Static stability of novel uncemented elbow hemiarthroplasty stabilized with ligament reconstruction.

BACKGROUND: The purpose of this study was to create a model to simulate treatment of unreconstructable distal humerus fractures with hemiarthroplasty. Stability was restored with a latest plate-system that simultaneously tensions medial and lateral collateral ligament grafts. MATERIALS AND METHODS: Static varus and valgus elbow stability was tested in 11 cadaver elbows with intact ligaments and capsule at 5 flexion angles (0°, 30°, 60°, 90°, 120°). The elbows were then destabilized via release of all ligaments and capsular attachments. The distal humerus articular cartilage was excised and replaced with an uncemented hemiarthroplasty. Ligament reconstruction was subsequently performed, and elbow stability was measured and compared to the native state. Dimensions of the hemiarthroplasty component were compared to native elbow dimensions to assess and quantify any existing relationship to elbow stability. RESULTS: A hemiarthroplasty was implanted in all specimens. A size mismatch occurred between the distal humerus trochlea and the olecranon fossa in all specimens and averaged 6.3 mm. Following ligament reconstruction, specimens reproduced the flexion angle-dependent stability of native elbows to both varus and valgus stress. On the medial side, elbow joint stability in mid-flexion was approximately 7% tighter after hemiarthroplasty. Laterally, the elbow was approximately 15% tighter after hemiarthroplasty and demonstrated peak stability in full flexion. The 3 assessed hemiarthroplasty components and bony dimensions did not exhibit any relationship between implant-bone mismatch and elbow stability after ligamentous reconstruction. CONCLUSION: Cadaveric elbow specimens underwent uncemented hemiarthroplasty with soft tissue stabilization with a novel technique for ligament reconstruction. Following hemiarthroplasty and ligament reconstruction, these specimens maintained secure fixation between ligament and bone. Static stability was maintained at varying degrees of elbow flexion regardless of variable mismatch between the hemiarthroplasty component and the native olecranon fossa.

Association Between Industry Sponsorship of Spine-Related Clinical Trials, Publication Status, and Research Outcomes.

STUDY DESIGN: Observational Database Study. OBJECTIVES: Prospective clinical trials in spinal surgery are expensive to conduct, especially when randomized, appropriately powered, and/or multicentered. Industry collaborations generate symbiotic relationships promoting technological advancement; however, they also allow for bias. To the authors' knowledge, there is no known analysis of correlations between industry sponsorship and publication rates of spine-related clinical trials. This observational work evaluates such potential associations. METHODS: The ClinicalTrials.gov database was queried with terms spine, spinal, spondylosis, spondylolysis, cervical, lumbar, and compression fracture over an 11-year period. Design characteristics and outcomes were recorded from 822 spine surgery-related trials. Trials were stratified based on funding source and intervention class. Groups were compared via two-tailed chi-square test of independence or Fisher's exact test (α = .05), based on completion status and publication rates of positive vs negative results. RESULTS: Industry-sponsored spine-related clinical trials were more likely to be terminated than their non-industry-sponsored counterparts (P < .001). Of the trials achieving publication, industry-sponsored trials reported positive results at a higher rate than did trials without industry funding (P = .037). Clinical trials examining devices were more likely to be terminated than those studying other intervention classes (P = .001). CONCLUSIONS: High termination rates and positive result publication rates among industry-sponsored clinical trials in spinal surgery likely reflect industry's influence on the research community. Such partnership alleviates financial burden and provides accessibility to cutting-edge innovation. It is essential that all parties remain mindful of the significant bias that funding source may impart on study outcome.

Radiographic Thumb Metacarpal Subsidence Following Ligament Reconstruction With Tendon Interposition and Suture-Only Suspension Arthroplasty in the Treatment of Basal Joint Arthritis.

BACKGROUND: The thumb carpometacarpal (CMC) joint is a common source of osteoarthritis. Following trapeziectomy, ligament reconstruction with tendon interposition (LRTI) is considered a "gold standard" treatment, but suture-only suspension arthroplasty (SSA) has recently emerged as a simpler alternative. Currently, there is no objective radiographic study comparing subsidence following these 2 techniques. METHODS: This study is a retrospective review of 23 patients (10 LRTI, 13 SSA) that had at least 6 months of radiographic follow-up following thumb CMC arthroplasty. Posteroanterior radiographs at a preoperative timepoint, and at the 2-week and greater than 6-month postoperative timepoints were evaluated for actual trapezial height, as well as trapezial height normalized to capitate, thumb metacarpal, and proximal phalangeal heights. Normalized trapezial heights were calculated, and preoperative values were compared with greater than 6-month postoperative values. In addition, actual and normalized trapezial heights following LRTI and SSA were compared at each timepoint. RESULTS: Mean trapezial height decreased from approximately 12 to 5 mm (reduction of ~60%, P < .05) in both groups with no differences when comparing LRTI and SSA at each timepoint. All normalized trapezial heights revealed differences from preoperative to greater than 6-month postoperative timepoints, but no differences between LRTI and SSA. CONCLUSIONS: Ligament reconstruction with tendon interposition and SSA exhibit equivalent actual and normalized trapezial heights over a greater than 6-month postoperative time course.

Validation of dynamic biplane radiography and three-dimensional model-based tracking for evaluation of dynamic thumb kinematics.

Dynamic biplane radiography (DBR) in conjunction with model-based tracking (MBT) has provided a suitable mechanism for biomechanical assessment of many joints but has not yet achieved widespread use at the thumb and wrist. The purpose of this work is to determine the accuracy of DBR with markerless MBT for the evaluation of thumb and wrist joint kinematics. Three 0.6 mm stainless steel beads were implanted into each trapezium, scaphoid, first metacarpal, and radius of three cadaveric upper extremities. Each specimen was manipulated in thumb abduction/adduction, thumb flexion/extension, wrist radioulnar deviation, and wrist flexion/extension while synchronized biplane radiographs were collected at 100 Hz. Specimen-specific 3D bone models were created from CT scans. MBT was performed by optimizing the correlation between digitally reconstructed radiographs, created from the volumetric CT-based bone models, and the biplane radiographs. Joint kinematics and joint space were calculated and compared between the "gold standard" bead-based tracking and markerless MBT. The MBT system accuracy (RMS error) in measuring bone position for the static and dynamic trials was 0.25 mm and 0.58 mm, respectively. The overall MBT system accuracy in measuring dynamic joint kinematics was 1.3 mm in translation and 5.0° in rotation. The MBT system accuracy in measuring dynamic joint space was 0.4 mm. DBR with MBT is a non-invasive and accurate method that can be utilized for kinematic analysis of the thumb and wrist.

Differences between men and women in coupled subtalar and tibiofemoral joint kinematics during gait revealed through dynamic biplane radiography.

It has been suggested that subtalar and tibiofemoral kinematics are coupled, such that abnormal subtalar inversion during the impact and push-off portions of stance may affect tibial rotation, leading to abnormal compensatory knee motion. This study aimed to characterize tibiofemoral and subtalar coupled motion and to determine if sex-dependent differences exist in lower extremity coupled motion. Twenty young adults were imaged at 100 frames/s using dynamic biplane radiography while walking. Lower extremity CT scans were obtained and segmented into subject-specific 3D bone models. Digitally reconstructed radiographs generated from the models were matched to the biplane radiographs via a validated tracking process to obtain tibiofemoral and subtalar joint kinematics. Subtalar inversion/eversion was strongly associated with tibiofemoral internal/external rotation and tibiofemoral ab/adduction during impact and push-off (P < 0.001). Men reached neutral subtalar and tibiofemoral orientation at midstance, while women remained more inverted at the subtalar joint and more externally rotated at the tibiofemoral joint. The rate of tibiofemoral ab/adduction to subtalar eversion differed between sexes during push-off (P = 0.005). Women underwent subtalar inversion, as well as tibiofemoral internal rotation and adduction during push-off, while men underwent only subtalar inversion and tibiofemoral internal rotation, with effectively no tibiofemoral adduction. These results provide the first quantitative evidence characterizing subtalar and tibiofemoral coupled motion. Differences in coupled motion trajectories between men and women may be associated with the higher incidence of knee-related pathology in women. These novel findings may serve as a standard for comparison when evaluating patients with patellofemoral pain.

In Vivo Evidence of Early Instability and Late Stabilization in Motion Segments Immediately Superior to Anterior Cervical Arthrodesis.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim was to identify patient factors that affect adjacent segment kinematics after anterior cervical discectomy and fusion (ACDF) as measured by biplane radiography. SUMMARY OF BACKGROUND DATA: The etiology of adjacent segment disease (ASD) may be multifactorial. Previous studies have investigated associations between patient factors and ASD, although few attempted to link patient factors with mechanical changes in the spine that may explain ASD development. Previous studies manually measured intervertebral motion from static flexion/extension radiographs, however, manual measurements are unreliable, and those studies failed to measure intervertebral motion during rotation. METHODS: Patients had continuous cervical spine flexion/extension and axial rotation movements captured at 30 images per second in a dynamic biplane radiography system preoperatively and 1 year after ACDF. Digitally reconstructed radiographs generated from subject-specific computed tomography scans were matched to the biplane radiographs using a validated tracking process. Dynamic kinematics and preoperative disc height were calculated from this tracking process. Preoperative magnetic resonance imagings were evaluated for disc bulge. Patient age, sex, body mass index, smoking status, diabetes, psychiatric history, presence of an inciting event, and length of symptoms were collected. Multivariate linear regression was performed to identify patient factors associated with 1-year postoperative changes in adjacent segment kinematics. RESULTS: Sixty-three patients completed preoperative and postoperative testing. Superior adjacent segment disc height and disc bulge predicted the change in superior adjacent segment range of motion after surgery. Inferior adjacent segment disc bulge, smoking history, and the use of psychiatric medications predicted the change in inferior adjacent segment flexion/extension range of motion after surgery. CONCLUSIONS: Preexisting adjacent segment disc degeneration, as indicated by disc height and disc bulge, was associated with reduced adjacent segment motion after ACDF, while lack of preexisting adjacent disc degeneration was associated with increased adjacent segment motion after ACDF. These findings provide in vivo evidence supporting early instability and late stabilization in the pathophysiology of disc degeneration.

Patient-specific factors, but neither regional anesthesia nor hip-specific cryotherapy, predict postoperative opioid requirements after hip arthroscopy for femoroacetabular impingement (FAI) syndrome.

Background: We sought to determine whether regional nerve block, cryotherapy variant, or patient-specific factors predict postoperative opioid requirements and pain control following hip arthroscopy. Methods: 104 patients underwent hip arthroscopy with (n = 31) or without (n = 73) regional block and received cryotherapy with a universal pad [joint non-specific; no compression (n = 60)] or circumferential hip/groin wrap with intermittent compression (n = 44). Outcomes included total opioid prescription amounts, requests for refills, and unplanned clinical encounters for postoperative pain within 45 days of surgery. Multivariate modeling was used to determine the effect of perioperative regional nerve block and type of cryotherapy device on outcomes after adjusting for patient demographics, previous opioid use, mental health disorder history, and surgery length. Results: The average amount of 5 mg oxycodone pill equivalents prescribed within 45 days of surgery was 40.5 (SD 14.8); 36% requested refills, 20% presented to another physician, and 21% called the surgeon's office due to pain. Neither the hip-specific cryotherapy pad nor regional block was predictive of opioid amounts prescribed, refill requests, or unplanned clinical encounters due to pain. Refill requests within 45 days were more common with baseline opioid use (p < 0.001), increased age (p = 0.007), and mental health disorder history (p = 0.008). Total opioid amounts prescribed within 45 days were higher with workers compensation (p = 0.03), a larger initial opioid prescription (p < 0.001), baseline opioid use (p < 0.001), history of mental health disorder (p = 0.02), and increased age (p = 0.02). Together, these variables explained 61% of the variance in opioid amounts prescribed. Conclusion: Patient factors are strong predictors of postoperative opioid requirements after hip arthroscopy. Postoperative opioid prescription amounts, opioid refill requests, and pain-related calls or office visits were not affected by use of a perioperative regional nerve block or type of cryotherapy delivery system. Level of evidence: III, retrospective cohort study.

Inpatient and outpatient opioid requirements after total joint replacement are strongly influenced by patient and surgical factors.

AIMS: Currently, there is no single, comprehensive national guideline for analgesic strategies for total joint replacement. We compared inpatient and outpatient opioid requirements following total hip arthroplasty (THA) versus total knee arthroplasty (TKA) in order to determine risk factors for increased inpatient and outpatient opioid requirements following total hip or knee arthroplasty. METHODS: Outcomes after 92 primary total knee (n = 49) and hip (n = 43) arthroplasties were analyzed. Patients with repeat surgery within 90 days were excluded. Opioid use was recorded while inpatient and 90 days postoperatively. Outcomes included total opioid use, refills, use beyond 90 days, and unplanned clinical encounters for uncontrolled pain. Multivariate modelling determined the effect of surgery, regional nerve block (RNB) or neuraxial anesthesia (NA), and non-opioid medications after adjusting for demographics, ength of stay, and baseline opioid use. RESULTS: TKAs had higher daily inpatient opioid use than THAs (in 5 mg oxycodone pill equivalents: median 12.0 vs 7.0; p < 0.001), and greater 90 day use (median 224.0 vs 100.5; p < 0.001). Opioid refills were more likely in TKA (84% vs 33%; p < 0.001). Patient who underwent TKA had higher independent risk of opioid use beyond 90 days than THA (adjusted OR 7.64; 95% SE 1.23 to 47.5; p = 0.01). Inpatient opioid use 24 hours before discharge was the strongest independent predictor of 90-day opioid use (p < 0.001). Surgical procedure, demographics, and baseline opioid use have greater influence on in/outpatient opioid demand than RNB, NA, or non-opioid analgesics. CONCLUSION: Opioid use following TKA and THA is most strongly predicted by surgical and patient factors. TKA was associated with higher postoperative opioid requirements than THA. RNB and NA did not diminish total inpatient or 90-day postoperative opioid consumption. The use of acetaminophen, gabapentin, or NSAIDs did not significantly alter inpatient opioid requirements.Cite this article: Bone Joint Open 2020;1-7:398-404.

Bone marrow lesions: etiology and pathogenesis at the hip.

Bone marrow lesions (BML) are painful changes in subchondral bone which can be reliably identified on magnetic resonance imaging and have been identified in patients suffering from hip osteoarthritis (OA) and related conditions. Created via repetitive microdamage at the articular surface and dysregulated subchondral healing, BML have been linked to traumatic, inflammatory, degenerative, metabolic and neoplastic processes. While BML are known to be a common pathology throughout the body, BML at the hip have not been extensively studied in comparison to those at the knee. Due to the hip's unique biomechanical architecture, function and loading, and independent risk factors leading to hip OA, hip BMLs must be independently understood. The identification of BML in the setting of a pre-osteoarthritic condition may provide a target for treatment and prevention of joint degeneration. By continuing to define and refine the relationships between BML, subchondral bone cysts and OA, prevention, diagnosis and treatment of OA could shift, leading to an improved quality of life and increased longevity of individuals' native hips.