Orthopaedic Surgery Hip

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1 Transverse Subtrochanteric Shortening Osteotomy in Total Hip Arthroplasty for Severe Hip Developmental Dysplasia Myung-Sik Park Professor, Department of Orthopaedic Surgery, Chonbuk National University Hospital, Jeonju Abstract Thirty-five total hip arthroplasties (33 patients) were performed in cases of Crowe grade III or IV hip dysplasia using subtrochanteric shortening osteotomy with two kinds of femoral stem: monoblock and modular type. All acetabular components were used with a cementless cup. The average patient age was 47.8 years, and the average follow-up time was 5.1 years. Acetabular reconstruction was performed using autogenous femoral head in 11 hips. Radiologically, hip centres were nearly normalised with vertical heights of 10.6mm elevation and horizontal lengths of 1.7mm compared with uninvolved sites. Leg length discrepancies were improved from 4.7 to 1.5cm. Early post-operative complications included two non-unions at the osteotomy site, one dislocation after monoblock stem, one case of peroneal nerve palsy and one subsidence occurring after modular stem placement. The non-union fractures were managed with bone grafts and modular stems. The dislocation was managed with closed reduction and an abduction brace. The peroneal nerve patient was managed with an ankle stop brace. Late complications included cup loosening, but there was no loosening in the femoral stem. The average Harris Hip Score was improved from 36 to These data demonstrate that a cementless modular femoral stem is the more useful device for treating hip dysplasia patients. Keywords Total hip arthroplasty, developmental dysplasia, modular femoral stem Disclosure: This paper was supported by funding from Chonbuk National University Hospital Research Institute of Clinical Medicine and partially supported by sanofi-aventis Co. Received: 20 September 2010 Accepted: 24 January 2011 Citation: European Musculoskeletal Review, 2011;6(1):55 9 Correspondence: Myung-Sik Park, , Department of Orthopaedic Surgery, Chonbuk National University Hospital, Jeonju, Korea. E: mspark@jbnu.ac.kr The high developmentally dislocated hip involves one of the most challenging reconstructive surgical procedures in total hip arthroplasty. There are many anatomical deformities that contribute to the complexity of arthroplasty. Poor acetabular bone stock, high dislocation of the proximal femur and narrowness of the femoral canal cause technical difficulties during surgery. Soft tissues surrounding the hip joint are frequently contracted because of the chronicity of dislocation. 1 The longevity of hip arthroplasty in these patients has improved through restoration of the anatomical hip centre, which decreases the hip joint reaction force and creates an improved lever arm for the abductor musculature. 1 3 Restoration of the anatomical hip centre frequently requires limb lengthening in excess of 4cm and increases the risk of neurological traction injury. 1,4,5 Surgical techniques used for high-riding dislocations of the hip are different from those used to correct simple acetabular dysplasia. If shortening of the femur is not performed, reduction of the femoral head into the true acetabulum is impossible, and there is the risk of excessive lengthening of the neurovascular structures. One option for restoring the anatomical hip centre is subtrochanteric femoral shortening osteotomy. Various techniques for shortening osteotomies have been described. 6 9 Bruce et al. recently reported on five cases using a modular cementless femoral system combined with a transverse osteotomy for femoral shortening. 7 The risk of surgical complications associated with total hip arthroplasty increases as the extent of dislocation according to the Crowe classification 1 becomes more severe, depending on the degree of developmental dysplasia of the hip joint. Major complication rates reported in the literature for total hip arthroplasty treatment of severe acetabular dysplasia using shortening femoral osteotomy range from 12 to 41%. 1,7 12 Patients with untreated high developmental hip dislocations frequently develop symptoms of secondary arthritis during the fourth and fifth decades of life. 1,10,13 These patients presented myriad challenges for total hip arthroplasties. The dysplastic acetabulum is hypoplastic and its bone density is often low because of lack of stress remodelling. The femur is small and often exhibits an excessive neck shaft angle and increased anteversion, which shifts the greater trochanter to a more posterior position. Femoral shortening osteotomy was described by Klisic and Jankovic 6 for high dislocations and was adapted by Crowe et al. 1 to include simultaneous hip arthroplasty. The two largest series reported in the literature include a study of 28 hips treated with a step-cut shortening osteotomy based on pre-operative radiographic templating, 8 and a report on 25 hips treated with a transverse shortening osteotomy based on intra-operative femoral length. 11 The purpose of our study is to present a transverse osteotomy technique and complications related to the femoral stem. Materials and Methods From November 1998 to February 2003, we performed 76 total hip arthroplasties for cases of arthritis secondary to hip dysplasia. Of these, 35 hips (in 33 patients) were managed with transverse femoral TOUCH BRIEFINGS

2 Table 1: Patient and Demographics Data Mean age 47.8 years (22 69 years of age) Gender (Male/female) 11/22 patients Crowe grade Crowe III (13 hips)/crowe IV (22 hips) Operation time 2.9 hours Mean blood loss ml Harris Hip Score Pre-operation (36)/post-operation (82.4) Leg length discrepancy Pre-operation (4.7cm)/post-operation (1.5cm) Table 2: Complications Early Post-operative Non-union 2 Femoral stem subsidence 1 Dislocation 1 Peroneal nerve palsy 1 Late Post-operative Cup loosening 2 shortening osteotomy reviewed for final evaluation. Two cases had a history of previous pelvic osteotomy, and one had a dislocation due to failure of a previous total hip arthroplasty performed in another hospital. There were 22 women and 11 men with a mean age of 47.8 years (range years) at the time of index surgery and the mean follow-up after surgery was 5.1 years (range years) (see Table 1). No patients were lost in the last follow-up. All operations were performed by the author and attempted to restore the anatomical hip centre. The surgical approaches were anterolateral in 27 hips and posterior in eight hips. All the acetabular and femoral components were cementless. Standard monoblock femoral stems BiContact (Aesculap), Duofit (SAMO) and C2 (Lima) were used in 16 hips, and modular femoral stems S-ROM (DePuy), MP (Waldemar Link) and Revision modular (Lima) were used in 19 hips. Porous-coated acetabular components with dome screws were used in all hips (with an average of two screws per hip). A structural femoral head autograft was used in 11 hips for acetabular shelf reconstruction. The other cup was contoured by flying buttress autogenous grafts from acetabular reaming. Clinical and radiographic post-operative evaluations were performed after six weeks; three, six and 12 months; then yearly. The clinical evaluation was carried out based on Harris Hip Scores 14 and, subjectively, the surgical outcomes were described on a four-point scale as excellent, good, moderate or not improved, or unsatisfactory. Gait was rated in a manner previously described: 15 none, slight limp (detected by trained observer), moderate limp (detected by patient or family) or severe limp (gait markedly altered). The stability of the femoral component was assessed as bone-ingrown fixation, stable fibrous fixation or unstable fixation according to the fixation/stability score described by Engh et al. 16 Surgical Techniques All patients were placed in the lateral decubitus position, and a transverse subtrochanteric shortening osteotomy was performed as previously described. 8,17 Initially, reaming of the femoral canal was performed before acetabular preparation and femoral osteotomy. The osteotomy was usually performed at a level >4cm distal from the level of the medial femoral neck. The other surgical technique used in our study involved preserving the proximal portion at the level of the proximal component of the modular stem. After subtrochanteric transverse osteotomy was performed, a proximal fragment of the femur was retracted cephalad and maintained with two Steinmann pins. The true acetabular site was checked using a guided K-wire under C-arm fluoroscopy. All the acetabular cups were fixed with two or three dome screws, and uncovered portions of the metal shell were covered with an autogenous graft from the acetabular reaming. If the proximal part was insufficient to cover the acetabular cup trials, we used an autogenous femoral head and fixed it with two screws. We then inserted a femoral stem trial into the proximal fragment of the femur, reduced it with a femoral component to the acetabular cup and checked its stability. In a hip reduction, a distal part of the femur was reduced to the proximal segment. The amount of overlapping femoral shaft was resected gradually for shortening, and the amount of resection was minimised as much as possible. If the shaft is excessively resected, there will be no means of restoring its length. This technique allows an accurate intra-operative measurement for femoral resection. The osteotomy was then reduced with the trial stem and rotational alignment was checked. The osteotomy site was augmented with a morselised autogenous graft from the acetabular reaming or a resected femoral fragment with a cerclage. If the osteotomy site was rotationally unstable, additional plate and screw fixation was performed. During the operation, we did not perform continuous intra-operative neurological monitoring. Post-operatively, patients were kept at partial weight-bearing for six weeks and progressed to full weight-bearing thereafter. Osteotomy healing was assessed using post-operative radiographs at six weeks and three, six and 12 months. The criteria for union of the osteotomy included callus formation at the osteotomy site and restoration of cortical continuity between the proximal and distal fragments according to anteroposterior or lateral radiographs. Changes in hip centre were measured according to Russotti and Harris using pelvic radiographs. 18 These were determined by measuring the horizontal location (the horizontal distance from the inferior point of the teardrop) and the height (the vertical distance from the inter-teardrop line). The post-operative hip centre was also measured with the pelvis lying flat. Russotti and Harris defined proximal placement of the socket as 35mm vertical displacement from the inter-teardrop line. The leg length discrepancy was pre-operatively and post-operatively measured in all patients. One patient had undergone arthroplasty in both hips, so the hip centre of this patient was determined post-operatively by radiography on a plain anteroposterior view. A component loosening was defined as either progressive symptomatic radiolucency >2mm surrounding the femoral or acetabular implant, or a progressive component with a migration on serial radiographs. Patients were examined at six weeks, three months, six months and yearly after hip arthroplasty. Presence of a limp, use of an assistive walking device and Harris Hip Scores 14 were documented during each post-operative examination. Results Complications Intra-operative cracks or fractures of the proximal segment occurred soon after surgery in three hips. All of these fractures were managed with cerclage wires. Early complications during one year postoperatively. In patients with monoblock stems, there were two nonunions and one dislocation in the osteotomy sites. The dislocation was managed with closed reduction under anaesthesia and an 56 EUROPEAN MUSCULOSKELETAL REVIEW

3 Transverse Subtrochanteric Shortening Osteotomy in Total Hip Arthroplasty applied abduction brace, and did not develop further problems. The two non-union cases were managed with a bone graft and the monoblock stem replaced with a modular stem. Among patients with modular stems, one patient developed femoral stem subsidence two months after the operation; the stem was replaced with a larger diameter modular stem. One case of peroneal nerve palsy was revealed after operation, but this patient improved during the followup period. Late complications during follow-up period over one year, two cup loosening noted around five years; one was associated with the patient falling down and the other was due to cup migration. These were managed with a hook-plate cup cage, but there was no loosening in the femoral stem at last follow-up (see Table 2). Figure 1: Pre-operative Radiograph of a Left High Dislocation (Crowe IV) of the Hip of a 58-year-old Woman Clinical Results The average Harris Hip Score for the patients showed an improvement from 36 points pre-operatively to 82.4 points post-operatively. The post-operative average leg length discrepancy in patients with unilateral dysplasia was 42mm (range 35 60mm). The difference between leg lengths was decreased from an average 4.7cm (range cm) to 1.5cm (range cm). We also evaluated the complaints of the patients about the surgical outcomes through the administration of a questionnaire that included items in terms of pain (including thigh pain) and functional capabilities. The surgical outcomes were graded as excellent for 11 patients, good for 18 patients, moderate for three patients and unsatisfactory for one patient. The presence and degree of a pre-operative limp among the patients was graded as none (0%), mild (17%), moderate (57%) or severe (26%), 16 and the post-operative limp was graded as none (30%), mild (49%), moderate (15%) or severe (6%). Figure 2: Post-operative Radiograph at Five-year Follow-up Showing Uncemented Acetabular and Modular Femoral Stems (Link MP Stem) After Subtrochanteric Shortening Osteotomy Radiographic Evaluation The mean acetabular component size was 48.46mm (range mm). Radiologically, the average horizontal distance of a normal hip centre is 32.5mm (range mm) and the vertical distance is 18.3mm (range mm) after magnification correction. The average horizontal length of the total hip was 30.8mm (range mm) and the average vertical height of the total hip arthroplasty was 28.9mm (range mm). The hip centre was nearly normalised, with 10.6mm elevations in vertical height and a horizontal length of 1.7mm compared with uninvolved sites. The mean osteotomy resection was 34mm in length (range 20 42mm). Thirty-three of the 35 osteotomies healed without any complication. The average time for radiographic union was 3.2 months (range months). Use of Assistive Walking Devices Assistive devices were not required pre-operatively in 52% of the patients. A cane or crutches were needed by 44% of the patients prior to surgery, and 4% required a wheelchair or were unable to walk. Post-operative use of assistive devices was not required by 85% patients, while 9% needed a cane or crutches and 6% required a wheelchair or were unable to walk. Revision Surgery Revision surgery was performed in three patients within one year after the initial operation. The reasons for two revisions were nonunions in the osteotomy site after monoblock stem placement; these were managed by additional bone grafts and distally fixing modular stems. With one modular femoral stem, femoral stem subsidence occurred two months after operation. This was managed with a larger diameter modular femoral stem. During follow-up, cup loosening was observed in two hips. Both were classified as Crowe type IV, and were managed with hook-plate cup cages. During the follow-up period, there was no loosening noted in the femoral stem. Discussion Total hip arthroplasty in patients with developmental dysplasia of the hip has been associated with many complications and unfavourable outcomes compared with total hip arthroplasty carried out in patients with degenerative disease. The most common problem associated with dysplasia is insufficient acetabular bone coverage, which can compromise the durability of component fixation. One option for restoring the anatomical hip centre is subtrochanteric femoral shortening osteotomy described by Klisic and Jankovic. 6 Other shortening osteotomy techniques have been described, such as stepcut, double-chevron, oblique and transverse shortening osteotomy. Among these procedures, we chose a transverse osteotomy since it is easy to perform intra-operatively. EUROPEAN MUSCULOSKELETAL REVIEW 57

4 Figure 3: Pre-operative Radiograph Showing a Right High Hip Dislocation (Crowe IV) in a 46-year-old Woman femoral head and medialisation of the acetabular cup that was commonly employed. In this investigation, bulk structural autogenous bone grafting was used in 11 hips, and flying buttress grafting was used in others. The location of the true acetabulum was difficult to determine in most cases, but following the elongated and attenuated capsule down to the true acetabulum was often helpful. During the operations, we frequently used intra-operative C-arm fluoroscopy to find the location of the true acetabulum. Using this method, we successfully placed all acetabular components into the true acetabulum. The average size of femoral and acetabular components was significantly smaller than standard implants. Therefore, detailed pre-operative templating and planning were essential. Figure 4: Post-operative Radiograph at 4.2-year Followup Demonstrating Bone Ingrowth at the Osteotomy Site with a Modular Femoral Stem (Lima Modular Revision Stem) Recently, Bruce et al. 7 and Masonis et al. 20 reported on usage of a modular cementless femoral system combined with transverse osteotomy for femoral shortening osteotomy. Major complication rates reported in the literature ranged from 12 to 41%. 7,20 We tried this technique using two femoral stems, one a primary monoblock femoral stem and the other a distally fluted femoral stem. We observed two non-unions related to osteotomy and one stem subsidence in the early post-operative period with a transverse subtrochanteric shortening osteotomy. Both non-unions were associated with a monoblock femoral stem. Subsidence of a modular femoral stem was caused by a smaller stem rather than a medullary canal. Onodera et al. 21 reported that the S-ROM modular femoral stem provides sufficient rotational stability in both proximal and distal parts of the osteotomy in 14 hips except one at six months follow-up. Onodera et al. 21 also concluded that another benefit of the S-ROM design is easy control of anteversion of the stem that should theoretically decrease the rate of dislocation by allowing the surgeon to adjust the version to give a more stable arc of motion. Although with some monoblock stems non-union was revealed at the osteotomy site, we preferred to use a distally fixed fluted stem recently because control of anteversion of the S-ROM was not easily compared with other distally fixed modular stems (such as the Link [see Figures 1 and 2] or Lima [see Figure 3 and 4] modular stems), and there were also difficulties in leg length correction. We observed a distally divergent halo sign around the distal cloth pin of an S-ROM design after three years in one hip. However, the recent development of a short distally fixed modular femoral stem allows initial stabilisation and correction of leg length discrepancy, and does not require additional fixation to the osteotomy site. Other modular distally tapered stems (Lima or Link modular stems) also have the drawback of subsidence compared with the S-ROM modular stem. Dysplasia of the acetabulum leaves deficiency, particularly in the superior acetabulum, in high developmental dislocations as a challenging reconstructive procedure. The location of the acetabular cup in developmental dysplasia of the hip joint has been a controversial matter. According to Linde and Jensen, 19 the severity of femoral head dislocation before surgery is associated with a higher frequency of dissociation of the acetabular cup. Linde and Jensen tried to position the acetabular cup exactly within the true acetabulum in all cases. We predicted that the frequency of dissociation of the acetabular cup would be higher in cases where the acetabular cup is not positioned within the true acetabulum. If there were inadequacies in the acetabular cup, we tried autogenous bone grafting using a In our study, three out of 35 hips required revision surgery one year after the initial operation. This is consistent with the limited number of published reports on this topic. 1,8 12 Repeat surgery was directly related to the use of a standard monoblock femoral stem; this stem usually requires metaphyseal fitting, so distal fragments are not tightly fixed. One drawback of the modular stem is mismatching of the medullary canal. We found that transverse osteotomy resulted in a union rate identical to a recent published report using a step-cut method, 8 and was technically easier to adjust intra-operatively to correct rotational abnormalities. Our data support the use of transverse subtrochanteric femoral osteotomy and cementless acetabular fixation at the anatomical hip centre for correcting high developmental hip dysplasia with secondary arthritis. Subtrochanteric shortening osteotomy appears 58 EUROPEAN MUSCULOSKELETAL REVIEW

5 Transverse Subtrochanteric Shortening Osteotomy in Total Hip Arthroplasty to be a safe and reliable procedure for restoring the anatomical hip centre and trochanteric rotation without neurological injury. Although the patients in our series experienced substantial improvements in pain reduction and hip function after total hip arthroplasty, their final hip scores were lower than those for patients undergoing hip arthroplasty for degenerative osteoarthritis. Continuous follow-up is required to establish the long-term results of this procedure. n 1. Crowe JF, Mani VJ, Ranawat CS, Total hip replacement in congenital dislocation and dysplasia of the hip, J Bone Joint Surg Am, 1979;61(1): Kelley SS, High hip center in revision arthroplasty, J Arthroplasty, 1994;9(5): Pagnano MW, Hanssen AD, Lewallen DG, Shaughnessy WJ, The effect of superior placement of the acetabular component on the rate of loosening after total hip arthroplasty: long term results of patients who have Crowe type II congenital dysplasia of the hip, J Bone Joint Surg Am, 1996;78(7): Yoder SA, Brand RA, Pederson DR, O Gorman TW, Total hip acetabular component position affects acetabular loosening rates, Clin Orthop, 1988;228: Cameron HU, Eren OT, Solomon M, Nerve injury in the prosthetic management of the dysplastic hip, Orthopedics, 1998;21(9): Klisic P, Jankovic L, Combined procedure of open reduction and shortening of the femur in treatment of congenital dislocation of the hips in older children, Clin Orthop, 1976;119: Bruce WJ, Rizkallah SM, Kwon YM, et al., A new technique of subtrochanteric shortening in total hip arthroplasty, J Arthroplasty, 2000;15(5): Sener N, Tozun I, Asik M, Femoral shortening and cementless arthroplasty in high congenital dislocation of the hip, J Arthroplasty, 2002;17(1): Yasgur DJ, Stuchin SA, Adler EM, DiCesare PE, Subtrochanteric shortening femoral osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip, J Arthroplasty, 1997;12(8): Symeonides PP, Pournaras J, Petsatodes G, et al., Total hip arthroplasty in neglected congenital dislocation of the hip, Clin Orthop, 1997;341: Reikeraas O, Lereim P, Gabor I, et al., Femoral shortening in total hip arthroplasty for completely dislocated hips, 3 7 year results in 25 cases, Acta Orthop Scand, 1996;67(1): Chareancholvanich K, Becker DA, Gustilo RB, Treatment of congenital dislocated hip by arthroplasty with femoral shortening, Clin Orthop, 1999;360: Harris WH, Etiology of arthritis of the hip, Clin Orthop, 1986;213: Harris WH, Traumatic arthritis of the hip after dislocation and acetabular fractures, treatment by mold arthroplasty, J Bone Joint Surg Am, 1969;51(4): Johnston RC, Fitzgerald RH, Harris WH, et al., Clinical and radiographic evaluation of total hip replacement, J Bone Joint Surg Am, 1990;72(2): Erratum in: J Bone Joint Surg Am, 1991;73(6): Engh CA, Glassman AH, Suthers KE, The case for porouscoated hip implants. The Femoral side, Clin Orthop, 1990;261: Nagoya S, Kaya M, Sasaki M, et al., Cementless total hip replacement with subtrochanteric femoral shortening for severe developmental dysplasia of the hip, J Bone Joint Surg Br, 2009;91(9): Russotti GM, Harris WH, Proximal placement of acetabular component in total hip arthroplasty, J Bone Joint Surg Am, 1991;73(4): Linde F, Jensen JS, Socket loosening in arthroplasty for congenital dislocation of the hip, Acta Orthop Scand, 1988;59(3): Masonis JL, Patel JV, Miu A, et al., Subtrochanteric shortening and derotational osteotomy in primary total hip arthroplasty for patients with severe hip dysplasia. 5 year follow-up, J Arthroplasty, 2003;18(3 Suppl 1): Onodera S, Majima T, Ito H, et al., Cementless total hip arthroplasty using the modular S-ROM prosthesis combined with corrective proximal femoral osteotomy, J Arthroplasty, 2006;21(5): EUROPEAN MUSCULOSKELETAL REVIEW 59