Ulnar Osteotomy Research Articles

Management of Neglected Pediatric Monteggia Fracture-Dislocation: A Case Report and Literature Review

Background: Missed or neglected Monteggia lesions are defined as classical fracture-dislocation presenting at least four weeks after injury. This injury in children is often challenging to treat and requires complex methods to achieve optimal results. Case Report: We report a 6-year-old girl with a 2-month-old neglected Bado type-I Monteggia fracture-dislocation. Our patient underwent ulnar osteotomy, bone grafting, and fixation with a semi-tubular plate along with open radial head reduction. Although the patient experienced wound complications at the bone graft harvest site, she achieved an excellent outcome with restored functionality and range of motion (ROM). Conclusion: Neglected Monteggia injuries in pediatric patients demand multifaceted treatment approaches due to their complexity and potential for long-term functional impairment. The absence of a consensus on definitive treatment underscores the importance of early diagnosis and open reduction to enhance long-term outcomes. This case report highlights the effectiveness of ulnar osteotomy, plate fixation, and open radial head reduction in achieving favorable results.

Radial Longitudinal Deficiency: Description of a Novel Surgical Technique and Clinical Cases

Radial longitudinal deficiency III and IV present as a short upper limb, functional elbow, and wrist with severe radial and palmar angulation, where the carpus articulates with the radial and palmar edge of the ulna, allowing limited mobility in a nonfunctional position. Surgical treatment aims to correct radial angulation and flexed carpal position, often altering carpal positioning over the distal ulna and impacting wrist mobility. In addition, fixation through distal ulnar epiphysis affects its growth. Although these procedures improve appearance, functionality remains suboptimal. This study describes a novel ulnar osteotomy and extensor carpi ulnaris transfer for the correction of wrist deformity in radial longitudinal deficiency with preservation of ulnocarpal motion and epiphyseal growth. The surgical technique, indications, contraindications, and potential complications are described. Three cases with postoperative follow-ups at 36, 12, and 6 months, evaluating deformity and pre/postsurgical wrist mobility ranges, are reported. A correction was achieved in the forearm-hand angle of 71 to 88 degrees of the initial. The total range of movement, between 50 degrees and 80 degrees, was almost the same before and after the operation in the most anatomic position. In one patient, there was a residual deformity at the dorsoradial border, which showed no progression during the last 6 months of follow-up. For patients with radial longitudinal deficiency, functional outcomes with preserved mobility appear to hold greater significance. The technique described in this study enabled deformity correction while maintaining a wide range of motion. The preservation of the physis in a different orientation is an aspect that will need evaluation in long-term follow-up but offers potential treatment options in the future; due to the unknown of the secondary deformity, it is recommended that the long-term results should be awaited before adoption of this technique.

Bado type III Monteggia fractures have a high injury- and treatment-related complication rate: a single center study of 73 fractures.

Monteggia fractures can be problematic injuries. The aim of this population-based study is to evaluate the risk of complications according to the Bado types, clinical outcome, and incidence. 72 children (median age 6, range 2-11 years) with 73 Monteggia fractures treated during 2014-2022 were identified from the institutional fracture register. Timing of diagnosis, complications, and method of treatment were registered. Outcomes were assessed at mean 4 years (1-9) follow-up in 68 (94%) children. The census population (< 16 years old) in Helsinki metropolitan area during the study period was assessed. Bado types I (n = 43) and III (n = 27) comprised all but 3 of the fractures. Diagnosis was made on admission in 57, and with a 1-8-day delay in 16 children. 8 children had sustained an associated nerve injury. 35 children were treated operatively, 7 after failed closed treatment. 4 reoperations were performed, including 3 ulnar osteotomies. The risk of complications (odds ratio [OR] 4.9, 95% confidence interval [CI] 1.7-14) and closed treatment failures (OR 12.3, CI 1.3-118) was higher in Bado type III than in type I injuries. 60 children attended for clinical follow-up, all had congruent radio-humeral joints and full range of elbow and forearm motion. Mean PedsQL was 94 (72-100) and QuickDash 3 (0-13). 8 additional children reported normal elbow functions by phone. The calculated mean annual incidence of Monteggia injuries was 2.9/100,000 children. Monteggia fractures are rare (2.9/100,000 yearly). Bado type III injuries are associated with a high risk of complications.

Bone-periosteal-muscle flap for ulnar lengthening in children with congenital radial club hand

Background. Congenital radial club hand is characterized by the underdevelopment of all forearm structures. Ulnar bone shortening ranges from 24.7% to 50.0% compared to the intact limb. The aim of the study was to evaluate the outcomes of ulnar lengthening by distraction osteogenesis in patients with congenital radial club hand type IV who underwent osteotomy with the formation of a bone-periosteal-muscle flap, and to compare these results with the treatment outcomes of the patients who had standard (oblique) ulnar osteotomy. Methods. The main group consisted of 20 patients who underwent osteotomy with the formation of a bone-periosteal-muscle flap during ulnar lengthening between 2019 and 2022. The control group included 19 patients (22 forearms) who underwent oblique ulnar osteotomy between 1998 and 2018. The following indicators were evaluated: length of the regenerate, distraction time, correction period, fixation index, osteosynthesis index, and complications. Results. A lengthening of 4.1 cm was achieved (30.7% of the initial ulnar bone length). The correction of angular deformity was 71.4%. Greater correction was achieved with osteotomy in the proximal ulna. In the subgroup with proximal segment osteotomy, the distraction and osteosynthesis indices were 25.6 and 25.7 days/cm, respectively. In the mid-third osteotomy group, these indices were 42.3 and 42.6 days/cm, respectively. Complications were limited to inflammatory phenomena in 30% of cases. All patients in the main group exhibited successful regenerate formation. Thus, the bone fragment with a periosteal-muscle pedicle serves as an additional source of osteogenesis during distraction. Conclusions. This study demonstrates the appropriateness of osteotomy with the formation of a bone-periosteal-muscle flap in children with congenital radial club hand. This technique allows for greater deformity correction, a shortened regenerate formation period, and a reduction in complications.

Risk factors for unsuccessful reduction of chronic Monteggia fractures in children treated surgically.

To investigate the risk factors for unsuccessful radial head reduction (RHR) in children with chronic Monteggia fractures (CMFs) treated surgically. A total of 209 children (mean age 6.84 years (SD 2.87)), who underwent surgical treatment for CMFs between March 2015 and March 2023 at six institutions, were retrospectively reviewed. Assessed risk factors included age, sex, laterality, dislocation direction and distance, preoperative proximal radial metaphysis width, time from injury to surgery, reduction method, annular ligament reconstruction, radiocapitellar joint fixation, ulnar osteotomy, site of ulnar osteotomy, preoperative and postoperative ulnar angulation, ulnar fixation method, progressive ulnar distraction, and postoperative cast immobilization. Independent-samples t-test, chi-squared test, and logistic regression analysis were used to identify the risk factors associated with unsuccessful RHR. Redislocation occurred during surgery in 48 patients (23%), and during follow-up in 44 (21.1%). The mean follow-up of patients with successful RHR was 13.25 months (6 to 78). According to the univariable analysis, time from injury to surgery (p = 0.002) and preoperative dislocation distance (p = 0.042) were identified as potential risk factors for unsuccessful RHR. However, only time from injury to surgery (p = 0.007) was confirmed as a risk factor by logistic regression analysis. Receiver operating characteristic curve analysis and chi-squared test confirmed that a time from injury to surgery greater than 1.75 months increased the rate of unsuccessful RHR above the cutoff (p = 0.002). Time from injury to surgery is the primary independent risk factor for unsuccessful RHR in surgically treated children with CMFs, particularly in those with a time from injury to surgery of more than 1.75 months. No other factors were found to influence the incidence of unsuccessful RHR. Surgical reduction of paediatric CMFs should be performed within the first two months of injury whenever possible.

Radiocapitellar joint plasty for missed monteggia fracture with radial head deformity in children: a retrospective study.

The retrospective study reviewed the clinical and radiological outcomes of patients treated with radiocapitellar joint plasty. 10 children with missed Monteggia fracture (MMF) were reviewed. The average time from injury to operation was 20 months. The average age of children who underwent the operation was 10.5 years. 6 flat and 4 domed radial heads were included. 7 type I and 3 type III MMF were identified based on the Bado classification. All children with MMF were treated by open radial head reduction with radiocapitellar joint plasty and ulnar osteotomy (UO). The average union time was 4.9 ± 2.6 months. The average osteotomy angle to reduce the radial head was 15.7 ± 3.5°, and the average lengthening of the ulna was 8.2 ± 3.2 mm. The average preoperative flexion range of motion was 110.5 ± 9.1°, and the postoperative flexion range of motion was 138.8 ± 15.1° (p < 0.05). The average preoperative extension range of motion was 10.1 ± 3.2°, and the postoperative extension range of motion was 5.5 ± 3.3° (p < 0.05). The average preoperative pronation range of motion was 78.8 ± 8.7°, while the postoperative pronation range of motion was 81.1 ± 5.6° (p > 0.05). The average preoperative supination range of motion was 68.3 ± 9.7°, and the postoperative supination range of motion was 80.1 ± 7.8° (p < 0.05). The preoperative Kim score was 66.5 ± 10.9°, and the postoperative Kim score was 88.1 ± 12.6 (p < 0.05). The radial head was completely reduced in 9 patients, and subluxation in 1 patient. Osteoarthritis of the radiocapitellar joint was observed in 2 patients. Radiocapitellar joint plasty is effective surgical intervention for MMF with radial head deformity. It yields favorable functional outcomes while ensuring continued radial head reduction.

Effect of different ulnar osteotomies on loading of the distal radioulnar joint: a finite element analysis

BackgroundUlnar impingement syndrome is a prevalent source of ulnar carpal pain; however, there is ongoing debate regarding the specific location of shortening, the method of osteotomy, the extent of shortening, and the resulting biomechanical alterations.MethodTo investigate the biomechanical changes in the distal radioulnar joint (DRUJ) resulting from different osteotomy methods, a cadaveric specimen was dissected, and the presence of a stable DRUJ structure was confirmed. Subsequently, three-dimensional data of the specimen were obtained using a CT scan, and finite element analysis was conducted after additional processing.ResultsThe DRUJ stress did not change significantly at the metaphyseal osteotomy of 2–3 mm but increased significantly when the osteotomy length reached 5 mm. When the osteotomy was performed at the diaphysis, the DRUJ stress increased with the osteotomy length, and the increase was greater than that of metaphyseal osteotomy. Stress on the DRUJ significantly increases when the position is changed to pronation dorsi-extension. Similarly, the increase in stress in diaphyseal osteotomy was greater than that in metaphyseal osteotomy. When the model was subjected to a longitudinal load of 100 N, neither osteotomy showed a significant change in DRUJ stress at the neutral position. However, the 100 N load significantly increased stress on the DRUJ when the position was changed to pronation dorsi-extension, and the diaphyseal osteotomy significantly increased stress on the DRUJ.ConclusionsFor patients with distal oblique bundle, metaphyseal osteotomy result in a lower increase in intra-articular pressure in the DRUJ compared to diaphyseal osteotomy. However, it is crucial to note that regardless of the specific type of osteotomy employed, it is advisable to avoid a shortening length exceeding 5 mm.

A modified partial wedge-shaped metaphyseal ulnar osteotomy for the treatment of ulnar impaction syndrome with reverse oblique sigmoid notch.

We describe a modified metaphyseal ulnar osteotomy to treat ulnar impaction syndrome with a reverse oblique sigmoid notch. Based on a computational analysis of radiographs, a modified wedge metaphyseal ulnar osteotomy was devised with its apex positioned at the ulnar styloid base to avoid impaction between the sigmoid notch and ulnar head. Subsequently, nine patients with ulnar impaction syndrome and a reverse oblique sigmoid notch underwent this operation, combined with arthroscopic exploration and transosseous triangular fibrocartilage complex repair. The mean follow-up was 14 months. All patients achieved bone union within 5 weeks, with no degenerative changes being observed during the follow-up assessments. The final follow-up assessments revealed decreases in ulnar variance and in the scores for Visual Analogue Scale, Quick Disabilities of the Arm, Shoulder and Hand questionnaire and the Patient-Rated Wrist Evaluation. All patients achieved excellent or good grades on the Modified Mayo Wrist Score. This technique is effective in treating the ulnar impaction syndrome with a reverse oblique sigmoid notch.Level of evidence: IV.

Missed Monteggia Injuries in Children and Adolescents: A Treatment Algorithm.

Monteggia injuries are rare childhood injuries. In 25-50% of cases, however, they continue to be overlooked, leading to a chronic Monteggia injury. Initially, the chronic Monteggia injury is only characterized by a moderate motion deficit, which is often masked by compensatory movements. Later, however, there is a progressive valgus deformity, neuropathy of the ulnar nerve and a progressive deformity of the radial head ("mushroom deformity") with ultimately painful radiocapitellar arthrosis. In the early stages, when the radial head is not yet deformed and there is no osteoarthritis in the humeroradial joint, these injuries can be treated with reconstruction procedures. This can be achieved either by an osteotomy of the proximal ulna with or without gradual lengthening. If there is already a severe deformity of the radial head and painful osteoarthritis, only rescue procedures such as functional radial head resection or radial head resection with or without hemi-interposition arthroplasty can be used to improve mobility and, above all, to eliminate pain. In this review article, we provide an overview of the current treatment options of chronic Monteggia injury in children and adolescents and present a structured treatment algorithm depending on the chronicity and dysplastic changes.

Ulnar osteotomy between the proximal 1/3 and 1/5 provides a stable radiocapitellar joint in chronic Monteggia fracture.

The precise location of unlar osteotomy remains a subject of ongoing controversy in chronic Monteggia fracture (CMF). The purpose of this study was to analyze the influence of different levels of ulnar osteotomy on redislocation in CMF. We retrospectively reviewed 18 children following our previous series. Except the baseline characteristics and radiographic parameters such as ulnar osteotomy angle, maximum interosseous distance (MID) and proportional ulnar length (PUL), we introduced a new parameter: proportional ulnar osteotomy (PUO) which represents the quantitative level of proximal ulnar osteotomy. Based on the value of PUO, we divided it into two intervals: appropriate PUO range (1/5< PUO <1/3) and inappropriate PUO range (PUO >1/3; PUO <1/5). The relationship between these indexes and redislocation was analyzed. According to the reduction state of radial head, patients were divided in two groups: reduced (15/18) and redislocation (3/18). Only PUO range differed significantly (P=0.043) between the two groups, with a notably higher number of patients showed an osteotomy between 1/5 and 1/3 of ulna in reduced group. Combining PUO range with radiographic parameters (osteotomy angle and post-PUL) improved the accuracy and specificity over using osteotomy angle and post-PUL (accuracy, 94.44% vs. 83.33%) (specificity, 93.33% vs. 86.67%, P=0.008). This combination further enhanced the predictive capability for detecting the risk of redislocation in CMFs. Ulnar osteotomy between the proximal 1/3 and 1/5 appears to provide a much safer and more stable radiocapitellar joint in CMF.

Review and update on the management of triangular fibrocartilage complex injuries in professional athletes.

Triangular fibrocartilage complex injuries are common in amateur and professional sports. These injuries are mainly caused by acute or chronic repetitive axial loads on the wrist, particularly on the ulnar side and in association with rotations or radial/ulnar deviations. In order to treat professional athletes, a detailed specific knowledge of the pathology is needed. Moreover, the clinician should fully understand the specific and unique environment and needs of the athletes, their priorities and goals, the type of sport, the time of the season, and the position played. An early diagnosis and appropriate management with the quickest possible recovery time are the uppermost goals for both the athlete and the surgeon. A compromise between conservative vs surgical indications, athletes' needs and expectations, and financial implications should be achieved. Arthroscopic procedures should be timely planned when indicated as they could allow early diagnosis and treatment at the same time. Conservative measures are often used as first line treatment when possible. Peripheral lesions are treated by arthroscopic repair, whilst central lesions are treated by arthroscopic debridement. Further procedures (such as the Wafer procedure, ulnar osteotomies, etc.) have specific indications and great implications with regard to rehabilitation.

Navigating Isolated Post-Traumatic Radial Head Dislocation in Adolescents: A Case Report from Bangladesh Emphasizing Management Strategies

Background: Isolated anterior dislocation of the radial head is a rare orthopedic injury, oftenpresenting with distinct clinical features and requiring specialized management. We report the case of an 18-year-old female who presented to our hospital 5 months post-injury, complaining of restricted left elbow joint movement and pain following a fall from a low chair at home. Clinical examination revealed tenderness and anterior dislocation of the radial head, confirmed by radiographs showing isolated anterior dislocation without associated fractures. Closed reduction attempts failed, leading to an open reduction of radial head in combination with correction of malignant with ulnar osteotomy and reconstruction of annular ligament and radio-ulnar Kirschner wire placement for stabilization. An upper arm cast was applied with the forearm in neutral rotation for six weeks. At the 12-month follow-up, the patient exhibited a satisfactory range of motion within reference values, comprising 0-140 degrees of flexion-extension arc, 70 degrees of pronation, and 85 degrees of supination. This range aligned with standards set by the American Society for Surgery of the Hand. The patient reported no impediments in daily activities and returned to her pre-injury level of sports activity based on the Tegner scale. This case underscores the complexity of managing isolated anterior radial head dislocation, highlighting the significance of prompt diagnosis, appropriate reduction techniques, and meticulous postoperative care to achieve optimal functional outcomes. Central Medical College Journal Vol 7 No 1 January 2023 Page: 57-62

Functional Outcomes of Paediatric Missed Monteggia Fractures Managed with Angulation Distraction Osteotomy of Ulna - A Case Series

Functional Outcomes of Paediatric Missed Monteggia Fractures Managed with Angulation Distraction Osteotomy of Ulna - A Case Series

Step-cut, biplanar, elongation and angulation ulnar osteotomy with annular ligament reconstruction in neglected Monteggia fracture dislocation in children: a retrospective study

Monteggia fracture dislocation is an infrequent injury in children, with around 20-50% cases being missed on initial consultation; leading to their chronic and neglected forms leading to number of complications; thus justifying their operative management. Various treatment modalities have been suggested in the literature for these neglected injuries. A retrospective study of 7 patients (5 males and 2 females), with mean age of 9.58 years (7-14 years); with neglected Monteggia fracture dislocation undergoing corrective reconstructive surgery in the form of elongation and angulation proximal ulnar osteotomy with radial head reduction combined with annular ligament reconstruction was conducted and was then evaluated clinically and functionally using Mayo Elbow Performance Index (MEPI) score; and radiographicaly were graded as good, moderate or poor. The mean interval from time of injury to the time to corrective surgery was 10.58 weeks (range 6-16 weeks). The mean improvement in the post operative MEPI score was 23.57. The mean improvement in the post operative flexion-extension arc was 28.57˚, while that in the supination-pronation arc was 20.72˚. We concluded that Step-cut, biplanar, elongation and angulation proximal ulnar osteotomy with additional reinforcement in the form of annular ligament reconstruction is an effective technique to treat neglected Monteggia fracture dislocations in children; having excellent clinical, functional and radiological outcomes.

Influence of oblique proximal ulnar osteotomy on humeral intracondylar fissures in 35 spaniel breed dogs.

To investigate the effects of oblique proximal ulnar osteotomy (PUO) on the healing of humeral intracondylar fissure (HIF) in spaniel breed dogs. Clinical retrospective study. A total of 51 elbows from 35 spaniel dogs. An oblique PUO was performed in dogs diagnosed with HIF. The degree of healing of HIF was subjectively and objectively assessed on preoperative and long-term follow-up CT imaging. Objective assessment was performed by measuring the bone density in Hounsfield units (HU) of a rectangular region of interest (ROI) encompassing the entire hypoattenuated humeral fissure. Major and minor complications were recorded. A total of 24 partial and 27 complete HIFs were diagnosed. The follow-up CT scan was performed at a median 18.5 months (range 10-49 months). Subjective assessment confirmed partial or complete healing of the HIF in 41 elbows (80.3%). Objective assessment confirmed a difference in mean HU of the HIF's ROI between preoperative (HU 640) and last follow-up CT images (HU 835) (p = .001). Young dogs (<14 months) had the highest increase in HU of the HIF's ROI. Major complications occurred in five dogs (6 limbs) of which four were related to the lack of healing of the fissure (7.8%). Oblique PUO resulted in partial or complete healing of HIF and pain resolution in the majority of dogs. This study introduces an innovative approach to achieve healing of the HIF in the dog, which may help reduce the high complication rate traditionally associated with the use of transcondylar screws.

Restoring Wrist Harmony: A Case Report of Ulnar Osteotomy for Correcting the Radius Malunion

Restoring Wrist Harmony: A Case Report of Ulnar Osteotomy for Correcting the Radius Malunion

Lower body weight and increasing age are significant risk factors for complications following bi-oblique proximal ulnar osteotomy in dogs.

To report and evaluate the risk factors for complications following bi-oblique proximal ulnar osteotomy (PUO) in dogs. 82 client-owned dogs (93 limbs). Clinical records of dogs treated with bi-oblique PUO over a 5-year period were reviewed. Postoperative radiographs were analyzed, and osteotomy location and angles were recorded; follow-up radiographs were reviewed to assess the degree of osteotomy healing. Complications were classified as minor, major, and catastrophic. Logistic regression analysis was performed to investigate possible associations between the predictor variables and occurrence of complications. 82 dogs (93 limbs) were included. Postoperative complications were documented in 39 limbs (13 major and 26 minor). The most common major complication was osteotomy nonunion (8 limbs), while the most common minor complication was delayed union (21 limbs). Statistical analysis revealed that lower body weight (P = .01) and older age (P = .04) were significantly associated with the development of postoperative complications. In this study, lighter and older dogs were more likely to develop complications following bi-oblique proximal ulnar osteotomy. We did not identify an association between osteotomy angle and location on complication rate. Careful patient selection is therefore required to reduce the incidence of postoperative complications after bi-oblique PUO.

Letter to the Editor regarding Liu et al.: 'Ulnar osteotomy and monolateral external fixator for the treatment of chronic Monteggia fractures in children: comparison between gradual and acute radial head reduction'.

Letter to the Editor regarding Liu et al.: 'Ulnar osteotomy and monolateral external fixator for the treatment of chronic Monteggia fractures in children: comparison between gradual and acute radial head reduction'.

Evaluating Outcome of Surgical Centralization for Radial Club Hand in Children

Background: Various types of osteotomy have been proposed to treat Radial club hand. We reviewed the results of Ulnar osteotomy, Centralization, and tendon transfer. Methods: Between 2000 and 2011, we treated 32 cases of Radial club hand with two Variants Variation 1 (n= 23): ulnar osteotomy; Variation 2 (n=9): without osteotomy; There were 23 patients. Male 10 and Female: 13. Unilateral: 14. Bilateral: 9. Mean age at Operation: 33 months and Follow Up: 56 months. We compared Wrist-Forearm, Hand-Forearm angles before and after surgery, range of motion for all patients. Results: Surgical Centralization on all patients, and Ulnar Osteotomy on 23 forearms. The Patients was Operated according to separated two Variants; there were 23 Variant 1, mean Ulnar bow: 38.68° ±3.583 (33.6° – 45.2°); and there were 9 Variant 2. mean Ulnar bow: 28.15° ± 3.176 (25.7°—28.4°)without ulnar osteotomy. There were 14 patients with unilateral: 8 (57.1%) in V1, and 6 (42.9%) in V2. There were 9 patients with bilateral (18 radial club hand): 15 (83.3%) in V1, and 3 (16.7%) in V2. Compared results on V1 and V 2 with P-values are not significant. Conclusion: Centralization and Ulnar osteotomy technique for operative treatment of the radial club hand is presented. The improved mechanical forces are further stabilized by transposition of the radial wrist extensor and flexor; this favors a better muscle balance.

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.