Quality of Life Following Femoral Head-Neck Osteochondroplasty for Femoroacetabular Impingement

Beaulé, Paul E. MD, FRCSC; Le Duff, Michel J. MA; Zaragoza, Edward MD

Journal of Bone & Joint Surgery - American Volume: April 2007 - Volume 89 - Issue 4 - p 773–779
doi: 10.2106/JBJS.F.00681
Scientific Articles

Background: Femoroacetabular impingement has been recently described as a common cause of hip pain and labral tears in young adults. We evaluated the early clinical results and quality of life after osteochondroplasty of the femoral head-neck junction for the treatment of femoroacetabular impingement.

Methods: Thirty-seven hips in thirty-four patients with persistent hip pain and a mean age of 40.5 years underwent surgical dislocation of the hip and osteochondroplasty of the femoral head-neck junction for the treatment of camtype femoroacetabular impingement. All of the patients had had preoperative evidence of pathological changes in the labrum on imaging. The clinical course and the quality of life were assessed postoperatively.

Results: The mean score on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) increased from 61.2 points preoperatively to 81.4 points at a mean of 3.1 years postoperatively (p < 0.001), the mean University of California at Los Angeles (UCLA) activity score increased from 4.8 to 7.5 points (p < 0.001), the mean Short Form-12 (SF-12) physical component score increased from 37.3 to 45.6 points (p < 0.001), and the mean SF-12 mental component score increased from 46.4 to 51.2 points (p = 0.031). None of the hips underwent additional reconstructive surgery. There were no cases of osteonecrosis. Nine patients underwent screw removal from the greater trochanter because of persistent bursitis. Six of the thirty-four patients were dissatisfied with the outcome.

Conclusions: Cam-type femoroacetabular impingement is associated with insufficient concavity at the anterolateral head-neck junction and with pathological changes in the labrum. Osteochondroplasty of the femoral head-neck junction following surgical dislocation of the hip joint is safe and effective and can provide a significant improvement in the overall quality of life of most patients.

Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

1 Division of Orthopaedic Surgery, University of Ottawa, Ottawa Hospital General Campus, 501 Smyth Road, Suite 5004, Ottawa, ON K1H 8L6, Canada

2 Joint Replacement Institute, Orthopaedic Hospital, 2400 South Flower Street, Los Angeles, CA 90007

3 Department of Radiology, David Geffen School of Medicine at University of California at Los Angeles, 1250 16th Street, Santa Monica, CA 90404

Article Outline

Femoroacetabular impingement recently has been described as a common cause of hip pain in young adults1-3 and has been proposed as a cause of hip osteoarthritis2,4-6. Ganz et al. described the pathomechanism as dynamic repetitive abnormal contact between the femoral head-neck junction and the acetabular rim resulting in damage to the acetabular cartilage and tearing of the labrum1,2. There are two types of femoroacetabular impingement: the cam type, associated with an insufficient concavity or offset at the anterolateral head-neck junction1,3,7, and the pincer type, associated with acetabular overcoverage and acetabular retroversion8,9. Recently, Beck et al.6 found that a majority of patients have a mixed type of femoroacetabular impingement that presents with features of both the cam and the pincer type.

In 2001, Ganz et al.10 described a safe and effective technique to dislocate the hip joint surgically without risk of osteonecrosis. This approach allows the surgeon to correct the abnormal femoral head-neck junction and the abnormalities of the acetabular rim as well as address damage to the articular cartilage. Recent studies of this technique by Beck et al.11 and Murphy et al.12 showed encouraging early clinical results. The purpose of the present study was to report the short-term outcomes, as measured with validated health-related quality-of-life questionnaires as well as an activity score, following treatment of femoroacetabular impingement.

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Materials and Methods

Our institutional review board approved this study. Between 2001 and 2003, thirty-four patients (thirty-seven hips) with persistent hip pain secondary to femoroacetabular impingement were treated by the senior author (P.E.B.). There were eighteen men and sixteen women with an average age of 40.5 years (range, nineteen to fifty-four years). All patients had had hip pain, which was worsened by prolonged sitting and by activities of daily living, for more than three months. All had a positive impingement sign2,13 (i.e., pain with flexion, adduction, and internal rotation of the hip). The diagnosis of femoroacetabular impingement was confirmed with three-dimensional computed tomography, with an alpha angle of >50° considered to be abnormal3,7. The mean alpha angle was 65.6° (range, 51.0° to 95°). Three patients had a history of minor hip trauma. One patient had had previous hip arthroscopy with partial excision of the labrum. One patient had been treated as a child with in situ pinning of a slipped capital femoral epiphysis. No hip had evidence of acetabular dysplasia (a center-edge angle of <25°14-16) and/or arthritis (a Tönnis grade17 of >1).

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Clinical and Radiographic Evaluation

All patients completed preoperative and postoperative disease-specific and health-related outcome questionnaires. These included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)18, the University of California at Los Angeles (UCLA) activity scale19,20, and the mental and physical components of the Short Form-12 (SF-12)21. Radiographic examination included an anteroposterior pelvic view as well as a cross-table lateral view with the lower limb held in 15° to 20° of internal rotation22 (Fig. 1-A). Because we are reporting our early experience with this procedure, our anteroposterior pelvic radiographs were not standardized to control for the effect of pelvic tilt23; thus, any interpretation of acetabular retroversion was unreliable. Magnetic resonance imaging with gadolinium arthrography was performed for all patients24. It showed evidence of a labral tear at the anterosuperior quadrant in thirty-four hips and calcification within the labrum in three hips. A tear was diagnosed if the study demonstrated intrasubstance gadolinium signal (linear clefts or imbibitions of gadolinium contrast medium), gadolinium signal at the labrum-bone junction (labrum-bone separation), absence of a segment of the labrum, or a combination of those findings24. Three-dimensional computer tomography was performed on all hips to assess the alpha angle3,7. All patients also had an anteroposterior pelvic radiograph at the time of the latest follow-up. At the time of the surgical intervention, damage to the acetabular cartilage was characterized according to the criteria of Beck et al.11 (Table I).

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Surgical Technique

All thirty-seven hips underwent a surgical dislocation as described by Ganz et al.10. With the hip dislocated, the asphericity of the femoral head that corresponded to the area of impingement was well visualized (Figs. 1-B and 1-C). To correct the femoral head-neck offset, a spherometer gauge (Wright Medical Technology, Arlington, Tennessee) was used to determine the extent of osteochondroplasty to be performed with osteotomes and a small high-speed burr. Correction was deemed to be sufficient once the spherometer was congruent with the femoral head (Figs. 1-B and 1-C). The acetabulum was then examined to identify labral tears and delamination of the acetabular cartilage. All of the labral tears consisted of detachment of the intraarticular portion of the labrum from the acetabular cartilage but not from its attachment at the osseous rim. Consequently, only the intra-articular portion was débrided, with the majority of the labrum left intact.

When present, delaminated acetabular cartilage was débrided to a stable edge. Since this report represents the initial experience of the senior author, only two hips had surgical detachment of the labrum to remove a prominent acetabular rim and/or remove exposed subchondral bone secondary to a delaminated segment. In these two hips, the labrum was reattached with two or three suture anchors25.

Postoperatively, all patients used crutches for six weeks with partial weight-bearing, after which physical therapy was initiated and performed for a period of six to eight weeks. Physical therapy consisted of stretching and range-of-motion exercises as well as a muscle-strengthening program.

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Statistical Analysis

The difference between the preoperative and follow-up hip scores was analyzed with paired Student t tests. Significance was determined to be p < 0.05.

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Results

Intraoperative

Of the thirty-seven hips that underwent surgery, two were categorized as type 3 according to the criteria described by Beck et al.11; twenty, as type 4; and six, as type 5 (Table I). The remaining nine hips had normal-appearing cartilage.

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Clinical

At a mean of 3.1 years (range, 2.1 to 5.0 years) postoperatively, none of the patients has undergone additional reconstructive hip surgery. Six patients (three women and three men) had an unsatisfactory outcome with no clinical improvement and/or worsening of the WOMAC score. The mean postoperative outcome scores in the whole group of patients significantly improved compared with the preoperative scores. The mean WOMAC score (and standard deviation) improved from 61.2 ± 20 to 81.4 ± 16 points (p < 0.001). The mean UCLA activity score improved from 4.8 ± 1.9 to 7.5 ± 2.4 points (p < 0.001) (Fig. 2). The mean SF-12 physical and mental component scores improved from 37.3 ± 10.4 to 45.6 ± 10.5 points (p < 0.001) and from 46.4 ± 11.4 to 51.2 ± 11.3 points (p = 0.031), respectively. Eleven of the thirty-four patients underwent surgical interventions on the contralateral hip.

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Reoperations

One patient had failure of the trochanteric fixation at three weeks postoperatively; this required refixation, which was followed by uneventful healing. One patient had Brooker26 Grade-IV heterotopic ossification, which required excision at ten months postoperatively. At the time of the latest follow-up, twenty-six months postoperatively, he had returned to full participation in activities with no pain. In nine hips, painful internal fixation devices in the greater trochanter created persistent bursitis, which necessitated removal of the screws at a mean of eight months (range, six to fourteen months) postoperatively. All patients became asymptomatic and returned to full activities after the screws were removed.

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Poor Outcomes

Six patients (seven hips) had an unsatisfactory outcome (Table II). One hip had undergone a previous arthroscopic procedure and, at the time of the surgical dislocation, it was noted that the labrum between the 12 o'clock and 2 o'clock positions had been excised. Another patient had had in situ pinning of a slipped capital femoral epiphysis as a child and was noted to have substantial (Beck type-4) delamination of the acetabular cartilage at the time of the index operation. Four other hips also had Beck type-4 damage to the acetabular cartilage. One patient had no objective evidence of a cartilage injury. Overall, five of the six patients (six of the seven hips) with a poor outcome had Beck type-4 cartilage damage. However, we found no correlation (r = –0.12, p > 0.05) between cartilage damageand the clinical outcome since nineteen patients (twenty hips) with a good outcome had either type-4 or 5 cartilage damage as well.

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Discussion

This study demonstrated that femoral head-neck offset for the treatment of cam-type femoroacetabular impingement results in early improvement in both disease-specific and health-related outcomes and confirmed the previous findings of Beck et al.11 and Murphy et al.12. Notably, the majority of previous authors25,27-29 who evaluated nonarthritic hip pain and its treatment used outcome tools such as the Merle d'Aubigné30 or Harris hip score31, which were developed for the assessment of the results of total hip arthroplasty. Although these hip scores adequately describe a patient's physical ability after total hip arthroplasty, they do not necessarily provide a full assessment of the patient's quality of life as general health-related quality-of-life measures do32-34. To our knowledge, the only other study in which global and disease-specific health-related quality-of-life measures were used to evaluate patients with nonarthritic hip pain was that by van Bergayk and Garbuz35, who assessed patients with hip dysplasia. As was the case in our study, they noted that patients were substantially incapacitated with regard to their ability to perform activities of daily living despite having no signs of advanced hip arthritis. By using the UCLA activity scale, we also documented the active use of the hips by these patients36,37. This is especially relevant since the capacity of these younger patients to participate in sports activities improved significantly, with 56% having a UCLA activity score of ≥8 points.

Although labral tears per se were the initial focus of interest in the treatment of prearthritic hip pain38-40, there is a growing body of evidence that, in many patients, structural osseous abnormalities are the cause of the labral tears41,42 and that acetabular cartilage damage is also present6,8,11,38,43,44. McCarthy et al.43 noted damage to the acetabular cartilage adjacent to a labral tear in 62.8% (273) of 435 hips and described it as an erosion and/or a flap. In a more recent report on the treatment of femoroacetabular impingement, Beck et al.11 noted that eighteen of nineteen hips with pathological changes in the labrum had associated damage to the acetabular cartilage. In our study, damage to the acetabular cartilage was found in twenty-seven of thirty-seven hips, including six of the seven patients with an unsatisfactory outcome. Although damage to the acetabular cartilage represents an advanced disease state, it cannot fully account for the poor outcomes in our series, since nineteen patients (twenty hips) with a good outcome also had some degree of damage to the acetabular cartilage. Thus, other factors such as unrecognized acetabular retroversion may have played a role. Our current inability to properly assess the overall health of articular cartilage requires better imaging techniques such as magnetic resonance imaging with gadolinium arthrography45,46 or delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC)47 to detect cartilage lesions earlier in the disease process and enable physicians to provide more adequate counsel to patients with respect to the longevity of their hip joint.

Another unresolved issue in the management of femoroacetabular impingement is how to treat the associated delamination of the acetabular cartilage in the presence of pathological changes in the labrum. Currently, there are no specific guidelines in terms of how much of the acetabular floor can be left exposed once the delaminated segment has been removed or whether labral refixation after removal of exposed subchondral bone substantially improves the ultimate outcome. Recently, Espinosa et al.25 reported that the results of procedures in which as much of the intact labrum as possible had been preserved were superior to those of labral resection. In our series, none of the patients who had a poor outcome had had labral refixation. However, despite these limitations in our treatment, 82% (twenty-eight) of our thirty-four patients had improvement after osseous correction and partial labral débridement although there is a general consensus that preservation of a healthy labrum is beneficial to hip function25,43,48,49. Additional research is needed to better define the natural history of this osseous dysmorphism as well as to determine whether correction of this deformity alters the natural history of femoroacetabular impingement4,50.

Although our early clinical results are very encouraging, ten patients required a reoperation that was directly related to the surgical dislocation approach (e.g., screw removal or a reoperation because of failed trochanteric fixation). Consequently, we hope that in the future this condition can be treated with less-invasive techniques, such as hip arthroscopy51 or limited anterior hip arthrotomy52. Also, with improved imaging techniques to assess the health of articular cartilage, earlier diagnosis should allow more timely surgical intervention prior to the development of irreversible chondral degeneration. ▪

Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. One or more of the authors, or a member of his or her immediate family, received, in any one year, payments or other benefits in excess of $10,000 or a commitment or agreement to provide such benefits from a commercial entity (Wright Medical Technology, Inc., Arlington, Tennessee). No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.

Investigation performed at the Department of Orthopaedic Surgery, UCLA/Orthopaedic Hospital, Los Angeles, California, and the University of Ottawa, Ottawa, Ontario, Canada

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