The Design Of A Novel Progressive Stretch Device For Stiff Knee And Animal Experiments

Stiff knee can occur following knee surgery, trauma, or immobilization. This can severely impact gait, mobility, function, and overall quality of life. The reported prevalence of knee contractures after total knee arthroplasty varies due to differing diagnostic criteria, and has ranged from 1.3% to 15%. It is usually treated successfully with mobilization, stretching, strengthening, and gait training. However, stiffness and pain can persist despite these therapeutic modalities and can cause severe dysfunction.When functional problems caused by knee stiffness continue despite aggressive physical therapy, various other nonoperative techniques can be utilized in an attempt to improve symptoms, including various orthoses and serial casting,and it involves multiple visits and may cause skin as well as damage. Operative treatments for knee stiffness include manipulation under anesthesia, lysis of adhesions and/or soft tissue release, external fixators, as well as revision arthroplasty. These procedures have success rates ranging from 66% to 94%. Despite the success rates of some surgical treatments for knee stiffness, nonsurgical options should be attempted prior to considering these more invasive procedures. This may reduce complications, decrease costs, and increase patient satisfaction.Objective To build up an animal model , similar to human ankylosed extensor knee.And then to develop a novel progressive stretch device(PSD) for stiff knee, and explore the efficacy of the animal experiments.Methods (1)Bore holesin the goat knee femoral cartilage surface with Kirschner wire,damaged the anterior bone surface of femoral metaphys and overlapping suture patellar ligament.Then the knee joint was fixed in continuous extension with Kirschner wire and plaster cast. Remove fixation postoperative 8 weeks. Range of motion of knee joint activation were measured after postoperative 8 weeks and postoperative 12 weeks respectively.(2) Three adult left stiff knee goats used the PSD gradually pulling the left stiff knee three weeks.Then removal the PSD. To record the left knee maximum flexion degrees of preoperation, the day of removaling the PSD and a week after removaling the PSD, r espectively.Results (1)Whether in the postoperative 8 weeks or postoperative 12 weeks,the extent of ankylosed extensor of operational knee was severe than the contralateral knee.And compared between postoperative 8 weeks or postoperative 12 weeks, the extentof ankylosed extensor of operational knee degree has no significant loss.(2) After three weeks of treatment with PSD, the left knee maximum flexion degrees were significantly improved than preoperation(p < 0.01), with a mean correction of 103°. A week after removaling the PSD, no significant loss of the left knee maximum flexion degrees.Conclusion Merger cartilage destruction, overlapping suture patellar ligament and fixation at extension knee mustexercises can cause Goat knee joint serious and long-lasting ankylosed extensor.And PSD has a good effect on treatment of goat model with stiff knee. And PSD has the possibility of clinical application.