Tibia stress fractures in patients with severe knee osteoarthritis managed with total knee arthroplasty with long stem tibia component: a case series

Introduction: Stress fractures in tibia is not a common finding in patients with knee osteoarthritis (OA). It is mostly seen in advanced disease with a significant varus deformity. The purpose of this case series is to bring forth the advantages of using stemmed knee replacement implants for treating this condition and to highlight the factors contributing to stress fractures in patients with severe knee arthritis. Case Series: 4 patients with grade 4 Kallegren and Lawrence osteoarthritis, all obese, with >20 degree varus deformity, presented with sudden increase in pain around knee joint, with point tenderness in proximal tibia. Diagnosis was confirmed as proximal tibia stress fractures radiologically. All patients were managed by total knee replacement with stemmed tibial prosthesis. 2 patients had posterior stabilized system and 2 had constrained implants. Early mobilization was done in the post-operative period with gradual weight bearing over 2-3 weeks. No complications were noted and fracture united in all by 2 months. Rehabilitation of all the patients was satisfactory and at 6 months follow-up knee society score was comparable to standard knee replacement. Discussion: Although such stress fractures show good union with conservative management, but knee immobilization may aggravate the symptoms of knee osteoarthritis .This case series show stemmed implants as an effective way of simultaneously treating the fracture and osteoarthritis of knee and provide early and quick rehabilitation. Severe osteoarthritis of knee with varus deformity pose a threat for stress fracture development and knee replacement should be considered as an option to prevent stress fractures in severely deformed osteoarthritic knees.