Evaluating Joint Morbidity after Chondral Harvest for Autologous Chondrocyte Implantation (ACI): A Study of ACI-Treated Ankles and Hips with a Knee Chondral Harvest

Abstract

Objective: To establish if harvesting cartilage to source chondrocytes for autologous chondrocyte implantation (ACI) results in donor site morbidity.

Design: Twenty-three patients underwent ACI for chondral defects of either the ankle or the hip. This involved cartilage harvest from the knee (stage I), chondrocyte expansion in the laboratory and implantation surgery (stage II) into the affected joint. Prior to chondral harvest, no patient had sought treatment for their knee. Lysholm knee scores were completed prior to chondral harvest and annually post-ACI. Histological analyses of the donor site were performed at 12.3 ± 1.5 months for 3 additional patients who had previously had ACI of the knee.

Results: The median preoperative Lysholm score was 100, with no significant differences observed at either 13.7±1.7 months or 4.8±1.8 years postharvest (median Lysholm scores 91.7 and 87.5, respectively). Patients whose cartilage was harvested from the central or medial trochlea had a significantly higher median Lysholm score at latest follow-up (97.9 and 93.4, respectively), compared with those taken from the intercondylar notch (median Lysholm score 66.7). The mean International Cartilage Repair Society (ICRS) II histological score for the biopsies taken from the donor site of 3 additional knee ACI patients was 117 ± 10 (maximum score 140).

Conclusions: This study suggests that the chondral harvest site in ACI is not associated with significant joint morbidity, at least up to 5 years postharvest. However, one should carefully consider the location for chondral harvest as this has been shown to affect knee function in the longer term.

Keywords: autologous chondrocyte implantation; cartilage repair; donor-site morbidity; histology; osteoarthritis.

Figure 1.

Box and whisker plots displaying (A) Lysholm scores for the following time points: preoperative, 13.7 ± 1.7 months postharvest (first annual review), and at 4.8 ± 1.8 years postharvest (latest follow-up) and (B) median difference in Lysholm scores at the first annual review and latest follow-up compared with preoperative scores. Lysholm scores at the first annual review (median 91.7) and at latest follow-up (median 87.5) were not significantly different to preoperative scores and neither was the difference in Lysholm score. The box and the horizontal line represent the interquartile range (IQR) and the median, respectively. Outliers are represented as a small triangle.

Figure 2.

Histograms depicting the 7 different scoring parameters of the modified Lysholm score and the percentage of patients within each category preoperatively (dark gray bar), at the first annual review (light gray bar), and the latest follow-up (white bar). A significantly higher occurrence of pain was reported by patients at the latest follow-up compared with preoperatively (P = 0.05) and significantly more catching and locking sensations were reported at both the first annual review and latest follow-up (P = 0.004 and P = 0.019, respectively).

Figure 3.

Box and whisker plots comparing Lysholm scores for different donor sites preoperatively (A), at first annual review (B), and at latest follow-up (C). Lysholm scores were not significantly different from each other preoperatively or at first annual review, but at the latest follow-up, the Lysholm score of patients who had chondral harvest from the intercondylar notch, had significantly lower scores than patients with harvests taken from the central trochlea (**P = 0.01) and the medial trochlea (*P = 0.02). Actual Lysholm scores for the lateral condyle at the 3 time points are represented as small crosses. The box and the horizontal line represent the interquartile range (IQR) and the median, respectively. Outliers are represented as a small triangle.

Figure 4.

Representative arthroscopic image of the donor site in a patient 11 months post–cell implantation for autologous chondrocyte implantation (ACI) of the knee. The white portion in the center of the image (black arrow) is the repaired cartilage in the center of the trochlea, observed to be smooth and well integrated into the surrounding cartilage.

Figure 5.

Representative histological images of a full depth repair tissue biopsy from the donor site in a patient 11 months post–cell implantation for autologous chondrocyte implantation (ACI) of the knee, stained with hematoxylin and eosin (H&E) (A) and toluidine blue (TB) (B). Histological analysis of the repair cartilage demonstrated good matrix metachromasia (B) and good integration into the subchondral bone (C, higher powered image of dashed-line box region in A). Polarized light revealed a mixture of hyaline cartilage and fibrocartilage (D, polarized image of C, f = fibrocartilage, h = hyaline cartilage, b = bone) also well integrated with each other. All biopsies demonstrated a good surface (E, higher power image of the solid line box region in A). Immunohistochemistry of sections demonstrate the widespread presence of type I collagen (F) but more restricted type II collagen in the lower region (G). Scale bars represent 500 µm (A, B, F, G) and 250 µm (C-E).