Double-level torsional osteotomy a treatment for the ‘inwardly pointing knee’ syndrome
Authors: Liße Jens , Perl Mario , Dickschas Jörg 
Published: May 2022

Abstract
Introduction
A ‘inwardly pointing knee’ syndrome is a combined torsional deformity with increased femoral internal and tibial external torsion. After clinical and radiological verification of the torsional deformity and unsuccessful conservative therapy approach, a combined (double level) torsional osteotomy of femur and tibia might be the appropriate treatment. Here, we present the diagnostic algorithms, treatment, and outcome of combined torsional osteotomies of femur and tibia. The aim of the study is to show that patients treated with the procedure achieve patellofemoral stability and pain relief or reduction.

Material and methods
Twenty torsional osteotomies performed on 18 patients were included. Nine patients had experienced patellar dislocation in 11 joints before. All patients were suffering from anterior knee pain. All patients underwent a clinical and radiographical evaluation, including a torsion angle CT scan. Pre- and post-operatively multiple commonly approved scores (Lysholm Score, Tegner Activity score, Kujala Score, VAS and Japanese Knee Society score) were acquired.

Results
In 18 patients we performed 20 double-level torsional osteotomies. 9 patients suffered from patellar dislocations in 11 knee joints prior to surgery. All patients were suffering from anterior knee pain. Of these 7 patients achieved a stable joint after surgery without further patellar dislocations. All achieved more knee stability and experienced less patellar luxation then before surgery. The mean duration of follow-up was 59 months (range 9–173 months).
The mean VAS was significantly reduced by 3.75 points (SD 2.09, p value 0.0002) from 5.50 points (SD 2.73, range 0–9) before surgery to 1.75 points (SD 1.67, range 0–5) after surgery. The Lysholm score increased significantly by mean of 27.6 (SD 17.55, p value 0.0001) from mean 62.45 (SD 22.71, range 22–100) before surgery to mean 90.05 (SD 10.18, range 66–100) after surgery. The Kujala Score did improve significantly in average by 25.20 points (SD 13.61, p value 0.00012) from mean 62.9 (SD 16.24, range 35–95) to mean 93.2 (SD 9.20, range 66–100). The Tegner activity score did increase significantly by 1.2 points (SD 1.47, p value 0.004) in average from mean 2.65 (SD 1.11, range 1–5) to mean 3.85 (SD 1.42, range 1–6). The Japanese knee score did increase significantly by 19.15 in average (SD 11.95, p value 0.0001) from mean 74.05 (SD 14.63, range 33–95) to mean 93.05 (SD 10.18, range 68–100).

Conclusion
This is the first publication reporting about simultaneous double-level torsional osteotomies in a comparatively high number of patients. In addition, this is the first publication assessing the patient collective afterwards with objectifying clinical outcome scores. The results show that double-level torsional osteotomy is an effective treatment for patients with patellar dislocation or subluxation associated to torsional deformities of femur and tibia. Furthermore, we introduce a diagnostic algorithm for ‘inwardly pointing knee’ syndrome.

Level of evidence
Level IV.