Camp, Christopher L.

Background: Since healing of anterior cruciate ligament (ACL) grafts occurs by formation of a fibrovascular scar-tissue interface rather than by reformation of the native fibrocartilage transition zone, the purpose of our study was to examine expression of various signaling molecules and transcription factors that are known to be involved in embryologic insertion-site development following ACL reconstruction. We also aimed to characterize a murine model of ACL reconstruction to allow future study of the molecular mechanisms of healing. Methods: Seventy-nine mice underwent reconstruction of the ACL with autograft. Healing was assessed using histology in 12 mice and quantitative real-time polymerase chain reaction (qRT-PCR) gene-expression analysis in 3 mice at 1 week postoperatively (Group-1 mice) and by biomechanical analysis in 7, histological analysis in 7, immunohistochemical analysis in 5, microcomputed tomography analysis in 5, and qRT-PCR analyses in 8 at 2 weeks (Group-2 mice) and 4 weeks (Group-3 mice) postoperatively. Fifteen additional mice did not undergo surgery and were used for biomechanical (7 mice), qRT-PCR (3 mice), and immunohistochemical (5 mice) analyses to obtain baseline data for the native ACL. Results: Histological analysis demonstrated healing by formation of fibrovascular tissue at the tendon-bone interface. Immunohistochemical analysis showed a positive expression of proteins in the Indian hedgehog, Wnt, and parathyroid hormone-related protein (PTHrP) pathways. There was minimal Sox-9 expression. Gene-expression analysis showed an initial increase in markers of tissue repair and turnover, followed by a subsequent decline. Mean failure force and stiffness of the native ACL were 5.60 N and 3.44 N/mm, respectively. Mean failure force and stiffness were 1.29 N and 2.28 N/mm, respectively, in Group 2 and were 1.79 N and 2.59 N/mm, respectively, in Group 3, with 12 of 14 failures in these study groups occurring by tunnel pull-out. Conclusions: The spatial and temporal pattern of expression of signaling molecules that direct embryologic insertion-site formation was not adequate to restore the structure and composition of the native insertion site. Clinical Relevance: Development of a murine model to study ACL reconstruction will allow the use of transgenic animals to investigate the cellular, molecular, and biomechanical aspects of tendon-to-bone healing following ACL reconstruction, ultimately suggesting methods to improve healing in patients.

Objectives: Diagnosis of and treatment for posterior shoulder instability (PSI) has improved with advances in surgical technique and radiographic imaging. It is unknown if PSI, or surgical measures to correct PSI, affect the progression of osteoarthritis in the glenohumeral joint. The purpose of this study is to evaluate the effect of posterior capsulolabral reconstruction (PCLR) and demographic risk factors on the rate of radiographic progression of osteoarthritis in shoulders with PSI. Methods: The study population included 115 patients (14 females, 101 males) diagnosed with PSI between January 1994 and July 2012 with an average follow up of 12.5years (range 5-23). Medical records were reviewed to evaluate patient demographics, surgical intervention, and radiographic progression of osteoarthritis. Kaplan Meier survival was used to estimate survival and Cox models were used to examine associations with osteoarthritis progression. Results: Overall, 16/115 (14%) patients had radiographic progression of glenohumeral arthritis with 5-year survival at 88.3% (95% CI 79.7%-97.3%). Age ≥30 at the time of instability was associated with arthritis progression (p<0.05). The number of previous dislocations, sport, and gender each did not affect progression (p>0.05). PCLR with at least one anchor along the posterior glenoid rim was performed in 56/115 (48%) of patients. There was no difference in the rate of radiographic arthritic progression in those who underwent PCLR and those who did not (7/56, 13% vs 10/59, 17%, p>0.05). One male patient who underwent PCLR progressed to end-stage arthritis, necessitating a shoulder arthroplasty at age 53. Conclusion: Radiographic progression of glenohumeral arthritis occurred 14% of patients with PSI. Age ≥30 at the time of initial instability was associated with radiographic progression of glenohumeral arthritis.

Objectives: Among patients treated non-operatively for 1 year following a diagnosis of posterior shoulder instability (PSI), little is known about the the incidence of surgery between 1-13 years after injury. The purpose of this study is to define the frequency and evaluate the factors predictive for late surgical intervention of symptomatic PSI. Methods: This study included a population-based cohort of 115 patients (14 females, 101 males) diagnosed with PSI between January 1994 and July 2012 with a minimum 5-years follow-up (mean:13.9 years; range: 5-23 years). Landmark survival analysis was performed to evaluate incidence of surgery after 1 year. Survival was estimated using Kaplan Meier method and predictors of late surgical intervention were analyzed using Cox proportional hazards regression. Results: A total of 61/115 (53%) patients were treated non-operatively for 1 year following diagnosis of PSI. Of these, 24/61 (39%) converted to surgery for symptomatic PSI. The overall survival free of surgery at 1 and 5 years was 53.0% (95% CI 434.7-63.0) and 37.1% (95% CI 29.1-47.1), respectively. BMI >35 (p=0.04, HR 3.3) was predictive for late conversion to surgery. Age, gender, occupation, or history of glenohumeral dislocation were not significant. Assessing surgery as a time dependent covariate, a patient undergoing surgery was at an increased risk for radiographic progression of osteoarthritis (p=0.02, HR=4.0, 95% CI 1.2-13.2). Conclusion: Conservative management was performed for at least one year in over half of patients diagnosed with PSI. However, long-term follow-up demonstrates that nearly 40% of these patients eventually require surgery. Increased BMI was predictive for late failure of while age, gender, history of dislocation and occupation did not show an effect. Patients who underwent surgery were at an increased risk of radiographic progression of arthritis.

Objectives: Professional baseball pitchers are at high risk for tears of the ulnar collateral ligament (UCL) of the elbow, often requiring subsequent surgical reconstruction. Despite acceptable published return to play outcomes, multiple techniques and graft types have been described. There is a paucity of clinical data in the current literature comparing UCL reconstruction surgical technique and graft type. Even less is known about the risks for subsequent injury, surgery, or revision UCL reconstruction. Accordingly, this study compares UCL reconstruction outcomes based on tunnel configuration and graft type. Methods: Following approval from our institutional review board and Major League Baseball (MLB), 566 professional baseball pitchers who underwent UCL reconstruction between 2010 and 2014 were identified and included. The following patient demographics were analyzed: age, pitching role (starter vs. reliever), level of play (MLB vs. Minor League Baseball [MiLB]), and throwing side dominance. Surgical factors analyzed included reconstruction technique (Docking vs. Modified Jobe), graft type (palmaris longus autograft vs. gracilis autograft), and concomitant procedures. Primary outcome measures consisted of: the ability to return to play at any level (RTP), to return to the same level of play (RSL), the time to return, subsequent elbow injuries, and the need for subsequent or revision elbow surgery. The impact of the patient and surgical factors on outcomes were analyzed using multivariate linear and logistic regression modeling. Results: The overall RTP was 79.9% and RSL was 71.2%. There were no significant differences in the time to RTP or RSL based on reconstruction technique or graft type. RTP rates were similar for the Docking vs. Modified Jobe techniques (80.1% vs. 82.4%; p=0.537) and for the two primary graft types (83.1% for palmaris vs. 80.7% for gracilis; p=0.596). The risk of subsequent elbow surgery was 10.5% for the Docking Technique vs. 14.8% for the Modified Jobe (p=0.203); and the risk for subsequent UCL revision reconstruction surgery was 2.9% vs. 6.2% for the Docking vs. Modified Jobe Techniques, respectively (p=0.128). Significant trends towards an increasing use of palmaris autograft (p=0.023) and the docking technique (p=0.006) were observed. MLB pitchers were more likely than MiLB pitchers to RTP (p<0.001) and to RSL (p<0.001), but they required a longer time to return (mean difference 35 days; p=0.039), had a higher likelihood of subsequent elbow (OR 3.58; 95% CI 2.055 to 6.231; p<0.001) and forearm injuries (OR 5.695; 95% CI 1.99 to 16.302; p=0.004), but not subsequent elbow surgery. No specific variables were noted to be predictive of subsequent elbow or revision surgery in the multivariate analysis. Conclusion: Surgical outcomes in professional baseball players are not significantly influenced by ulnar collateral ligament reconstruction technique or graft type usage. Major League players are more likely to RTP and RSL, but they have a higher frequency of subsequent elbow and forearm injuries. Both the Docking Technique and palmaris autograft are increasing in popularity amongst surgeons treating professional baseball players.

Objectives: In the setting of ulnar collateral ligament (UCL) injury, surgical reconstruction of the UCL is not always selected, as it leads to a prolonged recovery time and return to play rates between 67-95%. To date, there is limited data on outcomes following nonoperative treatment in this population. Orthobiologics, such as platelet-rich plasma (PRP), have recently been used as an adjunct therapy for standard nonoperative treatment including rest and physical therapy for UCL injuries. The objective of this study was to determine if the addition of PRP injections in professional baseball players with UCL injuries reduces recovery time, lowers the likelihood of surgery, and increases the return to play rate compared to traditional nonoperative treatment. Methods: The Health and Injury Tracking System (HITS) database was searched from 2011-2015 for Major and Minor league baseball players with Grade I, II or III UCL injuries. Standard demographic, injury, and return to play data was obtained for all players. MRI’s for 353 athletes were reviewed by a musculoskeletal radiologist and graded accordingly. Outcomes were compared between players who received PRP injections in addition to traditional nonoperative treatment (PRP group) and players who received traditional nonoperative treatment alone (No PRP group). Statistical analysis was performed using Student’s T-test and Chi-square for parametric data. Kaplan Meier’s analysis was used for estimating longevity of the treatment. Results: A total of 544 Major and Minor League Baseball players with UCL tears underwent an initial course of nonoperative treatment (active rest & rehabilitation) for their injury between 2011-2015. Of these, 133 underwent PRP injections plus rehab and 411 underwent rehab alone. There was a significantly higher proportion of Major League Baseball players in the PRP group compared to the No PRP group (25.6% vs 9.0%, P<0.001). There was no difference between the two cohorts in regard to the grade of UCL tear (Figure 1). The players in the PRP group had a significantly longer time before returning to a throwing program compared to the No PRP group (64 days vs 51 days, P<0.001). The mean time from injury date to PRP injection was 14.5 days, which may explain the difference in time to return to throwing. The return to play rate in a live game without surgery was significantly lower in the PRP group compared to the No PRP group (46% vs 57%, P=0.03). There was no difference in the proportion of athletes requiring UCL reconstruction (58% vs 51%) or the time to surgery (154 days vs 178 days) between the two groups. Kaplan Meier survivor analysis showed no difference between the PRP and No PRP groups with regard to longevity of the native UCL (Figure 2). Conclusion: Among Major and Minor League Baseball players who were treated nonoperatively for a UCL injury between 2011-2015, 24% underwent PRP injections prior to rehab. Compared to traditional nonoperative rehab alone program, players who received PRP injections experienced a significantly longer time before returning to throwing, which may be in part due to the delay between the injury date and PRP injection. PRP injections did not appear to have a significant effect on the likelihood of surgical intervention.

Background Medial epicondylitis (ME), or “golfer's elbow,” is often treated initially by conservative means. Up to 15% of recalcitrant cases require surgical intervention, according to small sample populations, but no national study has determined the incidence of the diagnosis or corroborated the rate of surgical intervention. Purpose/Question We sought to review the annual incidence of ME, surgical rates, and health care costs in a population setting. Methods A national database was queried for ME from 2007 to 2014. Annual rates and the percentage of diagnosed cases subjected to surgical intervention were recorded. Epidemiologic data was reported with descriptive statistics, and the significant trends over time were analyzed using linear regression. Results We identified 19, 856 cases of ME in the study period. There was a significant increase in the annual incidence and overall incidence per 10, 000 patients. The proportion of diagnoses in patients under 65 years of age decreased significantly, while the proportion in those 65 years of age or older significantly increased. The annual number of surgical interventions significantly increased over the study period, although the annual proportion of diagnosed cases proceeding to surgery remained constant. The proportion of patients 65 years of age or older undergoing surgery significantly increased. Total reimbursement for the management of ME during the study period was $1, 877,189. While there was a significant increase in the total annual reimbursement, annual per-patient reimbursement did not change significantly. Conclusions While the annual incidence of ME and surgical treatment of ME increased significantly from 2007 to 2014, the proportion of cases treated surgically did not. Notably, the proportion of patients 65 years of age or older diagnosed with and being surgically treated for ME has increased in recent years. Total reimbursement for ME has steadily risen, although per-patient reimbursement rates have not significantly changed.

Background: As the number of cartilage restoration procedures is increasing, so is the number of revision procedures. However, there remains limited information on the reasons for failure of primary cartilage restoration procedures. Purpose: To determine the common modes of failure in primary cartilage restoration procedures to improve surgical decision making and patient outcomes. Study Design: Case series; Level of evidence, 4. Methods: Patients who presented for revision after failed cartilage repair surgery were evaluated for factors contributing to failure of the primary procedure. All revision cases performed by a single surgeon at a tertiary center for failed cartilage restoration over a 6-year time frame were identified. In all cases, the medical records, preoperative radiographs, and magnetic resonance imaging scans were reviewed by 2 experienced cartilage surgeons. The cause for failure was categorized as malalignment, meniscal deficiency, graft or biologic failure, or instability. Univariate and descriptive statistics regarding patient demographics, index procedure, lesion location and size, and mechanism of failure were analyzed. Results: A total of 59 cases in 53 patients (32 male, 21 female) met the inclusion criteria. The mean patient age at the time of revision was 27.6 years, and the mean body mass index was 28.4 kg/m 2 . Failed index surgical procedures included 35 microfractures (59%), 12 osteochondral allograft transplantations (20%), 10 osteochondral autograft transfers (17%), 2 nonviable osteochondral allografts (3%), and 2 particulated juvenile chondral allografts (3%). The mean lesion size was 4.4 cm 2 . Reasons for failure included 33 cases with untreated malalignment (56%), 16 with graft failure (27%), 11 with untreated meniscal deficiency (19%), and 3 with untreated instability (5%); 4 cases demonstrated multiple reasons for failure. Conclusion: The most commonly recognized reason for failure was untreated malalignment. While biologic and graft failures will occur, the majority of failures were attributed to untreated background factors such as malalignment, meniscal deficiency, and instability. The stepwise approach of considering and addressing alignment, meniscal volume, and stability remains essential in cartilage restoration surgery.

Background: Although batters are frequently hit by pitch (HBP) in baseball, the effect of HBP injuries remains undefined in the literature. Purpose: To determine the effect of HBP injuries in terms of time out of play, injury patterns resulting in the greatest time out of play, and the value of protective gear such as helmets and elbow pads. Study Design: Descriptive laboratory study. Methods: Based on the Major League Baseball (MLB) Health and Injury Tracking System, all injuries to batters HBP during the 2011-2015 MLB and Minor League Baseball (MiLB) seasons were identified and analyzed. Video analysis was performed on all HBP events from the 2015 MLB season. Multivariate stepwise regression analysis was utilized to determine the predictive capacity of multiple variables (velocity, pitch type, location, etc) on injury status and severity. Results: A total of 2920 HBP injuries resulted in 24,624 days missed (DM) over the 5 seasons. MLB HBP injuries occurred at a rate of 1 per 2554 plate appearances (1 per 9780 pitches thrown). Mean DM per injury were 8.4 (11.7 for MLB vs 8.0 for MiLB, P < .001). Surgery was required for 3.1% of MLB injuries and 1.2% of MiLB injuries ( P = .005). The most common body regions injured were the hand/fingers (n = 638, 21.8%), head/face (n = 497, 17.0%), and elbow (n = 440, 15.7%), and there were 146 (5.0%) concussions. Injury rates and mean DM correlated with velocity in a near linear fashion. Players hit in the head/face (odds ratio, 28.7) or distal upper extremity (odds ratio, 6.4) were more likely to be injured than players HBP in other locations. Players with an unprotected elbow missed 1.7 more days (95% CI, –4.1 to 7.6) than those with an elbow protector ( P = .554) when injured after being HBP. Conclusion/Clinical Relevance: Although HBP injuries occur infrequently in the course of normal play, they collectively represent a significant source of time out of play. The most common body regions injured include the hands/fingers and head/face, and batters hit in these locations are significantly more likely to be injured. After contusions, concussions were the most common injury diagnosis.

Background: Although cubital tunnel release is a commonly performed orthopaedic procedure, the overall incidence of and independent risk factors for infection largely remain undefined in the current literature. Purpose: To establish the rate of postoperative infection after isolated cubital tunnel release and define relevant patient-related risk factors. Study Design: Case-control study; Level 3. Methods: All Medicare-insured patients undergoing ulnar nerve decompression at the cubital tunnel from 2010 through 2012 were identified. A multivariate binomial logistic regression analysis was utilized to evaluate the impact of patient-related risk factors for postoperative infection. Results: A total of 330 (2.17%) postoperative infections were identified in 15,188 cases. The majority (87%) were managed nonoperatively, while 13% required surgical debridement. The most significant risk factors for infection included hemodialysis use (odds ratio [OR], 2.47), chronic anemia (OR, 2.24), age <65 years (OR, 2.08), tobacco use (OR, 1.65), morbid obesity (OR, 1.53), inflammatory arthritis (OR, 1.43), depression (OR, 1.36), hyperlipidemia (OR, 1.33), male sex (OR, 1.32), and chronic lung disease (OR, 1.29). Conclusion: The present study was adequately powered to determine numerous patient-related risk factors for infection following cubital tunnel release.