Purpose.: To present preliminary clinical experience with Matrix-induced autologous chondrocyte implantation, a new tissue-engineering technique for treatment of deep cartilage defects, in which autologous chondrocytes are seeded on a tridimensional scaffold provided by a bilayer type I–III collagen membrane. Methods.: From December 1999 to January 2001, 13 patients underwent implantation procedure for deep cartilage defects. Age of patients ranged from 18 to 49 years (mean age, 35 years). The mean defect size was 3.5 cm² (range, 2.0–4.5 cm²). Clinical and functional evaluation were performed using various score systems for the ankle and the knee, and magnetic resonance imaging was performed at 6 and 12 months postoperatively. Membrane structure and cellular population were investigated by light microscopy, scanning electron microscopy, and electrophoresis before implantation. Results.: The mean follow-up was 6.5 months (range, 2–15 months). No complications were observed in the postoperative period. The 6 patients with a minimum follow-up of 6 months showed an improvement in clinical and functional status after surgery. Magnetic resonance images showed the presence of hyaline-like cartilage at the site of implantation; there was evidence of chondroblasts and type II collagen inside the seeded membrane. Conclusion.: Matrix-induced autologous chondrocyte implantation offers several advantages with respect to the traditional cultured cell procedure. These include technical simplicity, short operating time, minimal invasiveness, and easier access to difficult sites. It appears to be a reliable method for the repair of deep cartilage defects.

Background: Several medial patellofemoral ligament reconstruction procedures have been proposed to manage recurrent patellar dislocation. Hypothesis: Reconstruction of the medial patellofemoral ligament using a hamstring graft with a 2 transverse patellar tunnels technique is an effective treatment for recurrent patellar dislocation in patients without any evident predisposing factors. Study Design: Case series; Level of evidence, 4. Methods: Twenty-eight patients with chronic patellar instability without any anatomic predisposing factors, experiencing recurrent unilateral patellar dislocation, were included in the study. Evaluation included the modified Cincinnati and the Kujala scores, anthropometry, plain radiography, and isokinetic dynamometry. Results: The average follow-up was 3.1 years (range, 2.5-4 years). The mean modified Cincinnati score increased from 52 preoperatively to 89 (P = .001). The mean Kujala scores increased from 45 preoperatively to 83 (P = .03). The muscle volume of the thigh of the operated limb increased with time, but remained less well developed than the nonoperated limb (P = .04). The mean Insall-Salvati index was 1.1 (range, 0.9-1.2) preoperatively and remained within normal range (1.1 [range, 0.9 to 1.2]) (P = .07), at latest follow-up. Significant isokinetic strength differences were found between the operated and the contralateral limbs (.05 < P < .006), even at the latest follow-up. Three patients experienced a new patellar dislocation. Conclusion: Medial patellofemoral ligament reconstruction using hamstring tendon passed through a double patellar transverse bony tunnel technique is a safe, reliable management option for recurrent patellar dislocation in patients without any predisposing anatomic factors.

The rupture with specimens harvested from an apparently healthy area in the same tendon. We compared gene expression of collagen Type I, decorin, and versican including enzymes involved in their metabolism as matrix metalloproteases (MMP-2 and -9) and tissue inhibitory of metalloproteinase (TIMP-1 and -2) using real-time PCR, zymography and FACE analysis. We found greater gene expression of proteoglycan core protein decorin and versican, collagen Type I, MMPs and TIMPs in the tendon rupture. Zymography analysis, reflecting expression of enzymatic activity, confirmed the gene expression data at protein level. Carbohydrate content was greater in the macroscopically healthy area than in the ruptured area. In the ruptured area, we found increased core protein synthesis but without the normal glycosaminoglycan production. The tissue in the area of rupture undergoes marked rearrangement at molecular levels and supports the role of MMPs in the pathology....