Poster 104: Rates of Achieving Meaningful Outcomes and Predictors of Clinical Failure 5-Years After Undergoing Microfracture Augmented with Allograft Cartilage For Treatment of Hip Chondral Defects

Abstract

Objectives:

Recently, a biologic scaffold combining allograft cartilage and autologous platelet-rich plasma (BioCartilage®) has been introduced to augment microfracture treatment of symptomatic chondral defects of the hip. The purpose of the study is to evaluate rates of achieving meaningful outcomes and clinical failure at 5-year after undergoing microfracture augmented with BioCartilage for treatment of full-thickness cartilage defects in the hip, and to identify variables predictive of requiring clinical failure.

Methods:

Data from a prospective series of consecutive patients with Outerbridge grade IV chondromalacia of the acetabulum or femoral head who underwent hip microfracture augmented with BioCartilage between January 2017 and August 2019 was analyzed. Patient-reported outcomes were collected preoperatively and at minimum five-year postoperatively. The Hip Outcome Score- Activity of Daily Living (HOS-ADL), -Sports Subscale (HOS-SS), modified Hip Harris Score (mHHS), and Non-Arthritic Hip Score (NAHS) thresholds for achieving the minimal clinically important difference (MCID), patient acceptable symptomatic state (PASS), and substantial clinical benefit (SCB) at 5-year after surgery were calculated. Regression analysis was perfomed to identify whether patient demographics and cartilage defect size was predictive of clinical failure.

Results:

A total of 79 patients (84%) had 5-year follow up, and were included in the final analysis. The combined mean age and BMI was 37.1+10.1 years and 27.1+4.5, respectively, and had a mean follow-up time of 69.9+8.7 months. The average chondromalacia area was 193.6+103.9, with 70 patients (94.6%) and 13 The average acetabular head and femoral chondromalacia area treated was 201.8+111.3mm² and 164+70.6mm², respectively. There was a statistically significant improvement in all functional score averages over the 5-year time period (p<0.05). A total of 84.6%, 87.9%, and 77.3% reached at least one threshold for achieving MCID, PASS, or SCB respectively. Of the 79 hips in the analysis, 12(15.2%) underwent conversion to total hip arthroplasty (THA) at an average of 31.3+21.7 months from hip arthroscopy. Regression analysis demonstratd that size of chondral defect was not statistically associated with conversion to THA, while older age was statistically predictive (p-value: 0.013).

Conclusion:

Patients undergoing microfracture with BioCartilage augmentation for acetabular or femoral head chondromalacia demonstrated high rates of achieving meaningful outcome at 5-year follow-up regardless of chondromalacia defect size. In this group, age was shown to be a predictor of conversion to THA within the follow-up time period. While 15.2% required conversion to THA, the majority of patients achieved clinical success indicating this novel technique provides good mid-term outcomes.