Background Cryoablation of acetabular bone lesions risks femoral head osteonecrosis and chondrolysis due to ablation zone propagation through the joint. Traditional thermal insulation methods with gases and fluids are inadequate as they fill the joint recess around the neck. A prior case report suggested hip distraction during acetabular cryoablation can prevent femoral head osteonecrosis. This study utilized a cadaveric model to simulate cryoablation propagation and assess the effectiveness of hip joint distraction for thermal protection.

Methods A cadaver model was used to replicate hip joint distraction during acetabular cryoablation. Three conditions were compared: no intervention (control), intra-articular fluid injection, and hip distraction. The cadaver, warmed to body temperature, underwent 15 pounds of traction to create an 8mm distraction distance. A thermocouple probe placed in the femoral head recorded temperatures every minute during a 10-minute cryoablation treatment. The procedure, using a cryoprobe advanced through a coaxial needle under CT fluoroscopic guidance, simulated a previous case report.

Results Linear regression analysis showed slopes of -1.47, -1.40, and -0.33 for control, liquid, and distraction conditions, respectively. F-tests indicated significant temperature variance differences between control vs. distracted (p<0.0001) and control vs. liquid (p<0.0001), but not between liquid and distraction (p=0.45). The distraction condition maintained a more stable temperature than both the liquid-injected and control conditions.

Conclusion Osteonecrosis and chondrolysis are common complications of cryoablation due to inadequate insulation of the femoral head and acetabulum. This cadaveric study validates hip distraction as a protective method from thermal injury during cryoablation.