| | Results on Total Hip Arthroplasties With Femoral Shortening for Crowe's Group IV Dislocated HipsReceived 6 April 2005; accepted 20 February 2006. Abstract We performed total hip arthroplasties in 11 women with Crowe's group IV completely dislocated hips, with a mean age at surgery of 59.6 years and a mean follow-up of 65 months. In all cases, femoral shortening was achieved using step-cut osteotomy. All acetabular cups were placed in their anatomical locations. The mean Merle d'Aubigne hip score improved from 10.9 points to 16.9. There was no case of nonunion or malunion in the osteotomized site. Temporary numbness was observed in 2 hips, which subsided within 3 weeks without any treatment. One hip had to be revised 8 years after surgery because of aseptic loosening of the stem. Our study shows that total hip arthroplasty, incorporating step-cut femoral shortening, provides acceptable results for completely dislocated hip. Total hip arthroplasty for Crowe's group [1] IV complete dislocation of the hip is problematic. Complications and failures are more common compared with total hip arthroplasty for a nondislocated hip. In a completely dislocated hip, the distorted anatomy may bring about abnormal neurovascular structures, leg length discrepancy, soft-tissue contractures, excessive anteversion of the femoral neck-shaft angle, and transverse disorientation of the abductor muscles, possibly making their function less efficient. Such abnormalities can be problematic before and during arthroplasty and make it difficult to fully assess the amount of limb lengthening required, or the extent of soft-tissue release, to achieve good patient outcomes. In most previous reports regarding total hip arthroplasty for high-riding dislocated hips, the patients reviewed were those suffering Crowe's group III and IV dislocation 2, 3, 4; however, there are limited studies of patient groups solely in Crowe's group IV where complete dislocation of the hip occurs. To address this limitation, we have set out our procedural experience using step-cut osteotomy and have retrospectively evaluated the postoperative results of total hip arthroplasty for patients presenting only with Crowe's group IV completely dislocated hips. Patients and Methods  Between 1990 and 2002, total hip arthroplasties were performed on 12 adult female patients with Crowe's group IV completely dislocated hips. One patient was lost to follow-up study. The remaining 11 hips of 11 patients were analyzed in this series. The mean age of the patients at surgery was 59.6 years (range, 42-76 years), and the mean follow-up period was 65 months (range, 30-169 months). The main indication for surgery was pain around the hips. Three of the 11 patients had been treated in their childhood with Schanz's osteotomy. Surgical Procedure In preoperative planning for all 11 cases, templating was performed to determine the amount of femoral shortening necessary to prevent any neurovascular structure damage and to ensure cup placement in the original position of the acetabulum. In preoperative preparation, a figure was drawn, imaging the anticipated femoral shape after completion of the step-cut osteotomy, and accurately sized stems were selected, which would fill both proximal and distal femoral lumen to ensure that the stem shaft through the osteotomy site would have the role of an intramedullary nail. In all cases, the operations were done in the lateral decubitus position using a modified Hardinge approach [5]. All acetabular components were placed medial to the wall in the original acetabulum position, with protrusion of the medial aspect of the acetabular component into, or beyond, the medial wall, using the medial protrusion technique of Dorr et al [6], so as to obtain osseous coverage. Six cases had severe hypoplasty of the ilium, where more than 30% of the cup was uncovered by the original iliac bone. An autogenous bone graft, sculpted from the femoral head, was used to cover the superolateral portion of the cups for these 6 cases. Each acetabular component was secured with 3 or 4 screws. The femur was reamed, and then carefully using a small oscillating saw, to avoid any fracture at the site, a step-cut osteotomy was performed with the proximal cut on the lateral side and the distal cut on the medial side of the femur (Fig. 1). To correct the leg alignment, we determined the osteotomy level and calculated the proper amount of shortening to avoid the limb's being brought down more than 5 cm. The amount of preoperatively planned shortening was established by subtracting 5 cm from the distance between the preoperative highest point of the greater trochanter and the expected postoperative point of it. In the event that the limb was not able to be brought down to the preoperatively planned position, further shortening would be done during surgery. The osteotomy site is gently secured by wires or cables (Dall-Miles Cables System; Stryker, Rutherford, NJ), avoiding overtensioning, which may give rise to fracture at osteotomy site, before the stems are inserted. After insertion of the stems in the reamed femurs, these cables were fastened again tightly to achieve strong stabilization of the osteotomy site (Fig. 2). In the 3 cases where the Schanz's osteotomy had been performed previously, the shortening osteotomy was combined with a wedge correction of the angulation. Any gaps at the osteotomy site were filled with an autogenous morsellized bone sculpted from the osteotomized femoral heads. Implants Cementless acetabular components were implanted in all 11 hips: 5 S-ROM cups (Depuy, Warsaw, Ind), 3 Omnifit cups (Stryker), 2 Dura-lock cups (Depuy), and 1 Harris-Galante II cup (Zimmer, Warsaw, Ind). The outer diameter of these acetabular components was 42 mm in 2 hips, 43 mm in 1 hip, 44 mm in 2 hips, 46 mm in 3 hips, 48 mm in 2 hips, and 52 mm in 1 hip. Cementless stems were implanted in all 11 hips: 8 S-ROM stems (Depuy,) and 3 Omnifit stems (Stryker). All femoral head diameters were 22 mm. Postoperative Management Partial weight bearing was allowed after 4 weeks and progressively increased according to radiographic findings. Eight to 10 weeks after surgery, full weight bearing was permitted. Clinical and Radiographic Evaluation Clinical evaluations were made using the Merle d'Aubigne and Postel hip score [7]. Radiographic evaluation was performed with respect to the location of the hip center, the height of the greater trochanter, the component position, the osteotomized bone healing, and the presence or absence of radiolucent lines. We referenced the location of the hip center or height of the greater trochanter to a line drawn through the teardrops. The vertical height of the hip center was measured perpendicular to this reference line. The horizontal distance of the hip center was measured along this line as the distance from the lowest point of teardrop. The vertical distance of the top of the greater trochanter was measured from this reference line. Position of the acetabular component was classified according to the system of Linde and Jensen [8]. Loosening of the acetabular component was defined as according to the criteria of Hartley et al [9] and that of the femoral component, by the criteria of Martell et al [10]. Bone union at the graft, or osteotomy site, was defined as the image of cross-linking trabeculae throughout the entire gap. Clinically, the leg length discrepancy was calculated by subtracting the spina-malleolar distance (SMD) of both legs, one from the other. The amount of radiographic leg lengthening was defined as the length obtained by subtracting the amount of intraoperative femoral resection from the distance between the top of the greater trochanter preoperatively and postoperatively on radiographs (Fig. 1). Statistical Analysis To compare the difference in the mean hip score established before primary arthroplasty and that obtained at the latest follow-up, we used the Wilcoxon signed rank test. The P value generated was considered significant if it was less than .05. Results Clinical Results Using the Merle d'Aubigne and Postel system, the unrevised hip was advanced from a mean of 10.9 (range, 7-12) points to 16.9 (range, 15-18) points at the latest follow-up (P < .05). The mean pain score had confirmed recuperation from 2.8 (range, 1-4) points preoperatively to 6 (all 6), the mean mobility score progressed from 5.2 (range, 3-6) points to 5.9 (range, 5-6), and the mean walking score improved from 2.9 (range, 2-4) to 5.0 (range, 3-6) points (Fig. 3). The Amount of Femoral Resection and Leg Lengthening The mean amount of intraoperative femoral resection was 31.1 mm (range, 15-57 mm). The postoperative highest point of the greater trochanter was lowered by a mean of 70.3 mm (range, 55-97 mm) compared with its preoperative point on the radiograph. The calculated measurement (lowered greater trochanter minus intraoperative femoral resection) of radiographic leg lengthening was a mean 39.2 mm (range, 20-50 mm) (Table 1, Fig. 1). The mean percentage of radiographic leg lengthening to preoperative SMD was 5.7% (range, 2.9%-7.6%). | | |  | | Height of GT on preoperative x-ray (mm) | Height of GT on postoperative x-ray (mm) | Difference between height of GT on preoperative x-ray and postoperative x-ray (mm) | Amount of intraoperative femoral resection (mm) | Radiographic leg lengthening (mm) | |
|---|
| Case 1 | 95 | 20 | 75 | 25 | 50 | | | Case 2 | 98 | 23 | 75 | 40 | 35 | | | Case 3 | 83 | 23 | 60 | 15 | 45 | | | Case 4 | 90 | 14 | 76 | 30 | 46 | | | Case 5 | 83 | 8 | 75 | 30 | 45 | | | Case 6 | 70 | 15 | 55 | 15 | 40 | | | Case 7 | 70 | 15 | 55 | 20 | 35 | | | Case 8 | 104 | 7 | 97 | 57 | 40 | | | Case 9 | 88 | 13 | 75 | 35 | 40 | | | Case 10 | 93 | 11 | 70 | 50 | 20 | | | Case 11 | 83 | 23 | 60 | 25 | 35 | | | | |
Measured by SMD, the clinical leg length discrepancy in all patients after surgery was decreased from a presurgery mean of 47 mm (range, 40-55 mm) to 12 mm (range, 0-30 mm) at the latest follow-up. Three patients had no residual discrepancy after arthroplasty, 1 had 5 mm, 2 had 10 mm, and 1 had 15 mm. However, 20-mm clinical leg length discrepancy remained in 3 patients, and 30 mm remained in 1 patient after surgery. Radiographic Results The center of the femoral head was moved inferiorly and medially after total hip arthroplasty. The average horizontal distance of the center of the femoral head decreased from 46.0 mm (range, 28-60 mm) preoperatively to 21.6 mm (range, 13-34 mm) postoperatively. The average height of the hip center decreased from 75.0 mm (range, 55-94 mm) preoperatively to 13.9 mm (range, 10-18 mm) postoperatively. These results, using the Linde and Jensen classification system [8], showed all acetabular components to be within the true acetabulum (position 1). From radiographic inspection 6 months after total hip arthroplasty, it appeared that all osteotomy sites were fully united; the 6 superolateral bone grafts in the acetabulum were eventually united without collapse or absorption, and all prosthetic components showed no evidence of migration or loosening. The femoral components inserted into the neutral position had achieved good cortical contact in all cases, and there was no evidence of radiolucent lines around the stems, or subsidence, except in one hip, which, after 8 years, required revision surgery because of aseptic loosening of the femoral stem. Complications There were no cases of infection, but temporary femoral numbness in the distribution of the femoral nerve occurred in 2 cases; however, these symptoms disappeared within 3 weeks, without any treatment. Another patient experienced a dislocation 3 weeks after arthroplasty, necessitating a closed reduction—no further dislocation occurred. Discussion Russotti and Harris [11] reported that the average horizontal distance of an anatomic hip center in normal hips was 37 mm and the vertical height, 14 mm, whereas Yoder et al [12] reported that they are 42 and 14 mm, respectively. Using 57 female pelvic cadaver specimens with normal hips, John and Fisher [13] found the mean measurements to be 25 and 14 mm. From these data, we can see that in our series, the average location of the postoperative hip center was of normal height and a somewhat medial position. In our current series, the acetabular component could be placed near the original position of the acetabulum by using the medial protrusion technique [6] and a relatively small acetabular cup. Low revision rates have been reported when the medial protrusion technique was used for placing the acetabular cup in patients with dysplastic hips 6, 14, and Dorr et al [6] described that the use of this technique would improve the performance of the acetabular reconstruction by eliminating the need for a bone graft. As there was no failure of the acetabular components over the average 65 months of follow-up period, our results suggest that Dorr's technique gives promising short-term to mid-term results for severe hypoplasty of the ilium, as exists in Crowe's group IV completely dislocated hip. Femoral shortening is necessary to achieve a reduction of the femoral head into the cup and to prevent damage to the neurovascular structure. The exact amount of leg lengthening that may result in the occurrence of sciatic nerve dysfunction is unknown. Lewallen [15] reported acute limb lengthening of more than 2 to 4 cm to be associated with an increased risk of sciatic nerve injury, and Tanoue et al [16] noted it should be within 10% of the femoral length. In our current series, maximum radiographic leg lengthening was 50 mm, and there was no evidence of severe sciatic nerve palsy. Our experience thus suggests that leg lengthening might be safe, that is, does not impact the neurovascular structure, if it is less than 50 mm or 7.6% of the preoperative SMD. Although the clinical leg length discrepancy decreased in all cases, 4 patients, whose hip reductions were difficult, required additional intraoperative femoral resection to prevent sciatic nerve damage. They were ultimately left with more than 20 mm of clinical leg length discrepancy, possibly because of the additional resection. There are many reports about surgical procedures for femoral shortening. Reikeraas et al [3] demonstrated good results in the treatment of completely dislocated hips with transverse osteotomy. Transverse-cut or oblique-cut osteotomy is easier to perform; however, these osteotomies may result in a poor torsional stability because it is generally thought that there is a possibility of nonunion or delayed union at the osteotomy site. Reikeraas et al [3] analyzed 25 dislocated hips treated with subtrochanteric transverse osteotomy. In those series, delayed union occurred in 4%, and malunion in 4% [3]. Yasgur et al [17] reported 1 case of nonunion from a series of 8, and Masonis et al [2] reported 2 of the 21 hips that required revision surgery because of nonunion in subtrochanteric transverse osteotomy site. Step-cut osteotomy is more difficult to perform than a transverse osteotomy. However, step-cut osteotomy may be preferable in some cases to increase the overall contact area between the 2 fragments and enhance rotational stability. There were no cases of nonunion or malunion in our small series of 11 patients. Reikeraas et al [3] thought that step-cut osteotomy might reduce the circumferential contact between the endosteal cortex and femoral stem, thus, providing a less secure press fit of the stem, and tend to bring the stem into varus alignment. However, in this series, all stems were inserted into the neutral position, that is, not in varus alignment, and achieved good press fit because of preoperatively choosing a suitable stem. A stem shaft through the osteotomy site must act as an intramedullary nail. A tight fit of the femoral component both proximal and distal to the osteotomy leads to excellent stability at the osteotomy site. A modular stem allows for selection of the appropriate-sized component both proximal and distal to the osteotomy. Furthermore, greater difficulties have been encountered when performing total hip arthroplasty in cases with a previous femoral osteotomy such as the Schanz's operation (Fig. 4). Della Valle et al [18] reported that an extended trochanteric osteotomy was useful for correction of severe femoral deformity in complex total hip arthroplasties. We had 3 cases of previous Schanz's surgery, requiring wedge correction of the angulation at the step-cut site, and in all cases, accurate shortening with excellent stability was achieved. Anteversion of the femoral neck-shaft angle is larger in highly dislocated hips than in normal hips, and it is hard to insert the stem into the femur in a precise position. Excessive anteversion can be corrected by derotation with a step-cut osteotomy. However, osteotomy with derotation increases the technical complexity of the procedure. The use of the S-ROM modular stem (8 cases) allowed us to obtain the appropriate version without derotation of the femur. In conclusion, the present study showed that total hip arthroplasty, in combination with step-cut femoral shortening osteotomy, gave promising short-term to mid-term results for a Crowe's group IV dislocation of the hip in adult patients. However, a larger series of patients with a longer follow-up is required to confirm the safety and efficacy of this technique. References 1. 1Crowe JF, Mani VJ, Ranawat CS. Total hip replacement in congenital dislocation and dysplasia of the hip. J Bone Joint Surg Am. 1979;61:15. MEDLINE 2. 2Masonis 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;18:68. Abstract |
Full-Text PDF (137 KB)
|
CrossRef
3. 3Reikeraas O, Lereim P, Gobor I, et al. Femoral shortening in total arthroplasty for completely dislocated hips: 3-7 years results in 25 cases. Acta Orthop Scand. 1996;67:33. MEDLINE 4. 4Şener N, Tözün R, Aşik M. Femoral shortening and cementless arthroplasty in high congenital dislocation of the hip. J Arthroplasty. 2002;17:41. Abstract |
Full-Text PDF (200 KB)
|
CrossRef
5. 5Hardinge K. The direct lateral approach to the hip. J Bone Joint Surg Br. 1982;64:17. 6. 6Dorr LD, Tawakkol S, Moorthy M, et al. Medial protrusion technique for placement of a porous-coated, hemispherical acetabular component without cement in a total hip arthroplasty in patients who have a acetabular dysplasia. J Bone Joint Surg Am. 1999;81:83. MEDLINE 7. 7Merle d'Aubigne R, Postel M. Functional results of hip arthroplasty with acrylic prosthesis. J Bone Joint Surg Am. 1954;36:451. 8. 8Linde F, Jensen J. Socket loosening in arthroplasty for congenital dislocation of the hip. Acta Orthop Scand. 1988;59:254. MEDLINE 9. 9Hartley WT, McAuley JP, Culpepper WJ, et al. Osteonecrosis of the femoral head treated with cementless total hip arthroplasty. J Bone Joint Surg Am. 2000;82:1408. 10. 10Martell JM, Pierson RH, Jacobs JJ, et al. Primary total hip reconstruction with a titanium fiber–coated prosthesis inserted without cement. J Bone Joint Surg Am. 1993;75:554. MEDLINE 11. 11Russotti GM, Harris WH. Proximal placement of the acetabular component in total hip arthroplasty: a long-term follow-up study. J Bone Joint Surg Am. 1991;73:587. MEDLINE 12. 12Yoder SA, Brand RA, Pedersen DR, et al. Total hip acetabular component position affects component loosening rates. Clin Orthop Relat Res. 1988;228:79. 13. 13John JF, Fisher PE. Radiographic determination of the anatomic hip joint center. Acta Orthop Scand. 1994;65:509. MEDLINE 14. 14Hartofilakidis G, Stamos K, Karachalios T, et al. Congenital hip disease in adults: classification of acetabular deficiencies and operative treatment with acetabuloplasty combined with total hip arthroplasty. J Bone Joint Surg Am. 1996;78:683. MEDLINE 15. 15Lewallen DG. Neurovascular injury associated with hip arthroplasty. Instr Course Lect. 1998;47:275. MEDLINE 16. 16Tanoue M, Yamaga M, Ide J, et al. Acute stretching of peripheral nerves inhibits retrograde axonal transport. J Hand Surg Br. 1996;21-B:358. 17. 17Yasgur DJ, Stuchin SA, Adler EM, et al. Subtrochanteric femoral shortening osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip. J Arthroplasty. 1997;12:880. Abstract |
Full-Text PDF (2849 KB)
|
CrossRef
18. 18Della Valle CJ, Berger RA, Rosenberg AG, et al. Extended trochanteric osteotomy in complex primary total hip arthroplasty: a brief note. J. Bone Joint Surg Am. 2003;85:2385. Department of Orthpaedic Surgery, Yokohama City University School of Medicine, Yokohama, Japan  Reprint requests: Hiroyuki Makita, MD, PhD, Department of Orthpaedic Surgery, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
No benefits or funds were received in support of the study. PII: S0883-5403(06)00256-7 doi:10.1016/j.arth.2006.02.157 © 2007 Elsevier Inc. All rights reserved. | |
|
FULL TEXT00256-7/journalimage?img=PIIS0883540306002567.gr1.lrg.gif&fig=fig1&kwhquery=&issn=0883-5403&ishighres=false&allhighres=false&free=yes','journalimage');)
00256-7/journalimage?img=PIIS0883540306002567.gr2.lrg.gif&fig=fig2&kwhquery=&issn=0883-5403&ishighres=false&allhighres=false&free=yes','journalimage');)
00256-7/journalimage?img=PIIS0883540306002567.gr3.lrg.gif&fig=fig3&kwhquery=&issn=0883-5403&ishighres=false&allhighres=false&free=yes','journalimage');)
00256-7/journalimage?img=PIIS0883540306002567.gr4.lrg.gif&fig=fig4&kwhquery=&issn=0883-5403&ishighres=false&allhighres=false&free=yes','journalimage');)