Elbow Medial Ulnar Collateral Ligament Research Articles

Rehabilitation Protocols in Elbow Medial Ulnar Collateral Ligament Injuries: A Systematic Review of Articles Published in the Last 20 Years.

Elbow medial ulnar collateral ligament (UCL) injuries have become increasingly common in athletes. Despite this, rehabilitation protocols appear to vary drastically, which may explain the clinical equipoise regarding optimal management. This systematic review reports rehabilitation characteristics reported after UCL injuries and compares reported outcomes based on early versus delayed rehabilitation. Our search utilized PubMed/MEDLINE, Embase, Web of Science, and Cochrane to identify all articles on UCL rehabilitation published between January 1, 2002 and October 1, 2022. Studies in English with ≥5 patients that reported rehabilitation protocols for UCL injuries were evaluated. Systematic review. Level 4. Data included sample characteristics, time to achieve physical therapy milestones, outcome scores, and return-to-play (RTP) rate and timing. Our review included 105 articles with a total of 15,928 elbows (98% male; weighted mean age, 23 years; follow-up, 47 months), with 15,077 treated operatively and 851 treated nonoperatively. The weighted mean time patients spent adhering to nonweightbearing status was 42 days. The mean time until patients were given clearance for active range of motion (ROM) 15 days, full ROM 40 days, and elbow strengthening exercises 32 days. The mean time until all restrictions were lifted was 309 days. The mean time to begin a throwing program was 120 days. Across all rehabilitation characteristics, protocols for patients undergoing nonoperative management started patients on rehabilitation earlier. After UCL reconstruction, earlier active ROM (≤14 days), elbow strengthening (≤30 days), no restrictions (≤180 days), and throwing (≤120 days) postoperatively led to earlier RTP without a negative effect on functional outcome scores. Current literature provides a spectrum of protocols for elbow UCL rehabilitation, regardless of management. Nonoperative patients began ROM activities, strengthening, and throwing programs sooner than operative patients, and earlier milestones led to earlier RTP.

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

BackgroundThe 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. Hypothesis/PurposeThe 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. 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 return to play will be consistent for throwing athletes and inconsistent for non-throwing athletes. MethodsA survey developed by six orthopedic surgeon 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. ResultsTwenty-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 return to play in both throwing and non-throwing athletes. ConclusionThe 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, return to play time for throwing, hitting and participation in non-throwing sports.

Does proximal versus distal injury location of the medial ulnar collateral ligament of the elbow differentially impact elbow stability? An ultrasound-guided and robot-assisted biomechanical study.

The location (proximal vs. distal) of elbow medial ulnar collateral ligament (MUCL) tears impacts clinical outcomes of nonoperative treatment. The purposes of our study were to (1) determine whether selective releases of the MUCL could be performed under ultrasound (US) guidance without disrupting overlying soft tissues, (2) assess the difference in medial elbow stability for proximal and distal releases of the MUCL using stress US and a robotic testing device, and (3) elucidate the flexion angle that resulted in the greatest amount of medial elbow laxity after MUCL injury. Sixteen paired, fresh-frozen elbow specimens were used. Valgus laxity was evaluated with both US and robotic-assisted measurements before and after selective MUCL releases. A percutaneous US-guided technique was used to perform proximal MUCL releases in 8 elbows and to perform distal MUCL releases in their matched pairs. The robot was used to determine the elbow flexion angle at which the maximum valgus displacement occurred for both proximally and distally released specimens. Open dissection was then performed to assess the accuracy of the percutaneous releases. Percutaneous US-guided releases were successfully performed in 15 of 16 specimens. The proximal release resulted in greater valgus angle displacement (11°±2°) than the distal release (8°±2°) between flexion angles of 30° and 70° (P<.0001 at 30°, P<.0001 at 40°, P=.001 at 50°, P=.005 at 60°, and P=.020 at 70°). Valgus displacement between release locations did not reach the level of statistical significance between 80° and 120° (P=.051 at 80°, P=.131 at 90°, P=.245 at 100°, P=.400 at 110°, and P=.532 at 120°). When we compared the values for the mean increase in US delta gap (stressed - supported state) from before to after MUCL release, the proximally released elbows had larger increases than the distally released elbows (5.0 mm proximal vs. 3.7 mm distal, P=.032). After MUCL release, maximum mean valgus displacement occurred at 49° of flexion. US-guided selective releases of the MUCL can be performed reliably without violating the overlying musculature. Valgus instability is not of greater magnitude for distal releases when compared with proximal releases. This findings suggests there must be alternative factors to explain the difference in clinical prognosis between distal and proximal tears. The observed flexion angle for maximum valgus laxity could have important implications for elbow positioning during US or fluoroscopic stress examination, as well as surgical repair or reconstruction of the MUCL.

Changes in elbow joint contact area in symptomatic valgus instability of the elbow in baseball players

The aim of this study was to evaluate the joint contact area of the dominant side and that of the non-dominant side without valgus instability in symptomatic pitchers. Ten symptomatic elbow medial ulnar collateral ligament (UCL) deficient baseball pitchers participated in this study. Computed tomography (CT) data from the dominant and non-dominant elbows were obtained with and without elbow valgus stress. The CT imaging data of each elbow joint were reconstructed using a 3D reconstruction software package, and the radiocapitellar and ulnohumeral joint contact areas were calculated. The center of the contact area and the translation from the position without stress to the position with valgus stress were also calculated. With elbow valgus stress, the contact area changed, and the center of the radiocapitellar joint contact area translated significantly more laterally in the dominant elbow than in the non-dominant elbow (p = 0.0361). In addition, the center of the ulnohumeral joint contact area translated significantly more posteriorly in the dominant elbow than in the non-dominant elbow (p = 0.0413). These changes in contact areas could be the reason for cartilage injury at the posterior trochlea in pitchers with UCL deficiency.

Is Allograft Reconstruction of the Medial Ulnar Collateral Ligament of the Elbow a Viable Option for Nonelite Athletes? Outcomes at a Mean of 8 Years.

Background:The rate of elbow medial ulnar collateral ligament (MUCL) injury and surgery continues to rise steadily. While authors have failed to reach a consensus on the optimal graft or anchor configuration for MUCL reconstruction, the vast majority of the literature is focused on the young, elite athlete population utilizing autograft. These studies may not be as applicable for the “weekend warrior” type of patient or for young kids playing on high school leagues or recreationally without the intent or aspiration to participate at an elite level.Purpose:To investigate the clinical outcomes and complication rates of MUCL reconstruction utilizing only allograft sources in nonelite athletes.Study Design:Case series; Level of evidence, 4.Methods:Patient records were retrospectively analyzed for individuals who underwent allograft MUCL reconstruction at a single institution between 2000 and 2016. A total of 25 patients met inclusion criteria as laborers or nonelite (not collegiate or professional) athletes with a minimum of 2 years of postoperative follow-up. A review of the medical records for the included patients was performed to determine survivorship free of reoperation, complications, and clinical outcomes with use of the Summary Outcome Determination (SOD) and Timmerman-Andrews scores. Statistical analysis included a Wilcoxon rank-sum test to compare continuous variables between groups with an alpha level set at .05 for significance. Subgroup analysis included comparing outcome scores based on the allograft type used.Results:Twenty-five patients met all inclusion and exclusion criteria. The mean time to follow-up was 91 months (range, 25-195 months), and the mean age at the time of surgery was 25 years (range, 12-65 years). There were no revision operations for recurrent instability. The mean SOD score was 9 (range, 5-10) at the most recent follow-up, and the Timmerman-Andrews scores averaged 97 (range, 80-100). Three patients underwent subsequent surgical procedures for ulnar neuropathy (n = 2) and contracture (n = 1), and 1 patient underwent surgical intervention for combined ulnar neuropathy and contracture.Conclusion:Allograft MUCL reconstruction in nonelite athletes demonstrates comparable functional scores with many previously reported autograft outcomes in elite athletes. These results may be informative for elbow surgeons who wish to avoid autograft morbidity in common laborers and nonelite athletes with MUCL incompetency.

The History and Evolution of Elbow Medial Ulnar Collateral Ligament Reconstruction: from Tommy John to 2020.

The purpose of this review article is to discuss the evolution of surgical reconstruction of the anterior bundle of the UCL, otherwise known as Tommy John surgery, from Dr. Jobe's initial description in 1986 to present day. In particular, the unique changes brought forth by each new surgical technique, and the reasons that these changes were implemented, are highlighted. The incidence of UCL reconstruction surgery continues to increase significantly, particularly in the 15- to 19-year-old age group. New anatomic understanding of the anterior bundle of the UCL, including the importance of the central fibers and the broad and tapered ulnar insertion, may affect optimal UCL reconstruction techniques in the future. Although return to play rates are generally quite high (80-95%), the mean time to return to play (typically 12-18months for pitchers) is longer than desired. Accordingly, many authors feel that there remains room for improvement in the treatment of this common injury. The Tommy John surgery has evolved in many ways with the development of novel techniques over the last 35years. Currently, overhead throwing athletes undergoing UCL reconstruction have high return to play and low complication rates. Future modifications to the surgery may aim to further improve outcomes and, more importantly, expedite the length of postoperative rehabilitation.

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

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. 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. 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. 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.

Evaluation of elbow medial ulnar collateral ligament on the comparison MRI with ultrasonography in professional baseball pitchers

Evaluation of elbow medial ulnar collateral ligament on the comparison MRI with ultrasonography in professional baseball pitchers

Elbow Medial Ulnar Collateral Ligament chronic isolated insufficiency: anatomical M-UCL reconstruction technique and clinical experience in a mid-term follow-up.

This study aims to clinically evaluate, at mid-term follow-up, a group of patients treated by the senior author in the last 6years with our anatomical double-bundle reconstruction surgical technique for the medial ulnar collateral ligament (M-UCL) insufficiency. In this study, we included only patients affected by chronic valgus elbow instability, diagnosed with an accurate clinical evaluation combined with an MRI, without associated fractures that had been surgically treated in the past and without additional instability detected during the first checkup and in the preoperative evaluation under anesthesia. The nine patients enrolled were operated by the senior author between 2011 and 2014 (from 16 to 49years old at surgery, all amateur sportsmen). The average follow-up is 4years (47.6months). The values of the range of movement were recorded and compared. Pain assessment was performed using the VAS scoring system. The recovery of daily activities was evaluated through the validated MEPS and Quick-DASH score scales. All patients underwent an X-ray in two standard projections and a preoperative and follow-up MRI. The recovery of the range of motion was complete in six cases. The remaining three patients had minor loss of extension. None of the patients reported flexion deficits nor pronation-supination at follow-up. All patients achieved subjectively perceived stability and clinically objectified stability at follow-up. Five patients referred a total lack of pain at follow-up. Seven patients achieved full marks in the Mayo Elbow Performance Score and an excellent improvement in the Quick-DASH score. Excellent functional results indicate that M-UCL isolated reconstruction with autologous hamstrings described in this study is a reliable and replicable technique with a reduced incidence of complications. Resuming sports is consistently successful in our patients.

Biomechanical analysis of elbow medial ulnar collateral ligament tear location and its effect on rotational stability

Recent anatomic and clinical studies have shown that the location of the injury to the elbow ulnar collateral ligament (UCL) is an important variable in deciding on surgical intervention; however, no studies have evaluated these findings biomechanically. This study tested 16 intact elbow specimens. Valgus torques of 2.5 and 5 Nm were applied to the elbow at various flexion angles, and the resulting valgus angles were measured. The valgus angles were applied to the elbows in their intact states and again after partial and complete cuts were made on the proximal and distal insertions of the UCL. Resulting valgus torques were measured, and stiffness was calculated for each elbow flexion angle. Unpaired t tests were used to evaluate the effects of cut location and flexion angle on joint rotational stability and stiffness. The posterior-distal insertion contributed the most to stability. At valgus angles generated from 2.5 Nm intact torques, the posterior-distal insertions contributed to 51% ± 26% (P < .03) intact rotational stability, and at valgus angles generated from 5 Nm intact torques, the posterior-distal insertions contributed to 41% ± 17% (P < .02) intact rotational stability. For overall stiffness, the posterior-distal insertions contributed to 31% ± 12% (P < .045) intact stiffness. Overall, the posterior distal insertion of the UCL contributed most to rotational stability and stiffness of the medial elbow when subjected to valgus stress at 90° and 120° of elbow flexion. At higher elbow flexion angles, the posterior insertions contributed more to stability, whereas the anterior insertions had a greater effect at lower flexion angles.

The Effect of Humeral and Ulnar Tunnel Placement on Achieving UCL Graft Isometry

Objectives:The elbow medial ulnar collateral ligament (UCL) is frequently injured in throwing athletes, most commonly baseball pitchers. When conservative management fails, surgical intervention can allow the athlete to return to sport. While extensive research has been devoted to UCL graft incorporation and outcomes based on varying surgical techniques, there is a paucity of literature available addressing optimal bone tunnel placement in achieving medial UCL graft isometry. The purpose of this study is to assess the effect of humeral and ulnar bone tunnel placement on achieving UCL graft isometry through elbow range-of-motion.Methods:Ten fresh-frozen cadaveric upper extremities were dissected to expose the native UCL in its entirety. Three equidistant humeral and ulnar tunnels were created at each UCL footprint. Suture was passed between nine possible tunnel combinations for each elbow affixed to an isometry guage. Each elbow was moved through a 120-degree arc of motion for each tunnel combination at 0, 30, 60, 90, and 120 degrees. Measured changes in isometry gauge tension were recorded and analyzed using one-way analysis of variance (ANOVA) with Tukey’s HSD for pairwise comparisons. A p-value of 0.05 was used to determine significance for all tests.Results:There was an overall significant effect (p < 0.0001) of tunnel placement at all degrees of flexion measured. Pairwise comparisons revealed increases in displacement between the central and posterior tunnel positions of the medial epicondyle, with significant differences (p=0.0009) occurring when paired with both the central and posterior aspect of the sublime tubercle. Profound differences (p < 0.0001) were noted between the anterior and posterior humeral tunnel positions. No significant differences noted between ulnar tunnel locations at any humeral location. Figure 1: Tunnel placement in the central part of the medial epicondyle (Centralepi) was generally the most isometric grouping, with Centralepi - Anteriortub being the most isometric combination of all. Data are represented as mean +/- SEM.Conclusion:Isometric graft placement of the medial elbow UCL is undoubtedly dependent upon optimal tunnel placement and even slight deviations from the native centroid at either the medial epicondyle or sublime tubercle can possibly lead to early graft failure or abnormal joint kinematics. This information can aid surgeons in performing isometric single bone tunnel UCL reconstruction or repair procedures in the future.

Correlation Between Quality of Evidence and Number of Citations in Top 50 Cited Articles on Elbow Medial Ulnar Collateral Ligament Surgery.

Background:Several studies have analyzed the most cited articles in shoulder, elbow, pediatrics, and foot and ankle surgery. However, no study has analyzed the quality of the most cited articles in elbow medial ulnar collateral ligament (UCL) surgery.Purpose:To (1) identify the top 50 most cited articles related to UCL surgery, (2) determine whether there was a correlation between the top cited articles and level of evidence, and (3) determine whether there was a correlation between study methodological quality and the top cited articles.Study Design:Systematic review.Methods:Web of Science and Scopus online databases were searched to identify the top 50 cited articles in UCL surgery. Level of evidence, number of times cited, year of publication, name of journal, country of origin, and study type were recorded for each study. Study methodological quality was analyzed for each article with the Modified Coleman Methodology Score (MCMS) and the Methodological Index for Non-randomized Studies (MINORS). Correlation coefficients were calculated.Results:The 50 most cited articles were published between 1981 and 2015. The number of citations per article ranged from 20 to 301 (mean ± SD, 71 ± 62 citations). Most articles (92%) were from the United States and were level 3 (16%), level 4 (58%), or unclassified (16%) evidence. There were no articles of level 1 evidence quality. The mean MCMS and MINORS scores were 28.1 ± 13.4 (range, 3-52) and 9.2 ± 3.6 (range, 2-19), respectively. There was no significant correlation between the mean number of citations and level of evidence or quality (rs = –0.01, P = .917), MCMS (rs = 0.09, P = .571), or MINORS (rs = –0.26, P = .089).Conclusion:The top 50 cited articles in UCL surgery constitute a low level of evidence and low methodological quality, including no level 1 articles. There was no significant correlation between the mean number of citations and level of evidence or study methodological quality. However, weak correlations were observed for later publication date and improved level of evidence and methodological quality.

Elbow medial ulnar collateral ligament reconstruction: Clinical relevance and the docking technique

Elbow ulnar collateral ligament (UCL) reconstruction has become the standard of care for the throwing athlete with a symptomatic ruptured or insufficient ligament and the desire to resume competitive play. Since Jobe's initial description of UCL reconstruction, the technique has evolved. A novel modification was the "docking" technique developed by Altchek. Subsequently, the docking technique as originally described was slightly modified. Arthroscopy is no longer routinely performed, and in some cases, a 3-strand graft is used. We treated 21 overhand athletes with clinical and radiographic evidence of UCL insufficiency with ligament reconstruction using a modified version of the docking technique using a 3-strand graft. There were 5 professional, 11 college, and 5 high school baseball players in the reconstructed group. Athletes were evaluated postoperatively by use of the Conway Scale. Of the 21 patients who underwent the modified docking technique with a three-strand graft, 19 (90%) had excellent results. There were 2 good results and no complications. UCL reconstruction can successfully treat athletes with UCL insufficiency. Several different reconstruction techniques have been described. By use of the docking and modified docking techniques, good to excellent results can be achieved in the majority of cases with a low complication rate.

Revision Surgery for Failed Elbow Medial Collateral Ligament Reconstruction

Background Although excellent results can be achieved in up to 90% of primary elbow medial ulnar collateral ligament reconstructions, retears of the ligament have been reported. As the number of primary reconstructions continues to increase, one could expect a commensurate increase in the number of revision medial collateral ligament reconstructions performed. Hypothesis Given the difficulty associated with revision procedures, the complication rate relative to primary reconstructions would increase while the percentage of athletes returning to their previous level of play would decrease. Study Design Case series; Level of evidence. 4. Methods This was a retrospective review of 15 patients who underwent revision surgery for retear of a reconstructed elbow medial collateral ligament. All patients had undergone previous elbow medial collateral ligament reconstruction and had new history and physical examination findings consistent with medial collateral ligament injury. Twelve subjects were professional baseball players and 3 were college-level players at the time of their revision procedure. Patients were evaluated at a minimum of 2 years after revision surgery. Outcomes were classified using the Conway scale. Results Average time to revision was 36 months. The technique used in the revision was the Jobe technique in 11 cases, DANE TJ in 3, and primary repair in 1. Thirty-three percent (5/15 excellent) returned to their previous level of play for at least 1 season. Additionally, there were 4 good, 2 fair, and 4 poor results. The ligament repair had a good outcome. Forty percent (6/15) of Patients had complications, 1 of whom required a subsequent surgery (lysis of adhesions). One subject experienced a retear of the medial collateral ligament. Conclusion The rate of return to play after revision medial collateral ligament surgery is much lower than after primary reconstruction. As was expected, the complication rate of revision surgery is higher as well. This study should help physicians when counseling baseball players who suffer retears of their medial collateral ligament.

Biomechanical Evaluation of 2 Techniques for Ulnar Collateral Ligament Reconstruction of the Elbow

Background Elbow medial ulnar collateral ligament tears often result in pain and instability that may be career threatening in overhead-throwing athletes. Surgical reconstruction is frequently chosen to treat this injury. Ulnar collateral ligament reconstruction as described by Jobe is the most commonly used technique. Testing of this construct has not demonstrated that the biomechanical parameters of the native ligament are restored. A more recent construct, the docking technique, may more reliably reproduce these factors. Hypothesis Increasing the number of strands of palmaris longus tendon graft used in ulnar collateral ligament reconstruction and tensioning them using the docking technique result in a construct with improved biomechanical parameters as compared with the Jobe technique. Study Design Controlled laboratory study. Methods Thirty-three fresh-frozen human cadaveric elbows were randomized into 3 subgroups: Jobe (11), docking (12), and native (10). The Jobe and docking groups underwent reconstruction using their described palmaris tendon graft constructs. The ulnar collateral ligament was left intact in the native group. Elbows were potted and tested using a servohydraulic materials testing machine to apply a valgus moment at 30° of elbow flexion. Maximal moments to failure, stiffness, and strain at maximal moment and with a 3 N·m force applied were determined using a 2-camera motion analysis system to track reflective markers spanning the site. Results The docking (14.3 N·m) and native (18.8 N·m) subgroups resulted in higher maximal moment to failure than did the Jobe (8.9 N·m) subgroup (P <. 001). There was no significant difference between native and docking groups (P >. 05). Native ligaments were stiffer (301.4 N·m) than were Jobe (74.3 N·m) or docking (80.8 N·m; P <. 001). Native ligaments demonstrated lower strain at maximal force (0.087 mm/mm) and 3 N·m forces (0.030 mm/mm) than did the Jobe (0.198/0.057 mm/mm) or docking (0.287/0.042 mm/mm) subgroups. There was no difference in stiffness or strain between the Jobe and docking subgroups (P >. 05). Conclusion Neither technique reproduced the biomechanical profile of the native ulnar collateral ligament; the findings of this study suggest that the docking construct may offer initial biomechanical advantage over the Jobe construct.

Elbow Medial Ulnar Collateral Ligament Insufficiency Alters Posteromedial Olecranon Contact

Background The effect of elbow medial ulnar collateral ligament injury on posteromedial compartment contact is unknown. Hypothesis Medial ulnar collateral ligament injury causes altered contact area and pressure in the posteromedial compartment of the elbow. Study Design Controlled laboratory study. Methods Seven elbow cadaveric specimens were tested in an apparatus that positioned the elbow at 30° and 90° of flexion. Partial and full tears were simulated by releasing the medial ulnar collateral ligament. Pressure-sensitive film was placed in the posteromedial compartment for each condition. Valgus torques of 1.25 and 2.0 N.m were applied for each ligament condition, and kinematic data were obtained at each flexion angle using a 3-dimensional digitizer. Results Both ligament condition and valgus load had significant effects on contact area and pressure (P < .05). For a given load and flexion angle, the contact area decreased and the pressure increased with increasing medial ulnar collateral ligament insufficiency. Within these trends, statistical significance was found at 30° of elbow flexion for both area and pressure (P < .05); at 90° of elbow flexion, increasing medial ulnar collateral ligament insufficiency did not significantly affect contact area or pressure (P > .05). Discussion Medial ulnar collateral ligament insufficiency alters contact area and pressure between the posteromedial trochlea and olecranon and helps explain the development of posteromedial osteophytes.