Suture tape augmentation of the lateral ulnar collateral ligament increases load to failure in simulated posterolateral rotatory instability.

PURPOSE: Simple elbow dislocations are accompanied with lateral ulnar collateral ligament ruptures. For persisting instability, surgery is indicated to prevent chronic posterolateral rotatory instability. After lateral collateral ligament (LCL) complex repair the repair is protected by temporary immobilization, limited range of motion and hinged bracing. Internal bracing is an operative alternative augmenting the LCL repair using non-absorbable suture tapes. However, the stability of LCL repair with and without additional augmentation remains unclear. The hypothesis was that LCL repair with additional suture tape augmentation would improve load to failure. Secondary goal of this study was to evaluate different humeral fixation techniques. A humeral fixation using separate anchors for the LCL repair and the augmentation was not expected to provide superior stability compared to using only one single anchor. METHODS: Twenty-one elbows were tested. A cyclic varus rotational torque of 0.5-3.5 Nm was applied in 90°, 60°, 30°, and 120° elbow flexion to the intact, torn, and repaired LCLs. The specimens were randomized into three groups: repair alone (group I), repair with additional internal bracing using two anchors (group II), repair using one humeral anchor (group III). A load-to-failure protocol was conducted. RESULTS: Load to failure was significantly higher in groups II (26.6 Nm; P = 0.017) and III (23.18 Nm; P = 0.038) than in group I (12.13 Nm). No significant difference was observed between group II and III. All specimens lost reduction after LCL dissection by a mean of 4.48° ± 4.99° (range 0.66-15.82). The mean reduction gain after repair was 7.21° ± 4.97° (2.70-21.23; mean over reduction, 2.73°). The laxity was comparable between the intact and repaired LCLs (n.s.), except for varus movements at 30° in group II (P = 0.035) and 30° (P = 0.001) and 120° in group III (P = 0.008) with significantly less laxity. Inserting the ulnar suture anchor showed failure in the thread in 10 cases. CONCLUSION: LCL repair with additional internal bracing yielded higher load to failure than repair alone. Repair with additional internal bracing for the humeral side using one anchor was sufficient. A higher primary stability would facilitate postoperative management and allow immediate functional treatment. Reducing the number of humeral anchors would save costs.

The moving valgus stress test produces more ulnar collateral ligament change in length during extension than during flexion: a biomechanical study.

HYPOTHESIS AND BACKGROUND: Injuries to the elbow medial ulnar collateral ligament (mUCL) pose a diagnostic challenge, with the moving valgus stress test (MVST) currently accepted as the gold-standard clinical test. This study sought to biomechanically evaluate the change in length of the ulnar collateral ligament (UCL) during flexion-extension using a null hypothesis that the mUCL will not experience a greater change in length with movement than with static loading. METHODS: Seven fresh-frozen human cadaveric elbows were tested with static and dynamic valgus stress. We measured (1) ligament length with a multi-camera optical system, (2) elbow flexion with an incremental encoder, and (3) valgus deviation with an electronic inclinometer. With a force applied to the wrist to simulate a clinical stress examination, the elbow was flexed and extended in a physiological elbow simulator to mimic the flexion and extension of the MVST. RESULTS: The simulated MVST produced more elongation of the UCL compared with static stress testing (P < .001). Ninety degrees of flexion produced the highest mean change, and the anterior and posterior bands demonstrated different length change characteristics. Comparison of dynamic flexion and extension showed a statistically significant difference in change in length: The mUCL reached the greatest change during extension, with the greatest changes during extension near 90° of flexion. DISCUSSION AND CONCLUSION: The MVST produces significantly more elongation of the mUCL than either a static test or a moving test in flexion. This study provides biomechanical evidence of the validity of the MVST as a superior examination technique for injuries to the UCL.

Importance of radar gun inclusion during return-to-throwing rehabilitation following ulnar collateral ligament reconstruction in baseball pitchers: a simulation study.

BACKGROUND: Rehabilitation following elbow ulnar collateral ligament reconstruction in baseball pitchers relies on a progression of pitching activities to ensure protection and gradual strengthening of the reconstructed ligament. The purpose of this study was to determine the medial elbow torque associated with pitches at various effort levels and determine whether radar gun assistance improves players' abilities to accurately match partial-effort pitches with true references based on maximum pitch velocity. METHODS: Thirty-seven healthy high school and collegiate baseball pitchers were included in this study. Participants were excluded if they were injured, recovering from injury, or otherwise not currently pitching at full effort. Pitch parameters were collected using a validated wearable sensor. Participants threw 5 pitches at 50%, 75%, and 100% subjective effort. Pitchers then threw 5 pitches at 50% maximum velocity and 75% maximum velocity, as measured by a radar gun. RESULTS: Thirty-seven pitchers completed this study. Pitches thrown at 50% and 75% partial effort were significantly faster and generated higher elbow torque than did pitches thrown at 50% and 75% velocity, respectively (P < .001). A 10% decrease in percentage of maximum velocity was associated with a 13% decrease in percentage of maximum elbow torque (ß coefficient = 1.3, R2 = 0.81, P < .001). CONCLUSION: Pitchers generate higher-than-intended forces when throwing at 50% and 75% effort during a subjective partial-effort throwing protocol. Use of a radar gun to guide partial-effort throwing during throwing rehabilitation programs may protect the reconstructed elbow from excess medial torque.

Biomechanical comparison of docking ulnar collateral ligament reconstruction with and without an internal brace.

BACKGROUND: Current ulnar collateral ligament (UCL) reconstruction techniques are substantially less stiff and demonstrate lower load to failure compared with the native UCL. UCL repair with the addition of an internal brace has demonstrated superior biomechanical performance compared with docking UCL reconstruction, but internal bracing has not yet been used in UCL reconstruction. HYPOTHESIS/PURPOSE: To evaluate the time-zero biomechanical performance of a UCL docking technique reconstruction with and without an internal brace compared with native UCL properties. METHODS: Twelve matched pairs of cadaveric elbows were dissected and fixed at 90° for biomechanical testing. A cyclic valgus torque protocol was used to test the anterior band of the UCL in native specimens. After native specimens were failed, palmaris grafts were used for a docking reconstruction with or without internal brace and were subjected to the same valgus torque test protocol. Torsional stiffness, ultimate failure torque, and ulnohumeral gapping were determined. RESULTS: Stiffness in UCL reconstructions using a standard docking technique (3.0 ± 0.4 N m/deg) were significantly less stiff (P < .001) than native UCL (4.0 ± 0.8 N m/deg), whereas reconstructions using an internal brace (3.6 ± 0.6 N m/deg) were not different (P = .120) compared with native. Ultimate failure torque for standard docking (18.3 ± 4.1 N m) was significantly lower (P < .001) than native UCL (36.9 ± 10.1 N m), whereas the internal brace samples (35.3 ± 9.8 N m) were not different (P = .772) than native. CONCLUSION: UCL reconstruction with an internal brace augmentation provides superior stiffness and time-zero failure strength when compared with the standard docking technique.

Side of Hamstring Harvest Does Not Affect Performance, Return-to-Sport Rate, or Future Hamstring Injuries After Ulnar Collateral Ligament Reconstruction Among Professional Baseball Pitchers.

BACKGROUND: Ulnar collateral ligament reconstruction (UCLR) is a successful procedure among professional baseball pitchers. It is unclear if hamstring tendon harvest side for UCLR affects the outcome or alters the risk for subsequent hamstring injury. HYPOTHESIS: Players with prior UCLR with ipsilateral (drive leg) hamstring autograft will have the same return-to-sport (RTS) rate and performance upon RTS but a higher number of subsequent lower extremity injuries than those with contralateral (landing leg) hamstring autograft. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All players between 2010 and 2015 who underwent UCLR with hamstring autograft were included. Surgical details of their procedures were recorded from operative reports. Outcomes for UCLR with hamstring autograft harvested from the drive leg were compared with UCLR with the graft harvested from the landing leg. RESULTS: Overall, 191 players underwent UCLR with hamstring autograft (drive leg, n = 58, 30%; landing leg, n = 133, 70%). The docking technique was more common in the drive leg group, while the figure-of-8 technique was more common in the landing leg group ( P > .001). More patients in the landing leg group underwent concomitant treatment of the ulnar nerve than the drive leg group ( P < .001). No difference existed in RTS rates or timing of RTS between groups. No differences in subsequent ipsilateral or contralateral hamstring injuries occurred between players who underwent UCLR with hamstring autograft from the drive leg or the landing leg ( P≥ .999 and P = .460, respectively). No difference in overall upper or lower extremity injury rates existed between groups (all P > .05), and no difference in performance metrics existed between groups upon RTS. CONCLUSION: No difference in RTS rate, performance upon RTS, or subsequent injury rates (hamstring, lower extremity, or upper extremity) existed between players who underwent UCLR with hamstring autograft whether the graft came from the drive or the landing leg.

The Stener Lesion and Complete Ulnar Collateral Ligament Injuries of the Thumb A Review.

A Stener lesion is a complete tear of the ulnar collateral ligament (UCL) from the thumb proximal phalanx at the level of the metacarpophalangeal (MCP) joint that is displaced superficial to the adductor pollicis aponeurosis, leading to interposition of the aponeurosis between the UCL and the MCP joint. The interposition of the adductor aponeurosis distinguishes the Stener lesion from other UCL injuries and impedes healing, thereby necessitating surgery. A thorough clinical examination, including valgus stress testing of the MCP joint, is crucial to the diagnosis. In cases where the clinical evaluation is equivocal, imaging studies including ultrasound or magnetic resonance can be performed. Acute Stener lesions can be treated with repair of the UCL primarily through direct suture, suture anchor, or pull-out suture techniques. Chronic injuries are treated with dynamic (via tendon transfer) or static (via grafting) reconstruction methods, while MCP arthrodesis or arthroplasty can be reserved for cases where MCP joint osteoarthritis is present. Overall, patient outcomes are generally good with operative treatment of Stener lesions. This article reviews the relevant anatomy and pathogenesis, clinical evaluation, diagnostic studies, management, outcomes, complications, and an illustrative case of Stener lesions and complete UCL injuries of the thumb.

Shear-wave elastography of the ulnar collateral ligament of the elbow in healthy volunteers: a pilot study.

OBJECTIVE: To estimate the intra-observer repeatability of shear wave elastography in the UCL of the elbow, and to compare shear wave velocities between dominant and non-dominant arms. MATERIALS AND METHODS: Twenty elbows in ten healthy volunteers were evaluated [five males, five females; mean age, 31.8 ± 10.3 years]. Shear wave velocity was measured on three separate days during the span of 1 week utilizing a linear 18-MHz transducer. Elastograms were obtained until ten ROIs were drawn, not drawing more than two ROIs on any elastogram. Elastograms were considered diagnostic if any portion of the UCL was colored in and free of boundary artifacts. Median velocity and interquartile range were recorded. A result was considered reliable if the IQR/median ratio of the ten measurements was < 0.3. RESULTS: IQR/median was < 0.3 in 88% of sessions, although in 28% of sessions fewer than 60% of elastograms were diagnostic. The ICC was 0.05 (95% CI; - 0.18-0.36; poor). Repeatability coefficient (95% limits of agreement) was 1.95 m/s (95% CI; 1.61-2.37 m/s). Mean velocity in dominant arms was 5.14 ± 0.53 m/s and 5.24 ± 0.39 m/s in non-dominant (p = 0.558). CONCLUSIONS: Mean shear wave velocity was similar between dominant and non-dominant arms. Although repeatability was poor as assessed by ICC, the repeatability coefficient may be a more useful indicator of clinical utility once shear wave velocities in diseased ligaments are explored. Future studies should therefore evaluate velocities in diseased ligaments and develop techniques to improve elastogram quality.

Fastball Velocity and Elbow-Varus Torque in Professional Baseball Pitchers.

CONTEXT: High loads in the elbow during baseball pitching can lead to serious injuries, including injuries to the ulnar collateral ligament. These injuries have substantial implications for individual pitchers and their teams, especially at the professional level of competition. With a trend toward increased ball velocity in professional baseball, controversy still exists regarding the strength of the relationship between ball velocity and elbow-varus torque. OBJECTIVE: To examine the relationship between fastball velocity and elbow-varus torque in professional pitchers using between- and within-subjects statistical analyses. DESIGN: Cross-sectional study. SETTING: Motion-analysis laboratory. PATIENTS OR OTHER PARTICIPANTS: Using the previously collected biomechanical data of 452 professional baseball pitchers, we performed a retrospective analysis of the 64 pitchers (52 right-hand dominant, 12 left-hand dominant; age = 21.8 ± 2.0 years, height = 1.90 ± 0.05 m, mass = 94.6 ± 7.8 kg) with fastball velocity distributions that enabled between- and within-subjects statistical analyses. MAIN OUTCOME MEASURE(S): We measured ball velocity using a radar gun and 3-dimensional motion data using a 12-camera automated motion-capture system sampling at 240 Hz. We calculated elbow-varus torque using inverse-dynamics techniques and then analyzed the relationship between ball velocity and elbow torque using both a simple linear regression model and a mixed linear model with random intercepts. RESULTS: The between-subjects analyses displayed a weak positive association between ball velocity and elbow-varus torque (R2 = 0.076, P = .03). The within-subjects analyses showed a considerably stronger positive association (R2 = 0.957, P < .001). CONCLUSIONS: When comparing 2 professional baseball pitchers, higher velocity may not necessarily indicate higher elbow-varus torque due to the confounding effects of pitcher-specific differences (eg, detailed anthropometrics and pitching mechanics). However, within an individual pitcher, higher ball velocity was strongly associated with higher elbow-varus torque.

Biomechanical Comparison of Ulnar Collateral Ligament Reconstruction With a Modified Docking Technique With and Without Suture Augmentation.

BACKGROUND: Throwing athletes with ulnar collateral ligament (UCL) injury and symptomatic valgus instability can expect to return to the same or higher level of play. Reconstruction with tendon graft is the dominant method of surgical treatment. Recent evidence suggests that spanning the joint with a suture anchored on both sides is biomechanically equivalent to reconstruction, with faster time to return to play. The authors developed a hybrid UCL reconstruction technique augmented with a suture brace to improve joint stability. PURPOSE/HYPOTHESIS: The purpose of this study was to biomechanically evaluate a hybrid reconstruction technique and compare its performance to reconstruction without augmentation. The authors hypothesized that (1) both groups would lose stability after the simulated tear and regain stability with treatment, (2) the suture augmentation would improve stability, and (3) the addition of the suture anchors near the bone tunnels would not decrease the strength of the hybrid reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: Ten matched pairs of cadaveric arms were dissected to expose the UCL. Each elbow was mounted on a test frame at 90° of flexion. A cyclic valgus rotational torque was applied to the humerus with the UCL in its intact state and repeated in its surgically torn state. Finally, each specimen received either a hybrid reconstruction with suture brace or a reconstruction and was again put through the cyclic protocol, followed by a valgus rotation load-to-fail protocol. RESULTS: Gap formation in the torn state for the reconstruction and hybrid reconstruction groups (0.9 ± 0.1 mm and 0.8 ± 0.1 mm, respectively) was significantly higher ( P = .009 and P = .0002) than in the intact state (0.6 ± 0.2 mm and 0.6 ± 0.3 mm, respectively). After the procedures, the hybrid group showed greater resistance to gapping ( P = .017) as compared with the reconstruction group (0.4 ± 0.2 mm and 0.6 ± 0.1 mm). During load to failure, no hybrid reconstructions failed from bone fracture or screw pullout. No statistical differences were found for failure torque ( P = .058) and stiffness ( P = .101). Gap at 10 N·m was significantly lower ( P = .014) for the hybrid reconstruction group than for the reconstruction group. CONCLUSION: The current study showed that hybrid reconstruction with suture bracing replicated the time-zero strength of traditional UCL reconstruction and may be more resistant to joint gapping during low cyclic load and load to failure. The combination of the bone tunnels and fixation screw holes did not appear to weaken the construct. CLINICAL RELEVANCE: This study demonstrated that reconstruction with suture bracing has important time-zero stability and strength as compared with the gold standard of UCL reconstruction. This technique may be useful for throwing athletes who need UCL reconstruction.

Following ulnar collateral ligament reconstruction, professional baseball position players return to play faster than pitchers, but catchers return less frequently.

BACKGROUND: Although much as been done to characterize trends of medial ulnar collateral ligament (UCL) reconstruction in pitchers, outcomes in position players (PPs) (non-pitchers) remain undefined in the current literature. METHODS: Three resources were combined to identify all known Major League Baseball and Minor League Baseball (MiLB) PPs who have ever undergone UCL reconstruction. A multitude of player and surgical variables were included. Trends over time were analyzed collectively, based on level of play, revision status (primary vs revision), and position. Additional comparisons were made with a known cohort of professional baseball pitchers having undergone UCL reconstruction. RESULTS: We identified 168 UCL reconstructions in professional PPs. The annual rate of primary UCL reconstruction rose significantly from 1984 to 2015 (P < .001), and the proportion of cases performed in MiLB PPs (vs Major League Baseball PPs) increased steadily (P < .001). Of PPs, 75.5% returned to play at any level at a mean of 342 days. Catchers demonstrated the lowest return-to-play (RTP) rate (58.6%) compared with infielders (75.6%) and outfielders (88.9%). The overall revision rate was low, at 4.8%. Compared with pitchers, PPs demonstrated a lower rate of RTP (75.5% for PPs vs 83.7% for pitchers, P = .040) but shorter RTP times for those able to return (342 days for PPs vs 435 days for pitchers, P < .001). CONCLUSIONS: The incidence of UCL reconstruction in PPs continues to rise, a trend that is significantly more pronounced at the MiLB level. Although PPs (particularly catchers) are less likely to return to professional baseball compared with pitchers, those who are able to RTP do so more rapidly.

Ulnar Collateral Ligament Reconstruction Past, Present, and Future Past, Present, and Future.

Shoulder and elbow injuries have been described in baseball players as early as the 1940s. Ulnar collateral ligament (UCL) tears have been recognized as a significant source of disability for baseball players and have been seen in increasing frequency as training regimens and level of play have become more intense and rigorous. Our understanding and treatment of these injuries have also evolved over time. This article summarizes the evolution of the treatment of UCL tears and discusses future directions for the treatment and prevention of these injuries.

The success of return to sport after ulnar collateral ligament injury in baseball: a systematic review and meta-analysis.

BACKGROUND: Ulnar collateral ligament injury (UCLI) has significantly increased in overhead sports during the past 2 decades. Differences in return to sport (RTS) and RTS at previous level (RTSP) after UCLI have not been differentiated. METHODS: A computer-assisted literature search of PubMed, CINAHL, Embase, and SportDiscus databases using keywords related to RTS for UCLI was implemented. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for study methodology. Quality assessment was conducted using a modified Downs and Black scale. RESULTS: A total of 22 retrospective, level 3b or 4, studies (n = 2289) qualified for analysis. Overall RTS proportion was 90% (95% confidence interval [CI], 86%-94%) and overall RTSP proportion was 79% (95% CI, 75%-84%), both with significant heterogeneity (P < .001, I2 = 74%-84%). RTS and RTSP proportions were 89% (95% CI, 83%-94%) and 78% (95% CI, 72%-83%) for Major League Baseball players, 91% (95% CI, 77%-99%) and 67% (95% CI, 52%-81%) for Minor League Baseball players, 95% (95% CI, 75%-100%) and 92% (95% CI, 82%-98%) for collegiate players, and 93% (95% CI, 81%-100%) and 83% (95% CI, 77%-89%) for high school players, respectively. Increased earned run average, walks, and hits per inning pitched, decreased innings pitched, and decreased fastball velocity were found after UCLI. CONCLUSION: Low-level, high-bias evidence demonstrates overall RTS proportion is higher than RTSP, regardless of treatment type for UCLI. Although RTS proportions remained consistent across various levels of play, RTSP proportions were lower in professional players, particularly Minor League Baseball compared with collegiate and high school players. Pitching performance significantly decreased postoperatively in most studies.

Performance outcomes after medial ulnar collateral ligament reconstruction in Major League Baseball positional players.

BACKGROUND: We sought to determine whether professional baseball positional players who underwent medial ulnar collateral ligament (MUCL) reconstruction demonstrate decreases in performance on return to competition compared with preoperative performance metrics and their control-matched peers. METHODS: Data for 35 Major League Baseball positional players who underwent MUCL reconstruction during 31 seasons were obtained. Twenty-six players met inclusion criteria. Individual statistics for the 2 seasons immediately before injury and the 2 seasons after injury included wins above replacement (WAR), on-base plus slugging (OPS), and isolated power (ISO). Twenty-six controls matched by player position, age, plate appearances, and performance statistics were identified. RESULTS: Of the 35 athletes who underwent surgery, 7 did not return to their preinjury level of competition (return to play rate of 80%). In comparing preinjury with postinjury statistics, players exhibited a significant decrease in plate appearances, at-bats, and WAR 2 seasons after injury but did not demonstrate declines in WAR 1 season after injury. Compared with matched controls, athletes who underwent MUCL reconstruction did not demonstrate significant decline in statistical performance, including OPS, WAR, and ISO, after return to play from surgery. Of all positional players, catchers undergoing surgery demonstrated lowest rates of return to play (56%) along with statistically significant decreases in home run rate, runs batted in, and ISO. CONCLUSION: Major League Baseball positional players undergoing MUCL reconstruction can reasonably expect to return to their preinjury level of competition and performance after surgery compared with their peers. Positional players return to play at a rate comparable to that of pitchers; catchers may experience more difficultly in returning to preinjury levels of play.

Cadaveric Biomechanical Analysis of 3 Lateral Ulnar Collateral Ligament Reconstructions.

OBJECTIVE: To biomechanically assess the angular stability provided by 3 techniques for reconstruction of the lateral ulnar collateral ligament. METHODS: Eight cadaveric elbows were tested with the lateral collateral ligament complex intact, disrupted from the origin at the lateral epicondyle, and reconstructed with 3 different techniques using ulnar bone tunnels: a suture "lasso" or palmaris longus tendon "lasso" both docked with a metal button at the origin, and a doubled-over palmaris longus tendon docked with metal buttons at both the origin and ulnar insertion. Elbows were tested with a physiologic elbow simulator, and varus angular position was quantified with an optical tracking system. Statistical analysis was performed using a repeated measures analysis of variance test to determine whether significance existed, and a Tukey post hoc analysis to compare statistical difference between native, disrupted, and repair states. RESULTS: There was a statistically significant difference between all repairs and the disrupted state (P < 0.05). The varus angulation after the repairs showed that the suture reconstruction was closest to the native case. The tendon reconstructions were similar to each other but less similar to the native elbow. Quantitatively, the suture reconstruction was within an average of 0.86 degrees of the native elbow throughout range of motion. CONCLUSIONS: A suture reconstruction was most similar to a native elbow, but both tendon reconstructions significantly improved angular stability under varus gravitational loads.

The influence of sex and trauma impact on the rupture site of the ulnar collateral ligament of the thumb.

PURPOSE AND HYPOTHESIS: Although sex- and gender-specific analyses have been gaining more attention during the last years they have rarely been performed in orthopaedic literature. The primary purpose of this study was to investigate whether for injuries of the UCL the specific location of the rupture is influenced by sex. A secondary study question addressed the sex-independent effect of trauma intensity on the rupture site of the UCL. METHODS: This study is a retrospective analysis of all patients with either a proximal or distal bony avulsion or with a mid-substance tear or ligament avulsion of the UCL treated surgically between 1992 and 2015 at two level-I trauma centres. Trauma mechanisms leading to the UCL injury were classified into the following categories: (1) blunt trauma (i.e., strains), (2) low-velocity injuries (e.g., fall from standing height, assaults), and (3) high-velocity injuries (e.g., sports injuries, motor vehicle accidents). After reviewing the surgical records, patients were divided into three groups, depending upon the ligament rupture site: (1) mid-substance tears, (2) proximal ligament or bony avulsions and (3) distal ligament or bony avulsions. Dependencies between the specific rupture site and the explanatory variables (sex, age, and trauma intensity) were evaluated using χ2 test and logistic regression analysis. RESULTS: In total, 1582 patients (1094 males, 488 females) met the inclusion criteria. Mean age was 41 years (range: 9-90 years). Taking into account the effects of sex on trauma intensity (p<0.001) and of trauma intensity on rupture site (p<0.001), mid-substance tears occurred more frequently in women, whereas men were more prone to distal ligament or bony avulsions (p<0.001). In other words, sex and rupture site correlated due to the effects of sex on trauma intensity and of trauma intensity on rupture site, but taking into account those effects there still was a significant effect of sex on rupture site. CONCLUSIONS: The results of this study demonstrate that with regression analysis both sex and trauma intensity allow to predict rupture site in UCL injuries.

[Lateral ulnar collateral ligament reconstruction : A biomechanical analysis of posterolateral rotatory instability of the elbow]. / Laterale ulnare Kollateralbandplastik : Biomechanische Untersuchung zur posterolateralen Rotationsinstabilität des Ellenbogens.

BACKGROUND: Chronic posterolateral rotatory instability (PLRI) of the elbow is the result of an insufficiency of the lateral collateral ligament (LCL). Lateral ulnar collateral ligament (LUCL) reconstruction represents a well-established treatment method for PLRI. However, recurrent instability remains a problem. OBJECTIVES: The goal of this in-vitro study was to evaluate the posterolateral rotatory stability of the intact elbow, after sectioning of the LCL and after LUCL reconstruction with a triceps tendon autograft and double BicepsButton(TM) fixation. MATERIALS AND METHODS: Posterolateral rotatory stability of 6 fresh-frozen elbow specimens at a torque of 3 Nm was analyzed at 0, 45, 90 and 120° of flexion for the intact LCL, after sectioning of the LCL and after LUCL reconstruction. Moreover, cyclic loading (1000 cycles) of the intact specimens and after LUCL reconstruction was performed. RESULTS: The intact LCL and the LUCL reconstruction provided equal primary stability (0.250 ≤ p ≤ 0.888). Sectioning of the LCL significantly increased PLRI (p < 0.001). The stability of the intact specimens and after LUCL reconstruction did not differ after cyclic loading (p = 0.218). During cyclic loading, posterolateral rotation increased significantly more after LUCL reconstruction (3.2 ± 0.8°) when compared to the native LCL (2.0 ± 0.7°, p = 0.020). CONCLUSIONS: LUCL reconstruction with BicepsButton(TM) fixation provides comparable stability to the native LCL. Further clinical results are necessary to evaluate whether this technique can decrease the complication rate.

Medial Epicondyle Fractures in the Pediatric Overhead Athlete.

The medial epicondyle serves as the proximal attachment of the medial ulnar collateral ligament and the origin of the flexor pronator musculature and as such it is responsible for resisting the main static and dynamic restraints to valgus force at the elbow. Fractures through the physis in the developing elbow are common and treatment remains controversial. Biomechanical modeling predicts that anterior should be the direction of greatest displacement. Anatomic considerations predict that anterior displacement should have the greatest effect on elbow stability and range of motion making the ulnar collateral ligament too loose in flexion and too tight in extension and potentially leading to valgus laxity in flexion and a block to full extension. In the elite overhead athlete, where elbow stability is critical both for sports performance and the long-term health of the elbow, assessment of anterior displacement is thus theoretically an important consideration. Standard radiographic views cannot adequately assess anterior displacement. Specialized radiographs and 3-dimensional modalities such as computerized tomography and magnetic resonance imaging can adequately assess anterior displacement and in the overhead athlete can sometimes aid in the decision-making process. Here, we present a review of the current literature and the rationale for a treatment algorithm for medial epicondyle fractures in the skeletally immature overhead athlete.