Double-level torsional osteotomy a treatment for the 'inwardly pointing knee' syndrome

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.

Keywords: Anterior knee pain; Double level osteotomy; Inwardly pointing knee; Patellar dislocation; Patellofemoral instability; Torsional osteotomy.

Fig. 1

Clinical photographs: Prone position measurement in the clinical examination. The raised femoral internal rotational is obvious

Fig. 2

Torsion angle CT scan of a 19 year-old female patient with severe ‘inwardly pointing knee syndrome’. The woman suffered from anterior knee pain and patellar dislocation

Fig. 3

Axial view: Intraoperative pictures performing a tibial internal osteotomy via lateral approach. The two positioned Schanz screws–one proximal and one distal to the osteotomy level—are used as torsional indicators to execute the torsional correction. After correction both Schanz screws are congruent on the axial view

Fig. 4

Intraoperative picture performing a double-level osteotomy. Here the tibial internal osteotomy is done via lateral approach. The two Schanz screws have been positioned–one proximal and one distal to the osteotomy level. They are used as torsional indicators to execute the torsional correction. In this step the K-wire is placed to mark the level for the osteotomy

Fig. 5

Intraoperative x-ray lateral view after the tibial internal torsional osteotomy as the first step of a double-level torsional osteotomy. The osteotomy was performed and osteosynthesis was done with a 5-hole DCP plate tibial. In the lateral view the infratuberositary level of the osteotomy leading to a supratuberositary level at the ventral aspect can be seen

Fig. 6

Axial view: Intraoperative picture performing the femoral external torsional osteotomy as second step of a double-level torsional osteotomy. Positioning of the two Schanz screws for the torsional measurement. The two screws were set in the exact torsional angle of correction which should be achieved. This was measured with a sterile angle gauge reed in axial view of the leg

Fig. 7

Intraoperative torsional measurement with two Schanz screws as torsional indicators performing a femoral external rotational osteotomy, medial approach

Fig. 8

Intraoperative picture performing the femoral external torsional osteotomy as second step of a double-level torsional osteotomy. The supracondylar osteotomy has been performed and as the two Schanz screws standing in parallel position indicate the torsional correction has been achieved. The MDF TomoFix plate is being insert

Fig. 9

Radiography of the knee in two planes of a 21 year-old woman with severe ‘inwardly pointing knee syndrome’ six months after double-level (12°-femoral external and 12°-tibial internal rotational) osteotomy and osteosynthesis (with 5-hole DCP plate tibial and MDF TomoFix femoral), bony consolidation

Fig. 10

Post-operative x-rays long leg view of a 17 year-old female 10 months after double level osteotomy (femoral external and tibial internal rotational osteotomy) and osteosynthesis, bony consolidation

Fig. 11

Anonymized list of all included patients with detailed information on age, gender, weight, height, operated side, surgery, implants, previous surgery, additional procedures, results of clinical examination, diagnoses and indication, symptoms (including number of patellar dislocations), follow-up period and findings in imaging

Fig. 11

Anonymized list of all included patients with detailed information on age, gender, weight, height, operated side, surgery, implants, previous surgery, additional procedures, results of clinical examination, diagnoses and indication, symptoms (including number of patellar dislocations), follow-up period and findings in imaging

Fig. 12

The table shows the outcome (in percentage) for the 18 patients in the clinical scores: VAS, Lysholm, Kujala, Tegner activity score, Japanese knee score and if they are willing to do the procedure again. For the scores the standard deviation is shown

Fig. 13

Diagnostic algorithm for ‘inwardly pointing knee’ syndrome