A Trial of Plate Fixation Versus Tension Band Wire for Olecranon Fractures

Background

Proximal forearm fractures comprise approximately 5% of all fractures, whilst olecranon fractures account for almost 20% of fractures occurring around the elbow1. There is limited conclusive evidence regarding the epidemiology, optimal treatment and outcome of isolated olecranon fractures.

Patients with undisplaced olecranon fractures can be treated non-operatively2,3. The aims of treatment in displaced olecranon fractures are the restoration of function and stability to the elbow joint4. The technique employed should allow preservation and reconstruction of the articular surface with minimal associated complications. Tension-band wiring (TBW) is the most recognised and commonly used fixation method, although plate fixation and intramedullary screw fixation are noted alternatives2,4-10. Potential problems with the TBW technique are wound breakdown, infection, prominent metalwork, malunion and non-union2,4,7,11-13. Furthermore, plate fixation is considered to be superior in distal/comminuted/oblique fractures and fracture-dislocations, with superior fracture reduction and fixation results, as well as a lower rate of re-operation2,5,13,14. There is only one prospective randomized trial in the literature comparing TBW and plate fixation for displaced olecranon fracture13. The major conclusions from this study were:

• The functional outcome at six months was not significantly different in the two groups
• Post-operative loss of fracture reduction (53% vs 5%) and prominent symptomatic metalwork was more frequently observed after TBW

This study was performed in 1992 with less sophisticated plates when compared with the location specific plates currently available.

Research Aim

To determine if any difference exists in outcome (primary measure - DASH score) after one year between open reduction and internal fixation with tension band wiring AND plate and screw fixation for olecranon fractures.

Methodology

This trial involves identifying patients under the age of 75yrs (<75yrs) presenting to the Edinburgh Orthopaedic Trauma Unit with an isolated olecranon fracture requiring operative intervention. Patients who consent to enrol in the trial will be randomised to one of two recognised operative fixation techniques - tension band wire fixation or plate fixation. The trial will commence once ethical approval is granted by the Lothian Research Ethics Committee.

All statistical analysis was/will be performed by Dr Rob Elton. Prior to the study a power analysis determined the number of patients required in each trial. The primary outcome measure will be the DASH score, a continuous variable that follows a normal (Gaussian-shaped) distribution. This study is designed to determine a clinically relevant mean difference of 10 points between the two cohorts at one year after enrolment. A power analysis indicated that a total sample size of 50 (25 in each group) subjects will provide 80% statistical power to detect significant differences (0.05) in DASH scores, assuming an effect size of 0.8 (mean difference of 10 points, standard deviation of 12 points) using an unpaired t-test. To account for a possible loss to follow-up of up to 25%, we anticipate enrolling 35 subjects in each cohort for a total sample size of 70 subjects. A p value of < 0.05 was considered statistically significant.

All adult patients presenting to the Edinburgh Orthopaedic Trauma Unit with a fracture of the olecranon that satisfy the inclusion criteria will be invited to participate in our study. All adult patients with an olecranon fracture best treated operatively are eligible for enrolment in this study regardless of sex, race or ethnicity. Vulnerable populations will not be recruited.

A qualified member of the on-call team will introduce the study to the patient and initiate informed consent. If the patient agrees, a research fellow (Trauma and Orthopaedic StR3 level), not involved with the patient's care will review the study protocol in detail and address any questions the patient may have. If the patient is willing to participate, the research fellow will complete the informed consent. Patients will be given a copy of the consent form, and be informed that their participation is voluntary and that they can withdraw at any time during the study without detriment to their normal care in any way. Patients may take as long as they like to consider participation, provided that they still meet all the eligibility criteria documented above. Patients that are willing to participate in this study will get the same care of their fracture as patients that decide not to participate in the study.

On enrolment, a data collection form will be started with demographic and injury-related information collected. Prior to surgery, patients will be randomised (performed by Dr Rob Elton using closed opaque envelopes) into one of the two groups (tension band wire fixation or plate fixation). Following surgery, the post-operative assessment and course will be as per normal protocol for patients who are not in this study. Patients will be immobilised depending on fracture fixation during surgery and the decision will be made by the treating surgeon. Physiotherapy will be arranged when required

Follow-up All follow-up assessment will take place during follow-up visits initially with the treating consultant surgeon's team and a dedicated research physiotherapist. Radiographs and other diagnostic studies will be obtained at the discretion of the treating surgeon and will not differ from routine clinical care.

Follow-up assessment will be collected over a one year period (2 weeks, 6 weeks, 3 months, 6 months and one year). Routine follow-up in our institution for patients who have sustained an olecranon fracture that is managed operatively involves outpatient clinic reviews with radiographs at 2 weeks, 6 weeks, three months and six months. Therefore, one additional visit at 1 year is required for this study with no additional radiographs. Radiographs will only be performed at one year on clinical indication.

At each visit physical examination, treatment, complications and re-operation (e.g. hardware removal), for each patient will be recorded. A research physiotherapist, blinded to the treatment method by sticking plaster over the entry position, will undertake functional testing and assessment.

Outcome and statistical methods By statistically analysing the outcome scores in the two groups, I aim to better determine the optimal management of this fracture in this age group. Using univariate analysis and multivariate regression analysis I will determine significant (p<0.05) predictors of outcome in relation to functional outcome score (DASH at one year).