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Late presentation of osteoarthritic patients led to the evolution of the problem of complex knee deformities. These are cases of bi or multi-planar deformities with associated stiff or loose knees. Associated deformities can be flexion, recurvatum, internal or external tibial torsion. The commonest combination was varus, flexion and internal tibial torsion with deformities mostly intra-articular.
So simultaneous correction of these deformities was found to be challenging where restoring limb alignment, gap balancing while obtaining adequate range of motion had to encounter many problems.
Measured resection technique with balancing the extension gap first showed excellent results, resecting less bone and preserving bone stock for further revisions.
Throughout this study many controversies were tried to be solved through applying cutting edge techniques despite the scarcity of equipment.
Old concepts as regarding the subvastal approach were changed as this approach showed to be applicable in obese patients with severe deformities with excellent results as regarding early rehabilitation and achieving target range of motion.
Pre-operative planning, adequate bone resection and sequential release of medial structures yielded adequate gap balancing in flexion and extension.
In patients having a mismatch in the medial and lateral gaps in flexion, extension, or both of > 2 mm after releases, which were un-correctable with the use of a standard Posterior stabilized (PS) insert, CCK inserts were used.
Full extension was achieved in most of cases of flexion deformities through increasing distal femoral cuts, increasing femoral component size and, posterior capsular release and osteophytectomy.
Bone defects were managed adequately by either lateralizing and under-sizing tibial components, bone grafts or metal augments with excellent results and no signs of loosening or radiolucent lines. Stems were used to protect this reconstruction.
The present study included 41 patients with 45 knees (through a period from February 2015 to March 2018) with primary varus osteoarthritis with a preoperative anatomic tibio- femoral angle more than 5º varus on weight-bearing coronal radiographs with a mean preoperative anatomic tibio-femoral angle of 12.4º (range from 5º to 40º).
There were 36 females and 5 males with a mean age at the time of surgery of 60 years old (range from 55 to 73 years), 15 patients had the right knee replaced, 22 patients had the left one, while 4 patients had bilateral total knee replacement all of them were done staged.
The prostheses used in this study were cemented Fixed bearing posterior stabilized (PS) in 44 knees, 2 of which were gender-specific and mobile bearing PS in 1 knee.
Tibial stem was used in 13 cases and CCK insert was used in 13 cases.
The present study showed the benefit from total knee arthroplasty for the treatment of complex osteoarthritic varus knee deformities with an increase in the knee society score from 12.8 preoperatively to 91.5 postoperatively and improvement of the functional knee score from 36 preoperatively to 82 postoperatively.
Strictly applying infection control measures and peri-operative medications prevented the occurrence of post-operative complications e.g. infection or thromboembolism in all cases of this study.
Recent guidelines for deformity correction during total knee replacement showed excellent to good results in all cases of this study, yet longer studies with larger numbers are needed to rule out the occurrence of loosening or any other complications.