Cartilage signal intensity on T1-weighted MRI: association with risk factors and measures of knee osteoarthritis

Clinical Outcomes After Autologous Chondrocyte Implantation in Adolescents' Knees: A Systematic Review

PURPOSE

To perform a systematic review of the use of autologous chondrocyte implantation (ACI) in the adolescent knee.

SPECIFIC AIMS

(1) quantify clinical outcomes of ACI in adolescent knees, (2) identify lesion and patient factors that correlate with clinical outcome, and (3) determine the incidence of complications of ACI in adolescents.

METHODS

PubMed, MEDLINE, SCOPUS, CINAHL, and Cochrane Collaboration Library databases were searched systematically. Outcome scores recorded included the International Knee Documentation Committee score, the International Cartilage Repair Society score, the Knee Injury and Osteoarthritis Outcome Score, the visual analog scale, the Bentley Functional Rating Score, the Modified Cincinnati Rating System, Tegner activity Lysholm scores, and return athletics. Outcome scores were compared among studies based on proportion of adolescents achieving specific outcome quartiles at a minimum 1-year follow-up. Methodologic quality of studies was evaluated by Coleman Methodology Scores (CMSs).

RESULTS

Five studies reported on 115 subjects who underwent ACI with periosteal cover (ACI-P; 95, 83%), ACI with type I/type III collagen cover (ACI-C; 6, 5%), or matrix-induced ACI (MACI; 14, 12%). Mean patient age was 16.2 years (range, 11 to 21 years). All studies were case series. Follow-up ranged from 12 to 74 months (mean, 52.3 months). Mean defect size was 5.3 cm(2) (range, 0.96 to 14 cm(2)). All studies reported improvement in clinical outcomes scores. Graft hypertrophy was the most common complication (7.0%). The mean preoperative clinical outcome percentage (based on percentage of outcome scale used) was 37% (standard deviation [SD], 18.9%) and the mean postoperative clinical outcome percentage was 72.7% (SD, 16.9%). The overall percentage increase in clinical outcome scores was 35.7% (SD, 14.2%). Mean CMS was 47.8 (SD, 8.3).

CONCLUSIONS

Cartilage repair in adolescent knees using ACI provides success across different clinical outcomes measures. The only patient- or lesion-specific factor that influenced clinical outcome was the shorter duration of preoperative symptoms.

LEVEL OF EVIDENCE

Level IV, systemic review of Level I-IV studies.

Correlation between histological outcome and surgical cartilage repair technique in the knee: A meta-analysis

BACKGROUND

Compare histological outcomes after microfracture (MF), autologous chondrocyte implantation (ACI), and osteochondral autograft transfer (OATS).

METHODS

Literature review using PubMed MEDLINE, SCOPUS, Cumulative Index for Nursing and Allied Health Literature (CINAHL), and Cochrane Collaboration Library. Inclusion criteria limited to English language studies International Cartilage Repair Society (ICRS) grading criteria for cartilage analysis after ACI (autologous chondrocyte implantation), MF (microfracture), or OATS (osteochondral autografting) repair techniques.

RESULTS

Thirty-three studies investigating 1511 patients were identified. Thirty evaluated ACI or one of its subtypes, six evaluated MF, and seven evaluated OATS. There was no evidence of publication bias (Begg's p=0.48). No statistically significant correlation was found between percent change in clinical outcome and percent biopsies showing ICRS Excellent scores (R(2)=0.05, p=0.38). Percent change in clinical outcome and percent of biopsies showing only hyaline cartilage were significantly associated (R(2)=0.24, p=0.024). Mean lesion size and histological outcome were not correlated based either on percent ICRS Excellent (R(2)=0.03, p=0.50) or percent hyaline cartilage only (R(2)=0.01, p=0.67). Most common lesion location and histological outcome were not correlated based either on percent ICRS Excellent (R(2)=0.03, p=0.50) or percent hyaline cartilage only (R(2)=0.01, p=0.67).

CONCLUSIONS

Microfracture has poorer histologic outcomes than other cartilage repair techniques. OATS repairs primarily are comprised of hyaline cartilage, followed closely by cell-based techniques, but no significant difference was found cartilage quality using ICRS grading criteria among OATS, ACI-C, MACI, and ACI-P.

LEVEL OF EVIDENCE

IV, meta-analysis.

Change in knee structure and change in tibiofemoral joint space width: a five year longitudinal population-based study

Background

Change in knee cartilage volume is frequently used as a proxy for change in knee joint space width over time, but longitudinal data on these associations is limited. We aimed to determine whether change in knee cartilage volume, new or worsening meniscal extrusion (ME), meniscal tears and cartilage defects over 2.4 years correlated with change in joint space width (JSW) over 5 years in older community dwelling adults.

Methods

Participants (n = 153) had their right knee imaged using MR imaging and x-ray at baseline, and after 2.4 years (MRI) and 5 years (x-ray). Cartilage volume, cartilage defects, meniscal extrusions and meniscal tears were assessed on sagittal T1-weighted fat-suppressed MRI. JSW was assessed using standard fixed semi-flexed view radiographs, and scored on those with adequate alignment.

Results

Participants were 51–79 (mean 62) years old; 48 % were female. Cartilage volume reduced over time (medial −134 ± 202 μL/year, lateral −106 ± 165 μL/year, p < 0.001), as did JSW (medial −0.05 ± 0.16 mm/year, lateral −0.12 ± 0.24 mm/year, p < 0.001). In multivariable analysis, the only consistent predictor of change in JSW was new or worsening ME (medial tibia R² 3.1 %, p = 0.031; medial femur R² 3.2 %, p = 0.024); change in cartilage volume correlated with change in JSW laterally (R² 4.8 %, p = 0.007) and was borderline medially (R² 2.2 %, p = 0.064); there was no association for meniscal tears or cartilage defects. The magnitude of these associations were similar albeit somewhat greater for ME in participants with radiographic OA (R² 6.2 %, p = 0.017).

Conclusion

Change in ME and cartilage volume weakly predict change in JSW, but the vast majority of the variation remains unexplained. Since MRI examines cartilage directly while radiographs examine it indirectly, these results cast doubt on the validity of using JSW as a proxy measure of cartilage loss.