Efficacy of Surgery for Femoroacetabular Impingement A Systematic Review
Background: Recent case studies on the surgical treatment of femoroacetabular impingement (FAI) have introduced a large amount of clinical data. However, there has been no clear consensus on its efficacy.
Hypothesis: The current literature can be clarified to address 4 questions: (1) Does treatment for FAI succeed in improving symptoms? (2) In which subset of patients should treatment for FAI be avoided? (3) Is labral refixation superior to simple resection? (4) Does treatment for FAI alter the natural progression of osteoarthritis in this group of typically young patients?
Study Design: Systematic review.
Methods: Twenty-three reports of case studies on the surgical treatment of FAI were identified and a systematic review was conducted. Data from each study were collected to answer each of the 4 focus questions.
Results: This review of 970 cases included 1 level II evidence trial, 2 level III studies, and 20 level IV studies. Based on patient outcome scores and effect size, all studies demonstrated improvement of patient symptoms. Up to 30% of patients will eventually require total hip arthroplasty; those patients with Outerbridge grade III or IV cartilage damage seen intraoperatively or with preoperative radiographs showing greater than Tonnis grade I osteoarthritis will have worse outcomes with treatment for FAI. Only 2 studies directly compared labral refixation with labral debridement. Several studies reported postoperative osteoarthritis findings; only a minority of these patients had progression of their osteoarthritis.
Femoroacetabular impingement as the cause of primary idiopathic osteoarthritis in young patients is a relatively new concept. Therapeutic techniques, although well described, are still in their formative stages. This systematic review of available literature was designed to address 4 clinically important questions: First, does treatment for FAI succeed in improving patient symptoms? By both outcome scores and effect size, both arthroscopic and open treatment methods for FAI significantly improved mean postoperative scores. Second, in which patients should standard treatment for FAI be avoided? Although mean outcome measures invariably improve, not all patients have satisfactory results. Between 0% and 30% of patients eventually required THA,5,22,25,26,30 and 0% to 31.2% of patients were dissatisfied with the procedure or had no improvement of their pain. Outerbridge grade III or IV cartilage injury seen intraoperatively and osteoarthritis greater than Tonnis grade I on preoperative radiographs were associated with poorer outcomes. Third, is labral refixation superior to labral resection? The studies examined varied in their treatment of labral injury. Only Espinosa et al12 and Laude et al23 directly compared labral refixation with simple resection and debridement. The former study found that hip function scores, pain scores, and delay of radiographic progression of osteoarthritis improved more with labral refixation. The latter study demonstrated no significant difference in outcome, but did note a tendency for higher outcome scores with labral refixation. Last, does treatment for FAI affect the progression of osteoarthritis? Because all case series were relatively recent and degenerative joint disease is generally a gradual process, it was difficult to elucidate the effect of surgical correction of FAI on the progression of osteoarthritis with radiographic imaging. In the studies that reported osteoarthritic radiographic change, only a minority of the patients had progression of their disease.
There remain many gaps in the available literature reporting treatment of FAI and most studies have relatively limited follow-up. In addition to a lack of high level of evidence studies, there has yet to be a direct comparison between open and arthroscopic methods. When treatment of FAI was compared with simple arthroscopic labral debridement and subchondral microfracture, Bardakos et al2 found excision of the impingement lesion produced higher postoperative scores and more good to excellent results. Bedi et al6 examined the outcomes of open and arthroscopic treatment of labral tears and FAI in a systematic review and found insufficient evidence to support open surgical dislocation, the historic gold standard, as a superior procedure.
The findings here are in agreement with the general conclusions by Bedi et al6 that both open and arthroscopic procedures can achieve satisfactory clinical outcomes. The varying outcome measures used across the literature provide a challenge in assessing the true value of each technique in reducing patient symptoms. The optimal management of severe acetabular cartilage lesions in the context of FAI is unknown. Patients with advanced osteoarthritic change as shown on preoperative radiographs will likely benefit less from treatment of FAI. The true extent of chondral lesions is difficult to assess preoperatively, even with MRA. Magnetic resonance imaging has been shown to be only 22% sensitive for cartilage delamination.1 Identifying these patients and developing definite contraindications to the treatment of FAI will be necessary to significantly improve success rates.
There is now a general consensus that labral preservation and restoration are beneficial; this shift is evident in the comparative study by Espinosa et al12 in which their 2 cohorts were a result of evolving methods rather than intentional randomization. Studies with higher level of evidence are needed before labral refixation is likely to be widely adopted. The longest mean follow-up, 5.2 years, was reported by Murphy et al25 in a study that included techniques now considered suboptimal.26 Clearly, longer-term results with large cohorts are needed to formulate specific evidence-based recommendations and to determine whether treatment for FAI alters its natural course. Bardakos and Villar3 found that 65% of patients with an untreated pistol-grip deformity and Tonnis grade I or II degenerative changes had progression of osteoarthritis after 10 years.
Early evidence in the treatment of FAI has shown that hip function and pain are improved in the majority of patients. Advanced chondral lesions and osteoarthritic change are associated with worse patient outcome, but the full extent of cartilage defects is difficult to assess preoperatively. Preliminary results support labral refixation, and it is too soon to conclude whether treatment of FAI can delay or halt the progression of osteoarthritis.