Clinical outcome and quality of life of patients with periprosthetic distal femur fractures and retained total knee arthroplasty treated with polyaxial locking plates: a single-center experience.

PURPOSE: The number of total knee arthroplasties (TKA) increased rapidly. In conjunction with higher implantation rates, periprosthetic femur fractures following TKA are also gradually increasing. Purpose of this study was to evaluate polyaxial locking plate treatment of periprosthetic femoral fractures with retained total knee replacement using polyaxial locking plates in regard to quality of life, functional outcome and complications.

METHODS

The Study design is a single-center retrospective cohort analysis. Included were patients with periprosthetic supracondylar femoral fractures with a well-fixed knee prosthesis initially treated with NCB plate (Non-contact bridging plate, Zimmer Inc., Warsaw, IN). Primary outcome was measured including quality of life and functional status using the SMFA-D score (German short musculoskeletal function assessment questionnaire), the mortality rate and union rate. Formerly published SMFA-data presenting representative randomly chosen cross-sectional data from general population of the USA and Dutch population was used as historic control group.

RESULTS

In total, 45 patients with a mean age of 74 years were included (10 males; 35 females). Body mass index averaged 27.4 kg/m2. Follow-up averaged 52 months. Comparison of the SMFA-D scores showed higher scores according to bother index (41.5 vs. 15.7/13.8) and function index (42.5 vs. 14.5/12.7). Mortality rate was 26.7%. The CCI was directly related to the mortality rate (p = 0.033). Union was achieved in 35 of 45 fractures (78%) six months after the index procedure. The ultimate union rate including following procedures at last follow-up was 95.6%.

CONCLUSION

Besides already highlighted limitations in range of motion, we quantified patient-related limitations in daily living. A large number of patients after surgery are not self-reliant mobile or on orthopedic aids. A high CCI was directly related to the mortality rate and can be used as a predictive factor for postoperative mortality.