Current trends in surgical treatment of the acromioclavicular joint injuries in 2023: a review of the literature.

Background: This article examines the wide range of surgical reconstruction options available for acromioclavicular (AC) joint injuries. However, the lack of consensus regarding the most suitable surgical techniques is attributed to the high and variable failure rates observed with current approaches. Methods: This article presents a comprehensive overview of the current surgical principles and techniques used by renowned experts in the field of AC shoulder injury management. Results: It emphasizes the significance of addressing horizontal and rotational instability in AC injuries and highlights the impact of impaired scapular biomechanics. Conclusion: By exploring these emerging concepts and strategies, the article aims to lay the foundation for future studies aimed at improving treatment outcomes and patient management.

Performance and Return to Play After Surgery for Thoracic Outlet Syndrome in Professional Baseball Players: A Matched Cohort Analysis.

BACKGROUND: Thoracic outlet syndrome (TOS) remains a rare diagnosis but is being recognized as a cause of upper extremity dysfunction in professional baseball players. PURPOSE/HYPOTHESIS: The purpose was to determine performance and return-to-play (RTP) outcomes in professional baseball players after surgical treatment of TOS. The hypothesis was that there would be a high RTP rate in professional baseball players after TOS surgery with no statistical differences in performance between pitchers who had TOS surgery and matched controls. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All professional baseball players who underwent surgical treatment of TOS between 2010 and 2017 were identified using the Major League Baseball Health and Injury Tracking System database. Demographic and performance data (before and after surgery) for each player were recorded. Performance variables were then compared between players who underwent TOS surgery and matched controls. The matching criteria were no history of previous surgeries on affected arm, age at time of surgery, throwing side, level of play (Major or Minor League Baseball), and years of experience playing professional baseball. RESULTS: Overall, 52 players underwent surgery for TOS, of whom 46 (88%) were pitchers. The type of TOS was neurogenic in 69% and venous in 29%. One player had arterial TOS. After TOS surgery, 79% of players returned to play at the same or higher level (RTSP) by 9.5 months and played ≥3 years after surgery. No differences were found in RTSP rate based on the type of TOS. No statistical difference was found in RTP rates between major and minor league players. Pitchers had a 76% RTSP, which was similar to the natural attrition for control pitchers (P = .874). After TOS surgery, pitchers saw a decline in several performance metrics, but these declines were not different from those of control pitchers, indicating that the decline in performance after TOS surgery was no faster than is seen in healthy professional pitchers as they age. CONCLUSION: The rate of RTSP after surgery for TOS in professional baseball players was 79%. There was no difference in RTP based on the type of TOS. Pitchers who underwent surgery for TOS had no significant differences in pitching performance metrics after surgery compared with matched controls.

Evolution of the throwing shoulder: why apes don't throw well and how that applies to throwing athletes.

BACKGROUND: Humans have unique characteristics making us the only primate that can throw well while most other primates throw predominately underhand with poor speed and accuracy. The purpose of this study is to illuminate the uniquely human characteristics that allow us to throw so well. When treating an injury such as a labral tear or capsule tear, this study hopes the reader can gain a better understanding of the issues that lead to the tear and those that may determine the success of treatment besides the actual repair. METHODS: In addition to a review of scientific and medical literature, information was obtained from interviews and experience with primate veterinarians, anthropologists, archeologists, and professional baseball players. These sources were used to study the connection between evolutionary throwing activities and current sports medicine issues. RESULTS: Arm acceleration requires a functional kinetic chain, rapid motor sequences, and the ability to absorb elastic energy in the shoulder. Successful treatment of the throwing shoulder requires awareness of the shoulder's position in the kinetic chain and correction of defects in the ability to execute the kinetic chain. Some problems in the shoulder could reflect regression to a more primitive anatomy or dyskinesis. Return of performance requires regaining the elasticity in the tissues of the shoulder to temporarily store kinetic energy. For example, tissue remodeling after rotator cuff repair continues for months to years; however, the newly formed tissue lacks the same elasticity of the native tendon. This suggests why throwing performance typically does not return for 7 or more months after repair even though there may be structural integrity at 3-4 months. CONCLUSION: The shoulder has developed uniquely in modern man for the act of throwing. The anatomic deficiencies in primates for throwing provide an illustration of the more subtle changes that a throwing athlete might have that are detrimental to throwing. Nonhuman primates have been unable to demonstrate the kinetic chain sequence for throwing secondary to the lack of neurologic pathways required. Humans are more sophisticated and precise in their movements but lack robusticity in their bone and muscle architecture, seen especially in the human rotator cuff. Successful treatment of a throwing injury requires familiarity with the conditions that cause the injury or affect the rehabilitation process. The return of performance following injury or surgery requires regaining the elasticity in the tissues of the shoulder to temporarily store kinetic energy from the kinetic chain.

Subject-specific computational modeling of acromioclavicular and coracoclavicular ligaments.

BACKGROUND: Disruption of the acromioclavicular joint is a common injury. Despite the different surgical procedures described for treating this injury, complications such as loss of reduction and failure of fixation remain unacceptably high. We developed a computer model of the acromioclavicular joint to better understand the biomechanical contributions of the ligaments that are typically injured. METHODS: Six fresh frozen human cadaveric shoulders were tested on an AMTI VIVO 6-degree of freedom test platform to measure force-displacement in inferior translation, anteroposterior translation, and internal rotation before and after sequentially transecting the coracoclavicular and acromioclavicular ligaments. These data were used to construct computer models of each specimen. Three-dimensional computed tomographic scans were used to generate a rigid-body dynamics model using the AnyBody Modeling System. The scapula and clavicle were connected by the acromioclavicular joint capsule, the conoid ligament, and the trapezoid ligament. Subject-specific ligament properties were calculated by matching computer predictions to experimental force-displacement data. RESULTS: The calculated free lengths of the conoid, trapezoid, and acromioclavicular ligaments were 13.5 (±3.2), 11.8 (±2.4), and 11.0 (±2.7) mm, respectively. The calculated stiffnesses of the conoid, trapezoid, and acromioclavicular ligaments were 34.3 (±6.3), 28.4 (±3.2), and 33.8 (±8.2) N/mm, respectively. Root mean square deviation (RMSD) of predicted force-displacement curves relative to experimental force-displacement curves (during inferior and anteroposterior translation) was less than 1 mm. For validation of subject-specific models, after ligament properties were calculated, the RMSD of the predicted torque over 15° of internal rotation was 12% of maximum rotational torque (average for 6 specimens). DISCUSSION AND CONCLUSION: Acromioclavicular disruption results in multidirectional instability, which requires careful consideration of the individual contributions of the injured ligaments. In addition, variations in patient anatomy can significantly affect the biomechanical stability of the reconstruction. Subject-specific models can enhance our understanding of the individual and collective biomechanical contributions of the injured soft tissues to the multiaxial stability of the acromioclavicular joint. These models may also be useful for analyzing and assessing biomechanical stability after various types of surgical reconstruction.

Combination of Surgical Techniques Restores Multidirectional Biomechanical Stability of Acromioclavicular Joint.

PURPOSE: To measure the multiaxial stability of the acromioclavicular joint before and after transection of the acromioclavicular capsule and coracoclavicular ligaments and after sequential repair of acromioclavicular and coracoclavicular ligaments. METHODS: Biomechanical testing was performed on fresh-frozen human cadaveric shoulders (N = 6). Translational and rotational stability in the vertical and horizontal planes was measured in intact specimens, after transecting the acromioclavicular and coracoclavicular ligaments, and after sequentially performing the following procedures: single-bundle coracoclavicular repair (CCR), modified Weaver-Dunn procedure (WD), and acromioclavicular stabilization (ACS). RESULTS: Resecting the acromioclavicular and coracoclavicular significantly reduced translational stiffness in the inferior and anteroposterior directions, as well as rotational stiffness about the vertical and anteroposterior axes. All 3 surgical procedures increased inferior translational stiffness relative to the intact condition (Intact: 38 ± 9 N/mm, CCR: 54 ± 23 N/mm (P = .03), CCR+WD 52 ± 20 N/mm (P = .07), CCR ± WD+ACS 50 ± 21 N/mm (P = .17)). However, the combination of CCR, modified WD, and ACS resulted in the greatest increase in stiffness in internal rotation (Intact: 12.5 ± 7.4 cNm/deg, CCR: 1.2 ± 1.1 cNm/deg, CCR+WD 7.2 ± 3.0 N∗m/deg [P = .023], CCR+WD+ACS 11.6 ± 4.9 cNm/deg [P = .055]). CONCLUSIONS: The cumulative stability of CCR, WD reconstruction, and ACS appears to be additive. Our findings provide a biomechanical justification for combining all three techniques. Biomechanical studies assessing the performance of various acromioclavicular repairs and reconstructions should therefore incorporate multiaxial testing in their protocols. CLINICAL RELEVANCE: Multiple points of fixation that provide multidirectional stability have the potential to improve clinical outcomes and reduce failure rates of acromioclavicular joint repair or stabilization.

Three-Dimensional Zero Echo Time Magnetic Resonance Imaging Versus 3-Dimensional Computed Tomography for Glenoid Bone Assessment.

PURPOSE: To evaluate the 3-dimensional (3D) zero echo time (ZTE) magnetic resonance imaging (MRI) technique and compare it with 3D computed tomography (CT) for the assessment of the glenoid bone. METHODS: ZTE MRI using multiple resolutions and multislice CT were performed in 6 shoulder specimens before and after creation of glenoid defects and in 10 glenohumeral instability patients. Two musculoskeletal radiologists independently generated 3D volume-rendered images of the glenoid en face. Post-processing times and glenoid widths were measured. Inter-modality and inter-rater agreement was assessed. RESULTS: Intraclass correlation coefficients (ICCs) for inter-modality assessment showed almost perfect agreement for both readers, ranging from 0.949 to 0.991 for the ex vivo study and from 0.955 to 0.987 for the in vivo patients. Excellent interobserver agreement was found for both the ex vivo (ICCs ≥ 0.98) and in vivo (ICCs ≥ 0.92) studies. For the ex vivo study, Bland-Altman analyses for CT versus MRI showed a mean difference of 0.6 to 1 mm at 1.0-mm3 MRI resolution, 0.3 to 0.6 mm at 0.8-mm3 MRI resolution, and 0.3 to 0.6 mm at 0.6-mm3 MRI resolution for both readers. For the in vivo study, Bland-Altman analyses for CT versus MRI showed a mean difference of 0.6 to 0.8 mm at 1.0-mm3 MRI resolution, 0.5 to 0.6 mm at 0.8-mm3 MRI resolution, and 0.4 to 0.8 mm at 0.7-mm3 MRI resolution for both readers. Mean post-processing times to generate 3D images of the glenoid ranged from 32 to 46 seconds for CT and from 33 to 64 seconds for ZTE MRI. CONCLUSIONS: Three-dimensional ZTE MRI can potentially be considered as a technique to determine glenoid width and can be readily incorporated into the clinical workflow. LEVEL OF EVIDENCE: Level II, development of diagnostic criteria (consecutive patients with consistently applied reference standard and blinding).

Three-dimensional Volumetric Filling Ratio Predicts Stress Shielding in Short-stem Anatomic Total Shoulder Arthroplasty.

INTRODUCTION: Three-dimensional (3-D) CT volumetric filling ratio (VFR) is a better predictor of proximal humerus stress shielding after short-stem anatomic total shoulder arthroplasty (aTSA) than using plain radiographs. METHODS: Forty-four patients with short-stem aTSAs, preoperative CT scans, and a minimum 3-year radiographic follow-up were included. Patients were divided into group A (stress shielding) and group B (no stress shielding) based on the radiographic analysis. Standard implant filling ratios were measured on plain radiographs. The 3-D VFR of the metaphyseal and diaphyseal segments of the aTSA stem was measured using MIMICS (Materialise). The area under a receiver operator characteristic curve was used to determine the predictive strength of the 3-D VFR method. RESULTS: The average age and radiographic follow-up was 69 years and 44 months. Group A had 19 patients and statistically higher filling ratios using 3-D VFR method than group B, whereas no notable differences were found between the groups using standard techniques. The 3-D VFR had an area under a receiver operator characteristic curve of 92%, which supports it as a good predictor of stress shielding. CONCLUSIONS: These methods enable early identification of patients at risk for stress shielding and can also be valuable in improving humeral stem designs. LEVEL OF EVIDENCE: Level III. Case-control study.

Sagittal orientation of coracoclavicular ligament reconstruction affects the stability of surgical repair.

BACKGROUND: The variation in the anatomic relationship between the coracoid and the clavicle affects the biomechanical stability of coracoclavicular ligament reconstruction (CCLR). METHODS: Three-dimensional computed tomography reconstruction of 85 patients was analyzed. Anatomic landmarks were used to derive the coracoclavicular sagittal reconstruction angle (sRA). The lateral concave angle, which indicated the shape of the distal clavicle, and the offsets between the clavicle and coracoid were also measured. To investigate the biomechanical effects of the sRA on CCLR, 7 computed tomography scans with different sRAs were 3D printed. Two reconstructions, a single trans-coracoclavicular tunnel and a looped reconstruction technique, were performed sequentially. Models were cyclically loaded at 70 N in the anterior, posterior, and superior directions. RESULTS: The mean sRA was 68° ± 9.3° (range, 47°-85°). The superoinferior offset between the clavicle and the coracoid and the lateral concave angle positively correlated with the sRA (r = 0.359 and 0.837, respectively; P ≤ .001), whereas the anteroposterior offset had a negative correlation (r = -0.925; P < .001). The sRA had a negative correlation with the anterior displacement of the clavicle (rho = -0.96; P < .001) and a positive correlation with the posterior displacement for both surgical techniques (rho = 1.0; P < .001). CONCLUSION: The anatomic orientation of the native coracoclavicular ligaments is highly variable in the sagittal plane. Low sagittal angles can reduce anterior stability, whereas high sagittal angles can reduce posterior stability of CCLR.

Vertical and Rotational Stiffness of Coracoclavicular Ligament Reconstruction: A Biomechanical Study of 3 Different Techniques.

PURPOSE: To compare the biomechanical stability of 3 different coracoclavicular reconstruction techniques under rotational and vertical loading using a cadaveric model. METHODS: In total, 12 cadaveric shoulders were used for testing. The native state was first tested then followed by 3 different reconstruction configurations using suture tapes and cortical buttons: coracoid loop (CL), single-bundle (SB), and double-bundle (DB). Superior displacement was measured by cycling an inferiorly directed force of 70 N to the scapula. The rotational stiffness of the scapula was determined by cycling the scapula in rotational displacement control between 15° of internal and external rotation. The rotational stiffness of the clavicle was determined by rotating the clavicle around its long axis 20° anteriorly and 30° posteriorly in rotational displacement control. All measurements were captured over 10 cycles at a rate of 200 Hz. RESULTS: Both the CL and SB techniques demonstrated significantly less internal scapular rotation stiffness. (intact: 19.70 ± 9.07 cNm/deg, CL: 3.70 ± 2.63 cNm/deg, SB:4.30 ± 2.66 cNm/deg, P <.001) External scapular rotation stiffness was significantly decreased in all techniques (intact: 17.70 ± 4.43 cNm/deg, CL: 3.30 ± 1.37 cNm/deg, SB: 4.50 ± 1.56 cNm/deg, DB: 4.67 ± 1.99 cNm/deg, P < .001). The CL and SB reconstructions were significantly less stiff with regards to posterior rotation of the clavicle (intact: 5.60 ± 1.80 cNm/deg, CL: 2.90 ± 1.10 cNm/deg, SB: 1.40 ± 0.65 cNm/deg, P < .001). Anterior rotation stiffness of the clavicle was significantly lower in all of the reconstructions (intact: 6.95 ± 1.90 cNm/deg, CL: 3.08 ± 0.84 cNm/deg, SB: 3.64 ± 0.93 cNm/deg, DB: 4.48 ± 1.21 cNm/deg, P < .001). CONCLUSIONS: None of the described techniques provided equivalent rotational stability in all planes compared with the native state. DB reconstruction presented stiffness characteristics closest to the native state under cyclic loading during internal scapular and posterior clavicular rotation. CLINICAL RELEVANCE: Additional procedures such as tendon grafting or acromioclavicular ligament reconstruction may be required to control rotational stability.

Professional Advancement and Performance of Amateur Baseball Players Selected in the Major League Baseball Draft With Previous Anterior Cruciate Ligament Reconstruction.

BACKGROUND: The effect that an anterior cruciate ligament injury requiring reconstructive surgery has on the professional advancement and performance of amateur baseball players selected in the Major League Baseball draft is not known. Return to sports after anterior cruciate ligament reconstruction (ACLR) in professional athletes has been shown to be high, but mixed results with regard to performance and return to preinjury level have been demonstrated in other sports. PURPOSE: To (1) investigate the highest level of professional advancement among Major League Baseball draftees with a history of ACLR before entering the draft, (2) examine how much time these players spent on the disabled list (DL) and determine if it was related to the knee, and (3) compare the batting and pitching performance of these players against healthy matched controls. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Predraft medical records of all players selected in the Major League Baseball draft from 2004 to 2008 were reviewed. Players with a documented anterior cruciate ligament injury treated with ACLR before the draft were included. For each study player, 3 controls were identified. Data were accumulated from the time when players were drafted through the 2015 season. Outcome variables included highest professional level of advancement, DL time, and batting and pitching performance. RESULTS: Forty draftees with a history of ACLR (22 pitchers, 18 position players) were identified and matched to 120 controls (66 pitchers, 54 position players). The difference in the highest level of professional advancement between the groups was not statistically significant (P = .488). The mean total number of times and the mean total number of days on the DL were similar between the groups (1.83 vs 1.47, P = .297; 121.54 vs 109.62, P = .955); however, the mean number of times on the DL because of a knee injury was significantly different (0.28 vs 0.11, P = .004), as was the mean number of days on the DL because of a knee injury (17.36 vs 7.72, P = .009). Among pitchers, there were no differences in performance. Similarly, there were no differences among position players in batting performance. CONCLUSION: There was no difference between draftees with a history of ACLR and their controls in terms of advancement from the minor to the major leagues. Additionally, pitching and batting performance were similar. Although the 2 groups spent similar time on the DL, the ACLR group spent more time on the DL because of a knee injury than the control group.

Nonoperative Treatment of Elbow Ulnar Collateral Ligament Injuries With and Without Platelet-Rich Plasma in Professional Baseball Players: A Comparative and Matched Cohort Analysis.

BACKGROUND: Recent studies evaluating nonoperative treatment of elbow ulnar collateral ligament (UCL) injuries augmented with platelet-rich plasma (PRP) have shown promising results. To date, no comparative studies have been performed on professional baseball players who have undergone nonoperative treatment with or without PRP injections for UCL injuries. HYPOTHESIS: Players who received PRP injections would have better outcomes than those who did not receive PRP. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The Major League Baseball (MLB) Health and Injury Tracking System identified 544 professional baseball players who were treated nonoperatively for elbow UCL injuries between 2011 and 2015. Of these, 133 received PRP injections (PRP group) before starting their nonoperative treatment program, and 411 did not (no-PRP group). Player outcomes and a Kaplan-Meier survival analysis were compared between groups. In addition, to reduce selection bias, a 1:1 matched comparison of the PRP group versus the no-PRP group was performed. Players were matched by age, position, throwing side, and league status: major (MLB) and minor (Minor League Baseball [MiLB]). A single radiologist with extensive experience in magnetic resonance imaging (MRI) interpretation of elbow injuries in elite athletes analyzed 243 MRI scans for which images were accessible for tear location and grade interpretation. RESULTS: Nonoperative treatment of UCL injuries resulted in an overall 54% rate of return to play (RTP). Players who received PRP had a significantly longer delay in return to throwing (P < .001) and RTP (P = .012). The matched cohort analysis showed that MLB and MiLB pitchers in the no-PRP group had a significantly faster return to throwing (P < .05) and the MiLB pitchers in the no-PRP group had a significantly faster RTP (P = .045). The survival analysis did not reveal significant differences between groups over time. The use of PRP, MRI grade, and tear location were not statistically significant predictors for RTP or progression to surgery. CONCLUSION: In this retrospective matched comparison of MLB and MiLB pitchers and position players treated nonoperatively for a UCL tear, PRP did not improve RTP outcomes or ligament survivorship, although there was variability with respect to PRP preparations, injection protocols, time from injury to injection, and rehabilitation programs. MRI grade and tear location also did not significantly affect RTP outcomes or progression to surgery.

Scapulothoracic rhythm affects glenohumeral joint force.

HYPOTHESIS: Musculoskeletal computer models provide valuable insights into shoulder biomechanics. The shoulder is a complex joint composed of glenohumeral, scapulothoracic, acromioclavicular, and sternoclavicular articulations, whose function is largely dependent on the many muscles spanning these joints. However, the range of patient-to-patient variability in shoulder function is largely unknown. We therefore assessed the sensitivity of glenohumeral forces to population-based model input parameters that were likely to influence shoulder function. METHODS: We constructed musculoskeletal models of the shoulder in the AnyBody Modeling System (AnyBody Technology, Aalborg, Denmark). We used inverse dynamics and static optimization to solve for glenohumeral joint forces during a simulated shoulder elevation. We generated 1000 AnyBody models by uniformly distributing the following input parameters: subject height, scapulohumeral rhythm, humeral head radius, and acromiohumeral interval. RESULTS: Increasing body height increased glenohumeral joint forces. Increasing the ratio of scapulothoracic to glenohumeral elevation also increased forces. Increasing humeral head radius and acromiohumeral interval decreased forces. The relative sensitivity of glenohumeral joint forces to input parameters was dependent on the angle of shoulder elevation. We developed an efficient method of generating and simulating musculoskeletal models representing a large population of shoulder arthroplasty patients. We found that scapulohumeral rhythm had a significant influence on glenohumeral joint force. CONCLUSIONS: This finding underscores the importance of more accurately measuring and simulating scapulothoracic motion rather than using fixed ratios or average scapulothoracic motion. This modeling approach can be used to generate virtual populations for conducting efficient simulations and generating statistical conclusions.

A Review of Commercially Available Point-of-Care Devices to Concentrate Bone Marrow for the Treatment of Osteoarthritis and Focal Cartilage Lesions.

OBJECTIVE: Mesenchymal stem cells (MSCs) are a promising cell-based therapy treatment option for several orthopedic indications. Because culture expansion of MSC is time and cost intensive, a bedside concentration of bone marrow (BM) aspirate is used as an alternative. Many commercial systems are available but the available literature and knowledge regarding these systems is limited. We compared different point-of-care devices that concentrate BM (BMC) by focusing on technical features and quality parameters to help surgeons make informed decisions while selecting the appropriate device. METHODS: We compared published data on the BMC devices of Arteriocyte, Arthrex, Celling Biosciences, EmCyte, Exactech, ISTO Tech, Harvest Tech/Terumo BCT, and Zimmer/BIOMET regarding technical features (centrifugation speed/time, input/output volume, kit components, type of aspiration syringes, filter usage) and quality parameters of their final BMC product (hematocrit, concentration of platelets and total nucleated cells, concentration of MSC and connective tissue progenitor cells). RESULTS: The systems differ significantly in their technical features and centrifugation parameters. Only the fully automated systems use universal kits, which allow processing different volumes of BM. Only the Arthrex system allows selection of final hematocrit. There was no standardized reporting method to describe biologic potency. CONCLUSIONS: Based on the data obtained in this review, recommending a single device is not possible because the reported data could not be compared between devices. A standardized reporting method is needed for valid comparisons. Furthermore, clinical outcomes are required to establish the true efficacy of these systems. We are conducting additional studies for more careful comparison among the devices.

Professional advancement, performance, and injury characteristics of baseball players entering the Major League Baseball draft after treatment for shoulder injuries.

BACKGROUND: How shoulder injuries treated before the Major League Baseball (MLB) draft affect the player's performance over their career is unclear. The purpose of this study was to determine whether prior shoulder injuries were associated with a difference in the level of performance and advancement of MLB draftees. METHODS: Before entering the draft, 119 professional baseball players from 2004 to 2010 were treated for a shoulder injury (73% treated surgically) as an amateur. A 3:1 matched case-control was performed to players without prior shoulder injuries by age, position, round selected, and signing bonus. Follow-up data were collected in 2016, and professional advancement, disabled list time, and in-game performance statistics for pitchers were analyzed and compared. RESULTS: Players with a prior shoulder injury had a statistically higher chance to be assigned to the disabled list then controls (P = .03), but there was no difference in disabled list time or professional advancement. Pitchers with a prior shoulder injury pitched a statistically lower number of innings per game than controls (P = .04). All other in-game performance statistics were not statistically different. The type of treatment did not have any effect on future performance or advancement. CONCLUSIONS: Professional baseball players treated for prior shoulder injuries at the amateur level were more likely to sustain future disability than their matched controls, but it did not affect professional advancement.

Feasibility of using an inversion-recovery ultrashort echo time (UTE) sequence for quantification of glenoid bone loss.

OBJECTIVE: To utilize the 3D inversion recovery prepared ultrashort echo time with cones readout (IR-UTE-Cones) MRI technique for direct imaging of lamellar bone with comparison to the gold standard of computed tomography (CT). MATERIALS AND METHODS: CT and MRI was performed on 11 shoulder specimens and three patients. Five specimens had imaging performed before and after glenoid fracture (osteotomy). 2D and 3D volume-rendered CT images were reconstructed and conventional T1-weighted and 3D IR-UTE-Cones MRI techniques were performed. Glenoid widths and defects were independently measured by two readers using the circle method. Measurements were compared with those made from 3D CT datasets. Paired-sample Student's t tests and intraclass correlation coefficients were performed. In addition, 2D CT and 3D IR-UTE-Cones MRI datasets were linearly registered, digitally overlaid, and compared in consensus by these two readers. RESULTS: Compared with the reference standard (3D CT), glenoid bone diameter measurements made on 2D CT and 3D IR-UTE-Cones were not significantly different for either reader, whereas T1-weighted images underestimated the diameter (mean difference of 0.18 cm, p = 0.003 and 0.16 cm, p = 0.022 for readers 1 and 2, respectively). However, mean margin of error for measuring glenoid bone loss was small for all modalities (range, 1.46-3.92%). All measured ICCs were near perfect. Digitally registered 2D CT and 3D IR-UTE-Cones MRI datasets yielded essentially perfect congruity between the two modalities. CONCLUSIONS: The 3D IR-UTE-Cones MRI technique selectively visualizes lamellar bone, produces similar contrast to 2D CT imaging, and compares favorably to measurements made using 2D and 3D CT.

Performance and Injury Characteristics of Pitchers Entering the Major League Baseball Draft After Ulnar Collateral Ligament Reconstruction.

BACKGROUND: Ulnar collateral ligament (UCL) reconstruction (UCLR) has been studied and shown to be a successful procedure for returning overhead athletes to sport. Many studies of Major League Baseball (MLB) players have shown high levels of return to play with successful statistical performance. No study has followed professional advancement of drafted pitchers who underwent UCLR as amateurs when compared with drafted pitchers who did not undergo the procedure before selection in the MLB draft. HYPOTHESIS: There would be no difference in professional advancement, statistical performance, or injury rate between the UCLR and control groups. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Thirty-eight pitchers with a UCLR as an amateur and 114 controls were identified in the MLB draft between 2006 and 2010. Highest level of professional baseball achieved was collected from all players, as well as statistical performance metrics including velocity, wins, earned run average (ERA), and walks and hits per inning pitched (WHIP). Additional data on future injuries were analyzed for days on the disabled list (DL), risk of being placed on the DL, and DL assignment for elbow injury. RESULTS: Thirteen of 38 UCLR pitchers reached the major league level (34.2%) compared with 29 of 114 (25.4%) control pitchers, which was not statically significant (P = .295). The UCLR and control groups were similar for average velocity, peak velocity, innings pitched, games, games started, innings per game, ERA, WHIP, wins, losses, saves, batters faced, and innings pitched per year, as well as hits, runs, home runs allowed, strikeouts, batters walked, and batters struck per inning. The UCLR group had a significantly increased rate of DL assignment when compared with controls (86.8% vs 64.0%; P = .008); however, days on DL (152.8 vs 135.6; P = .723) and DL assignment for elbow injury (45.5% vs 43.8%; P = .877) were similar. CONCLUSION: There was no difference in the rate of professional advancement among pitchers drafted by the MLB who had undergone UCLR as amateurs compared with controls. Both groups had similar statistical performance. Pitchers in the UCLR group had an increased risk of DL assignment but no increase in the number of days on DL or risk of DL placement for elbow injury.

Posterior augmented glenoid implants require less bone removal and generate lower stresses: a finite element analysis.

HYPOTHESIS: Glenoid retroversion can be corrected with standard glenoid implants after anterior-side asymmetric reaming or by using posterior augmented glenoid implants with built-in corrections. The purpose of this study was to compare 2 augmented glenoid designs with a standard glenoid design, measure the amount of bone removed, and compute the stresses generated in the cement and bone. METHODS: Finite element models of 3 arthritic scapulae with varying severities of posterior glenoid wear were each implanted with 4 different implant configurations: standard glenoid implant in neutral alignment with asymmetric reaming, standard glenoid implant in retroversion, glenoid implant augmented with a posterior wedge in neutral alignment, and glenoid implant augmented with a posterior step in neutral alignment. The volume of cortical and cancellous bone removed and the percentage of implant back surface supported by cortical bone were measured. Stresses and strains in the implant, cement, and glenoid bone were computed. RESULTS: Asymmetric reaming for the standard implant in neutral version required the most bone removal, resulted in the lowest percentage of back surface supported by cortical bone, and generated strain levels that risked damage to the most bone volume. The wedged implant removed less bone, had a significantly greater percentage of the back surface supported by cortical bone, and generated strain levels that risked damage to significantly less bone volume. CONCLUSIONS: The wedged glenoid implants appear to have various advantages over the standard implant for the correction of retroversion. LEVEL OF EVIDENCE: Basic Science Study; Computer Modeling.

Outcomes of anatomic shoulder arthroplasty in primary osteoarthritis in type B glenoids.

BACKGROUND: Primary glenohumeral osteoarthritis with posterior wear of the glenoid and posterior subluxation of the humerus (Walch type B) presents a challenge to the treating surgeon. Our hypothesis was that glenoids with biconcavity (B2) would be associated with worse outcomes (functional scores and complications) than B1 glenoids. MATERIALS AND METHODS: We retrospectively analyzed prospectively collected data on 112 anatomic total shoulder arthroplasties (104 patients) with B glenoids. Preoperative computed tomography identified 64 B1 glenoids and 48 B2 glenoids (50 and 37 available for follow-up). RESULTS: A significant difference between B1 and B2 glenoids was noted in average retroversion (11° vs. 16°; P < .001) and average posterior humeral subluxation (65% vs. 75%; P < .001). No significant difference was seen in mean age (69.5 vs. 69.2 years) or body mass index (28.5 vs. 27.4) at time of surgery. At average follow-up of 60 months (range, 23-120 months), glenoid component radiolucencies (51.6%, B1; 47.9%, B2), range of motion, preoperative and postoperative scores of the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire, and patient satisfaction were not significantly different between the 2 groups. Four revisions (4.6%) were documented for acute postoperative infection (2.3%), subscapularis failure (1.1%), and glenoid loosening (1.1%). CONCLUSIONS: Although biconcave glenoids commonly have more severe retroversion and posterior subluxation of the humerus, we were unable to find a clinical or radiographic difference in outcome of patients with B1 or B2 glenoids treated with anatomic total shoulder arthroplasty at intermediate-term follow-up. Continued clinical and radiographic follow-up of these cohorts will be necessary to assess any future divergence in outcome.

Long head of the biceps brachii tendon: unenhanced MRI versus direct MR arthrography.

OBJECTIVE: We sought to determine the diagnostic accuracy of unenhanced MRI and direct MR arthrography (MRA) for evaluation of the intra-articular long head of the biceps brachii tendon (LHBT) using arthroscopy as the gold standard. MATERIALS AND METHODS: A retrospective review of patients who underwent shoulder MRI (n = 132) and MRA (n = 67) within 12 months prior to arthroscopy was performed. MR images were independently reviewed by two blinded musculoskeletal radiologists. Routinely recorded arthroscopic photos/videos were reviewed by an orthopedic surgeon. The LHBT was graded as normal, tendinosis, partial thickness tear less or greater than 50%, and complete tear. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for tendinosis and tear detection were calculated. RESULTS: MRI correctly diagnosed fewer normal LHBTs compared to MRA (39-54% versus 74-84%, respectively; p < 0.005). MRI and MRA did not differ significantly in the diagnosis of tendinosis (18-36% and 15-38%, respectively; p > 0.05) and tears (75-83% and 64-73%, respectively; p > 0.05). For tendinosis, MRI versus MRA showed 18-36% and 15-38% sensitivity, 69-79% and 83-91% specificity, 22-28% and 18-50% PPV, 74-76% and 80-86% NPV, and 61-64% and 70-81% accuracy; respectively. For tears, MRI versus MRA showed 75-83% and 64-73% sensitivity, 73-75% and 82-91% specificity, 66-69% and 41-62% PPV, 82-87% and 92-94% NPV, and 74-78% and 79-88% accuracy; respectively. CONCLUSIONS: No significant difference was found between unenhanced MRI and direct MRA for the detection of tendinosis and tears of LHBTs.

Posterior augmented glenoid designs preserve more bone in biconcave glenoids.

BACKGROUND AND HYPOTHESIS: Total shoulder arthroplasty is recommended treatment for severe osteoarthritis of the glenohumeral joint, which often results in excessive posterior wear. Two recent glenoid components with posterior augments have been designed to correct excessive posterior wear and retroversion. Our primary hypothesis was that posterior augmented glenoid designs require less bone removal than a standard glenoid design. METHODS: Ten arthritic scapulae classified as Walch B2 glenoids were virtually implanted with standard, stepped, and wedged components. The volume of surgical bone removal, the maximum reaming depth, and the portion of the implant surface in contact with cancellous vs. cortical bone were calculated for each implant. RESULTS: The neoglenoid made up an average of 65% ± 12% of the glenoid width. Mean surgical bone volume removed was least for the wedged (2857 ± 1618 mm(3)) compared with the stepped (4307 ± 1485 mm(3); P < .001) and standard (5385 ± 2348 mm(3); P < .001) designs. Maximum bone depth removed for the wedged (4.2 ± 2.0 mm) was less than for the stepped (7.6 ± 1.2 mm; P < .001) and standard (9.9 ± 3.2 mm; P < .001). The mean percentage of the implant's back surface supported by cancellous bone was 18.2% for the standard, 8.8% for the stepped (P = .02), and 4.3% for the wedged (P = .01). DISCUSSION: Both augmented components corrected glenoid version to neutral and required less bone removal, required less reaming depth, and were supported by more cortical bone than in the standard implant. The least amount of bone removed was with the wedged design.