The influence of gravity on the unstable elbow

Complex elbow fracture-dislocations- what factors are associated with a poor post-operative outcome?

PURPOSE

Despite standardized treatment algorithms, patients with complex elbow fracture-dislocation frequently suffer from poor post-operative elbow function leading to reduced quality of life. Up to now, there is no valuable data regarding risk factors that lead to poor post-operative outcome after surgical reconstruction of complex elbow fracture-dislocations.

METHODS

From 06/2010 to 12/2020 134 patients (51.3 ± 15.1 years, 44% women) undergoing surgical treatment of complex elbow fracture-dislocations could be included in this study. Follow-up period was 4.4 years (SD 2.5). All patients were clinically evaluated for elbow movement, elbow stability and common elbow scores (MEPS, OES, DASH-Score). Potential risk factors for poor post-operative outcome were identified using bi- and multivariate analyses.

RESULTS

Overall good post-operative outcome has been achieved, mean MEPS was 88.8 ± 17.6. Post-operative complications occurred in 31.3% of the cases, while 25.4% required surgical revision. Patients with transolecranon dislocation fractures showed the significantly worst functional outcomes (p = 0.01). In addition, it has been shown that a patient's age of more than 70 years (OR = 10, p = 0.003) and a BMI of more than 35 kg/m2 (OR = 7.6, p = 0.004) are independent risk factors for a poor post-operative outcome. In contrast, gender and time to surgery showed no significant influence on post-operative outcome.

CONCLUSION

In most cases, good post-operative functional results can be achieved using standardized treatment protocols. However, complication and revision rates remain high. Patients older than 70 years of age or with a BMI over 35 kg/m2 are at risk for an inferior outcome and require close follow-up monitoring.

The use of hinged elbow orthosis following surgical management of terrible triad injuries of the elbow

PURPOSE

To determine outcomes following surgical management of terrible triad injuries in patients treated with and without a hinged elbow orthosis (HEO) in the post-operative setting.

METHODS

This study was a retrospective review of 41 patients who underwent surgical treatment of terrible triad injuries including radial head fracture, coronoid fracture, and ulnohumeral dislocation between 2008 and 2023 with at least 10-week follow-up.

RESULTS

Nineteen patients were treated post-operatively without HEO, and 22 patients were treated with HEO. There were no differences in range of motion (ROM) between patients treated with and without HEO in final flexion-extension arc (118.4° no HEO, 114.6° HEO, p = 0.59) or pronation-supination arc (147.8° no HEO, 141.4° HEO, p = 0.27). Five patients treated without HEO and one patient treated with HEO returned to the operating room for stiffness (26%, 5%, p = 0.08). QuickDASH scores were similar between groups (p = 0.69).

CONCLUSIONS

This study found no difference in post-operative ROM, complications, or QuickDASH scores in patients treated post-operatively with or without HEO. Based on these results, we cannot determine whether the use of HEO adds additional stability to the elbow while initiating ROM exercises post-operatively.

Stabilizing effect of an elbow orthosis with an adjustable hinge axis after lateral collateral ligament injury: A biomechanical study

Background

Current commercial elbow braces have a straight hinge that does not account for the native carrying angle of the elbow. The objective of this study was to determine the effectiveness of a custom-designed hinged elbow orthosis (HEO) with variable valgus angulations in stabilizing a lateral collateral ligament (LCL) deficient elbow.

Methods

Eight cadaveric upper extremities were mounted in an elbow motion simulator in the abducted varus gravity-loaded position. The specimens were examined before and after simulated LCL injury and then with the addition of the custom-designed HEO with 0°, 10°, and 20° of valgus angulation. Kinematic data were recorded using an electromagnetic tracking system.

Results

The LCL injured state with or without the brace resulted in significant increases in varus angulation of the elbow compared to the intact state in both pronation and supination (P < 0.05). There were no significant differences in varus-valgus angulation or ulnohumeral rotation between any of the brace angles and the LCL injured state with the forearm pronated and supinated.

Discussion

The custom-designed HEO did not provide any additional stability to the LCL injured elbow. The varus arm position should be avoided during the rehabilitation of an LCL injured elbow even when an HEO is used.

Mid-term outcome following radial head arthroplasty in acute trauma: risk factors for poor outcome

BACKGROUND

The aims of this study were to evaluate the outcomes of a single type of radial head implant in a large cohort of patients at mid-term follow-up and to determine the associated risk factors for inferior functional outcomes.

METHODS

We performed a retrospective follow-up assessment of 65 patients (33 women and 32 men; mean age, 53.3 years [range, 22-81 years]) who underwent radial head arthroplasty (RHA) for acute trauma between 2012 and 2018, after a minimum follow-up period of 3 years. The Mayo Elbow Performance Score, Oxford Elbow Score, Disabilities of the Arm, Shoulder and Hand score, and Mayo Modified Wrist Score were evaluated, and all available radiographs were analyzed. All complications and revision procedures were assessed. Bivariate and multivariate regression analyses were performed to identify potential risk factors for a poor outcome following RHA.

RESULTS

After an average follow-up period of 4.1 years (range, 3-9.4 years), the mean Mayo Elbow Performance Score was 77.2 (standard deviation [SD], 18.9); mean Oxford Elbow Score, 32.0 (SD, 10.6); mean Mayo Modified Wrist Score, 74.6 (SD, 13.7); and mean Disabilities of the Arm, Shoulder and Hand score, 29.0 (SD, 21.2). Average range of motion measured 10° (SD, 15°) in extension, 125° (SD, 14°) in flexion, 81° (SD, 14°) in pronation, and 63° (SD, 24°) in supination. The overall complication and reoperation rates were 38.5% and 30.8%, respectively, with severe elbow stiffness being the most common reason for revision. Patient age >50 years, the use of an external fixator, the presence of accompanying medial collateral ligament injuries, and the development of higher-grade osteoarthritis were associated with a poor outcome.

CONCLUSION

Satisfactory medium-term outcomes can be achieved using a monopolar, long-stemmed RHA in patients with acute trauma. However, complication and revision rates are high, frequently leading to inferior outcome scores. Additionally, a higher patient age, the use of an external fixator, the presence of accompanying medial collateral ligament injuries, and the occurrence of higher-grade osteoarthritis were associated with a poor outcome; these factors should raise awareness by the treating trauma surgeon.

Improved Understanding of Traumatic Complex Elbow Instability

Recent advancements in surgical treatment have improved clinical results in complex traumatic elbow injury. There is increasing recognition that conservative treatment and inadequate surgical fixation carry high risk of substantial morbidity in many of these cases. Recent literature displays improved outcomes in complex elbow instability, in part, because of a more complete comprehension of the injury patterns and fixation methods. Prompt surgical management with stable internal fixation, which permits immediate postoperative mobilization, has been a consistent variable across the reports leading to more satisfactory outcomes. This applies to both acute and chronic cases.

Prospective clinical results of an additive ligament bracing for stabilizing simple and complex elbow instabilities

INTRODUCTION

Ligament bracing augments ligament repair using a non-absorbable suture tape. Although biomechanically an increase in primary stability has been proven, there is a lack of clinical evidence. Purpose of this study was to evaluate clinical results of patients treated with ligament bracing due to primary elbow instability, including an analysis of complications. Furthermore, clinical results for patients treated with and without early functional mobilization were compared.

MATERIALS AND METHODS

This prospective case-series evaluated clinical and functional results from patients treated with ligament bracing due to primary elbow instability. Clinical outcome measures were range of motion (ROM) as well as objective and subjective elbow scores [Mayo Elbow Performance Score (MEPS); Disabilities of Arm, Shoulder and Hand Score (DASH score)]. Stability was evaluated sonographically by humero-radial gapping under varus stress.

RESULTS

This study involved 34 patients treated with ligament bracing. After a mean follow-up of 12.9 months ROM was 112° ± 29, MEPS 88 ± 13 points, DASH 91 ± 11 points, and 84% were satisfied with their result. Lateral joint gapping was 2.4 mm. No significant difference was observed regarding a postoperative mobilization with and without limitations. Most common complication after ligament bracing was elbow stiffness including heterotopic ossifications in four patients (12%).

CONCLUSION

Operatively treated elbow instability with additional ligament bracing results in good clinical outcomes with high patient satisfaction and recovery of elbow stability. The high primary stability of the ligament bracing allows early functional mobilization without bracing, which facilitates postoperative rehabilitation. Elbow stiffness with heterotopic ossification seems to be a potential complication. Furthermore, the optimal tensioning of the ligament bracing remains challenging, including the risk of an over tensioning.

LEVEL OF EVIDENCE

III.

Biomechanical comparison of elbow stability constructs

BACKGROUND

Despite surgical stabilization of complex elbow trauma, additional fixation to maintain joint congruity and stability may be required. Multiple biomechanical constructs include a static external fixator (SEF), a hinged external fixator (HEF), an internal joint stabilizer (IJS), and a hinged elbow orthosis (HEO). The optimal adjunct fixation to surgical reduction is yet to be determined.

METHODS

Eight matched cadaveric upper extremities were tested in a biomechanical model. Anteroposterior stress radiographs were obtained of the elbow in full supination at 0° and 45° of elbow flexion with the weight of the hand serving as a varus load as the baseline. A 360° capsuloligamentous soft-tissue release was performed around the elbow. The biomechanical constructs were applied in the same sequential order: SEF, HEF, IJS, and HEO. For each construct, 0 kg (0-lb) and 2.3 kg (5-lb) of weight were applied to the distal arm. At both weights, radiographs were obtained with the elbow at 0° and 45° of flexion, with subsequent measurement of displacement, congruence at the ulnohumeral joint, and the ulnohumeral opening angle. Statistical analysis was performed to quantify the strength and stability of each construct.

RESULTS

Compared with the control group at 0° with and without 2.3 kg (5-lb) of varus force and at 45° with and without 2.3 kg (5-lb) of varus force, no difference was noted in the medial ulnohumeral joint space, lateral ulnohumeral joint space, or ulnohumeral opening angle between the SEF, HEF, and IJS. The gap change after exertion of a 2.3-kg (5-lb) force between the control condition and application of each construct demonstrated no difference between the SEF, HEF, and IJS. Comparison among destabilized elbows showed no significant difference between the SEF, HEF, and IJS. The HEO catastrophically failed in each position at 0 kg (0-lb) of weight.

CONCLUSION

The SEF, HEF, and IJS are neither superior nor inferior at maintaining elbow congruity with the weight of the arm and 2.3 kg (5-lb) of varus stress. The HEO did not provide additional stability to the unstable elbow.

Overhead arm positioning in the rehabilitation of elbow dislocations: An in vitro biomechanical study

STUDY DESIGN

In vitro biomechanical study.

INTRODUCTION

Elbow stiffness is a common complication following elbow dislocation. Overhead exercises have been proposed to initiate early motion to reduce stiffness through employing gravity to stabilize the elbow. The implications of this position with regard to elbow kinematics after dislocation have not been reported.

PURPOSE OF THE STUDY

To determine the influence of the overhead position on elbow stability following combined medial and lateral collateral ligament (MCL and LCL) injuries.

METHODS

Passive and simulated active extension were performed on 11 cadaveric elbows with the arm in the overhead, dependent, and horizontal positions and with the forearm in pronation, neutral, and supination. Internal-external rotation (IER) and varus-valgus angulation (VVA) of the ulnohumeral joint were assessed for the intact elbow and after simulated MCL-LCL injury. Repeated-measures analyses of variance were conducted to analyze the effects of elbow state, arm position, forearm rotation, and extension angle.

RESULTS

During passive extension with the arm overhead, the pronated position resulted in more internal rotation than supination (-2.6 ± 0.7°, P = .03). There was no effect of forearm rotation on VVA. The overhead position increased internal rotation relative to the dependent position when the forearm was neutral (-8.5 ± 2.5°, P = .04) and relative to the horizontal position when the forearm was supinated (-12.7 ± 2.2°, P= .02). During active extension, pronation increased valgus angle compared to the neutral (+1.2 ± 0.3°, P= .04) and supinated (+1.5 ± 0.4°, P= .03) positions, but did not affect IER. There was no difference between active and passive motion with the arm overhead (P > .05).

DISCUSSION

Movement of the injured elbow in the overhead position most closely replicated kinematics of the intact elbow compared to the other arm positions.

CONCLUSIONS

Overhead elbow extension results in similar kinematics between an intact elbow and an elbow with MCL and LCL tears. As such, therapists might consider early motion in this position to reduce the risk of elbow stiffness after dislocation.

Rehabilitation of Elbow Instability

The elbow is the second most commonly dislocated major joint in adults with estimated incidence of 5 dislocations per 100,000 persons per year. A comprehensive understanding of elbow anatomy and biomechanics is essential to optimize rehabilitation of elbow injuries. This allows for implementation of a systematic therapy program that encourages early mobilization within a safe arc of motion while maintaining joint stability. To optimize outcomes, close communication between surgeon and therapist is necessary to allow for implementation of an individualized rehabilitation program. This article reviews key concepts that enable the clinician to apply an evidence-informed approach when managing elbow instability.

The Effectiveness of a Hinged Elbow Orthosis in Medial Collateral Ligament Injuries: An In Vitro Biomechanical Study

BACKGROUND

Medial collateral ligament (MCL) injuries are common after elbow trauma and in overhead throwing athletes. A hinged elbow orthosis (HEO) is often used to protect the elbow from valgus stress early after injury and during early return to play. However, there is minimal evidence regarding the efficacy of these orthoses in controlling instability and their influence on long-term clinical outcomes.

PURPOSE

(1) To quantify the effect of an HEO on elbow stability after simulated MCL injury. (2) To determine whether arm position, forearm rotation, and muscle activation influence the effectiveness of an HEO.

STUDY DESIGN

Controlled laboratory study.

METHODS

Seven cadaveric upper extremity specimens were tested in a custom simulator that enabled elbow motion via computer-controlled actuators and motors attached to relevant tendons. Specimens were examined in 2 arm positions (dependent, valgus) and 2 forearm positions (pronation, supination) during passive and simulated active elbow flexion while unbraced and then while braced with an HEO. Testing was performed in intact elbows and repeated after simulated MCL injury. An electromagnetic tracking device measured valgus angulation as an indicator of elbow stability.

RESULTS

When the arm was dependent, the HEO increased valgus angle with the forearm in pronation (+1.0°± 0.2°, P = .003) and supination (+1.5°± 0.0°, P = .006) during active motion. It had no significant effect on elbow stability during passive motion. In the valgus position, the HEO had no effect on elbow stability during passive or active motion in pronation and supination. With the arm in the valgus position with the HEO, muscle activation reduced instability during pronation (-10.3°± 2.5°, P = .006) but not supination (P = .61).

CONCLUSION

In this in vitro study, this HEO did not enhance mechanical stability when the arm was in the valgus and dependent positions after MCL injury.

CLINICAL RELEVANCE

After MCL injury, an HEO likely does not provide mechanical elbow stability during rehabilitative exercises or when the elbow is subjected to valgus stress such as occurs during throwing.

The effect of torsional moments on the posterolateral rotatory stability of a lateral ligament deficient elbow: An in vitro biomechanical investigation

BACKGROUND

Clinical tests for posterolateral rotatory instability of the elbow apply external torsional moments to the forearm; however, biomechanical studies of lateral collateral ligament injuries and their surgical repair, reconstruction and rehabilitation have primarily relied on varus gravity loading to quantify instability. The aim of this investigation was to determine the effect of torsional moments on the posterolateral rotatory instability of the lateral ligament deficient elbow.

METHODS

Six cadaveric arms were tested in an elbow motion simulator with the arm in the varus position. A threaded outrigger was inserted on the dorsal aspect of the proximal ulna to suspend 400 g, 600 g, and 800 g of weight to allow torsional moments of 0.12, 0.18, and 0.23 Nm respectively on the ulna. An injured model was created by sectioning of the common extensor origin, and the lateral collateral ligament.

FINDINGS

During simulated active flexion with the arm in varus, the injured model resulted in a significant increase in external rotation of the ulnohumeral articulation with the forearm both pronated and supinated (pronation: P = .021; supination: P = .015). The application of torsional moments to the lateral ligament deficient elbow resulted in a significant increase in the posterolateral rotatory instability of the elbow.

INTERPRETATION

This investigation demonstrates that the application of even small amounts of external torsional moments on the forearm with the arm in the varus position increases the rotational instability of the lateral ligament deficient elbow. During clinical examination for posterolateral rotatory instability and biomechanical studies of lateral ligament injury, the application of external torsion to the forearm should be considered to detect subtle instability.

LEVEL OF EVIDENCE

Basic Science Study.

In Vitro Kinematic Assessment of a Hinged Elbow Orthosis Following Lateral Collateral Ligament Injury

PURPOSE

Elbow lateral collateral ligament injuries (LCLI) are often managed with protected mobilization using a hinged elbow orthosis (HEO). The objective of this investigation was to determine the effectiveness of an HEO in stabilizing the elbow following LCLI.

METHODS

Seven fresh-frozen cadaveric upper extremity specimens were studied using a custom simulator that enabled elbow motion via computer-controlled actuators and servomotors attached to relevant tendons. Specimens were examined in 4 arm positions (dependent, overhead, horizontal, and varus) and 2 forearm positions (pronation and supination) during both passive and simulated active elbow extension. Specimens were examined before and after simulated LCLI, and then with the addition of an HEO. The lateral collateral ligament, common extensor origin, and lateral elbow capsule were sectioned in the injury model. An electromagnetic tracking system measured ulnohumeral kinematics.

RESULTS

The orthosis did not change elbow stability in any arm position during active motion. Muscle activation and forearm pronation enhanced stability in the dependent, horizontal, and varus positions while the HEO was applied.

CONCLUSIONS

This HEO does not improve the in vitro stability of the elbow following simulated LCLI.

CLINICAL RELEVANCE

An HEO may be safe to use during active motion, but when a patient is not activating the muscles normally (ie, owing to fatigue or cognitive impairment) and the arm is in positions in which the weight of the orthosis might increase joint distraction, an HEO may be harmful. If an HEO is used, the forearm should be braced in pronation following LCLI.

Optimizing the rehabilitation of elbow lateral collateral ligament injuries: a biomechanical study

BACKGROUND

Elbow lateral collateral ligament (LCL) injury may arise after trauma or lateral surgical approaches. The optimal method of rehabilitating the LCL-insufficient elbow is unclear. Therapists often prescribe active motion exercises with the forearm pronated. Recently, overhead exercises have become popular as they may enable gravity to compress the elbow joint, improving stability, although this has not been proved biomechanically. This investigation aimed to quantify the effects of several variables used in LCL injury rehabilitation on elbow stability.

METHODS

Seven cadaveric specimens were tested in a custom elbow motion simulator in 3 arm positions (overhead, dependent, and varus) and 2 forearm positions (pronation and supination) during passive and simulated active elbow extension. Three injury patterns were studied (intact, LCL injury, and LCL with common extensor origin injury). An electromagnetic tracking device measured ulnohumeral kinematics.

RESULTS

Following combined LCL and common extensor origin injury, overhead positioning enhanced elbow stability relative to the other arm positions (P < .01 in pronation; P = .04 in supination). Active motion stabilized the LCL-deficient elbow in the dependent (P = .02) and varus (P < .01) positions. Pronation improved stability in the overhead (P = .05), dependent (P = .06), and varus (P < .01) positions.

CONCLUSIONS

Rehabilitation with the arm overhead improves elbow stability after LCL injury. Initiating earlier range of motion in this "safe position" might decrease elbow stiffness and allow optimal ligament healing. If exercises are done in the dependent position, active motion with forearm pronation should be encouraged. Varus arm positioning should be avoided.

Conservative management of the post-traumatic stiff elbow: a physiotherapist's perspective

Elbow stiffness is a common consequence following trauma with the management of this condition posing a challenge to therapists and surgeons alike. This paper discusses the role of conservative treatment, such as exercise and splinting, in the prevention and management of the stiff elbow, along with a review of available evidence, to justify their usage.

Rehabilitation, clinical outcome and return to sporting activities after posterolateral elbow instability: a systematic review

INTRODUCTION

The aim of this study was to systematically review the literature for rehabilitation concepts, clinical outcome and sporting performance after surgical or non-surgical treatment of Posterolateral Rotatory Instability of the elbow (PLRI).

EVIDENCE ACQUISITION

In order to identify any published clinical study reporting on rehabilitation concepts and sporting performance following surgical or non-surgical treatment of PLRI a systematic search in literature was conducted. Rehabilitation protocols were reviewed according to main rehabilitation protocol categories (bracing, range of motion [ROM], strengthening and return to sport [RTS]).

EVIDENCE SYNTHESIS

Seven articles, including 148 patients met the inclusion criteria. Lateral ulnar collateral ligament (LUCL) repair with sutures or suture anchors was reported in two studies. In four studies, treatment was an isolated graft reconstruction and in one study a repair or graft reconstruction was performed. No study reporting on conservative treatment was found. Bracing with initially limiting ROM was declared in all studies. Duration of immobilization varied from one day to six weeks postoperative. Limitation of ROM to 30° of elbow extension was reported in the majority of studies. Strengthening was allowed from six to eight weeks postoperative. Postoperative improvement in elbow range of motion was noted in all studies.

CONCLUSIONS

Although there is agreement concerning bracing and limiting ROM following PLRI surgery there is currently no consensus in the rehabilitative- and conservative treatment modalities for patients with symptomatic PLRI. The majority of surgically treated patients with PLRI regain high acceptable results but further research is needed to determine the postoperative level of performance of these athletes.

Conservative management of elbow dislocations with an overhead motion protocol

PURPOSE

To report the results of using an overhead motion protocol in 27 patients and to assess final range of motion and incidence of persistent instability in this cohort.

METHODS

A total of 27 patients were included who sustained a simple elbow dislocation and were treated nonsurgically with an overhead motion protocol designed to convert gravity from a distracting to a stabilizing force. Motion was initiated within 1 week of injury and average follow-up was 29 months. Final arc of motion and prevalence of instability were the primary outcomes measures.

RESULTS

Final mean arc of extension to flexion was from 6° to 137°, and of pronation to supination was from 87° to 86°. No recurrent instability was observed in this cohort and all patients were fully functional and without limitations at latest follow-up.

CONCLUSIONS

The overhead motion protocol was a reliable rehabilitation program after elbow dislocation that allowed for controlled early motion by placing the elbow in an inherently stable position. Prompt initiation of motion in a protected position can optimize final motion and satisfaction outcomes, and when done in a mechanically advantageous position it can potentially limit the risk of recurrent instability.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Direct repair for managing acute and chronic lateral ulnar collateral ligament disruptions

PURPOSE

Acute elbow injuries that disrupt the lateral ulnar collateral ligament and result in posterolateral rotatory instability usually require surgical treatment. The 2 technical options reported, direct repair and use of a palmaris longus tendon graft, have usually favored the use of the graft. To balance this emphasis, we report our experience with direct repair of the humeral origin in cases of trauma, whether acute, delayed, or recurrent. It was our hypothesis that because the humeral origin is the point of failure and separation, restoration of this attachment is sufficient to restore stability and durable function without the need for a graft.

METHODS

Patients with complete disruption of the posterolateral ligaments of the elbow, who were managed with direct repair to the humeral origin, were included. Patients were separated into an acute treatment group (< 30 d from injury to treatment) and a delayed treatment group (> 30 d). Mayo Elbow Performance Scores and postoperative range of motion were collected from patient records.

RESULTS

A total of 34 patients were included with a mean follow-up of 42 months. No difference was seen in Mayo Elbow Performance Scores between acute (mean, 90) or delayed treatment (mean, 89) of the lateral ulnar collateral ligament tear. No difference was seen in final elbow flexion or extension. Two patients in the acute group had failure of the direct repair requiring intervention. In the delayed group, no patients had recurrent instability.

CONCLUSIONS

No significant difference in clinical outcome or range of motion was observed after direct repair of traumatic tears of the lateral ulnar collateral ligament tear between acute and delayed treatment cohorts. Despite complete disruption of the posterolateral ligaments, direct repair of the torn ligament to its humeral origin was effective without supplemental tendon graft reconstruction irrespective of interval from injury to repair, mechanism of injury, or associated fractures.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Magnetic resonance imaging findings in acute elbow dislocation: insight into mechanism

PURPOSE

To identify with magnetic resonance imaging the location and severity of ligamentous injury after acute elbow dislocations. Based on observations that many elbow dislocations arise from an initial acute valgus load, we hypothesized that all patients would have a high-grade medial injury but not all would demonstrate injury of the lateral ligaments.

METHODS

The medial collateral ligament was subdivided into anterior bands of the anterior bundle of the medial collateral ligament (MCL) and posterior bands of the anterior bundle of the MCL, whereas the lateral collateral ligament was divided into the lateral ulnar collateral ligament and the radial collateral ligament. Distinction on magnetic resonance imaging was made between normal morphology and low-grade partial tear (< 50% of the ligament fibers), high-grade partial tear (≥ 50%), and full-thickness disruption. The site of disruption was also characterized.

RESULTS

Acute magnetic resonance imaging studies for 16 patients were included. No low-grade tears or intact evaluations of either the anterior or posterior bands of the anterior bundle of the MCL were observed; most demonstrated complete tears. The lateral ulnar collateral ligament most frequently showed complete disruption but was occasionally intact. The radial collateral ligament infrequently showed full disruption. Complete tears involving either the anterior or posterior portions of the anterior band of the MCL were significantly more common than complete tears involving the ligaments on the lateral side.

CONCLUSIONS

After elbow dislocation, complete ligamentous tears were more common on the medial versus the lateral side. Whereas the lateral ligaments were occasionally preserved, this was never observed on the medial side. These data suggest a sequence of failure starting on the medial side with subsequent variable energy dissipation laterally.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.