Autologous Chondrocyte Implantation to Isolated Patella Cartilage Defects

Abstract

Background. Autologous chondrocyte implantation (ACI) is a durable treatment for patients with chondral defects. This study presents the comprehensive evaluation of patients with patella defects treated with ACI at medium-to long-term follow-up. Methods. Thirty consecutive patients with isolated chondral lesions of the patella were enrolled prospectively. Primary outcome measures were validated patient reported outcome measures and objective magnetic resonance imaging. Results. Nineteen of 30 patients underwent tibial tubercle osteotomy (TTO) to correct lateral maltracking in combination with soft tissue balancing. The defect sizes were large, averaging 4.7 ± 2.1 cm 2 (range 2.2-30.0 cm 2 ). Pidoriano/Fulkerson classification revealed that 3 defects were type II (lateral), 9 were type III (medial), and 18 were type IV (central/panpatella). Age at the time of surgery was 32 ± 10 years. At follow-up of 2 to 14 years, knee function was rated good to excellent in 25 (83%) patients, fair in 4 (13%) patients, and poor in 1 (3%) patient. Three patients failed treatment after a mean of 75 months (6.25 years). All 3 failures were Workers Compensation (WC) cases. They were older than the non-WC patients, 42 ± 6 years compared with the non-WC 28 ± 9 years (P = 0.0019). Significant increases in all clinical and health utility outcome scores were seen. Magnetic resonance imaging demonstrated that the fill grade, surface and integrity of the repair tissue correlated with clinical scores. Conclusion. ACI to isolated patella defects results in significant functional improvement at a minimum of 24 months, with the results remaining durable at latest follow-up of 15 years. Level of evidence. Level 4.

Patellofemoral Cartilage Repair

“…A total of 84% of patients had good or excellent results after a minimum of 4-year follow-up. Similar results were obtained by von Keudell et al [ 21 ••], showing that 83% of patients had good or excellent functional outcomes after ACI to isolated chondral lesions of the patella with a failure rate of 10% after 15 years of follow-up. As previously mentioned, lateral facet or inferior pole patellar lesions should be addressed with ACI in combination with an anteromedializing TTO to achieve improved outcomes [ 17 , 19 , 67 •].…”

An Expert Consensus Statement on the Management of Large Chondral and Osteochondral Defects in the Patellofemoral Joint

“…Associated patellofemoral instability should be addressed with patellar stabilization procedures concomitantly or before the cartilage restoration procedure. 35,46,81,85,89 3.57 96.43…”

“…76 Several authors later reported comparable results, acknowledging the importance of correcting maltracking before or concurrently with the cartilage procedures. 35,46,81,85,89 Both ACI and OCA were considered valid treatments for large chondral defects in the patella and trochlea except in cases of end-stage osteoarthritis and/or restricted range of motion (<100 -110 ). While end-stage arthritis is a contraindication to cartilage repair, subtotal loss or bipolar lesions without significant joint space narrowing can be treated with ACI or OCA, especially in young patients.…”

Cartilage Restoration of Patellofemoral Lesions: A Systematic Review

“…The AMIC technique showed repair cartilage with poor quality, high rate of incomplete filling (40% to 60%), graft hypertrophy (20% to 40%) and irregular surface and incomplete integration into the border zone (20% to 60%). 44,46 ACI technique had the best quality of cartilage among the cell-based techniques, with a high rate of moderate-to-high defect filling (>50%) in more than a half of patients, complete integration of the graft in more than half of the patients, 15,17,57,61,62 with smooth surface (84% to 91%), 17,62 intact surface without irregularities (58%), 57 high incidence of homogenous structure 17,62 and hypointense or isointense signal. 17,57,62 In addition, a lower rate of graft hypertrophy was seen as compared with other techniques.…”

“…56 MRI findings demonstrated high rates of moderate to high defect filling (>50%) in 55% to 100% of patients and graft hypertrophy in 0% to 33% of patients (n = 135 out of 191). 15,17,56,57,61,62 Complete integration to the border zone was found in 47% up to 88% of patients (n = 135 out of 191), 15,17,57,61,62 with 84% to 91% with smooth surface or focal changes (n = 48 out of 91) 17,62 and 58% with intact surface without irregularities (n = 24 out of 31). 57 The structure of the repair tissue was homogeneous in 21% to 58% of patients in 2 studies (n = 58 out of 68) 15,57 and 85% to 95% had more than 50% of homogenous repaired structure in 2 other studies (n = 48 out of 91).…”