Youth Pitcher Fatigue: Medial Elbow Laxity, Ultrasonographic Assessment of Flexor-Pronator Mass Energy Depletion, and Association With Pitch Count.

Background: Ulnar collateral ligament (UCL) injuries in youth pitchers continue to be concerning despite the institution of pitch count limits. Flexor-pronator mass fatigue can lead to diminished dynamic stability, resulting in greater stress on the UCL. Purpose/Hypothesis: To evaluate fatigue of the flexor-pronator mass by assessing changes in medial elbow laxity; noninvasively characterizing alterations in muscle glycogen; and identifying changes in subjective fatigue, strength, range of motion (ROM), pitching velocity, and accuracy with increasing pitches thrown by youth pitchers to their recommended 75-pitch count limit. It was hypothesized that, with increased pitches, medial elbow laxity would increase and that the glycogen content of the flexor-pronator mass would decrease. Study Design: Descriptive laboratory study. Methods: Healthy male pitchers aged 10 years (n = 22) threw 3 sets of 25 pitches with 12 minutes between sets (3 timepoints). Bilateral ulnohumeral joint gapping was measured by applying a standardized valgus force and utilizing ultrasound imaging. Relative changes in muscle glycogen in the bilateral flexor carpi radialis (FCR), and the flexor digitorum superficialis/flexor carpi ulnaris (FDS/FCU) muscles were measured with ultrasound software and recorded as fuel percentiles. Additional measures obtained included subjective fatigue, strength, ROM, velocity, and accuracy. Results: There were no differences in medial elbow joint-line gapping between the throwing and nonthrowing arms or between timepoints. The throwing arm demonstrated a significant decline in fuel percentile of the FCR from baseline to after 75 pitches (P = .05). There were no differences across timepoints for FDS/FCU fuel percentile values. Fatigue measurements for both arms were significantly higher at all timepoints compared with baseline (P≤ .03). Grip strength of the dominant arm after 75 pitches was decreased significantly compared with after 25 pitches (P = .02). Conclusion: Although an increase in medial elbow joint gapping was not demonstrated within the recommended 75 pitch count limit in 10-year-olds, a relative decrease in glycogen stores of the flexor-pronator mass did occur, as well as a decrease in grip strength, with increasing subjective fatigue. Clinical Relevance: This study provides a foundation for further objective testing of physiologic changes that occur with pitching to better guide pitch count limits and improve the safety of young athletes.

Evaluating the Reliability and Quality of YouTube Videos Regarding Medial Collateral Ligament Knee Injury as a Patient Education Resource.

OBJECTIVES: The purpose of this study was to assess the educational reliability and quality of videos shared on YouTube regarding medial collateral ligament (MCL) injuries of the knee. METHODS: Using the search keywords "medial collateral ligament" on YouTube, the first 50 videos were evaluated by two independent reviewers. Video characteristics were extracted, and each video was categorized by upload source and content type. Three scoring systems were used to evaluate the videos: the Journal of the American Medical Association (JAMA) Benchmark Score to assess a video's reliability; the Global Quality Score (GQS) to assess educational quality; the novel MCL Specific Score (MCL-SS) to assess MCL-specific content quality. Linear regression analyses were conducted to explore relationships between video characteristics and scores. RESULTS: Collectively, the videos were viewed 5,759,427 times with a mean number of views per video of 115,189 ± 177,861. The mean JAMA score was 1.8, GQS was 2.1, and MCL-SS was 5.6, indicating both poor reliability and quality. Only videos uploaded by physicians showed a statistically significantly higher mean MCL-SS (P = .032) but were still of low quality with a mean MCL-SS of 9.2 ± 5.9. Multivariate linear regression revealed that videos uploaded by physicians were statistically significant predictors of greater MCL-SS (ß = 4.108; P = .029). Longer video durations were statistically significant predictors of greater GQS (ß = .001; P = .002) and MCL-SS (ß = .007; P < .001). CONCLUSIONS: YouTube videos regarding MCL injuries, despite their popularity, were found to be on average of poor overall reliability and quality as measured by JAMA, GQS, and MCL-SS. LEVEL OF EVIDENCE: III - Cross-sectional Study.

Anatomical evaluation of the superficial medial collateral ligament distal tibial attachment of the knee.

This study aimed to evaluate the superficial medial collateral ligament distal tibial attachment (sMCL-dTA) morphologically and morphometrically. Seventeen unpaired formalin-fixed cadaveric knees were used. The sMCL was divided into anterior and posterior sections in the paracoronal plane along the midline of the sMCL. The distance from the medial edge of the tibial plateau and the joint line to the proximal margin, center, and distal margin of the sMCL-dTA and the length of the sMCL-dTA were measured in the anterior section, respectively. The sMCL-dTA was histologically observed in the posterior section with hematoxylin and eosin and Masson's trichrome staining. The distance from the medial edge of the tibial plateauto the proximal margin, center, and distal margin of the sMCL-dTA were 38.1 ± 4.2, 49.7 ± 4.4, and 61.5 ± 5.1 mm, respectively. The perpendicular distance from the joint line to the proximal margin, center, and distal margin of the sMCL-dTA were 36.1 ± 4.0, 47.4 ± 4.2, and 59.1 ± 4.8 mm, respectively. The length of the sMCL-dTA was 23.6 ± 3.2 mm. Histologically, the sMCL-dTA was formed by two layers of collagen fibers: the unidirectional fibrous layer and the multidirectional fibrous layer. The respective thicknesses of the two layers both decreased distally. The anatomical location, the length, and the attachment morphology of sMCL-dTA have been clarified using human cadaveric knees. Anatomical data in the present study contribute to the quality of surgery associated with sMCL-dTA.

Collateral ligament strain is linearly related to coronal lower limb alignment: A biomechanical study.

PURPOSE: The purpose of this study was to analyse the influence of coronal lower limb alignment on collateral ligament strain. METHODS: Twelve fresh-frozen human cadaveric knees were used. Long-leg standing radiographs were obtained to assess lower limb alignment. Specimens were axially loaded in a custom-made kinematics rig with 200 and 400 N, and dynamic varus/valgus angulation was simulated in 0°, 30°, and 60° of knee flexion. The changes in varus/valgus angulation and strain within different fibre regions of the collateral ligaments were captured using a three-dimensional optical measuring system to examine the axis-dependent strain behaviour of the superficial medial collateral ligament (sMCL) and lateral collateral ligament (LCL) at intervals of 2°. RESULTS: The LCL and sMCL were exposed to the highest strain values at full extension (p < 0.001). Regardless of flexion angle and extent of axial loading, the ligament strain showed a strong and linear association with varus (all Pearson's r ≥ 0.98; p < 0.001) and valgus angulation (all Pearson's r ≥ -0.97; p < 0.01). At full extension and 400 N of axial loading, the anterior and posterior LCL fibres exceeded 4% ligament strain at 3.9° and 4.0° of varus, while the sMCL showed corresponding strain values of more than 4% at a valgus angle of 6.8°, 5.4° and 4.9° for its anterior, middle and posterior fibres, respectively. CONCLUSION: The strain within the native LCL and sMCL was linearly related to coronal lower limb alignment. Strain levels associated with potential ultrastructural damages to the ligaments of more than 4% were observed at 4° of varus and about 5° of valgus malalignment, respectively. When reconstructing the collateral ligaments, an additional realigning osteotomy should be considered in cases of chronic instability with a coronal malalignment exceeding 4°-5° to protect the graft and potentially reduce failures. LEVEL OF EVIDENCE: There is no level of evidence as this study was an experimental laboratory study.

Traumatic Triceps and Medial Ulnar Collateral Ligament Rupture in an Adolescent Mogul Skier: A Case Report.

Triceps tendon ruptures are uncommon injuries that account for less than 1% of all upper extremity tendon injuries. Medial ulnar collateral ligament injury (mUCL), while common in overhead athletes as a result of valgus forces during the throwing mechanics, has scarcely been reported in non-overhead, throwing individuals. Traumatic assault to the elbow may result in the rupture of the triceps tendon with concomitant mUCL injury. As such an injury pattern typically presents in middle-aged males, weightlifters, or American football players from eccentric overloading of the elbow. We present an adolescent, elite-level, competitive skier with traumatic onset distal triceps rupture with concomitant medial ulnar collateral ligament rupture suffered via a fall on an outstretched hand (FOOSH) mechanism. Magnetic resonance imaging (MRI) showed acute full-thickness avulsion of the distal triceps tendon occurring at the olecranon enthesis. An open tendon repair was performed, and the patient was able to report significant symptom resolution over the course of six months postoperatively and successfully return to elite-level competition. This was a unique and rare case of triceps tendon rupture with concomitant mUCL injury in an adolescent via a non-contact, high-velocity injury mechanism. While a rare injury combination, this case nevertheless identifies an area of research not currently extensively covered-trampoline training and associated injuries in adolescents. This case, therefore, not only adds a novel dimension to the understanding of triceps and mUCL injuries in young athletes but also underscores the need for heightened awareness and specific safety protocols in sports training involving equipment like trampolines.

Double-Bundle Medial Collateral Ligament Reconstruction Improves Anteromedial Rotatory Instability.

BACKGROUND: New techniques have been proposed to better address anteromedial rotatory instability in a medial collateral ligament (MCL)-injured knee that require an extra graft and more surgical implants, which might not be feasible in every clinical setting. PURPOSE: To investigate if improved resistance to anteromedial rotatory instability can be achieved by using a single-graft, double-bundle (DB) MCL reconstruction with a proximal fixation more anteriorly on the tibia, in comparison with the gold standard single-bundle (SB) MCL reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator in intact knee, superficial MCL/deep MCL-deficient, and reconstruction states. Three different reconstructions were tested: DB MCL no proximal tibial fixation and DB and SB MCL reconstruction with proximal tibial fixation. Knee kinematics were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8 N·m of valgus rotation (VR), 5 N·m of external tibial rotation, 5 N·m of internal tibial rotation, combined 89 N of anterior tibial translation and 5 N·m of external rotation for anteromedial rotation (AMR) and anteromedial translation (AMT). The differences between each state for every measurement were analyzed with VR and AMR/AMT as primary outcomes. RESULTS: Cutting the superficial MCL/deep MCL increased VR and AMR/AMT in all knee positions except at 90° for VR (P < .05). All reconstructions restored VR to the intact state except at 90° of knee flexion (P < .05). The DB MCL no proximal tibial fixation reconstruction could not restore intact AMR/AMT kinematics in any knee position (P < .05). Adding an anterior-based proximal tibial fixation restored intact AMR/AMT kinematics at ≥30° of knee flexion except at 90° for AMT (P < .05). The SB MCL reconstruction could not restore intact AMR/AMT kinematics at 0° and 90° of knee flexion (P < .05). CONCLUSION: In this in vitro cadaveric study, a DB MCL reconstruction with anteriorly placed proximal tibial fixation was able to control AMR and AMT better than the gold standard SB MCL reconstruction. CLINICAL RELEVANCE: In patients with anteromedial rotatory instability and valgus instability, a DB MCL reconstruction may be superior to the SB MCL reconstruction, without causing extra surgical morbidity or additional costs.

Outcomes After Single-Stage Anatomic Multiligament Knee Reconstruction With Early Range of Motion in Adolescents.

Background: Multiligament knee injuries (MLKI), rare in adolescents, are challenging injuries that require complex surgical reconstruction. Historically, nonanatomic reconstructions have been associated with prolonged immobilization and failure to restore normal knee biomechanics, resulting in arthrofibrosis and high rates of graft failure. Purpose: To describe the clinical and patient-reported outcomes (PROs) for adolescent patients treated with single-stage anatomic multiligament knee reconstruction. Study Design: Case series; Level of evidence, 4. Methods: A single-center retrospective study was performed of patients ≤18 years old who underwent reconstruction of MLKIs by a single surgeon between 2014 and 2019 using a single-stage anatomic technique, with protected weightbearing and early range of motion. Complications were defined as infection, arthrofibrosis, deep vein thrombosis (DVT) or pulmonary embolus, and secondary surgery. PROs, including the pediatric version of the International Knee Documentation Committee (Pedi-IKDC) and the Tegner activity score, were obtained at a minimum of 2 years postoperatively. Results: Included were 30 patients (21 male, 9 female; mean age, 15.4 years). The most common ligamentous reconstruction types were anterior cruciate ligament (ACL) + fibular collateral ligament (12 patients; 40%) and ACL + medial collateral ligament (9 patients; 30%). Three patients (10%) had secondary surgeries, including irrigation and debridement of a granuloma, a staged osteochondral allograft transplantation to a lateral femoral condyle impaction fracture, and repair of a medial meniscal tear and lateral femoral condyle fracture associated with new injuries 2 years after ACL + fibular collateral ligament reconstruction. Two patients (7%) developed arthrofibrosis and 1 patient (3%) developed DVT. PRO scores obtained at a mean of 37 months postoperatively included a mean Pedi-IKDC of 87 (range, 52-92) and a median highest Tegner score at any point postoperatively of 9 (range, 5-10). Of the patients who were athletes before their injury, 70% returned to the same or higher level of sport postoperatively. Conclusion: Reconstruction of MLKI in this series of adolescents with single-stage anatomic techniques and early range of motion resulted in low rates of secondary surgery, few complications, and good knee function as well as PRO scores at mean 3-year follow-up.

Early Surgery for Partial Tears of the Ulnar Collateral Ligament May Be More Cost-Effective and Result in Longer Playing Careers Than Nonoperative Management for High-Level Baseball Pitchers: A Decision-Analytic Markov Model-Based Analysis.

BACKGROUND: Nonoperative management versus early reconstruction for partial tears of the medial ulnar collateral ligament (MUCL) remains controversial, with the most common treatment options for partial tears consisting of rest, rehabilitation, platelet-rich plasma (PRP), and/or surgical intervention. However, whether the improved outcomes reported for treatments such as MUCL reconstruction (UCLR) or nonoperative management with a series of PRP injections justifies their increased upfront costs remains unknown. PURPOSE: To compare the cost-effectiveness of an initial trial of physical therapy alone, an initial trial of physical therapy plus a series of PRP injections, and early UCLR to determine the preferred cost-effective treatment strategy for young, high-level baseball pitchers with partial tears of the MUCL and with aspirations to continue play at the next level (ie, collegiate and/or professional). STUDY DESIGN: Economic and decision analysis; Level of evidence, 2. METHODS: A Markov chain Monte Carlo probabilistic model was developed to evaluate the outcomes and costs of 1000 young, high-level, simulated pitchers undergoing nonoperative management with and without PRP versus early UCLR for partial MUCL tears. Utility values, return to play rates, and transition probabilities were derived from the published literature. Costs were determined based on the typical patient undergoing each treatment strategy at the authors' institution. Outcome measures included costs, acquired playing years (PYs), and the incremental cost-effectiveness ratio (ICER). RESULTS: The mean total costs resulting from nonoperative management without PRP, nonoperative management with PRP, and early UCLR were $22,520, $24,800, and $43,992, respectively. On average, early UCLR produced an additional 4.0 PYs over the 10-year time horizon relative to nonoperative management, resulting in an ICER of $5395/PY, which falls well below the $50,000 willingness-to-pay threshold. Overall, early UCLR was determined to be the preferred cost-effective strategy in 77.5% of pitchers included in the microsimulation model, with nonoperative management with PRP determined to be the preferred strategy in 15% of pitchers and nonoperative management alone in 7.5% of pitchers. CONCLUSION: Despite increased upfront costs, UCLR is a more cost-effective treatment option for partial tears of the MUCL than an initial trial of nonoperative management for most high-level baseball pitchers.

High variability among surgeons in evaluation, treatment, and rehabilitation of medial ulnar collateral ligament injuries.

Hypothesis and/or Background: The incidence of elbow medial ulnar collateral ligament (MUCL) injuries has been increasing, leading to advances in surgical treatments. However, it is not clear that there is consensus among surgeons regarding diagnostic imaging, the indications for acute surgery and postoperative rehabilitation. The purpose of this study is evaluate surgeon variability in the presurgical, surgical, and postsurgical treatment of MUCL injuries regarding the imaging modalities used for diagnosis, indications for acute surgical treatment, and postoperative treatment recommendations for rehabilitation and return to play (RTP). Our hypothesis is that indications for acute surgical treatment will be highly variable based on MUCL tear patterns and that agreement on the time to RTP will be consistent for throwing athletes and inconsistent for nonthrowing athletes. Methods: A survey developed by 6 orthopedic surgeons with expertise in throwing athlete elbow injuries was distributed to 31 orthopedic surgeons who routinely treat MUCL injuries. The survey evaluated diagnostic and treatment topics related to MUCL injuries, and responses reaching 75% agreement were considered as high-level agreement. Results: Twenty-four surgeons responded to the survey, resulting in a 77% response rate. There is 75% or better agreement among surveyed surgeons regarding acute surgical treatment for distal full thickness tears, ulnar nerve transposition in symptomatic patients or with ulnar nerve subluxation, postoperative splinting for 1-2 weeks with initiation of rehabilitation within 2 weeks, the use of bracing after surgery and the initiation of a throwing program at 3 months after MUCL repair with internal brace by surgeons performing 20 or more MUCL surgeries per year. There were a considerable number of survey topics without high-level agreement, particularly regarding the indications for acute surgical treatment, the time to return to throwing and time RTP in both throwing and nonthrowing athletes. Discussion and/or Conclusion: The study reveals that there is agreement for the indication of acute surgical treatment of distal MUCL tears, duration of bracing after surgery, and the time to initiate physical therapy after surgery. There is not clear agreement on indications for surgical treatment for every MUCL tear pattern, RTP time for throwing, hitting and participation in nonthrowing sports.

Elbow anatomy in perspective of joint capsule and surrounding aponeuroses: a narrative review.

Background: Because of the proximity of several ligaments, aponeuroses, and capsule in the limited area of the elbow joint, the precise anatomy is difficult to understand. In the current narrative review, we focused on two anatomical perspectives: the capsular attachment and structures consisting of ligaments. Methods: Based on the previously performed studies regarding the elbow anatomy, a narrative review was prepared in terms of the capsular attachment and structures consisting of ligaments. Results: At the tip of the coronoid process, the joint capsule attaches roughly 6 mm distal to its tip with 6-12 mm length. On the lateral epicondyle of the humerus, the capsular attachment at the anterior part of the extensor carpi radialis brevis origin is narrower than the one distal to it. A single interpretation of the lateral collateral ligament is the capsulo-aponeurotic membrane, which is composed of the joint capsule intermingling with the supinator aponeurosis. The anterior bundle of the ulnar collateral ligament could be interpreted as the grossly separated collagenous structure from the tendinous complex, which is composed of the tendinous septum between the flexor digitorum superficialis and pronator teres muscle, the medial part of the brachialis muscle, and deep aponeurosis of the flexor digitorum superficialis muscle. Discussion: Based on these perspectives, ligaments could function as a "static-dynamic" stabilizer rather than a simple static one.

Elasticity assessment of flexor pronator muscles using shear wave elastography.

Background: The flexor pronator muscles (FPMs) have been thought as a dynamic stabilizer to protect the ulnar collateral ligament (UCL) from valgus stress during throwing motion. Thus, evaluation of the FPMs is important for preventing UCL injuries. Shear wave ultrasound elastography (SWE) is an imaging modality that quantifies tissue elasticity. The purpose of this study was to measure the tissue elasticities of healthy FPMs using SWE. Methods: We investigated 22 healthy men (mean age, 29 ± 6 years). The elasticities of the FPMs, including the pronator teres (PT), flexor digitorum superficialis (FDS), and flexor carpi ulnaris (FCU), were measured using SWE for each arm under two conditions: at rest (unloaded) and under valgus stress (loaded). The values obtained under different loading conditions were compared between both elbows. Results: The mean SWE values of the PT, FDS, and FCU for the dominant elbows were 22.4 ± 3.6, 22.8 ± 2.9, and 22.3 ± 3.4 kPa, respectively. The corresponding mean SWE values for the nondominant elbows were 24.2 ± 4.6, 23.1 ± 3.5, and 23.4 ± 3.5 kPa, respectively. The mean SWE values of the PT, FDS, and FCU at rest (unloaded) were 23.3 ± 4.2, 22.9 ± 3.2, and 22.9 ± 3.5 kPa, respectively. The corresponding mean SWE values under valgus stress (loaded) were 35.0 ± 6.2, 34.7 ± 5.3, and 31.9 ± 4.8 kPa, respectively. Conclusion: This noninvasive evaluation of the stiffness of the FPMs may provide clinically relevant data for the prevention of UCL injuries.

Twisting technique for ulnar collateral ligament reconstruction of the elbow: new possibilities toward enhancing the strength of autografts.

Background: Although the ulnar collateral ligament reconstruction procedure has been increasing in popularity annually owing to its stable postoperative outcomes, the number of revision surgeries following ulnar collateral ligament reconstruction has increased. The success of the initial reconstruction surgery and further improvement in the return-to-play rates of the initial surgery are crucial. In this study, we report on ulnar collateral ligament reconstruction using the twisting technique, which aims to enhance the strength of the graft (palmaris longus tendon) to improve return-to-play rates. Methods: We investigated the return-to-play rate and period in 60 cases (2016-2021) that underwent ulnar collateral ligament reconstruction using the twisting technique and 211 cases (2007-2019) that did not use the twisting technique. The twisting technique involved inserting the graft through the bone tunnel and then twisting the doubled tendon. Results: According to the Conway-Jobe scale, the twisting technique group had 98.3% excellent, 1.7% good, 0% fair, and 0% poor results, with a mean return-to-play period of 9.8 months. The non-twisting technique group had 86.7% excellent, 9.0% good, 1.9% fair, and 2.4% poor results, with a mean return-to-play period of 11.4 months. The two groups showed significant differences in return-to-play rate (P = .020) and period (P = .022). Conclusion: The clinical results of the twisting technique showed that the return-to-play rate of the twisting technique group was higher after than before the procedure, and the return-to-play period was shortened by more than 1 month. The twisting technique may improve the results of ulnar collateral ligament reconstruction surgery.

The pie-crust surgical technique for medial collateral ligament release: enhancing visualization of the medial compartment in knee arthroscopy.

This study presents a comprehensive surgical technique for performing a 'pie-crust' release of the medial collateral ligament (MCL) to enhance visualization of the medial compartment during arthroscopic knee procedures. The primary objective of this research is to improve the precision of diagnosis and treatment for injuries specifically affecting the posterior horn and posterior root of the medial meniscus. Arthroscopic knee procedures have become increasingly common in orthopedic surgery, offering the advantage of minimally invasive techniques for treating a wide range of knee conditions. However, accessing and visualizing the posterior structures within the medial compartment can be challenging. To overcome this limitation, the surgical technique presented in this study offers a systematic approach that includes patient positioning, precise identification of anatomical landmarks, and a detailed, step-by-step procedural description. The process begins with meticulous marking of anatomical landmarks to provide reference points. Precisely identifying the location for the MCL release is of utmost importance. This involves making needle punctures with guidance from arthroscopic visualization and applying valgus strain to the knee as necessary. One of the key advantages of this described surgical technique is its focus on safety and efficacy. Surgeons can work more confidently and precisely by reducing the risk of iatrogenic cartilage damage and facilitating access to the posterior structures within the medial compartment. Clinical outcomes from this approach have demonstrated consistently favorable results, leading to improved patient recovery and reduced complications. Furthermore, it is noteworthy that the postoperative use of a brace is not mandatory, adding to the appeal of this technique for both patients and surgeons. This surgical technique's enhanced visualization and optimized treatment outcomes make it a valuable tool in the arsenal of orthopedic surgeons specializing in knee arthroscopy. In conclusion, this study's surgical technique has the potential to significantly improve the diagnosis and treatment of patients with meniscal injuries in the medial compartment, ultimately leading to better clinical outcomes and patient satisfaction.

Secondary restraints in ACL reconstruction: State-of-the-art.

At-risk patients continue to experience a high likelihood of graft rupture after anterior cruciate ligament (ACL) reconstruction (ACLR). This narrative review seeks to provide the reader with an evidence-based synopsis of state-of-the-art concepts related to secondary restraint lesions, and how addressing them surgically might result in improved outcomes of ACLR.

The peak force to push a trial tibial insert into position cannot be used to select the correct thickness in total knee arthroplasty.

An objective of a total knee arthroplasty (TKA) is to restore native (i.e. healthy) function, and a crucial step is determining the correct insert thickness for each patient. If the insert is too thick, then stiffness results, and if too thin, then instability results. Two methods to determine the insert thickness are by manually assessing the joint laxity and by using a trial insert with goniometric markings that measures the internal-external rotation of the trial with respect to a mark on the femoral component. The former is qualitative and depends on the surgeon's experience and 'feel' and while the latter is quantitative, it can be used only with an insert with medial ball-in-socket conformity. An unexplored method is to measure the force required to push a trial insert into position. To determine whether this method has merit, the push force was measured in 30 patients undergoing unrestricted kinematically aligned TKA using an insert with ball-in-socket medial conformity, a flat lateral surface, and retention of the posterior cruciate ligament. During surgery, the surgeon determined three appropriate thicknesses to test from a selection ranging from 10 mm to 14 mm in 1 mm increments. The peak push forces going from an insert 1 mm thinner than the correct thickness as determined by an insert goniometer and from the correct thickness to 1 mm thicker were measured. Mean peak forces for the different insert thicknesses were 127 ± 104 N, 127 ± 95 N, and 144 ± 96 N for 1 mm thinner, correct, and 1 mm thicker, respectively, and did not differ (p = 0.3210). As a result, measurement of peak force during trial positioning of a tibial insert cannot be used to identify the correct thickness for all insert designs.

Load Sharing of the Deep and Superficial Medial Collateral Ligaments, the Effect of a Partial Superficial Medial Collateral Injury, and Implications on ACL Load.

BACKGROUND: Injuries to the deep medial collateral ligament (dMCL) and partial superficial MCL (psMCL) can cause anteromedial rotatory instability; however, the contribution of each these injuries in restraining anteromedial rotatory instability and the effect on the anterior cruciate ligament (ACL) load remain unknown. PURPOSE: To investigate the contributions of the different MCL structures in restraining tibiofemoral motion and to evaluate the load through the ACL after MCL injury, especially after combined dMCL/psMCL injury. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. Tibiofemoral kinematic parameters were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8-N·m valgus rotation, 4-N·m external tibial rotation (ER), 4-N·m internal tibial rotation, and a combined 89-N anterior tibial translation and 4-N·m ER for both anteromedial rotation (AMR) and anteromedial translation (AMT). The kinematic parameters of the 3 different MCL injuries (dMCL; dMCL/psMCL; dMCL/superficial MCL (sMCL)) were recorded and reapplied either in an ACL-deficient joint (load sharing) or before and after cutting the ACL (ACL load). The loads were calculated by applying the principle of superposition. RESULTS: The dMCL had the largest effect on reducing the force/torque during ER, AMR, and AMT in extension and the psMCL injury at 30° to 90° of knee flexion (P < .05). In a comparison of the load through the ACL when the MCL was intact, the ACL load increased by 46% and 127% after dMCL injury and combined dMCL/psMCL injury, respectively, at 30° of knee flexion during ER. In valgus rotation, a significant increase in ACL load was seen only at 90° of knee flexion. CONCLUSION: The psMCL injury made the largest contribution to the reduction of net force/torque during AMR/AMT at 30° to 90° of flexion. Concomitant dMCL/psMCL injury increased the ACL load, mainly during ER. CLINICAL RELEVANCE: If a surgical procedure is being considered to treat anteromedial rotatory instability, then the procedure should focus on restoring sMCL function, as injury to this structure causes a major loss of the knee joint's capacity to restrain AMR/AMT.

Effect of a Partial Superficial and Deep Medial Collateral Ligament Injury on Knee Joint Laxity.

BACKGROUND: Injuries to the medial collateral ligament (MCL), specifically the deep MCL (dMCL) and superficial MCL (sMCL), are both reported to be factors in anteromedial rotatory instability (AMRI); however, a partial sMCL (psMCL) injury is often present, the effect of which on AMRI is unknown. PURPOSE: To investigate the effect of a dMCL injury with or without a psMCL injury on knee joint laxity. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. The anterior cruciate ligament (ACL) was cut first and last in protocols 1 and 2, respectively. The dMCL was cut completely, followed by an intermediary psMCL injury state before the sMCL was completely sectioned. Tibiofemoral kinematics were measured at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8 N·m of valgus rotation (VR), 4 N·m of external tibial rotation, 4 N·m of internal tibial rotation, and combined 89 N of anterior tibial translation and 4 N·m of external tibial rotation for both anteromedial rotation (AMR) and anteromedial translation. The differences between subsequent states, as well as differences with respect to the intact state, were analyzed. RESULTS: In an ACL-intact or -deficient joint, a combined dMCL and psMCL injury increased external tibial rotation and VR compared with the intact state at all angles. A significant increase in AMR was seen in the ACL-intact knee after this combined injury. Cutting the dMCL alone showed lower mean increases in AMR compared with the psMCL injury, which were significant only when the ACL was intact in knee flexion. Moreover, cutting the dMCL had no effect on VR. The ACL was the most important structure in controlling anteromedial translation, followed by the psMCL or dMCL depending on the knee flexion angle. CONCLUSION: A dMCL injury alone may produce a small increase in AMRI but not in VR. A combined dMCL and psMCL injury caused an increase in AMRI and VR. CLINICAL RELEVANCE: In clinical practice, if an increase in AMRI at 30° and 90° of knee flexion is seen together with some increase in VR, a combined dMCL and psMCL injury should be suspected.

Psychological Impact and Posttraumatic Stress Disorder Symptomatology After Ulnar Collateral Ligament Injuries in Baseball Players.

Background: Significant psychological impact and prevalence of posttraumatic stress disorder (PTSD) have been well documented in patients sustaining anterior cruciate ligament injury. Purpose: To examine PTSD symptomatology in baseball players after sustaining elbow ulnar collateral ligament (UCL) injury. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Male baseball players of various competition levels (high school through Minor League Baseball [MiLB]) who underwent surgery for a UCL injury between April 2019 and June 2022 participated in the study. Before surgery, patients completed the Impact of Event Scale-Revised (IES-R) to assess PTSD symptomatology. Subgroup analysis was conducted according to level of play and player position. Results: A total of 104 male baseball players with a mean age of 19.4 years (range, 15-29 years) were included in the study; 32 players (30.8%) were in high school, 65 (62.5%) were in college, and 7 (6.7%) were in MiLB. There were 64 (61.5%) pitchers, 18 (17.3%) position players, and 22 (21.2%) 2-way players (both pitching and playing on the field). A total of 30 (28.8%) patients scored high enough on the IES-R to support PTSD as a probable diagnosis, and another 22 patients (21.2%) scored high enough to support PTSD as a clinical concern. Nineteen patients (18.3%) had potentially severe PTSD. Only 4 players (3.8%) were completely asymptomatic. Subgroup analysis revealed college players as significantly more symptomatic than high school players (P = .02), and 2-way players were found to be significantly less susceptible to developing symptoms of PTSD compared with pitchers (P = .04). Conclusion: Nearly 30% of baseball players who sustained a UCL injury qualified for a probable diagnosis of PTSD based on the IES-R. Pitchers and college athletes were at increased risk for PTSD after UCL injury compared with 2-way players and high school athletes, respectively.

Volar dislocation of the metacarpophalangeal joint of the thumb: open reduction and repair of the ulnar collateral ligament. A case report.

INTRODUCTION: metacarpophalangeal dislocations of the thumb are not very frequent injuries, it is necessary to know the anatomy of the region to know possible causes of interposition that prevent a closed reduction of this pathology. CASE PRESENTATION: we present the case of a 75-year-old woman with a post-traumatic metacarpophalangeal dislocation of the thumb that required open reduction and surgical repair. In this procedure, we performed reduction of the dislocation, mobilization of the interposed structures, repair of the capsule and reinsertion of the ulnar collateral ligament. The early mobilization protocol helped to obtain very good results. CONCLUSION: it is imperative to consider possible associated injuries during the acute phase to achieve optimal short, medium, and long-term outcomes for our patients. A comprehensive and proactive approach to diagnosis and treatment is vital in effectively addressing this pathology and minimizing its potential sequelae.

INTRODUCCIÓN: las luxaciones metacarpofalángicas del pulgar no son lesiones muy frecuentes, es necesario conocer la anatomía de la región para conocer posibles causas de interposición que impidan una reducción cerrada de esta patología. PRESENTACIÓN DEL CASO: presentamos el caso de una mujer de 75 años con luxación metacarpofalángica postraumática del pulgar que requirió reducción abierta y reparación quirúrgica. En este procedimiento realizamos reducción de la luxación, movilización de las estructuras interpuestas, reparación de la cápsula y reinserción del ligamento colateral cubital. El protocolo de movilización temprana ayudó a obtener muy buenos resultados. CONCLUSIÓN: es imperativo considerar posibles lesiones asociadas durante la fase aguda para lograr resultados óptimos a corto, mediano y largo plazo para nuestros pacientes. Un enfoque integral y proactivo del diagnóstico y tratamiento es vital para abordar eficazmente esta patología y minimizar sus posibles secuelas.