Background: Regenerative techniques, such as autologous chondrocyte implantation (ACI), have emerged as a potential therapeutic option for the treatment of chondral lesions, aiming to recreate a hyaline-like tissue in the damaged articular surface. The clinical application of the regenerative approach is well documented for different types of scaffold but mostly with an evaluation of the clinical outcome at short-term follow-up.
Purpose: This study was conducted to analyze the clinical outcome obtained with arthroscopic second-generation ACI up to 7 years’ follow-up, to assess the durability of the results, and understand its real potential over time.
Study Design: Case series; Level of evidence, 4.
Methods: Sixty-two consecutive patients, 48 men and 14 women with a mean age of 28.1 ± 11.4 years, affected by chondral lesions of the femoral condyles were enrolled and treated with arthroscopic implantation of the bioengineered tissue Hyalograft C. The average size of the defects was 2.5 ± 1.0 cm2. Patients were evaluated with International Knee Documentation Committee (IKDC), EuroQol visual analog scale (EQ-VAS), and Tegner scores every year for 7 years, and a magnetic resonance imaging evaluation was performed.
Results: A statistically significant improvement was observed in all scores from the basal evaluation to the 84 months’ follow-up. The IKDC subjective score increased from 39.6 ± 15.0 to 73.6 ± 18.8 at 12 months; a further slight improvement was observed at 24 months’ follow-up (76.5 ± 20.7), and then the results were stable and reached a final 7-year value of 77.3 ± 21.5. Seven cases (11%) failed. A better outcome was obtained in young active men, whereas the worst results were found in degenerative lesions or when previous surgery had been performed. Postoperative magnetic resonance imaging studies in 42 cases revealed a complete filling of the cartilage defect in 57% of the lesions, complete integration of the graft in 62% of cases, intact repair tissue surface in 50%, homogeneous repair tissue structure in 43%, and a graft signal-intensity score that was isointense with the adjacent native cartilage in 43% and 48% of the cases in dual T2–fast spin echo and 3-dimensional gradient echo with fat suppression sequences, respectively.
Conclusion: The analysis of this group of homogeneous patients, prospectively evaluated every year for 7 years, shows that this bioengineered approach with the proper indications may offer good and stable clinical results over time.
Background: Autologous chondrocyte implantation (ACI) is an accepted surgical treatment in patients with isolated cartilage defects of the knee. Age has been considered as a limiting factor and the technique has not been recommended in patients older than 40 to 50 years. Nevertheless, some more recent studies report satisfying clinical results in middle-aged patients.
Hypothesis: Analogous to the microfracture technique, age over 40 years is associated with inferior clinical outcome after ACI.
Study Design: Cohort study; Level of evidence, 2.
Methods: Thirty-seven patients with an average age of 47.8 years (group 1) were matched with 37 patients with an average age of 31 years (group 2). Both groups underwent ACI for treatment of isolated cartilage defects of the knee. All patients were enrolled prospectively and followed for a period of 24 months using International Knee Documentation Committee (IKDC), Lysholm scale, Cincinnati sports scale, and Tegner activity evaluation instruments.
Results: Statistical analysis revealed a significant increase in function after ACI in both groups as early as 6 months after surgery until the end of the study period. There was only a slight tendency for better clinical outcome in younger patients (IKDC at 24 months: group 1, 72.2 ± 15.8 [standard deviation]; group 2: 76.1 ± 14.1; P = .261; Lysholm at 24 months: group 1: 80.42 ± 15.37; group 2: 80.65 ± 12.01), no statistical significant differences were found between patients of group 1 and group 2 at any of the time points investigated.
Conclusion: In contrast to other cartilage repair techniques, patients 40 years and older do not have an inferior outcome up to 24 months after ACI for isolated cartilage defects when compared with younger patients.
Background: Mechanical tests to grade cartilage damage are limited by the instruments used and by the ability to access all areas of cartilage within a joint. Better methods to diagnose cartilage injury or degeneration are needed.
Purpose/Hypothesis: To detect the interobserver variance of arthroscopic cartilage grading by subjective judgment using the International Cartilage Repair Society (ICRS) score and by objective measurement using near-infrared (NIR) spectroscopy. We hypothesized that objective measurement of cartilage lesions by NIR spectroscopy will yield more valid results than routine grading using the ICRS score.
Study Design: Cohort study (diagnosis); Level of evidence, 2.
Methods: Fifteen patients undergoing arthroscopic knee operations were evaluated by 4 experienced arthroscopists independently. The cartilage lesions within the medial knee compartment were estimated by each observer using the ICRS grade and by measurements with a special arthroscopic NIR spectroscopy probe.
Results: The ICRS grading had a poor interobserver agreement, with a mean Fleiss kappa index of = 0.173. Only in 10% (6 of 60) of judged cartilage areas did all 4 surgeons grade the cartilage areas with the same result. In 17 areas (28.3%), the surgeons had a variance of 2 or more grades. In the remaining cases, the surgeons varied within 1 grade. The objective NIR spectroscopy-obtained measurements of cartilage resulted in a significant correlation within the observers of R = 0.885 ± 0.036 (P < .001).
Conclusion: Our results of interobserver evaluation in real-time arthroscopic cartilage grading suggest that this subjective grading is not satisfactory. This study emphasizes the need for objective measurement techniques for arthroscopic cartilage grading. Near-infrared spectroscopy has a good interobserver correlation. Thus, this method could be developed in the future as a precise method of measuring cartilage lesions.
Background: Although autologous chondrocyte implantation (ACI) is a well-established therapy for the treatment of isolated cartilage defects of the knee joint, little is known about typical complications and their treatment after ACI.
Hypothesis: Unsatisfactory outcome after ACI is associated with technique-related typical complications.
Study Design: Case series; Level of evidence, 4.
Methods: A total of 309 consecutive patients with 349 ACI procedures of the knee joint were analyzed. Three different ACI techniques were used: periosteum-covered ACI in 52 cases (14.9%), Chondrogide (Geistlich Biomaterials, Wolhusen, Switzerland) membrane-covered ACI in 215 cases (61.6%), and a 3-dimensional matrix-associated ACI (BioSeed-C, Biotissue Technologies, Freiburg, Germany) in 82 cases (23.5%). In 52 patients, revision surgery was performed for persistent clinical problems. These patients were analyzed for defect size and location, technique of ACI, and intraoperative findings during revision surgery. The mean time of follow-up for patients after ACI was 4.5 years (standard deviation, ± 1.5).
Results: Four typical major complications were identified: hypertrophy of the transplant, disturbed fusion of the regenerative cartilage and the healthy surrounding cartilage, insufficient regenerative cartilage, and delamination. These diagnoses covered a total of 88.5% of the patients who underwent revision surgery. The overall complication rate was highest in the group of patients treated with periosteum-covered ACI (P = .008). The incidence of symptomatic hypertrophy was 5.2% for all techniques and defect locations; the highest incidence was in patients treated with periosteum-covered ACI (15.4%) (P = .001). The incidence of disturbed fusion was highest in the Chondrogide-covered ACI (3.7%) and the matrix-associated ACI group (4.8%). Concerning the incidence of complications by defect location, there was a tendency for increased complications in patellar defects (P = .095). Within the patellar defects group, no correlation was found for the occurrence of delamination, insufficient regeneration, and disturbed fusion. As a statistical trend, an increased rate of hypertrophy was found for patellar defects (P = .091).
Conclusion: A major proportion of complications after ACI can be summarized by 4 major diagnoses (symptomatic hypertrophy, disturbed fusion, delamination, and graft failure). Among those, the overall complication rate and incidence of hypertrophy of the transplant were higher for periosteum-covered ACI. Furthermore, an increased rate of symptomatic hypertrophy was found for patellar defects. Therapeutic concepts need to be developed to treat these typical complications of ACI.
