Does Patella Tendon Tenodesis Improve Tibial Tubercle Distalization in Treating Patella Alta? A Computational Study

Abstract

Background Patellofemoral malalignment associated with patella alta may cause pain and arthritis; because of this, the condition sometimes is treated surgically. Two common procedures are tibial tubercle distalization with or without patellar tendon tenodesis. However, the biomechanical consequences of these interventions for patella alta are not clearly understood. Questions/purposes We evaluated changes in patellofemoral joint contact mechanics after tibial tubercle distalization and tibial tubercle distalization combined with patella tendon tenodesis. Specifically, we asked: (1) Are there biomechanical differences between these two types of procedures? (2) Is there an ideal range to distalize the patella? Methods Subject-specific finite-element models were created for 10 individuals with patella alta (mean InsallSalvati ratio of 1.34 ± 0.05). Input parameters for the finite-element models included subject-specific joint geometry, quadriceps muscle forces, and weightbearing patellofemoral joint kinematics. Virtual operations were conducted to simulate the two procedures. For distalization, the tibial tubercle and patella were displaced distally 4 mm to 20 mm in 4-mm increments based on the original model. At each level of distalization, the patella tendon was attached back to its original insertion to simulate the additional tenodesis procedure. Cartilage stress, contact area, and contact forces were quantified and compared between procedures and distalization levels. Results Distalization and distalization + tenodesis reduced patellofemoral joint stress compared with the baseline of 1.02 ± 0.11 MPa. Distalization led to lower cartilage stress than distalization + tenodesis, and the effect size was relatively large (0.88 ± 0. Conclusions Cartilage stress appears lower using distalization as opposed to distalization + tenodesis in this finite-element analysis simulation. An Insall-Salvati ratio of 0.95 may be an ideal level for distalization; further distalization does not show additional benefits. Clinical Relevance This study suggests that distalization may result in less stress than distalization + tenodesis,

Patella height influences patellofemoral contact and kinematics following cruciate‐retaining total knee replacement

“…The ligament parameters are summarized in the Supporting Information: Table and were adapted from previous studies 36,38–40 . Due to the high stiffness, the PL was modeled as a rigid coupling between apex patellae and tuberositas tibiae, 23,30,41 and its length is dependent on the respective patellar height 23,42,43 …”

“… Exemplary measurement of the patella height with the Blackburne‐Peel (BP) ratio in the case of the posterior cruciate‐retaining total knee replacement, according to the description from previous studies 39,42,54,55 . Parameter a is the length of the articulating retropatellar surface.…”

“…In this manner, we generated the following BP indices: baja (0.39, 0.49), normal patella height (0.65, 0.75, 0.85), and patella alta (1.01 and 1.1) (Figure 2). 54 After placing the patella at different heights, the length of the patellar tendon between tuberositas tibiae and patella apex was measured, thus resulting in a shortened or lengthened patella tendon, respectively 23,42,43 . The BP ratio was reevaluated after each parameter configuration.…”

Corrección de La Altura Patelar En Inestabilidad Rotuliana

“…10,51 Estudios clínicos han demostrado que ambos procedimientos (►Figuras 5C y 5D) disminuyen la altura patelar, reducen la probabilidad de luxación patelofemoral y mejoran los resultados en las encuestas de satisfacción reportadas por pacientes. 43,51 Recientemente, un estudio biomecánico 52 evaluó el contacto patelofemoral tras realizar ambos procedimientos en condiciones controladas de transferencia distal, encontrando que aquel que solo realiza la osteotomía genera menor estrés en el cartílago, además de necesitar menor distancia de desplazamiento para alcanzar ese objetivo.…”

Tibia Tubercle Distalization Osteotomy: A Surgical Technique

“…Patellar tendon tenodesis procedures in conjunction with tibial tubercle distalization osteotomies have also been described, specifically in patients with abnormally long patellar tendons ( > 52 mm). [15][16][17] Mayer and colleagues described their technique by placing 2 suture anchors near the top of the original location of tubercle before bone fixation. After fixation, the one suture from each anchor is passed around either side of the tendon and then tied…”