1 Management of the Acetabular Labrum a, b Andrew B. Wolff, MD *, Jamie Grossman, MD KEYWORDS Acetabular labrum Labral reconstruction Labral repair Labral debridement Hip preservation KEY POINTS The acetabular labrum is a biomechanically important structure that stabilizes the hip and protects the articular cartilage. The labrum has free nerve fibers and can be a pain generator. Painless restoration of normal hip biomechanics should be the goal of clinical correction of labral dysfunction through labral debridement, labral repair, or labral reconstruction. Labral debridement, repair, and reconstruction can be viable treatment options in the correct clinical setting. INTRODUCTION A normal-functioning acetabular labrum can be an important component of a stable, long-lasting, and well-functioning hip joint. A compromised labrum can be the source of significant disability and pain. Painless restoration of normal hip biomechanics should be the goal of arthroscopic treatment of labral dysfunction through labral debridement, repair, or reconstruction. Biomechanically, multiple in vivo studies have demonstrated the function of the labrum. Ferguson and colleagues1,2 demonstrated that the labrum distributes joint forces, stabilizes the hip, and acts as a seal to promote lubrication and preserve carti- lage, and with its removal, the articular cartilage layers compress 40% more quickly. Other investigators have shown that the labrum contributes to hip stability by increasing acetabular surface area, volume, and stiffness, and by creating a negative intra-articular pressure that results in resistance to displacement.3 The hip fluid seal provided by the labrum maintains pressure within the joint to protect the cartilage Disclosure Statement: Dr A.B. Wolff is a Consultant for Stryker. There is no commercial bias in the material of this article. a Washington Orthopaedics and Sports Medicine, 2021 K Street Northwest, Suite 516, Washington, DC 20006, USA; b Department of Orthopaedic Surgery, Lenox Hill Hospital, 210 East 64th Street, New York, NY 10065, USA * Corresponding author. andrewwolffmd.com 2 Wolff & Grossman matrix from as much as 90% of the load and decreases friction between the femoral 4,5 head and acetabulum. To restore these labral functions, 3 surgical options exist: debridement, repair, and reconstruction. Historically, debridement was the only option. In 2006, Espinosa and 6 colleagues demonstrated superior results among patients in whom the labrum was refixed to the acetabular rim after open surgical dislocation for correction of femoroa- cetabular impingement (FAI). In this study, only 28% of the resection group had excel- lent results, whereas 80% of the labral reattachment group had excellent results. This work, in concert with improved arthroscopic instrumentation and techniques, led to an attempt to preserve the labrum and restore its anatomy and function to approximate 7 that of a “normal” hip. In 2009, Larson reported superior outcomes among his pa- tients who underwent arthroscopic refixation of the labrum versus debridement. Of the patients in the refixation group, 89% had good to excellent results compared with only 66% of patients who underwent debridement. These results have continued 8 to be superior at midterm follow-up (92% vs 68%). Several studies have supported these findings and demonstrated significantly better clinical outcomes with repair 8,9 when compared with resection or debridement. Understanding that patients generally fare better with a repair and that the hip has improved mechanical properties with a functioning labrum led to the development of labral reconstruction techniques as an option for patients with labral tissue that was missing or damaged beyond repair. Although labral reconstruction had been reported 10 11 in a case series of 5 surgical dislocations, Philippon and colleagues were the first to describe their promising early results in a large series with arthroscopic labral 12 reconstruction in patients without osteoarthritis. More recently, White and col- 13 leagues showed excellent 2-year results in a series of 152 consecutive hips that 14 underwent arthroscopic labral reconstruction. Domb and colleagues found signifi- cantly better results in patients undergoing arthroscopic labral reconstruction compared to those undergoing labral resection for labra damaged beyond repair as measured by Non-arthritic Hip Score (NAHS) and hip outcome score (HOS)-activities 15 of daily living (ADL) scores. Taking it a step farther, Matsuda and Burchette compared their results with arthroscopic labral reconstruction with refixation in a matched cohort study and found that NAHS scores were significantly higher in the 16 reconstruction group at 2-year follow-up. Similarly, Wolff and colleagues recently re- ported on 1-year follow-up in a consecutive series of 107 patients, that the 46 who un- derwent circumferential labral reconstruction had an improvement across all outcome measures statistically indistinguishable from the patients who underwent labral repair despite being significantly older with more severe labral damage (or deficiency). Furthermore, in the reconstruction group, 35% were revisions compared with 3% of the repair group16 (Table 1). DEBRIDEMENT, REPAIR, RECONSTRUCTION: DOES IT MATTER? Although there is a substantial and growing body of evidence that suggests both labral repair and reconstruction (probably more so than debridement) can help patients with hip pain, these treatments are not often performed in isolation. Increasing numbers of labral repairs among reporting investigators have historically paralleled not only ad- vances in our understanding and ability to treat other conditions of the hip often per- formed concomitantly (ie, correction of FAI), but also a refinement of techniques, of patient selection, and a more thorough understanding of rehabilitation. Thus, some portion of the historically inferior results with labral debridement is likely attributable to the learning curves of both individual hip surgeons and the community of hip Table 1 Published open and arthroscopic labral reconstruction outcomes Open vs Arthroscopic/ Preoperative Study Graft n Sex Age Follow-up Convert to THA Outcome Postoperative Outcome Sierra and Open/ligamentum teres 5 3 M, 2 F 33 (19–50) y 10 (5–20) mo 1 (20%) 3 “severe pain” 3 “no pain” Trousdale capitis autograft 2 “moderately 1 “moderate pain” severe pain” 1 “same pain as UCLA: 5 (2–6) preoperatively” UCLA: 8 (6–10) Walker et al Open/ligamentum teres 20 5 M, 14 F 29 (16–50) y 26 (12–56) mo 3 (15%) Not reported UCLA: 8.5 (5–10) capitis autograft or fascia lata autograft White et al Arthroscopic/iliotibial 152 64 M, 78 F 39 (16–58) y 28 (24–39) mo 13 (10%) MHHS: 54 MHHS: 88 band allograft LEFS: 41 LEFS: 68 VAS rest: 5 VAS rest: 2 Management of the Acetabular Labrum VAS ADLs: 6 VAS ADLs: 2 VAS sport: 8 VAS sport: 3 Satisfaction: 9/10 Philippon et al Arthroscopic/iliotibial 47 32 M, 15 F 37 (18–55) y 18 (12–32) mo 4 (9%) MHHS: 62 MHHS: 85 band autograft Satisfaction: 8/10 Geyer et al Arthroscopic/iliotibial 76 42 M, 33 F 39 (18–64) y 49 (36–70) mo 18 (24%) 1 1 (1%) MHHS: 59 MHHS: 83 band autograft resurface HOS-ADL: 69 HOS-ADL: 81 HOS-Sport: 41 HOS-Sport: 67 SF-12 physical: 42 SF-12 physical: 50 SF-12 mental: 55 SF-12 mental: 53 Satisfaction: 8/10 (continued on next page) 3 4 Wolff & Grossman Table 1 (continued) Open vs Arthroscopic/ Preoperative Study Graft n Sex Age Follow-up Convert to THA Outcome Postoperative Outcome Boykin et al Arthroscopic/iliotibial 21 19 M, 0 F 28 (19–41) y 41 (20–74) mo 2 (10%) MHHS: 67 MHHS: 84 band autograft HOS-ADL: 77 HOS-ADL: 85 HOS-Sport: 56 HOS-Sport: 77 SF-12 physical: 44 SF-12 physical: 51 SF-12 mental: 49 SF-12 mental: 54 Satisfaction: 8/10 Returned to play: 18 (86%) Matsuda and Arthroscopic/gracilis 8 7 M, 1 F 35 (18–58) y 30 (24–37) mo 0 (0%) NAHS: 42 NAHS: 92 Burchette autograft Satisfaction: 7 “high,”1 “moderate” Domb et al Arthroscopic/gracilis 11 7 M, 4 F 33 (18–45) y 26 (24–32) mo 0 (0%) NAHS: 53 NAHS: 78 tendon autograft HOS-ADL: 59 HOS-ADL: 80 HOS-Sport: 39 HOS-Sport: 60 MHHS: 55 MHHS: 82 VAS: 7 VAS: 3 Satisfaction: 8/10 Abbreviations: ADLs, activities of daily living; HOS-ADL, hip outcome score-activities of daily living; HOS-Sport, hip outcome score-sports-specific subscale; NAHS, nonarthritic hip score; MHHS, modified Harris hip score; SF-12 mental, short form-12 mental component; SF-12 physical, short form-12 physical component; VAS, visual analog scale for pain. Data are expressed as count (%) or mean (range). From White BJ, Herzog MM. Labral reconstruction: when to perform and how. Front Surg 2015;2:27. Management of the Acetabular Labrum 5 surgeons at large. Furthermore, as evidenced by most patients doing well with labral 17 debridement and from studies such as that of Register and colleagues finding labral tears in 69% of asymptomatic individuals on MRI, we know that there are many people who can tolerate an imperfect labrum. DEBRIDEMENT, REPAIR, RECONSTRUCTION: IT PROBABLY MATTERS Although there are those who can tolerate an imperfect labrum, there are clearly those who cannot. Aside from the clinical data that show fairly convincingly the superiority of labral restoration to debridement, there are in vivo studies that offer some rationale as why this may be. The Labrum is a Pain Generator Haversath and colleagues18 reported that there is pain-associated free nerve expres- sion within the labrum, predominately at its base with the highest concentration anterosuperiorly. The Labrum is a Fibrocartilaginous Structure Seldes and colleagues19 described the histology of the labrum as a cartilaginous structure similar to a meniscus. The knee literature shows good results with repair of certain types of acute meniscal tears,20 but notably bad results with repair of com- plex, degenerative meniscal tears.21,22 Although not completely analogous structures, it would be difficult to imagine that a complex degenerative tear of a fibrocartilaginous structure in the hip would heal at a markedly higher rate by placing sutures around it.