Patellofemoral cartilage restoration procedures results in significant clinical outcomes improvement with a low rate of complications.
There are many treatment options with existing clinical data for treating cartilage lesions in the patellofemoral (PF) joint. However, there are limited studies comparing results between treatment options. The purpose of this systematic review and meta-analysis was to summarize and compare results between PF cartilage restoration techniques.
Analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines utilizing Pubmed, EMBASE, and The Cochrane Library databases on October 8, 2018. Three groups of words related to defect morphology, location, and procedure were searched; and such articles were to include at least one term from each group. Inclusion criteria were clinical articles written in the English language with patient reported outcomes (PROs) after PF cartilage restoration surgery. The minimum follow-up allowed in this study was 12 months. Articles were excluded when PF lesions were not reported separately from lesions of other locations. Article quality was evaluated utilizing the Coleman Methodology Score (CMS). The techniques were grouped as: osteochondral allograft transplantation (OCA), osteochondral autograft transfer (OAT), chondrocytes cell-based, bone marrow aspirate concentrate (BMAC)-based, and scaffold-based. A meta-analysis was performed using the Metafor package as part of RStudio software version 1.0.143.
There was a final number of 59 articles reported in this study that satisfied the inclusion criteria. There were 1,937 knees (1,147 patella lesions, 390 trochlear lesions, and 179 bipolar lesions; 221 lesions did not specify location within the PF joint). The frequency of procedures performed was in decreasing order: chondrocyte cell-based therapy (N=1274; 65.7%), BMAC (N=334, 17.2%), OAT (N=156; 8%), OCA (N=129; 6.6%) and scaffold (N=44; 2.2%). In comparison to the overall pooled lesion size (3.9cm2, 95% CI: 3.5 – 4.3cm2), scaffold and OAT had significantly smaller lesion size (p<0.001) while chondrocyte-based had significantly greater lesion size (p=0.039). Statistically significant improvement was observed on at least one PRO in chondrocyte cell-based (22 papers, 64.7%), BMAC (4 papers, 40%), OAT (4 papers, 50%), OCA (5 papers, 71.4%) and scaffold (1 paper, 50%). There was no significant difference observed between any of the groups and the overall pooled change in IKDC score (30.2, 95% CI: 27.4 – 32.9) and Lysholm (25.2, 95% CI: 16.9 – 33.5). No significant difference was observed between any subgroup and the overall pooled minor complication rate (8.3%, 95% CI: 5.3 – 12.8%) and overall pooled major complication rate (7.6%, 95% CI: 5.2 – 11.0%). In comparison to the overall pooled failure incidence, OCA procedures had a significantly greater incidence of failure (6.7%, 95% CI: 4.7 – 9.5%). The level of evidence (LOE) breakdown was as follows: I (n=0), II (n=12), III (n=3), IV (n=44). The average CMS score was 71.76.
The most common cartilage restoration procedures performed in the PF joint are chondrocyte-based. The majority of studies report significant improvement in clinical outcomes with no significant differences in the changes in the IKDC score and Lysholm score between techniques. There is a low rate of minor complications, major complications, and failures within all techniques.