Minimum 10-Year Clinical and Radiological Outcomes of a Randomized Controlled Trial Evaluating 2 Different Approaches to Full Weightbearing After Matrix-Induced Autologous Chondrocyte Implantation

Abstract

Background: Longer term outcomes after matrix-induced autologous chondrocyte implantation (MACI) are lacking, while early postoperative weightbearing (WB) management has traditionally been conservative. Purpose: To investigate the longer term clinical and radiological outcomes after an 8-week (vs 12-week) WB protocol after MACI. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A randomized study design allocated 70 patients to an 8- (n = 34) or 12-week (n = 36) approach to full WB after MACI of the medial or lateral femoral condyle. Patients were evaluated preoperatively; at 3, 12, and 24 months after surgery; and at 5 and 10 years after surgery. At 10 years (range, 10.5-11.5 years), 60 patients (85.7%; 8 weeks: n = 29; 12 weeks: n = 31) were available for review. Clinical outcomes included patient-reported outcomes, maximal isokinetic knee extensor and flexor strength, and functional hop capacity. High-resolution magnetic resonance imaging (MRI) was undertaken to assess the quality and quantity of repair tissue per the MOCART (magnetic resonance observation of cartilage repair tissue) system. A combined MRI composite score was also evaluated. Results: Clinical and MRI-based scores for the full cohort significantly improved ( P < .05) over the 10-year period. Apart from the Tegner activity score, which improved ( P = .041), as well as tissue structure ( P = .030), which deteriorated, there were no further statistically significant changes ( P > .05) from 5 to 10 years. There were no 10-year differences between the 2 WB rehabilitation groups. At 10 years, 81.5% and 82.8% of patients in the 8- and 12-week groups, respectively, demonstrated good-excellent tissue infill. Graft failure was observed on MRI at 10 years in 7 patients overall, which included 4 located on 10-year MRI (8 weeks: n = 1; 12 weeks: n = 3) and a further 3 patients (8 weeks: n = 1; 12 weeks: n = 2) not included in the current analysis who proceeded to total knee arthroplasty. At 10 years, 93.3% of patients were satisfied with MACI for relieving their pain, with 83.3% satisfied with their ability to participate in sport. Conclusion: MACI provided high satisfaction levels and tissue durability beyond 10 years. The outcomes of this randomized trial demonstrate a safe 8-week WB rehabilitation protocol without jeopardizing longer term outcomes.

Long-term Prospective Clinical and Magnetic Resonance Imaging–Based Evaluation of Matrix-Induced Autologous Chondrocyte Implantation

“…The MACI procedure is a 2-stage surgical technique and has been described previously. 8,13 Via an initial arthroscopic procedure a sample of articular cartilage was harvested and chondrocytes subsequently isolated, cultured (Genzyme), and seeded onto a type I/III collagen membrane (ACI-Maix; Matricel GmbH) ex vivo over a 6- to 8-week period. In a second surgical procedure via an open arthrotomy, the cartilage defect was prepared by removing all damaged cartilage down to the subchondral bone.…”

“…5,6,10,11,17,35 However, only limited studies are available reporting outcomes for third-generation ACI techniques beyond 10 years, with these generally including smaller patient cohorts and/or lacking postoperative MRI evaluation. 1,8,18,26 Published third-generation studies by Aldrian et al, 1 Gille et al, 18 and Niethammer et al 26 reported outcomes at ≥10 years in 16, 18, and 30 patients, respectively. The largest 10-year cohort published recently was in 60 patients, although it was isolated to grafts in the tibiofemoral joint (medial and lateral femoral condyles [MFCs and LFCs]).…”

“…The largest 10-year cohort published recently was in 60 patients, although it was isolated to grafts in the tibiofemoral joint (medial and lateral femoral condyles [MFCs and LFCs]). 8…”

A Translational Porcine Model for Human Cell–Based Therapies in the Treatment of Posttraumatic Osteoarthritis After Anterior Cruciate Ligament Injury

“…Fibrin glue is currently readily available for human applications and has a strong track record of being successfully applied clinically to support cell-based therapies within the human knee joint. 8,12,13 Fibrin glue is the recommended product used to facilitate matrix-induced autologous chondrocyte implantation, a cartilage restoration therapy approved by the FDA for use in humans. In addition, the ability to use human cells rather than nonhuman cells for efficacy experiments in this porcine model increases the translational potential of this approach.…”

Postoperative Management for Articular Cartilage Surgery in the Knee

“…In studies comparing WB progression after MACI, patients who progressed to weight bearing as tolerated (WBAT) by 6 to 8 weeks as compared with 10 to 12 weeks were reported to have improved clinical and functional outcomes without an increase in failure rate. 45,46 However, ACI should progress WB activities more cautiously than MACI, with partial (one-fourths body weight) WB initiated at 2 to 4 weeks and gradually increased to WBAT by 8 to 12 weeks. 39,42,43 The use of an unloader brace may be indicated for larger tibiofemoral lesions, and can aid in the reduction of compressive forces on treated sites during WB activities.…”