Combination of Trochleoplasty and High Tibial Osteotomy in Patellofemoral Instability Yielding Good Short-Term Results in terms of Pain Relief, Patella Stability and Knee Function

Author(s): Felix Ferner, Jörg Harrer, Christoph Lutter, Michael Wörner, Joerg Dickschas.

Introduction: In many cases patellofemoral instability (PFI) presents a multifactorial issue that often requires a combination of different surgical procedures. In addition to re-balancing relevant soft tissue structures, osseous pathologies must also be addressed. Although, the combination of trochlear dysplasia, increased external tibial torsion or valgus deformity of the knee is rare, it is usually seen in young adolescents and could thus lead to early onset patellofemoral osteoarthritis or persisting PFI. We hypothesize that the combination of trochleoplasty and high tibial osteotomy (HTO) improves patellar stability and functional scores in patients who present with trochlear dysplasia and a tibial axis deviation (valgus deformity or increased external rotation) of a lower extremity. Methods: 13 consecutive cases were included, where patients who presented with PFI were surgically treated by performing a trochleoplasty in addition to HTO. The following five inclusion criteria had to be met: (1) patients with PFI (2) trochlear dysplasia (Dejour type D), (3) tibial deformity (valgus or increased tibial torsion) of the ipsilateral limb and (4) failure of conservative treatment (5) simultaneous correction femoral and tibial. Preoperative imaging acquired consisted of conventional X-ray studies of the knee (a.p. and lateral) and full weight bearing long leg radiograph a.p. of the lower extremity, as well as a torsional CT scan of the lower extremities and a MRI of the affected knee joint. Surgical procedure consisted of trochleoplasty and HTO (tibial valgus or torsional correction) in addition to soft tissue rebalancing via lateral release. MPFL reconstruction was performed depending on patellar instability, tested intraoperatively. Subjects with previous surgical intervention, follow-up less than 6 months and femoral valgus deformity were excluded from this study. Visual analog scale (VAS), Tegner-score and the Kujala-score were compared pre- and postoperatively. Intra- and postoperative complications were registered. Results: The study group consisted of 7 male and 6 female procedures with a mean of 20.8 years of age. 6 knees received a tibial varisation osteotomy, 7 knees a high tibial torsional osteotomy, 8 knees a primary MPFL-reconstruction. No intraoperative complication occured. During a mean follow-up time of 24.2 months one patient suffered a deep vein thrombosis and consequent pulmonary embolism. One patient who did not undergo primary MPFL-reconstruction suffered a single event of patella re-dislocation, which remained stable after secondary MPFL-reconstruction. 2 patients without primary MPFL-reconstruction received MPFL-reconstruction secondary simultaneous with hardware removal due to patella subluxation after primary surgery. The Tegner score improved from 3.08 to 4.62, the Kujala score from 65.8 to 88.8, while the VAS decreased from 5.62 preoperatively to 1.77 postoperatively. Conclusions: This multi-case study shows that the combined surgical procedure consisting of trochleoplasty and HTO improves patellofemoral stability and knee function while provoking a low rate of intra- and postoperative complications. The rare number of individuals suffering from PFI due to trochlear dysplasia and tibial valgus or increased external rotation deformity can be safely treated in a single surgical setting yielding good clinical results in terms of pain relief, functional scores, and patellar stability, while primary MPFL-reconstruction yields a better patella stability.