Lykhodii V. Diagnostic and treatment of patellar instability

The dissertation is devoted to the orthopedics' actual issue: the improvement of treatment results of patients with patellar instability by devising a system of diagnostics, prevention and the pathogenetic well-grounded restorative management. The poor results are related to the development of the anterior knee pain in 22.6 % of cases, and the failure of reefing of medial patellofemorall ligament that result in a subjective instability in 15.1% and recurrence of patellar dislocation in 1.8% of cases. The trochlea dysplasia, the soft tissue patellar stabilizers onto patellar stability and distribution of tension in patellar cartilage have been investigated experimentally. The tension in the patellar cartilage increases at patellar instability. Relatively greater stress is in the cartilage at the patella instability with dysplasia type B than with dysplasia type A. Using computer modeling, MRI, dynamic MRI determined that patellar stability in case of trochlea dysplasia type B is more dependent on the condition of the medial patellofemoral ligament and lateral retinaculum than with trochlea dysplasia type A. Lateral release reduces some tension in patellar cartilage, changes the area of stress distribution; moreover it facilitates the patellar lateralization. The diagnostic value of clinical tests and ultrasonographic criterion to define the patellar instability has been identified. The proposed ulrasonographic criterion of patellar instability detects failure of medial patellofemoral ligament. The severity of the patellar cartilage damage depends on the type of trochlea dysplasia (рА-В=0,033) and duration of disease (р=0,002). They have demonstrated that types of trochlea dysplasia and the kind of operation have an influence on the treatment outcomes. Reconstruction of medial patellofemoral ligament is necessary in case of patellar instability with trochlea dysplasia type B, whereas in type A dysplasia it is possible to apply the medial patellofemoral ligament suture in patients with a single dislocation and monofocal injury of the patellofemoral ligament at the patella origin. The necessity for lateral release is solved intraoperatively.