Outcomes of periprosthetic distal femur fractures following total knee arthroplasty: Intramedullary nailing versus plating

BACKGROUND

Periprosthetic distal femur fractures (PPDFFs) present a challenge in terms of optimizing fixation in patients with poor bone quality and limited bone stock. The main treatment options include laterally based plating and intramedullary nailing. We hypothesized that treatment of PPDFFs with intramedullary nails would result in improved union rate, fewer complications, and an equivalent rate of malalignment compared to plating.

MATERIALS AND METHODS

Cases of PPDFFs were identified through a query of our institutional trauma database between 2011-2018. Adult patients (>18 years) were included if they sustained a fracture of the distal femur around a total knee arthroplasty (TKA) that was not initially treated at another institution. The anatomic lateral distal femoral angle (aLDFA) and the anatomic posterior distal femoral angle (aPDFA) were measured on the follow-up radiographs.

RESULTS

Ninety-seven PPDFFs in 97 patients, with a mean age of 76 years and 74% female were identified. Plating was used in 74 patients (76%) and 23 patients (24%) were treated with intramedullary nailing. Extension deformity in the sagittal plane was more common following intramedullary nailing compared to plating (10/23 nailing versus 10/74 plating) (p=0.002). There were 12 reoperations (12/75, 16%), and the method of fixation was not associated with rate of reoperation (p=0.9).

CONCLUSION

Intramedullary nailing was associated with an increased risk of malalignment, most commonly an extension deformity, in this series. However, malalignment was not associated with worse outcomes.

Non-union in lateral locked plating for distal femoral fractures: A systematic review

INTRODUCTION

This study aims to identify patient and intra-operative factors that contribute to non-union in locked lateral plating for distal femoral fractures.

METHODS

Systematic searches of English-language articles in Ovid Medline, PubMed, Embase, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews were undertaken in February 2018 according to the PRISMA guidelines. The search terms were (fracture or fracture*) AND (distal femur or distal femoral) AND (malunion or non-union). Eligible studies published at any time reported non-union rates and compared patient and intraoperative factors in patients who underwent locked lateral plating for traumatic distal femoral fractures. The quality of included papers was assessed using The Journal of Bone and Joint Surgery levels of evidence (Wright et al., 2003), and further appraised using the Downs and Black score (Downs and Black, 1998).

RESULTS

Eight studies investigating 1380 distal femoral fractures were found to satisfy the inclusion and exclusion criteria. These studies analysed a variety of patient and intra-operative factors that may contribute to non-union. These include high BMI, open fracture, comminution, fracture infection, stainless steel plate material, shorter working length, open reduction and internal fixation when compared with minimally invasive plate osteosynthesis, high construct rigidity scores and purely locking screw constructs.

CONCLUSION

This review has identified multiple factors which potentially contribute to non-union including stainless steel plate material, high construct rigidity scores and purely locking screw constructs. These findings may reflect that overly rigid plating constructs can contribute to non-union. However, they should be taken in the context of heterogeneity amongst included studies, with further research necessary to support these findings.

Lateral locked plating for distal femur fractures by low-energy trauma: what makes a difference in healing?

PURPOSE

The objective of this study is to investigate healing outcome of lateral locked plating for distal femoral fractures caused by low-energy trauma. In addition, we sought to determine predictable factors associated with fracture healing time.

METHODS

Seventy-three patients (73 fractures) with distal femur fractures (AO/OTA type 33) caused by low-energy trauma were recruited. The mean age of patients was 69.8 years (range, 43-87 years). All fractures were stabilized by less invasive osteosynthesis with anatomical periarticular locking system. Patients were followed up for mean 17.3 months (range, 6-44 months).

RESULTS

Of the 73 fractures, 52 (71.2%) fractures showed bony union within 6 months after the index surgery while the remaining 21 (28.8%) fractures showed delayed union or received revision surgery prior to complete healing. Although overall healing rate from the initial surgery was 93.2% (68/73), which seems to be satisfactory, the rate of surgical complications was 11.0% (8/73). Of all 73 fractures, seven received further surgery including three re-osteosynthesis. On multivariable analysis, plate-screw density at the fracture site was an independent predictable factor associated with the problematic healing.

CONCLUSIONS

Our findings suggest that complications related to increased healing time and fixation construct are not infrequent and ongoing problems in managing low-energy distal femur fractures. Specifically, plate-screw density at the fracture site has a significant influence on healing time in these fractures.