email protected]. E-mail address for W. Chen: [email protected]. E-mail address for Q. Zhang: [email protected]. E-mail address for Z. Wu: [email protected]. E-mail address for Y. Zhang: [email protected].
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