Complications of implant removal after healed hip fractures

Osteosynthesis of pertrochanteric fractures is one of the most frequently performed procedures in orthopaedic trauma care. Auto-dynamization during fracture healing can lead to lateralization of the screw or blade. This can cause debilitating complaints, which sometimes necessitate the removal of the screw or blade. After removal of the implant, we observed spontaneous femoral neck fractures in five patients. This article presents an evaluation of these cases with reference to literature.

Five cases of spontaneous femoral neck fracture (SFNF) after cephalomedullary nail removal are described. A literature search was performed on the incidence of chronic pain and gait impairment associated with auto-dynamization, and on risk factors for dynamization and complications after implant removal. Based on these findings recommendations are made for the prevention of SFNF.

Over a 2-year period, we observed five cases of SFNF after cephalomedullary nail removal. In literature, reduced mobility, gait impairment and chronic pain are associated with screw or blade dynamization. Pertrochanteric fractures with AO-type 2 classification were associated with more dynamization and screw lateralization and henceforth more trochanteric pain and gait disturbances. SFNF after cephalomedullary nail removal occurs with an incidence of at least 15%, affecting mostly elderly patients. This severe complication mostly occurs within 3 weeks after implant removal. Risk factors associated with SFNF are pre-existing systemic osteoporosis, stress-shielding, pre-loading of the implant and nail removal of the cephalomedullary implant.

The clinical indications for implant removal in healed pertrochanteric fractures are not well established and should be restricted to specific cases. After removal of these implants without replacement partial weight-bearing should be advised strictly. Based on our findings it is recommended to replace the cephalomedullary nail with a shorter one, ideally combined with implant augmentation.