Outcomes of mechanical debridement and radiofrequency ablation in the treatment of chondral defects: a prospective randomized study.

This study compared the clinical and biomechanical outcomes of mechanical debridement with and without monopolar radiofrequency energy in treating chondral defects. Patients who were scheduled for arthroscopic procedures (diagnostic, debridement and lavage, and meniscectomy) and consented to biomechanical cartilage stiffness testing comprised the study population. Patients were randomized into 2 groups. In group 1, 14 patients underwent mechanical debridement only, and in group 2, 15 patients underwent mechanical debridement followed by monopolar radiofrequency. Clinical status was evaluated using the International Knee Documentation Committee (IKDC) subjective knee form. In group 2, the biomechanical properties of the defective cartilage before and after treatment also were evaluated. Findings showed a trend toward improvement in mechanical stiffness of energy-treated chondral lesions. Moreover, no significant differences were found between IKDC scores at average follow-up of 16 to 19 months. The addition of radiofrequency energy, at least in the investigated form, does not add clinically significant benefits over mechanical debridement alone of chondral defects.

Reversal of suppressed metabolism in prolonged cold preserved cartilage.

Chondrocytes in cold preserved cartilage are metabolically suppressed. The goal of this study was to address this metabolic suppression and seek ways to reverse it. Specifically, we examined the roles of rewarming protocols and nitric oxide (NO) in this metabolic suppression. Bovine and canine full-thickness articular cartilage explants were cultured under various temperature conditions, and NO production, proteoglycan (PG) synthesis, and cell viability were measured. Nitric oxide was shown to be negatively correlated with PG synthesis following abrupt rewarming of cold preserved osteochondral allografts. Gradual rewarming of the allograft tissue decreased NO production with higher PG synthesis. Inhibition of nitric oxide synthases (NOS) led to a decrease in NO production and a concomitant increase in PG synthesis. We were able to partially reverse metabolic suppression of cold preserved osteochondral allograft material with gradual rewarming and decrease NO production with NOS inhibition. Chondrocytes in cold preserved allograft material may be metabolically suppressed predisposing the graft to failure in vivo. Minimizing this loss of metabolic function by gradual graft rewarming and decreasing NO production by NOS inhibition at the time of graft implantation may have implications on graft survival in vivo.

Impaction affects cell viability in osteochondral tissues during transplantation.

Symptomatic full-thickness defects of articular cartilage are increasingly treated with osteochondral allografts. The present study focused on the viability of cells in cartilage that had been impact loaded by the instruments used in preparation of the cartilage for transplantation. Osteochondral plugs were removed and reimplanted using a plastic tamp device fitted with a load cell. Plugs were examined at time 0 or after 48 hours or 7 days of tissue culture. During insertion, the force was 25 +/- 6 N and increased with time to a peak of 307 +/- 84 N. On average, 18 taps were necessary for the insertion of each plug, and the applied total impulse ranged from 5.7 to 17.8 N. Peak force and total impulse were highly correlated (R2 = 0.76, P < .001). Typically, a loading cycle lasted <10 milliseconds with peak loading rates up to 133 +/- 25 kN/s for each individual plug. The loading rate was dependent on the peak force, ie, the higher the applied load, the higher the rate. Cell death was 60% in the upper zone for all groups at all time points and lower (20%) for the middle and deep zones. Cell death appeared to be higher in all zones of the impacted group. Investigating the whole plug at time 0, cell viability was significantly lower for the impacted plugs compared to control (dead: P < .02, living: P = .05). After 48 hours, as well as after 7 days, mean cell viability remained affected. These data suggest that the range of loading used in the manipulation of cartilage tissue in transplantation must be carefully considered if cell preservation is to be maintained.

Prolonged-fresh preservation of intact whole canine femoral condyles for the potential use as osteochondral allografts.

Defects in articular cartilage are often repaired with fresh osteochondral grafts. While fresh allografts provide viable chondrocytes, logistic limitations require surgical implantation within seven days of graft harvest. Here, we provide information on cold preservation of whole intact osteochondral materials that retains cartilage cell viability and function, and histologic and biochemical integrity for 28 days. Canine femoral condyles were obtained and stored at 4 degrees C for 14, 21 or 28 days. At the end of the storage period, cartilage was assessed for cell viability, 35S uptake, proteoglycan content and histologic parameters. The most noticeable histologic change was reduced Safranin-O near the cartilage surface with 14 days of cold preservation, but had recovered with 21 and 28 days. Cartilage thicknesses did not vary significantly. Cell viability was >95% at 14 days, 75-98% at 21 days and reduced to 65-90% at 28 days. Cell function measures showed that the level of 35SO4 incorporation was suppressed in samples stored at 4 degrees C. However, no significant differences were seen among groups at 14, 21 or 28 days of cold preservation. This data has implications for tissue banking protocols for osteochondral allograft material obtained for transplantation suggesting that cold preserved allograft material be implanted within 28 days.