Effects of Age and Body Mass Index on the Results of Transtrochanteric Rotational Osteotomy for Femoral Head Osteonecrosis Surgical Technique

Transcription

1 75 Copyright 2011 by The Journal of Bone and Joint Surgery, Incorporated Effects of Age and Body Mass Index on the Results of Transtrochanteric Rotational Osteotomy for Femoral Head Osteonecrosis Surgical Technique By Yong-Chan Ha, MD, Hee Joong Kim, MD, Shin-Yoon Kim, MD, Ki-Choul Kim, MD, Young-Kyun Lee, MD, and Kyung-Hoi Koo, MD Investigation performed at the Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Seoul; the Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul; and the Department of Orthopaedic Surgery, Kyungpook National University College of Medicine, Daegu, South Korea The original scientific article in which the surgical technique was presented was published in JBJS Vol. 92-A, pp , February 2010 ABSTRACT FROM THE ORIGINAL ARTICLE BACKGROUND: Advanced-stage osteonecrosis and a large area of necrotic bone are known risk factors for failure of transtrochanteric rotational osteotomy of the hip in patients with osteonecrosis. The purpose of this study was to determine whether there are other risk factors for failure of this osteotomy. METHODS: One hundred and five patients (113 hips) underwent an anterior transtrochanteric rotational osteotomy for the treatment of femoral head osteonecrosis and were followed for a mean of 51.3 months postoperatively. Radiographic failure was defined as secondary collapse or osteoarthritic change. Multivariate analysis was performed to assess factors associated with secondary collapse and osteophyte formation. The Kaplan-Meier product-limit method was used to estimate survival. RESULTS: Secondary collapse occurred in twenty-seven hips (24%), and fourteen hips (12%) were converted to a total hip arthroplasty. At the time of the most recent follow-up, the hip scores according to the system of Merle d Aubigné et al. ranged from 6 to 18 points (mean, 15.8 points). Multivariate analysis showed that the stage of the necrosis (III or greater) (hazard ratio = 3.28; 95% confidence interval = 1.49 to 7.24), age of the patient (forty years or older) (hazard ratio = 1.08; 95% confidence interval = 1.02 to 1.14), body mass index ( 24 kg/m2) (hazard ratio = 1.19; 95% confidence interval = 1.03 to 1.38), and extent of the necrosis (a combined necrotic angle of 230 ) (hazard ratio = 1.08; 95% confidence interval = 1.04 to 1.11) were associated with secondary collapse. Seven of the eighty-six hips without collapse showed progression to osteoarthritis. The survival rate at 110 months was 63.4% (95% confidence interval = 51.1% to 75.7%) with total hip arthroplasty or radiographic failure as the end point and 56.0% (95% confidence interval = 44.6% to 67.4%) with total hip arthroplasty, radiographic failure, or loss to follow-up as the end point. CONCLUSIONS: Our study showed that age, body mass index, and the stage and extent of the osteonecrosis were determining factors for secondary collapse, unsatisfactory clinical results, and conversion to total hip arthroplasty. These factors should be considered when selecting patients for a transtrochanteric rotational osteotomy. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence. ORIGINAL ABSTRACT CITATION: Effects of Age and Body Mass Index on the Results of Transtrochanteric Rotational Osteotomy for Femoral Head Osteonecrosis (2010;92:314-21). Disclosure: The authors did not receive any outside funding or grants in support of this research or for the preparation of this work. Neither the authors nor any member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from any commercial entity. J Bone Joint Surg Am. 2011;93 Suppl 1:75-84 doi: /jbjs.j.01215

2 76 INTRODUCTION Transtrochanteric rotational osteotomy was introduced by Sugioka in 1972 as a form of joint-preserving surgery in femoral head osteonecrosis. This osteotomy moves the necrotic portion of the femoral head from the weight-bearing region to a non-weight-bearing region 1. The procedure has been selected as an alternative to total hip arthroplasty in some young patients. Several studies have reported various clinical outcomes and risk factors for failure of the osteotomy 2-5. Reported reasons for failure are nonunion of the osteotomy, postoperative fracture of the femoral neck, progression to collapse, and osteoarthritic change 3-5. Regarding the fixation devices used for transtrochanteric rotational osteotomy, Sugioka et al. originally used two or three large cancellous screws; however, this original fixation method was associated with complications, including progressive varus deformity, nonunion, femoral neck fracture, and prolonged hospital stay 6. Therefore, since 1999, we have used a 120º angled compression hip screw instead of cancellous screws. In the present report, we describe this technique in detail. SURGICAL TECHNIQUE Patient Positioning The patient is placed in the lateral decubitus position, on a standard operating-room table, with the pelvis aligned in a neutral position and stabilized with pad supports on the symphysis pubis and sacrum (Fig. 1). Fluoroscopy is used to confirm the position of the 120 angled compression hip screw during the operation. Skin Incision and Approach A Y-shaped skin incision is used. The posterior portion of the incision is begun at a point that is level with the posterior supe- Fig. 1 The patient is placed in the lateral decubitus position and the pelvis is secured with holding devices and pads. The Y-shaped skin incision is centered at the greater trochanter. The posterior portion of the incision is started at a point that is level with the posterior superior iliac spine and along a line parallel to the posterior edge of the greater trochanter. The incision is extended distally to the center of the greater trochanter and then to a point 10 to 15 cm distal to the greater trochanter, in line with the femoral shaft. The anterior portion of the incision is made from the greater trochanter to the anterior superior iliac spine.

3 77 Fig. 2 The gluteus maximus fascia is incised in line with the posterior portion of the skin incision, and the muscle fibers of the gluteus maximus are bluntly divided. Fibers of the fascia lata are divided in line with the anterior portion of the skin incision. The fat tissue covering the external rotators and the trochanteric bursa are removed to expose the sciatic nerve (arrow) along its course beneath the piriformis muscle and over the short external rotators distally. Fig. 3 An osteotomy of the greater trochanter is performed, and the trochanter is reflected proximally with the attached insertion of the gluteus medius and minimus to expose the superior aspect of the hip joint capsule. The gluteus medius and minimus are elevated sharply from the capsule of the hip joint. Then the insertion of the short external rotators on the proximal part of the femur is divided and reflected to expose the posterior aspect of the hip joint capsule. The quadratus femoris, superior gemellus, and inferior gemellus tendons are cut to expose the inferior portion of the joint capsule. The interval between the gluteus medius and vastus lateralis is developed to expose the anterior portion of the joint capsule and the reflected head of the rectus femoris.

4 78 rior iliac spine and along a line parallel to the posterior edge of the greater trochanter. It is then extended distally to the center of the greater trochanter and then to a point that is 10 to 15 cm distal to the greater trochanter, in line with the femoral shaft. The anterior portion of the incision runs from the greater trochanter to the anterior superior iliac spine (Fig. 1). The gluteus maximus fascia is incised in line with the posterior portion of the skin incision, and the gluteus maximus muscle fibers are bluntly divided, giving access to the gluteus medius and the external rotators of the hip. The fibers of the fascia lata are sharply divided in line with the anterior portion of the skin incision (Fig. 2). The length of the incision that is used depends on the patient s size and body mass index. The fat tissue covering the external rotators is removed, the trochanteric bursa is excised, and, with blunt dissection posteriorly, the sciatic nerve is exposed along its course beneath the piriformis muscle and over the short external rotators distally. The nerve should be protected during the operation (Fig. 2). Next, the greater trochanter is osteotomized between the gluteus medius and piriformis posteriorly, and between the gluteus medius and vastus lateralis anteriorly, with use of an oscillating saw. To expose the superior aspect of the hip joint capsule, the gluteus minimus is dissected from the hip capsule, and the gluteus medius and minimus muscles are retracted superiorly. Precise knowledge of the extracapsular anatomy of the medial femoral circumflex artery and its surrounding structures is essential to avoid iatrogenic damage of the artery during the osteotomy. The artery originates from the profunda femoris artery or the common femoral artery and passes between the pectineus medially and the iliopsoas tendon laterally along the inferior border of the obturator externus. Then, the main branch of the artery runs in the space between the quadratus femoris and the inferior gemellus. It crosses posterior to the tendon of the obturator externus and anterior to the tendons of the superior gemellus, the obturator internus, and the Fig. 4 After the complete exposure of the hip joint capsule, the joint capsule is incised circumferentially. The capsulotomy line is 1 cm away from the acetabular rim to protect the acetabular labrum and to obtain adequate rotation of the femoral head.

5 79 Fig. 5 A: The first transtrochanteric osteotomy is made about 10 mm distal to the intertrochanteric crest. On the osteotomized trochanteric surface, this osteotomy line should be perpendicular to the femoral neck. B: On the posterior femoral cortex, the line is inclined 20 from a line perpendicular to the femoral neck to place the femoral head in a varus position. The second osteotomy is made at the upper one-third of the lesser trochanter at 90 to the first osteotomy line. inferior gemellus. At the level of the tendon of the obturator externus, it travels superiorly and crosses anterior to the conjoint tendon of the gemellus inferior, obturator internus, and gemellus superior. It then perforates the joint capsule at the level of the gemellus superior 7 (Figs. 3 and 4). To expose the posterior aspect of the joint capsule, the tendon of the piriformis and the conjoint tendon of the gemellus superior, obturator internus, and gemellus inferior are transected 1 cm away from their trochanteric insertions, and then reflected posteriorly. To expose the inferior portion of the joint capsule, the quadratus femoris and obturator externus are cut. To avoid damage to the medial femoral circumflex artery, these two muscles should be cut within their substance, 2 cm away from their femoral insertions 7. When fatty tissue is encountered during the transection of the quadratus femoris muscle, care must be taken to avoid injury to the medial femoral circumflex artery that lies just beneath the fatty tissue. To expose the anterior portion of the joint capsule and the reflected head of the rectus femoris, the interval between the gluteus medius and vastus lateralis is developed (Fig. 3). Once complete exposure of the hip joint capsule has been obtained, the joint capsule is incised circumferentially. The capsulotomy line should be 1 cm away from the acetabular rim to avoid injury to the acetabular labrum and to obtain adequate rotation of the femoral head. The capsule should be grasped with the use of forceps and separated from the underlying femoral head to avoid injury to the femoral head cartilage during the capsulotomy (Fig. 4). The first transtrochanteric osteotomy should be made about 10 mm distal to the intertrochanteric crest. On the osteotomized trochanteric surface, the osteotomy line is perpendicular to the femoral neck. On the posterior femoral cortex, the line is inclined 20 from a line perpendicular to the femoral neck in order to place the femoral head in a varus position. The second osteotomy is made at the upper one-third of the lesser trochanter at 90 to the first osteotomy line in order to leave some bone attached to the distal fragment to support the proximal fragment after rotation (Fig. 5). The two lines of the transtrochanteric osteotomy are marked with a broad straight osteotome, and the osteotomy is performed with use of a reciprocating saw (Fig. 6). A Kirschner wire is placed in the proximal segment, from lateral to medial, in a plane perpendicular to the neck. The proximal fragment is then rotated anteriorly 90, with care taken to avoid excessive stretching of or damage to the medial femoral

6 80 Fig. 6 The two osteotomy lines are marked with a broad straight osteotome (A), and the osteotomy is performed with use of a reciprocating saw (B). circumflex vessels. After rotation of the proximal fragment, the segment is temporarily fixed with use of clamps or Kirschner wires (Fig. 7). The collapsed necrotic portion of the femoral head is moved anteroinferiorly away from the weight-bearing area after rotation of the proxi- Fig. 7 A Kirschner wire is placed in the proximal segment (A). The proximal fragment is rotated anteriorly 90 (arrow in B), with care taken to avoid excessive stretching of or damage to the medial femoral circumflex vessels. The rotated proximal segment is temporarily fixed with use of clamps or Kirschner wires (B).

7 81 Fig. 8 Intraoperative photographs showing that the collapsed necrotic portion of the femoral head (arrowheads) (A) has been moved anteroinferiorly away from the weight-bearing area after the rotation (B). mal segment (Fig. 8). Then the guide pin is positioned with use of a 120º fixed-angle guide that is anchored on the midportion of the lateral femoral cortex. The appropriate lag-screw length and reaming distance are then determined. After verifying the position and depth of the lag screw with image intensification in both the anteroposterior and mediolateral planes, the osteotomy is fixed with use of a 120 compression hip screw and plate (Solco, Seoul, South Korea) (Fig. 9). To reattach the trochanteric fragment, a number-sixteen stainless steel wire is used. A hole is drilled in the lateral femoral cortex below the abductor tubercle, and a hole is drilled in the superior portion of the osteotomized trochanter for the passage of vertical wires. Another hole is drilled 1 cm below the first trochanteric osteotomy line in the proximal part of the femur, and two holes are drilled in the anterior and posterior portions of the osteotomized trochanter for the passage of transverse wires. A wire is bent to create a U-shaped vertical wire. The two ends of the U-shaped vertical wire are passed through the hole in the lateral femoral cortex and the hole in the superior portion of the osteotomized trochanter to produce a wire loop at the lateral cortex. The two free ends are then passed in opposite directions through the loop in the lateral cortex. Two transverse wires are passed through the hole below the trochanteric osteotomy and then through the two holes in the anterior and posterior portions of the osteotomized trochanter (Fig. 10). The wires are then tightened and twisted with use of a Kirschner bow (Fig. 11). A closed suction drain is then inserted. It is removed

8 82 Fig. 9 After rotating the proximal fragment, the guide pin is positioned with use of a 120º fixed-angle guide that is anchored on the midportion of the lateral femoral cortex. After verifying the position and depth of the lag screw in both the anteroposterior and mediolateral planes, the osteotomy is fixed with use of a 120 compression hip screw and plate. Fig. 10 The trochanteric fragment is reattached with use of a number-sixteen stainless steel wire. A hole is drilled in the lateral femoral cortex and a hole is made in the superior portion of the osteotomized trochanter for the passage of vertical wires. Another hole is drilled 1 cm below the first trochanteric osteotomy line in the proximal part of the femur, and two holes are drilled in the anterior and posterior portions of the osteotomized trochanter for the passage of transverse wires. The two ends of the U-shaped vertical wire are passed through the hole in the lateral femoral cortex and the hole in the superior portion of the osteotomized trochanter. The two free ends are then passed in opposite directions through the loop in the lateral cortex. The two transverse wires are passed through the hole below the trochanteric osteotomy and then through the two holes in the anterior and posterior portions of the osteotomized trochanter.

9 83 Fig. 11 The wires are then tightened and twisted with use of a Kirschner bow. when the daily amount of drainage is <50 ml. POSTOPERATIVE CARE Three days after the operation, the patient is allowed to walk with protected weight-bearing with the use of crutches. The patient continues to use crutches for three to six months until there is radiographic evidence of osseous union of the osteotomy site. To evaluate possible injury to the medial femoral circumflex artery during the operation, a postoperative bone scan is performed within two weeks and perfusion to the femoral head segment is evaluated. CRITICAL CONCEPTS INDICATIONS: Transtrochanteric anterior rotational osteotomy is indicated for patients with postoperative osteonecrotic hip collapse without narrowing of the joint space or acetabular involvement (Ficat stages IIB and III) 8,9 ; patients younger than forty years of age with a painful hip; and patients with a large enough viable area (an arc of >120 between the central vertical line of the femoral head and the posterior margin of the necrotic portion on midsagittal magnetic resonance images). This osteotomy is also indicated for the treatment of Legg-Calvé-Perthes disease, insufficiency fractures of the femoral head, a slipped capital femoral epiphysis, and primary osteoarthritis of the hip with localized erosion in the weightbearing area. CONTRAINDICATIONS: The described procedure is not recommended for hips with extensive necrosis of the femoral head (an arc of 120 between the central vertical line of the femoral head and the posterior margin of the necrotic portion on midsagittal magnetic resonance images), patients with overall poor health owing to an underlying disease, and hips with severe osteoarthritic changes. Our study demonstrated that an age of more than forty years and a body mass index of 26 kg/m 2 predict secondary collapse after transtrochanteric anterior rotational osteotomy. Therefore, this osteotomy should be restricted to young patients with a low body-mass index. continued

10 84 CRITICAL CONCEPTS (CONTINUED) PITFALLS: A thorough understanding of the anatomy of the medial femoral circumflex artery is of critical importance for the safe performance of this procedure. The medial femoral circumflex artery can be identified in the space between the quadratus femoris and the obturator externus. During the performance of the capsulotomy, the retinacular vessels on the quadriceps femoris muscles should be preserved, and extreme care must be taken not to damage these vessels during the procedure. In addition, when the proximal fragment is rotated anteriorly, care should be taken to avoid excessive stretching and damage to the medial femoral circumflex vessels. AUTHOR UPDATE: The technique described in this paper differs from the original technique that was described by Sugioka 1. In terms of the skin incision used, we prefer a Y-shaped skin incision to a U-shaped incision, because it provides better exposures of the anterior and posterior portions of the hip joint capsule. Furthermore, the use of a 120º angled compression hip screw for fixation of the osteotomy prevents the complications (i.e., progressive varus deformity, nonunion, and femoral neck fracture) that can occur after fixation with cannulated screws. In addition, the use of the compression hip screw shortens the hospital stay and allows earlier rehabilitation. Yong-Chan Ha, MD Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Heukseokdong, Dongjak-gu, Seoul , South Korea Hee Joong Kim, MD Ki-Choul Kim, MD Young-Kyun Lee, MD Kyung-Hoi Koo, MD Department of Orthopaedic Surgery, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul , South Korea. address for K.-H. Koo: khkoo@snu.ac.kr Shin-Yoon Kim, MD Department of Orthopaedic Surgery, Kyungpook National University College of Medicine, 200 Dongduk-ro, Jung-gu, Daegu , South Korea REFERENCES 1. Sugioka Y. Transtrochanteric anterior rotational osteotomy of the femoral head in the treatment of osteonecrosis affecting the hip: a new osteotomy operation. Clin Orthop Relat Res. 1978;130: Koo KH, Song HR, Yang JW, Yang P, Kim JR, Kim YM. Trochanteric rotational osteotomy for osteonecrosis of the femoral head. J Bone Joint Surg Br. 2001;83: Dean MT, Cabanela ME. Transtrochanteric anterior rotational osteotomy for osteonecrosis of the femoral head. Long-term results. J Bone Joint Surg Br. 1993;75: Ikemura S, Yamamoto T, Jingushi S, Nakashima Y, Mawatari T, Iwamoto Y. Use of a screw and plate system for a transtrochanteric anterior rotational osteotomy for osteonecrosis of the femoral head. J Orthop Sci. 2007;12: Masuda T, Matsuno T, Hasegawa I, Kanno T, Ichioka Y, Kaneda K. Results of transtrochanteric rotational osteotomy for nontraumatic osteonecrosis of the femoral head. Clin Orthop Relat Res. 1988;228: Sugano N, Takaoka K, Ohzono K, Matsui M, Saito M, Saito S. Rotational osteotomy for non-traumatic osteonecrosis of the femoral head. J Bone Joint Surg Br. 1992;74: Gautier E, Ganz K, Krügel N, Gill T, Ganz R. Anatomy of the medial femoral circumflex artery and its surgical implications. J Bone Joint Surg Br. 2000;82: Ficat RP. Idiopathic bone necrosis of the femoral head. Early diagnosis and treatment. J Bone Joint Surg Br. 1985;67: Smith SW, Meyer RA, Connor PM, Smith SE, Hanley EN Jr. Interobserver reliability and intraobserver reproducibility of the modified Ficat classification system of osteonecrosis of the femoral head. J Bone Joint Surg Am. 1996;78: