Long term outcome of patella fractures:open reduction and internal fixation with stainless steel wire vs.non-absorbable braided polyester suture

Objective To determine the long term outcome of patella fractures managed surgically with two different types of fixation:stainless steel wire or non-absorbable,braided,polyester suture.Design A prospective trial where patients were recruited in a consecutive fashion between the years 2000 and 2005 and randomized into 2 treatment groups through random number generation and number assignments in sealed envelopes.Patients were blinded to the treatment group assigned.Surgical technique and post-operative protocol was the same for each group.Subjects Patients were over the age of 16 and medically fit who presented with a displaced patella fracture requiring operative fixation.Patients were able to give consent and could follow post-operative rehabilitation requirements.Interventions In the 2 groups,open reduction and internal fixation of the patella fractures was standardized with 2 longitudinal K-wires and a figure of eight tension band using either 18 G stainless steel wire or 2 #5 ethibond sutures.Outcome Measures The primary outcome measure was re-operation rate.Secondary outcomes included surgical procedure time,the presence of clinical and radiographic union,and validated functional outcome measures (knee questionnaire,Euroqol EQ-SD,SF-36)collected from patients at final follow up.Results Almost all patients were followed to clinical and radiographic union(20/22).Average follow-ups for the stainless steel wire and suture groups were 4 and 2.3 years respectively.The re-operations in the wire and suture groups was 4 (of 11)and 5(of 11)respectively.The majority of re-operations were due to longitudinal K-wire related irritation (6/9).The wire group had a slightly shorter average surgical time than the suture group(33 vs.44 minutes),which was not statistically significant.Long term functional outcome scores indicated that there was some residual disability in patellar fracture patients,although this was not debilitating.Conclusions We suggest that a major determinant of re-operation for patella fracture fixation in a tension band technique is unnecessary longitudinal K-wire length.Suture can be as good as wire in achieving clinical and radiographic union of patella fractures.Patients with patellar fractures can achieve a reasonable functional outcome but will have a high chance of re-operation during their recovery period.