Low-profile double plating of unstable osteoporotic olecranon fractures: a biomechanical comparative study

Olecranon Fractures: A Critical Analysis Review

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Olecranon fractures account for 10% of all elbow fractures and are more likely to result from a low-energy injury. A displaced fracture with a stable ulnohumeral joint (Mayo type 2) is the most common type of injury.

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The management of an isolated olecranon fracture is based on patient factors (age, functional demand, and if medically fit to undergo surgery) and fracture characteristics including displacement, fragmentation, and elbow stability.

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Nonoperative management can be successfully used in undisplaced fractures (Mayo type 1) and in displaced fractures (Mayo type 2) in frail patients with lower functional demands.

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Patients with displaced olecranon fractures with a stable ulnohumeral joint without significant articular surface fragmentation (Mayo type 2A) can be managed with tension band wiring, plate osteosynthesis (PO), intramedullary fixation, or suture repair.

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PO is advocated for multifragmentary fractures and fractures that are associated with ulnohumeral instability. It is essential to consider the variable anatomy of the proximal ulna during surgery.

Efficacy and safety of tension band wire versus plate for Mayo II olecranon fractures: a systematic review and meta-analysis

Purpose

For olecranon fractures, the choice of tension band wire (TBW) or plate fixation has long been controversial. Therefore, this study aimed to evaluate the efficacy and safety of TBW and plate in the treatment of patients with Mayo II olecranon fractures by Meta-analysis.

Methods

PubMed, Embase, Cochrane, the Web of Science, China National Knowledge Infrastructure, Wanfang, and China Biomedical Database were searched for randomized controlled trials (RCTs) and cohort studies (CSs) where TBW was compared with plate for Mayo II olecranon fractures (OF). Subsequently, the data were extracted by two reviewers independently and were analysed via RevMan5.4.1. Besides, mean difference (MD), risk ratio (RR), and 95% confidence intervals (CIs) were calculated. Furthermore, Cochrane Risk of Bias Tool 2.0 and Newcastle–Ottawa Scale were adopted for assessing the risk of bias.

Results

A total of 1RCT and 10 CSs were included, when 449 cases were treated with TBW and 378 with plate. The plate has favourable postoperative long-term (≥ 1 year) functional score in MEPS (MD: − 3.06; 95% CI − 5.50 to 0.62; P = 0.01; I² = 41%) and Dash score (MD: 2.32; 95% CI 1.91, 2.73; P < 0.00001; I² = 0%), also carrying fewer complications (RR: 2.13; 95% CI 1.48, 3.08; P < 0.0001; I² = 58%). Besides, there exists no significant difference in postoperative long-term (≥ 1 year) elbow flexion (MD: − 1.82°; 95% CI − 8.54, 4.90; P = 0.60; I² = 71%) and extension deficits (MD: 1.52°; 95% CI − 0.38, 3.42; P = 0.12; I² = 92%). Moreover, TBW is featured with a shorter operation time (MD = − 5.87 min; 95% CI − 7.93, − 3.82; P < 0.00001; I² = 0) and less intraoperative bleeding (MD: − 5.33 ml; 95% CI − 8.15, − 2.52; P = 0.0002; I² = 0). In terms of fracture healing time, it is still controversial. Furthermore, the subgroup analysis has revealed that for Mayo IIA OF, the plate has a better outcome in the long-term (≥ 1 year) postoperative MEPS, the Dash score, and the incidence of postoperative complications than TBW, while there is no significant difference in the long-term (≥ 1 year) postoperative elbow motion between two groups.

Conclusions

Plate has better efficacy and safety for Mayo II OF. Considering that few studies are included in the meta-analysis, more high-quality RCTs are still required to confirm these findings.

PROSPERO registration number: CRD42022313855.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03262-7.

Lag screw osteosynthesis of simple olecranon fractures: A biomechanical comparative study

Olecranon fractures are most frequently stabilized by tension band wiring (TBW), which unfortunately leads to relevant implant removal rates due to K-wire migration and soft tissue irritation. As lag screw osteosynthesis (LSO) might be a gentle and effective alternative in simple fracture patterns, the goal of the present study was to biomechanically compare LSO with TBW in simple olecranon fractures at a cadaver model. A simple olecranon fracture (Mayo type IIA) was created in eight pairs of human cadaver elbows, which were pairwise fixed by either TBW or two transcortical 4.0 mm lag screws. Biomechanical testing was conducted as a pulling force, applied to the triceps tendon in a 90° position. First, cyclic loading between 10 and 300 N was performed for 50,000 cycles. Afterward, maximum load was raised by 0.02 N/cycle until construct failure, what was defined as displacement >2 mm. Besides fracture displacement, failure cycle and failure load, the modes of failure were analyzed. Within the first five cycles, there was no significant difference in displacement (median TBW: 0.2 mm; LSO: 0.5 mm; p = 0.091). Both after 2000 (median TBW: 0.2 mm; LSO: 0.6 mm; p = 0.042) and after 20,000 cycles (median TBW: 0.4 mm; LSO: 0.9 mm; p = 0.027), the difference was significant. Failure cycle (median TBW: 72,639 cycles; LSO: 43,429 cycles; p = 0.017) and failure load (median TBW: 702 N; LSO: 303 N; p = 0.025) differed significantly as well. TBW mostly (6/8) failed at the lock of the cerclage wire, whereas most LSO constructs (5/8) failed as a pullout of the proximal fragment. In conclusion, to our biomechanical findings at human cadaver specimens, simple olecranon fractures treated by LSO show higher dislocation rates and lower failure loads compared to conventional TBW and mostly fail by pullout of the proximal fragment.

Biomechanical comparison between double-plate fixation and posterior plate fixation for comminuted olecranon fracture using two triceps screws in synthetic bone model

BACKGROUND

Although preventing triceps fragment displacement is essential for treating an olecranon fracture, we frequently encounter situations in which only a few screws can be fixed to the triceps fragment. The aim of this study was to compare the stability of double-plate fixation and posterior plate fixation for olecranon fractures when the triceps fragment was small and only 2 screws could be inserted.

METHODS

A composite ulna model was used to simulate olecranon fracture. Four groups were formed consisting of double-plate and posterior plates with cortical and locking screws. The cyclic loading test was conducted for 500 cyclic loads of 5 to 50 N on a specimen to measure micromotion and displacement of the gap caused by light exercise. The load-to-failure test was performed by applying a load until fixation loss, defined as when the fracture gap increased by 2 mm or more or catastrophic failure occurred, to measure the maximum load.

RESULTS

Eight samples per group were tested through the pilot study. All groups were stable with a micromotion of <0.5 mm. However, the mean micromotion showed significant differences between the 4 groups (P < .001, Table 1). In the mean micromotion during exercise, posterior plating with cortical screws was the most stable (0.09 ± 0.02 mm) while double-plating with cortical screws was the most unstable (0.42 ± 0.11 mm). At the maximum load, posterior plating with locking screws was the strongest (205.3 ± 2.8 N) while double-plating with cortical screws was the weakest (143.3 ± 27.1 N). There was no significant difference in displacement after light exercise between the groups.

CONCLUSIONS

This study showed that when 2 triceps screws were used, both groups were stable during light exercise, but posterior-plating was stronger than double-plating.