Surgical treatment of olecranon fracture
The bony tip of the elbow is called the olecranon. It is shaped to allow bending and straightening of the arm at the elbow. The olecranon sits directly under the skin of the elbow, which makes it vulnerable to injury and fracture (break) following a fall. When this happens, people are sometimes unable to straighten their arms. Treating this fracture usually involves an operation to re-position the broken parts of the bone and then fix them in place using wires, pins, plates, screws and other devices.
Description of the studies included in the review
We searched the medical literature until September 2014 and found six trials, involving 244 adults with olecranon fractures. Each trial tested a different comparison. Tension band wiring, which is a commonly used technique for fixing these fractures, was the 'control' intervention in five trials.
Quality of the evidence
All six trials were small and had weaknesses that could affect the reliability of their results. We judged the overall quality of the evidence available for each comparison as either low or very low.
Summary of the evidence
One trial compared the use of plate fixation with tension band wiring. It found that more people had pain-free elbow motion after plate fixation and fewer people had discomfort from metalwork prominence, which is a well-known problem with wire fixation where the metal wiring on the surface of the bone just under the skin causes pain, discomfort and other problems.
Four trials compared different ways of wiring the fracture. Two trials found very little clear evidence of any differences between them. One trial found that adding an intramedullary screw (this is a screw that was inserted through the bone and along the central bone canal) to standard tension band wiring reduced the risk of the metalwork under the skin being prominent. Another trial found that the cable pin system improved function and resulted in fewer complications compared with standard tension band wiring.
Finally, one trial compared a new method of fixation using a titanium-nickel device that once implanted takes the shape of the olecranon with locking plate fixation. It found no clear evidence of differences between the techniques in patient-reported function and complications (the only complication was a superficial infection).
Currently, there is not enough evidence to determine the best treatment for these fractures with confidence. Further high quality research is needed, which is likely to have an important impact on our confidence in the estimates of the effects and will likely change the estimates.
There is insufficient evidence to draw robust conclusions on the relative effects of the surgical interventions evaluated by the included trials. Further evidence, including patient-reported data, on the relative effects of plate versus tension band wiring is already pending from one recently completed RCT. Further RCTs, using good quality methods and reporting validated patient-reported measures of function, pain and activities of daily living at set follow-ups, are needed, including checking positive findings such as those relating to the use of an intramedullary screw and the cable pin system. Such trials should also include the systematic assessment of complications, further treatment including routine removal of metalwork and use of resources.
Fractures of the olecranon (the bony tip of the elbow) account for approximately 1% of all upper extremity fractures. Surgical intervention is often required to restore elbow function. Two key methods of surgery are tension band wire fixation and plate fixation.
To assess the effects (benefits and harms) of different surgical interventions in the treatment of olecranon fractures in adults.
We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (22 September 2014), the Cochrane Central Register of Controlled Trials (CENTRAL, 2014, Issue 8), MEDLINE (1946 to September week 2 2014), EMBASE (1980 to 19 September 2014), trial registers, conference proceedings and reference lists of articles.
Randomised controlled trials (RCT) and quasi-RCTs that compared different surgical interventions for the treatment of olecranon fractures in adults.
Two review authors independently performed study selection, risk of bias assessment and data extraction. The primary outcomes of this review were function, pain and adverse events.
We included six small trials involving 244 adults with olecranon fractures. Of these, four were RCTs and two were quasi-RCTs; both of were at high risk of selection bias. All six trials were at high risk of performance bias, reflecting lack of blinding, and four trials were at high risk of detection bias. The quality of the evidence for most outcomes was generally very low because of limitations in study design and implementation, and either imprecision of the results or inadequate outcome measures. Thus, we are very uncertain about the estimates of effect.
One trial (41 participants) comparing plate fixation with standard tension band wiring provided very low quality evidence at 16 to 86 weeks' follow-up of a better clinical outcome after plate fixation (good outcome (little pain or loss of elbow motion): 19/22 versus 9/19, risk ratio (RR) 1.82 favouring plate fixation, 95% confidence interval (CI) 1.10 to 3.01). There was very low quality evidence of less symptomatic prominent metalwork after plate fixation (1/22 versus 8/19; RR 0.11, 95% CI 0.01 to 0.79). The results for other adverse effects (infection and delayed or non-union) were inconclusive. Evidence is pending from a newly (September 2014) completed trial (67 participants) making the same comparison.
Four trials compared four different modified techniques of tension band wiring (i.e. additional intramedullary screw fixation, biodegradable pins, Netz pins and cable pin system) versus standard tension band wiring. There was very low quality evidence of little difference at six to 14 months in function assessed by a non-validated scoring tool from the addition of an intramedullary screw. However, there were fewer cases of metalwork prominence in the intramedullary screw group (1/15 versus 8/15; RR 2.00, 95% CI 1.15 to 3.49; one trial; 30 participants). There was very low quality evidence from one trial (25 participants) of little difference in subjectively or objectively assessed good outcome at a mean of 20 months between tension band wiring with biodegradable implants versus metal implants. There were no adverse events, either non-union or sinus or fluid accumulation, reported. All 10 participants in the metalwork group had an extra operation to remove their metalwork at one year. One trial, which did not report on function or pain, provided very low quality evidence of lower rates of metalwork for any reason or for symptoms after Netz pin tension band wiring compared with standard tension band wiring (11/21 with Netz pin versus 17/25 with standard tension band wiring; RR 0.77, 95% CI 0.47 to 1.26; 46 participants); this evidence also supports the possibility of higher rates of metalwork removal for Netz pins. Two intra-operative complications occurred in the Netz pin group. The fourth trial, which compared the cable pin system with standard procedure, found low quality evidence that cable pin improved functional outcome at a mean of 21 months (Mayo Elbow Performance Score (MEPS), range 0 to 100: best outcome: mean difference (MD) 7.89 favouring cable pin, 95% CI 3.14 to 12.64; one trial; 62 participants). It also found low quality evidence of fewer postoperative complications in the cable pin group (1/30 with cable pin system versus 7/32 standard tension band wiring; RR 0.15, 95% CI 0.02 to 1.17), although the evidence did not rule out the converse.
One trial provided very low quality evidence of similar patient-reported function using the Disabilities of the Arm, Shoulder and Hand questionnaire (0 to 100: worst function) at two or more years after fixation using a novel olecranon memory connector (OMC) compared with locking plate fixation (MD -0.70 favouring OMC, 95% CI -4.20 to 2.80; 40 participants). The only adverse event was a superficial infection in the locking plate group.