Abstract
Introduction
Deformity influences the weight bearing stresses on the knee joint. Correction of mechanical alignment is performed to offload the knee and slow the rate of degenerative change. Fixator assisted deformity correction facilitates accurate correction prior to internal fixation. We present our results with standard Ilizarov and UNYCO system assisted deformity correction of the lower limb.
Materials and Methods
Retrospective analysis of adult surgical cases of mechanical re-alignment performed between 2010 and 2019 in a tertiary referral centre. We recorded standard demographics and operative time from the electronic patient record. We analysed digitalised radiographs to record pre- and post-operative measurements of: Mechanical axis deviation (MAD), femoral tibial angle (FTA), Medial Proximal tibial angle (MPTA) and Mechanical lateral distal femoral angle (mLDFA). The accuracy of the correction was analysed. Time to healing, secondary interventions and complications were also recorded.
Results
7 patients underwent fixator assisted deformity correction with the UNYCO system and 11 with a standard Ilizarov frame. Mean pre-op MAD was 45.8mm in the UNYCO group and 43.4mm in Ilazrov; Mean post-op MAD was 9.5mm in the UNYCO group (5–15) and 12.3 in the Ilizarov group (1–25) p=0.07. The average surgical time in the UNYCO group was 200 minutes (128–325) and 252 minutes (203–301) in the Ilizarov group p=0.07.
The mean post op MPTA was 90.2 (87–96) in the UNYCO group and 87.4 (81–94) in the Ilizarov group. The mean mLDFA was 90.0(81–93.5) in the UNYCO group and 87.3(82.2–93.9) in the Ilizarov group.
All the corrections involved a plate or nail fixation and mean time to union was 76.3 days in the UNYCO and 117.3 in the Ilizarov group.
Conclusions
Both systems allowed accurate correction of deformity and limb alignment. In this small series we were unable to show a difference in theatre time. The application of the principles of deformity correction are as important as the surgical methods.
