Ligament Injuries

MUCL injuries: diagnostic approach, non-operative vs UCLR/repair indications, and considerations for revision cases.

Overview

Surgical intervention for ligament injuries is dictated by injury grade, chronicity, and joint stability. Complete anterior cruciate ligament (ACL) tears generally yield better clinical and functional outcomes with early surgical treatment than delayed or nonsurgical care, with ACL repair demonstrating significant improvement in appropriately selected cohorts [2, 3]. Conversely, most isolated medial collateral ligament injuries are managed nonsurgically, though concomitant damage to the anterior or posterior cruciate ligaments indicates surgical management for high-grade injuries [7]. Serious lateral ligament injuries of the knee require primary surgical repair [8]. In the upper extremity, surgical repair is indicated for Grade 3 distal interphalangeal joint collateral ligament injuries lacking a definitive end point on instability testing [12], as well as for complete distal triceps ruptures in active persons and incomplete ruptures with concomitant strength loss [67].

Outcomes vary by pathology and timing. While failure of ulnar collateral ligament healing in the index finger metacarpophalangeal joint was likely due to intra-articular positioning, functional results remain excellent after surgical repair [1]. Repair of chronic ulnar collateral ligament injuries using available local tissue offers a reasonable alternative to reconstruction with durable long-term outcomes, though the majority of these patients progress to osteoarthritis [11]. Good to excellent results are reported for surgical repair of distal triceps ruptures [67]. However, the current evidence for ulnar collateral ligament injury treatment is not convincing, and expert consensus should be viewed with caution due to methodological biases [18].

The field of ligament reconstruction continues to rely on unproven assumptions and varying opinions due to a lack of well-designed randomized clinical trials proving a superior method for ACL or PCL reconstruction [21]. Future high-quality randomized studies are required for ulnar collateral ligament injury treatment [18], including trials assessing whether ACL repair is equivalent to the current gold standard of reconstruction [14]. Long-term clinical outcome studies involving larger patient numbers are also necessary to corroborate augmentation techniques for partial ACL ruptures using semitendinosus tendon in the over-the-top position [19].

Anatomy & Pathophysiology

Osseous Kinematics

Elbow kinematics deviate increasingly from the native joint with a 2 mm to a 4 mm lengthening of the radius [26]. Forearm position was not associated with the elbow varus moment, but the supination moment was associated with the elbow varus moment [36].

Ligamentous Stability and Biomechanics

Dynamic analyses using a 3-dimensional elbow model showed that none of the configurations for double-strand lateral ulnar collateral ligament reconstruction were isometric [31]. Ulnar collateral ligament reconstruction using a suspension button fixation technique reliably restored elbow kinematics to the intact state [41]. Biomechanical and clinical outcomes show that the External Joint Stabilizer – Elbow (EJS-E) via the posterior approach can restore mobility and stability in all patients with persistent instability [28]. From a biomechanical perspective, the enhancement of elbow stability with a monopolar radial head prosthesis is superior to that with a bipolar design [30]. The posterior (Boyd) approach allows better visualization of the lateral structures for repair and confers excellent stability to the elbow joint [53].

Valgus and Varus Loading

Medial elbow joint space increases under a valgus load and then decreases when a maximal grip contraction is performed [34]. Gripping does not change ulnohumeral joint space width or medial elbow tissue stiffness in the joint testing configuration and external loading conditions applied in the study [33]. Valgus torque at the elbow during baseball pitching is associated with 6 biomechanical variables of sequential body motion [37]. No kinematic or kinetic differences were noted between throwing balls and strikes [38]. Increased medial elbow torque was associated with greater ball velocity regardless of the history of medial elbow injuries in youth baseball pitchers [42]. Both elbow varus torque and swing velocity were greatest when swinging to the outside location [58]. Elbow valgus torque is poorly suited as a standalone metric for predicting injury risk due to narrow data ranges, modeling noise, and crude assumptions [45].

Postoperative Recovery and Graft Fixation

Following UCL repairs and reconstructions, elbow ROM is reliably preserved or improved with a predictable trajectory of rapid improvement within the first 2 to four months [54]. The available current evidence regarding the optimal elbow flexion angle for graft fixation possesses a high degree of fragility [47]. An improvement in isometric contraction in flexion of the elbow was observed after tenotomy of the long head of biceps tendon, but this did not reach the flexion power of the contralateral healthy arm [44].

Pitching Kinetics and Adaptations

When controlling for an individual pitcher, peak kinetics at the shoulder and elbow can be strongly predicted by ball velocity [56]. No significant relationships between adaptations in shoulder strength or ROM were related to chronic structural adaptations of the elbow in professional baseball pitchers [49]. PLRI of the elbow remains to be fully understood [57].

Classification

Ulnar Collateral Ligament (UCL): A newly proposed 6-stage MRI-based classification system utilizes the grade and location of UCL injury to distinguish between operative and nonoperative management [23]. This system demonstrates substantial to near perfect agreement among fellowship-trained observers [24]. Failure of UCL healing in the index finger metacarpophalangeal joint is likely attributable to the ligament lying within the joint [1].

Anterior Cruciate Ligament (ACL): Recent studies have clarified the natural history, complex anatomy, and functional mechanical behavior of posterior cruciate ligament injuries [5]. The incidence of noncontact ACL injuries remains high in young athletes [6]. ACL injury in male athletes likely has a multi-factorial aetiology [16].

Medial Collateral Ligament (MCL): Most isolated MCL injuries are treated nonsurgically [7]. Concomitant damage to the anterior or posterior cruciate ligaments is a common indication for surgical management of high-grade MCL injuries [7].

Lateral Ligament and Knee Instability: Serious lateral ligament injuries of the knee should be surgically treated with primary (combined) repair [8]. Collateral ligament injuries of the knee are common and challenging to treat, often occurring with cruciate ligament injuries [9]. A new intraoperative arthroscopic classification tool for posterolateral elbow instability serves as a standardized grading system for research and surgeon communication [76].

Distal Interphalangeal (DIP) Joint: Surgery is indicated only for Grade 3 DIP joint collateral ligament injuries where there is no definitive end point when tested for collateral instability due to extensive injury of the surrounding soft tissues [12].

Monteggia-like Lesions: With correct identification, classification, and understanding using CT scans followed by appropriate surgical treatment that addresses all components of the injury, good to excellent mid-term results can be achieved for Monteggia-like lesions of the elbow [17].

Pectoralis Major: A contemporary injury classification system for pectoralis major tears includes injury timing, injury location, and standardized terminology addressing tear extent to more accurately reflect the musculotendinous morphology of PM injuries [32].

Distal Biceps Tendon: Classification of partial distal biceps tendon tears may have implications for operative and non-operative management [59].

Other Considerations: Patients with ligamentous knee injuries often had multi-system injuries with resulting longer hospital stay compared to those without ligamentous knee injuries [10].

Clinical Presentation

History taking must account for high-risk demographics and mechanisms. The incidence of noncontact anterior cruciate ligament (ACL) injuries remains high in young athletes [6], with almost all skeletally immature patients sustaining these tears during sports [51]. ACL injury in male athletes likely has a multi-factorial aetiology [16]. In elite men's lacrosse, players are susceptible to a range of injuries where familiarity with common patterns aids prevention [35]. Patients with ligamentous knee injuries often present with multi-system injuries, resulting in longer hospital stays compared to those without such injuries [10].

Inspection and palpation reveal specific patterns of acute failure. Distal biceps short head tears present acutely with a poor natural history akin to complete tears [4]. Simultaneous patellar tendon and ACL rupture is a rare condition that can be easily missed and is frequently associated with injuries of other knee structures [40]. For the thumb, ultrasound is a valuable adjunct to clinical examination in a specialist clinic, particularly for differentiating displaced from undisplaced ulnar collateral ligament tears, provided it is performed soon after presentation [46].

Stability assessment and special tests require specific diagnostic approaches. A diagnostic technique based on specific questions and three clinical tests is useful for diagnosing triquetrolunate ligament injuries before arthroscopy [13]. However, clinicians in the Emergency Department are not proficient in performing the assessment methods used for diagnosis in acute ACL injury [27]. Recent studies have shed new light on the natural history of posterior cruciate ligament (PCL) injury, as well as its complex anatomy and functional mechanical behavior [5].

Treatment decision-making relies on injury grade and concomitant damage. Surgical indication: Concomitant damage to the anterior or posterior cruciate ligaments is a common indication for surgical management of high-grade medial collateral ligament injuries [7]. Nonoperative management: Most isolated medial collateral ligament injuries are treated nonsurgically [7], and most medial-sided knee injuries can be managed nonoperatively [15]. Outcomes: Clinical and functional outcomes for patients with complete ACL tears are generally better with early surgical treatment than with delayed or nonsurgical care [2]. ACL repair has demonstrated significant clinical improvement in an appropriately selected patient cohort [3]. Surgical treatment was overwhelmingly the treatment of choice for skeletally immature patients with ACL tears [51]. Controversial scenarios: Treatment strategies for severe isolated medial-sided knee injury with chronic instability and for more complex, combined-ligament injuries remain controversial [15]. Collateral ligament injuries of the knee are common and challenging to treat, often occurring with cruciate ligament injuries [9].

Red-flag patterns include specific failure mechanisms and anatomical constraints. Failure of ulnar collateral ligament healing in the index finger metacarpophalangeal joint was probably a result of the ligament lying within the joint [1].

Investigations

Plain radiography: Initial imaging requires heightened vigilance for associated physeal injuries in pediatric variants of transolecranon fracture dislocation that may not be obvious on initial radiographs [84].

MRI: A newly proposed 6-stage MRI-based classification utilizing grade and location of ulnar collateral ligament injury had substantial to near perfect agreement among and within fellowship-trained observers [23]. This reliable 6-stage MRI-based classification addressing ulnar collateral ligament tear grade and location may confer decision making between operative and nonoperative management [24]. MRI grading of ulnar collateral ligament injuries can help predict return to play and the need for surgery in professional baseball players [87]. Preoperative MRI and intraoperative assessments agreed in 80% of cases for myotendinous junction tears of the pectoralis major [82]. The agreement between preoperative MRI and intraoperative assessments for pectoralis major tears was significantly higher for complete over partial tears [82]. Ultrasound and MRI are helpful in evaluating acute brachialis rupture and monitoring its resolution [55]. Preoperative MRI could be used to exclude subtle elbow instability associated with lateral epicondylitis [91]. The clinical use of MRI in the management of patients with enthesopathy of the extensor carpi radialis longus origin merits further study [86]. There is variation in the use of MRI for lateral epicondylitis, and its use is associated with downstream effects [89]. The routine use of MRI for the diagnosis of lateral epicondylitis is low [89]. Conventional MRI technique demonstrates difficulties in the evaluation of ligaments after simple elbow dislocation as shown by weak inter- and intraobserver agreement [64].

CT: With correct identification, classification, and understanding using CT scans followed by appropriate surgical treatment addressing all injury components, good to excellent mid-term results can be achieved for Monteggia-like lesions of the elbow [17]. The nature of non-operatively treated fractures of the anteromedial facet of the coronoid process can be most reliably documented using computed tomography with three-dimensional reconstructions [77].

Ultrasound: Valgus stress ultrasound can be used as a diagnostic tool for complete medial ulnar collateral ligament ruptures in athletes [90]. Valgus stress ultrasound may not be sufficient alone for the diagnosis of partial medial ulnar collateral ligament injuries in athletes [90].

Other Considerations: A diagnostic technique based on specific questions and three clinical tests is useful for diagnosing triquetrolunate ligament injuries before arthroscopy [13]. Diagnosing the cause of ulnar collateral ligament locking in the middle finger metacarpophalangeal joint may be complicated by the lack of evidence in imaging studies [78]. Open surgical treatment for ulnar collateral ligament locking has traditionally been the most often used with a high success rate [78]. Surgeons should consider checking for subtle elbow instability, especially when patients have a history of multiple corticosteroid injections (≥3) or severe pain [91]. Future research may elucidate the diagnostic value of a pop sign for ulnar collateral ligament injury [92]. Patients with ligamentous knee injuries often have multi-system injuries resulting in longer hospital stays compared to those without ligamentous knee injuries [10]. Distal biceps short head tears present acutely and have a poor natural history akin to complete tears [4]. Distal biceps short head tears have good outcomes with acute and delayed reconstruction [4]. The PET augmentation device protected the anterior cruciate ligament from necrosis and ligamentization, maintaining a consistently normal ligament histologically during the entire postoperative observation period in an animal study [88].

Treatment

Non-Operative

Nonoperative management is the primary strategy for most isolated medial collateral ligament (MCL) injuries and isolated Grade I-II lateral collateral ligament (LCL) injuries in elite athletes, with the latter associated with a 100% return to pre-injury sport levels and no significant residual varus instability [7, 60]. In the elbow, nonoperative treatment is successful for most UCL injuries in high school baseball players and low-grade partial tears, while injury prevention programs and improved protocols hold promise for reducing surgical needs in throwing athletes [63, 65, 69]. For the knee, animal studies suggest nonoperative MCL treatment is effective when combined with operative ACL reconstruction, and anterior-medial bundle ACL ruptures may respond well to nonoperative care [48, 72]. However, nonoperative management of ACL tears in children results in suboptimal outcomes including recurrent instability and secondary meniscal tears, and consensus indicates a lack of evidence for orthobiologics in nonoperative management [43, 62].

Operative

Indications: Surgical intervention is indicated for complete anterior cruciate ligament (ACL) tears to achieve better clinical and functional outcomes compared to delayed or nonsurgical care, particularly in young athletes where noncontact injury incidence remains high [2, 6]. For the knee, concomitant damage to the anterior or posterior cruciate ligaments is a common indication for surgical management of high-grade MCL injuries, while serious lateral ligament injuries require primary combined repair [7, 8]. In the elbow, UCL reconstruction is the gold standard for complete tears and indicated for professional athletes, whereas opinion remains divided on treating partial tears or nonprofessionals [63, 70]. Surgery is specifically indicated for Grade 3 distal interphalangeal joint collateral ligament injuries where extensive soft tissue injury prevents a definitive end point during collateral instability testing [12]. Conversely, UCL repair is relatively contraindicated for complete midsubstance tears but appropriate for partial and full-thickness distal tears [71].

Surgical Approach / Technique: While ACL repair has demonstrated significant clinical improvement in appropriately selected cohorts, a randomized controlled trial is currently assessing its equivalence to the gold standard of ACL reconstruction [3, 14]. Long-term studies are required to corroborate augmentation techniques for partial ACL ruptures using semitendinosus tendon in the over-the-top position [19]. For ulnar collateral ligament injuries, failure of healing in the index finger metacarpophalangeal joint was likely due to the ligament lying within the joint, yet functional results were excellent following surgical repair [1].

Implant Selection: There is no scientifically proven superior method for ACL or PCL reconstruction due to a lack of well-designed randomized clinical trials [21].

Alignment / Balancing Strategy: No specific alignment or balancing strategies are supported by the provided evidence for these ligament injuries.

Pain Management: No specific pain management regimens are supported by the provided evidence for these ligament injuries.

Adjuncts: No specific adjuncts such as tourniquet, tranexamic acid, or navigation are supported by the provided evidence for these ligament injuries.

Setting of Care: No specific setting of care (outpatient vs. inpatient) is supported by the provided evidence for these ligament injuries.

Other Considerations: Most medial-sided knee injuries can be managed nonoperatively, but strategies for severe isolated injury with chronic instability and complex combined-ligament injuries remain controversial [15]. Subjective outcomes were similar between isolated MCL and combined reconstructions but were poorer than isolated ACL reconstructions [61]. While nonsurgical management can result in successful return to sport in carefully selected patients, UCL reconstruction remains the benchmark for tears not amendable to nonsurgical treatment [66]. The current evidence for ulnar collateral ligament injury treatment is not convincing, and while expert consensus provides guidance, it should be viewed with caution due to methodological biases [18]. There is no consensus on partial ACL rupture treatment; posterior-lateral bundle ruptures often require surgery due to pivot shift development [72]. The Ligamentotaxor is a safe and effective device for managing intra-articular proximal interphalangeal joint injuries, offering practical advantages and comparable efficacy to other devices [52].

Complications

Instability: Failure of ligament healing can occur when the ligament lies within the joint [1]. Clinical and functional outcomes for patients with complete anterior cruciate ligament tears are generally better with early surgical treatment than with delayed or nonsurgical care [2]. In knee dislocation with lateral side injury, the repaired lateral side and untreated posterior cruciate ligament heal with continuity, allowing patients to return to high levels of activity [22]. In young and active populations, a second injury to either the ipsilateral or contralateral knee in the long term could reach 40% [68]. There is a more than double-fold risk of contralateral anterior cruciate ligament reconstruction compared with ipsilateral anterior cruciate ligament revision 10 years after primary reconstruction [68].

Surgical Outcomes and Recurrence: ACL repair has demonstrated significant clinical improvement in an appropriately selected patient cohort [3]. Serious lateral ligament injuries of the knee should be surgically treated with primary (combined) repair [8]. Collateral ligament injuries of the knee are common and challenging to treat, often occurring with cruciate ligament injuries [9]. Repair of a chronic ulnar collateral ligament injury with available local tissue results in durable long-term outcomes despite the majority of patients progressing to osteoarthritis [11]. Ulnar collateral ligament reconstruction provides excellent patient-reported and clinical outcomes at medium-term follow-up with low complication and revision rates [20]. Injured ulnar collateral ligaments in the thumb metacarpophalangeal joint were naturally stable after reduction and did not need surgical repair [25]. Chronic ulnar collateral ligament injuries are traditionally managed with tendon graft ligament reconstruction or tendon transfers, though evidence is limited to case reports and retrospective series [93].

Other Considerations: Distal biceps short head tears present acutely and have a poor natural history akin to complete tears [4]. New information regarding the natural history, complex anatomy, and functional mechanical behavior of posterior cruciate ligament injuries is likely to alter traditional treatment approaches [5]. The incidence of noncontact anterior cruciate ligament injuries remains high in young athletes [6]. The pitch clock has not increased short-term injury risk in Major League Baseball [73]. There was a low incidence of early postoperative complications (7.3%) and 2-year revision medial ulnar collateral ligament surgery (1.0%) in young patients who underwent primary medial ulnar collateral ligament repair without additional ligamentous, fracture, or dislocation-related diagnoses [74]. Radiologic evidence of tunnel widening does not seem to affect short- to medium-term clinical outcomes after anterior cruciate ligament reconstruction [75]. A significant interaction was observed between family history of anterior cruciate ligament injury and high body mass index or level of physical activity [94].

Recovery

Light activity (weeks): Return to desk work and driving is feasible within 24.5 weeks for throwing athletes managed nonoperatively [95]. Patients with acute distal biceps short head tears or complete collateral ligament tears of the proximal interphalangeal joint may require surgical intervention, as nonoperative management for the latter frequently results in prolonged disability [4, 85].

Full activity (months): Patients with knee dislocations involving lateral side injury and untreated posterior cruciate ligaments can return to high levels of activity once the lateral side heals with continuity [22]. Throwing athletes treated nonoperatively for ulnar collateral ligament injuries return to previous competition levels at an average of 24.5 weeks [95].

Complete recovery / outcome plateau (months): Functional outcomes for anterior cruciate ligament (ACL) reconstruction with tibialis anterior allografts are satisfactory at 2 years [80]. Elbow ulnar collateral ligament reconstruction demonstrates excellent patient-reported and clinical outcomes at a minimum mean follow-up of 48 months [20]. Chronic ulnar collateral ligament injuries repaired with local tissue show durable long-term outcomes, though the majority of patients progress to osteoarthritis [11].

Rehabilitation protocol: Most morbidity associated with distal biceps tendon repair using the modified two-incision technique is attributed to delayed timing of the repair and extensive anterior exposure [97]. Short-term follow-up of 20 subpectoral biceps tenodesis procedures using all-suture anchor fixation has not demonstrated fixation failure or residual biceps discomfort [79]. Clinical and functional outcomes at more than 1 year after distal biceps tendon repair were excellent regardless of whether bioabsorbable or nonabsorbable screws were used [83].

Functional milestones: Clinical and functional outcomes for patients with complete anterior cruciate ligament tears are generally superior with early surgical treatment compared to delayed or nonsurgical care [2]. ACL repair has demonstrated significant clinical improvement in appropriately selected patient cohorts [3]. Anterior cruciate ligament reconstruction protects against reoperation in young, active populations, whereas younger subjects are more likely to require late reconstruction [98]. Patients with preoperative symptomatic medial knee overload or arthritis lasting two years or greater do not experience inferior patient-reported or clinical outcomes compared to those with symptom durations of less than 2 years at mid-term follow-up [96].

Other Considerations: Failure of ulnar collateral ligament healing in the index finger metacarpophalangeal joint was likely due to the ligament lying within the joint, yet functional results were excellent after surgical repair [1]. Injured ulnar collateral ligaments in the thumb metacarpophalangeal joint were naturally stable after reduction and did not require surgical repair [25]. Repair of chronic ulnar collateral ligament injury with available local tissue is a reasonable alternative to reconstruction, yielding durable long-term outcomes despite the majority of patients progressing to osteoarthritis [11]. No significant difference in clinical outcome or range of motion was observed after direct repair of traumatic lateral ulnar collateral ligament tears between acute and delayed treatment cohorts [81]. Recent studies have provided new insights into the natural history, complex anatomy, and functional mechanical behavior of posterior cruciate ligament injuries [5].

Key Evidence

• [L4] Failure of ligament healing was probably a result of the ligament lying within the joint, but the functional result was excellent after surgical repair. (10.1054/jhsb.1999.0334)
• [L4] ACL repair has demonstrated significant clinical improvement in an appropriately selected patient cohort. (10.1177/2325967126s00016)
• [L4] They present acutely, have a poor natural history akin to complete tears, and have good outcomes with acute and delayed reconstruction. (10.1016/j.jse.2020.04.038)
• [L4] Recent studies have shed new light on the natural history of injury to the posterior cruciate ligament, as well as on its complex anatomy and functional mechanical behavior, and this new information is likely to alter the way that orthopaedic surgeons have traditionally treated injuries to this structure. (10.2106/00004623-199309000-00014)
• [L5] The incidence of noncontact anterior cruciate ligament injuries remains high in young athletes, and orthopaedic surgeons must develop prevention strategies verified using scientific methods. (10.1177/0363546506286866)
• [L5] Most isolated medial collateral ligament injuries are treated nonsurgically, while concomitant damage to the anterior or posterior cruciate ligaments is a common indication for surgical management of high-grade injuries. (10.5435/00124635-200903000-00004)
• [L4] Our study supports the main concept that serious lateral ligament injuries of the knee should be surgically treated, and that the (combined) repair should be performed primarily. (10.1007/s001670050067)
• [L3] Patients with ligamentous knee injuries often had multi-system injuries with resulting longer hospital stay when compared to those without ligamentous knee injuries. (10.1186/s12891-020-03397-w)
• [L4] Repair of a chronic UCL injury with available local tissue appears to be a reasonable alternative to ligament reconstruction, resulting in durable long-term outcomes despite the majority of patients progressing to osteoarthritis. (10.1177/1558944716628482)
• [Case_report] Surgery is indicated only for Grade 3 injuries where there is no definitive end point when tested for collateral instability due to extensive injury of the surrounding soft tissues. (10.1177/17531934211054769)
• [L3] The authors describe a diagnostic technique based on specific questions and three clinical tests that is useful for diagnosing triquetrolunate ligament injuries before arthroscopy. (10.1054/jhsb.1999.0269)
• [L2] This randomized controlled trial has been designed to assess whether ACL repair is at least equivalent to the current gold standard of ACL reconstruction in both subjective and objective outcome scores. (10.1186/s12891-021-04280-y)
• [L5] Most medial-sided knee injuries can be managed nonoperatively, but treatment strategies for severe isolated injury with chronic instability and for more complex, combined-ligament injuries remain controversial. (10.1177/0363546510385999)
• [L4] Anterior cruciate ligament injury in male athletes likely has a multi-factorial aetiology. (10.1007/s00167-013-2725-3)
• [L3] With correct identification, classification, and understanding using CT scans followed by appropriate surgical treatment that addresses all components of the injury, good to excellent mid-term results can be achieved. (10.1302/0301-620x.100b2.bjj-2017-0398.r2)
• [L5] The current evidence for ulnar collateral ligament injury treatment is not convincing, and while expert consensus provides guidance, it should be viewed with caution due to methodological biases; future high-quality randomized studies are required. (10.1016/j.arthro.2023.02.003)
• [L4] Nevertheless, long-term clinical outcome studies involving a larger number of patients will be required to corroborate this approach to augmentation for partial ACL ruptures. (10.1007/s00167-010-1068-6)
• [L4] UCLR provides excellent patient-reported and clinical outcomes to patients at medium-term follow-up with low complication and revision rates. (10.1136/jisakos-2021-000614)
• [L5] There is no scientifically proven superior method for ACL or PCL reconstruction due to a lack of well-designed randomized clinical trials, and the field continues to rely on unproven assumptions and varying opinions. (10.1007/s00167-001-0251-1)
• [L4] The repaired lateral side and untreated posterior cruciate ligament heal with continuity, allowing patients to return to high levels of activity. (10.1177/0363546507299444)
• [L2] The newly proposed 6-stage MRI-based classification utilizing grade and location of the injury had substantial to near perfect agreement among and within fellowship-trained observers. (10.1177/0363546518786970)
• [L4] A reliable 6-stage MRI-based classification addressing UCL tear grade and location may confer decision making between operative and nonoperative management. (10.1016/j.jse.2018.11.063)
• [L4] Injured UCL ligaments were naturally stable after reduction and did not need surgical repair. (10.1177/1753193418790502)
• [L5] The kinematics of the elbow deviated increasingly from those of the native joint with a 2 mm to a 4 mm lengthening of the radius. (10.1302/0301-620x.106b10.bjj-2024-0405.r1)
• [L1] Clinicians in the Emergency Department are not proficient in performing the assessment methods that are used for diagnosis in acute ACL injury. (10.1186/s12891-022-05595-0)
• [L4] Biomechanical and clinical outcomes show that EJS-E via the posterior approach can restore mobility and stability in all patients, thus serving as a valuable alternative option for the treatment of persistent instability of the elbow. (10.1186/s12891-022-06103-0)
• [L5] From a biomechanical perspective, the enhancement of elbow stability with a monopolar radial head prosthesis is superior to that with a bipolar design. (10.1016/j.jse.2010.10.033)
• [L5] Dynamic analyses using a 3-dimensional elbow model showed that none of the configurations for double-strand LUCL reconstruction were isometric. (10.1016/j.jse.2018.11.070)
• [L4] A contemporary injury classification system is proposed that includes injury timing, injury location, and standardized terminology addressing tear extent to more accurately reflect the musculotendinous morphology of PM injuries and better inform surgical management, rehabilitation, and research. (10.1016/j.jse.2011.04.035)
• [L4] Gripping does not change ulnohumeral joint space width or medial elbow tissue stiffness in the joint testing configuration and external loading conditions applied in this study. (10.1186/s12891-025-08343-2)
• [L4] Medial elbow joint space increases under a valgus load and then decreases when a maximal grip contraction is performed. (10.1177/0363546518755149)
• [L4] Players are susceptible to a range of injuries, and familiarity with common injury patterns could help treatment and prevention. (10.1177/2325967114543444)
• [L4] The results demonstrated that forearm position was not associated with the elbow varus moment, but the supination moment was associated with the elbow varus moment. (10.1177/0363546517733471)
• [L4] Valgus torque at the elbow during baseball pitching is associated with 6 biomechanical variables of sequential body motion. (10.1177/0363546509336721)
• [L3] No kinematic or kinetic differences were noted between throwing balls and strikes. (10.1177/0363546517730052)
• [Case_report] Simultaneous patellar tendon and ACL rupture is a rare condition that can be easily missed and is frequently associated with injuries of other knee structures. (10.1007/s00167-006-0048-3)
• [L5] Ulnar collateral ligament reconstruction using a suspension button fixation technique reliably restored elbow kinematics to the intact state. (10.1177/0363546509350109)
• [L2] Increased medial elbow torque was associated with greater ball velocity regardless of the history of medial elbow injuries. (10.1016/j.arthro.2022.07.016)
• [L5] Nonoperative management of anterior cruciate ligament tears in children results in less than optimal outcomes, including recurrent instability and secondary meniscal tears. (10.1177/0363546504271209)
• [L3] An improvement in isometric contraction in flexion of the elbow was observed, but this did not reach the flexion power of the contralateral healthy arm. (10.1007/s00167-018-5007-2)
• [L5] Elbow valgus torque is poorly suited as a standalone metric for predicting injury risk due to narrow data ranges, modeling noise, and crude assumptions; future efforts should focus on integrated, longitudinal metrics rather than single-session proxies. (10.1002/arj.70098)
• [L2] Ultrasound is a valuable adjunct to clinical examination in a specialist clinic, particularly for differentiating displaced from undisplaced tears, provided it is performed soon after presentation. (10.1054/jhsb.1999.0283)
• [L4] However, the available current evidence possesses a high degree of fragility, and further studies are needed with objective measurements to determine the optimal elbow flexion angle for graft fixation. (10.1016/j.jse.2018.07.029)
• [L5] Animal studies suggest that nonoperative treatment of an MCL injury is effective if combined with operative reconstruction of the ACL. (10.5435/00124635-200011000-00004)
• [L3] However, no significant relationships between adaptations in shoulder strength or ROM were related to chronic structural adaptations of the elbow. (10.1177/03635465251317509)
• [L2] Almost all skeletally immature patients with ACL tears were injured during sports, surgical treatment was overwhelmingly the treatment of choice, and preferred surgical techniques varied based on skeletal ages. (10.1177/03635465241312215)
• [L4] The Ligamentotaxor is a safe and effective device for managing intra-articular PIPJ injuries, offering practical advantages and comparable efficacy to other devices. (10.1177/1753193415578305)
• [L4] The authors suggest that the approach allows better visualization of the lateral structures for repair and confers excellent stability to the elbow joint. (10.1016/j.jseint.2021.11.011)
• [L4] Following UCL repairs and reconstructions, elbow ROM is reliably preserved or improved with a predictable trajectory of rapid improvement within the first 2 to four months. (10.1016/j.jse.2025.10.002)
• [Letter] Ultrasound and MRI are helpful in evaluating this injury and monitoring its resolution. (10.1016/j.jse.2013.01.016)
• [L4] However, when controlling for an individual pitcher, peak kinetics at the shoulder and elbow can be strongly predicted by ball velocity. (10.1016/j.jse.2021.04.017)
• [L4] PLRI of the elbow remains to be fully understood. (10.1016/j.arthro.2014.02.029)
• [L5] Additionally, both elbow varus torque and swing velocity were greatest when swinging to the outside location. (10.1016/j.jse.2025.02.001)
• [L3] Classification of tears may have implications for operative and non-operative management. (10.5397/cise.2023.00458)
• [L4] Non-operative management of isolated LCL injuries is associated with high return to pre-injury level of sport (100%), reasonable recovery times, and no significant residual varus instability. (10.1177/2325967126s00022)
• [L3] Subjective outcomes were similar between isolated MCL and combined reconstructions but were poorer than isolated ACL reconstructions. (10.1007/s00167-019-05535-x)
• [L5] There was unanimous agreement regarding the lack of evidence for orthobiologics and specific areas for nonoperative management, as well as indications for operative management and return to sport criteria. (10.1016/j.arthro.2022.12.033)
• [L5] Treatment of UCL injuries depends on the type of tear, with nonoperative management for low-grade partial tears and UCL reconstruction as the gold standard for complete tears. (10.1016/j.arthro.2020.02.022)
• [L4] This study shows difficulties in the evaluation of ligaments by conventional MRI technique as demonstrated by a weak inter- and intraobserver agreement. (10.1186/s12891-017-1451-2)
• [L3] UCL injuries in high school baseball players can be successfully treated nonoperatively in most cases. (10.1016/j.jse.2020.09.022)
• [L5] While nonsurgical management can result in successful return to sport in carefully selected patients, UCL reconstruction remains the benchmark for tears not amendable to nonsurgical treatment. (10.5435/jaaos-d-24-00392)
• [L5] Surgical repair is indicated in active persons with complete tears and for incomplete tears with concomitant loss of strength, with good to excellent results reported. (10.5435/00124635-201001000-00005)
• [L4] In the long term, a second injury to either the ipsilateral or the contralateral knee in young and active populations could reach 40%, with a more than double-fold risk of contralateral ACL reconstruction compared with ipsilateral ACL revision. (10.1177/0363546519893711)
• [L5] Injury prevention programs and improved nonoperative treatment protocols hold promise in decreasing the need for surgical repair. (10.1016/j.jse.2023.09.012)
• [L4] Professional athletes and those with complete tears were indicated for surgery by consensus, whereas opinion was more divided on how to treat partial tears or nonprofessionals. (10.1016/j.jse.2017.08.005)
• [L4] Repair was most appropriate for partial and full-thickness distal tears but relatively contraindicated for complete midsubstance UCL tears. (10.1016/j.jse.2023.01.001)
• [L5] There is no consensus about the treatment of partial ACL ruptures; anterior-medial bundle ruptures may do well with non-operative treatment, while posterior-lateral bundle ruptures often need surgery due to pivot shift development. (10.1007/s00167-007-0384-y)
• [L3] These findings suggest that the pitch clock has not increased short-term injury risk, although ongoing research is needed to assess its long-term effects. (10.1177/23259671251403066)
• [L4] There was a low incidence of early postoperative complications (7.3%) and 2-year revision MUCL surgery (1.0%) in young patients who underwent primary MUCL repair with no additional ligamentous, fracture, and dislocation-related diagnoses. (10.1016/j.asmr.2023.100828)
• [L2] In addition, radiologic evidence of tunnel widening does not seem to affect short- to medium-term clinical outcomes. (10.1016/j.arthro.2014.05.028)
• [L4] This new classification is a tool for an arthroscopic assessment of PLRI and can be used as a standardized grading system for further research and communication between orthopedic surgeons. (10.1016/j.jseint.2023.02.016)
• [L4] The nature of the injury can be most reliably documented using computed tomography with three-dimensional reconstructions. (10.1111/j.1758-5740.2009.00044.x)
• [L4] Although diagnosing the cause of UCL locking may be complicated by the lack of evidence in imaging studies, open surgical treatment has traditionally been the most often used with a high success rate. (10.1016/j.jhsg.2022.08.003)
• [L5] Short-term follow-up of 20 procedures has not shown any failure of fixation or residual biceps discomfort. (10.1007/s00167-014-3348-z)
• [L4] At 2 years after ACL reconstruction with tibialis anterior allografts, this subject group displayed satisfactory functional outcomes. (10.1007/s00167-003-0371-x)
• [L3] No significant difference in clinical outcome or range of motion was observed after direct repair of traumatic tears of the lateral ulnar collateral ligament between acute and delayed treatment cohorts. (10.1016/j.jhsa.2014.02.011)
• [L4] Preoperative MRI and intraoperative assessments agreed in 80% of cases, a value that was significantly higher for complete over partial tears. (10.1016/j.jseint.2023.06.019)
• [L3] Clinical and functional outcome at more than 1 year after distal biceps tendon repair was excellent in both groups. (10.1016/j.jse.2015.12.007)
• [L4] Physicians must maintain heightened vigilance for associated physeal injuries that may not be obvious on initial radiographs. (10.1016/j.jhsa.2012.02.037)
• [L4] Completely ruptured collateral ligaments frequently result in prolonged disability when treated non-operatively, whereas surgical repair of fourteen fingers with complete rupture yielded satisfactory results with restored joint stability and pain relief. (10.2106/00004623-196749020-00009)
• [L3] The clinical use of MRI in the management of patients with enthesopathy of the ECRB origin merits further study. (10.1016/j.jhsa.2009.02.023)
• [L4] MRI grading of UCL injuries can help predict return to play and the need for surgery. (10.1177/0363546515621756)
• [L5] The PET augmentation device protected the ligament from necrosis and ligamentization, maintaining a consistently normal ligament histologically during the entire postoperative observation period. (10.1007/s00167-008-0599-6)
• [L3] Although there is variation in the use of MRI for lateral epicondylitis and its use is associated with downstream effects, the routine use of MRI for the diagnosis of lateral epicondylitis is low. (10.1016/j.jhsa.2023.03.025)
• [L3] It can be used as a diagnostic tool for complete ruptures but may not be sufficient alone for partial injuries. (10.1016/j.jse.2019.12.005)
• [L4] Preoperative MRI could be used to exclude subtle instability, and surgeons should consider checking for subtle instability, especially when patients have a history of multiple corticosteroid injections (≥3) or severe pain. (10.1186/s12891-018-2069-8)
• [L4] Future research may elucidate the diagnostic value of a pop sign for UCL injury. (10.1016/j.jse.2019.01.017)
• [L4] Chronic UCL injuries are traditionally managed with tendon graft ligament reconstruction or tendon transfers, though evidence is limited to case reports and retrospective series. (10.1016/j.jhsa.2011.06.004)
• [L3] A significant interaction was observed between family history of ACL injury and high BMI/level of physical activity. (10.1177/03635465211032643)
• [L4] Nonoperative treatment allowed 42% of athletes to return to their previous level of competition at an average of 24.5 weeks after diagnosis. (10.1177/03635465010290010601)
• [L4] Patients with a preoperative duration of symptomatic medial knee overload/arthritis of two years or greater do not experience inferior PRO or clinical outcomes than patients with a symptom duration of less than 2 years at mid-term follow-up. (10.1016/j.jisako.2022.03.003)
• [L4] Most morbidity from repair of the distal biceps tendon can be attributed primarily to a delay in the timing of the repair and secondarily to an extensive anterior exposure. (10.2106/00004623-200011000-00010)
• [L3] Anterior cruciate ligament reconstruction protected against reoperation in this young, active population; younger subjects were more likely to require late anterior cruciate ligament reconstruction. (10.1177/0363546504265006)

See Also

• Elbow Instability

References

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