# Outcomes of autologous chondrocyte transplantation (ACT) and autologous matrix-induced chondrogenesis (AMIC) in the hip: a systematic review and meta-analysis

## TL;DR

This study compares two hip cartilage repair techniques, finding that AMIC leads to better outcomes than ACT based on patient-reported results and success rates.

## Contribution

The study provides a systematic review and meta-analysis of ACT and AMIC outcomes specifically for hip chondral lesions, which are less studied than knee treatments.

## Key findings

- AMIC showed a higher pooled success rate (99.6%) compared to ACT (98.3%).
- Both ACT and AMIC significantly improved patient-reported outcomes like mHHS.
- AMIC is suggested as a preferable treatment due to its better success rate and outcomes.

## Abstract

Appropriate treatment of chondral lesions in the hip greatly improves symptoms and reduces the need for early joint replacement in these patients. Whilst the outcomes of Autologous Chondrocyte Transplantation (ACT) and Autologous Matrix Induced Chondrogenesis (AMIC) in the knee have been thoroughly researched, data on these treatments in the hip is comparatively limited.

To evaluate the outcomes of ACT and AMIC in the hip.

Following PRISMA guidelines, a literature search was performed using free text and MeSH terms relating to ACT, AMIC, and variations of these terms across 6 databases. This resulted in 506 abstracts, which were screened down to 12 papers which met the eligibility criteria. Weighted means and pooled estimates using a random effects model were used to assess the success of both procedures.

628 hips were identified within 12 papers. Weighted mean age 35.8 years (18–55 years), weighted mean lesion size 3.3 cm2 (2.2–5.1 cm2)., weighted mean follow-up 46.9 months (6–96 months). Improvement in mHHS was measured for both interventions, with a mean improvement of 31.1 points following ACT and 35.8 following AMIC. The pooled success rate for AMIC (99.6% [95% CI, 99.0-100.0%]) was higher than that for ACT (98.3% [95% CI, 96.4-100.0%]). All PROs assessed showed statistically significant postoperative improvements.

Both techniques produced significant improvements from baseline. Due to the treatment characteristics, we suggest AMIC is a preferable treatment to ACT. Further research is required to assess the limitations of these procedures concerning chondral lesion size and duration of symptom improvement.

The online version contains supplementary material available at 10.1186/s13018-025-05862-5.