High tibial osteotomy with a dynamic axial fixator
PRECISION IN ACHIEVING ALIGNMENT
V. Bachhal, MBBS, MSOrtho, DNBOrtho, Registrar in Orthopaedics1; S. S. Sankhala, MBBS, MSOrtho, Professor of Orthopaedics2; N. Jindal, MBBS, Orthopaedic Resident2; and M. S. Dhillon, MBBS, MSOrtho, MNAMS, Professor Head of Orthopaedics1
1 Postgraduate Institute of Medical Education & Research, Sector-12, Chandigarh 160012, India.
2 Sawai Man Singh Medical College & Hospital, Sawai Ramsingh Road, Jaipur 302004, Rajasthan, India.
Journal of Bone and Joint Surgery – British Volume, Vol 93-B, Issue 7, 897-903. doi: 10.1302/0301-620X.93B7.26124
- The authors reported outcome on 32 patients(37knees) who underwent hemicallostasis with a dynamic external fixator for osteoarthritis of the medial compartment of the knee.
- mean age at operationof 54.6 years.
- The aim was to achieve a valgus overcorrectionof 2° to 8° or mechanical axis at 62.5% (± 12.5%).
- At a mean follow-up of 62.8 months the authors found that there was no changein the mean range of movement, and no statistically significantdifference in the Insall-Salvati index or tibial slope (p =0.11 and p = 0.15, respectively).
- The mean hip-knee-ankle angle changed from 190.6 (183° to 197°) to 176.0° (171°to 181°), with a mean final position of the mechanical axisof 58.5% (35.1% to 71.2%).
- The desired alignment was attained in 31 of 37 (84%) knees.
- The authors reported excellent results in 21 patients, 13 good results, two fair and one poor result according to the Oxford knee score with no correlation betweenage and final score.
- This score was at its best at one year with a statistically significant deterioration at two years(p = 0.001) followed by a small but not statistically significant deterioration until the final follow-up (p = 0.17).
- In Ahlback grade 1 osteoarthritis patients the results were excellent or good
- Complications included pin tract infections involving16.4% of all pins used, delayed union in two, knee stiffness in four, fracture of the lateral cortex in one and ring sequestrum in one.
- The authors reported that hemicallostasis provides precision in attaining the desired alignment without interfering with tibial slope or patellar height, and is relatively free of serious complications.