Anterior femoroacetabular impingement after periacetabular osteotomy. Clin Orthop Relat Res. 1999;93-99. [PMID: 10379309 DOI: 10.1097/00003086-199906000-00012]

Lessons learned after more than 250 periacetabular osteotomies

The Bernese periacetabular osteotomy (PAO) has become the procedure of choice in many centers for the treatment of young patients with symptomatic hip dysplasia in the absence of severe secondary arthrosis. This article concerns our institution's "learning curve" with this procedure and focuses on patient selection, exposure, technical aspects of performing the bone cuts, mobilizing the fragment, and obtaining proper correction.

Effect of pelvic tilt on acetabular retroversion: a study of pelves from cadavers

Pelvic inclination is difficult to control on a standard radiograph of the pelvis and has a direct influence on the appearance of acetabular version. By defining the normal range of the distance between the symphysis and the sacrococcygeal joint on 86 standard anteroposterior radiographs of pelves a technique was developed to evaluate pelvic inclination. A statistically significant correlation between this distance and pelvic inclination was shown in four cadaver pelves. Acetabular retroversion signs (cross-over, posterior wall signs) were evaluated on normal pelves from cadavers (two females, two males) after mounting on a holding device and wire marking of the acetabular rims. Radiographs were taken 3 degrees stepwise through the range of 9 degrees inclination to 12 degrees reclination. At the neutral position, two acetabula appeared with both positive retroversion signs compared with none at 6 degrees reclination. At 9 degrees pelvic inclination all acetabula had both signs. Retroversion signs were significantly more pronounced and found at lower pelvic tilt angles in the pelves from males than from females. Evaluation of pelvic inclination will help to decrease measurement errors in assessment of acetabular orientation and femoral head coverage. This will be valuable in preoperative planning of reorientation procedures.

Kotz and Ganz osteotomies in the treatment of adult acetabular dysplasia

In hips with acetabular dysplasia, we performed Kotz osteotomy (group 1) in 22 hips (20 patients; mean age 24.3 years) and Ganz osteotomy (group 2) in 23 hips (22 patients; mean age 23.1 years). Group 1 was followed 83.3 (56-112) months and group 2 40.9 (24-66) months. In group 1, Harris hip score improved from average 74.9 to 86.9, mean center edge (CE) angle from -4.5 degrees to 30.3 degrees, and mean vertical center edge (VCE) angle from 5.3 degrees to 36.2 degrees. In group 2, Harris hip score improved from average 76.6 to 91.1, mean CE angle from -5.9 degrees to 32.0 degrees, and mean VCE angle from 5.0 degrees to 41.3 degrees. Using Pauwels criteria, regression was observed in 12 hips in group 1 and one progressed. In group 2, 15 hips showed regression and three progressed. In patients treated with Ganz osteotomy, the complication rate was higher and the complications more serious than in patients treated with Kotz osteotomy. Most complications were, however, seen among the first ten patients treated with Ganz osteotomy. Although we detected no significant difference between the two groups in terms of clinical and radiological findings, we believe the outcome to be slightly better after a properly performed Ganz osteotomy.

Rationale of osteotomy and related procedures for hip preservation: a review

Most osteoarthrosis of the hip results from chronic abnormal hip mechanics, often associated with instability, impingement, or combinations of instability and impingement. The etiology of the mechanical problems in many hips is a surgically treatable anatomic abnormality, often a developmental deformity (dysplasia, Perthes disease, slipped epiphysis, femoral or acetabular retroversion, or reduced head-neck offset). The rationale of mechanically-based measures to prevent or treat osteoarthrosis assumes the following: (1) correctable mechanical overload is a major etiologic factor in osteoarthrosis; and (2) relief of the mechanical overload can prevent or improve osteoarthrosis. The success of such mechanically-based joint-preserving measures depends largely on the completeness with which the joint-preserving treatment normalizes the mechanical environment of the hip. A limiting factor often is the amount of irreversible articular damage that is present at the time treatment is begun.

Surgical treatment of developmental dysplasia of the hip in adults: I. Nonarthroplasty options

Hip dysplasia is a developmental disorder that results in anatomic abnormalities leading to increased contact pressure in the joint and, eventually, coxarthrosis. However, many patients with hip dysplasia become symptomatic before the development of severe degenerative changes because of abnormal hip biomechanics, mild hip instability, impingement, or associated labral pathology. Several nonarthroplasty treatment options are available. Because the primary deformity is mostly acetabular, for many patients, a reconstructive osteotomy that restores more nearly normal pelvic anatomy is preferable. The Bernese periacetabular osteotomy is presently favored because it provides good correction while creating little secondary pelvic deformity or destabilizing the pelvis. Proximal femoral osteotomy is occasionally needed as a complement to pelvic osteotomy and may also be indicated as an isolated procedure when most deformity is located on the femoral side (coxa valga subluxans). Arthroscopy can be beneficial when symptoms seem to be related only to labral tears or loose bodies in the absence of severe structural abnormalities about the hip. Fusion and resection arthroplasty are rarely indicated and are reserved for occasional patients who are not candidates for total hip replacement or other procedures but who complain of refractory hip pain.

Retroversion of the acetabular dome after Salter and triple pelvic osteotomy for congenital dislocation of the hip

Retroversion of the acetabular dome has been associated with hip pain and osteoarthritis in several studies. Nevertheless, this acetabular alignment received little attention when studying the radiological outcome of pelvic osteotomies in childhood. We therefore reviewed the charts and X-rays of 73 patients with congenital dislocations, who underwent 97 pelvic osteotomies in childhood. We focussed our attention on anterior overcoverage or retroversion of the acetabular dome, respectively. Eighty-six Salter and 11 LeCoeur osteotomies were performed on patients with a mean age of 4.8 years. The mean age at last X-ray documentation was 16.5 years. The version of the acetabular dome was estimated qualitatively from the relationship of the anterior and posterior border to each other and measured semiquantitatively using templates developed by Hefti. According to Lequesne's criteria 94% of the hips were normal or borderline at maturity. A retroverted acetabular dome was present in 27% and averaged -15 degrees. It was more frequent (60% versus 24%) and more pronounced (-16 degrees versus +5 degrees) after Le Coeur's than after Salter's osteotomy and in the residually dysplastic hips (83% versus 22%; -15 degrees versus +3 degrees). It is suggested that anterior overcoverage of the femoral head results from ignorance, when choosing the type and performing the pelvic osteotomy, of where coverage needs to be improved in an individual hip. We question the long-term outcome of these hips because such rotational misalignment has been suggested to be associated with early hip pain and osteoarthritis. In order to avoid such misalignment, preoperative evaluation of where coverage needs to be improved in an individual hip and efforts for better intraoperative control of acetabular reorientation should be made.

Cross-Table Lateral Radiographs for Screening of Anterior Femoral Head-Neck Offset in Patients with Femoro-Acetabular Impingement

One theory for the aetiology of osteoarthrosis of the hip is the impingement of the anterior femoral neck against the acetabulum in flexion. The reduced femoral head-neck offset not visible on AP-radiography is implicated in this impingement. The anterior part of the head-neck region is well visualised on cross table lateral radiographs. A retrospective analysis of the offset using cross table lateral radiographs was therefore performed on twelve symptomatic and ten asymptomatic hips. The anterior offset (AOS) was defined as the difference in radius between the anterior femoral head and the anterior femoral neck. The offset ratio (OSR) was defined as the AOS divided by the femoral head diameter. The AOS was 11.6 ± 0.7 mm in the asymptomatic group and 7.2 ± 0.7 mm in the symptomatic group, which was statistically significantly different (p=0.0006). The OSR was 0.21 ± 0.03 in the asymptomatic group and 0.13 ± 0.05 in the symptomatic group, which was also statistically significantly different (p=0.0004). Cross-table lateral radiographs of the hip are useful for screening patients complaining of anterior femoro-acetabular impingement symptoms, as their anterior femoral head-neck offset may be smaller.

Bernese periacetabular osteotomy

Seventy-five symptomatic dysplastic hip joints (63 patients) were treated with the Bernese periacetabular osteotomy during a period of 44 months. The mean patients' age was 29 years (range, 13-56 years) and the female:male ratio was 3.4:1. Group III dysplasia according to Severin was seen in 50% and Group IV dysplasia was seen in 44% of the patients. Osteoarthritis was present in 58% of the patients. Followup was obtained at a mean of 11.3 years (range, 10-13.8 years) in 71 hip joints (95%). Radiographic measurements of the lateral center edge angle, anterior center edge angle, acetabular index, lateralization of the femoral head, and intactness of Shenton's line showed a high correction potential of this type of osteotomy. In 58 patients (82%) the hip joint was preserved at last followup with a good to excellent result in 73%. Unfavorable outcome was significantly associated with higher age of the patient, moderate to severe osteoarthritis at surgery, a labral lesion, less anterior coverage correction, and a suboptimal acetabular index. Major complications were encountered in the first 18 patients including an intraarticular cut in two, excessive lateralization in one, secondary loss of correction in two and femoral head subluxation in three patients.