Lasso plate - An original implant for fixation of type I and II Regan-Morrey coronoid fractures

Biomechanical evaluation of the modified lasso technique

BACKGROUND

The Terrible Triad of the elbow is a constellation of elbow dislocation, radial head fracture and coronoid process fracture. A common type of coronoid fracture documented with this triad is type II Regan-Morrey coronoid fractures. The preferred fixation method for this fracture type is the lasso technique, medial-lateral tunnel orientation being the traditional approach. Considering elbow anatomy, we saw an opportunity to potentially improve fixation by altering the suture lasso tunnel orientation to a proximal-distal orientation.

HYPOTHESIS

Two tunnels in the proximal-distal direction would result in greater biomechanical stability as compared to the traditional lasso technique.

MATERIAL AND METHODS

A type 2 Regan-Morrey fracture was created in 12 fresh frozen cadaveric elbows at 50% of the coronoid height using an oscillating saw. The humero-ulnar joint was placed in 0 degrees flexion then loaded at a rate of 10mm/min to failure.

RESULTS

The control technique (medio-lateral tunnels) showed failure load of 150±81N that was not significantly different (p=0.825) than the 134±116N measured for the modified technique (distal-proximal tunnels). The portion of the load-displacement curve used to calculate stiffness was linear (R^2=0.94±0.04) with determination coefficients that did not differ between the two groups (p=0.351). For stiffness, we measured 17±13N/mm and 14±12N/mm respectively for control and modified techniques that did not result in a significant difference (p=0.674).

CONCLUSION

In this attempt to improve the shortcomings of the lasso technique, we found that changing from medio-lateral to proximal-distal drilling directions did not result in an appreciable biomechanical benefit.

LEVEL OF EVIDENCE

Basic science study; Biomechanics.

Three-dimensional quantitative study and functional outcome analysis of coronoid fracture in different elbow injury patterns

BACKGROUND

Coronoid fractures are often part of a complex fracture-dislocation of the elbow. For an optimum prognosis, it is important to understand the characteristics of coronoid fractures in different elbow injury patterns. Significant differences in these characteristics have been observed in various studies, but these previous studies have suffered from limitations, such as insufficient quantification and unknown prognostic differences among different injury patterns. Therefore, we aimed to quantitatively analyze coronoid fracture characteristics and functional outcomes in different elbow injury patterns using three-dimensional computed tomography.

METHODS

All patients with coronoid fractures surgically treated at our hospital between January and December 2017 were categorized into 3 groups according to elbow injury pattern: posterolateral rotational instability (PLRI), varus posteromedial rotational instability (VPMRI), and olecranon fracture-dislocation (OFD). 3D models were reconstructed using Mimics 17.0, and the total volume and number of coronoid fragments were measured. The coronoid process edge was classified into different anatomical regions, and each region was assigned a number to quantify the distribution of fracture lines. At the last follow-up, the range of motion, visual analog scale, Mayo Elbow Performance Score, complications and reoperations were recorded.

RESULTS

The 92 patients enrolled had an average age of 42 ± 15 years and a male-to-female ratio of 66:26. The median total volume in PLRI patients was less than that in VPMRI patients [431 (132, 818) mm3 vs. 1125 (746, 1421) mm3, adjusted P < .001] and OFD patients [431 (132, 818) mm3 vs. 2565 (381, 4076) mm3, adjusted P = .001]. The median number of coronoid fragments in PLRI patients was also less than that in VPMRI patients [1 (1, 2) vs. 2 (1, 3), adjusted P = .043]. Most of the PCFL-Rs (79%) were located around the volar edge of the lesser sigmoid notch. Compared with that of PLRI, the PCFL-Us of the VPMRI and OFD tended to be located on the more ulnodorsal side of the coronoid process edge. The median ROM [110 (90, 133), P = .001] and the median Mayo Elbow Performance Score [85 (68, 95), P = .038] of patients with OFD were significantly less than those of patients with the other 2 patterns. The incidence of elbow stiffness (56%, 5/9, P = .001) and implant-related irritation (44%, 4/9, P < .001) in the OFD group was significantly higher than that in the other 2 groups.

CONCLUSION

Coronoid fractures differ significantly in fragment volume, comminution severity, and fracture line distribution among different elbow injury patterns. OFD has the worst functional outcomes among complex elbow injury patterns.

A novel and superior Lasso-plate technique in treatment for coronoid process fracture in the terrible triad of elbow

The treatment of ulna coronal process fractures in the terrible triad of elbow, especially type I and II Regan-Morrey coronoid fractures, still have been controversial. The purpose of this retrospective study was to evaluate the novel Lasso-plate technique to have a more reliable fixation and a well clinical outcomes for type I and II Regan-Morrey coronoid fractures in a terrible triad of the elbow (TTE). Patients with simple TTE, closed fracture, aged > 18 years, duration of injury < 2 weeks, type I and II Regan-Morrey coronoid process fracture fixed by the Lasso-plate technique or ORIF were enrolled in the study. Total 144 patients with type I and II Regan-Morrey coronoid fracture in TTE were included in the Lasso-plate group or ORIF (open reduction and internal fixation) group in the Xi'an Honghui Hospital from January 2017 to December 2020. Eighty-six patients in Lasso-plate group underwent surgery using a novel Lasso-plate technique. And other 58 patients in ORIF group underwent surgery using ORIF. The data of two groups, including the X-ray films, Computed tomography (CT), the range of elbow motion, Mayo Elbow Performance Score (MEPS) and the surgical complications, were extracted from the hospital's patient records. All patients in both groups were followed up at least 12 months. The mean operation time (88.2 ± 12.3 min) in Lasso-plate group is shorter than that of ORIF group (109.1 ± 13.0 min). There was one patient with injury of deep branch of radial nerve and one patient with superficial surgical incision infection in Lasso-plate group. There were two patients with surgical incision infection in ORIF group. There were three heterotopic ossifications in Lasso-plate group and eight heterotopic ossifications in ORIF group. There were 5 elbow joints stiffness in Lasso-plate group and 12 in ORIF group. At 12 months follow up, the mean range of flexion-extension motion in Lasso-plate group was 122.9° ± 13.4° versus 113.2° ± 18.1° in ORIF group (p < 0.01), the mean 89.7 ± 5.6 MEPS in Lasso-plate group versus mean 83.7 ± 6.1 MEPSin ORIF group. The fixation of coronoid process fracture in TTE by the Lasso-plate technique, especially type I and II Regan-Morrey coronoid fracture, could be easier to master and operate, could provide the sufficient stability of elbow joint to enable early functional exercise, along with a better clinical outcome, a lower surgical complication. For the treatment of TTE, we recommend the fixation of type I and II Regan-Morrey coronoid fracture with the Lasso-plate technique, which would result in a better clinical outcome.

Comparison of buttress plate and cannulated screw in the treatment of anteromedial coronoid fracture with elbow posteromedial rotatory instability

PURPOSE

The purpose of this study is to compare the effect of buttress plate and cannulated screw in the treatment of anteromedial coronoid fracture with posteromedial rotatory instability (PMRI).

METHODS

We retrospectively evaluated patients who were diagnosed with O'Driscoll type 2 fractures combined with elbow posteromedial rotatory instability and underwent surgery for anteromedial coronoid fracture between August 2014 and March 2019. They were divided into buttress plate (n=16) and cannulated screw (n=11) groups. The elbow range of motion, visual analog scale (VAS), Mayo elbow performance score (MEPS), and disabilities of the arm, shoulder, and hand score (DASH) were used for clinical outcome assessment.

RESULT

There were no significant differences in clinical outcomes. However, the surgical time was significantly shorter in cannulated screw group (85.45±4.156) compared to the buttress plate group (93.81±8.863, P=0.008), and the surgical time was associated with internal fixation (P=0.008).

CONCLUSION

Although there was selection of cases in that small fragments were treated with buttress plate and large fragments with cannulated screw, the buttress plate and cannulated screw have comparable functional outcomes on fixation of the anteromedial coronoid fracture with elbow PMRI. The fixation of the anteromedial coronoid fracture with large fragments using the cannulated screw has a shorter operation time.

The Novel Hooked Kirschner Wire Technique for Ulna Coronoid Process Fractures

Background

The aim of this study was to introduce a novel technique to improve the ease of fixing of even small fragments of the coronoid process and report the clinical outcomes of this method.

Methods

Forty-nine patients with ulnar coronoid process fractures fixed using the hooked Kirschner wire (K-wire) technique at our hospital from 2007 to 2019 were reviewed. Radiological features and fracture union were assessed using simple radiographs. Functional outcomes of the treated elbows were evaluated at the final follow-up visit using the Mayo Elbow Performance Score (MEPS).

Results

All patients were examined at a mean follow-up of 17.7 months (range, 6-62 months). We observed bony union in patients at a mean of 10.9 weeks (range, 6-22 weeks). The mean flexion and extension ranges of the elbow were 132.0° (range, 106° -151°) and 4.5° (range, -20° to 30°), respectively. The mean pronation and supination ranges of the forearm were 81.1° (range, 60°-90°) and 88.3° (range, 60°-120°), respectively. The mean arc of the elbow was 127.4° (range, 78°-160°). All patients were evaluated using the MEPS at the final follow-up visit, with a mean score of 96.9 points (range, 80-100 points). One case of coronoid nonunion was observed and re-fixation was performed. One case of infection was observed and also treated with additional surgery. Three patients complained of ulnar nerve symptoms and 1 patient underwent surgical release for tardy ulnar nerve palsy.

Conclusions

Despite its limitations, the hooked K-wire technique was a useful method for even smaller coronoid process fractures. K-wires were also a useful temporary intraoperative fixation method and could provide permanent fixation.

Plate fixation through an anterior approach for coronoid process fractures: A retrospective case series and a literature review

Coronoid process fractures of the ulna are difficult to treat, and are associated with stiffness, recurrent instability, and pain. Hence, treatment of coronoid process fractures are challenging for surgeons. The purpose of this study was to report the clinical outcomes of an anterior surgical approach associated with plate fixation for Regan and Morrey type II or type III fractures of the coronoid process.We evaluated 16 consecutive patients who underwent surgical treatment for fracture of the coronoid process of the ulna from March 2012 to July 2016. Ten patients had a type II fracture, and 6 patients had a type III fracture. All patients underwent surgical treatment for coronoid process fracture through an anterior approach. While preserving the neurovascular structure, all fractures were treated with buttress plate fixation, maintaining the gap between brachial artery and median nerve. Each patient was treated with concentric reduction of both the ulnotrochlear and the radiocapitellar articulations, without any evidence of elbow instability, except 1 case, who showed some medial instability.At the final follow-up, solid osseous union was confirmed for all coronoid fractures. The average time to radiologic union was 16.3 weeks. The mean flexion-extension arc was 124.25 ± 12.12 degree, with a mean flexion contracture of 8.25 ± 4.36 degree, and further flexion of 132.5 ± 9.31 degree. The mean forearm rotation arc was 167.81 ± 10.49 degree. Fifteen patients achieved a functional arc of motion. The mean Mayo elbow performance score was 92.1 points, with 12 excellent cases and 4 good cases.Coronoid process fractures of the ulna can be treated successfully with plate fixation through an anterior surgical approach, which allows for accurate reduction and rigid internal fixation and early functional exercise, resulting in a reasonable outcome.