Utilization of Autologous Chondrocyte Implantation in the Knee Is Increasing While Reoperation Rates Are Decreasing Despite Increasing Preoperative Comorbidities

Purpose This study aimed to analyze the risk of reoperation following autologous chondrocyte implantation (ACI) of the knee utilizing third-generation ACI products in a time-to-event analysis and report on the associated patient-reported outcome measures (PROM) in case of reoperation. Methods Patients undergoing ACI were included from a longitudinal database. Patient age, sex, body mass index (BMI), number of previous surgeries, lesion localization, lesion size, symptom duration, as well as time and type of reoperation was extracted. A cox proportional-hazards model was applied to investigate the influence of baseline variables on risk of reoperation. Reoperation was defined as any type of subsequent ipsilateral knee surgery, excluding hardware removal. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was utilized to compare PROM between patients with and without reoperation. Results A total of 2039 patients were included with 1359 (66.7%) having a minimum follow-up of 24 months. There were overall 243 reoperations (prevalence 17.9%). Minor arthroscopic procedures (n = 96, 39.5%) and revision cartilage repair procedures (n = 78, 32.1%) were the most common reoperations. Nineteen patients (0.9%) reported conversion arthroplasty at 17.7 (10.4) months after ACI. Female sex (HR 1.5, 95% CI [1.2, 2.0], p = 0.002) and the presence of 1–2 previous surgeries (HR 1.5, 95% CI [1.1, 2.0], p = 0.010), or more than 2 previous surgeries (HR 1.9, 95% CI [1.2, 2.9], p = 0.004) were significantly associated with increased risk of reoperation following ACI. Significantly less patients surpassed the minimal clinically important difference (MCID) in the reoperation group at 24 months regarding the KOOS subscores pain (OR 1.6, 95% CI [1.1, 2.2]), quality of life (OR 2.2, 95% CI [1.6, 3.2]), symptoms (OR 2.0 [1.4, 2.9]), and sports (OR 2.0 [1.4, 2.8]). Conclusion Female patients and individuals with a history of previous surgeries face an elevated risk of requiring reoperation after undergoing ACI, which is associated with failure to attain clinically relevant improvements. A thorough evaluation of the indications for ACI is paramount, particularly when patients have a history of previous surgeries. Level of evidence Level III.

Section: Discussionsupporting

confidence: 92%

Section: Discussioncontrasting

confidence: 77%

Section: Discussioncontrasting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increased risk of reoperation and failure to attain clinically relevant improvement following autologous chondrocyte implantation of the knee in female patients and individuals with previous surgeries: a time‐to‐event analysis based on the German cartilage registry (KnorpelRegister DGOU)

Bumberger,

Rupp,

Lattermann

et al. 2023

Favourable clinical outcomes and low revision rate after M‐ACI in adolescents with immature cartilage compared to adult controls: Results at 10 years

Weishorn,

Wiegand,

Koch

et al. 2024

PurposeThe purpose of this study was to evaluate long‐term survival, patient‐reported outcomes (PROs) and radiographic results of matrix‐associated autologous chondrocyte implantation (M‐ACI) in adolescents with immature cartilage and compare them to adult controls.MethodsA retrospective matched‐pair analysis was performed comparing the PRO after M‐ACI for focal cartilage defect of the knee in cartilaginous immature adolescents to mature adults. Groups were matched for sex, body mass index, defect site and size, symptom duration and the number of previous knee surgeries. Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART 2.0) scores were assessed at least 60 months postoperatively. Patient acceptable symptomatic state (PASS) and clinical response rate in KOOS and KOOS subscores were calculated.ResultsA total of 54 patients were matched. At a mean of 96 months (65–144 months), no surgical complications, graft hypertrophy or reoperations were noted in the cohorts studied. Adolescents showed superior PROs at the final follow‐up (76.9 ± 14.1 vs. 66.4 ± 15.0, p = 0.03) and were significantly more likely to achieve PASS (74.1% vs. 55.6%; p = 0.02) compared to the adult cohort. The KOOS subscale analysis showed long‐term benefits for adolescents in terms of symptom improvement, pain reduction, activities of daily living, sports and quality of life (p < 0.05). None of the patients in the adolescent group showed graft hypertrophy on magnet resonance imaging or signs of osteoarthritis on radiographs at long‐term follow‐ups.ConclusionsM‐ACI is an effective treatment for chondral defects of the knee in patients with immature cartilage with low revision rates and high patient satisfaction over the long term. Adolescents showed comparable clinical and radiographic results in the short and medium term, with slightly more favourable, clinically relevant functional results in adolescents in the long term. M‐ACI can be safely used in adolescents, and consideration should be given to expanding the indication to include these patients.Level of EvidenceLevel III.

Undergoing cartilage procedures before total knee arthroplasty is not associated with worse postoperative functional outcomes, readmission rates or complication rates

Khan,

Cozzarelli,

Hohmann

et al. 2024

PurposePatients undergoing total knee arthroplasty (TKA) with prior knee cartilage surgery have unclear outcomes in the literature. This study compared outcomes after TKA in patients with or without prior knee cartilage surgery, and we hypothesized there would be equivocal outcomes between groups.MethodsA retrospective matched case–control study was conducted on patients from our institution who underwent ipsilateral cartilage procedure(s) and TKA (cases) or TKA alone (controls) from 2000 to 2022. Cartilage procedures included Autologous Chondrocyte Implantation (ACI), Osteochondral Allograft (OCA) and Microfracture (MFx). Matching was performed in 1:3 (case:control) ratio for age, sex, body mass index, Charlson Comorbidity Index, pre‐TKA Kellgren–Lawrence osteoarthritis grade and follow‐up for knee injury and osteoarthritis outcome score for joint replacement (KOOS‐JR). Mann–Whitney U and χ2 analyses were conducted, with significance being a p < 0.05. A priori power analysis required 29 patients per cohort to reach a clinically detectable difference of 11 for KOOS‐JR.ResultsForty‐three cases (one ACI, eight OCA and 34 MFx) and 129 controls were included after matching, with no significant demographic differences. Cases underwent TKA after cartilage surgery at a mean of 4.6 years. No significant differences existed between cases and controls for the preoperative KOOS‐JR (45.2 vs. 47.8; p = 0.353), postoperative KOOS‐JR (69.8 vs. 69.9; p = 0.974) or Delta KOOS‐JR (30.4 vs. 26.0; p = 0.387). No significant differences existed for 90‐day readmission rates (4.7% vs. 2.3%; p = 0.600) or revision TKA rates (11.6% vs. 5.4%; p = 0.177).ConclusionPatients with and without prior cartilage surgery experience similar functional outcomes, readmission rates and revision rates after TKA on the same knee. Patients who are candidates for TKA with a history of cartilage surgery may be counselled that their surgical history on that knee does not convey the risk of worse functional outcomes.Level of EvidenceLevel III case–control study.