Mechanical stretching induces calcification and cartilage matrix metabolism, causing degeneration of the acetabular labrum

Purpose: The acetabular labrum plays an important role in joint lubrication, and damage to this structure leads to osteoarthritis. This study aimed to histologically classify the degree of degeneration of the acetabular labrum and to investigate the changes in gene expression induced by mechanical stretching. Methods: We obtained acetabular labrum cells from patients with hip osteoarthritis during total hip arthroplasty ( n = 25). The labrum was stained with safranin O, and images were histologically evaluated using a new parameter, the red/blue (R/B) value. The samples were divided into the degenerated group (D group: n = 18) and the healthy group (H group: n = 7) in accordance with the Kellgren-Lawrence (KL) grade. The cultured acetabular labral cells were subjected to loaded uniaxial cyclic tensile strain (CTS). After CTS, changes in gene expression were examined in both groups. Results: Spearman’s correlation analysis revealed that the R/B value was significantly correlated with the KL grade and the Krenn score. The expression levels of genes related to cartilage metabolism, osteogenesis and angiogenesis significantly increased after CTS in the H group, while gene expression in the D group showed weaker changes after CTS than that in the H group compared to the nonstretched control group. Conclusions: The degree of labral degeneration could be classified histologically using the R/B value and the KL grade. Mechanical stretching caused changes in gene expression that support the pathological features of labral degeneration.

‘Mini-Max’ knotless acetabular labrum repair: repair construct rationale and allocation in a consecutive case series with minimum 1-year clinical outcomes

ABSTRACT To describe the ‘mini-Max’ approach to labrum repair using non-absorbable 2.4-mm knotless suture anchors and report objective clinical outcomes with a large single-surgeon cohort. Level 3 retrospective case series. A retrospective review was conducted to report the use and allocation of non-absorbable 2.4-mm knotless suture anchors during ‘mini-Max’ labral repair from 2015 to 2018. Descriptive analysis of the labral damage severity, size and number of anchors used to arthroscopically repair the acetabular labrum was performed. Paired-samples t-tests were performed to evaluate whether preoperative and 1-year follow-up patient-reported outcomes (PROs) were statistically significant. An analysis of variance was performed comparing PROs with categorized number of labral anchors. A total of 390 patients were queried in this study, with 330 (85%) diagnosed intraoperatively with acetabular labral tears. A total of 245 patients (137 females and 108 males) with a mean age of 30.1 ± 11.6 years (mean ± SD) at the time of surgery underwent ‘mini-Max’ labral refixation. Of the 245 labral tears, 88 (35.9%) were graded as mild, 113 (46.1%) as moderate and 44 (18.0%) as severe. Labral repairs required an average of 2.1 ± 0.67 anchors across all patients included. Forty-one repairs (16.7%) required one anchor, 139 (56.7%) required two anchors, 63 (25.7%) required three anchors and 2 (0.8%) required four anchors. Significant improvements were reported for all PROs (P ≤ .001) at a minimum of 1-year follow-up. Arthroscopic ‘mini-Max’ labral repair using non-absorbable knotless suture anchors is a safe and effective technique for improving the lives of patients suffering from symptomatic acetabular labrum tears.

The imaging evaluation of acetabular labral lesions

The acetabular labrum is an important structure that contributes to hip joint stability and function. Diagnosing labral tears involves a comprehensive assessment of clinical symptoms, physical examinations, imaging examinations, and arthroscopic confirmation. As arthroscopy is an invasive surgery, adjuvant imaging of the acetabular labrum is increasingly imperative for orthopedists to diagnose and assess labral lesions prior to hip arthroscopy for surgical management. This article reviews the current imaging strategies for the evaluation of labrum lesions.