Femoral component fracture is a rarely reported but devastating complication of total knee arthroplasty. It has occurred most frequently with Whiteside Ortholoc II replacements uncemented knee replacements. Presentation may be with acute pain, progressive pain or returning deformity. It occurs more commonly in the medial condyle of the femoral component. It is rarely seen in cemented replacements. All currently available literature describing fractures of condylar replacements, both cemented and uncemented. Predisposing factors include varus deformity either pre or post operatively. The mechanism of failure is thought to be failure of the infiltration of bone into the replacement. This is often due to polyethylene wear or metallosis causing abnormal tissue reaction with or without osteolysis. We present the case of a fractured Press Fit Condylar (PFC) cemented implant (DePuy, Johnson&Johnson, Raynham, Massachusettes, USA) affecting the medial condyle. To our knowledge this is only the third reported case of fracture in a PFC implant, and the first in a cemented PFC implant. Our patient was a 64 year old male who presented with unresolving knee pain post total knee arthroplasty, caused by fatigue fracture of the medial condyle of the femoral component. This was identified as loosening on plain radiographs and replaced with a revision prosthesis with a good post operative result. Given our aging population and with the increase of joint arthroplasty, this case sheds light on a potentially under recognised and increasingly important cause of knee pain following arthroplasty.
All patients were evaluated prior to surgery. The patients with coexisting inflammatory disease or peri-prosthetic fracture were also evaluated. A hip was diagnosed as infected on the basis of positive intra operative microbiology samples three or more out of five and or histological evidence.
14 patients had an underlying inflammatory arthritis and 5 were peri prosthetic fractures. The inflammatory markers tended to be elevated in these patients. Excluding these 19 patients and using the same criteria, the positive predictive value was 65% and the negative predictive value was 97%
After 18 months of successful surgery she presented with short duration (2 weeks) history of thigh swelling with pain and stiffness in hip and knee. Clinically gross circumferential swelling of right thigh from inguinal ligament to the knee joint. She had increased serum cobalt chromium levels. Aspiration of hip revealed high levels of cobalt and chromium. Biopsy and intra operative samples at revision revealed “no infection or tumor but non specific inflammatory reaction.” The patient underwent revision surgery to ceramic-plastic bearing.(THR). 12 months post operative, the swelling has reduced with painless mobile hip and knee joints.
Pre operative diagnosis was Osteoarthritis (n=135), osteonecrosis(n=8),traumatic(n=2),dysplasia(n=3),Slipped capital femoral epiphysis (n=1) and ankylosing spondylitis (n=1). Al hips were implanted via the posterior approach. Clinical assessment, by postal questionnaire, was by pre and post-operative Oxford Hip scores (OHS) and X-rays were reviewed.
There was one dislocation in a neuropathic hip requiring bracing. (OHS 29). There was one retained alignment pin needing removal. Otherwise patients were highly satisfied with the operation with excellent function and Hip scores.