Abstract
The purpose of this study is to analyze the clinical results after treatment of patellofemoral
instability and maltracking caused by torsional or axial deformities of the lower
extremity by combined distal femoral osteotomies (DFOs). We analyzed 31 DFOs (25 patients)
with patellar maltracking and instability, treated in our clinic. Torsional angles
and the leg axis in the frontal plane were measured preoperatively. Standardized scoring
systems were determined pre- and postoperatively including a clinical examination.
Nineteen cases of torsional and 12 cases of axis deformities were evaluated 27 (12–64)
months postoperatively. Among those with torsional deformity, mean femoral torsion
was –39.0 ± 8.8 degrees, tibial tuberosity to trochlear groove (TT-TG) 20.3 ± 4.5
mm. We performed 19 torsional (+11.4 ± 2.4 degrees) DFOs with medial patellofemoral
ligament (MPFL) augmentation (n = 19), tibial tuberosity transfer (n = 14, 10.9 ± 6.0 mm), varus (n = 4, 3.3 ± 1.0 degrees), or valgus (n = 1, 7.0 degrees) correction. Among valgus deformities, the leg axis was 6.7 ± 2.3
degrees valgus and TT-TG 19.3 ± 5.0 mm. We performed 12 medially closing-wedge DFOs
(7.6 ± 2.8 degrees) with MPFL augmentation (n = 12) and tibial tubercle transfer (n = 9, 11.4 ± 7.3 mm). Visual analogue pain scale improved from 6.2 to 1.5 (p = 0.000), Kujala score from 45.0 to 81.5 (p = 0.000), Lysholm score from 40.3 to 83.9 (p = 0.000), and Tegner score from 2.1 to 3.9 (p = 0.000). Preoperative cartilage damage significantly influences the postoperative
functional outcome (Lysholm score) (p = 0.026) as well as the improvement in terms of the Kujala score (p = 0.045) in the overall collective. No redislocation was observed. Patellofemoral
maltracking and instability in torsional and axis deformities can successfully be
treated by combined DFOs with excellent clinical results. The coexistence of risk
factors for patellar instability requires a combination of additional procedures to
complement the osteotomy. Preoperative cartilage lesions significantly influence the
clinical outcome.
Keywords
patella - torsional deformity - osteotomy - maltracking - instability