Fourier Analysis of the Vertical Ground Reaction Force During Walking: Applications for Quantifying Differences in Gait Strategies.

Time series biomechanical data inform our understanding of normal gait mechanics and pathomechanics. This study examines the utility of different quantitative methods to distinguish vertical ground reaction forces (VGRFs) from experimentally distinct gait strategies. The goals of this study are to compare measures of VGRF data-using the shape factor method and a Fourier series-based analysis-to (1) describe how these methods reflect and distinguish gait patterns and (2) determine which Fourier series coefficients discriminate normal walking, with a relatively stiff-legged gait, from compliant walking, using deep knee flexion and limited vertical oscillation. This study includes a reanalysis of previously presented VGRF data. We applied the shape factor method and fit 3- to 8-term Fourier series to zero-padded VGRF data. We compared VGRF renderings using Euclidean L2 distances and correlations stratified by gait strategy. Euclidean L2 distances improved with additional harmonics, with limited improvement after the seventh term. Euclidean L2 distances were greater in shape factor versus Fourier series renderings. In the 8 harmonic model, amplitudes of 9 Fourier coefficients-which contribute to VGRF features including peak and local minimum amplitudes and limb loading rates-were different between normal and compliant walking. The results suggest that Fourier series-based methods distinguish between gait strategies.

Bilateral lunotriquetral coalition: a dynamic four-dimensional computed tomography technical case report.

Lunotriquetral coalitions are the most common form of carpal coalition wherein the cartilage between the lunate and triquetrum ossification centers failed to undergo apoptosis. This technical case report examines the arthrokinematics of bilateral lunotriquetral coalitions with dissimilar Minnaar types in one participant with one asymptomatic wrist and one wrist with suspected distal radioulnar joint injury. Static and dynamic (four-dimensional) CT images during pronosupination were captured using a photon-counting detector CT scanner. Interosseous proximity distributions were calculated between the lunotriquetral coalition and adjacent bones in both wrists to quantify arthrokinematics. Interosseous proximity distributions at joints adjacent to the lunotriquetral coalition demonstrate differences in median and minimum interosseous proximities between the asymptomatic and injured wrists during resisted pronosupination. Altered kinematics from lunotriquetral coalitions may be a source of ulnar-sided wrist pain and discomfort, limiting the functional range of motion. This case report highlights potential alterations to wrist arthrokinematics in the setting of lunotriquetral coalitions and possible associations with ulnar-sided wrist pain, highlighting anatomy to examine in radiographic follow-up. Furthermore, this case report demonstrates the technical feasibility of four-dimensional CT using photon-counting detector technology in assessing arthrokinematics in the setting of variant wrist anatomy.

Assessing carpal kinematics following scapholunate interosseous ligament injury ex vivo using four-dimensional dynamic computed tomography.

BACKGROUND: Scapholunate interosseous ligament injuries are prevalent and often challenging to diagnose radiographically. Four-dimensional CT allows visualization of carpal bones during motion. We present a cadaveric model of sequential ligamentous sectionings ("injuries") to quantify their effects on interosseous proximities at the radioscaphoid joint and scapholunate interval. We hypothesized that injury, wrist position, and their interaction affect carpal arthrokinematics. METHODS: Eight cadaveric wrists were moved through flexion-extension and radioulnar deviation after injuries. Dynamic CT images of each motion were acquired in each injury condition using a second-generation dual-source CT scanner. Carpal osteokinematics were used to calculate arthrokinematic interosseous proximity distributions during motion. Median interosseous proximities were normalized and categorized by wrist position. Linear mixed-effects models and marginal means tests were used to compare distributions of median interosseous proximities. FINDINGS: The effect of wrist position was significant for both flexion-extension and radioulnar deviation at the radioscaphoid joint; the effect of injury was significant for flexion-extension at the scapholunate interval; and the effect of their interaction was significant for radioulnar deviation at the scapholunate interval. Across wrist positions, radioscaphoid median interosseous proximities were less able to distinguish injury conditions versus scapholunate proximities. Median interosseous proximities at the scapholunate interval are majoritively able to detect differences between less (Geissler I-III) versus more (Geissler IV) severe injuries when the wrist is flexed, extended, and ulnarly-deviated. INTERPRETATION: Dynamic CT enhances our understanding of carpal arthrokinematics in a cadaveric model of SLIL injury. Scapholunate median interosseous proximities in flexion, extension, and ulnar deviation best demonstrate ligamentous integrity.

Evaluation of Scapholunate Injury and Repair with Dynamic (4D) CT: A Preliminary Report of Two Cases.

Background In predynamic or dynamic scapholunate (SL) instability, standard diagnostic imaging may not identify SL interosseous ligament (SLIL) injury, leading to delayed detection and intervention. This study describes the use of four-dimensional computed tomography (4DCT) in identifying early SLIL injury and following injured wrists to 1-year postoperatively. Description of Technique 4DCT acquires a series of three-dimensional volume data with high temporal resolution (66 ms). 4DCT-derived arthrokinematic data can be used as biomarkers of ligament integrity. Patients and Methods This study presents the use of 4DCT in a two-participant case series to assess changes in arthrokinematics following unilateral SLIL injury preoperatively and 1-year postoperatively. Patients were treated with volar ligament repair with volar capsulodesis and arthroscopic dorsal capsulodesis. Arthrokinematics were compared between uninjured, preoperative injured, and postoperative injured (repaired) wrists. Results 4DCT detected changes in interosseous distances during flexion-extension and radioulnar deviation. Generally, radioscaphoid joint distances were greatest in the uninjured wrist during flexion-extension and radioulnar deviation, and SL interval distances were smallest in the uninjured wrist during flexion-extension and radioulnar deviation. Conclusion 4DCT provides insight into carpal arthrokinematics during motion. Distances between the radioscaphoid joint and SL interval can be displayed as proximity maps or as simplified descriptive statistics to facilitate comparisons between wrists and time points. These data offer insight into areas of concern for decreased interosseous distance and increased intercarpal diastasis. This method may allow surgeons to assess whether (1) injury can be visualized during motion, (2) surgery repaired the injury, and (3) surgery restored normal carpal motion. Level of Evidence Level IV, Case series.

Prevalence of accessory sacroiliac joint anatomy and associated clinical features.

OBJECTIVE: The accessory sacroiliac joint (ASIJ) is the most common sacroiliac joint anatomical variant; however, its literature-reported prevalence is inconsistent. Previous CT-based studies of the ASIJ have used thick axial slices, which may not adequately detail ASIJ anatomy. The aims of this study are to (1) evaluate ASIJ prevalence and radiographic features in a large age- and sex-balanced cohort using thin-section CT and (2) determine associations between ASIJ anatomy, patient features, and treatment strategies. MATERIALS AND METHODS: Thin-section CTs (0.75 to 2.00 mm) of the pelvis from 800 patients were reviewed by two musculoskeletal radiologists. Degree of degenerative change and ankylosis at ASIJs were detailed. The EMR was used to capture demographics, lower back or sacroiliac joint symptoms, and treatments. RESULTS: The ASIJ was present in 25.8% of patients and bilateral in 53.3% of those with any ASIJ. ASIJs were more common at the S2 than S1 neural foramen level (75.7% and 27.2%). There was a statistically significant difference between age and presence of any ASIJ anatomy (mean (SD) 69.0 (19.8) with ASIJ versus 55.9 (22.1) years without ASIJ). Degenerative changes and ankylosis were found in 93.5% and 20.3% of ASIJs, respectively. There was a higher odds ratio of having received a sacroiliac joint corticosteroid injection in those with ASIJ anatomy. CONCLUSION: Radiologists should be familiar with the ASIJ and consider its age-related association, propensity to show ASIJ degenerative change, and ability to serve as a potential pain generator. Steroid injections may be considered for diagnostic and therapeutic purposes.

A Comparison of Outcomes following Plate versus Pin Fixation of Metacarpal Shaft and Neck Fractures.

The aim of this study is to compare clinical and radiographic outcomes of open reduction and internal fixation versus closed reduction and percutaneous pinning of metacarpal fractures in relation to anatomic and surgical variables. Methods: Electronic medical records at two institutions were reviewed for patients who underwent surgical intervention for metacarpal fractures. Data were collected from those who underwent reduction and internal fixation with either plates or Kirschner wires (K-wires). Inclusion criteria included minimum postoperative follow-up of 60 days and age 18 years or older. Exclusion criteria included insufficient radiographic data, previously attempted closed reduction with immobilization, pathologic fracture mechanism, history of previous trauma or surgery to the affected bone, and fixation technique other than plate or K-wire. Results: We reviewed data for patients treated over a 22-year time period. Ultimately, 81 metacarpal shaft and neck fractures in 60 patients met inclusion criteria. Among all metacarpal fractures, complications were present in 39 (48.1%) cases. There were no significant associations between complication prevalence and hardware type. Revision surgery was required in 11 (13.6%) patients; there were no significant associations between revision procedures and hardware type. Postoperatively, all patients with imaging data had radiograph follow-up to assess union status. There was no significant association between time to union and hardware type. Conclusions: Outcomes showed no significant difference between plate and pin fixation for metacarpal shaft and neck fractures. These findings suggest that surgeons may have flexibility to decide on the type of operative intervention while considering patient-specific factors, such as the need for early mobilization.

Radiographic and Clinical Outcomes of Radioscapholunate Arthrodesis in Patients With Inflammatory and Posttraumatic Arthritis.

BACKGROUND: Radioscapholunate (RSL) fusion is performed for painful radiocarpal arthritis that is typically posttraumatic or inflammatory in nature. The purpose of this study was to determine whether patients with inflammatory conditions undergoing RSL fusion had comparable outcomes as those with posttraumatic arthritis and to determine factors impacting union. METHODS: This was a retrospective review of all RSL fusions over a 25-year period. Demographic information, wrist range of motion, postoperative complications, and surgical technique, including presence or absence of resection of distal scaphoid pole, data were collected. Radiographs were examined for evidence of healing of the RSL fusion site as well as development of midcarpal arthritis. RESULTS: Fifty-six patients underwent RSL fusion. Eight patients required revision of radiocarpal arthrodesis for painful nonunion. The fusion rate was 85.7%, and median 25th to 75th percentile (time to healing was 4.0 3.2-5.2) months. There were no differences in time to or rate of union by inflammatory arthropathy status. Grip strength increased significantly and pain decreased significantly with surgery. Union rate was 90% with the use of K-wires, screws, or staples, which was significantly greater than plates, fusion cups, or multiple implant types. The use of autologous bone graft significantly decreased the rate of nonunion and significantly decreased time to union by 3 months compared to allograft alone. Extension was significantly improved with scaphoid distal pole resection versus without distal scaphoid pole resection. CONCLUSIONS: Radioscapholunate (RSL) fusion is an effective treatment for radiocarpal arthritis but has high nonunion rates. Fixation with K-wires, screws, or staples and use of autograft confers improved union rate.

Effects of Negative Pressure Wound Therapy on Wound Dehiscence and Surgical Site Infection Following Instrumented Spinal Fusion Surgery-A Single Surgeon's Experience.

BACKGROUND: Incisional negative pressure wound therapy (NPWT) is used in many surgical specialties to prevent postoperative dehiscence and surgical site infections (SSIs). However, little is known about the role of incisional NPWT in spine fusion surgery. Therefore, we sought to report a single surgeon's experience using incisional NPWT and describe its effects on dehiscence and SSIs after instrumented spine surgery. METHODS: We compared rates of hospital readmission and return to the operating room for dehiscence and SSIs in a consecutive series of patients who underwent spinal fusion surgery with or without NPWT from 2015 to 2018. RESULTS: A total of 393 patients without and 76 patients with NPWT were included for analysis. Half way through the data collection period, all patients who underwent anterior lumbar fusion received NPWT. Three of 15 (20.0%) of non-NPWT patients who underwent anterior lumbar fusion had dehiscence or SSI compared with zero of 23 (0.0%) of NPWT patients (P = 0.01). NPWT for posterior surgeries was used on a case-by-case basis using risk factors that contribute to SSIs and dehiscence. NPWT patients had higher rates of spinal neoplasia (0.5% vs. 11.3%, P < 0.0001), osteomyelitis/diskitis (1.3% vs. 7.5%, P = 0.02), durotomy (14.9% vs. 28.6%, P = 0.007), revision surgery (32.2% vs. 59.6%, P = 0.0001), and longer fusion constructs (7 vs. 11 levels, P < 0.0001) but had similar rates of dehiscence and SSIs as non-NPWT patients (5.6% vs. 5.7%, P = 0.98). CONCLUSIONS: NPWT decreases dehiscence and SSIs in patients undergoing lumbar fusion through an anterior approach. When preferentially used in patients at high risk for postoperative wound complications, NPWT prevents increased rates of dehiscence and SSI.

Cost-effectiveness of dental antibiotic prophylaxis in total knee arthroplasty recipients with type II diabetes mellitus.

Objective: Type II diabetes mellitus (T2DM) is prevalent in knee osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA) and increases risk for prosthetic joint infection (PJI). We examined the cost-effectiveness of antibiotic prophylaxis (AP) before dental procedures to reduce PJI in TKA recipients with T2DM. Design: We used the Osteoarthritis Policy Model, a validated computer simulation of knee OA, to compare two strategies among TKA recipients with T2DM (mean age 68 years, mean BMI 35.4 kg/m2): 1) AP before dental procedures and 2) no AP. Outcomes included quality-adjusted life expectancy (QALE) and lifetime medical costs. We used published efficacy of AP. We report incremental cost-effectiveness ratios (ICERs) and considered strategies with ICERs below well-accepted willingness-to-pay (WTP) thresholds cost-effective. We conducted sensitivity analyses to examine the robustness of findings to uncertainty in model input parameters. We used a lifetime horizon and healthcare sector perspective. Results: We found that AP added 1.0 quality-adjusted life-year (QALY) and $66,000 for every 1000 TKA recipients with T2DM, resulting in an ICER of $66,000/QALY. In sensitivity analyses, reduction of the probability of PJI, T2DM-associated risk of infection, or attribution of infections to dental procedures by 50% resulted in ICERs exceeding $100,000/QALY. Probabilistic sensitivity analyses showed that AP was cost-effective in 32% and 58% of scenarios at WTP of $50,000/QALY and $100,000/QALY, respectively. Conclusions: AP prior to dental procedures is cost-effective for TKA recipients with T2DM. However, the cost-effectiveness of AP depends on the risk of PJI and efficacy of AP in this population.

Validation of the Fitbit Charge 2 compared to the ActiGraph GT3X+ in older adults with knee osteoarthritis in free-living conditions.

OBJECTIVE: To evaluate physical activity (PA) and sedentary time in subjects with knee osteoarthritis (OA) measured by the Fitbit Charge 2 (Fitbit) and a wrist-worn ActiGraph GT3X+ (AGW) compared to the hip-worn ActiGraph (AGH). DESIGN: We recruited a cohort of subjects with knee OA from rheumatology clinics. Subjects wore the AGH for four weeks, AGW for two weeks, and Fitbit for two weeks over a four-week study period. We collected accelerometer counts (ActiGraphs) and steps (ActiGraphs, Fitbit) and calculated time spent in sedentary, light, and moderate-to-vigorous activity. We used triaxial PA intensity count cut-points from the literature for ActiGraph and a stride length-based cadence algorithm to categorize Fitbit PA. We compared Fitbit wear times calculated from a step-based algorithm and a novel algorithm that incorporates steps and heart rate (HR). RESULTS: We enrolled 15 subjects (67% female, mean age 68 years). Relative to AGH, Fitbit, on average, overestimated steps by 39% and sedentary time by 37% and underestimated MVPA by 5 minutes. Relative to AGH, AGW overestimated steps 116%, underestimated sedentary time by 66%, and captured 281 additional MVPA minutes. The step-based wear time Fitbit algorithm captured 14% less wear time than the HR-based algorithm. CONCLUSIONS: Fitbit overestimates steps and underestimates MVPA in knee OA subjects. Cut-offs validated for AGW should be developed to support the use of AGW for PA assessment. The HR-based Fitbit algorithm captured more wear time than the step-based algorithm. These data provide critical insight for researchers planning to use commercially-available accelerometers in pragmatic studies.

Financial incentives for objectively-measured physical activity or weight loss in adults with chronic health conditions: A meta-analysis.

OBJECTIVE: We conducted a meta-analysis and systematic review of published randomized controlled trials (RCTs) to evaluate the impact of financial incentives (FI) on objectively-measured physical activity (PA) and weight loss (WL) in adults with sedentary behavior or chronic health conditions. EVIDENCE REVIEW: We performed a systematic search for RCTs published in English indexed in PubMed, Embase, or Web of Science through July 27, 2017. We limited our search to RCTs that involved an FI intervention with a monetary component, objectively-measured PA or WL outcomes, samples with either sedentary lifestyles or chronic health conditions, and a comparator group that did not receive performance-contingent FI. We calculated the mean difference and standardized mean difference (SMD) for each study and used a random effects model to summarize intervention efficacy. We used the Jadad scoring tool to assess the quality of the identified articles. RESULTS: We abstracted data from 11 RCTs. Two of the 11 included studies focused on PA, totaling 126 intervention and 116 control subjects. Nine RCTs evaluated the effect of FI on WL, totaling 1,799 intervention and 1,483 control subjects. The combined estimate for change in daily steps was 940 (95%CI [306-1,574]) more in PA intervention groups than in control groups and 2.36 (95%CI [1.80-2.93]) more kilograms lost by WL intervention groups compared to control groups. The overall estimated SMD for both outcomes combined was 0.395 (95%CI [0.243-0.546; p<0.001]), favoring FI interventions. CONCLUSION: FI interventions are efficacious in increasing PA and WL in adults with chronic conditions or sedentary adults. Public health programs to increase PA or prevent chronic disease should consider incorporating FI to improve outcomes.