Effectiveness of one-stage total knee arthroplasty with tibial stem extender for knee arthritis complicated with tibial stress fracture

Abstract

To evaluate the early effectiveness of one-stage total knee arthroplasty (TKA) with tibial stem extender for knee arthritis complicated with tibial stress fractures. Between January 2014 and November 2016, 12 patients (12 knees) with knee arthritis and tibial stress fractures underwent one-stage TKA with tibial stem extender. There were 5 males and 7 females with an average age of 71.5 years (range, 60-77 years). There were 8 cases with osteoarthritis and 4 cases with rheumatoid arthritis. The radiographic examination showed the 6 cases of intra-articular fractures and 6 of extra-articular fractures (including transverse fractures in 4 cases and short oblique fractures in 2 cases); 2 cases complicated with middle and upper fibular stress fractures; all patients of varus deformities. Preoperative Knee Society Score (KSS) clinical score was 31.5±8.4 and functional score was 33.3±9.0. The preoperative range of motion (ROM) of the knee was (65.6±9.6)°. All indexes healed primarily and no wound infection or skin necrosis occurred. All patients were followed up 36.5 months on average (range, 6-52 months). X-ray films showed that all fractures healed at 3-7 months (mean, 4 months); the position of the prosthesis was good, and no loosening or signs of infection occurred. At last follow-up, the KSS clinical score was 90.5±8.9 and functional score was 92.1±7.8; the ROM of the knee was (115.0±9.8)°. All indicators were significantly improved than those before operation ( t=40.340, P= 0.000; t=32.120, P=0.000; t=8.728, P=0.000). One-stage TKA with tibial stem extender for patients with knee arthritis and tibial stress fractures can restore limb alignment, facilitate fracture healing, and obtain the satisfactory early effectiveness.