Periprosthetic supracondylar femoral fractures following total knee arthroplasty: clinical comparison and related complications of the femur plate system and retrograde-inserted supracondylar nail

Abstract

Background: The purpose of this study is to analyze the clinical results and related complications of the femur plate system (FP) and the retrograde-inserted supracondylar nail (RISN).

Materials and methods: The study included 42 cases of periprosthetic supracondylar femoral fractures (PSF) proximal to posterior stabilized total knee arthroplasty between 2005 and 2009. Twenty-four cases of PSF were treated with the FP, and the other 18 cases were treated with the RISN. This study cohort was divided into subgroups according to the AO classification. We retrospectively compared the clinical results between the FP and RISN group.

Results: There were no significant differences between the two groups in terms of time of clinical union (p = 0.649). In the subgroup analysis, the mean operation time was significantly different only in subgroup A1 (p = 0.03). Complications were seen in 29.2 % (7/24) of patients in the FP group and 27.8 % (5/18) in the RISN group. The age during the index TKA and fracture fixation was a significant risk (p = 0.008) factor for complications between the two groups. No significant differences were found in the other factors between the two groups. The p value for operative time (p = 0.223), immobilization period (p = 0.129), ROM (p = 0.573), KSS (p = 0.379), KSS functional scores (p = 0.310) and time to union (p = 0.649).

Conclusion: Clinical results did not differ according to the treatment methods used. Fixation method and fracture type did not cause an increase in the complication rate, but there was a trend toward higher non-union rates with the FP method and higher re-fracture rate with the RISN method. Noting the fact that only increasing age correlated with an increased complication rate, more careful attention should be paid to elderly patients in terms of both prevention and surgical care.

Level of evidence: Level III, therapeutic study.

Fig. 1

a Case 1. Preoperative X-rays of a periprosthetic fracture of the left knee in a 75-year-old man. b Radiograph of metal failure with the FP system taken 6 months later. c Follow-up radiograph taken 2 years later after fracture fixation with the RISN showing callus formation

Fig. 2

a Case 2. Preoperative X-rays of a periprosthetic fracture of the right knee in a 62-year-old woman. b A radiograph of refracture at the tip of the retrograde nail taken 3 months later after the RISN fixation. c Follow-up radiograph taken 2.5 years later after fracture fixation with a femoral intramedullary nail showing callus formation