Abstract
Introduction
The management of peri-prosthetic distal femur fractures following TKR (Total Knee Replacement) in the elderly remains a challenge with little or no consensus on the best available treatment. Various methods have been described in the management of these complex fractures. Our study compares the outcome and cost of distal femoral arthroplasty to that of Fixation (Plating/Retrograde Nailing).
Methods
We retrospectively reviewed our database for patients admitted with peri-prosthetic distal femoral fractures between 2005–2013 (n=61). The patients were stratified into 2 groups based on method of management. The Distal Femoral Arthroplasty group (Group A) had 21 patients, with a mean age of 78 years (68–90. The Fixation group (Group B) had 40 patients, with a mean age of 74 years, 23 of those had plating of the fracture, while 17 had a retrograde nail inserted.
Pain scores, Length of stay, intra-operative blood loss, and weight bearing status, were compared. Functional outcomes were also assessed using Oxford knee scores, KSS scores, VAS pain assessment and range of motion from last follow up appointment. Minimum follow-up was 2 years.
Cost analysis was done for both groups, which included implant costs, consumable costs (man power included), theatre utilisation time and length of hospital stay. The calculation was done based on the PbR (payment by results) system and “best practise tariffs 2010–11” utilised by the NHS (National Health Service) in England.
Results
In group A, the average surgical time was 116 minutes with mean blood loss of 400 ml. In group B, the mean surgical time was 123 minutes with average blood loss of 800 ml.
The mean length of hospital stay in group A was 9 days whereas in group B was 32 days. All patients were fully weight bearing by day 1.5(range 1–3 days) in group A, compared to a mean of 11 weeks in group B.
Mean Oxford score was 28 and KSS score was 70 in group A compared to 27 and 68 in group B. The pain score on VAS was 2 for group A and 1.5 for group B. The mean ROM of the knee was 95° in group A and 85° in group B.
We had 4 complications in group A. There were 2 deaths due to medical co-morbidities, 1 superficial infection, and 1 DVT. In the fixation group, there were 6 deaths due to medical co-morbidities, 1 failure of fixation, 6 mal-unions, 1 non-union and 2 infections.
Overall, the distal femoral arthroplasty procedure costs approximately £10000, and the fixation group costs were on average of £9800.
Discussion & Conclusion
Distal femoral arthroplasty allowed early mobilisation, thus avoiding prolonged hospital stay and reducing the risk of inpatient related morbidity. Complication rates were lower than the fixation group and the overall costs were comparable to that of fixation.
Distal femoral arthroplasty appears to be a promising alternative treatment to internal fixation in elderly patients with distal femoral peri-prosthetic fractures. With appropriate patient selection, the prosthesis is likely to survive for the duration of patient's lifetime.
