Isolated MPTL reconstruction fails to restore lateral patellar stability when compared to MPFL reconstruction

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA sports traumatology, arthroscopy : official journal of the ESSKA, 2021-03, Vol.29 (3), p.793-799
• Main Authors: Ambra, Luiz Felipe, Franciozi, Carlos Eduardo, Phan, Amy, Faloppa, Flavio, Gomoll, Andreas H.
• Format: Article
• Language: English
• Subjects: Biomechanical Phenomena; Biomechanics; Cadaver; Cadavers; Cartilage; Constraints; Contact pressure; Dysplasia; Evaluation; Female; Femur; Femur - surgery; Gracilis Muscle - surgery; Humans; Joint Instability - surgery; Knee; Knee Joint - surgery; Lateral displacement; Lateral stability; Lesions; Ligaments; Ligaments, Articular - physiopathology; Ligaments, Articular - surgery; Magnetic resonance imaging; Male; Medicine; Medicine & Public Health; Middle Aged; Orthopedics; Patella - physiopathology; Patella - surgery; Patellar Dislocation - surgery; Patellar Ligament - surgery; Patellofemoral Joint - physiopathology; Patellofemoral Joint - surgery; Quadriceps muscle; Quadriceps Muscle - surgery; Radiographs; Radiography; Range of Motion, Articular; Reconstruction; Reconstructive Surgical Procedures - methods; Stability analysis; Tendon Transfer; Tendons - surgery; Test equipment; Translation
• ISSN: 0942-2056; 1433-7347
• DOI: 10.1007/s00167-020-06015-3

Purpose To biomechanically evaluate MPTL reconstruction and compare it with two techniques for MPFL reconstruction in regard to changes in patellofemoral contact pressures and restoration of patellar stability. Methods This is an experimental laboratory study in eight human cadaveric knees. None had patellofemoral cartilage lesions or trochlear dysplasia as evaluated by conventional radiographs and MRI examinations. The specimens were secured in a testing apparatus, and the quadriceps was tensioned in line with the femoral shaft. Contact pressures were measured using the TekScan sensor at 30°, 60° and 90°. The sensor was placed in the patellofemoral joint through a proximal approach between femoral shaft and quadriceps tendon to not violate the medial and lateral patellofemoral complex. TekScan data were analysed to determine mean contact pressures on the medial and lateral patellar facets. Patellar lateral displacement was evaluated with the knee positioned at 30° of flexion and 9 N of quadriceps load, then a lateral force of 22 N was applied. The same protocol was used for each condition: native, medial patellofemoral complex lesion, medial patellofemoral ligament reconstruction (MPFL-R) using gracilis tendon, MPFL-R using quadriceps tendon transfer, and medial patellotibial ligament reconstruction (MPTL-R) using patellar tendon transfer. Results No statistical differences were found for mean and peak contact pressures, medial or lateral, among all three techniques. However, while both techniques of MPFL-R were able to restore the medial restraint, MPTL-R failed to restore resistance to lateral patellar translation to the native state (mean lateralization of the patella [mm]: native: 9.4; lesion: 22; gracilis MPFL-R: 8.1; quadriceps MPFL-R: 11.3; MPTL-R: 23.4 ( p