Abstract
Introduction
The treatment of distal femoral fractures has undergone several changes during the past century, from non-operative techniques to more recently minimally-invasive internal fixation. The Less Invasive Stabilisation System (LISS) is an internal fixation plate that combines closed fixation of the distal femur using an anatomically pre-contoured plate with locked unicortical screws.
Study aim
The purpose of this multicentre study was to review the use of the LISS plate in three regional centres with respect to fracture healing between different severities of fractures.
Materials and methods
Patients treated with a LISS plate for a distal femoral fracture (AO/OTA Type 33A1 to 33C3) between 1st January 2004 and 1st June 2008 were recruited. Demographic data plus mechanism of injury, type of fracture, injury severity scores (ISS) and complications were documented. Subgroup statistical analysis using SPSS for Windows v. 17 was conducted to determine differences in the mean ISS, operating time, length of hospitalisation and ultimately, the time taken for union between groups of different fracture severities (Type 33A vs. Type 33C fractures). A P value of less than 0.05 was considered to be significant.
Results
Across the 3 regional centres, a total of 88 patients presented with a distal femoral fracture, of which 44 were treated with a LISS plate. The mean age of the patients was 66.1 (range 9 - 99), with 15 males and 29 females. There were 14 Type 33A1, 13 Type 33A2, 6 Type 33A3, 1 Type 33B2, 1 Type 33C1, 5 Type 33C2 and 4 Type 33C3 fractures. Union was achieved within an average of 14.7 weeks (range 8 - 25) in 33 cases. Five cases exhibited non-union and were managed by a retrograde nail or another locking compression plate. Six cases developed delayed union. Subgroup analysis revealed that patients with Type 33C (n = 10) fractures presented with a significantly greater mean ISS score (12.7 vs. 10.0, p = 0.031), endured longer operating time (203.7 minutes vs. 125.8 minutes, p = 0.016) and spent longer in hospital compared to Type 33A (n = 33) fractures (35.3 days vs. 12.5 days, p = 0.004). However, no difference in the mean time for radiological union between the groups was observed (16.4 weeks vs. 13.6 weeks, p = 0.058).
Discussion
We observed an overall success rate of 75% (33 out of 44 cases) as fractures reached radiological union within an average of 14.7 weeks. Interestingly, despite a greater mean ISS score and operating time among Type 33C fractures, the subgroup analysis confirmed that the LISS plate is a robust treatment option across all fracture severities, as this did not translate as longer time to union compared to Type 33A fractures. However, there were 5 cases of non-union and 6 cases of delayed union in our series. These may have arisen due to lack of precision in surgical technique, as we observed 8 cases of suboptimal implant positioning. Three cases involved distal screws lacking contact with the medial cortex of the femur. Overall, our data suggest a favourable outcome for the LISS plate in the treatment of distal femoral fractures.
