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Extensor mechanism (EM) disruption after total knee arthroplasty (TKA) is devastating, especially in cases of re-rupture. A 67-year-old man with diabetes had patellar tendon rupture after revision TKA and then had migration of the bone block after Achilles tendon allograft with bone block (ATBB) augmentation with cerclage. A third reconstruction was performed with open reduction and internal fixation and high-strength braided suture augmentation. Five months postoperatively, the patient had regained full range of motion with intact EM and hardware. The risk of re-rupture is high in ATBB, and the primary issues in this case were nonunion and tendinous compromise. A construct that encompasses compression and buttressing of the bone block with tendon augmentation potentially addresses the risks of recurrent EM rupture in more complex cases. [Orthopedics. 2024;47(5):e273-e276.].

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Many bones experience bending, placing one side in net compression and the other in net tension. Because bone mechanical properties are relatively reduced in tension compared with compression, adaptations are needed to reduce fracture risk. Several toughening mechanisms exist in bone, yet little is known of the influences of secondary osteon collagen/lamellar 'morphotypes' and potential interplay with intermolecular collagen cross-links (CCLs) in prevalent/predominant tension- and compression-loaded regions. Paired third metacarpals (MC3s) from 10 adult horses were prepared for mechanical testing. From one MC3/pair, 5 mm cubes were tested in compression at several mid-shaft locations. From contralateral bones, dumbbell-shaped specimens were tested in tension. Hence, habitual/natural tension- and compression-loaded regions were tested in both modes. Data included: elastic modulus, yield and ultimate strength, and energy absorption (toughness). Fragments of tested specimens were examined for predominant collagen fiber orientation (CFO; representing osteonal and non-osteonal bone), osteon morphotype score (MTS, representing osteonal CFO), mineralization, porosity and other histological characteristics. As a consequence of insufficient material from tension-tested specimens, CCLs were only examined in compression-tested specimens (HP, hydroxylysylpyridinoline; LP, lysylpyridinoline; PE, pentosidine). Among CCLs, only LP and HP/LP correlated significantly with mechanical parameters: LP with energy absorption, HP/LP with elastic modulus (both r=0.4). HP/LP showed a trend with energy absorption (r=-0.3, P=0.08). HP/LP more strongly correlated with osteon density and mineralization than CFO or MTS. Predominant CFO more strongly correlated with energy absorption than MTS in both testing modes. In general, CFO was found to be relatively prominent in affecting regional toughness in these equine MC3s in compression and tension.

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BACKGROUND: Antiphospholipid syndrome (APS) is a systemic autoimmune condition that predisposes patients to venous thromboembolism (VTE). Although many studies have explored risk factors for VTE after joint reconstructive procedures, the impact of APS is still unclear. MATERIALS AND METHODS: A retrospective cohort study was conducted using TriNetX, a health care database that includes 442,494 patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA). Ninety-day postoperative complications and 1- and 2-year surgical complications were compared between patients with and without preexisting APS. Patients underwent propensity score matching in a 1:1 ratio based on relevant comorbidities. RESULTS: Patients undergoing THA or TKA with APS, compared with those without, had higher rates of deep venous thrombosis (hip: 9.2% vs 6.0%, odds ratio, 1.589, P=.022; knee: 10.5% vs 4.1%, odds ratio, 2.763, P<.001), pulmonary embolism (hip: 6.9% vs 3.6%, odds ratio, 1.992, P=.005; knee: 8.4% vs 3.0%, odds ratio, 2.989, P<.001), and anemia (hip: 24.8% vs 18.6%, odds ratio, 1.447, P=.004; knee: 18.5% vs 13.9%, odds ratio, 1.406, P=.007). Patients undergoing THA with APS also had higher rates of urinary tract infection (5.0% vs 2.8%, odds ratio, 1.842, P=.029) and pneumonia (3.7% vs 1.8%, odds ratio, 2.119, P=.025). APS did not impact rates of surgical complications or revision surgery. CONCLUSION: Overall, APS heightens patients' risk for complications after THA and TKA. Specific anticoagulation protocols and preoperative risk stratification should be implemented to reduce the risk of adverse events. [Orthopedics. 2024;47(5):301-307.].

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Thermal heterogeneities within energy conversion and storage, material processing, nuclear processes, aerospace, and military applications are often inaccessible to characterization by insertion sensors. When sensor deployment is possible, conventional pointwise temperature probes quickly degrade when inserted into harsh environments typical of such processes. We developed spatially-resolved ultrasonic thermometry to noninvasively measure the spatial distributions of thermal properties in such applications, even when sizable thermal gradients are present. Our method divides the path of ultrasonic propagation into segments bound by echogenic features, which create echoes in pulse-echo mode, encoding the information about interior temperature distributions. We use the acquired ultrasonic responses to estimate the internal temperature distributions by solving an inverse problem or concatenating segmental estimates. This work describes the implementation and industrial testing of the developed method at a coal-fired electrical power generation plant. We inserted an echogenically segmented Inconel 625 waveguide into the combustion zone of the utility-scale boiler and continuously acquired ultrasonic data while keeping sensitive components away from the damaging combustion environment. The accuracy of the time-dependent temperature distributions reconstructed from the ultrasonic measurements was comparable to that of thermocouples. The resiliency of ultrasonic thermometry to harsh combustion conditions was far superior to conventional insertion sensors. The measurements obtained during plant operation captured daily steam generation cycles in response to changing customer demand and intermittent contributions of renewable power sources to the power grid. These measurements have revealed new insights into the relationship between the dynamic power generation load and the conditions inside the steam generator. The successful industrial testing of spatially-resolved ultrasonic thermometry in solids indicates that the developed technology has matured to become an attractive alternative to conventional sensing in solving challenging problems of long-term thermal characterizations in extreme environments.

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The artiodactyl (deer and sheep) calcaneus is a model that helps in understanding how many bones achieve anatomical optimization and functional adaptation. We consider how the dorsal and plantar cortices of these bones are optimized in quasi-isolation (the conventional view) versus in the context of load sharing along the calcaneal shaft by "tension members" (the plantar ligament and superficial digital flexor tendon). This load-sharing concept replaces the conventional view, as we have argued in a recent publication that employs an advanced analytical model of habitual loading and fracture risk factors of the deer calcaneus. Like deer and sheep calcanei, many mammalian limb bones also experience prevalent bending, which seems problematic because the bone is weaker and less fatigue-resistant in tension than compression. To understand how bones adapt to bending loads and counteract deleterious consequences of tension, it is important to examine both strain-mode-specific (S-M-S) testing (compression testing of bone habitually loaded in compression; tension testing of bone habitually loaded in tension) and non-S-M-S testing. Mechanical testing was performed on individually machined specimens from the dorsal "compression cortex" and plantar "tension cortex" of adult deer calcanei and were independently tested to failure in one of these two strain modes. We hypothesized that the mechanical properties of each cortex region would be optimized for its habitual strain mode when these regions are considered independently. Consistent with this hypothesis, energy absorption parameters were approximately three times greater in S-M-S compression testing in the dorsal/compression cortex when compared to non-S-M-S tension testing of the dorsal cortex. However, inconsistent with this hypothesis, S-M-S tension testing of the plantar/tension cortex did not show greater energy absorption compared to non-S-M-S compression testing of the plantar cortex. When compared to the dorsal cortex, the plantar cortex only had a higher elastic modulus (in S-M-S testing of both regions). Therefore, the greater strength and capacity for energy absorption of the dorsal cortex might "protect" the weaker plantar cortex during functional loading. However, this conventional interpretation (i.e., considering adaptation of each cortex in isolation) is rejected when critically considering the load-sharing influences of the ligament and tendon that course along the plantar cortex. This important finding/interpretation has general implications for a better understanding of how other similarly loaded bones achieve anatomical optimization and functional adaptation.

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The mechanobiology of the human femoral neck is a focus of research for many reasons including studies that aim to curb age-related bone loss that contributes to a near-exponential rate of hip fractures. Many believe that the femoral neck is often loaded in rather simple bending, which causes net tension stress in the upper (superior) femoral neck and net compression stress in its inferior aspect ("T/C paradigm"). This T/C loading regime lacks in vivo proof. The "C/C paradigm" is a plausible alternative simplified load history that is characterized by a gradient of net compression across the entire femoral neck; action of the gluteus medius and external rotators of the hip are important in this context. It is unclear which paradigm is at play in natural loading due to lack of in vivo bone strain data and deficiencies in understanding mechanisms and manifestations of bone adaptation in tension vs. compression. For these reasons, studies of the femoral neck would benefit from being compared to a 'control bone' that has been proven, by strain data, to be habitually loaded in bending. The artiodactyl (sheep and deer) calcaneus model has been shown to be a very suitable control in this context. However, the application of this control in understanding the load history of the femoral neck has only been attempted in two prior studies, which did not examine the interplay between cortical and trabecular bone, or potential load-sharing influences of tendons and ligaments. Our first goal is to compare fracture risk factors of the femoral neck in both paradigms. Our second goal is to compare and contrast the deer calcaneus to the human femoral neck in terms of fracture risk factors in the T/C paradigm (the C/C paradigm is not applicable in the artiodactyl calcaneus due to its highly constrained loading). Our third goal explores interplay between dorsal/compression and plantar/tension regions of the deer calcaneus and the load-sharing roles of a nearby ligament and tendon, with insights for translation to the femoral neck. These goals were achieved by employing the analytical model of Fox and Keaveny (J. Theoretical Biology 2001, 2003) that estimates fracture risk factors of the femoral neck. This model focuses on biomechanical advantages of the asymmetric distribution of cortical bone in the direction of habitual loading. The cortical thickness asymmetry of the femoral neck (thin superior cortex, thick inferior cortex) reflects the superior-inferior placement of trabecular bone (i.e., "trabecular eccentricity," TE). TE helps the femoral neck adapt to typical stresses and strains through load-sharing between superior and inferior cortices. Our goals were evaluated in the context of TE. Results showed the C/C paradigm has lower risk factors for the superior cortex and for the overall femoral neck, which is clinically relevant. TE analyses of the deer calcaneus revealed important synergism in load-sharing between the plantar/tension cortex and adjacent ligament/tendon, which challenges conventional understanding of how this control bone achieves functional adaptation. Comparisons with the control bone also exposed important deficiencies in current understanding of human femoral neck loading and its potential histocompositional adaptations.

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Loss of quadriceps strength after total knee arthroplasty (TKA) is most pronounced acutely but persists long-term, negatively impacting physical function in daily activities. Neuromuscular electrical stimulation (NMES) early after surgery is an effective adjuvant to standard of care rehabilitation (SOC) for attenuating strength loss following TKA, but the mechanisms whereby NMES maintains strength are unclear. This work aimed to determine the effects of early NMES on quadriceps strength and skeletal muscle fiber size 2 weeks after TKA compared to SOC. Patients scheduled for primary, unilateral TKA were enrolled and randomized into SOC (n = 9) or NMES plus SOC (n = 10) groups. NMES was started within 48 h of TKA, with 45-min sessions twice a day for 2 weeks. Isometric quadriceps strength was assessed preoperatively and 2 weeks following TKA. Vastus lateralis muscle biopsies of the involved leg were performed at the same time points and immunohistochemistry conducted to assess muscle fiber cross-sectional area and distinguish fiber types. Groups did not differ in age, body mass index, sex distribution, or preoperative strength. Both groups got weaker postoperatively, but the NMES group had higher normalized strength. After 2 weeks, the group receiving NMES and SOC had significantly greater MHC IIA and MHC IIA/IIX fiber size compared to SOC alone, with no group differences in MHC I fiber size. These results suggest that NMES mitigates early muscle weakness following TKA, in part, via effects on fast-twitch, type II muscle fiber size. This investigation advances our understanding of how adjuvant, early postoperative NMES aids muscle strength recovery.

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BACKGROUND: The aim of our study was to evaluate whether an association exists between body mass index (BMI) category and post-operative opioid requirements among primary total joint arthroplasty (TJA) patients. METHODS: We retrospectively reviewed all primary unilateral total hip and total knee arthroplasty (THA/TKA, respectively) cases performed over a two-year period. We evaluated whether a relationship exists between five BMI categories (≤24.9, 25-29.9, 30-34.9, 35-39.9, ≥40) and morphine milligram equivalent (MME) use for total in-hospital, daily in-hospital, and total during six weeks post-discharge. Secondary outcomes included relationship with length of stay, discharge location, opioid refill rate, and pre-operative opioid usage. RESULTS: For all patients undergoing primary TJA, increasing BMI resulted in an incremental increase in post-operative total in-hospital MME use for each successive BMI category when compared to those with BMI ≤24.9 (p < 0.05). This association held true for the THA subset. Within the cohort as a whole, higher categories of BMI were associated with increased length of stay (35-39.9, ≥40), higher odds of needing a refill (30-34.9, 35-39.9, ≥40), and higher odds of discharging to a rehab facility (25-29.9, ≥40) (p < 0.05). There was an increasing proportion of pre-operative opioid use as BMI category increased (p < 0.0001). DISCUSSION/CONCLUSION: BMI category is associated with increased in-hospital opioid requirements among primary TJA patients. Such findings are an important step to better understanding pain control expectations and can help facilitate development of opioid reduction strategies.

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INTRODUCTION: Total knee arthroplasty (TKA) reduces joint symptoms, but habitual movement compensations persist years after surgery. Preliminary research on movement training interventions have signaled initial efficacy for remediating movement compensations and restoring knee joint loading symmetry during dynamic functional tasks after TKA. The purpose of this clinical trial is to determine if physical rehabilitation that includes movement training restores healthy movement patterns after TKA and reduces the risk of osteoarthritis (OA) progression in the contralateral knee. METHODS/DESIGN: 150 participants will be enrolled into this randomized controlled trial. Participants will be randomly allocated to one of two dose-equivalent treatment groups: standard rehabilitation plus movement training (MOVE) or standard rehabilitation without movement training (CONTROL). Movement training will promote between-limb symmetry and surgical knee loading during activity-based exercises. Movement training strategies will include real-time biofeedback using in-shoe pressure sensors and verbal, visual, and tactile cues from the physical therapist. The primary outcome will be change in peak knee extension moment in the surgical knee during walking, from before surgery to six months after surgery. Secondary outcomes will include lower extremity movement symmetry during functional tasks, physical function, quadriceps strength, range of motion, satisfaction, adherence, contralateral knee OA progression, and incidence of contralateral TKA. DISCUSSION: This study will provide insights into the efficacy of movement training after unilateral TKA, along with mechanisms for optimizing long-term physical function and minimizing negative sequelae of compensatory movement patterns.

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Purpose: To investigate the effectiveness of home health physical therapy followed by outpatient physical therapy as compared to patients discharged directly to outpatient physical therapy in improving functional performance, strength/activation and residual knee pain outcomes among patients who received a total knee arthroplasty.Materials and methods: A secondary analysis of longitudinal data in which patients with total knee arthroplasty underwent home health physical therapy or were discharged directly to outpatient physical therapy. Main outcome measures included the stair climb test, timed up and go, 6-min walk test, quadriceps and hamstring strength, quadriceps activation and residual knee pain.Results: Patients referred to home health physical therapy prior to outpatient physical therapy demonstrated significantly greater declines in stair climb test (10.3; 95% CI [6.5, 14.1]; t = 5.41; p < 0.0001), timed up and go (2.0; 95% CI [1.0, 3.0]; t = 4.10; p < 0.0001), 6-min walk (53.8; 95% CI [29.4, 78.2]; t = 4.35; p < 0.0001), quadriceps strength (21.7%; 95% CI [19.3%, 24.9%]; t = 2.53; p = 0.01), hamstring strength (44.7%; 95% CI [43.4%, 45.7%], t = 3.17; p = 0.002) and higher residual knee pain (0.53; 95% CI [0.04, 1.03]; t = 2.17; p = 0.03) 1 month after total knee arthroplasty compared to those referred directly to outpatient physical therapy.Conclusions: These findings suggest that patients discharged directly to outpatient physical therapy had a more rapid recovery 1 month after total knee arthroplasty. Additional research is needed to investigate the potential causal relation between care pathways and clinical outcomes following total knee arthroplasty.Implications for rehabilitationTotal knee arthroplasty, typically performed to alleviate end-stage knee osteoarthritis, is the most commonly performed elective surgery in the United States.Despite improvement in pain, objective measurements of functional performance and strength often remain at preoperative levels one year after total knee arthroplasty.Patients discharged directly to higher intensity outpatient physical therapy have a more rapid recovery after total knee arthroplasty compared with those patients who received two weeks of home health prior to undergoing outpatient physical therapy.

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BACKGROUND: Quadriceps weakness is a hallmark of total knee arthroplasty and is driven by reduced voluntary muscle activation following the surgical procedure. The mechanisms underlying postoperative activation deficits are not well established, although nociception has been implicated via both spinal reflex and supraspinal pathways. The purpose of this study was to assess the role of nociception in postoperative recovery of strength and activation. METHODS: A total of 53 participants were assessed prior to total knee arthroplasty and at 6 weeks postoperatively. Quadriceps strength was measured by maximum voluntary isometric contraction, and activation was measured by the doublet interpolation technique. The pressure-pain threshold was used to measure local sensitization (at the knee joint) and systemic sensitization (at the forearm). Changes in outcomes (strength and activation) were regressed against pressure-pain threshold measurements. Mediation analyses were planned for significant associations to investigate whether deficits in voluntary activation were implicated on a causal pathway between pressure-pain threshold measures and postoperative strength loss. RESULTS: Knee pressure-pain threshold measures were significantly associated with reduced voluntary quadriceps activation (beta = -0.04; p = 0.009) and diminished quadriceps strength after total knee arthroplasty (beta = -0.07; p = 0.001). There was also a mediation effect of voluntary activation on the relationship between the knee pressure-pain threshold and quadriceps strength. After correcting for multiple comparisons, relationships between the forearm pressure-pain threshold and strength and activation did not reach significance. CONCLUSIONS: The measures of local nociceptor sensitization were related to reduced strength and activation following total knee arthroplasty. This is consistent with a causal pathway linking increased firing of knee joint nociceptors to reduced activation and reduced strength. Future randomized studies should investigate whether peripherally directed pain therapies reduce pain while also promoting the recovery of quadriceps strength via an improved capacity for voluntary activation. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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Total joint replacement is indicated to alleviate pain and disability associated with hip and knee osteoarthritis. Arthroplasty outcomes are typically reported together, or anecdotal comparisons are made between total knee arthroplasty (TKA) and total hip arthroplasty (THA) recovery. Limited data quantifies differences in recovery trajectories, especially with respect to performance-based outcomes. Seventy-nine people undergoing total knee or THA were followed over 6 months. Functional performance was measured using the stair climb test, timed-up-and-go test, and 6-min walk test. Surgical limb isometric strength was also measured. All outcomes significantly declined 1 month after surgery. Participants in the TKA group showed a greater decline in climbing stairs (P < 0.001), timed-up-and-go (P = 0.01), and 6-min walk distance (P < 0.01). Further, the TKA group lost more strength (P < 0.001) and were weaker than those after THA (P < 0.001). Differences in postoperative outcomes between groups at 3 and 6 months were also observed. The TKA group experiences a greater decline in measured outcomes than the THA group, and muscle strength and functional recovery occurred differently in each group. These findings should be considered in rehabilitation priorities after arthroplasty surgery.

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BACKGROUND: The sequence of posterior cruciate ligament (PCL) release in posterior-substituting designs, when performing gap balancing in total knee arthroplasty (TKA), is variable. We hypothesize that early complete PCL release during knee exposure will change the flexion balance to result in a uniform medial-lateral flexion gap symmetry at the time of implant placement. METHODS: Ten cadaveric knees were prepared for TKA using standard medial parapatellar approach. Medial and lateral flexion gaps were measured in the conditions of intact, partial (50%) resection, and full resection of PCL. Measurements were performed with both surgical navigation and a caliper. Flexion gap distances were reported for medial and lateral compartments in the 3 PCL conditions. RESULTS: Medial flexion gap increased after only complete release of the PCL (mean 3.94-5.05 mm). The lateral flexion gap increased as well (mean 4.17-4.67 mm). Complete PCL release resulted in a statistically significant increase in medial flexion gap compared to intact (P = .013) and partially released (P = .012) specimens. No significant differences were noted in lateral flexion gap change. Notable change in medial versus lateral gap (flexion gap symmetry) relationship occurred after just partial PCL release (P = .018). CONCLUSION: Among the 3 PCL states, changes in flexion gap distance were most conspicuous in the medial compartment. This suggests gap balancing performed with incomplete PCL release will not accurately reflect gap distance after eventual PCL removal, thus supporting the hypothesis. It is recommended that the PCL should be released to the fullest extent possible before ligament tensioning for femoral component rotation in posterior-stabilized TKA.

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BACKGROUND: The relationships between swelling after total knee arthroplasty (TKA) and quadriceps strength and functional performance are poorly understood. Therefore, the aim of this study was to examine the relationships between lower extremity swelling, measured using bioelectrical impedance assessment (SF-BIA), and quadriceps strength and timed up and go (TUG) times following TKA. METHODS: 53 participants (64 ±â€¯9.5 y/o, 43% male) undergoing primary unilateral TKA were recruited for the longitudinal observational study with repeated measures. Quantities of swelling were examined for contribution to two and six-week outcomes of strength and TUG time using hierarchical regression controlling for age, sex, and the baseline value of the dependent variable. Swelling was assessed using bioelectrical impedance assessment and quantified as the peak level of swelling and cumulative swelling (integral) over the post-TKA time window. Maximum isometric quadriceps strength (MVIC) was measured using a electromechanical dynamometer and participant functional performance measured using the TUG. RESULTS: Neither peak swelling nor cumulative swelling significantly contributed to the variance of two-week quadriceps strength. At six weeks, peak swelling significantly improved the variance in maximal quadriceps strength by an additional four percent (p = 0.05), while cumulative swelling did not significantly contribute. Peak swelling significantly contributed to the variance in two-week (16%) and six-week (five percent) TUG times (p < 0.05), but the cumulative swelling did not. CONCLUSIONS: Peak swelling represents a value of post-TKA swelling that is associated with strength and function. Reducing the peak level of swelling, occurring early after surgery, may improve patient functional recovery. LEVEL OF EVIDENCE: Level II - Prospective observational study.

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Medial compartment knee osteoarthritis is a painful and debilitating disease. A proximal fibular osteotomy is a novel, simple surgical technique that may reduce pain and improve function for patients with osteoarthritis. The purpose of this biomechanical cadaver study was to determine what effect proximal fibular osteotomy had on knee joint and ankle pressures and tibia strain. Ten matched pairs of cadaver legs were tested in compression to 1.1 times body weight comparing intact and with proximal fibular osteotomy at 0°, 15°, and 30° of flexion. Sensors were inserted into the knee and ankle joint to measure pressure, force, and contact area. Strain was measured with a strain gage on the anterior medial tibia. In the medial compartment, the peak force, contact area, and pressure all decreased from intact to after fibular osteotomy, with significant differences at 15° of flexion (P<.05). There were no significant differences in the lateral compartment for any measures. In the ankle joint, the peak force and pressure decreased from intact to after fibular osteotomy at all 3 flexion angles. There were no significant changes in strain in the tibia. Proximal fibular osteotomy decreases the pressure in the medial compartment of the knee, which may reduce knee pain and improve function in patients with medial compartment knee osteoarthritis. [Orthopedics. 2018; 41(4):e496-e501.].

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The original publication of this paper contain an error. The author name "Alan S. McGee Jr" is incorrect for it should have been "Alan W. McGee Jr".

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PURPOSE: To determine if lumbar fusion increases the risk of dislocation following total hip arthroplasty (THA) via a posterior approach and to investigate anatomic variables associated with this increased risk. METHODS: Five-year retrospective review of THAs performed through a posterior approach identifying cases of post-operative dislocation. Patients were grouped into those with or without previous lumbar spine fusion. Lumbar fusion patients were then further analyzed in terms of cup position, pelvic incidence, sacral slope, and pelvic tilt to determine if there were specific variables associated with the increased risk of dislocation. RESULTS: Five hundred nine primary THAs in 460 patients (non-simultaneous bilateral THAs in 41 patients) met inclusion criteria with a dislocation rate of 5.5%. Thirty-one patients were identified as having prior lumbar fusions. The dislocation rate was significantly higher in fusion patients (29 vs 4%; p = 0.009) yielding a relative risk (RR) of dislocation of 4.77 (p = < 0.0001). Additionally, cup anteversion was significantly different between groups (26.8 vs 21.42; p = 0.009). Dislocators in the fusion group were also at greater risk of requiring subsequent revision (RR = 3.24; p = 0.003). Subgroup analysis of fusion patients revealed that dislocators had lower pelvic incidence and sacral slope compared to non-dislocators (45.2 vs 58.6 [p = 0.0029] and 26.3 vs 35.6 [p = 0.0384] respectively). CONCLUSIONS: Patients with lumbar fusion are at increased risk for post-operative dislocations requiring revision. Together, lower pelvic incidence and decreased sacral slope are associated with increased risk of dislocation in these patients.

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INTRODUCTION: The purpose of this study was to analyze how program directors (PDs) of orthopaedic surgery residency programs use United States Medical Licensing Examination (USMLE) Step 1 and 2 scores in screening residency applicants. METHODS: A survey was sent to each allopathic orthopaedic surgery residency PD. PDs were asked if they currently use minimum Step 1 and/or 2 scores in screening residency applicants and if these criteria have changed in recent years. RESULTS: Responses were received from 113 of 151 PDs (75%). One program did not have the requested information and five declined participation, leaving 107 responses analyzed. Eighty-nine programs used a minimum USMLE Step 1 score (83%). Eighty-three programs (78%) required a Step 1 score ≥210, 80 (75%) required a score ≥220, 57 (53%) required a score ≥230, and 22 (21%) required a score ≥240. Multiple PDs mentioned the high volume of applications as a reason for using a minimum score and for increasing the minimum score in recent years. DISCUSSION: A large proportion of orthopaedic surgery residency PDs use a USMLE Step 1 minimum score when screening applications in an effort to reduce the number of applications to be reviewed.

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BACKGROUND: Forced-air warming is used as a mechanism to prevent hypothermia and adverse outcomes associated with hypothermia among patients undergoing surgery. Patient safety in healthcare includes the use of devices and technology that minimize potential adverse events to patients. The present study sought to compare the capabilities of patient warming between two different devices that use different mechanisms of warming: forced-air warming and non-air warming. METHODS: One hundred twenty patients undergoing total hip or total knee arthroplasty received patient warming via a forced warming device or non-air warming fabric conductive material. The project was part of a quality improvement initiative to identify warming devices effective in maintaining normothermic patient core temperatures during orthopedic surgery. RESULTS: Forced-air warming and non-air warming achieved similar results in maintaining the core temperature of patients undergoing total knee or hip arthroplasty. No adverse events were reported in either group. Operating room staff observed that the non-air warming device was less noisy and appreciated the disposable covers that could be changed after each surgical case. CONCLUSIONS: These findings demonstrate that hypothermia is achieved by both forced-air and non-forced air warming devices among total knee and hip arthroplasty patients. The potential for airflow disruption is present with the forced-air warming device and does not exist with the non-forced air device. The disruption of laminar airflow may be associated with surgical site infections. The disposable covers used to protect the device and patient have potential implications for surgical site infection. Quality improvement efforts aimed to enhance patient safety should include the implementation of healthcare equipment with the least known or suspected risk.

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BACKGROUND: The Association of American Medical Colleges publishes residency match data and reports through the National Resident Matching Program (NRMP) every year. The purpose of this study was to analyze trends in orthopaedic surgery residency matching data and characteristics of successful applicants to counsel medical students with regard to their chances of matching. METHODS: The annual reports of the NRMP were searched annually from 2006 to 2014 to determine the number of orthopaedic surgery residency positions available, the number of applicants, and the match rate among applicants. Comparisons were performed between matched applicants and unmatched applicants with regard to the number of contiguous ranks and distinct specialties, United States Medical Licensing Examination (USMLE) scores, number of research experiences and research products (abstracts, presentations, posters, publications), and proportion of Alpha Omega Alpha (AOA) Honor Medical Society members and students at a top-40, National Institutes of Health (NIH)-funded medical school. RESULTS: The number of orthopaedic surgery positions available and number of applicants increased at a mean rate of 9 positions and 65 applicants per year (p = 0.11). The mean number of contiguous ranks for U.S. senior medical students was 11.5 for those who matched and 5.5 for those who did not match (p < 0.0001). The USMLE scores for applicants who matched were significantly greater than for those who did not match in each category: Step-1 scores for U.S. seniors (p < 0.001) and independent applicants (p = 0.039), and Step-2 scores for U.S. seniors (p < 0.01) and independent applicants (p = 0.026). The mean number of research products was significantly greater for matched U.S. seniors compared with unmatched U.S. seniors (p = 0.035). A significantly higher proportion of matched U.S. seniors compared with unmatched U.S. seniors were AOA members and students at a top-40, NIH-funded medical school (both p < 0.0001). CONCLUSIONS: Successful applicants in the Match for orthopaedic surgery residency have higher USMLE Step-1 and 2 scores, number of research experiences and research products, and contiguous ranks. A higher proportion of successful applicants are AOA members and students at a top-40, NIH-funded medical school.

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