The influence of tensometric evaluation of the pain threshold on the nature of resistance exercising in disorders of the knee joint.

Background. We evaluated the usefulness of tensometric examination of the quadriceps as a means of assessing the pain threshold for the subcartilage layer in the patellofemoral joint and the knee joint. Material and methods. Our study, carried out from 2000 to 2003, included 131 patients, 77 men and 54 women, age 12-52. The examination results were compared with those for the unaffected leg. After each examination a new level of exercise workload was established, always just below the pain threshold. Examinations were repeated after one, three and six months. Results. The level of the pain threshold in most cases excluded workloads involving flexion of the knee at 90 degrees , 45 degrees , and 0 degrees . Training with a load adapted to the pain threshold served as endurance training, and should be regarded as a way to harden the cartilage. When the exercise load was adjusted in accordance with tensometric examination results, cartilage resistance to pressure increased. This kind of training allows the patient to achieve painlessly 80-90% strength in the quadriceps (compared to the healthy leg) in 6-12 months. Conclusions. Tensometric examination of the knee is a useful instrument in the evaluation of sensitivity to pain in the subcartilage layer, enabling the evaluation of the range of pressure that does not induce subcartilage pain when the joint is under load by working muscles. Properly selected workloads have a favorable impact on resistance to pressure and cause a virtually complete restoration of quadriceps strength after 6-12 months of rehabilitation.