Chondrolabral Junction Breakdown Predicts Progression to THA After Hip Arthroscopy for Labral Tears
Key findings
- This retrospective study (minimum follow-up of eight years) analyzed outcomes of 174 adults who underwent hip arthroscopy for labral tears secondary to femoroacetabular impingement
- The overall 10-year survivorship rate (no progression to total hip arthroplasty) was 82%, but the rate was only 44% in patients exhibiting severe chondrolabral junction (CLJ) breakdown intraoperatively vs. 98% in those with mild CLJ breakdown (P<0.001)
- Older age, worse Tönnis grade and more severe CLJ breakdown were independent predictors of total hip arthroplasty
- Until emerging MRI techniques allow improved preoperative CLJ grading, orthopedic surgeons should consider potential associations of patient age, body mass index, and radiographic findings with severe CLJ damage
Previous preclinical research conducted by Scott D. Martin, MD, director of the Joint Preservation Service in the Department of Orthopaedic Surgery at Massachusetts General Hospital, and his team has revealed unique histologic features of the chondrolabral junction using a caprine model; however, the clinical relevance of this transition zone has not yet been investigated.
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Moreover, although accumulating evidence suggests arthroscopic treatment of femoroacetabular impingement (FAI) and symptomatic labral tears improves both symptoms and function in the short- and mid-term, long-term outcomes remain limited.
To gain insight into the chondrolabral junction and other patient characteristics that predict durable long-term outcomes, researchers at Mass General reviewed data on 174 adults who underwent hip arthroscopy by a single senior surgeon to treat symptomatic labral tears secondary to FAI between March 2002 and June 2013.
Michael C. Dean, BA, of the Department of Orthopaedic Surgery, Dr. Martin, and colleagues report in The American Journal of Sports Medicine that most patients achieved favorable minimum eight-year outcomes. However, worse chondrolabral junction (CLJ) breakdown, higher Tönnis grade, and older age were independent predictors of progression to total hip arthroplasty (THA).
Patient Characteristics
The cohort was 51% female with a mean age of 38 and mean body mass index of 26 kg/m2. 78% of patients had Tönnis grade ≤1 preoperatively.
Intraoperatively, 30% of patients exhibited severe breakdown of the CLJ (Beck classification ≥3) and the others exhibited mild breakdown. 76% of patients underwent acetabuloplasty, femoroplasty, or both, and in that era, similar proportions of patients underwent labral repair (48%) or debridement (52%).
Conversion to THA
Over the mean follow-up period of 11 years, 19.5% of patients required THA at a mean interval of 4.7 years after hip arthroscopy. The overall 10-year survivorship rate (no conversion to THA) was 82%.
Survivorship at 10 years was only 44% in patients exhibiting severe CLJ breakdown versus 98% in those with mild CLJ breakdown (P<0.001).
Predictors of Conversion to THA
In unadjusted analyses, variables significantly associated with progression to THA were older age, higher BMI, worse Tönnis grade, larger Tönnis and alpha angles, and smaller mean radiographic joint space. Intraoperative factors were the breakdown of the CLJ, worse cartilage damage on the femoral head or acetabulum, larger or more severe labral tearing, and labral debridement.
Predictors of failure that remained in a weighted Cox regression analysis were:
- Worse CLJ breakdown (weighted HR per 1-unit increase, 6.41; P<0.001)
- Older age (weighted HR per 1-year increase, 1.09; P<0.001)
- Higher Tönnis grade (weighted HR per 1-unit increase, 4.59; P<0.001)
Secondary Outcomes
Two patients (1%) underwent revision hip arthroscopy without conversion to THA.
At the final follow-up, patient-reported outcome measures were similar between patients who exhibited severe versus mild CLJ breakdown. These included the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, International Hip Outcome Tool–33, modified Harris Hip Score, Non-Arthritic Hip Score, and questions about patient satisfaction.
Guidance for Surgeons
The CLJ acts as a seamless transition zone between the fibrocartilaginous labrum and hyaline articular cartilage. The lower rate of durable outcomes among patients with advanced CLJ breakdown substantiates the limited healing capacity of this zone and emphasizes the importance of intervening before severe damage occurs.
Emerging MRI modalities (e.g., 3.0-T delayed gadolinium-enhanced MRI of cartilage; T1r, T2, and T2* mapping) may enhance preoperative grading of the CLJ. Until these techniques become routinely available, orthopedic surgeons should consider the associations established in this study between CLJ breakdown and observable preoperative factors (e.g., radiographic parameters, age, and BMI).
This study doesn't imply hip arthroscopy should be reserved for younger patients with FAI. Rather, surgeons should carefully consider age and other patient characteristics during shared decision-making.
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