Less invasive polyaxial locking plate fixation in periprosthetic and peri-implant fractures of the femur--a prospective study of 41 patients.

BACKGROUND: A great variety of methods for the stabilisation of periprosthetic fractures around total hip (THA) or total knee arthroplasty (TKA) have been described. We present the data of our experience in combining a polyaxial, anatomical locking plate with a standardised less invasive technique in the treatment of periprosthetic and peri-implant (femoral nail) femur fractures in this prospective study.

PATIENTS AND METHODS: A consecutive series of 41 patients (33 women; age 79.8±11 years) with 41 fractures (n=17 periprosthetic THA, n=10 periprosthetic TKA, n=3 interprosthetic, n=11 perinail) was treated in a 'mini-open' (MO; direct reduction of the fracture and percutaneous plate fixation in two-part fractures; n=22) or a 'minimally invasive' (MI; indirect reduction and percutaneous fixation; n=19) technique. All patients were followed up for 12 months postoperatively.

RESULTS: The polyaxial locking mechanism allowed for the setting of a mean of 5.3 screws around an intramedullary implant. Supported by the less invasive strategy, mainly long plates (n=36; 88% were longer than 24cm) were applied without relevant soft-tissue complication. Five surgical revisions (12.1%) had to be performed. During the first postoperative stay, one seroma was evacuated and in two cases the plate broke due to failed biological healing 6 months after the MO technique. In one case, a revision prosthesis had to be implanted due to ligamentous instability, and in another case, soft-tissue balancing of the patella was performed. In the MO group, four of the five complications requiring surgical revision were seen. There was no infection. No statistical difference was seen between the MO and the MI groups for operating room (OR) time and perioperative need for transfusion. In patients with a poor state of health (n=8; immobile and Glasgow Coma Outcome Scale=3), no local complications were seen. All fractures in the peri-implant fracture group (n=11) healed uneventfully.

CONCLUSION: Periprosthetic fracture fixation can be performed as part of a standardised less invasive strategy, but the MI technique should be the preferred treatment. The NCB(®) system allows for a stable plate fixation around an intramedullary implant. With the less invasive technique, long plates can be applied with low rates of soft-tissue complication and implant failure.