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

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

PURPOSE

Patients 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.

METHODS

A 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.

RESULTS

Forty-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).

CONCLUSION

Patients 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 EVIDENCE

Level III case-control study.

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

PURPOSE

The 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.

METHODS

A 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.

RESULTS

A 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.

CONCLUSIONS

M-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 EVIDENCE

Level III.

Single-Stage Combined Autologous-Allogenic Cartilage Restoration: Surgical Technique

Articular cartilage injuries in young patients pose a notable treatment dilemma. Multiple reported techniques exist, although some of the most prominent methods currently rely on multiple procedures for chondrocyte harvest and colony expansion prior to implantation. The associated cost and effort this requires limits availability on a global basis, which creates a need for a more widely available cartilage procedure. This Technical Note describes a method for cartilage restoration that incorporates autologous chondrocytes in allogenic extracellular matrix, along with biologic augmentation all performed in a single stage.

Minimum 10-Year Outcomes of Matrix-Induced Autologous Chondrocyte Implantation in the Knee: A Systematic Review

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) is an established cell-based therapy for the treatment of chondral defects of the knee. As long-term outcomes are now being reported in the literature, it is important to systematically review available evidence to better inform clinical practice.

PURPOSE

To report (1) subjective patient-reported outcomes (PROs) and (2) the rate of graft failure, reoperation, and progression to total knee arthroplasty (TKA) after undergoing MACI of the knee at a minimum 10-year follow-up.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive search of Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily; Ovid Embase; Ovid Cochrane Central Register of Controlled Trials; Ovid Cochrane Database of Systematic Reviews; and Scopus from 2008 to September 15, 2022, was conducted in the English language. Study eligibility criteria included (1) full-text articles in the English language, (2) patients undergoing a MACI within the knee, (3) clinical outcomes reported, and (4) a minimum 10-year follow-up.

RESULTS

In total, 168 patients (99 male, 69 female; mean age, 37 years [range, 15-63 years]; mean body mass index, 26.2 [range, 18.6-39.4]) representing 188 treated chondral defects at a minimum 10-year follow-up after MACI were included in this review. Significant and durable long-term improvements were observed across multiple PRO measures. Follow-up magnetic resonance imaging (MRI), when performed, also demonstrated satisfactory defect fill and an intact graft in the majority of patients. The all-cause reoperation rate was 9.0%, with an overall 7.4% rate of progression to TKA at 10 to 17 years of follow-up.

CONCLUSION

At a minimum 10-year follow-up, patients undergoing MACI for knee chondral defects demonstrated significant and durable improvements in PROs, satisfactory defect fill on MRI-based assessment, and low rates of reoperation and TKA. These data support the use of MACI as a long-term treatment of focal cartilage defects of the knee.

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)

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.