METHOD FOR SURGICAL MANAGEMENT OF CHRONIC PATELLAR INSTABILITY USING TRANSPATELLAR RECONSTRUCTION OF MEDIAL PATELLOFEMORAL LIGAMENT OF KNEE JOINT Russian patent published in 2024 - IPC A61B17/00 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to traumatology, orthopedics and neurosurgery, and can be used for surgical treatment of chronic patellar instability using transpatellar reconstruction of medial patellofemoral ligament of knee joint. In the preoperative period, spatial visualization of the involved patella is determined. Projection distance between the tibial tuberosity and the femoral block, the ratio of the distance from the lower pole of the patella to the upper point of the tibia to the length of the articular surface of the patella by Caton-Deschamps index is calculated. Presence of hip block dysplasia and osteochondral defects are determined. Degree of damage to the medial supporting ligament of the patella, trans- and osteochondral injuries of the femoral surface of the patella and external condyle of the femur, as well as the state of the surrounding soft tissues and the presence of intra-articular bodies are assessed. In the patient's back position on a radiolucent table with fixation of the knee joint position at angle of 90° anteromedial and anterolateral skin incisions 0.5–1.0 cm long are made. Arthroscopic probe is inserted through the anteromedial approach. In the anterolateral approach, 4 mm arthroscope is placed with a viewing angle of 30°, which is used to determine the degree of chondromolation of articular surfaces, as well as the presence of intra-articular bodies and cicatrical changes in the tissues of the medial supporting ligament of the patella. If observing lateral patellar hypertension, a lateral patellar retainer is released using the ablator. 4 mm arthroscope is removed from the anterolateral approach; 3.5–4.5 cm long skin is incised along an anteromedial surface of the upper third of shin. Blunt and sharp approach to the tendon of semitendinosus and gracilis muscles is performed. Tailor's fascia is dissected. Tendon of the gracilis muscle is separated. Tendon of the gracilis muscle is sampled throughout its length at the point of transition into the muscular portion. Before cutting off the tendon of the gracilis muscle from the attachment point, the tendon of the gracilis muscle is cleaned from muscle tissue. Tendon of the gracilis muscle is cut off from the attachment point. Skin is incised 4–5 cm long along the medial edge of the patella. Medial portion of the patella is approached bluntly and sharply. At distance of 1.5–2.0 cm from each other, canals are formed, converging at angle of 70° up to 90° with each other in the centre of the patella, and they are reamed to diameter of 4.5 mm. Canals are washed with normal saline. Extracted tendon of the gracilis muscle is passed through the formed patellar canals. Blumensaat line and an anatomical fixation point of the medial patella retainer are determined. Skin is incised 3–4 cm long; an anatomical fixation point of the medial patella retainer is bluntly and sharply approached. Canal is formed between the deep fascia of the hip and the joint capsule to the adduct tuberosity, and the ends of the tendon of the gracilis muscle are brought to the anatomical fixation point of the medial patellar retainer. Both ends of the gracilis muscle tendons are sutured. Anatomical fixation point of the medial patella retainer is determined, and a wire with diameter of 2.4 mm with an “eye” is delivered from the back to the front, from below upwards. Femoral canal with diameter of 6.0 mm at depth of 30 mm is formed, and the ends of the tendons of the gracilis muscle are brought, positioned and drawn, in the femoral canal by the ends of the piercing sutures. In a flexion position of knee joint 90° gracilis muscle tendon is submerged and stretched in a femoral canal, and the sutures are temporarily fixed. Position and mobility of the patella are assessed with an extended knee joint, as well as a state of tension of the tendon when the patella is attempted laterisation. Movement of the patella is assessed in the range of knee flexion from 0° up to 120°, centring the patella in the femoral block and the gracilis muscle tendon tone. Final fixation of the tendon in the femoral canal is performed with interference screw 6×20 mm from biodegradable material. Wound is washed with normal saline. Layer-by-layer closure. Aseptic dressing is applied. Pneumatic tourniquet is removed. Elastic bandaging of lower extremities. Operated extremity is fixed in orthosis HKS-303 or splint KS-601 from upper one-third of thigh to lower one-third of shin in position of knee joint extension to 180° for period of 4 weeks. In 17–19 days after surgical intervention, the patient performs passive development of movements in the knee joint. After the orthosis is removed, a course of rehabilitation treatment is carried out. Interferential screw material used is biodegradable synthetic biopolymers based on polyglycolic acid PGA or polylactic acid PLA.

EFFECT: method provides the absence of postoperative complications, reliable stabilization of the patella, reduction of operation time, elimination of probability of tendon mechanical cutting during tendon fixation in femoral canal, excluding the probability of a patellar fracture during the operation due to the use of transpatellar reconstruction of the medial patellofemoral ligament.

1 cl, 3 ex