Does posteromedial chondromalacia reduce rate of return to play after ulnar collateral ligament reconstruction?

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

CONTEXT

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.

OBJECTIVE

This systematic review reports rehabilitation characteristics reported after UCL injuries and compares reported outcomes based on early versus delayed rehabilitation.

DATA SOURCES

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.

STUDY SELECTION

Studies in English with ≥5 patients that reported rehabilitation protocols for UCL injuries were evaluated.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Data included sample characteristics, time to achieve physical therapy milestones, outcome scores, and return-to-play (RTP) rate and timing.

RESULTS

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.

CONCLUSION

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.

Non-Medial Ulnar Collateral Ligament Elbow Pathology in the Thrower: Valgus Extension Overload, Osteochondritis Dissecans, Olecranon Stress Fracture, and Ulnar Nerve

Injury rates in baseball players reach as high as 5.8 per 1000 at the professional level. Recent data have singled out the elbow as the leading cause of injured list necessitating injuries and the costliest injury location in professional baseball. While the medial ulnar collateral ligament (MUCL) has gained the largest notoriety in this population, elbow injury in the thrower occurs as a spectrum of pathologies. These pathologies may encompass other injuries often resulting from or occurring in conjunction with MUCL insufficiency. These conditions include valgus extension overload syndrome, osteochondritis dissecans, olecranon stress fractures, and ulnar nerve pathology.

Traction MRI of the Elbow: Age-Based Effects and Implications

BACKGROUND/OBJECTIVES

We previously reported that traction magnetic resonance imaging (MRI) of the elbow without arthrography increases the width of the radiocapitellar joint (RC) and improves articular cartilage visibility. However, the effects of axial traction on different age groups have not yet been evaluated. We hypothesized that the effect of traction would decrease as the participants' age increased.

METHODS

We enrolled 30 healthy volunteers, ten each in their 20s, 30s, and 40s. The male-to-female ratio in each age group was 1:1. Elbow MRI was performed without traction and with 3, 5, and 7 kg axial traction. We evaluated joint space width (JW), humeral articular cartilage visibility, and intraprocedural pain/discomfort. We measured JW and cartilage visibility at the RC and the lateral and medial thirds of the ulnohumeral joint.

RESULTS

The older age groups exhibited narrower JWs without traction. Axial traction increased the JW and improved the visibility of the RC in all age groups. No significant differences were observed in the ulnohumeral joint's lateral or medial thirds, but pain and discomfort increased with heavier traction weights.

CONCLUSIONS

For participants in their 20s and 30s, axial traction of 3 kg seemed appropriate, while 7 kg traction was considered for those in their 40s.

Variable Return to Play and Sport Performance After Elbow Ulnar Collateral Ligament Reconstruction in Baseball Players: A Systematic Review

PURPOSE

To evaluate return to play (RTP) and return to same level of play (RTSP) rates as well as preoperative and postoperative in-game performance metrics in baseball pitchers who underwent ulnar collateral ligament reconstruction (UCLR). Secondarily, this review sought to assess outcomes based on primary versus revision UCLR as well as level of competition.

METHODS

This review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed/MEDLINE, Embase, Web of Science, and Cochrane Database of Systematic Reviews were queried to identify articles evaluating UCLR in baseball players between January 2002 and October 2022. Data included RTP, RTSP, and performance metrics including earned run average, innings pitched, walks and hits per inning pitched, batting average against, strikeouts per 9 innings, walks per 9 innings, percentage of fastballs thrown, and average fastball velocity. The Methodological Index for Non-randomized Studies criteria were used for quality assessment.

RESULTS

Analysis included 25 articles reporting on 2,100 elbows. After primary UCLR, RTP ranged from 336 to 615 days (57% to 100% achieved) and RTSP ranged from 330 to 513 days (61% to 95%). After revision UCLR, RTP ranged from 381 to 631 days (67% to 98%) and RTSP ranged from 518 to 575 days (42% to 78%). When stratifying primary UCLR outcomes by competitive level, RTP and RTSP ranged respectively from 417 to 615 days (75% to 100%) and 513 days (73% to 87%) for Major League Baseball only, 409 to 615 days (57% to 100%) and 470 to 513 days (61% to 95%) for Major League Baseball plus Minor League Baseball, and 336 to 516 days (73% to 85%) and 330 days (55% to 74%) for college plus high school. Heterogeneity was seen in postoperative sports performance metrics.

CONCLUSIONS

Although more than half of baseball players appear able to RTP after primary and revision UCLR, RTSP rates after revision UCLR were as low as 42% in the literature. Preoperative and postoperative performance metrics varied.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II-IV studies.

Graft choice and techniques used in elbow ulnar collateral ligament reconstruction over the last 20 years: a systematic review and meta-analysis

BACKGROUND

Elbow medial ulnar collateral ligament (mUCL) injuries have become increasingly common, leading to a higher number of mUCL reconstructions (UCLR). Various techniques and graft choices have been reported. The purpose of this study was to evaluate the prevalence of each available graft choice, the surgical techniques most utilized, and the reported complications associated with each surgical method.

METHODS

A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analysesguidelines. We queried PubMed/MEDLINE, Embase, Web of Science, and Cochrane databases to identify all articles that included UCLR between January 2002 and October 2022. We included all studies that referenced UCLR graft choice, surgical technique, and/or ulnar nerve transposition. Studies were evaluated in a narrative fashion to assess demographics and report current trends in utilization and complications of UCLR as they pertain to graft choice and surgical techniques over the past 20 years. Where possible, we stratified based on graft and technique.

RESULTS

Forty-seven articles were included, reporting on 6671 elbows. The cohort was 98% male, had a weighted mean age of 21 years and follow-up of 53 months. There were 6146 UCLRs (92%) performed with an autograft and 152 (2.3%) that utilized an allograft, while 373 (5.6%) were from mixed cohorts of autograft and allograft. Palmaris longus autograft was the most utilized mUCL graft choice (64%). The most utilized surgical configuration was the figure-of-8 (68%). Specifically, the most common techniques were the modified Jobe technique (37%), followed by American Sports Medicine Institute (ASMI) (22%), and the docking (22%) technique. A concomitant ulnar nerve transposition was performed in 44% of all patients, with 1.9% of these patients experiencing persistent ulnar nerve symptoms after ulnar nerve transposition. Of the total cohort, 14% experienced postoperative ulnar neuritis with no prior preoperative ulnar nerve symptoms. Further, meta-analysis revealed a significantly greater revision rate with the use of allografts compared to autograft and mixed cohorts (2.6% vs. 1.8% and 1.9%, P = .003).

CONCLUSIONS

Most surgeons performed UCLR with palmaris autograft utilizing a figure-of-8 graft configuration, specifically with the modified Jobe technique. The overall rate of allograft use was 2.3%, much lower than expected. The revision rate for UCLR with allograft appears to be greater compared to UCLR with autograft, although this may be secondary to limited allograft literature.

Outcomes following arthroscopic posteromedial osteophyte resection and risk of future ulnar collateral ligament reconstruction

BACKGROUND AND HYPOTHESIS

Despite successful return-to-sport (RTS) outcomes after posteromedial osteophyte resection, one possible consequence of osteophyte removal is increased stress on the ulnar collateral ligament (UCL), leading to a UCL injury. It is currently unknown how often overhead athletes who undergo isolated posteromedial osteophyte resection subsequently require UCL reconstruction (UCLR). Therefore, the purpose of this study was to report outcomes following arthroscopic resection of posteromedial osteophytes in overhead athletes and determine whether overhead athletes who underwent arthroscopic posteromedial osteophyte resection for posteromedial impingement went on to require UCL surgery. We hypothesized that there would be a high rate of RTS following osteophyte resection and that players who underwent arthroscopic posteromedial osteophyte resection would have a >10% risk of requiring subsequent UCLR or UCL repair.

MATERIALS AND METHODS

All patients who underwent elbow arthroscopy from 2010-2020 at a single institution were reviewed. Patients were included if they underwent isolated arthroscopic posteromedial osteophyte resection without concomitant UCL surgery, were overhead athletes at the onset of posteromedial impingement symptoms, and had no history of elbow surgery. Primary outcomes included RTS rate, complications, and subsequent shoulder and/or elbow injury and surgery, as well as several patient-reported outcome measures (Kerlan-Jobe Orthopaedic Clinic score, Timmerman-Andrews elbow score, and Conway-Jobe score).

RESULTS

Overall, 36 overhead athletes were evaluated at 5.1 ± 3.4 years postoperatively, including 28 baseball pitchers, 3 baseball catchers, 3 softball players, 1 tennis player, and 1 volleyball player. Of the overhead athletes, 77% were able to RTS; the mean Kerlan-Jobe Orthopaedic Clinic and satisfaction scores were 70 and 75, respectively; and 89% of athletes had either excellent (73%) or good (16%) Conway-Jobe scores at long-term follow-up. Subsequent UCLR was required in 18% of baseball pitchers (n = 5) at a median of 13 months postoperatively. Of the 5 UCLRs, 3 were performed shortly after posteromedial osteophyte resection (6, 7, and 13 months postoperatively) whereas the other 2 were performed at 6.2 and 7.5 years postoperatively.

CONCLUSION

Following arthroscopic posteromedial osteophyte resection, 77% of athletes were able to RTS. Baseball pitchers who undergo arthroscopic resection of posteromedial osteophytes for posteromedial impingement have an 18% risk of subsequent UCLR.

Hypertrophy of the sublime tubercle in elbow ulnar collateral ligament injuries: a case series of baseball pitchers undergoing ulnar collateral ligament reconstruction with short-term follow-up

Background

The ulnar collateral ligament (UCL) of the elbow is subject to repetitive stress in overhead throwing athletes. This can lead to morphologic changes at the bony attachments of the UCL and hypertrophy of the sublime tubercle. The purpose of this case series is to describe the surgical details and clinical outcomes of a series of competitive baseball pitchers with hypertrophic sublime tubercles who underwent UCL reconstruction (UCLR).

Methods

All baseball pitchers who were treated for UCL injuries with significant hypertrophy of the sublime tubercle on preoperative imaging were included in the series. Clinical history, preoperative imaging, intraoperative findings during UCLR, and postoperative outcomes measured with the Conway scale were described.

Results

Ten players (average age of 22.9 years [range 13-39]) were included (average follow-up 20.4 months [range 3-38 months]). Five patients also had symptoms of ulnar nerve compression, with 4 requiring transposition at the time of ULCR and 1 at 3 months postoperatively. Bony hypertrophy of the sublime tubercle was confirmed intraoperatively in all cases and excised before UCLR with the docking technique. Of the 7 patients with at least 12-month follow-up postoperatively, 6 had excellent outcomes, and 1 had a fair outcome.

Conclusion

Although UCLR in the setting of hypertrophic sublime tubercle can be more complex than typical UCLR, excellent outcomes are achievable with preoperative recognition and surgical planning.

Rehabilitation and Return to Sport Criteria Following Ulnar Collateral Ligament Reconstruction: A Systematic Review

BACKGROUND

Ulnar collateral ligament (UCL) reconstruction (UCLR) is a viable treatment option for patients with UCL insufficiency, especially in the overhead throwing athlete. Within the clinical literature, there is still no universally agreed upon optimal rehabilitation protocol and timing for return to sport (RTS) after UCLR.

HYPOTHESIS

There will be significant heterogeneity with respect to RTS criteria after UCLR. Most surgeons will utilize time-based criteria rather than functional or performance-based criteria for RTS after UCLR.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

All level 1 to 4 studies that evaluated UCLR with a minimum 1-year follow-up were eligible for inclusion. Studies lacking explicit RTS criteria, studies that treated UCL injury nonoperatively or by UCL repair, or studies reporting revision UCLR were excluded. Each study was analyzed for methodologic quality, RTS, timeline of RTS, and RTS rate.

RESULTS

Overall, 1346 studies were identified, 33 of which met the inclusion criteria. These included 3480 athletes across 21 different sports. All studies reported RTS rates either as overall rates or via the Conway-Jobe scale. Timelines for RTS ranged from 6.5 to 16 months. Early bracing with progressive range of motion (ROM) (93.9%), strengthening (84.8%), and participation in an interval throwing program (81.8%) were the most common parameters emphasized in these rehabilitation protocols. While all studies included at least 1 of 3 metrics for the RTS value assessment, most commonly postoperative rehabilitation (96.97%) and set timing after surgery (96.97%), no article completely defined RTS criteria after UCLR.

CONCLUSION

Overall, 93.9% of studies report utilizing bracing with progressive ROM, 84.8% reported strengthening, and 81.8% reported participation in an interval throwing program as rehabilitation parameters after UCLR. In addition, 96.97% reported timing after surgery as a criterion for RTS; however, there is a wide variability within the literature on the recommended time from surgery to return to activity. Future research should focus on developing a comprehensive checklist of functional and performance-based criteria for safe RTS after UCLR.

Routine diagnostic arthroscopy with elbow ulnar collateral ligament reconstruction does not reduce the need for future valgus extension overload-related surgeries: a systematic review and meta-analysis

BACKGROUND

Valgus extension overload syndrome (VEOS) most commonly affects overhead athletes and consists of a constellation of conditions involving the medial, posterior, and lateral elbow, with the most widely discussed being ulnar collateral ligament (UCL) injuries. Many athletes with UCL tears also have findings consistent with other VEOS conditions, though these are not consistently symptomatic. Given the high rate of concomitant pathology, many authors have recommended performing arthroscopy at the time of UCL reconstruction (UCLR) to diagnose and address concomitant VEOS pathology; however, it is not known if this practice actually leads to a reduction in subsequent surgeries for VEOS conditions following index UCLR. The purpose of this systematic review and meta-analysis was to determine if performing routine diagnostic arthroscopy (RDA) in patients undergoing UCLR was associated with a lower incidence of future VEOS-related surgery.

METHODS

This study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with the primary outcome of interest being the likelihood of needing future surgery to address VEOS conditions with or without RDA at the time of index UCLR. The proportion and incidence rate of subsequent VEOS-related surgeries following UCLR with and without RDA were compared in mixed effects models.

RESULTS

There were 25 eligible studies from an initial 1335 systematically identified articles, with results for 2118 UCLR cases. Among these, there were a total of 94 reported VEOS-related surgeries. The proportion of subsequent VEOS-related surgeries was lower when UCLR was performed with RDA (0.40%, 95% CI 0.00%-3.51%) than without (1.16%, 95% CI 0.03%-3.25%), but the difference was not significant (P = .584). The incidence rate of VEOS-related surgeries was 0.16 (95% CI 0.00-0.95) per 100 person-years with RDA and 0.14 (95% CI 0.00-0.55) per 100 person-years without RDA (P = .942).

CONCLUSION

RDA preceding UCLR does not significantly reduce the proportion or rate of subsequent surgery for other VEOS conditions. There has been a decrease in RDA utilization with UCLR over time for athletes with torn/incompetent UCLs but otherwise no known symptomatic VEOS conditions, and this trend appears to be justified based on these findings.

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.

Effect of elbow MRI with axial traction on articular cartilage visibility-a feasibility study

OBJECTIVE

Accurate evaluation of the articular cartilage of the elbow using MRI is sometimes challenging because of its anatomical complexity and relatively small size. Moreover, the articular cartilage of the humerus is in close contact with the opposing cartilage surfaces. Magnetic resonance arthrography with traction was reported to resolve this issue; however, less invasive methods are desirable. This study aimed to assess the effect of MRI with axial traction (without arthrography) on joint space widening and cartilage outline visibility of the elbow.

MATERIALS AND METHODS

We enrolled 10 volunteers (female = 1; mean age, 36.7 ± 8.6; range 28-56) and performed MRI with and without axial traction on the elbow. Joint space widths were measured, and the humeral articular cartilage outline visibility was evaluated at the radiocapitellar joint and lateral one-third and medial one-third of the ulnohumeral joints. Measurements were compared using the Wilcoxon signed-rank test. Significance was set at p < 0.05. Volunteers scored pain and discomfort during MRI with traction using the visual analog scale in a questionnaire format.

RESULTS

Traction significantly increased joint space width at the radiocapitellar joint. Humeral articular cartilage outline visibility also significantly improved at the radiocapitellar joint. Pain and discomfort scores during traction MRI were low.

CONCLUSION

MRI of the elbow with traction widens joint space and enables better articular cartilage visibility at the radiocapitellar joint. Anatomical features of the elbow might have affected these results. Therefore, it would be safe and useful for evaluating elbow injuries involving articular cartilage lesions.

Management of Ulnar Collateral Ligament Injuries in Overhead Athletes

Ulnar collateral ligament injuries of the elbow are frequent among overhead athletes. The incidence of ulnar collateral ligament reconstructions (UCLRs) in high-level players has increased dramatically over the past decade, but the optimal technique of UCLR is controversial. Surgeons need to manage the patients’ expectations appropriately when considering the mode of treatment. This article reviews current studies on the management of ulnar collateral ligament injuries, particularly in overhead athletes.

Elbow MR arthrography with traction

OBJECTIVE

To assess the effect of axial traction during MR arthrography (MRA) of the elbow joint on joint space widening, contrast dispersion between opposing cartilage surfaces and cartilage surface visibility.

METHODS

11 patients with elbow MRA with and without axial traction were prospectively studied. Two radiologists independently measured the elbow joint space width and semi-quantitatively graded contrast material dispersion between the opposing cartilage surfaces as well as the articular cartilage surface visibility before and after traction. The detection and visibility of articular cartilage defects were also compared before and after traction. Patients were instructed to report on pain or any other symptoms during elbow traction.

RESULTS

No patient reported discomfort, pain or any other symptoms related to traction on immediate and intermediate-term follow-up. Joint space width increased, more at the radiocapitellar joint space (Δ = 0.63 mm, p = 0.005) than at the ulnotrochlear joint space (Δ = 0.17 mm, p = 0.012), with contrast dispersion into the radiocapitellar joint and cartilage visibility of the radiocapitellar joint space significantly improving after traction (all p < 0.05). All of these parameters also improved at the ulnotrochlear joint, although this did not reach statistical significance. Traction improved the visibility of cartilage defects.

CONCLUSION

This is the first study to evaluate the effect of traction on MRA of the elbow joint. This technique is safe and technically feasible. Traction MRA improves the cartilage surface visibility and cartilage defect visibility.

ADVANCES IN KNOWLEDGE

This technique is safe and technically feasible. Traction MRA improves cartilage surface visibility and cartilage defect visibility.

Impact of Ulnar Collateral Ligament Tear on Posteromedial Elbow Biomechanics

Ulnar collateral ligament insufficiency has been shown to result in changes in contact pressure and contact area in the posteromedial elbow. This study used new digital technology to assess the effect of a complete ulnar collateral ligament tear on ulnohumeral contact area, contact pressure, and valgus laxity throughout the throwing motion. Nine elbow cadaveric specimens were tested at 90° and 30° of elbow flexion to simulate the late cocking/early acceleration and deceleration phases of throwing, respectively. A digital sensor was placed in the posteromedial elbow. Each specimen was tested with valgus torque of 2.5 Nm with the anterior band of the ulnar collateral ligament intact and transected. A camera-based motion analysis system was used to measure valgus inclination of the forearm with the applied torque. At 90° of elbow flexion, mean contact area decreased significantly (107.9 mm(2) intact vs 84.9 mm(2) transected, P=.05) and average maximum contact pressure increased significantly (457.6 kPa intact vs 548.6 kPa transected, P<.001). At 30° of elbow flexion, mean contact area decreased significantly (83.9 mm(2) intact vs 65.8 mm(2) transected, P=.01) and average maximum contact pressure increased nonsignificantly (365.9 kPa intact vs 450.7 kPa transected, P=.08). Valgus laxity increased significantly at elbow flexion of 90° (1.1° intact vs 3.3° transected, P=.01) and 30° (1.0° intact vs 1.7° transected, P=.05). Ulnar collateral ligament insufficiency was associated with significant changes in contact area, contact pressure, and valgus laxity during both relative flexion (late cocking/early acceleration phase) and relative extension (deceleration phase) moments during the throwing motion arc.

Effect of distal ulnar collateral ligament tear pattern on contact forces and valgus stability in the posteromedial compartment of the elbow

BACKGROUND

It is not known whether the pattern of ulnar collateral ligament (UCL) tear affects elbow biomechanics.

HYPOTHESIS

There will be a significant change in elbow biomechanics with 50% proximal but not 50% distal simulated rupture of the UCL.

STUDY DESIGN

Controlled laboratory study.

METHODS

Pressure sensors in the posteromedial elbow joint of 25 male cadaveric elbows (average age, 54.9 years; range, 26-66 years) were used to measure contact area, pressure, and valgus torque at 90° and 30° of elbow flexion. Thirteen specimens were tested with the UCL intact, then with proximal-to-distal detachment of 50%, and then with proximal-to-distal detachment of 100% of the anterior band of the UCL from the ulnar attachment. This method was repeated in the remaining 12 specimens in a distal-to-proximal direction.

RESULTS

With 50% proximal-to-distal detachment, contact area decreased significantly versus intact at 90° (91.3 ± 23.6 vs 112.2 ± 26.0 mm(2); P < .001) and 30° (69.3 ± 14.8 vs 83.1 ± 21.6 mm(2); P < .001) of elbow flexion; the center of pressure (COP) moved significantly proximally versus intact at 90° (3.8 ± 2.5 vs 5.4 ± 2.3 mm; P < .001) and 30° (5.9 ± 2.8 vs 7.4±1.9 mm; P < .001). With 50% distal-to-proximal UCL detachment versus intact, no significant change was observed in contact area, movement of the COP, or valgus laxity at either flexion position. With 100% proximal-to-distal and distal-to-proximal detachment, significant change in contact area, movement of the COP, and valgus laxity versus intact was found at 90° and 30° of elbow flexion (P < .05). No significant difference in contact pressure was observed in any test conditions.

CONCLUSION

Significant change in contact area and proximal movement of the COP with 50% proximal UCL detachment and the lack of significant change with 50% distal UCL detachment suggest that the proximal half of the UCL ulnar footprint has a primary role in maintaining posteromedial elbow biomechanics.

CLINICAL RELEVANCE

The findings suggest that surgical reconstruction should aim to reestablish at least the proximal 50% of the UCL ulnar footprint.