Fixation of periprosthetic or osteoporotic distal femoral fractures with locking plates: a pilot randomised controlled trial.
INTRODUCTION
We hypothesised that the use of a polyaxial locking plate design offers the same clinical benefits as a monoaxial locking plate system following distal femoral osteoporotic/periprosthetic fracture fixation.


METHOD
A multicentre prospective randomised pilot trial was conducted. Inclusion criteria were patients over 60 years with a displaced osteoporotic or periprosthetic distal femoral fracture. Details documented included time to union, complications, reinterventions and functional outcomes according to the Oxford knee score and EuroQol EQ-5D. Analysis of factors influencing an early fracture healing response was performed between those with clear features of radiological callus formation at three months. Statistical analysis was performed using a logistic regression model with multiple covariates assessed for each plate system (1:1 ratio) over a follow-up period of one year.


RESULTS
Forty patients (34 females) with a mean age of 77 (60-99) were recruited. Four patients deceased within the first six months. Twenty-five patients united by the six month follow-up. Six more patients progressed to union between six and nine months. Five patients developed non-union (two patients had implant failure; one in each group) and all underwent revision surgery. Malunion was evident in two cases, one with 15° of valgus (monoaxial plate), and one with 12° of recurvatum (polyaxial plate). Between the two plate systems, statistical analysis revealed no significant differences in most of the recorded parameters. Radiological features of early bone healing were present when the surgical approach was smaller (p = 0.015), and when a greater working length of the bridging plate was present (p = 0.016).


CONCLUSION
Both plate systems demonstrated good union rates and limited implant related complications. Good reduction, mechanically sound construct and respect of the local fracture biology was more important than the particular plate design characteristics.
['Kanakaris|Nikolaos K|NK|0000-0002-1695-1519', 'Obakponovwe|Oghofori|O|', 'Krkovic|Matija|M|', 'Costa|Matt L|ML|', 'Shaw|David|D|', 'Mohanty|Khitish R|KR|', 'West|Robert M|RM|', 'Giannoudis|Peter V|PV|']
D000368:Aged D000369:Aged, 80 and over D001860:Bone Plates D005260:Female D005264:Femoral Fractures D005593:Fracture Fixation, Internal D017102:Fracture Healing D006801:Humans D008297:Male D008875:Middle Aged D058866:Osteoporotic Fractures D057068:Periprosthetic Fractures D010865:Pilot Projects D011446:Prospective Studies D011474:Prosthesis Design
Femoral fracture Locking plate Polyaxial Periprosthetic fracture