The Journal of Arthroplasty xxx (2014) xxx–xxx
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The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips Junfeng Zhu, PhD, MD, Chao Shen, PhD, MD, Xiaodong Chen, PhD, MD 1, Yiming Cui, MD, Jianping Peng, PhD, MD, Guiquan Cai, PhD, MD Department of Orthopaedics, Xinhua Hospital, Affiliated to Shanghai Jiaotong University Medical School, Shanghai China
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Article history: Received 15 September 2014 Accepted 4 November 2014 Available online xxxx Keywords: high dislocation Crowe type IV subtrochanteric femoral osteotomy total hip arthroplasty cementless stem
a b s t r a c t Conventional stems may be unsuitable for hypoplastic femurs associated with severe dysplasia, meanwhile, custom-made or modular stems in total hip arthroplasty are often complex and expensive. This series included 21 Crowe type IV dysplastic hips in which a non-modular cementless conical stem was implanted with transverse subtrochanteric femoral osteotomy. Follow up averaged 40 months. Twenty hips survived with mean Harris hip score improved from 52 to 90. One hip failed for stem loosening. The average leg lengthening was 3.8 cm with transient sciatic nerve palsy occurring in three hips. Femoral offset averaged 3.3 cm postoperatively. The nonmodular conical stem not only obviated the complexities, high medical cost and potential risk at the neckstem interface associated with stem modularity, but also simplified surgical technique. © 2014 Elsevier Inc. All rights reserved.
Total hip arthroplasty (THA) in high dislocated hips presents specific difficulties including restoration of the normal hip center, correction of excessive femoral anteversion and fitting the prosthesis in a narrow and straight medullary canal [1,2]. The use of a conventional stem may be impossible in hypoplastic femurs because the proximal femoral anatomy often progressively worsens in line with the grade of dysplasia [1]. For easier control of neck anteversion, custom-made components, tapered prostheses as well as dual modular stems have been recommended in some studies [3,4]. Either custom-made or modular stems are technically challenging and expensive [3–5]. Although additional junctions of modular stems offer many advantages, they have potential risks for neck-body complications and increasing amounts of metal debris from neck-stem or sleeve-stem interface [5]. From our perspective, cementless tapered prostheses are preferred over cemented stems because of the relatively young age of patients and concurrent subtrochanteric osteotomy. However, few studies have reported on non-modular conical stems for high dislocated hip treatment even though the results of this prostheses in moderate hip dysplasia have been encouraging [6,7]. The Wagner Cone Prosthesis Hip Stem (Zimmer) is a non-modular conical stem with eight longitudinal sharp ribs. For better rotational stability and easier correction of neck antevertion, the cementless Wagner stem has been established as an appropriate and inexpensive solution for Crowe type I and II dysplastic hips [6–9]. However, few cases of Crowe type IV or Crowe type III dysplastic hips were reported in these studies. The increased soft tissue
contracture and bone deformity in severely dislocated hips presents additional technical challenges including femoral osteotomy, stem fixation and soft tissue balancing. The clinical results of Wagner stem in high dysplastic hips (Crowe type IV) remain unclear since the rates of failure and complications increased with the grades of dysplasia [10,11]. The aim of this study is to define the short-term radiographic and clinical outcomes, and complications of Crowe type IV dysplastic hips treated with the non-modular cementless conical stem.
The Conflict of Interest statement associated with this article can be found at http:// dx.doi.org/10.1016/j.arth.2014.11.002. Reprint requests: Xiaodong Chen, Department of Orthopaedics, Xinhua Hospital, Shanghai Jiaotong University Medical School, Building 8, No. 1665, Kongjiang Road, Shanghai 200092 China. 1 Dr. Junfeng Zhu and Dr. Chao Shen contributed equally to this paper.
A distally extended posterolateral approach was performed by one senior surgeon (X. Chen) to expose the hip joint and proximal femur in all cases. After capsulotomy, the true acetabulum was identified by removing the soft tissue within it. A Trilogy Acetabular System
Patients and Methods A consecutive series of 21 hips in 20 patients who were diagnosed as hip dysplasia of Crowe type IV [12] was retrospectively identified out of a total THA cohort of 1226(1271 hips) patients at our institution. Eighteen female (19 hips) and two male patients were identified and investigated based on the ethical standards of the committee on human experimentation of our institution. The patients' age ranged from 21 to 77 years (mean 36 years) at the time of surgery between March 2009 and March 2012. The average body-mass index was 21.8 (range, 18.2–26.6). The operative time ranged from 2 to 3.5 hours (mean 2.5 hours). Four hips (19%) had a total of five surgical procedures prior to the index THA including open reduction (four hips) and varusproducing proximal femoral osteotomy (one hip). Surgical Technique
http://dx.doi.org/10.1016/j.arth.2014.11.002 0883-5403/© 2014 Elsevier Inc. All rights reserved.
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
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J. Zhu et al. / The Journal of Arthroplasty xxx (2014) xxx–xxx
(Zimmer, Warsaw, IN, USA) was placed at the level of original acetabulum or a slightly elevated position without lateralization. Moderate medialization of the cementless cup without perforating the inner cortex was performed in some cases. If the original acetabulum bone stock was deficient, bulk autografts from the resected femoral head were fixed with screws to provide acetabular component coverage. The acetabular component was fixed with screws in all cases. After the implantation of the acetabular component, the femur was prepared as previously described [13]. The medullary cavity was gradually widened with a tapered reamer. The extension was complete when the reamer received powerful frictional resistance. A subtrochanteric shortening osteotomy [14] was performed beneath the lesser trochanter to avoid excessive stretching of the sciatic nerve. After hip reduction with a femoral trial stem only seated in the proximal fragment, the length of bone resection was decided according to the overlapping of the femoral segments. After the shortening osteotomy, two femoral fragments were held face to face by two bone holding forceps and reamed again. For the proper restoration of femoral offset, the scheduled conical stem was implanted distally and connected to a longer femoral head if necessary. Prophylactic cable fixation was used before the insertion of the uncemented Wagner Cone Prosthesis Hip Stem (Zimmer, Warsaw, IN, USA) to prevent iatrogenic splitting of the femur. Rotation of the trial stem was initially estimated in 15°–20° of anteversion relative to the lower leg bent at a right-angle. The anteversion of implanted cone stems could be slightly increased or decreased based on the hip stability after reduction. The wear bearing materials of this cohort consisted of ceramic-on-ceramic in 19 hips and metal-on-poly in 2 hips. The osteotomy site was grafted with cancellous bone from the femoral head. Patients were hospitalized in an average of 7.7 days (range, 6–11 days). Partial weight bearing was encouraged at 3–6 weeks postoperatively. Twelve weeks later, full weight bearing was usually allowed if osseous healing was positive at the osteotomy sites.
Fig. 1. Radiographs are shown of a 59-year-old woman with Crowe type IV dysplastic right hip. (A) The preoperative femoral off-set was 2.3 cm. The preoperative leg length discrepancy (LLD) was 5.2 cm and the preoperative Harris hip score was 58. (B) At 3-month follow up, bone union was detected on the lateral half of the osteotomy site. The postoperative femoral off-set was 3.4 cm and leg lengthening was 3.7 cm. The postoperative LLD was 14 mm. (C) At 1-year follow up, the osteotomy site was completely healed. The postoperative Harris hip score was 97. (D) No subsidence or radiolucent lines around the prosthesis was found at 4-year follow up. The amount of radiographic leg lengthening was measured by subtracting the amount of intraoperative femoral resection from the distance between the top of the greater trochanter preoperatively and postoperatively on radiographs [16]. LLD indicated the length discrepancy of lower extremities which was measured with a tape by measuring the distance between the anterior superior iliac spine and the medial malleolus [15].
Clinical and Radiographic Evaluation Clinical results were evaluated with Harris Hip Score (HHS) and leg length discrepancy (LLD) preoperatively, at 6 months and 1 year postoperatively, and then yearly until the last follow-up. LLD indicated the length discrepancy of lower extremities which was measured with a tape by measuring the distance between the anterior superior iliac spine and the medial malleolus [15]. Clinical failure was defined as the need for revision surgery. Anteroposterior and false profile lateral radiographs were made at each follow-up visit. Radiographic evaluation was performed by one surgeon (J. Zhu) including femoral off-set, leg lengthening, loosening signs and bone union of femoral osteotomy. The femoral off-set was defined by measuring the distance on radiographs between the femoral axis and the femoral head center. The amount of radiographic leg lengthening was measured by subtracting the amount of intraoperative femoral resection from the distance between the top of the greater trochanter preoperatively and postoperatively on radiographs [16]. The stability of the femoral components was assessed radiographically as previously described [17]. Stable fixation by bone ingrowth was defined as no subsidence or radiolucent lines around the prosthesis. Provided consolidation presented across the osteotomy sites, osseous healing was determined.
of these patients postoperatively improved (Fig. 1 and Table 1). Femoral shortening subtrochanteric osteotomy was performed with an average femoral resection of 1.5 cm (range 1.0–2.5 cm). Limp that characterized by excessive lateral trunk movement over the affected hip, was postoperatively corrected or improved in 20 hips, based on a function of the lateral head motion [18]. Twenty hips survived at the last follow-up without observed subsidence. One hip was dislocated in a 77 years old lady and manipulated with closed reduction at first postoperative month (Fig. 2). The same hip was revised at 6 months follow-up due to early stem loosening between the stem and distal femoral fragment. No infection was found following the surgery in this cohort. Postoperative sciatic nerve palsy occurred in three hips with leg lengthening of 4.5 cm, 5.5 cm and 6.8 cm. Two cases of nerve palsy (3/5) disappeared in 3 months. The other case which had the maximal leg lengthening of 6.8 cm in this series improved from 2/5 to 4/5 after one year. All acetabular implants survived at last follow up without any complication. Nonunion of the femoral osteotomy site was recorded in the previous hip which was revised at 6 months follow up due to early stem loosening. The average time to bone union for the other 20 hips was 5 months (range 3–9 months). One case of delayed union at the femoral osteotomy site was found and healed at 9-month follow-up.
Statistical Analysis Preoperative and postoperative HHS scores, LLD and radiographic evidences were compared using t test. Significance was determined at a P value of b0.05. Results The average follow-up of total 21 hips lasted 40 months (range, 24–60 months). The average HHS score, LLD and radiographic evaluation
Table 1 Preoperative and Postoperative Radiographic and Clinical Results.
Harris hip score Leg discrepancy (cm) Femoral off-set (cm) Leg lengthening (cm)
n
Preoperative Value
Postoperative Value
P Value
21 20 21 21
52.4 ± 6.8(35–63) 4.7 ± 1.1 (2–7) 1.9 ± 0.5 (1–2.6)
90.5 1.2 3.3 3.8
b0.001 b0.001 b0.001
± ± ± ±
15.1 (26–97) 0.4 (0–2) 0.4 (2.8–4) 0.9 (3–6.8)
Values are expressed as mean ± standard deviation with range in parentheses.
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
J. Zhu et al. / The Journal of Arthroplasty xxx (2014) xxx–xxx
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Fig. 2. Radiographs are shown of a 77-year-old woman with Crowe type IV dysplastic right hip. (A) The preoperative leg length discrepancy was 6 cm and the preoperative Harris hip score was 35. (B–D) Hip stability was reconstructed by primary hip replacement with subtrochanteric shortening osteotomy. However, hip dislocation happened at first postoperative month and manipulated with close reduction. (E) At 6-month follow up, stem loosening was clearly detected, whereas osseous healing wasn't completed at the osteotomy site. (F) The hip was revised with a longer cementless stem and a locking plate. During the surgery, prosthesis loosening was identified between the stem and distal femoral fragment. However, the conical stem was still stable in the proximal femoral fragment with small amount of osteointegration.
Discussion Good clinical results and meticulous surgical technique of nonmodular cementless prostheses, such as the Wagner Cone Stem, were reported in total hip arthroplasty for Crowe type I and II dysplastic hips [6–9]. However, Crowe type IV dysplastic hips present the greatest degree of anatomical abnormality [1]. The restoration of hip rotation center with the common need for concurrent femoral osteotomies in Crowe type IV dysplastic hips can lead to technical difficulties in ensuring femoral deformity correction and stem stability. To our knowledge, our report represents that first study of hip arthroplasty with the nonmodular cementless Wagner stem for treating Crowe type IV dysplastic hips, with femoral shortening subtrochanteric osteotomy. The position of acetabular components is optimal when reconstructed in a normal anatomic position [19]. High or superolateral placement of the acetabular components is avoided by many surgeons because an unfavorable biomechanical environment could lead to greater joint contact forces, less mechanical advantage of the abductors, and higher rates of acetabular component loosening [16,20]. Slight elevation of the hip center without lateralization may be acceptable since a recent report of 30 hips treated with this technique showed no evidence of loosening at an average of 15.2 year follow-up [21]. Moderate medialization of the acetabular components could be an alternative solution in some cases due to its known biomechanical advantage and clinical durability [20,22]. However, a small cup or cotyloplasty technique was not advocated in this study. Considering the relatively young age of these patients and the desire for bone stock preservation for potential hip revision arthroplasty, ceramic bearing and structural acetabular autograft was preferred in most cases. After the anatomic placement of acetabular components, femoral shortening osteotomy was needed to overcome the excessive stretching of the sciatic nerve. Different techniques of femoral shortening including proximal, diaphyseal and distal osteotomies have been described [23–25]. These techniques were difficult to be compared because of the differences in the types of hips, ages of patients and follow-up periods under investigation [26]. Short or medium term results of Crowe IV hips treated with subtrochanteric shortening osteotomy showed excellent healing rates of the osteotomy, ranging from 93% to 100% [24,27].
Hence, transverse subtrochanteric osteotomy was suggested in this study. Only one case (4.8%) of nonunion was found at the osteotomy site following postoperative dislocation and early loosening between the stem and distal femoral fragment. An oblique, step-cut or chevron osteotomy may increase bony apposition and torsional stability [28–30]. However, these complex geometrical osteotomy techniques require detailed preoperative planning and could prevent intraoperative adjustment. On basis of the press-fit between the stem and the femoral bone cortex, the nonmodular conical stem obviated the complexities and potential risks which were indicated at the metaphyseal neck-stem interface of modular stems. The instability and early loosening of the stem were prevented in Crowe type I and II dysplastic hips [6–9] due to eight longitudinal sharp ribs of the tapered stem, which allowed adequate press-fit and good orientation of the implant in a dysplastic femur. In this study, after the transverse subtrochanteric osteotomy, the press-fit in a severely dysplastic femur was required in both proximal and distal femoral fragments. To obtain enough length of engagement between the stem and distal femoral fragment, the site of subtrochanteric osteotomy in this study was suggested at a level close to the less trochanter. Additionally, the surface area of the conical stem was greater in the proximal than the distal part. With a continuous surface press-fit, a uniform load transfer per unit of area can be assumed [8]. Therefore, the load distribution in the conical stem was greater in the proximal region which would benefit osteointegration of the stem and reduce the risk of nonunion at osteotomy site. Radiographic follow-up showed great osteointegration of the stem in the proximal region of dysplastic femurs [8]. The average time of 5 months for bone union at osteotomy site in this study was comparable to previous results [16,30]. Several factors related to bone union at the osteotomy site. Firstly, aggressive reaming in the femoral canal resulted in a release of bone marrow cells and degeneration of the endosteum, both of which had the potential to form new bone at the osteotomy site [31]. Furthermore, the preparation of osteotomy sites by removing periosteum circumferentially, as well as the prevention of perioperative femoral fracture by using cerclage wiring around the outer surface of the cortex could injury the osteoblastic activity of the periosteum. Moreover, the stability of the interface between two femoral osteotomy fragments was emphasized. After shortening osteotomy and derotation of the proximal femoral fragment,
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
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it was difficult to keep the congruency between proximal and distal canal diameters. To achieve such stability, osteosynthesis was suggested in this situation [32]. The only one case of nonunion in this study was revised at six-month follow-up due to stem loosening. This 77 years old lady got dislocation 1 month after surgery as she over flexed her hip. Closed reduction was manipulated under general anesthesia. Because of high dislocated hip (Fig. 2C), relatively high traction force was manipulated on her low extremity during reduction. During the revision surgery, the conical stem was still found stable in the proximal femoral fragment with small amounts of osteointegration. A previous dislocation and following closed reduction could compromise the press-fit between the stem and distal femoral fragment, because the uncemented conical stem is easy to disengage under traction. Therefore, the movement of stem in distal femoral fragment and the instability between the two femoral osteotomy fragments were introduced, which accounted for the bone nonunion and early stem loosening in this case. The short-term functional outcomes greatly improved in the 20 hips of this study. The increased HHS score and improved limp of these hips mostly resulted from an ease of preoperative hip pain, leg lengthening and the restoration of femoral offset. The average leg lengthening of 3.8 cm in this series was safe from the risk of post-operative nerve palsy [33]. The mean postoperative femoral offset of 3.3 cm in this series was comparable to 3.4 cm on normal population [34,35]. The increased postoperative femoral offset restored abductor muscles lever arm, whereas it reduced joint reaction forces which minimized the rate of bearing wear [3]. Recently, dual modular prostheses were preferred for the advantage of proper restoration of femoral offset. A nonmodular stem, however, was still effective to properly restore femoral offset in this study by distally implanting the conical stem and using a longer femoral head. This study has several limitations. Firstly, there was no broad consensus on the definition of modular and non-modular stem. In this study, the Wagner Cone prosthesis was identified as a nonmodular stem as other femoral stem which was monoblock or only had a neck-head junction [5,36]. Secondly, the duration of follow-ups in this study has been short since the new version of Wagner Cone stem was introduced to the market in 2006. Two of twenty patients didn't return to our clinic at the last follow up. We considered, however, it was reasonable to include the two patients, because they were interviewed by telephone and still satisfied with the involved hips. The third limitation is the relatively small number of patients. At the early stage of our practice, we were limited by both the learning curve and conservative patient selection. In summary, good survivorship and joint function were identified in Crowe type IV dysplastic hips treated with the uncemented conical stem. Compared with modular prostheses and custom-made prostheses, the non-modular conical stem obviated the complexities, high medical cost and potential risk at the neck-stem interface but also poses a challenging hip reconstruction. Acknowledgments The authors greatly value the writing assistance from Dr. John C. Clohisy from Washington University School of Medicine in St. Louis USA. The study was financially supported by National Natural Science Foundation of China (no. 81171705, 81101381 and 81101379), Shanghai Municipal Commission of Health and Family Planning Foundation (no. 20134002) and Research Foundation of Shanghai Jiaotong University Medical School (no. YZ1002). References 1. Noble PC, Kamaric E, Sugano N, et al. Three-dimensional shape of the dysplastic femur: implications for THR. Clin Orthop Relat Res 2003;417:27. 2. Sugano N, Noble PC, Kamaric E, et al. The morphology of the femur in developmental dysplasia of the hip. J Bone Joint Surg (Br) 1998;80:711.
3. Traina F, De Fine M, Tassinari E, et al. Modular neck prostheses in DDH patients: 11-year results. J Orthop Sci 2011;16:14. 4. Benum P, Aamodt A. Uncemented custom femoral components in hip arthroplasty. A prospective clinical study of 191 hips followed for at least 7 years. Acta Orthop 2010; 81(4):427. 5. Srinivasan A, Jung E, Levine BR. Modularity of the femoral component in total hip arthroplasty. J Am Acad Orthop Surg 2012;20(4):214. 6. Claramunt RT, Marqués F, León A, et al. Total hip replacement with an uncemented Wagner cone stem for patients with congenital hip dysplasia. Int Orthop 2011;35 (12):1767. 7. Pak P, de Steiger R. Cone femoral prosthesis for osteoarthritis of the hip with femoral dysplasia. J Orthop Surg 2008;16(2):206. 8. Faldini C, Miscione MT, Chehrassan M, et al. Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up. J Orthop Traumatol 2011;12(4):213. 9. Faldini C, Nanni M, Leonetti D, et al. Total hip arthroplasty in developmental hip dysplasia using cementless tapered stem. Results after a minimum 10-year follow-up. Hip Int 2011;21(4):415. 10. Cameron HU, Botsford DJ, Park YS. Influence of the Crowe rating on the outcome of total hip arthroplasty in congenital hip dysplasia. J Arthroplasty 1996;11:582. 11. Chougle A, Hemmady MV, Hodgkinson JP. Severity of hip dysplasia and loosening of the socket in cemented total hip replacement. A long-term follow-up. J Bone Joint Surg (Br) 2005;87:16. 12. Crowe JF, Mani VJ, Ranawat CS. Total hip replacement in congenital dislocation and dysplasia of the hip. J Bone Joint Surg Am 1979;61:15. 13. Wagner H, Wagner M. Cone prosthesis for the hip joint. Arch Orthop Trauma Surg 2000;120(1–2):88. 14. Charity JA, Tsiridis E, Sheeraz A, et al. Treatment of Crowe IV high hip dysplasia with total hip replacement using the Exeter stem and shortening derotational subtrochanteric osteotomy. J Bone Joint Surg (Br) 2011;93(1):34. 15. Sabharwal S, Kumar A. Methods for assessing leg length discrepancy. Clin Orthop Relat Res 2008;466(12):2910. 16. Makita H, Inaba Y, Hirakawa K, et al. Results on total hip arthroplasties with femoral shortening for Crowe's group IV dislocated hips. J Arthroplasty 2007;22:32. 17. Gruen TA, McNeice GM, Amstutz HC. “Modes of failure” of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop Relat Res 1979;141:17. 18. Murray MP, Gore DR, Brewer BJ, et al. Comparison of Müller total hip replacement with and without trochanteric osteotomy. Acta Orthop Scand 1981;52:345. 19. Thillemann TM, Pedersen AB, Johnsen SP, et al. Implant survival after primary total hip arthroplasty due to childhood hip disorders: results from the Danish Hip Arthroplasty Registry. Acta Orthop 2008;79:769. 20. Murayama T, Ohnishi H, Okabe S, et al. 15-year comparison of cementless total hip arthroplasty with anatomical or high cup placement for Crowe I to III hip dysplasia. Orthopedics 2012;35(3):313. 21. Kaneuji A, Sugimori T, Ichiseki T, et al. Minimum ten-year results of a porous acetabular component for Crowe I to III hip dysplasia using an elevated hip center. J Arthroplasty 2009;24:187. 22. Heller MO, Schröder JH, Matziolis G, et al. Musculoskeletal load analysis. A biomechanical explanation for clinical results–and more? Orthopade 2007;36(188):190. 23. Koulouvaris P, Stafylas K, Sculco T, et al. Distal femoral shortening in total hip arthroplasty for complex primary hip reconstruction: a new surgical technique. J Arthroplasty 2008;23:992. 24. Krych AJ, Howard JL, Trousdale RT, et al. Total hip arthroplasty with shortening subtrochanteric osteotomy in Crowe type-IV developmental dysplasia. J Bone Joint Surg Am 2009;91:2213. 25. Macheras GA, Kateros K, Koutsostathis SD, et al. The Trabecular Metal Monoblock acetabular component in patients with congenital hip dislocation: a prospective study. J Bone Joint Surg (Br) 2010;92:624. 26. Hartofilakidis G, Babis GC, Georgiades G, et al. Trochanteric osteotomy in total hip replacement for congenital hip disease. J Bone Joint Surg (Br) 2011;93(5):601. 27. Bernasek TL, Haidukewych GJ, Gustke KA, et al. Total hip arthroplasty requiring subtrochanteric osteotomy for developmental hip dysplasia: 5- to 14-year results. J Arthroplasty 2007;22:145. 28. Huo MH, Zatorski LE, Keggi KJ. Oblique femoral osteotomy in cementless total hip arthroplasty. Prospective consecutive series with a 3-year minimum follow-up period. J Arthroplasty 1995;10:319. 29. Erdemli B, Yilmaz C, Atalar H, et al. Total hip arthroplasty in developmental high dislocation of the hip. J Arthroplasty 2005;20:1021. 30. Becker DA, Gustilo RB. Double-chevron subtrochanteric shortening derotational femoral osteotomy combined with total hip arthroplasty for the treatment of complete congenital dislocation of the hip in the adult: preliminary report and description of a new surgical technique. J Arthroplasty 1995;10:313. 31. Akiyama H, Kawanabe K, Yamamoto K, et al. Cemented total hip arthroplasty with subtrochanteric femoral shortening transverse osteotomy for severely dislocated hips: outcome with a 3- to 10-year follow-up period. J Orthop Sci 2011;16(3):270. 32. Minoda Y, Kadowaki T, Kim M. Total hip arthroplasty of dysplastic hip after previous Chiari pelvic osteotomy. Arch Orthop Trauma Surg 2006;126(6):394. 33. Edwards BN, Tullos HS, Noble PC. Contributory factors and etiology of sciatic nerve palsy in total hip arthroplasty. Clin Orthop 1987;218:136. 34. Sakalkale DP, Sharkey PF, Eng K, et al. Effect of femoral component offset on polyethylene wear in total hip arthroplasty. Clin Orthop Relat Res 2001:125. 35. Xue W, Dai K, Tang T, et al. Measurement and classification of geometric parameters in Chinese proximal femur. J Biomed Eng 2002;19(1):84. 36. Lombardi AV, Mallory TH, Fada RA, et al. Stem modularity: rarely necessary in primary total hip arthroplasty. Orthopedics 2002;25(12):1385.
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips Junfeng Zhu, PhD, MD, Chao Shen, PhD, MD, Xiaodong Chen, PhD, MD 1, Yiming Cui, MD, Jianping Peng, PhD, MD, Guiquan Cai, PhD, MD Department of Orthopaedics, Xinhua Hospital, Affiliated to Shanghai Jiaotong University Medical School, Shanghai China
a r t i c l e
i n f o
Article history: Received 15 September 2014 Accepted 4 November 2014 Available online xxxx Keywords: high dislocation Crowe type IV subtrochanteric femoral osteotomy total hip arthroplasty cementless stem
a b s t r a c t Conventional stems may be unsuitable for hypoplastic femurs associated with severe dysplasia, meanwhile, custom-made or modular stems in total hip arthroplasty are often complex and expensive. This series included 21 Crowe type IV dysplastic hips in which a non-modular cementless conical stem was implanted with transverse subtrochanteric femoral osteotomy. Follow up averaged 40 months. Twenty hips survived with mean Harris hip score improved from 52 to 90. One hip failed for stem loosening. The average leg lengthening was 3.8 cm with transient sciatic nerve palsy occurring in three hips. Femoral offset averaged 3.3 cm postoperatively. The nonmodular conical stem not only obviated the complexities, high medical cost and potential risk at the neckstem interface associated with stem modularity, but also simplified surgical technique. © 2014 Elsevier Inc. All rights reserved.
Total hip arthroplasty (THA) in high dislocated hips presents specific difficulties including restoration of the normal hip center, correction of excessive femoral anteversion and fitting the prosthesis in a narrow and straight medullary canal [1,2]. The use of a conventional stem may be impossible in hypoplastic femurs because the proximal femoral anatomy often progressively worsens in line with the grade of dysplasia [1]. For easier control of neck anteversion, custom-made components, tapered prostheses as well as dual modular stems have been recommended in some studies [3,4]. Either custom-made or modular stems are technically challenging and expensive [3–5]. Although additional junctions of modular stems offer many advantages, they have potential risks for neck-body complications and increasing amounts of metal debris from neck-stem or sleeve-stem interface [5]. From our perspective, cementless tapered prostheses are preferred over cemented stems because of the relatively young age of patients and concurrent subtrochanteric osteotomy. However, few studies have reported on non-modular conical stems for high dislocated hip treatment even though the results of this prostheses in moderate hip dysplasia have been encouraging [6,7]. The Wagner Cone Prosthesis Hip Stem (Zimmer) is a non-modular conical stem with eight longitudinal sharp ribs. For better rotational stability and easier correction of neck antevertion, the cementless Wagner stem has been established as an appropriate and inexpensive solution for Crowe type I and II dysplastic hips [6–9]. However, few cases of Crowe type IV or Crowe type III dysplastic hips were reported in these studies. The increased soft tissue
contracture and bone deformity in severely dislocated hips presents additional technical challenges including femoral osteotomy, stem fixation and soft tissue balancing. The clinical results of Wagner stem in high dysplastic hips (Crowe type IV) remain unclear since the rates of failure and complications increased with the grades of dysplasia [10,11]. The aim of this study is to define the short-term radiographic and clinical outcomes, and complications of Crowe type IV dysplastic hips treated with the non-modular cementless conical stem.
The Conflict of Interest statement associated with this article can be found at http:// dx.doi.org/10.1016/j.arth.2014.11.002. Reprint requests: Xiaodong Chen, Department of Orthopaedics, Xinhua Hospital, Shanghai Jiaotong University Medical School, Building 8, No. 1665, Kongjiang Road, Shanghai 200092 China. 1 Dr. Junfeng Zhu and Dr. Chao Shen contributed equally to this paper.
A distally extended posterolateral approach was performed by one senior surgeon (X. Chen) to expose the hip joint and proximal femur in all cases. After capsulotomy, the true acetabulum was identified by removing the soft tissue within it. A Trilogy Acetabular System
Patients and Methods A consecutive series of 21 hips in 20 patients who were diagnosed as hip dysplasia of Crowe type IV [12] was retrospectively identified out of a total THA cohort of 1226(1271 hips) patients at our institution. Eighteen female (19 hips) and two male patients were identified and investigated based on the ethical standards of the committee on human experimentation of our institution. The patients' age ranged from 21 to 77 years (mean 36 years) at the time of surgery between March 2009 and March 2012. The average body-mass index was 21.8 (range, 18.2–26.6). The operative time ranged from 2 to 3.5 hours (mean 2.5 hours). Four hips (19%) had a total of five surgical procedures prior to the index THA including open reduction (four hips) and varusproducing proximal femoral osteotomy (one hip). Surgical Technique
http://dx.doi.org/10.1016/j.arth.2014.11.002 0883-5403/© 2014 Elsevier Inc. All rights reserved.
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
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J. Zhu et al. / The Journal of Arthroplasty xxx (2014) xxx–xxx
(Zimmer, Warsaw, IN, USA) was placed at the level of original acetabulum or a slightly elevated position without lateralization. Moderate medialization of the cementless cup without perforating the inner cortex was performed in some cases. If the original acetabulum bone stock was deficient, bulk autografts from the resected femoral head were fixed with screws to provide acetabular component coverage. The acetabular component was fixed with screws in all cases. After the implantation of the acetabular component, the femur was prepared as previously described [13]. The medullary cavity was gradually widened with a tapered reamer. The extension was complete when the reamer received powerful frictional resistance. A subtrochanteric shortening osteotomy [14] was performed beneath the lesser trochanter to avoid excessive stretching of the sciatic nerve. After hip reduction with a femoral trial stem only seated in the proximal fragment, the length of bone resection was decided according to the overlapping of the femoral segments. After the shortening osteotomy, two femoral fragments were held face to face by two bone holding forceps and reamed again. For the proper restoration of femoral offset, the scheduled conical stem was implanted distally and connected to a longer femoral head if necessary. Prophylactic cable fixation was used before the insertion of the uncemented Wagner Cone Prosthesis Hip Stem (Zimmer, Warsaw, IN, USA) to prevent iatrogenic splitting of the femur. Rotation of the trial stem was initially estimated in 15°–20° of anteversion relative to the lower leg bent at a right-angle. The anteversion of implanted cone stems could be slightly increased or decreased based on the hip stability after reduction. The wear bearing materials of this cohort consisted of ceramic-on-ceramic in 19 hips and metal-on-poly in 2 hips. The osteotomy site was grafted with cancellous bone from the femoral head. Patients were hospitalized in an average of 7.7 days (range, 6–11 days). Partial weight bearing was encouraged at 3–6 weeks postoperatively. Twelve weeks later, full weight bearing was usually allowed if osseous healing was positive at the osteotomy sites.
Fig. 1. Radiographs are shown of a 59-year-old woman with Crowe type IV dysplastic right hip. (A) The preoperative femoral off-set was 2.3 cm. The preoperative leg length discrepancy (LLD) was 5.2 cm and the preoperative Harris hip score was 58. (B) At 3-month follow up, bone union was detected on the lateral half of the osteotomy site. The postoperative femoral off-set was 3.4 cm and leg lengthening was 3.7 cm. The postoperative LLD was 14 mm. (C) At 1-year follow up, the osteotomy site was completely healed. The postoperative Harris hip score was 97. (D) No subsidence or radiolucent lines around the prosthesis was found at 4-year follow up. The amount of radiographic leg lengthening was measured by subtracting the amount of intraoperative femoral resection from the distance between the top of the greater trochanter preoperatively and postoperatively on radiographs [16]. LLD indicated the length discrepancy of lower extremities which was measured with a tape by measuring the distance between the anterior superior iliac spine and the medial malleolus [15].
Clinical and Radiographic Evaluation Clinical results were evaluated with Harris Hip Score (HHS) and leg length discrepancy (LLD) preoperatively, at 6 months and 1 year postoperatively, and then yearly until the last follow-up. LLD indicated the length discrepancy of lower extremities which was measured with a tape by measuring the distance between the anterior superior iliac spine and the medial malleolus [15]. Clinical failure was defined as the need for revision surgery. Anteroposterior and false profile lateral radiographs were made at each follow-up visit. Radiographic evaluation was performed by one surgeon (J. Zhu) including femoral off-set, leg lengthening, loosening signs and bone union of femoral osteotomy. The femoral off-set was defined by measuring the distance on radiographs between the femoral axis and the femoral head center. The amount of radiographic leg lengthening was measured by subtracting the amount of intraoperative femoral resection from the distance between the top of the greater trochanter preoperatively and postoperatively on radiographs [16]. The stability of the femoral components was assessed radiographically as previously described [17]. Stable fixation by bone ingrowth was defined as no subsidence or radiolucent lines around the prosthesis. Provided consolidation presented across the osteotomy sites, osseous healing was determined.
of these patients postoperatively improved (Fig. 1 and Table 1). Femoral shortening subtrochanteric osteotomy was performed with an average femoral resection of 1.5 cm (range 1.0–2.5 cm). Limp that characterized by excessive lateral trunk movement over the affected hip, was postoperatively corrected or improved in 20 hips, based on a function of the lateral head motion [18]. Twenty hips survived at the last follow-up without observed subsidence. One hip was dislocated in a 77 years old lady and manipulated with closed reduction at first postoperative month (Fig. 2). The same hip was revised at 6 months follow-up due to early stem loosening between the stem and distal femoral fragment. No infection was found following the surgery in this cohort. Postoperative sciatic nerve palsy occurred in three hips with leg lengthening of 4.5 cm, 5.5 cm and 6.8 cm. Two cases of nerve palsy (3/5) disappeared in 3 months. The other case which had the maximal leg lengthening of 6.8 cm in this series improved from 2/5 to 4/5 after one year. All acetabular implants survived at last follow up without any complication. Nonunion of the femoral osteotomy site was recorded in the previous hip which was revised at 6 months follow up due to early stem loosening. The average time to bone union for the other 20 hips was 5 months (range 3–9 months). One case of delayed union at the femoral osteotomy site was found and healed at 9-month follow-up.
Statistical Analysis Preoperative and postoperative HHS scores, LLD and radiographic evidences were compared using t test. Significance was determined at a P value of b0.05. Results The average follow-up of total 21 hips lasted 40 months (range, 24–60 months). The average HHS score, LLD and radiographic evaluation
Table 1 Preoperative and Postoperative Radiographic and Clinical Results.
Harris hip score Leg discrepancy (cm) Femoral off-set (cm) Leg lengthening (cm)
n
Preoperative Value
Postoperative Value
P Value
21 20 21 21
52.4 ± 6.8(35–63) 4.7 ± 1.1 (2–7) 1.9 ± 0.5 (1–2.6)
90.5 1.2 3.3 3.8
b0.001 b0.001 b0.001
± ± ± ±
15.1 (26–97) 0.4 (0–2) 0.4 (2.8–4) 0.9 (3–6.8)
Values are expressed as mean ± standard deviation with range in parentheses.
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
J. Zhu et al. / The Journal of Arthroplasty xxx (2014) xxx–xxx
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Fig. 2. Radiographs are shown of a 77-year-old woman with Crowe type IV dysplastic right hip. (A) The preoperative leg length discrepancy was 6 cm and the preoperative Harris hip score was 35. (B–D) Hip stability was reconstructed by primary hip replacement with subtrochanteric shortening osteotomy. However, hip dislocation happened at first postoperative month and manipulated with close reduction. (E) At 6-month follow up, stem loosening was clearly detected, whereas osseous healing wasn't completed at the osteotomy site. (F) The hip was revised with a longer cementless stem and a locking plate. During the surgery, prosthesis loosening was identified between the stem and distal femoral fragment. However, the conical stem was still stable in the proximal femoral fragment with small amount of osteointegration.
Discussion Good clinical results and meticulous surgical technique of nonmodular cementless prostheses, such as the Wagner Cone Stem, were reported in total hip arthroplasty for Crowe type I and II dysplastic hips [6–9]. However, Crowe type IV dysplastic hips present the greatest degree of anatomical abnormality [1]. The restoration of hip rotation center with the common need for concurrent femoral osteotomies in Crowe type IV dysplastic hips can lead to technical difficulties in ensuring femoral deformity correction and stem stability. To our knowledge, our report represents that first study of hip arthroplasty with the nonmodular cementless Wagner stem for treating Crowe type IV dysplastic hips, with femoral shortening subtrochanteric osteotomy. The position of acetabular components is optimal when reconstructed in a normal anatomic position [19]. High or superolateral placement of the acetabular components is avoided by many surgeons because an unfavorable biomechanical environment could lead to greater joint contact forces, less mechanical advantage of the abductors, and higher rates of acetabular component loosening [16,20]. Slight elevation of the hip center without lateralization may be acceptable since a recent report of 30 hips treated with this technique showed no evidence of loosening at an average of 15.2 year follow-up [21]. Moderate medialization of the acetabular components could be an alternative solution in some cases due to its known biomechanical advantage and clinical durability [20,22]. However, a small cup or cotyloplasty technique was not advocated in this study. Considering the relatively young age of these patients and the desire for bone stock preservation for potential hip revision arthroplasty, ceramic bearing and structural acetabular autograft was preferred in most cases. After the anatomic placement of acetabular components, femoral shortening osteotomy was needed to overcome the excessive stretching of the sciatic nerve. Different techniques of femoral shortening including proximal, diaphyseal and distal osteotomies have been described [23–25]. These techniques were difficult to be compared because of the differences in the types of hips, ages of patients and follow-up periods under investigation [26]. Short or medium term results of Crowe IV hips treated with subtrochanteric shortening osteotomy showed excellent healing rates of the osteotomy, ranging from 93% to 100% [24,27].
Hence, transverse subtrochanteric osteotomy was suggested in this study. Only one case (4.8%) of nonunion was found at the osteotomy site following postoperative dislocation and early loosening between the stem and distal femoral fragment. An oblique, step-cut or chevron osteotomy may increase bony apposition and torsional stability [28–30]. However, these complex geometrical osteotomy techniques require detailed preoperative planning and could prevent intraoperative adjustment. On basis of the press-fit between the stem and the femoral bone cortex, the nonmodular conical stem obviated the complexities and potential risks which were indicated at the metaphyseal neck-stem interface of modular stems. The instability and early loosening of the stem were prevented in Crowe type I and II dysplastic hips [6–9] due to eight longitudinal sharp ribs of the tapered stem, which allowed adequate press-fit and good orientation of the implant in a dysplastic femur. In this study, after the transverse subtrochanteric osteotomy, the press-fit in a severely dysplastic femur was required in both proximal and distal femoral fragments. To obtain enough length of engagement between the stem and distal femoral fragment, the site of subtrochanteric osteotomy in this study was suggested at a level close to the less trochanter. Additionally, the surface area of the conical stem was greater in the proximal than the distal part. With a continuous surface press-fit, a uniform load transfer per unit of area can be assumed [8]. Therefore, the load distribution in the conical stem was greater in the proximal region which would benefit osteointegration of the stem and reduce the risk of nonunion at osteotomy site. Radiographic follow-up showed great osteointegration of the stem in the proximal region of dysplastic femurs [8]. The average time of 5 months for bone union at osteotomy site in this study was comparable to previous results [16,30]. Several factors related to bone union at the osteotomy site. Firstly, aggressive reaming in the femoral canal resulted in a release of bone marrow cells and degeneration of the endosteum, both of which had the potential to form new bone at the osteotomy site [31]. Furthermore, the preparation of osteotomy sites by removing periosteum circumferentially, as well as the prevention of perioperative femoral fracture by using cerclage wiring around the outer surface of the cortex could injury the osteoblastic activity of the periosteum. Moreover, the stability of the interface between two femoral osteotomy fragments was emphasized. After shortening osteotomy and derotation of the proximal femoral fragment,
Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
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J. Zhu et al. / The Journal of Arthroplasty xxx (2014) xxx–xxx
it was difficult to keep the congruency between proximal and distal canal diameters. To achieve such stability, osteosynthesis was suggested in this situation [32]. The only one case of nonunion in this study was revised at six-month follow-up due to stem loosening. This 77 years old lady got dislocation 1 month after surgery as she over flexed her hip. Closed reduction was manipulated under general anesthesia. Because of high dislocated hip (Fig. 2C), relatively high traction force was manipulated on her low extremity during reduction. During the revision surgery, the conical stem was still found stable in the proximal femoral fragment with small amounts of osteointegration. A previous dislocation and following closed reduction could compromise the press-fit between the stem and distal femoral fragment, because the uncemented conical stem is easy to disengage under traction. Therefore, the movement of stem in distal femoral fragment and the instability between the two femoral osteotomy fragments were introduced, which accounted for the bone nonunion and early stem loosening in this case. The short-term functional outcomes greatly improved in the 20 hips of this study. The increased HHS score and improved limp of these hips mostly resulted from an ease of preoperative hip pain, leg lengthening and the restoration of femoral offset. The average leg lengthening of 3.8 cm in this series was safe from the risk of post-operative nerve palsy [33]. The mean postoperative femoral offset of 3.3 cm in this series was comparable to 3.4 cm on normal population [34,35]. The increased postoperative femoral offset restored abductor muscles lever arm, whereas it reduced joint reaction forces which minimized the rate of bearing wear [3]. Recently, dual modular prostheses were preferred for the advantage of proper restoration of femoral offset. A nonmodular stem, however, was still effective to properly restore femoral offset in this study by distally implanting the conical stem and using a longer femoral head. This study has several limitations. Firstly, there was no broad consensus on the definition of modular and non-modular stem. In this study, the Wagner Cone prosthesis was identified as a nonmodular stem as other femoral stem which was monoblock or only had a neck-head junction [5,36]. Secondly, the duration of follow-ups in this study has been short since the new version of Wagner Cone stem was introduced to the market in 2006. Two of twenty patients didn't return to our clinic at the last follow up. We considered, however, it was reasonable to include the two patients, because they were interviewed by telephone and still satisfied with the involved hips. The third limitation is the relatively small number of patients. At the early stage of our practice, we were limited by both the learning curve and conservative patient selection. In summary, good survivorship and joint function were identified in Crowe type IV dysplastic hips treated with the uncemented conical stem. Compared with modular prostheses and custom-made prostheses, the non-modular conical stem obviated the complexities, high medical cost and potential risk at the neck-stem interface but also poses a challenging hip reconstruction. Acknowledgments The authors greatly value the writing assistance from Dr. John C. Clohisy from Washington University School of Medicine in St. Louis USA. The study was financially supported by National Natural Science Foundation of China (no. 81171705, 81101381 and 81101379), Shanghai Municipal Commission of Health and Family Planning Foundation (no. 20134002) and Research Foundation of Shanghai Jiaotong University Medical School (no. YZ1002). References 1. Noble PC, Kamaric E, Sugano N, et al. Three-dimensional shape of the dysplastic femur: implications for THR. Clin Orthop Relat Res 2003;417:27. 2. Sugano N, Noble PC, Kamaric E, et al. The morphology of the femur in developmental dysplasia of the hip. J Bone Joint Surg (Br) 1998;80:711.
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Please cite this article as: Zhu J, et al, Total Hip Arthroplasty With a Non-Modular Conical Stem and Transverse Subtrochanteric Osteotomy in Treatment of High Dislocated Hips, J Arthroplasty (2014), http://dx.doi.org/10.1016/j.arth.2014.11.002
