Comminuted olecranon fractures: biomechanical testing of locked versus minifragment non-locked plate fixation

Adjunct fixation in upper extremity long bone fracture plating

PURPOSE

A variety of adjunct fixation methods to supplement primary plate and screw constructs are available. There are no large clinical series of these techniques in the upper extremity. The purpose of this study was to review patients with upper extremity fractures that underwent primary plating with adjunct fixation.

METHODS

This study was a retrospective review of plate fixation of humeral, radial and ulnar fractures over a 12-year period. Measurable outcomes for this study included rates of non-union, complications, and implant removal.

RESULTS

Thirty-nine humeral shaft fractures had supplemental fixation 97% of the time, with a 100% union rate. Supplemental fixation was used in 79% of forearm cases. There was a 98% initial union rate in 48 acutely plated forearm fractures.

CONCLUSION

Although a variety of techniques were employed, the mini-fragment (2.7 mm or smaller) was the most common strategy for adjunctive fixation of long bone fractures in the upper extremity.

Biomechanics of plate fixation following traditional olecranon osteotomy versus novel proximal ulna osteotomy for visualizing a distal humerus injury

After a distal humeral injury, olecranon osteotomy (OO) is a traditional way to visualize the distal humerus for performing fracture fixation. In contrast, the current authors previously showed that novel proximal ulna osteotomy (PUO) allows better access to the distal humerus without ligamentous compromise. Therefore, this study biomechanically compared plating repair following OO versus PUO. The left or right ulna from eight matched pairs of human cadaveric elbows were randomly assigned to receive OO or PUO and repaired using pre-contoured titanium plates. Destructive and non-destructive mechanical tests were performed to assess stability. Mechanical tests on OO versus PUO groups yielded average results for ulna cantilever bending stiffness at a 90° elbow angle (29.6 vs 30.5 N/mm, p = 0.742), triceps tendon pull stiffness at a 90° elbow angle (28.2 vs 24.4 N/mm, p = 0.051), triceps tendon pull stiffness at a 110° elbow angle (61.9 vs 59.5 N/mm, p = 0.640), and triceps tendon pull failure load at a 110° elbow angle (1070.1 vs 1359.7 N, p = 0.078). OO and PUO elbows had similar failure mechanisms, namely, tendon tear or avulsion from the ulna with or without some fracture of the proximal bone fragment, or complete avulsion of the proximal bone fragment from the plate. The similar biomechanical stability (i.e., no statistical difference for 4 of 4 mechanical measurements) and failure mechanisms of OO and PUO plated elbows support the clinical use of PUO as a possible alternative to OO for visualizing the distal humerus.

Elimination of irreducible intercalary fragment and fixation using locking plate for Mayo type IIB olecranon fracture-outcomes compared with type IIA

BACKGROUND

We hypothesized that the outcomes of articular reduction with elimination of irreducible articular intercalary fragments for Mayo type IIB fractures fixed using olecranon locking plates would be as satisfactory as those of noncomminuted fractures.

METHODS

A total of 65 patients were enrolled from among 92 who had undergone operative treatment for olecranon fractures between March 2008 and February 2015. Patients with fragments that were eliminated because they were too comminuted to be fixed during surgery (type IIB) were included in group 1. Patients without intraarticular comminuted fragments (type IIA) or with very few fragments were assigned to group 2. In group 1, articular congruency and reduction status were confirmed by direct visualization. The fracture was then fixed with a locking plate and irreducible intercalary fragments were eliminated.

RESULTS

There were no significant differences in demographic characteristics, such as age and gender, between the two groups. Both groups achieved bony union within the approximately 6-year follow-up period and there were no serious complications in either group. The grades of heterotrophic ossification and ulnohumeral arthritis were not significantly different between the groups. The mean flexion-extension and pronation-supination arcs were similarly satisfactory in both groups (127.35° and 134.39° vs. 129.69° and 133.75° in groups 1 and 2°, respectively). Clinical outcomes including visual analog scale pain scores, as well as the Mayo Elbow Performance scores (87.73 vs. 88.28 in groups 1 and 2, respectively), were also similarly satisfactory in both groups.

CONCLUSIONS

Locking plate fixation under direct visualization (to reduce the articular surface in Mayo type IIB fractures) and elimination of articular intercalary fragments resulted in satisfactory radiologic and clinical outcomes, similar to those of noncomminuted fractures also treated using a locking plate.

LEVEL OF EVIDENCE

Level IV, Retrospective therapeutic study.

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.

Comparison of clinical outcomes of three internal fixation techniques in the treatment of olecranon fracture: a retrospective clinical study

OBJECTIVE

The application of double plating in olecranon fractures is becoming increasingly widespread. There is no research comparing this technique with traditional tension band wiring (TBW) and the single plate technique. The purpose of this study was to compare the efficacy of three fixation techniques in olecranon fractures.

MATERIALS AND METHODS

From March 2016 to May 2020, we collected the clinical data of 95 patients with olecranon fractures who underwent surgical treatment. Thirty-five patients received TBW surgery (TBW Group), 32 patients received a 3.5 mm locking compression plate (LCP, 3.5 mm LCP Group), and 28 patients received double mini-locking plate treatment (DP Group). The operation time, fracture union time, time of return to work, range of motion (ROM), soft tissue stimulation to remove internal fixation, and patient-related functional results (the Weseley score, Mayo Elbow Performance Score [MEPS], and Disabilities of Arm, Shoulder and Hand Score [DASH]) were recorded. The clinical results and complications of the three internal fixation techniques were compared.

RESULTS

The average follow-up time was 15.011.82 months (12-18 months). All patients' fractures healed by first intention. There were no statistically significant differences in the operation time, fracture union time, ROM, Weseley score, MEPS or DASH scores of the three groups of patients. The postoperative return time for patients in the TBW group was 10.002.15 weeks, the 3.5 mm LCP group was 9.561.93 weeks, and the DP group was 8.432.38 weeks (P = 0.014); 12 patients in the TBW group required removal of plant due to soft tissue stimulation, the 3.5 mm LCP group had 8 cases, and the DP group had 2 cases (P = 0.038).

CONCLUSION

The postoperative clinical results and elbow joint function of patients with olecranon fractures fixed by tension band wiring, 3.5 mm LCP and double mini-locking plate are similar, which indicates that double-plate technology can be used as an alternative to the two groups of traditional techniques. In addition, double-plate technology also helps patients return to work earlier and has a lower incidence of soft tissue stimulation.

Mini-fragment plating of olecranon fractures is comparable to precontoured small-fragment plating

INTRODUCTION

Though long-term functional outcomes of olecranon fracture plate fixation are favorable, postoperative implant irritation commonly leads to elective removal. We hypothesized that mini-fragment plates will decrease implant removal compared to precontoured plates.

METHODS

Patients with isolated olecranon fracture (AO/OTA 2U1-B1) treated with plate fixation were retrospectively reviewed. Patients were stratified into groups based on whether they underwent open reduction and internal fixation with a (1) surgeon contoured mini-fragment or (2) precontoured olecranon-specific plate. Rates of symptomatic implants and implant removal were compared.

RESULTS

98 and 32 patients were treated with precontoured and mini-fragment plates, respectively. Baseline demographics and comorbidities were similar. Mean follow-up was 20.6 months. There were no differences in rates of postoperative complication (22/98, 22.4% vs. 5/32, 15.6%; p = 0.41) or reoperation (37/98, 37.8% vs. 8/32, 25%; p = 0.19). Symptomatic implants were common in the precontoured cohort (44/98, 44.9% vs. 7/32, 21.9%; p < 0.05). Implant removal rates were 36.7% and 18.8%, respectively (p = 0.06).

DISCUSSION/CONCLUSION

Olecranon fracture stabilization with mini-fragment plate is associated with lower rates of symptomatic implants, with no difference in postoperative complications or reoperations. Mini-fragment plating is a safe and promising alternative to precontoured plating.

Predrilled locking compression plate is more accurate than tension band wiring in restoring articular geometry of the ulnar greater sigmoid notch after olecranon Chevron osteotomy

INTRODUCTION

The olecranon Chevron osteotomy (OCO) is commonly used to approach complex intra-articular fractures of the distal humerus. Predrilled tension band wiring (TBW) has historically been used to fix OCO. However, clinical outcomes are burdened by secondary loss of reduction and up to 21.3% non-union rates. The biomechanical stability of anatomic locking compression plate (LCP) was reported to be superior to TBW in olecranon fracture fixation. We hypothesised that this implant may also be superior to TBW in the anatomic reconstruction of the articular surfaces of the ulnar greater sigmoid notch after OCO by predrilling the holes of the angular stable plate with the threaded drill guide prior to osteotomy.

MATERIALS AND METHODS

Lateral standardised and calibrated radiographs of twenty synthetic ulnar bones were obtained using a custom-made holder prior to preparation by a senior orthopaedic trauma surgeon. Ten specimens were then predrilled using the threaded drill bit guide of an olecranon LCP, while the other ten samples were predrilled with two 1.6 mm Kirschner wires. A distal "V" OCO was performed using a 0.6 mm oscillating saw. After repositioning and fixation with the corresponding device, lateral radiographs were repeated. Two independent observers used the TraumaCad planning software to document the articular geometry of the ulnar greater sigmoid notch pre- and postoperatively. The diameter of the best-fitting circle (diameter), the distance between the tip of the coronoid and the olecranon processes (distance) and the maximum articular depth were measured.

RESULTS

With the TBW technique, after OCO and fixation, all three postoperative measurements were significantly (p≤0.001) different from preoperative measurements. The diameter and distance increased by a mean of 1.5±0.5 mm and 0.9±0.3 mm, respectively, while the depth decreased by a mean of 0.2±0.1 mm. In contrast, no significant differences between pre- and postoperative measurements were observed with the LCP technique (p≥0.13). Inter and intra-observer measurement reliability was strong to very strong (intraclass correlation coefficients≥0.793) for all three variables.

CONCLUSION

Our study reveals that the predrilled LCP technique is more accurate than the predrilled TBW in restoring the anatomic articular geometry of the ulnar greater sigmoid notch after OCO.

Clinical evaluation of double-plate osteosynthesis for olecranon fractures: A retrospective case-control study

INTRODUCTION

Single, dorsal plating is a commonly used technique for treating olecranon fractures. Double-plate osteosynthesis is an alternative treatment. Aim of this study was to present the surgical technique using this novel double-plate implant for olecranon fractures and review clinical results, complication rates and revision surgeries. Results were compared to single, dorsal plating.

HYPOTHESIS

Does double-plate osteosynthesis for olecranon fractures improve material's tolerance with respect to osteosynthesis by single dorsal plating?

PATIENTS AND METHODS

Between February 2011 and March 2015, we retrospectively evaluated 47 patients who were included in this study: 25 were treated with a low-profile double-plate osteosynthesis and 22 with an anatomically pre-shaped 3.5mm locking compression plate (LCP). The 2 groups were the result of a change of implants in our department in 2013. Patient satisfaction, range of motion, patient related outcome scores (Mayo Elbow Performance Score [MEPS], Disabilities of Arm, Shoulder and Hand Score [DASH]), complications and revision surgeries were evaluated. Results between both implant types were statistically compared using the Mann-Whitney U test.

RESULTS

After a mean follow-up of 41 months (range: 25-61), the low-profile double-plate group showed a range of motion of 127°, MEPS of 94 and DASH of 6. The 3.5mm LCP group was found to have a range of motion of 130°, MEPS of 96 and DASH of 8. No clinical difference was found between groups. A total of 9 revision surgeries after double-plate osteosynthesis were recorded including seven implant removals and two intraarticular screws. One loosening of a screw without revision surgery was reported. The 3.5mm LCP group had 9 revision surgeries including eight implant removals and one intraarticular screw.

DISCUSSION

Low-profile double-plate osteosynthesis is a safe and effective alternative treatment of olecranon fractures. Subjective and objective clinical outcome measures revealed a low complication rate and excellent results. Still, implant removal due to soft tissue irritation remains an issue. These findings were comparable to common dorsal plate osteosynthesis.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Use of an Additional Nonlocking Screw in Olecranon Fracture Osteosynthesis Changes Failure Mechanism

Hardware-related complications can occur when plate fixation is used to stabilize osteoporotic fractures involving the olecranon. The use of an additional nonlocking screw, placed retrograde into the proximal fracture segment, may improve stability under load. The purpose of this study was to conduct a biomechanical comparison of olecranon repair constructs with and without this additional retrograde screw. Nine matched pairs of elderly fresh-frozen cadaveric upper extremities were used. Two-part olecranon fractures were modeled, and fracture stabilization was performed. Olecranon plates were implanted either with the standard surgical technique (CTRL) or with an additional retrograde screw (EXPT). Dynamic extensions of increasingly loaded forearms were performed, and comparisons of sustained cycles, maximum load, and total work were made. Relative motion of bone segments was tracked, and modes of failure were assessed. Seventy-eight percent of specimens from the CTRL group failed due to relative fragment displacement exceeding 3 mm, while 78% of EXPT specimens failed due to instantaneous catastrophic failure. There were no significant differences in terms of number of survived cycles, maximum load, or work performed between the groups. The addition of a retrograde screw in this plating technique changes the failure mode from fracture displacement to catastrophic failure. The use of a 3.5-mm retrograde screw in the relatively small proximal ulnar fragment should be avoided, but screws with a smaller diameter may still have potential to improve fixation. Further biomechanical and clinical research is necessary to improve strategies for plate fixation of olecranon fractures in the elderly population. [Orthopedics. 2019; 42(1):e74-e80.].