Operative Treatment of Olecranon Fractures

Introduction:

The incidence of proximal ulna fractures is 12 per 100.000, and 10 % of all fractures in the upper extremity involve the olecranon. There are several systems classifying olecranon fractures. One of the most frequently used is the Mayo classification system as described by Cabanela and Morrey. Tension band wiring (TBW) is the most common operative technique for the treatment of olecranon fractures, and is said to be the gold standard in the treatment of non-comminuted and minimally comminuted displaced olecranon fractures. Treatment with TBW has shown good clinical results, but due to the thin layer of tissue overlying the proximal ulna, hardware issues are common. The frequency of hardware removal following TBW has been reported as high as 82 %. Only two randomized trials have compared TBW and plate fixation of olecranon fractures. Hume and Wiss compared TBW with one-third tubular plate fixation. The authors found no significant functional differences between the treatment methods, but the rate of symptomatic hardware problems was higher in the group treated with TBW. The authors also noted that loss of reduction was higher in the TBW group at final follow-up (12 months after surgery). Duckworth found no difference in patient reported outcome after one year. The sophistication in plate fixation has evolved since Hume and Wiss published their 25 years ago. The use of locking stable plate fixation in the treatment of olecranon fractures is preferred by many surgeons, especially when treating osteoporotic individuals and in cases with severe fracture fragmentation. Though locking stable implants have shown to improve fragment fixation in biomechanical and cadaveric studies, better patient reported outcome in clinical studies has yet to be proven. It is still unclear if all comminuted fractures should be treated with plate fixation, or if moderately comminuted fractures can be treated with TBW. Hardware related issues following plate fixation have also been described as a frequent problem, and rates of hardware removal up to 56 % have been reported. When approaching the issue of symptomatic hardware problems following TBW and plate fixation, one must take into consideration that the magnitude of secondary surgery is different. The removal of the two K-wires is less extensive than removing an angular stable plate fixation. Removal of symptomatic pin protrusion can be achieved in local anesthesia at the outpatient clinic, whereas plate removal routinely is done in the operating theatre, and usually requires that patient is in regional or general anesthesia. Of course, if the wire cerclage has to be removed in addition to the K-wires, the scope of the procedure is more comparable. There are strong indications that locking plate fixation yield better results when treating severely comminuted olecranon fractures, but the investigators do not know if these modern implants are superior in the treatment of moderately comminuted fractures. Even so, there is a trend toward treating all comminuted olecranon fractures with plate fixation, but the clinical evidence supporting this is limited. The investigators believe there is a need for a robust investigation in the treatment of olecranon fractures to identify the fracture patterns that adequately can be treated with TBW and the ones that should be treated with locking plate fixation.

Study aims:

The investigators want to compare an angular stable plate fixation with TBW in a randomized, controlled multi-center trial. Our hypothesis is that TBW is non-inferior in the treatment of Mayo type IIA and IIB fractures compared with an angular stable implant. The primary outcome measure is the Quick Disability of the Arm, Shoulder and Hand outcome measure (QuickDASH) at 12 months

Study design and methodology:

The study is a randomized, controlled, multicenter trial. Adult patients (18-75 years) admitted with a displaced olecranon fracture in need of surgery will be randomized to either TBW or plate fixation. The design is semi-blinded. At follow-up, an independent investigator will perform an interview and blinded functional examination, followed by an un-blinded examination and interview. Patients will be recruited at the Oslo University Hospital, and other hospitals in the region has been invited to participate in the trial. An experienced trauma surgeon will verify that the fracture meets the inclusion criteria, and the patient will be given thorough oral and written information. After signed consent, the randomization allocation to treatment method will be performed by means of a web-solution made by NTNU WebCRF system with the approval from the OUS Head of Patient Security. To secure an even dispersion in regard to age of the patients and fracture pattern, the inclusion of study patients will be stratified. This will achieve an equal randomization dispersion of patients in in the age interval from 18 to 50 years, and 50 to 75 years. Comminuted and non-comminuted fracture fractures will be randomized in the same fashion.

Power analysis and sample size:

Using the mean value of QuickDASH following olecranon fracture in a similar population, the investigators found the standard deviation (SD) to equal 12 points. The minimal clinical important difference (MCID) has been set to 8 points, and the non-inferiority limit is DASH reduction of 10 points. Level of significance (α) equals 0.05. To prove non-inferiority, a power of 0.90 and with non-inferiority limit at 10, the number required in each group is 39 patients. Taking into account a predicted loss of patients during follow-up, the investigators aim to include at least 45 patients in each group.

Follow-up:

The study patients will be followed-up over a one year period (6 weeks, 12 weeks, 12 months). The rate of hardware removal in both groups will be recorded, and the indication for removal (pain, skin protrusion/wound problems, nerve irritation etc.) will be registered and categorized. All other reoperations will be recorded as well.