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Arthroscopic Labral Repair Versus Selective Labral Debridement in Female Patients With Femoroacetabular Impingement: A Prospective Randomized Study
Arthroscopic Labral Repair Versus Selective Labral Debridement in Female Patients With Femoroacetabular Impingement: A Prospective Randomized Study Aaron J. Krych, M.D., Matthew Thompson, M.D., Zak Knutson, M.D., Joanna Scoon, B.A., and Struan H. Coleman, M.D.
Purpose: The purpose of this prospective randomized study was to compare the outcomes of arthroscopic labral repair and selective labral debridement in female patients undergoing arthroscopy for the treatment of pincer-type or combined pincer- and cam-type femoroacetabular impingement. Methods: Between June 2007 and June 2009, 36 female patients undergoing arthroscopic hip treatment for pincer- or combined-type femoroacetabular impingement were randomized to 2 treatment groups at the time of surgery: labral repair or labral debridement. The repair group comprised 18 patients with a mean age of 38; the debridement group comprised 18 patients with a mean age of 39. All patients underwent the same rehabilitation protocol postoperatively. At a minimum of 1 year, all patients were assessed using a validated Hip Outcome Score (HOS) to determine hip function, and also completed a simple subjective outcome measure. Results: All 36 patients were available for follow-up at an average time of 32 months (range, 12 to 48). In both groups, HOSs for activities of daily living (ADL) and sports improved significantly from before surgery to the final follow-up (P < .05). The postoperative ADL HOS was significantly better in the repair group (91.2; range, 73 to 100) compared with the debridement group (80.9; range, 42.6 to 100; P < .05). Similarly, the postoperative sports HOS was significantly greater in the repair group (88.7; range, 28.6 to 100) than in the debridement group (76.3; range, 28.6 to 100; P < .05). Additionally, patient subjective outcome was significantly better in the labral repair group (P ¼ .046). Conclusions: Arthroscopic treatment of femoroacetabular impingement with labral repair in female patients resulted in superior improvement in hip functional outcomes compared with labral debridement. In addition, a greater number of patients in the repair group subjectively rated their hip function as normal or nearly normal after surgery compared with the labral debridement group. Level of Evidence: Level I, prospective randomized study.
F
emoroacetabular impingement (FAI) is a clinical syndrome associated with abnormalities of the shape and orientation of the hip causing conflict between the femur and acetabulum that can lead to pain, dysfunction, and early osteoarthritis.1,2 This aberrant, repetitive impact is the result of a mis-shapen
From the Department of Orthopedic Surgery (A.J.K.), Mayo Clinic, Rochester, Minnesota; Drisko, Fee & Parkins Orthopedics (M.T.), Independence, Missouri; Oklahoma Sports and Orthopedics Institute (Z.K.), Norman, Oklahoma; and Department of Orthopedic Surgery (J.S., S.H.C.), Hospital for Special Surgery, New York, New York, U.S.A. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received October 24, 2011; accepted July 20, 2012. Address correspondence to Aaron J. Krych, M.D., Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, U.S.A. E-mail: [email protected] Ó 2013 by the Arthroscopy Association of North America 0749-8063/11694/$36.00 http://dx.doi.org/10.1016/j.arthro.2012.07.011
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femoral head or neck (cam impingement), a malrotated or overly deep acetabulum (pincer impingement), or a combination of the two.3,4 Cam-type FAI is characterized by chondrolabral delamination on the acetabulum.1,2 Pincer impingement often results in repetitive damage to the labrum, sometimes causing a progressively diminutive and ossified labrum, with damage to the femoral headeneck junction.5,6 There are several reports of successful short-term outcomes after labral debridement in nonarthritic hips,7,8 as well as labral refixation/repair.6,9-11 Nevertheless, few studies have compared the effects of labral repair and labral debridement on functional outcome after hip surgery to treat FAI. In 2006, Espinosa et al. retrospectively compared open labral resection with labral refixation in association with treatment of FAI and reported improved patient outcomes and less osteoarthritis in patients having labral refixation.12 Similarly, in 2009, Larson et al. retrospectively examined their results of arthroscopic labral debridement versus labral repair
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 29, No 1 (January), 2013: pp 46-53
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Enrollment
Assessed for eligibility (n = 41) Excluded (n =5) Refused to participate (n =5)
Allocated to labral repair (n =18)
Follow up
Allocation
Randomized (n =36)
12-month follow-up (n = 18)
Analysis
during the management of FAI and reported superior outcomes in the group treated with labral repair13; they recently published the midterm results for these patients.14 However, both these studies were retrospective and compared a labral repair group with a historical control labral excision group. The main limitation of a historical control group is that significant improvements have occurred in the understanding of and technical advances in treating FAI, introducing confounding variables that could have resulted in the greater improvement in the patients who underwent labral repair. To our knowledge, there are no prospective, randomized studies or even comparative studies during the same period assessing labral debridement versus repair, in either open or arthroscopic treatment of FAI. Therefore, we designed a prospective randomized study of labral repair versus selective labral debridement in association with arthroscopic treatment of either pincer-type or combined pincer- and cam-type FAI. In this study, males were excluded as they tend to have higher alpha angles, indicating more of a camtype FAI,11,15,16 and it would be difficult to assess postoperative improvement attributed to treatment of the labrum. The purpose of this study was to determine if (1) functional outcome was superior in patients treated with labral repair compared with those who underwent selective labral debridement as measured with the validated Hip Outcome Score (HOS), and (2) subjective patient outcome was better in patients treated with labral repair than in those treated with selective labral debridement. We hypothesize that even at short-term follow-up, labral repair would lead to improved hip function scores and patient subjective outcomes when compared with labral debridement in the context of arthroscopic treatment of FAI.
Analyzed (n =18)
Allocated to selective labral debridement (n =18)
12-month follow-up (n = 18)
Analyzed (n =18)
Fig 1. CONSORT diagram showing the flow of participants through each stage of this randomized trial.
Design This randomized clinical trial was conducted from June 2007 through June 2009. Forty-one consecutive female patients with pincer- or combined-type FAI were identified as meeting the criteria, and 36 of those patients agreed to enroll in this trial (Fig 1). All patients gave written consent to participate in the study, and the study was approved by our institutional review board. Data were collected as part of our institution’s prospective hip registry.
pincer-type FAI. Radiographic evidence consisted of the presence of relative acetabular retroversion on a true anteroposterior plain pelvic radiograph, as indicated by a cross-over sign and prominent ischial spine sign; coxa profunda; acetabular protrusion; or a pincer divot at the femoral neck headeneck junction.17 In addition, the presence of labral tear/pathology was required on magnetic resonance imaging (MRI). The presence of a cam lesion was also noted, but did not exclude patients from the study as long as pincer-type FAI coexisted. Cam impingement was defined as an alpha angle greater than 45 on an oblique radiograph. 17 In most cases, an intra-articular injection of lidocaine was used to confirm the diagnosis. Exclusion criteria included pure cam-type FAI, as management of labral lesions in this setting does not necessarily require rim trimming.3,4 Males were excluded as they tend to have higher alpha angles, indicating more of a cam-type FAI,11,15,16 and it would be difficult to assess postoperative improvement attributed to treatment of the labrum. Other exclusion criteria included previous hip surgery, Tonnis grade 2 osteoarthritis,18,19 hip dysplasia based on radiographic evidence of a Wiberg lateral center edge angle less than 25 ,17,20 and patient age less than 18.
Inclusion Criteria Patients were eligible for the study if they were female, greater than 17 years of age, and diagnosed with either pincer-type or combined-type (coexistent pincerand cam-type) FAI. The diagnosis of pincer-type FAI was made on the basis of history, positive impingement signs on examination, and radiographic evidence of
Randomization and Blinding After enrolling, patients reported to the preoperative area on the day of surgery. They were then transferred to the operating room and, prior to placement of hip traction, were randomized to either labral repair or debridement. Randomization was carried out by opening one of 36 sealed, opaque envelopes assigning
Methods
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patients to receive either labral repair or debridement. The surgeon and patient were not blinded to treatment after the procedure. Surgical Procedure All 36 arthroscopic hip surgeries were performed by the senior author, an experienced hip arthroscopist (S.H.C.). Patients were positioned on a modified traction table and subjected to 25 to 50 pounds of traction to distract the operative hip. Three standard arthroscopy portals were used during the procedure: the anterolateral portal, the midanterior portal, and the distal anterolateral accessory portal. We use the landmarks established for safe portals, as described by Robertson and Kelly.21 Diagnostic arthroscopy was performed first to evaluate the labrum and articular cartilage. A capsulotomy was performed between the anterolateral and midanterior portals to achieve increased maneuverability within the hip joint. In the labral repair group, the soft tissue and capsule were removed using a cautery device to expose the pincer lesion (Fig 2). The labrum was left attached to the transitional fibers of the acetabular cartilage. Under fluoroscopic guidance, the portion of the anterior rim that was causing overcoverage was removed using a 5.5-mm burr (Fig 3). The labrum was then rolled back to the bone and repaired to the rim of the acetabulum using multiple suture anchors (Fig 4). For labral repair, a cannula was placed through a working midanterior (for working more medially) or anterolateral (for working more laterally) portal. A single-loaded PEEK suture anchor was then placed through the distal anterolateral accessory portal to create a more cephalad angle to avoid penetration of the acetabulum. A sharp tissue penetrator was then used through the cannula in either the midanterior or anterolateral portal to pass the nonabsorbable suture from the suture anchor using an intrasubstance stitch through the labrum. This was then tied using an arthroscopic sliding knot, and the ends were trimmed. An average of 3.1 suture anchors were used per repair (range, 2-4). In the labral debridement group, selective labral debridement was performed with preservation of as much stable labrum as possible to retain a functional seal between the labrum and the femoral head (Fig 5). The pincer lesion was then visualized without separation of the labrum from the acetabulum, and under fluoroscopic guidance, the portion of the anterior rim that was causing overcoverage was removed using a 5.5-mm burr. In all cases, the remaining labrum was stable to probing and no unstable labral tissue was left behind. Next, the traction was released and the hip was flexed approximately 40 . A longitudinal cut was made in the capsule along the femoral neck to evaluate the headeneck junction for the presence of a cam lesion. If a cam lesion was identified, a 5.5-mm burr was used to
Fig 2. Arthroscopic views of a left hip through the midanterior portal. (A) The pincer lesion is visualized superior to the labrum, which has been exposed by careful delineation of the labrum using an arthroscopic elevator and cautery device. (B) After resection of the pincer lesion and subanterior inferior iliac spine area. (A, acetabulum; AIIS, anterior inferior iliac spine; DP, debrided pincer; L, labrum; P, pincer lesion.)
resect the lesion. Fluoroscopy was used to guide the resection of the femoral neck. After removal of the cam lesion, the capsule was repaired using interrupted permanent suture. The portals were closed and a sterile dressing was applied. In both groups, 3 patients underwent only rim reduction for pincer-type impingement, whereas 15 patients underwent additional femoral neck osteochondroplasty for combined cam- and pincer-type impingement. Postoperative Care All patients were managed with the same postoperative pain regimen and rehabilitation protocol.
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Fig 4. Arthroscopic views of a right hip through the anterolateral portal. (A) The pincer lesion has been debrided and a suture anchor is being inserted through the midanterior portal. (B) The labrum has been repaired to the superior rim of the acetabulum with a vertical mattress intrasubstance suture configuration. Fig 3. Intraoperative fluoroscopic images of a left hip. (A) Anteroposterior view of the hip showing the lateralized anterior wall of the acetabulum (outlined in yellow) relative to the more medial posterior wall (outlined in blue). This radiographic finding is consistent with the pincer lesion seen intraoperatively. (B) Same AP view of the hip after resection of the pincer lesion, correcting the anterior overcoverage.
Postoperatively, patients were placed on crutches for 2 weeks with foot-flat partial weight bearing. Passive motion was started immediately. Patients were restricted from passive hip rotation for 4 weeks. A specific hip rehabilitation protocol was initiated between postoperative days 7 and 10. Assessment of Hip Function All patients completed a self-administered HOS questionnaire preoperatively and at least 1 year postoperatively. ADL and sports HOS subscales constitute
a validated measure of hip function for individuals with labral tears, including those undergoing arthroscopy.22 Assessment of Patient Subjective Outcome After completing the hip outcome evaluations both before and at least 1 year after surgery, patients also were asked: “How would you currently describe your hip function?” Answers included severely abnormal, abnormal, nearly normal, and normal. Statistical Methods Comparisons of patient characteristics between the labral repair and debridement groups were conducted using independent-sample t tests for continuous variables. For categorical variables, independent associations were evaluated using the Fisher exact test. Changes in ADL and sports HOS scores were assessed using paired t tests comparing the final follow-up score with baseline
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powered to detect a clinically significant difference of 7 points in the HOS score between the two groups.
Results Baseline Patient and Radiographic Characteristics All 36 patients were available for follow-up at an average of 32 months (range, 12 to 48) after unilateral hip arthroscopy. The mean duration of symptoms prior to surgical intervention was 23 months (range, 2 to 100). The labral repair group comprised 18 female patients with a mean age of 38 years (range, 20 to 59). The labral debridement group comprised 18 women with a mean age of 39 years (range, 19 to 55). Baseline patient demographics and radiographic measurements are summarized in Table 1. Baseline patient characteristics and baseline radiographic measurements did not significantly differ between the two groups. Hip Function For ADL, the mean preoperative HOS improved from 68.2 (range, 26.6 to 92.6) preoperatively to 91.2 (range, 73.3 to 100) postoperatively (P < .05) in the repair group. In the debridement group, the mean ADL HOS improved from 60.2 (range, 23.5 to 91.2) preoperatively to 80.9 (range, 42.6 to 100) postoperatively (P < .05). The repair group had a significantly greater improvement in ADL HOS (P < .05). For sports, the mean preoperative HOS in the repair group improved from 47.5 (range, 0 to 80.6) preoperatively to 88.7 (range, 28.6 to 100) postoperatively (P < .05). In the debridement group, the mean ADL HOS improved from 40.6 (range, 0 to 97.2) preoperatively to 76.3 (range, 28.6 to 100) postoperatively (P < .05). The repair group had a significantly greater improvement in sports HOS (P < .05). Fig 5. Arthroscopic views of a right hip through the anterolateral portal. (A) The pincer lesion has been exposed and is ready for debridement. The labrum is seen to be in good condition with only minor areas of unstable tissue. (B) After debridement of the pincer lesion. The labrum was not repaired but rather selectively debrided back to a stable rim. (DL, debrided labrum; FH, femoral head; L, labrum; P, pincer lesion; RF, indirect head of the rectus femoris.)
for each group. Independent-sample t tests were used to determine the differences in scores between the repair and debridement groups. For the categorical patient subjective outcome, a Fisher exact test with a 4 2 contingency table was used. Based on a large effect between labral repair and debridement in a previous study,13 we used sample size estimation to calculate that 16 patients in each group would be required to demonstrate a difference in patient subjective outcome scores of the two groups with an effect size of 0.8, with an a level of 0.05 and power of 80%.23,24 This was
Patient Subjective Outcome In the repair group, 13 patients (76%) described their preoperative hip condition as severely abnormal or Table 1. Patient Demographics and Preoperative Radiographic Findings
Demographics Number of patients Average age (yr) Gender Preop ADL HOS Preop sports HOS Radiographic findings Alpha angle Cross-over sign Ischial spine sign FAI type Pincer Combined
Labral Repair Group
Labral Debridement Group
18 38 (20e59) 18 F 68.2 (26.6e92.6) 47.5 (0e80.6)
18 39 (19e55) 18 F 60.2 (23.5e91.2) 40.6 (28.6e100)
61 (45e70) 18/18 9/18 3 15
59 (42e68) 18/18 11/18 3 15
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abnormal. After arthroscopic surgery, the patients’ reported outcomes were: 13 normal (72%), 4 near normal (22%), 1 abnormal (6%), and none severely abnormal. In the debridement group, 13 patients (76%) also described their preoperative hip condition as severely abnormal or abnormal. After arthroscopic surgery, the patients’ reported outcomes were: 5 normal (28%), 9 near normal (50%), 3 abnormal (17%), and 1 severely abnormal (6%). The labral repair group had significantly better postoperative values (P ¼ 0.046).
Discussion Arthroscopic labral debridement in selective patients without arthritis has produced good results in follow-up at 10 years.25 Conversely, several retrospective studies have reported good outcomes in patients treated arthroscopically for pincer-type FAI or combined pincerand cam-type FAI with labral refixation.6,10,11 Currently, there are limited data from comparisons of arthroscopic labral repair and debridement in similar patient groups in association with treatment for FAI. In the present prospective randomized study, the hypothesis that functional hip scores and hip subjective outcome will be superior in patients treated with labral repair compared with those who underwent selective labral debridement at shortterm follow-up was confirmed. Patients treated with labral repair had improved hip function compared with those treated with labral debridement. This agrees well with the two previous retrospective studies of labral repair versus debridement/resection. Espinosa et al. performed open surgical hip dislocation and acetabular rim trimming with labral refixation in 35 hips with FAI and retrospectively compared these results with those for 25 hips with FAI that underwent labral debridement.12 Two years after surgery, 80% of the hips in the repair group had excellent results, whereas only 28% in the labral resection group had excellent results. Furthermore, radiographic osteoarthritis was more prevalent in the labral resection group at 1 and 2 years of follow-up. It is important to note that in the labral debridement group, a complete resection of the labrum from the acetabular rim was performed, in contrast to the methods of arthroscopic labral debridement employed in the current study. For labral debridement in the current study, we performed a selective labral debridement of only the unstable portion, with preservation of as much labrum as possible. When the remaining labral tissue was diminutive after debridement, we attempted a labral “reshaping” in an attempt to maintain some functional labrum for suction seal and cartilage lubrication (Fig 5). This is analogous to performing partial meniscectomy in the knee. Historically, subtotal meniscectomies have been performed, but after observation of deterioration of the knee compartment with time, a strategy of maintaining as much meniscal tissue as
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possible to prevent increased contact pressures in the compartment was adopted. This may also be true in the hip as an ex vivo model of cartilage strain showed an increase of 2% for partial labral tear, but when total removal of the labrum was performed, cartilage strain increased by 6%.26 It is also important to note that a number of studies have examined the vascularity of the labrum in the hip and have reported the ability for the labrum to heal satisfactorily after surgical repair in an animal model.27,28 In the second comparative study, Larson et al. retrospectively evaluated a group of labral debridements that were performed before the development of labral repair techniques with a group of labral tears that were deemed repairable at the time of arthroscopic FAI surgery.13 They reported almost 90% excellent results in the repair group versus only 67% excellent results in the debridement group at a minimum of 1 year of follow-up, and a greater percentage of good to excellent results in the labral repair group at 3.5 years of followup.14 Their inclusion criteria are similar to those in the current prospective study in that a more homogeneous group of patients with pincer- or combined-type FAI were included in an attempt to attribute the improved outcomes to treatment of the acetabular side. The largest limitation of their study was the confounding factor that improvements in patient outcome could have resulted from the greater understanding of FAI (and, therefore, better patient selection) and improved arthroscopic surgical techniques that occurred during the period from the historical control to the treatment group. Nonetheless, the results of the current study confirm the findings of Larson et al. in that clinical outcome with arthroscopic labral repair was superior to that with labral debridement. In the current study, a greater percentage of patients in the labral repair group felt that their hip had returned to “normal” function than in the labral debridement group. This result suggests that the propioceptive mechanoreceptors in the labrum may be important in hip function. The acetabular labrum is vital to hip mechanics as it provides a negative seal to promote stability of the joint while also aiding lubrication of the cartilage.29 In addition, several studies have demonstrated an increase in the contact pressure on the cartilage with loss of the labrum seal.26,30 Loss of the labrum can cause increased translation of the femoral head, which may result in instability or hastened degeneration of the hip.31-33 The limitations of our study include the short-term follow-up interval and the relatively small cohort. Although the follow-up interval of 32 months in this study is short, it is comparable to the follow-up periods reported in other studies of treatment of hip labral pathology.12,13 Further follow-up is needed to confirm these preliminary results, but the results of a previous
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study of labral debridement and the radiographic progression of osteoarthritis34 suggest that the labral debridement group may worsen with time. The current series included only 18 patients in each group, and no formal a priori analysis was performed because of the lack of published data on the improvements expected after arthroscopic labral repair that were available in 2007 when the study was designed. Nevertheless, the study was not underpowered, as significant differences in two outcome measures were demonstrated. Another limitation is that neither the surgeon nor the patients were blinded to the treatment in the postoperative period, which may have influenced outcome scores and satisfaction rates. Lastly, the results of this study may not be able to be applied to the general FAI population for several reasons. First, males were excluded from this study. Second, we did not find a labrum in the repair group that could not be repaired. However, there are cases in pincer-type FAI in which the labrum is ossified or very diminutive and cannot be repaired. Lastly, in cases of coxa profunda, of which there were none in this series, it may not be possible to débride the pincer lesion without completely detaching the labrum, which would require refixation.
Conclusions Arthroscopic treatment of FAI with labral repair in women resulted in superior improvement in hip functional outcomes compared with labral debridement. In addition, a larger number of patients in the repair group subjectively rated their hip function as normal or nearly normal after surgery as compared with the labral debridement group.
References 1. Ganz R, Parvizi J, Beck M, et al. Femoroacetabular impingement: A cause of osteoarthritis of the hip. Clin Orthop Relat Res 2003;417:112-120. 2. Leunig M, Beaulé P, Ganz R. The concept of femoroacetabular impingement: Current status and future perspectives. Clin Orthop Relat Res 2009;616:616-622. 3. Audenaert E, Mahieu P, Pattyn C. Three-dimensional assessment of cam engagement in femoroacetabular impingement. Arthroscopy 2011;27:167-171. 4. Pfirrmann C, Mengiardi B, Dora C, et al. Cam and pincer femoroacetabular impingement: Characteristic MR arthrographic findings in 50 patients. Radiology 2006;240: 778-785. 5. Beck M, Kalhor M, Leunig M, et al. Hip morphology influences the pattern of damage to the acetabular cartilage: Femoroacetabular impingement as a cause of early osteoarthritis of the hip. J Bone Joint Surg Br 2005;87: 1012-1018. 6. Philippon MJ, Briggs KK, Yen Y, et al. Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: Minimum two-year follow-up. J Bone Joint Surg Br 2009;91:16-23.
7. Byrd T. Hip arthroscopy. J Am Acad Orthop Surg 2006;14: 433-444. 8. Murphy S, Tannast M, Kim Y, et al. Debridement of the adult hip for femoroacetabular impingement: Indications and preliminary clinical results. Clin Orthop Relat Res 2004;429:178-181. 9. Kamath A, Componovo R, Baldwin K, et al. Hip arthroscopy for labral tears. Review of clinical outcomes with 4.8-year mean follow-up. Am J Sports Med 2009;37: 1721-1727. 10. Kelly B, Weiland D, Schenker M, et al. Arthroscopic labral repair in the hip: Surgical technique and review of the literature. Arthroscopy 2005;21:1496-1504. 11. Philippon MJ, Weiss D, Kuppersmith D, et al. Arthroscopic labral repair and treatment of femoroacetabular impingement in professional hockey players. Am J Sports Med 2010;38:99-104. 12. Espinosa N, Rothenfluh D, Beck M, et al. Treatment of femoro-acetabular impingement: Preliminary results of labral refixation. J Bone Joint Surg Am 2006;88:925-935. 13. Larson C, Giveans M. Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement. Arthroscopy 2009;25: 369-376. 14. Larson CM, Giveans MR, Stone RM. Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement: Mean 3.5-year follow-up. Am J Sports Med 2012;40:1015-1021. 15. Johnston T, Schenker M, Briggs K, et al. Relationship between offset angle alpha and hip chondral injury in femoroacetabular impingement. Arthroscopy 2008;24:669-675. 16. Philippon MJ, Schenker M, Briggs K, et al. Femoroacetabular impingement in 45 professional athletes: Associated pathologies and return to sport following arthroscopic decompression. Knee Surg Sports Traumatol Arthrosc 2007;15:908-914. 17. Clohisy J, Carlisle J, Beaulé P, et al. A systematic approach to the plain radiographic evaluation of the young adult hip. J Bone Joint Surg Am 2008;90:47-66. 18. Tonnis D. Normal values of the hip joint for the evaluation of x-rays in children and adults. Clin Orthop Relat Res 1976;119:39-47. 19. Tönnis D, Heinecke A. Acetabular and femoral anteversion: Relationship with osteoarthritis of the hip. J Bone Joint Surg Am 1999;81:1747-1770. 20. Wiberg G. Studies on dysplastic acetabula and congenital subluxation of the hip joint with special reference to the complication of osteoarthritis. Acta Chir Scand 1939;83:28-38. 21. Robertson W, Kelly B. The safe zone for hip arthroscopy: A cadaveric assessment of central, peripheral, and lateral compartment portal placement. Arthroscopy 2008;24: 1019-1026. 22. Martin RL, Kelly BT, Philippon MJ. Evidence of validity for the Hip Outcome Score. Arthroscopy 2006;22: 1304-1311. 23. Faul F, Erdfelder E, Lang A, et al. G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods 2007;39: 175-191. 24. Faul F, Erdfelder E, Buchner A, et al. Statistical power analyses using G*Power 3.1: Tests for correlation and
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regression analyses. Behav Res Methods 2009;41:11491160. Byrd T, Jones K. Hip arthroscopy for labral pathology: Prospective analysis with 10 year follow-up. Arthroscopy 2009;25:365-368. Greaves L, Gilbart M, Yung A, et al. Effect of acetabular labral tears, repair and resection on hip cartilage strain: A 7T MR study. J Biomech 2010;43:858-863. Kelly B, Shapiro G, Digiovanni C, et al. Vascularity of the hip labrum: a cadaveric investigation. Arthroscopy 2005;21:3-11. Philippon MJ, Arnoczky S, Torrie A. Arthroscopic repair of the acetabular labrum: A histologic assessment of healing in an ovine model. Arthroscopy 2007;23:376-380. Ferguson S, Bryant J, Ganz R, et al. The influence of the acetabular labrum on hip joint cartilage consolidation: A poroelastic finite element model. Clin Biomech 2000;15: 463-468.
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30. Ferguson S, Bryant J, Ganz R, et al. An in vitro investigation of the acetabular labral seal in hip joint mechanics. J Biomech 2003;36:171-178. 31. Crawford M, Dy C, Alexander J, et al. The 2007 Frank Stinchfield Award. The biomechanics of the hip labrum and the stability of the hip joint. Clin Orthop Relat Res 2007;465:16-22. 32. Dy C, Thompson M, Crawford M, et al. Tensile strain in the anterior part of the acetabular labrum during provocative maneuvering of the normal hip. J Bone Joint Surg Am 2008;90:1464-1472. 33. Safran M. The acetabular labrum: anatomic and functional characteristics and rationale for surgical intervention. J Am Acad Othop Surg 2010;18:338-345. 34. Peters C, Erickson J. Treatment of femoro-acetabular impingement with surgical dislocation and débridement in young adults. J Bone Joint Surg Am 2006;88:1735-1741.
Purpose: The purpose of this prospective randomized study was to compare the outcomes of arthroscopic labral repair and selective labral debridement in female patients undergoing arthroscopy for the treatment of pincer-type or combined pincer- and cam-type femoroacetabular impingement. Methods: Between June 2007 and June 2009, 36 female patients undergoing arthroscopic hip treatment for pincer- or combined-type femoroacetabular impingement were randomized to 2 treatment groups at the time of surgery: labral repair or labral debridement. The repair group comprised 18 patients with a mean age of 38; the debridement group comprised 18 patients with a mean age of 39. All patients underwent the same rehabilitation protocol postoperatively. At a minimum of 1 year, all patients were assessed using a validated Hip Outcome Score (HOS) to determine hip function, and also completed a simple subjective outcome measure. Results: All 36 patients were available for follow-up at an average time of 32 months (range, 12 to 48). In both groups, HOSs for activities of daily living (ADL) and sports improved significantly from before surgery to the final follow-up (P < .05). The postoperative ADL HOS was significantly better in the repair group (91.2; range, 73 to 100) compared with the debridement group (80.9; range, 42.6 to 100; P < .05). Similarly, the postoperative sports HOS was significantly greater in the repair group (88.7; range, 28.6 to 100) than in the debridement group (76.3; range, 28.6 to 100; P < .05). Additionally, patient subjective outcome was significantly better in the labral repair group (P ¼ .046). Conclusions: Arthroscopic treatment of femoroacetabular impingement with labral repair in female patients resulted in superior improvement in hip functional outcomes compared with labral debridement. In addition, a greater number of patients in the repair group subjectively rated their hip function as normal or nearly normal after surgery compared with the labral debridement group. Level of Evidence: Level I, prospective randomized study.
F
emoroacetabular impingement (FAI) is a clinical syndrome associated with abnormalities of the shape and orientation of the hip causing conflict between the femur and acetabulum that can lead to pain, dysfunction, and early osteoarthritis.1,2 This aberrant, repetitive impact is the result of a mis-shapen
From the Department of Orthopedic Surgery (A.J.K.), Mayo Clinic, Rochester, Minnesota; Drisko, Fee & Parkins Orthopedics (M.T.), Independence, Missouri; Oklahoma Sports and Orthopedics Institute (Z.K.), Norman, Oklahoma; and Department of Orthopedic Surgery (J.S., S.H.C.), Hospital for Special Surgery, New York, New York, U.S.A. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received October 24, 2011; accepted July 20, 2012. Address correspondence to Aaron J. Krych, M.D., Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, U.S.A. E-mail: [email protected] Ó 2013 by the Arthroscopy Association of North America 0749-8063/11694/$36.00 http://dx.doi.org/10.1016/j.arthro.2012.07.011
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femoral head or neck (cam impingement), a malrotated or overly deep acetabulum (pincer impingement), or a combination of the two.3,4 Cam-type FAI is characterized by chondrolabral delamination on the acetabulum.1,2 Pincer impingement often results in repetitive damage to the labrum, sometimes causing a progressively diminutive and ossified labrum, with damage to the femoral headeneck junction.5,6 There are several reports of successful short-term outcomes after labral debridement in nonarthritic hips,7,8 as well as labral refixation/repair.6,9-11 Nevertheless, few studies have compared the effects of labral repair and labral debridement on functional outcome after hip surgery to treat FAI. In 2006, Espinosa et al. retrospectively compared open labral resection with labral refixation in association with treatment of FAI and reported improved patient outcomes and less osteoarthritis in patients having labral refixation.12 Similarly, in 2009, Larson et al. retrospectively examined their results of arthroscopic labral debridement versus labral repair
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 29, No 1 (January), 2013: pp 46-53
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Enrollment
Assessed for eligibility (n = 41) Excluded (n =5) Refused to participate (n =5)
Allocated to labral repair (n =18)
Follow up
Allocation
Randomized (n =36)
12-month follow-up (n = 18)
Analysis
during the management of FAI and reported superior outcomes in the group treated with labral repair13; they recently published the midterm results for these patients.14 However, both these studies were retrospective and compared a labral repair group with a historical control labral excision group. The main limitation of a historical control group is that significant improvements have occurred in the understanding of and technical advances in treating FAI, introducing confounding variables that could have resulted in the greater improvement in the patients who underwent labral repair. To our knowledge, there are no prospective, randomized studies or even comparative studies during the same period assessing labral debridement versus repair, in either open or arthroscopic treatment of FAI. Therefore, we designed a prospective randomized study of labral repair versus selective labral debridement in association with arthroscopic treatment of either pincer-type or combined pincer- and cam-type FAI. In this study, males were excluded as they tend to have higher alpha angles, indicating more of a camtype FAI,11,15,16 and it would be difficult to assess postoperative improvement attributed to treatment of the labrum. The purpose of this study was to determine if (1) functional outcome was superior in patients treated with labral repair compared with those who underwent selective labral debridement as measured with the validated Hip Outcome Score (HOS), and (2) subjective patient outcome was better in patients treated with labral repair than in those treated with selective labral debridement. We hypothesize that even at short-term follow-up, labral repair would lead to improved hip function scores and patient subjective outcomes when compared with labral debridement in the context of arthroscopic treatment of FAI.
Analyzed (n =18)
Allocated to selective labral debridement (n =18)
12-month follow-up (n = 18)
Analyzed (n =18)
Fig 1. CONSORT diagram showing the flow of participants through each stage of this randomized trial.
Design This randomized clinical trial was conducted from June 2007 through June 2009. Forty-one consecutive female patients with pincer- or combined-type FAI were identified as meeting the criteria, and 36 of those patients agreed to enroll in this trial (Fig 1). All patients gave written consent to participate in the study, and the study was approved by our institutional review board. Data were collected as part of our institution’s prospective hip registry.
pincer-type FAI. Radiographic evidence consisted of the presence of relative acetabular retroversion on a true anteroposterior plain pelvic radiograph, as indicated by a cross-over sign and prominent ischial spine sign; coxa profunda; acetabular protrusion; or a pincer divot at the femoral neck headeneck junction.17 In addition, the presence of labral tear/pathology was required on magnetic resonance imaging (MRI). The presence of a cam lesion was also noted, but did not exclude patients from the study as long as pincer-type FAI coexisted. Cam impingement was defined as an alpha angle greater than 45 on an oblique radiograph. 17 In most cases, an intra-articular injection of lidocaine was used to confirm the diagnosis. Exclusion criteria included pure cam-type FAI, as management of labral lesions in this setting does not necessarily require rim trimming.3,4 Males were excluded as they tend to have higher alpha angles, indicating more of a cam-type FAI,11,15,16 and it would be difficult to assess postoperative improvement attributed to treatment of the labrum. Other exclusion criteria included previous hip surgery, Tonnis grade 2 osteoarthritis,18,19 hip dysplasia based on radiographic evidence of a Wiberg lateral center edge angle less than 25 ,17,20 and patient age less than 18.
Inclusion Criteria Patients were eligible for the study if they were female, greater than 17 years of age, and diagnosed with either pincer-type or combined-type (coexistent pincerand cam-type) FAI. The diagnosis of pincer-type FAI was made on the basis of history, positive impingement signs on examination, and radiographic evidence of
Randomization and Blinding After enrolling, patients reported to the preoperative area on the day of surgery. They were then transferred to the operating room and, prior to placement of hip traction, were randomized to either labral repair or debridement. Randomization was carried out by opening one of 36 sealed, opaque envelopes assigning
Methods
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patients to receive either labral repair or debridement. The surgeon and patient were not blinded to treatment after the procedure. Surgical Procedure All 36 arthroscopic hip surgeries were performed by the senior author, an experienced hip arthroscopist (S.H.C.). Patients were positioned on a modified traction table and subjected to 25 to 50 pounds of traction to distract the operative hip. Three standard arthroscopy portals were used during the procedure: the anterolateral portal, the midanterior portal, and the distal anterolateral accessory portal. We use the landmarks established for safe portals, as described by Robertson and Kelly.21 Diagnostic arthroscopy was performed first to evaluate the labrum and articular cartilage. A capsulotomy was performed between the anterolateral and midanterior portals to achieve increased maneuverability within the hip joint. In the labral repair group, the soft tissue and capsule were removed using a cautery device to expose the pincer lesion (Fig 2). The labrum was left attached to the transitional fibers of the acetabular cartilage. Under fluoroscopic guidance, the portion of the anterior rim that was causing overcoverage was removed using a 5.5-mm burr (Fig 3). The labrum was then rolled back to the bone and repaired to the rim of the acetabulum using multiple suture anchors (Fig 4). For labral repair, a cannula was placed through a working midanterior (for working more medially) or anterolateral (for working more laterally) portal. A single-loaded PEEK suture anchor was then placed through the distal anterolateral accessory portal to create a more cephalad angle to avoid penetration of the acetabulum. A sharp tissue penetrator was then used through the cannula in either the midanterior or anterolateral portal to pass the nonabsorbable suture from the suture anchor using an intrasubstance stitch through the labrum. This was then tied using an arthroscopic sliding knot, and the ends were trimmed. An average of 3.1 suture anchors were used per repair (range, 2-4). In the labral debridement group, selective labral debridement was performed with preservation of as much stable labrum as possible to retain a functional seal between the labrum and the femoral head (Fig 5). The pincer lesion was then visualized without separation of the labrum from the acetabulum, and under fluoroscopic guidance, the portion of the anterior rim that was causing overcoverage was removed using a 5.5-mm burr. In all cases, the remaining labrum was stable to probing and no unstable labral tissue was left behind. Next, the traction was released and the hip was flexed approximately 40 . A longitudinal cut was made in the capsule along the femoral neck to evaluate the headeneck junction for the presence of a cam lesion. If a cam lesion was identified, a 5.5-mm burr was used to
Fig 2. Arthroscopic views of a left hip through the midanterior portal. (A) The pincer lesion is visualized superior to the labrum, which has been exposed by careful delineation of the labrum using an arthroscopic elevator and cautery device. (B) After resection of the pincer lesion and subanterior inferior iliac spine area. (A, acetabulum; AIIS, anterior inferior iliac spine; DP, debrided pincer; L, labrum; P, pincer lesion.)
resect the lesion. Fluoroscopy was used to guide the resection of the femoral neck. After removal of the cam lesion, the capsule was repaired using interrupted permanent suture. The portals were closed and a sterile dressing was applied. In both groups, 3 patients underwent only rim reduction for pincer-type impingement, whereas 15 patients underwent additional femoral neck osteochondroplasty for combined cam- and pincer-type impingement. Postoperative Care All patients were managed with the same postoperative pain regimen and rehabilitation protocol.
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Fig 4. Arthroscopic views of a right hip through the anterolateral portal. (A) The pincer lesion has been debrided and a suture anchor is being inserted through the midanterior portal. (B) The labrum has been repaired to the superior rim of the acetabulum with a vertical mattress intrasubstance suture configuration. Fig 3. Intraoperative fluoroscopic images of a left hip. (A) Anteroposterior view of the hip showing the lateralized anterior wall of the acetabulum (outlined in yellow) relative to the more medial posterior wall (outlined in blue). This radiographic finding is consistent with the pincer lesion seen intraoperatively. (B) Same AP view of the hip after resection of the pincer lesion, correcting the anterior overcoverage.
Postoperatively, patients were placed on crutches for 2 weeks with foot-flat partial weight bearing. Passive motion was started immediately. Patients were restricted from passive hip rotation for 4 weeks. A specific hip rehabilitation protocol was initiated between postoperative days 7 and 10. Assessment of Hip Function All patients completed a self-administered HOS questionnaire preoperatively and at least 1 year postoperatively. ADL and sports HOS subscales constitute
a validated measure of hip function for individuals with labral tears, including those undergoing arthroscopy.22 Assessment of Patient Subjective Outcome After completing the hip outcome evaluations both before and at least 1 year after surgery, patients also were asked: “How would you currently describe your hip function?” Answers included severely abnormal, abnormal, nearly normal, and normal. Statistical Methods Comparisons of patient characteristics between the labral repair and debridement groups were conducted using independent-sample t tests for continuous variables. For categorical variables, independent associations were evaluated using the Fisher exact test. Changes in ADL and sports HOS scores were assessed using paired t tests comparing the final follow-up score with baseline
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powered to detect a clinically significant difference of 7 points in the HOS score between the two groups.
Results Baseline Patient and Radiographic Characteristics All 36 patients were available for follow-up at an average of 32 months (range, 12 to 48) after unilateral hip arthroscopy. The mean duration of symptoms prior to surgical intervention was 23 months (range, 2 to 100). The labral repair group comprised 18 female patients with a mean age of 38 years (range, 20 to 59). The labral debridement group comprised 18 women with a mean age of 39 years (range, 19 to 55). Baseline patient demographics and radiographic measurements are summarized in Table 1. Baseline patient characteristics and baseline radiographic measurements did not significantly differ between the two groups. Hip Function For ADL, the mean preoperative HOS improved from 68.2 (range, 26.6 to 92.6) preoperatively to 91.2 (range, 73.3 to 100) postoperatively (P < .05) in the repair group. In the debridement group, the mean ADL HOS improved from 60.2 (range, 23.5 to 91.2) preoperatively to 80.9 (range, 42.6 to 100) postoperatively (P < .05). The repair group had a significantly greater improvement in ADL HOS (P < .05). For sports, the mean preoperative HOS in the repair group improved from 47.5 (range, 0 to 80.6) preoperatively to 88.7 (range, 28.6 to 100) postoperatively (P < .05). In the debridement group, the mean ADL HOS improved from 40.6 (range, 0 to 97.2) preoperatively to 76.3 (range, 28.6 to 100) postoperatively (P < .05). The repair group had a significantly greater improvement in sports HOS (P < .05). Fig 5. Arthroscopic views of a right hip through the anterolateral portal. (A) The pincer lesion has been exposed and is ready for debridement. The labrum is seen to be in good condition with only minor areas of unstable tissue. (B) After debridement of the pincer lesion. The labrum was not repaired but rather selectively debrided back to a stable rim. (DL, debrided labrum; FH, femoral head; L, labrum; P, pincer lesion; RF, indirect head of the rectus femoris.)
for each group. Independent-sample t tests were used to determine the differences in scores between the repair and debridement groups. For the categorical patient subjective outcome, a Fisher exact test with a 4 2 contingency table was used. Based on a large effect between labral repair and debridement in a previous study,13 we used sample size estimation to calculate that 16 patients in each group would be required to demonstrate a difference in patient subjective outcome scores of the two groups with an effect size of 0.8, with an a level of 0.05 and power of 80%.23,24 This was
Patient Subjective Outcome In the repair group, 13 patients (76%) described their preoperative hip condition as severely abnormal or Table 1. Patient Demographics and Preoperative Radiographic Findings
Demographics Number of patients Average age (yr) Gender Preop ADL HOS Preop sports HOS Radiographic findings Alpha angle Cross-over sign Ischial spine sign FAI type Pincer Combined
Labral Repair Group
Labral Debridement Group
18 38 (20e59) 18 F 68.2 (26.6e92.6) 47.5 (0e80.6)
18 39 (19e55) 18 F 60.2 (23.5e91.2) 40.6 (28.6e100)
61 (45e70) 18/18 9/18 3 15
59 (42e68) 18/18 11/18 3 15
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abnormal. After arthroscopic surgery, the patients’ reported outcomes were: 13 normal (72%), 4 near normal (22%), 1 abnormal (6%), and none severely abnormal. In the debridement group, 13 patients (76%) also described their preoperative hip condition as severely abnormal or abnormal. After arthroscopic surgery, the patients’ reported outcomes were: 5 normal (28%), 9 near normal (50%), 3 abnormal (17%), and 1 severely abnormal (6%). The labral repair group had significantly better postoperative values (P ¼ 0.046).
Discussion Arthroscopic labral debridement in selective patients without arthritis has produced good results in follow-up at 10 years.25 Conversely, several retrospective studies have reported good outcomes in patients treated arthroscopically for pincer-type FAI or combined pincerand cam-type FAI with labral refixation.6,10,11 Currently, there are limited data from comparisons of arthroscopic labral repair and debridement in similar patient groups in association with treatment for FAI. In the present prospective randomized study, the hypothesis that functional hip scores and hip subjective outcome will be superior in patients treated with labral repair compared with those who underwent selective labral debridement at shortterm follow-up was confirmed. Patients treated with labral repair had improved hip function compared with those treated with labral debridement. This agrees well with the two previous retrospective studies of labral repair versus debridement/resection. Espinosa et al. performed open surgical hip dislocation and acetabular rim trimming with labral refixation in 35 hips with FAI and retrospectively compared these results with those for 25 hips with FAI that underwent labral debridement.12 Two years after surgery, 80% of the hips in the repair group had excellent results, whereas only 28% in the labral resection group had excellent results. Furthermore, radiographic osteoarthritis was more prevalent in the labral resection group at 1 and 2 years of follow-up. It is important to note that in the labral debridement group, a complete resection of the labrum from the acetabular rim was performed, in contrast to the methods of arthroscopic labral debridement employed in the current study. For labral debridement in the current study, we performed a selective labral debridement of only the unstable portion, with preservation of as much labrum as possible. When the remaining labral tissue was diminutive after debridement, we attempted a labral “reshaping” in an attempt to maintain some functional labrum for suction seal and cartilage lubrication (Fig 5). This is analogous to performing partial meniscectomy in the knee. Historically, subtotal meniscectomies have been performed, but after observation of deterioration of the knee compartment with time, a strategy of maintaining as much meniscal tissue as
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possible to prevent increased contact pressures in the compartment was adopted. This may also be true in the hip as an ex vivo model of cartilage strain showed an increase of 2% for partial labral tear, but when total removal of the labrum was performed, cartilage strain increased by 6%.26 It is also important to note that a number of studies have examined the vascularity of the labrum in the hip and have reported the ability for the labrum to heal satisfactorily after surgical repair in an animal model.27,28 In the second comparative study, Larson et al. retrospectively evaluated a group of labral debridements that were performed before the development of labral repair techniques with a group of labral tears that were deemed repairable at the time of arthroscopic FAI surgery.13 They reported almost 90% excellent results in the repair group versus only 67% excellent results in the debridement group at a minimum of 1 year of follow-up, and a greater percentage of good to excellent results in the labral repair group at 3.5 years of followup.14 Their inclusion criteria are similar to those in the current prospective study in that a more homogeneous group of patients with pincer- or combined-type FAI were included in an attempt to attribute the improved outcomes to treatment of the acetabular side. The largest limitation of their study was the confounding factor that improvements in patient outcome could have resulted from the greater understanding of FAI (and, therefore, better patient selection) and improved arthroscopic surgical techniques that occurred during the period from the historical control to the treatment group. Nonetheless, the results of the current study confirm the findings of Larson et al. in that clinical outcome with arthroscopic labral repair was superior to that with labral debridement. In the current study, a greater percentage of patients in the labral repair group felt that their hip had returned to “normal” function than in the labral debridement group. This result suggests that the propioceptive mechanoreceptors in the labrum may be important in hip function. The acetabular labrum is vital to hip mechanics as it provides a negative seal to promote stability of the joint while also aiding lubrication of the cartilage.29 In addition, several studies have demonstrated an increase in the contact pressure on the cartilage with loss of the labrum seal.26,30 Loss of the labrum can cause increased translation of the femoral head, which may result in instability or hastened degeneration of the hip.31-33 The limitations of our study include the short-term follow-up interval and the relatively small cohort. Although the follow-up interval of 32 months in this study is short, it is comparable to the follow-up periods reported in other studies of treatment of hip labral pathology.12,13 Further follow-up is needed to confirm these preliminary results, but the results of a previous
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study of labral debridement and the radiographic progression of osteoarthritis34 suggest that the labral debridement group may worsen with time. The current series included only 18 patients in each group, and no formal a priori analysis was performed because of the lack of published data on the improvements expected after arthroscopic labral repair that were available in 2007 when the study was designed. Nevertheless, the study was not underpowered, as significant differences in two outcome measures were demonstrated. Another limitation is that neither the surgeon nor the patients were blinded to the treatment in the postoperative period, which may have influenced outcome scores and satisfaction rates. Lastly, the results of this study may not be able to be applied to the general FAI population for several reasons. First, males were excluded from this study. Second, we did not find a labrum in the repair group that could not be repaired. However, there are cases in pincer-type FAI in which the labrum is ossified or very diminutive and cannot be repaired. Lastly, in cases of coxa profunda, of which there were none in this series, it may not be possible to débride the pincer lesion without completely detaching the labrum, which would require refixation.
Conclusions Arthroscopic treatment of FAI with labral repair in women resulted in superior improvement in hip functional outcomes compared with labral debridement. In addition, a larger number of patients in the repair group subjectively rated their hip function as normal or nearly normal after surgery as compared with the labral debridement group.
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30. Ferguson S, Bryant J, Ganz R, et al. An in vitro investigation of the acetabular labral seal in hip joint mechanics. J Biomech 2003;36:171-178. 31. Crawford M, Dy C, Alexander J, et al. The 2007 Frank Stinchfield Award. The biomechanics of the hip labrum and the stability of the hip joint. Clin Orthop Relat Res 2007;465:16-22. 32. Dy C, Thompson M, Crawford M, et al. Tensile strain in the anterior part of the acetabular labrum during provocative maneuvering of the normal hip. J Bone Joint Surg Am 2008;90:1464-1472. 33. Safran M. The acetabular labrum: anatomic and functional characteristics and rationale for surgical intervention. J Am Acad Othop Surg 2010;18:338-345. 34. Peters C, Erickson J. Treatment of femoro-acetabular impingement with surgical dislocation and débridement in young adults. J Bone Joint Surg Am 2006;88:1735-1741.