Clinical shoulder measurements related to joint loads in collegiate pitchers.

Background: Pitchers are prone to upper extremity injury due to repetitive high joint loads. Clinical measures of shoulder strength and range of motion (ROM) have shown links to injury risk in pitchers, however, these factors have rarely been studied in relation to throwing joint loads. The purpose of this study was to identify which clinical ROM and isokinetic strength variables were related to peak shoulder and elbow joint torques in collegiate pitchers. Methods: Thirty-three healthy collegiate pitchers participated in this study. Fastball velocity, shoulder concentric and eccentric strength, and passive shoulder ROM variables were analyzed using a Lasso regression to determine what factors influenced shoulder internal rotation torque and elbow varus torque. Results: Fastball velocity was selected by the Lasso as indicator of increased shoulder and elbow torque. Passive shoulder external rotation ROM was also selected as an important factor in joint loading with increased shoulder external rotation ROM being related to lower joint loads. The bilateral ratio of shoulder internal rotator concentric strength was related to peak shoulder and elbow torques with an increase in the bilateral ratio of shoulder strength leading to reduced joint torques. Increases in the eccentric external rotator to concentric internal rotator strength (functional ratio) of the dominant arm and increases in dominant arm eccentric internal rotator strength were both related to increases in each joint torque. Conclusion: Results from the study indicate that pitch speed, passive shoulder external rotation ROM, and the isokinetic shoulder strength profile including internal rotator strength and functional strength ratio of pitchers are related to joint loading during the pitch and may be important to monitor in relation to injury risk and/or during rehabilitation. These results provide insight into the role that both shoulder ROM and rotator cuff strength play in the dynamic stabilization of the elbow and shoulder during pitching.

Arthroscopic Repair of the Acetabular Labrum Using an Anchor-First Modified Toggle Suture Technique.

The goal of acetabular labral repair is to restore stable contact between the labrum and acetabular rim while maintaining the anatomic suction seal. One of the challenges of labral repair is achieving proper in-round repair, so that the labrum contacts the femoral head in the native position. This technique article presents a repair method that allows for enhanced inversion of the labrum to assist with anatomic repair. Our modified toggle suture technique utilizes an anchor-first method and has various distinct technical advantages. We present an efficient and vendor-agnostic technique that allows for straight or curved guides. Similarly, the anchors may be all-suture or hard-anchor designs that accommodate suture sliding. This technique also utilizes a self-retaining hand-tied knot construct to facilitate preventing knots from migrating toward the femoral head or joint space.

Prospective Randomized Controlled Clinical Trial Comparing Hyperosmolar Saline to Standard Isotonic Irrigation Fluid for Arthroscopic Knee Surgery: Initial Clinical Outcomes.

Numerous in vitro studies suggest higher osmolarity irrigation fluids potentiate a chondroprotective environment, and a recent clinical study using hyperosmolar saline for shoulder arthroscopy reported potential clinical advantages. This prospective randomized double-blind controlled clinical trial was designed to assess initial clinical outcomes associated with use of a hyperosmolar irrigation solution in patients undergoing arthroscopic knee surgery. With institutional review board approval and informed consent, patients scheduled for arthroscopic knee surgery were randomized to surgery with either isotonic lactated Ringer's (273 mOsm/L) or hyperosmolar saline (593 mOsm/L) irrigation solution. Outcomes included perioperative blood pressure, knee girth, visual analogue scale (VAS) pain scores, and narcotic pain medication consumption. Forty-six patients underwent arthroscopic knee surgery with isotonic (n = 23) or hyperosmolar (n = 23) irrigation fluids. There were 11 males and 12 females (mean age = 44.0 years) in the isotonic cohort and 8 males and 15 females (mean age = 40.2 years) in the hyperosmolar cohort. There were no significant differences with respect to surgical duration (pump time) or amount of irrigation fluid used between the two cohorts. There were no significant differences with respect to change in knee girth, blood pressure, or VAS pain scores. However, patients treated with hyperosmolar saline consumed less narcotic medication on postoperative day 3 (4.0 ± 7.6 vs. 15.5 ± 17.4 mg, p = 0.01). The results of this randomized clinical trial suggest that a hyperosmolar irrigation solution is safe and relatively inexpensive for use in patients undergoing arthroscopic knee surgery and contributes to a reduction in initial postoperative narcotic pain medication consumption. A hyperosmolar saline irrigation fluid was not associated with any detrimental effects on the execution of the surgical procedure, postoperative pain, or periarticular fluid extravasation. Taken together with previous basic science, translational, and clinical studies, hyperosmolar saline irrigation fluid is promising alternative to traditional isotonic irrigation fluids for knee arthroscopy. This study is a prospective trial and reflects level of evidence I.

Return-to-Sport Review for Current Cartilage Treatments.

The return to play outcome is an important measure for orthopaedic sports medicine treatments. This variable is especially important when discussing cartilage treatments because there are many different cartilage options available to athletes with articular injuries and this population is particularly interested in the ability to return to activities. Although many outcome variables are considered in any surgical procedure, the return-to-sport variable is focused on an active population and can be tailored to that patient's sport-specific goals. In this article, we will review some of the most recent and up-to-date articles describing return-to-sport outcomes for various knee cartilage treatments. This article will focus on the most common current knee cartilage treatments including microfracture, autologous chondrocyte implantation, osteochondral autograft transplant, and osteochondral allograft transplantation.

Sterility of 3D-Printed Orthopedic Implants Using Fused Deposition Modeling.

The use of 3-dimensional (3D) printing in orthopedics is developing rapidly and impacting the areas of preoperative planning, surgical guides, and simulation. As this technology continues to improve, the greatest impact of 3D printing may be in low- and middle-income countries where surgical items are in short supply. This study investigated sterility of 3D-printed ankle fracture fixation plates and cortical screws. The hypothesis was that the process of heated extrusion in fused deposition modeling printing would create sterile prints in a timely fashion that would not require postproduction sterilization. A free computer-assisted design program was used to design the implant models. One control group and 8 study groups were printed. Print construct, orientation, size, and postproduction sterilization differed among the groups. Sterility was assessed using thioglycollate broth cultures at 24 hours, 48 hours, and 7 days. Positive growth was speciated for aerobic and anaerobic bacteria. Print time and failed prints were recorded. Control samples were 100% positive for bacterial growth. All test samples remained sterile at all time points (100%). Speciation of control samples was obtained, and Staphylococcus was the most common species. Print times varied; however, no print time exceeded 6.75 minutes. Eighteen prints (17%) failed in the printing process. These findings demonstrate an intrinsic sterilization process associated with fused deposition modeling 3D printing and indicate the feasibility of 3D-printed surgical implants and equipment for orthopedic applications. With future research, 3D-printed implants may be a treatment modality to assist orthopedic surgeons in low- and middle-income countries. [Orthopedics. 2020; 43(1): 46-51.].

Eccentric Reaming for B2 Glenoids: History, Preoperative Planning, Surgical Technique, and Outcome.

BACKGROUND: The biconcave (B2) glenoid is characterized by preservation of the anterior portion of the native glenoid with asymmetric wear of the posterior glenoid. Surgical options for glenoid correction have evolved. The goal of shoulder arthroplasty is to place the implants in such a manner to return the humeral head to a centered position and restore the joint line to a neutral position. There is no current consensus on method of treatment and correction. METHODS: The current and historical literature on total shoulder arthroplasty was used to examine technique viability. RESULTS: Asymmetric remaining can be used to address up to 15° of version correction without compromise of cortical bone. It is important to have the proper presurgical planning, to understand the limitations of correction, and to have other options available to treat the biconcave glenoid.

Direct Visualization of Suspensory Fixation Deployment in Knee Ligament Reconstructions Without Fluoroscopic Imaging.

The authors describe a technique for visualizing the deployment of femoral suspensory fixation during ligament reconstructions that avoids the need for intraoperative fluoroscopic radiographs. Many surgeons currently use intraoperative fluoroscopic radiographs to confirm satisfactory deployment of the suspensory button on the femur; however, this technique involves prolonged surgical time, additional costs, and radiation exposure to the surgical team and patient. The authors' technique uses novel leg and camera positioning to allow for direct visualization of the button deployment. This technique can greatly improve operating room efficiency, save money, and decrease radiation exposure during surgery. [Orthopedics. 2018; 41(4):e587-e590.].

Shoulder activity level and progression of degenerative cuff disease.

BACKGROUND: This study prospectively examined the relationship of direct and indirect measures of shoulder activity with the risks of tear progression and pain development in subjects with an asymptomatic degenerative rotator cuff tear. METHODS: A cohort of asymptomatic degenerative rotator cuff tears was prospectively monitored annually, documenting tear size progression with ultrasound imaging and potential shoulder pain development. Shoulder activity level, self-reported occupational and physical demand level, and hand dominance were compared with risks of tear enlargement and future pain development. RESULTS: The study monitored 346 individuals with a mean age of 62.1 years for a median duration of 4.1 years (interquartile range [IQR], 2.4-7.9 years). Tear enlargement was seen in 177 shoulders (51.2%), and pain developed in 161 shoulders (46.5%) over time. Tear presence in the dominant shoulder was associated with a greater risk of tear enlargement (hazard ratio, 1.40; P = .03) and pain development (hazard ratio, 1.63; P = .002). Shoulder activity level (P = .37) and occupational demand level (P = .62) were not predictive of tear enlargement. Occupational demand categories of manual labor (P = .047) and "in between" (P = .045) had greater risks of pain development than sedentary demands. The median shoulder activity score for shoulders that became painful was lower than for shoulders that remained asymptomatic (10.0 [IQR, 7.0-13.0] vs. 11.0 [IQR, 8.0-14.0], P = .02). CONCLUSIONS: Tear enlargement and pain development in asymptomatic tears are more common with involvement of the dominant shoulder. Shoulder activity level is not related to tear progression risks. Pain development is associated with a lower shoulder activity level even though patients with higher occupational demands are more likely to develop pain.

"In-Round" Labral Repair After Acetabular Recession Using Intermittent Traction.

The prevalence of hip arthroscopy has increased exponentially with the advent of arthroscopic labral repair techniques for femoroacetabular impingement. The goal of arthroscopic labral repair is to re-create the anatomic suction seal of the labrum against the femoral head. This important anatomic relationship has been demonstrated in several biomechanical studies. Performing the acetabular recession and evaluating the congruity of labral repairs during surgery is difficult with the application of traction distracting the femoral head from the chondrolabral junction. Additionally, prolonged traction risks nerve injury during hip arthroscopy. The purpose of this technique article is to describe a method of using traction only for central compartment work, and releasing the traction to allow the femoral head to reduce the labrum to its anatomic position for acetabular recession, anchor placement, and suture fixation. In this manner, the presented technique prevents an "out-of-round" or everted repair. This technique re-creates the native anatomy and biomechanics of the hip after acetabular recession and labral repair while decreasing traction time.

Microstructural and Mechanical Properties of the Posterior Cruciate Ligament: A Comparison of the Anterolateral and Posteromedial Bundles.

BACKGROUND: The microstructural organization (collagen fiber alignment) of the posterior cruciate ligament (PCL), which likely corresponds with its functional properties, has only been described qualitatively in the literature, to our knowledge. The goal of this study was to quantify the tensile mechanical and microstructural properties of the PCL and compare these qualities between the anterolateral and posteromedial bundles. METHODS: Twenty-two knee specimens from 13 donors (8 male and 5 female; mean age [and standard deviation] at the time of death, 43.0 ± 4.1 years; mean body mass index, 30.0 ± 6.7 kg/m2) were dissected to isolate the PCL, and each bundle was split into 3 regions. Mechanical testing of each regional sample consisted of preconditioning followed by a ramp-and-hold stress-relaxation test and a quasi-static ramp-to-failure test. Microstructural analysis was performed with use of a high-resolution, division-of-focal-plane polarization camera to evaluate the average direction of collagen orientation and the degree to which the collagen fibers were aligned in that direction. Results were compared between the anterolateral and posteromedial bundles and across the regions of each bundle. RESULTS: The anterolateral and posteromedial bundles demonstrated largely equivalent mechanical and microstructural properties. Elastic moduli in the toe and linear regions were not different; however, the posteromedial bundle did show significantly more stress relaxation (p = 0.004). There were also few differences in microstructural properties between bundles, which again were seen only in stress relaxation. Comparing regions within each bundle, several mechanical and microstructural parameters showed significant relationships across the posteromedial bundle, following a gradient of decreasing strength and alignment from anterior to posterior. CONCLUSIONS: The PCL has relatively homogenous microstructural and mechanical properties, with few differences between the anterolateral and posteromedial bundles. This finding suggests that distinct functions of the PCL bundles result primarily from size and anatomical location rather than from differences in these properties. CLINICAL RELEVANCE: These properties of the PCL can be used to assess the utility of graft choices and operative techniques for PCL reconstruction and may partly explain limited differences in the outcomes of single-bundle compared with double-bundle reconstruction techniques for the PCL.

Pilot and Passenger Injuries Associated with Powered Parachutes.

BACKGROUND: Powered parachutes are becoming a popular form of sport flying. No previous study has reviewed injuries in this sport. The purpose of this study was to describe the injuries associated with powered parachute flying, the flight factors involved in an incident, and the impact an incident has on current sport involvement. METHODS: National Transportation Safety Board incident reports involving powered parachutes between 2004 and 2015 were reviewed. Internet searches were performed to contact involved pilots to find further information. RESULTS: There were 71 incidents reported involving 117 people. Of these, 10 incidents involved 14 fatalities (12.0%). Of the 14 fatalities, 11 (78.5%) occurred in midflight. Pilot error was the most common finding for an incident and accounted for 53/71 incidents (74.6%). The main error was misjudging the distance required for takeoff and landing. This accounted for 37/71 incidents (52.1%). Orthopedic extremity injuries were the most common severe injuries reported. Surgical intervention was needed in 43.8% of injuries and 48.0% of those involved fractures. The median return to work was 14 d (range 0-180 d). Only 4/53 (7.5%) of the pilots contacted continued to fly powered parachutes. DISCUSSION: Powered parachute participants are at risk for unique injuries compared to other forms of flight. A powered parachute injury can have a significant impact on future pilot involvement in the sport. This study provides evidence for design changes in the aircraft and helps direct pilot training. This information can improve the safety and well-being of participants so they can continue to fly powered parachutes. Skelley NW, Yarholar LM, Richardson LC. Pilot and passenger injuries associated with powered parachutes. Aerosp Med Hum Perform. 2016; 87(11):947-953.

Regional Variation in the Mechanical and Microstructural Properties of the Human Anterior Cruciate Ligament.

BACKGROUND: The anteromedial (AM) bundle of the anterior cruciate ligament (ACL) has a higher modulus and failure stress than does the posterolateral (PL) bundle. However, it is unknown how these properties vary within each bundle. PURPOSE: To quantify mechanical and microstructural properties of samples within ACL bundles to elucidate any regional variation across the ligament. We hypothesized that there are no differences within each bundle in contrast to cross-bundle variation. STUDY DESIGN: Descriptive laboratory study. METHODS: Sixteen human ACLs were dissected into AM and PL bundles. Three samples were taken from each bundle in an ordered sequence from AM (region 1 AM bundle) to PL (region 6 PL bundle). Each sample was tested in uniaxial tension, using quantitative polarized light imaging (QPLI) to quantify collagen fiber alignment. After preconditioning, samples were subjected to a stress-relaxation (SR) test followed by quasistatic ramp-to-failure (RF). Peak and equilibrium stress values were computed from the SR test and modulus quantified in the toe- and linear-regions of the RF. QPLI values describing collagen orientation (angle of polarization [AoP]) and strength of alignment (degree of linear polarization [DoLP]) were computed for the SR test and at points corresponding to the zero, transition point, and linear region of the RF. RESULTS: Toe- and linear-region modulus values decreased from region 1 to 6. Slopes of regression lines increased for the average DoLP during RF, with significance at higher strains. The standard deviation of AoP values decreased during RF, indicating tighter distribution of orientation angles, with significant correlations at all points of the RF. During SR, stress values uniformly decreased but did not show significant linear regression by region. DoLP and AoP values changed slightly during SR and demonstrated significant linear variation by region at both peak and equilibrium points. CONCLUSION: Most microstructural and material properties evaluated in this study appear to follow a linear gradient across the ACL, rather than varying by bundle. CLINICAL RELEVANCE: This AM-to-PL variation provides a more accurate description of functional tissue anatomy and can be used to assess and guide techniques of ACL reconstruction.

Microstructural properties and mechanics vary between bundles of the human anterior cruciate ligament during stress-relaxation.

Previous studies have shown different elastic properties between the anteromedial (AM) and posterolateral (PL) bundles of the human anterior cruciate ligament (ACL). However, it is unknown if the two bundles of the ACL exhibit distinct time-dependent properties and microstructural organization, which have important implications for fully understanding the structure-function relationships of this oft-injured ligament. The goal of this study was to quantify the viscoelastic material properties and collagen fiber alignment of the AM and PL bundles in 16 human ACLs during stress-relaxation mechanical tests using the quasi-linear viscoelastic (QLV) model and a quantitative polarization imaging technique. We hypothesized that the AM and PL bundles would exhibit differences in the instantaneous mechanical and organizational properties (i.e., immediately following a step increase in strain), but similar time-dependent changes during stress-relaxation. Results showed that AM samples exhibited larger peak/equilibrium stresses and less stress-relaxation during a 300-s hold compared to PL samples. The AM bundle demonstrated stronger and more uniform collagen fiber alignment (i.e., higher degree of linear polarization (DoLP) values and less distributed angle of polarization (AoP) values) compared to the PL bundle, and larger changes in alignment strength during the hold. Results suggest that the AM bundle is the more "dominant" bundle, with significantly different mechanical and material properties in stress-relaxation. While more research is needed to better understand how these findings relate to the pathophysiology of ACL tears and can best guide treatment, the findings provide additional insight into the microstructural properties and biomechanics of the human ACL.

Differences in the microstructural properties of the anteromedial and posterolateral bundles of the anterior cruciate ligament.

BACKGROUND: Tissue properties of the anteromedial (AM) and posterolateral (PL) bundles of the anterior cruciate ligament (ACL) have not been previously characterized with real-time dynamic testing. The current study used a novel polarized light technique to measure the material and microstructural properties of the ACL. HYPOTHESIS: The AM and PL bundles of the ACL have similar material and microstructural properties. STUDY DESIGN: Controlled laboratory study. METHODS: The AM and PL bundles were isolated from 16 human cadaveric ACLs (11 male, 5 female; average age, 41 years [range, 24-53 years]). Three samples from each bundle were loaded in uniaxial tension, and a custom-built polarized light imaging camera was used to quantify collagen fiber alignment in real time. A bilinear curve fit was applied to the stress-strain data of a quasistatic ramp-to-failure to quantify the moduli in the toe and linear regions. Fiber alignment was quantified at zero strain, the transition point of the bilinear fit, and in the linear portion of the stress-strain curve by computing the degree of linear polarization (DoLP) and angle of polarization (AoP), which are measures of the strength and direction of collagen alignment, respectively. Data were compared using t tests. RESULTS: The AM bundle exhibited significantly larger toe-region (AM 7.2 MPa vs. PL 4.2 MPa; P < .001) and linear-region moduli (AM 27.0 MPa vs. PL 16.1 MPa; P = .017) compared with the PL bundle. Average DoLP values were similar at low strain but were significantly larger (ie, more uniform alignment) for the AM bundle in the linear region of the stress-strain curve (AM 0.22 vs. PL 0.19; P = .036) compared with the PL bundle. The standard deviation AoP values was larger for the PL bundle at both transition (P = .041) and linear-region strain (P = .014), indicating more disperse orientation. CONCLUSION: Material and microstructural properties of the AM and PL bundles of the ACL differ during loading. The AM bundle possessed higher tissue modulus and failure stress, as well as more uniform fiber alignment under load. CLINICAL RELEVANCE: These insights into native ligament microstructure can be used to assess graft options for ACL reconstruction and optimize surgical reconstruction techniques.

A novel reduction technique for elbow dislocations.

The purpose of this study was to review a novel reduction maneuver for elbow dislocations. This was a retrospective review comparing a traditional elbow reduction method with a new single-person reduction technique. The reductions were performed during a 3-year period. Patients were evaluated in the Emergency Department of a large level I trauma center. All patients had posterolateral elbow dislocations. Sixteen patients were studied, with 6 in the traditional group and 10 in the novel single-person reduction group. All patients had successful reductions in the Emergency Department, but 2 of the patients in the traditional group were moved to the single-person reduction group after unsuccessful attempts. The traditional method required more sedations, assistance, and supplies. The authors had no nerve, vascular, or iatrogenic fractures in their series, and the technique was performed by 1 person without additional equipment. This technique is a valid option for orthopedic surgeons treating elbow dislocations.

Arthroscopic debridement and capsular release for the treatment of shoulder osteoarthritis.

PURPOSE: The purpose of this study was to evaluate patients who underwent isolated arthroscopic debridement and capsular release without any other procedures for primary glenohumeral osteoarthritis to determine clinical and functional outcomes and time until conversion to shoulder arthroplasty. METHODS: We performed a retrospective review of 33 patients who underwent arthroscopic debridement and capsular release for shoulder osteoarthritis at our institution between 2006 and 2011. All procedures were performed by a single surgeon (K.Y.). Patients were evaluated for intraoperative arthritis grade, preoperative and postoperative range or motion, American Shoulder and Elbow Surgeons (ASES) score, pain score self-assessments, radiographic evaluation, and conversion to total shoulder arthroplasty. Clinical follow-up was on average 40.3 weeks postoperatively and telephone interview follow-up was performed at a minimum of 2 years postoperatively in all patients. RESULTS: There was an initial improvement in range of motion and pain scores; however, patients in our study returned to preoperative levels approximately 3.8 months after debridement and capsular release. Twenty patients (60.6%) reported that they were not satisfied with the outcome of the procedure. Total shoulder arthroplasty was undertaken in 14 (42.4%) patients an average of 8.8 months after arthroscopy. Among the 19 (57.6%) patients who did not go on to have total shoulder arthroplasty, ASES scores (42.2 to 50.8; P = .41) and visual analog scale pain scores (7.8 to 7.4; P = .59) were similar preoperatively and at final telephone follow-up. CONCLUSIONS: Isolated arthroscopic debridement and capsular release without any other procedures were associated with only temporary pain relief and improvement in motion. Although there are limited nonarthroplasty surgical options available for glenohumeral arthritis, isolated arthroscopic debridement and capsular release may not provide substantial benefit to justify its use in most patients. LEVEL OF EVIDENCE: Level IV, therapeutic case series.