total knee arthroplasty in severe unstable knee: case-report and literature review

multiplanar or global laxity in arthritic knee is rare , most of this patients have neuromuscular disorder (post poliomyelitis , spinal dystrophy) or history of knee trauma. ligament insufficiency and severe bone loss is significant in this patient. the estimated prevalence for the concurrence of charcot marie-tooth (cmt) with myasthenia gravis (mg) suggests an extremely rare event. we have presented a 54-year-old female patient with cmt and mg complaining of progressive pain, swelling, and crepitation of the knee joints who had been undergone total knee arthroplasty (tka) with rotating hinge prosthesis. she had an acute myasthenia crisis soon after operation with prolonged intubation and intensive care unit admission. radiographies and physical examination revealed bilateral severe unstable arthritic knee joints and left knee posterior dislocation. short-term postoperative follow-up revealed improved knee function and resolution of all symptoms in the operated side.