Background: High tibial osteotomy (HTO) is a method used to treat medial compartmental osteoarthritis in the knee. The realignment of the knee changes the loading patterns within the joint and may allow for regeneration of articular cartilage. Magnetic resonance imaging methods can be used to assess the quality of the regenerated cartilage.
Hypothesis: Altering mechanical alignment through HTO will have predictable effects on articular cartilage, allowing cartilage preservation and possible regeneration. Quality of regenerated cartilage will be inferior to normal articular cartilage.
Study Design: Case series; Level of evidence, 4.
Methods: Ten patients undergoing medial opening wedge HTO were evaluated using dGEMRIC methods (ie, delayed gadolinium-enhanced magnetic resonance imaging of cartilage) preoperatively and at 6 months, 1 year, and 2 years after HTO. Magnetic resonance images were evaluated by hand segmentation, and T1Gd relaxation times reflective of glycosaminoglycan content were determined for these regions of interest using magnetic resonance imaging analysis software.
Results: The lateral compartment displayed higher T1Gd values than the medial compartment at baseline. Initially, a decrease in T1Gd values on the medial side were observed for all patients at 6 months and remained reduced for all but 2 participants at 1 year and 2 years after HTO. However, on the medial side after 6 months, the rate of change for T1Gd values shifted from being negative (–9.6 milliseconds per month) to being positive (1.7 milliseconds per month). A positive change in the T1Gd of the medial tibial plateau was responsible for the positive overall change in the medial compartment. There was no significant difference in the rate of change on the lateral side (P = .141), with the average over the 2-year period being a decrease of 2.28 milliseconds per month.
Conclusion: Medial opening wedge HTO provides subjective improvements in pain and quality of life, but the potential benefit of allowing articular cartilage preservation and possible regeneration is not well established. Results showed that after a nonweightbearing period, the rate of change in the medial compartment changes from negative to positive, indicating the potential for articular cartilage recovery secondary to an improved mechanical environment.
Background
Autologous chondrocyte implantation (ACI) is frequently used to treat symptomatic defects of the articular cartilage.
Purpose
To test whether matrix-associated autologous chondrocyte implantation or the original periosteal flap technique provides superior outcomes in terms of clinical efficacy and safety.
Study Design
Randomized controlled trial; Level of evidence, 2.
Methods
Twenty-one patients (mean age, 29.3 ± 9.1 years) with symptomatic isolated full-thickness cartilage defects (mean 4.1 ± 09 cm2) at the femoral condyle were randomized to matrix-associated autologous chondrocyte implantation or the original periosteal flap technique. The primary outcome parameter was the postoperative change in knee function as assessed by the International Knee Documentation Committee (IKDC) score at 12 months after ACI. In addition, the IKDC score was assessed at 3, 6, 12, and 24 months after surgery. Secondary outcome parameters were postoperative changes in health related quality of life (Short Form-36 Health Survey), knee functionality (Lysholm and Gillquist score), and physical activity (Tegner Activity Score) at 3, 6, 12, and 24 months after ACI. Magnetic resonance imaging was performed to evaluate the cartilage 6, 12, and 24 months after ACI and rated using the Magnetic Resonance Observation of Cartilage Repair Tissue score. Adverse events were recorded to assess safety.
Results
The primary outcome parameter showed improvement of patients 1 year after autologous chondrocyte implantation, but there was no difference between the periosteal flap technique and matrix-associated ACI (P = .5573); 2 years after ACI, a similar result was found (P = .4994). The study groups did not show differences in the Short Form-36 categories and in knee functionality as assessed by Tegner Activity Score 12 months (P = .4063) and 24 months (P = .1043) after ACI. There was a significant difference in the Lysholm and Gillquist score at 12 months (P = .0449) and 24 months (P = .0487) favoring the periosteal flap technique group. At 6 months after surgery, a significantly lower Magnetic Resonance Observation of Cartilage Repair score was obtained in the matrix-associated ACI group (P = .0123), corresponding to more normal magnetic resonance imaging diagnostic findings. Twelve and 24 months after ACI, the differences between the 2 groups were not significant (12 months, P = .2065; 24 months, P = .6926). Adverse events were related to knee problems such as transplant delamination, development of an osseous spur, osteochondral dissection, and transplant hypertrophy. Systemic (allergic, toxic, or autoimmune) reactions did not occur.
Conclusion
There was no difference in the efficacy between the original and the advanced ACI technique 12 and 24 months after surgery regarding International Knee Documentation Committee, Tegner Activity Score, and Short Form-36; however, with respect to the Lysholm and Gillquist score, better efficacy was observed in the periosteal flap technique group.
