Cementation in total hip arthroplasty: history, principles, and technique.

Total hip arthroplasty (THA) is a remarkably successful operation that has grown rapidly its utilization. Early modern THA constructs as developed by Sir John Charnley featured cemented femoral stems and acetabular components. The technique of cementing components for THA has evolved over time. Modern acetabular preparation requires exposure of the subchondral bone with appropriate cement penetration into the trabecular bone, whereas femoral preparation requires cleaning of the canal, cement restrictor placement, retrograde filling, and pressurization of the cement. When used appropriately, these techniques result in excellent long-term survivorship of implants and are also widely considered to be the ideal method of fixation for hip fractures. The purpose of this article to review the history, properties, techniques, and outcomes of bone cement utilization in THA.

Comparing Revision Total Knee Arthroplasty Stems at a High-Volume Revision Center.

Introduction: Hybrid fixation and fully cemented fixation are commonly used in revision total knee arthroplasty (rTKA). These two techniques are typically done based on surgeon preference and one has not demonstrated superiority over the other. The purpose of this study was to examine if there was a difference in survivorship between the two different techniques. Methods: A retrospective cohort study of all consecutive patients undergoing rTKA (CPT 27487) from January 1, 2011 to January 1, 2018 at a single academic center was performed. Patients were divided into cemented and hybrid rTKA groups with comparison of patient demographic, clinical and radiological outcomes, reoperation, change in post-operative hemoglobin (HgB), and length of stay (LOS). Results: A total of 133 rTKA for 122 patients were identified: 30.1% in the cemented and 69.9% in the hybrid groups. There was no significant difference in age (p = 0.491), sex (p = 0.250), laterality (p = 0.421), or body mass index (BMI) (p = 0.609) between the two groups. Mean LOS (hybrid 4.13 days, cemented 3.65 days; p = 0.356) and change in Hgb (hybrid 2.95 mg/dL, cemented 2.62mg/dL; p = 0.181) were not statistically different between the groups. Mean follow up for the hybrid (25.4 months, range 2-114 months) and cemented (24.6 months, range 3-75.5 months) rTKA was not statistically significant (p = 0.825). Overall survival rates were 80.9% in the hybrid and 84.6% in the cemented groups (p = 0.642). Conclusions: Hybrid and fully cemented rTKA techniques have similar survival rates at a minimum followup of 2 years. Additionally, in our cohort, age, gender, and BMI were not associated with failure in either group. Furthermore, we did not observe differences in LOS or change in hemoglobin suggesting early postoperative complications may not differ between cemented and hybrid stemmed groups. Continued long-term research is required for defining the best rTKA technique.

Fretting and Corrosion Damage of Retrieved Dual-Mobility Total Hip Arthroplasty Systems.

BACKGROUND: Dual-mobility (DM) total hip arthroplasty (THA) systems are designed to increase stability while potentially avoiding problems associated with large femoral heads. Complications of these systems are not yet fully understood. This study aims at characterizing in vivo performance of DM hip systems and assessing modes of clinical failure. METHODS: Under an institutional review board-approved implant retrieval protocol, 18 DM THA systems from 17 patients were included. Implants were graded at the head-neck junction for fretting and corrosion based on the system of Goldberg et al. Components were also macroscopically examined for different damage modes. Demographics and surgical data were collected from medical records, and radiographs were assessed for component positioning. Data were analyzed through Spearman rank-order correlation and Mann-Whitney U-tests, with α = 0.05. RESULTS: The average length of implantation was 13.4 months with mild to moderate fretting corrosion damage. Polyethylene (PE) liners exhibited edge deformation, scratching, and pitting damage. Metallic components exhibited burnishing and scratching damage. Summed fretting and corrosion scores were strongly correlated (ρ = 0.967, P < .0001). Summed corrosion score was moderately correlated with presence of embedding on the PE liner (ρ = 0.690, P = .017). PE liner abrasion and edge deformation of the femoral stem taper were moderately positively correlated (ρ = 0.690, P = .017). Fretting and corrosion damage were not significantly correlated with patient demographics or radiographic positioning of implants. There were no differences in scores between modular and monoblock designs. CONCLUSION: These findings demonstrate that dual-mobility THA systems may be susceptible to the same fretting and corrosion damage observed in traditional modular THA systems. Future studies are needed to confirm these results and clinical significance.

Concussion rates and effects on player performance in Major League Baseball players.

BACKGROUND: Major League Baseball (MLB) players are throwing the ball faster and hitting harder than ever before. Although some safety measures have been implemented, by decreasing the 15 days on the disabled list (DL) to the 7 days on the DL, concussion rates remain high across positions and may impact player performance. Our hypothesis was, there would be an increase in concussion incidence following implementation of the 7 day DL, but this would not have a negative impact on player's postconcussion performance. STUDY DESIGN: This is a descriptive epidemiology study. METHODS: The concussed players from 2005 to 2016 were identified from the MLB DL and verified using established new sources. Position-specific performance metrics from before and after injuries were gathered and compared to assess effects of the injury. Postconcussion performance metrics were compared before and after the 7-day DL rule implementation. RESULTS: A total of 112 concussed players were placed on the DL. For all position players, the batting average (BA) and on-base percentage (OBP) showed a nonsignificant decline after injury (P=0.756). Although performance statistics for pitchers declined on average, the trend was not statistically significant. Postinjury BA and OBP did not significantly change before (0.355) and after (0.313) the 7-day DL rule change in 2011 (P=0.162). CONCLUSION: The incidence of reported concussion has increased with the 7-day DL rule change. Concussion incidence was highest in catchers and pitchers compared with all other players. The most common causes identified as being hit by pitch or struck by a foul ball or foul tip. While new league rules prevent collisions with catchers at home plate, injury by a foul tip was the most common cause for concussion. The shortened time spent on the DL did not negatively impact player's performance. Further research on protective helmets for catchers may reduce concussion incidence.

Effect of lateralized design on muscle and joint reaction forces for reverse shoulder arthroplasty.

BACKGROUND: Manufacturers of reverse shoulder arthroplasty (RSA) implants have recently designed innovative implants to optimize performance in rotator cuff-deficient shoulders. These advancements are not without tradeoffs and can have negative biomechanical effects. The objective of this study was to develop an integrated finite element analysis-kinematic model to compare the muscle forces and joint reaction forces (JRFs) of 3 different RSA designs. METHODS: A kinematic model of a normal shoulder joint was adapted from the Delft model and integrated with the well-validated OpenSim shoulder model. Static optimizations then allowed for calculation of the individual muscle forces, moment arms, and JRFs relative to net joint moments. Three-dimensional computer models of 3 RSA designs-humeral lateralized design (HLD), glenoid lateralized design, and Grammont design-were integrated, and parametric studies were performed. RESULTS: Overall, there were decreases in deltoid and rotator cuff muscle forces for all 3 RSA designs. These decreases were greatest in the middle deltoid of the HLD model for abduction and flexion and in the rotator cuff muscles under both internal rotation and external rotation. The JRFs in abduction and flexion decreased similarly for all RSA designs compared with the normal shoulder model, with the greatest decrease seen in the HLD model. CONCLUSIONS: These findings demonstrate that the design characteristics implicit in these modified RSA prostheses result in mechanical differences most prominently seen in the deltoid muscle and overall JRFs. Further research using this novel integrated model can help guide continued optimization of RSA design and clinical outcomes.

Epidemiology and location of rugby injuries treated in US emergency departments from 2004 to 2013.

Rugby participation in the US is increasing, and with its inclusion in the 2016 Summer Olympics, the increased participation rates are expected to continue. Naturally, as participation increases, so too do rugby-related injuries. The difference in injury patterns with regard to age and gender illustrates differences in how the game is being played. Understanding what accounts for these emerging injury patterns will help guide future injury prevention efforts. This study provides an update on injury rates for the growing population of rugby players in the US, especially young players. Our results focus on the variation of injury types and the injury rates of various levels of rugby players, including youth, collegiate, and recreational. Using injury data from the National Electronic Injury Surveillance System, we analyzed data in rugby patients for age, gender, body region, type of injury, and severity. We employed statistical weights to calculate national injury estimates. During the 10 years studied, the trend in the number of rugby injuries among all age groups showed a statistically significant increase (R=0.804, P=0.005). The average age of injury was 21.5±6.3 years with facial and head injuries constituting >33% of all injuries, representing a proportional increase of >10%. Men were most frequently injured in the face (18.2%) and head (15.9%); women were most frequently injured in the head (23%) and shoulder (12.3%). There were 9,059 concussions, constituting 7% of all injuries.

Effects of Cobalt and Chromium Levels Following Modular Hip Stem Total Hip Arthroplasty.

Due to the increased number of revision total hip arthroplasties (THAs) to correct pain secondary to fretting from modular hip stems, this study was conducted in an effort to correlate objective findings of serum cobalt (Co) levels, serum chromium (Cr) levels, and/or reactive tissue seen on metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) with a patient's need for revision THA. The study group comprised 66 patients, 18 of whom received MARS MRI. Serum Co levels, serum Cr levels, and standard numeric rating scale for pain were documented for all patients. Statistical analysis was then performed to determine whether there was a correlation between the aforementioned variables and the need for revision THA. Serum Cr levels were higher in patients with positive reactive tissue findings on MARS MRI, although this only approached significance (P=.083). Serum Co levels were higher in those undergoing revision THA, but this also only approached significance (P=.076). Pain scores were significantly different between those undergoing revision and those not (P<.001). It is the opinion of the authors that there is no objective finding in this study that can be used to identify patients who require revision THA secondary to fretting of a modular hip stem prosthesis. Only a patient's stated pain level can assist a surgeon in the decision-making process regarding the need for revision THA secondary to fretting. [Orthopedics.2016; 39(5):288-292.].

Return to Play and Prior Performance in Major League Baseball Pitchers After Repair of Superior Labral Anterior-Posterior Tears.

BACKGROUND: The published return-to-play (RTP) rates for Major League Baseball (MLB) pitchers who have undergone surgical repair of superior labrum anterior-posterior (SLAP) tears vary widely and are generally accepted to be lower in the subset of competitive throwers. The efficacy of surgical treatment for MLB players is largely unknown. PURPOSE: To examine the RTP rate and performance of MLB pitchers who have undergone SLAP tear repair between 2003 and 2010. STUDY DESIGN: Descriptive epidemiological study. METHODS: A retrospective review of MLB pitchers undergoing SLAP repair was performed using the MLB disabled list. Data collected included the following player statistics: earned run average (ERA), walks plus hits per inning pitched (WHIP), and innings pitched (IP). The mean values for performance variables both before and after surgery were compared. A definition of return to prior performance (RTPP) was established as an ERA within 2.00 and WHIP within 0.500 of preoperative values. RESULTS: Twenty-four MLB players met inclusion criteria, of which 62.5% were able to RTP at the MLB level after SLAP repair surgery. Of those able to RTP, 86.7% were able to RTPP. However, the overall rate of RTPP, including those unable to RTP, was 54.2%. Mean performance analysis of the RTP group revealed a statistically significant decrease in IP for MLB pitchers throwing a mean 101.8 innings before injury and 65.53 innings after injury (P = .004). CONCLUSION: Of those pitchers able to RTP, chances of a full recovery were good (86.7%). Our results indicate the need for future research aimed at proper surgical selection of who will return to play, as they will likely achieve full recovery. We believe this information can help surgeons advise high-level overhead-throwing athletes about expected outcomes for surgical treatment of SLAP tears.

The Current State of Head and Neck Injuries in Extreme Sports.

BACKGROUND: Since their conception during the mid-1970s, international participation in extreme sports has grown rapidly. The recent death of extreme snowmobiler Caleb Moore at the 2013 Winter X Games has demonstrated the serious risks associated with these sports. PURPOSE: To examine the incidence and prevalence of head and neck injuries (HNIs) in extreme sports. STUDY DESIGN: Descriptive epidemiological study. METHODS: The National Electronic Injury Surveillance System (NEISS) was used to acquire data from 7 sports (2000-2011) that were included in the Winter and Summer X Games. Data from the NEISS database were collected for each individual sport per year and type of HNI. Cumulative data for overall incidence and injuries over the entire 11-year period were calculated. National estimates were determined using NEISS-weighted calculations. Incidence rates were calculated for extreme sports using data from Outdoor Foundation Participation Reports. RESULTS: Over 4 million injuries were reported between 2000 and 2011, of which 11.3% were HNIs. Of all HNIs, 83% were head injuries and 17% neck injuries. The 4 sports with the highest total incidence of HNI were skateboarding (129,600), snowboarding (97,527), skiing (83,313), and motocross (78,236). Severe HNI (cervical or skull fracture) accounted for 2.5% of extreme sports HNIs. Of these, skateboarding had the highest percentage of severe HNIs. CONCLUSION: The number of serious injuries suffered in extreme sports has increased as participation in the sports continues to grow. A greater awareness of the dangers associated with these sports offers an opportunity for sports medicine and orthopaedic physicians to advocate for safer equipment, improved on-site medical care, and further research regarding extreme sports injuries.

Cost Analysis and Surgical Site Infection Rates in Total Knee Arthroplasty Comparing Traditional vs. Single-Use Instrumentation.

Surgical site infections (SSIs) are a significant complications in total knee arthroplasty (TKA). The purpose of this study was to evaluate if traditional vs. single-use instrumentation had an effect on SSI's. We compared SSI rates and costs of TKAs performed with single-use (449) and traditional (169) TKA instrumentation trays. Total OR Time was, on average, 30 min less when single-use instrumentation was used. SSIs decreased in the single-use group (n=1) compared to the traditional group (n=5) (P=0.006). Single-use instrumentation added $490 in initial costs; however it saved between $480 and $600. Single-use instrumentation may provide a benefit to the patient by potentially decreasing the risk of infection and reducing the overall hospital costs.

Assessment of the optimal shoulder outcome score for reverse shoulder arthroplasty.

BACKGROUND: With growing attention being paid to quality and cost-effectiveness in health care, outcome evaluations are becoming increasingly important. This determination can be especially difficult in reverse shoulder arthroplasty (RSA) given the complex pathology and extensive disabilities in this patient population. This study evaluated the use of 3 validated questionnaires used to assess outcomes for RSA. METHODS: Using a database of patients treated with RSA, we assessed preoperative and postoperative Constant-Murley Scores, American Shoulder and Elbow Surgeons Scores, and Subjective Shoulder Values in 148 shoulders. The outcomes at each scoring period were described, and the scores were compared with one another as well as with active range of motion. RESULTS: There were no significant differences in the mean improvement of any of the scores. Improvements in all of the outcome scales were correlated with each other and with improvement in forward elevation but not with external rotation. Multivariate regression analysis the 3 outcome measures was able to predict 38.9% of the variation in improvement in functional outcomes (forward elevation). This was only slightly greater than that provided by improvements in the outcome variable Constant-Murley score alone (36.7%). CONCLUSIONS: The 3 shoulder outcome scores evaluated, regardless of whether they were patient reported or physician based, appear to appropriately reflect improvements after RSA with equal validity. The objective physician-assessed Constant-Murley score had the strongest correlation with function of the arm, and use of a combination of all 3 outcome scores did not increase the ability to predict range of motion compared with using the Constant-Murley score alone.

Aberrant radial-ulnar nerve communication in the upper arm presenting as an unusual radial nerve palsy: a case report.

An unusual communication between the radial and ulnar nerves was observed during repair of a fracture of the humerus in an adult patient who presented with unusual physical exam findings. The patient had loss of radial and ulnar nerve motor function, as well as decreased sensation in both nerve distributions. Radial nerve injury following fracture of the humerus is a common condition, and anatomic variations are therefore of importance to clinicians. Communications between branches of the brachial plexus are also not uncommon findings; however there is very little mention of communication between the radial and ulnar nerves in the literature. An appreciation of unusual nerve anatomy is important in explaining unusual finding in patients.