Efficacy of ADIPOR1 and ADIPOR2 peptide-agonist AdipoRon in preventing contracture in a rabbit model of arthrofibrosis

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with potential antifibrotic effects. Whether AdipoRon can mitigate joint stiffness in a rabbit model of arthrofibrosis is unknown. We examined the efficacy of intravenous (IV) AdipoRon at mitigating contracture in a rabbit model of knee arthrofibrosis. Fifty-six female New Zealand White rabbits were divided into three dosing groups: vehicle (dimethyl sulfoxide, DMSO), 2.5 mg/kg AdipoRon, and 5 mg/kg AdipoRon. AdipoRon, in DMSO, was administered IV preoperatively and for 5 days postoperatively (30 rabbits, Aim 1). AdipoRon was again dosed similarly after Kirschner wire (K-wire) removal at 8 weeks (26 rabbits; Aim 2). The primary outcome of joint passive extension angle (PEA,°) was measured at 8, 10, 12, 16, and 24 weeks following index surgery. At 24 weeks, rabbits were euthanized and limbs were harvested to measure posterior capsular stiffness (N cm/°). In Aim 1, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 16-week (p < 0.05). In Aim 2, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 10-week (p < 0.05). In both aims, no significant differences were observed at later time points. Capsular stiffness was no different in any group. We are the first to report the efficacy of IV AdipoRon in a rabbit model of arthrofibrosis. We identified a significant dose-dependent decrease in joint PEA at early time points; however, no differences were observed between groups at later time points. Clinical Significance: The present investigation provided the first assessment of AdipoRon's efficacy in mitigating knee stiffness in the current gold standard rabbit model of arthrofibrosis. Results of this investigation provided further evidence as to the potential role of AdipoRon as a preventative for arthrofibrosis in large mammals.

The Effect of C2 Muscular Exposure Technique on Radiographic and Clinical Outcomes After C2-T2 Posterior Cervical Fusion

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications.

BACKGROUND

In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF.

PATIENTS AND METHODS

All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale-Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups.

RESULTS

A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P= 0.005) and more likely to have bone morphogenic protein (P< 0.001) and C2 pars screws (P= 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2-C3 segmental lordosis, C2-C3 listhesis, C0-C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2-C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups.

CONCLUSIONS

Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF.

LEVEL OF EVIDENCE

Level III.

The effect of C2 screw type on perioperative outcomes and long-term stability after C2-T2 posterior cervical decompression and fusion

PURPOSE

To determine if C2 pedicle versus pars screw type predicts change in fusion status, C2 screw loosening, cervical alignment, and patient-reported outcomes measures (PROMs) after C2-T2 posterior cervical decompression and fusion (PDCF).

METHODS

All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy between 2013-2020 were retrospectively identified. Patients were dichotomized by C2 screw type into bilateral C2 pedicle and bilateral C2 pars screw groups. Preoperative and short- and long-term postoperative radiographic outcomes and PROMs were collected. Univariate and multivariate analysis compared patient factors, fusion status, radiographic measures, and PROMs across groups.

RESULTS

A total of 159 patients met the inclusion/exclusion criteria (76 bilateral pedicle screws, 83 bilateral pars screws). Patients in the C2 pars relative to C2 pedicle screw group were on average more likely to have bone morphogenic protein (p = 0.001) and four-millimeter diameter rods utilized intraoperatively (p = 0.033). There were no significant differences in total construct and C2-3 fusion rate, C2 screw loosening, or complication and revision rates between C2 screw groups in univariate and regression analysis. Changes in C2 tilt, C2-3 segmental lordosis, C0-2 Cobb angle, proximal junctional kyphosis, atlanto-dens interval, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 screw type.

CONCLUSION

There were no significant differences in fusion status, hardware complications, and radiographic and clinical outcomes based on C2 screw type following C2-T2 PCDF. Accordingly, intraoperative usage criteria can be flexible based on patient vertebral artery positioning and surgeon comfort level.

Surgical Approach and Body Mass Index Impact Risk of Wound Complications Following Total Hip Arthroplasty

BACKGROUND

Previous studies have suggested that wound complications may differ by surgical approach after total hip arthroplasty (THA), with particular attention toward the direct anterior approach (DAA). However, there is a paucity of data documenting wound complication rates by surgical approach and the impact of concomitant patient factors, namely body mass index (BMI). This investigation sought to determine the rates of wound complications by surgical approach and identify BMI thresholds that portend differential risk.

METHODS

This multicenter study retrospectively evaluated all primary THA patients from 2010 to 2023. Patients were classified by skin incision as having a laterally based approach (posterior or lateral approach) or DAA (longitudinal incision). We identified 17,111 patients who had 11,585 laterally based (68%) and 5,526 (32%) DAA THAs. The mean age was 65 years (range, 18 to 100), 8,945 patients (52%) were women, and the mean BMI was 30 (range, 14 to 79). Logistic regression and cut-point analyses were performed to identify an optimal BMI cutoff, overall and by approach, with respect to the risk of wound complications at 90 days.

RESULTS

The 90-day risk of wound complications was higher in the DAA group versus the laterally based group, with an absolute risk of 3.6% versus 2.6% and a multivariable adjusted odds ratio of 1.5 (P < .001). Cut-point analyses demonstrated that the risk of wound complications increased steadily for both approaches, but most markedly above a BMI of 33.

CONCLUSIONS

Wound complications were higher after longitudinal incision DAA THA compared to laterally based approaches, with a 1% higher absolute risk and an adjusted odds ratio of 1.5. Furthermore, BMI was an independent risk factor for wound complications regardless of surgical approach, with an optimal cut-point BMI of 33 for both approaches. These data can be used by surgeons to help consider the risks and benefits of approach selection.

LEVEL OF EVIDENCE

Level III.

Periprosthetic Hip and Knee Infection: Is an Ipsilateral Uninfected Total Joint Arthroplasty at Risk?

BACKGROUND

Periprosthetic joint infections (PJIs) of total hip arthroplasty (THA) or total knee arthroplasty (TKA) may occur in the setting of an uninfected ipsilateral prosthetic joint. However, the risk to that uninfected ipsilateral joint is unknown. We analyzed the survivorship free from PJI in at risk THAs and TKAs following treatment of an ipsilateral knee or hip PJI, respectively.

METHODS

Using our institutional total joint registry, we identified 205 patients who underwent treatment for PJI (123 THAs and 83 TKAs) with an at-risk ipsilateral in situ knee or hip, respectively, between 2000 and 2019. In total, 54% of index PJIs were chronic and 46% were acute. The mean age was 70 years, 47% were female, and the mean body mass index was 32. Kaplan-Meier survivorship analyses were performed. Mean follow-up was 6 years.

RESULTS

The 5-year survivorship free of PJI in an at-risk THA after an ipsilateral TKA was treated for PJI was 97%. The 5-year survivorship free of PJI in an at-risk TKA when the ipsilateral THA was treated for PJI was 99%. Three PJIs occurred (2 THAs and 1 TKA), all over 1 year from the index ipsilateral PJI treatment. One hip PJI was an acute hematogenous infection that resulted from pneumonia. The other 2 new PJIs were caused by the same organism as the index PJI and were due to a failure of source control at the index joint.

CONCLUSIONS

When diagnosed with PJI in a single joint, the risk of developing PJI in an ipsilateral prosthetic joint within 5 years was low (1 to 3% risk). In the rare event of an ipsilateral infection, all occurred greater than one year from the index PJI and 2 of 3 were with the same organism when source infection control failed.

LEVEL OF EVIDENCE

Prognostic Level III.

The Chitranjan S. Ranawat Award: Manipulation Under Anesthesia to Treat Postoperative Stiffness After Total Knee Arthroplasty: A Multicenter Randomized Clinical Trial

BACKGROUND

Manipulation under anesthesia (MUA) occurs in 4% of patients after total knee arthroplasty (TKA). Anti-inflammatory medications may target arthrofibrosis pathogenesis, but the data are limited. This multicenter randomized clinical trial investigated the effect of adjuvant anti-inflammatory medications with MUA and physical therapy on range of motion (ROM) and outcomes.

METHODS

There were 124 patients (124 TKAs) who developed stiffness after primary TKA for osteoarthritis enrolled across 15 institutions. All received MUA when ROM was < 90° at 4 to 12 weeks postoperatively. Randomization proceeded via a permuted block design. Controls received MUA and physical therapy, while the treatment group also received one dose of pre-MUA intravenous dexamethasone (8 mg) and 14 days of oral celecoxib (200 mg). The ROM and clinical outcomes were assessed at 6 weeks and 1 year. This trial was registered with ClinicalTrials.gov.

RESULTS

The ROM significantly improved a mean of 46° from a pre-MUA ROM of 72 to 118° immediately after MUA (P < .001). The ROM was similar between the treatment and control groups at 6 weeks following MUA (101 versus 99°, respectively; P = .35) and at one year following MUA (108 versus 108°, respectively; P = .98). Clinical outcomes were similar at both end points.

CONCLUSIONS

In this multicenter randomized clinical trial, the addition of intravenous dexamethasone and a short course of oral celecoxib after MUA did not improve ROM or outcomes. However, MUA provided a mean ROM improvement of 46° immediately, 28° at 6 weeks, and 37° at 1 year. Further investigation in regards to dosing, duration, and route of administration of anti-inflammatory medications remains warranted.

LEVEL OF EVIDENCE

Level 1, RCT.

AdipoRon reduces TGFβ1-mediated collagen deposition in vitro and alleviates knee stiffness in vivo

Arthrofibrosis, which causes joint motion restrictions, is a common complication following total knee arthroplasty (TKA). Key features associated with arthrofibrosis include myofibroblast activation, knee stiffness, and excessive scar tissue formation. We previously demonstrated that adiponectin levels are suppressed within the knee tissues of patients affected by arthrofibrosis and showed that AdipoRon, an adiponectin receptor agonist, exhibited anti-fibrotic properties in human mesenchymal stem cells. In this study, the therapeutic potential of AdipoRon was evaluated on TGFβ1-mediated myofibroblast differentiation of primary human knee fibroblasts and in a mouse model of knee stiffness. Picrosirius red staining revealed that AdipoRon reduced TGFβ1-induced collagen deposition in primary knee fibroblasts derived from patients undergoing primary TKA and revision TKA for arthrofibrosis. AdipoRon also reduced mRNA and protein levels of ACTA2, a key myofibroblast marker. RNA-seq analysis corroborated the anti-myofibrogenic effects of AdipoRon. In our knee stiffness mouse model, 6 weeks of knee immobilization, to induce a knee contracture, in conjunction with daily vehicle (DMSO) or AdipoRon (1, 5, and 25 mg/kg) via intraperitoneal injections were well tolerated based on animal behavior and weight measurements. Biomechanical testing demonstrated that passive extension angles (PEAs) of experimental knees were similar between vehicle and AdipoRon treatment groups in mice evaluated immediately following immobilization. Interestingly, relative to vehicle-treated mice, 5 mg/kg AdipoRon therapy improved the PEA of the experimental knees in mice that underwent 4 weeks of knee remobilization following the immobilization and therapy. Together, these studies revealed that AdipoRon may be an effective therapeutic modality for arthrofibrosis.

Does Fracture Pattern Really Predict Displacement of LC1 Sacral Fractures?

BACKGROUND

Operative management of minimally displaced lateral compression type-1 (LC1) pelvic ring injuries remains controversial. We aimed to assess the proportion of LC1 pelvic fractures that displaced following nonoperative management as a function of specific ring fracture patterns, and we quantified the magnitude of this displacement.

METHODS

A retrospective review of the billing registry of a level-I trauma center was performed. Two hundred and seventy-three patients with a high-energy LC1 pelvic ring fracture and <5 mm of sacral displacement were included. The fracture pattern was characterized with use of computed tomography (CT) scans and radiographs. Absolute and interval pelvic ring displacement were quantified with use of previously described methodology.

RESULTS

Thirty-five pelvic ring injuries (13%) were displaced. The rate of displacement was 31% (15 of 49) for LC1 injuries involving a complete sacral fracture and bilateral ramus fractures, 12% (7 of 58) for injuries involving a complete sacral fracture and a unilateral ramus fracture, and 10% (5 of 52) for injuries involving an incomplete sacral fracture and bilateral ramus fractures. In displaced injuries, the average interval displacement was 4.2 mm (95% confidence interval [CI], 1.8 to 6.8) and the final displacement was 9.9 mm ± 4.2 mm.

CONCLUSIONS

Our study suggests that fracture characteristics can be used to predict the likelihood of displacement of LC1 fractures that are treated without surgery. To our knowledge, the present study is the first to describe the magnitude of displacement that may occur in association with LC1 pelvic ring injuries that are treated nonoperatively; however, further studies are needed to determine the clinical impact of this displacement.

LEVEL OF EVIDENCE

Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

A Standardized Curriculum Improves Trainee Rod Bending Proficiency in Spinal Deformity Surgery. Results of a Prospective Randomized Controlled Educational Study

INTRODUCTION

Surgical simulation is increasingly being accepted as a training platform to promote skill development and a safe surgical technique. Preliminary investigations in spine surgery show that simulation paired with educational intervention can markedly improve trainee performance. This study used a newly developed thoracolumbar fusion rod bending model to assess the effect of a novel educational curriculum and simulator training on surgical trainee rod bending speed and proficiency.

METHODS

Junior (PGY1 to 2) and senior (PGY3-fellow) surgical trainees at a single academic institution were prospectively enrolled in a rod bending simulation using a T7-pelvis spinal fusion model. Participants completed two simulations, with 1 month between first and second attempts. Fifty percent of surgeons in each training level were randomized to receive an educational curriculum (rod bending technique videos and unlimited simulator practice) between simulation attempts. Rod bending simulation proficiency was determined by the percentage of participants who completed the task (conclusion at 20 minutes), time to task completion or conclusion, and number of incomplete set screws at task conclusion. Participants completed a preparticipation and postparticipation survey. Univariate analysis compared rod bending proficiency and survey results between education and control cohorts.

RESULTS

Forty trainees (20 junior and 20 senior) were enrolled, with 20 participants randomized to the education and control cohorts. No notable differences were observed in the first simulation rod bending proficiency or preparticipation survey results between the education and control cohorts. In the second simulation, the education versus the control cohort demonstrated a significantly higher completion rate ( P = 0.01), shorter task time ( P = 0.009), fewer incomplete screws ( P = 0.003), and greater experience level ( P = 0.008) and comfort level ( P = 0.002) on postparticipation survey.

DISCUSSION

Trainees who participated in a novel educational curriculum and simulator training relative to the control cohort improved markedly in rod bending proficiency and comfort level. Rod bending simulation could be incorporated in existing residency and fellowship surgical skills curricula.

LEVEL OF EVIDENCE

I.

Irrigation and Debridement With Chronic Antibiotic Suppression for the Management of Acutely Infected Aseptic Revision Total Joint Arthroplasties

BACKGROUND

Most data on irrigation and debridement with component retention (IDCR) as a treatment for acute periprosthetic joint infections (PJIs) focuses on primary total joint arthroplasties (TJAs). However, the incidence of PJI is greater after revisions. We investigated the outcomes of IDCR with suppressive antibiotic therapy (SAT) following aseptic revision TJAs.

METHODS

Through our total joint registry, we identified 45 aseptic revision TJAs (33 hips, 12 knees) performed from 2000 to 2017 that were treated with IDCR for acute PJI. Acute hematogenous PJI was present in 56%. Sixty-four percent of PJIs involved Staphylococcus. All patients were treated with 4 to 6 weeks of intravenous antibiotics with the intention to treat with SAT (89% received SAT). The mean age was 71 years (range, 41 to 90), with 49% being women and a mean body mass index of 30 (range, 16 to 60). The mean follow-up was 7 years (range, 2 to 15).

RESULTS

The 5-year survivorships free from re-revision for infection and reoperation for infection were 80% and 70%, respectively. Of the 13 reoperations for infection, 46% involved the same species as the initial PJI. The 5-year survivorships free from any revision and any reoperation were 72% and 65%, respectively. The 5-year survivorship free from death was 65%.

CONCLUSION

At 5 years following IDCR, 80% of implants were free from re-revision for infection. As the penalty for implant removal is often high in revision TJAs, IDCR with SAT is a viable option for acute infection after revision TJAs in select patients.

LEVEL OF EVIDENCE

IV.

Health and Socioeconomic Risk Factors for Unplanned Hospitalization Following Ambulatory Unicompartmental Knee Arthroplasty: Development of a Patient Selection Tool Using Machine Learning

BACKGROUND

Identifying ambulatory surgical candidates at risk for adverse surgical outcomes can optimize outcomes. The purpose of this study was to develop and internally validate a machine learning (ML) algorithm to predict contributors to unexpected hospitalizations after ambulatory unicompartmental knee arthroplasty (UKA).

METHODS

A total of 2,521 patients undergoing UKA from 2006 to 2018 were retrospectively evaluated. Patients admitted overnight postoperatively were identified as those who had a length of stay ≥ 1 day were analyzed with four individual ML models (ie, random forest, extreme gradient boosting, adaptive boosting, and elastic net penalized logistic regression). An additional model was produced as a weighted ensemble of the four individual algorithms. Area under the receiver operating characteristics (AUROC) compared predictive capacity of these models to conventional logistic regression techniques.

RESULTS

Of the 2,521 patients identified, 103 (4.1%) required at least one overnight stay following ambulatory UKA. The ML ensemble model achieved the best performance based on discrimination assessed via internal validation (AUROC = 87.3), outperforming individual models and conventional logistic regression (AUROC = 81.9-85.7). The variables determined most important by the ensemble model were cumulative time in the operating room, utilization of general anesthesia, increasing age, and patient residency in more urban areas. The model was integrated into a web-based open-access application.

CONCLUSION

The ensemble gradient-boosted ML algorithm demonstrated the highest performance in identifying factors contributing to unexpected hospitalizations in patients receiving UKA. This tool allows physicians and healthcare systems to identify patients at a higher risk of needing inpatient care after UKA.

Identifying Modifiable Cost Drivers of Outpatient Unicompartmental Knee Arthroplasty With Machine Learning

BACKGROUND

Implementing tools that identify cost-saving opportunities for ambulatory orthopaedic surgeries can improve access to value-based care. We developed and internally validated a machine learning (ML) algorithm to predict cost drivers of total charges after ambulatory unicompartmental knee arthroplasty (UKA).

METHODS

We queried the New York State Ambulatory Surgery and Services database to identify patients who underwent ambulatory, defined as <24 hours of care before discharge, elective UKA between 2014 and 2016. A total of 1,311 patients were included. The median costs after ambulatory UKA were $14,710. Patient demographics and intraoperative parameters were entered into 4 candidate ML algorithms. The most predictive model was selected following internal validation of candidate models, with conventional linear regression as a benchmark. Global variable importance and partial dependence curves were constructed to determine the impact of each input parameter on total charges.

RESULTS

The gradient-boosted ensemble model outperformed all candidate algorithms and conventional linear regression. The major differential cost drivers of UKA identified (in decreasing order of magnitude) were increased operating room time, length of stay, use of regional and adjunctive periarticular analgesia, utilization of computer-assisted navigation, and routinely sending resected tissue to pathology.

CONCLUSION

We developed and internally validated a supervised ML algorithm that identified operating room time, length of stay, use of computer-assisted navigation, regional primary anesthesia, adjunct periarticular analgesia, and routine surgical pathology as essential cost drivers of UKA. Following external validation, this tool may enable surgeons and health insurance providers optimize the delivery of value-based care to patients receiving outpatient UKA.

LEVEL OF EVIDENCE

III.

Primary Total Hip Arthroplasty in Dialysis-Dependent Patients: 35% Mortality at 5 years

BACKGROUND

Limited knowledge exists on contemporary results of primary total hip arthroplasty (THA) in dialysis-dependent patients. We sought to analyze the mortality rates and cumulative incidences of any revision or reoperation in dialysis-dependent patients undergoing primary THAs.

METHODS

We identified 24 dialysis-dependent patients who underwent 28 primary THAs between 2000 and 2019 using our institutional total joint registry. Mean age was 57 years (range, 32 to 86), with 43% being women and mean body mass index was 31 (range, 20 to 50). The leading cause for dialysis was diabetic nephropathy (18%). The mean preoperative creatinine and glomerular filtration rate were 6 mg/dL and 13 mL/min, respectively. Kaplan-Meier survivorship methods and a competing risk analysis using death as the competing risk were performed. The mean follow-up was 7 years (range, 2 to 15).

RESULTS

The 5-year survivorship free from death was 65%. The 5-year cumulative incidence of any revision was 8%. There were a total of 3 revisions as follows: 2 for aseptic loosening of the femoral component and one for a Vancouver B2 fracture. The 5-year cumulative incidence of any reoperation was 19%. There were 3 additional reoperations, and all were irrigation and debridement. Postoperative creatinine and glomerular filtration rate were 6 mg/dL and 15 mL/min, respectively. At a mean of 2 years after THA, 25% successfully received a renal transplant.

CONCLUSIONS

Dialysis-dependent patients undergoing primary THAs had high 5-year mortality (35%) but an acceptably low cumulative incidence of any revision. While renal metrics remained consistent after THA, only one in 4 patients underwent successful renal transplant.

LEVEL OF EVIDENCE

IV.

Defining Clinically Meaningful Subgroups for Risk Stratification in Patients Undergoing Revision Total Hip Arthroplasty: A Combined Unsupervised and Supervised Machine Learning Approach

BACKGROUND

Studies developing predictive models from large datasets to risk-stratify patients under going revision total hip arthroplasties (rTHAs) are limited. We used machine learning (ML) to stratify patients undergoing rTHA into risk-based subgroups.

METHODS

We retrospectively identified 7,425 patients who underwent rTHA from a national database. An unsupervised random forest algorithm was used to partition patients into high-risk and low-risk strata based on similarities in rates of mortality, reoperation, and 25 other postoperative complications. A risk calculator was produced using a supervised ML algorithm to identify high-risk patients based on preoperative parameters.

RESULTS

There were 3,135 and 4,290 patients identified in the high-risk and low-risk subgroups, respectively. Each group significantly differed by rate of 30-day mortalities, unplanned reoperations/readmissions, routine discharges, and hospital lengths of stay (P < .05). An Extreme Gradient Boosting algorithm identified preoperative platelets < 200, hematocrit > 35 or < 20, increasing age, albumin < 3, international normalized ratio > 2, body mass index > 35, American Society of Anesthesia class ≥ 3, blood urea nitrogen > 50 or < 30, creatinine > 1.5, diagnosis of hypertension or coagulopathy, and revision for periprosthetic fracture and infection as predictors of high risk.

CONCLUSION

Clinically meaningful risk strata in patients undergoing rTHA were identified using an ML clustering approach. Preoperative labs, demographics, and surgical indications have the greatest impact on differentiating high versus low risk.

LEVEL OF EVIDENCE

III.

Femoral Head Length Impact on Outcomes Following Total Hip Arthroplasty in 36 Millimeter Cobalt Chrome-on-Highly Crosslinked Polyethylene Articulations

BACKGROUND

Despite concerns for corrosion, dislocation, and periprosthetic femur fractures, minimal literature has investigated the effect of adjusting femoral head length on outcomes after primary total hip arthroplasty (THA). Therefore, we aimed to investigate the effect of femoral head length on the risk of any revision and reoperation following cobalt chromium (CoCr)-on-highly crosslinked polyethylene (HXLPE) THAs.

METHODS

Between 2004 and 2018, we identified 1,187 primary THAs with CoCr-on-HXLPE articulations using our institutional total joint registry. The mean age at THA was 71 years (range, 19-97), 40% were women, and mean body mass index was 30 (range, 10-68). All THAs using 36 mm diameter femoral heads were included. Neutral (0 mm), positive, or negative femoral head lengths were used in 42, 31, and 27% of the THAs, respectively. Kaplan-Meier survivorship was assessed. The mean follow-up was 7 years (range, 2-16).

RESULTS

The 10-year survivorships free of any revision or reoperation were 94 and 92%, respectively. A total of 47 revisions were performed, including periprosthetic femur fracture (17), periprosthetic joint infection (8), dislocation (7), aseptic loosening of either component (6), corrosion (4), and other (5). Nonrevision reoperations included wound revision (11), open reduction and internal fixation of periprosthetic femur fracture (4), and abductor repair (2). Multivariable analyses found no significant associations between femoral head length and revision or reoperation.

CONCLUSION

Altering femoral head lengths in 36 mm CoCr-on-HXLPE THAs did not affect outcomes. Surgeons should select femoral head lengths that optimize hip stability and center of rotation.

LEVEL OF EVIDENCE

III.

Nonsteroidal Anti-Inflammatory Drugs and Oral Corticosteroids Mitigated the Risk of Arthrofibrosis After Total Knee Arthroplasty

BACKGROUND

The role of medications to prevent arthrofibrosis following total knee arthroplasty (TKA) remains unclear. We investigated the effect of common oral medications with reported antifibrotic properties on preventing arthrofibrosis and manipulation under anesthesia (MUA) following primary TKA.

METHODS

Using our total joint registry, 9,771 patients (12,735 knees) who underwent TKA with cemented, posterior-stabilized, and metal-backed tibial components from 2000 to 2016 were identified. Arthrofibrosis, defined as range of motion (ROM) ≤90° for ≥12 weeks postoperatively or as ROM ≤90° requiring MUA, was diagnosed in 454 knees (4%) and matched 1:2 to controls. Mean age was 62 years (range, 19 to 87) and 57% were women. The majority of operative diagnoses were osteoarthritis. Perioperative use of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins), angiotensin converting enzyme inhibitors (ACE inhibitors), angiotensin II receptor blockers (ARBs), oral corticosteroids, antihistamines, and nonsteroidal anti-inflammatory drugs (NSAIDs) were manually confirmed. Medication effect in preventing arthrofibrosis and MUA was assessed using adjusted multivariable analyses. Mean follow-up was 8 years (range, 2 to 20).

RESULTS

Reduced risk of arthrofibrosis was associated with perioperative NSAID use (odds ratio (OR) 0.67, P = .045). A similar trend was observed with perioperative corticosteroids (OR 0.52, P = .098). Corticosteroids were associated with reduced risk of MUA (OR 0.26, P = .036), and NSAIDs trended towards reducing MUA (OR 0.69, P = .11).

CONCLUSION

This investigation determined that perioperative NSAID use was associated with reduced risk of arthrofibrosis and trended towards reduced risk of subsequent MUA. Similarly, oral corticosteroids were associated with reduced risk of MUA and trended towards reduced risk of arthrofibrosis.

Performing 2-Stage Circumferential Fusion in an Adolescent With High-Grade Spondylolisthesis: A Surgical Technique

The surgical approach to high-grade spondylolisthesis at the lumbosacral junction remains controversial. Appropriate surgical techniques can be challenging with the potential for high complication rates, particularly with reduction. Multiple techniques have been described including posterior only reduction and instrumentation, posterior only instrumentation with in situ arthrodesis, and anterior-posterior reduction and instrumentation. Regardless of technique, the operative goals are to provide sufficient stability and biological support to promote bony fusion, maintain global balance, and decompress the neural elements while avoiding neurological complications. During instrumentation of a high-grade spondylolisthesis at the lumbosacral junction, it can be difficult to obtain access to the L5-S1 disc space for interbody insertion. We present a novel technique for improving access to the L5-S1 disc space through an osteotomy of the anterior-inferior aspect of the L5 vertebral body as part of a 2-stage circumferential fusion in the treatment of high-grade spondylolisthesis in an adolescent.

The Safety of Adiponectin Receptor Agonist AdipoRon in a Rabbit Model of Arthrofibrosis

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with numerous reported physiological benefits in murine models of human disease, including a proposed reduction in fibrosis. However, AdipoRon has never been investigated in rabbits, which provide a robust model for orthopedic conditions. We examined the safety of intravenous (IV) AdipoRon in New Zealand White (NZW) female rabbits surgically stressed by a procedure that mimics human arthrofibrosis. Fifteen female NZW rabbits were prospectively studied using increasing AdipoRon doses based on established literature. AdipoRon was dissolved in dimethyl sulfoxide (DMSO), diluted in normal saline, and administered IV preoperatively and for 5 subsequent days postoperatively. The primary outcome was overall toxicity to rabbits, whereas secondary outcomes were change in rabbit weights and hemodynamics and defining acid-base characteristics of the drug formulation. Two rabbits expired during preoperative drug administration at 25 mg/kg. Remaining rabbits received preoperative doses of DMSO (vehicle), 2.5, 5, or 10 mg/kg of AdipoRon without complications. On postoperative day 1, one rabbit sustained a tonic-clonic seizure after their second dose of 10 mg/kg AdipoRon. The remaining 12 rabbits (4 in each group) received six serial doses of vehicle, 2.5, or 5 mg/kg of AdipoRon without adverse effects. All formulations of AdipoRon were within safe physiological pH ranges (4-5). We are the first to report the use of IV AdipoRon in a surgically stressed rabbit model of orthopedic disease. AdipoRon doses of 5 mg/kg or less appear to be well-tolerated in female NZW rabbits. Impact statement We provided the first in vivo toxicity assessment and dose optimization of a new antifibrotic experimental medication, AdipoRon, in a surgically stressed rabbit model of knee arthrofibrosis.

Implementation of Machine Learning to Predict Cost of Care Associated with Ambulatory Single-Level Lumbar Decompression

BACKGROUND

With the emergence of the concept of value-based care, efficient resource allocation has become an increasingly prominent factor in surgical decision-making. Validated machine learning (ML) models for cost prediction in outpatient spine surgery are limited. As such, we developed and internally validated a supervised ML algorithm to reliably identify cost drivers associated with ambulatory single-level lumbar decompression surgery.

METHODS

A retrospective review of the New York State Ambulatory Surgical Database was performed to identify patients who underwent single-level lumbar decompression from 2014 to 2015. Patients with a length of stay of >0 were excluded. Using pre- and intraoperative parameters (features) derived from the New York State Ambulatory Surgical Database, an optimal supervised ML model was ultimately developed and internally validated after 5 candidate models were rigorously tested, trained, and compared for predictive performance related to total charges. The best performing model was then evaluated by testing its performance on identifying relationships between features of interest and cost prediction. Finally, the best performing algorithm was entered into an open-access web application.

RESULTS

A total of 8402 patients were included. The gradient-boosted ensemble model demonstrated the best performance assessed via internal validation. Major cost drivers included anesthesia type, operating room time, race, patient income and insurance status, community type, worker's compensation status, and comorbidity index.

CONCLUSIONS

The gradient-boosted ensemble model predicted total charges and associated cost drivers associated with ambulatory single-level lumbar decompression using a large, statewide database with excellent performance. External validation of this algorithm in future studies may guide practical application of this clinical tool.

A 92 protein inflammation panel performed on sonicate fluid differentiates periprosthetic joint infection from non-infectious causes of arthroplasty failure

Periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty, typically necessitating surgical intervention and prolonged antimicrobial therapy. Currently, there is no perfect assay for PJI diagnosis. Proteomic profiling of sonicate fluid has the potential to differentiate PJI from non-infectious arthroplasty failure (NIAF) and possibly clinical subsets of PJI and/or NIAF. In this study, 200 sonicate fluid samples, including 90 from subjects with NIAF (23 aseptic loosening, 35 instability, 10 stiffness, five osteolysis, and 17 other) and 110 from subjects with PJI (40 Staphylococcus aureus, 40 Staphylococcus epidermidis, 10 Staphylococcus lugdunensis, 10 Streptococcus agalactiae, and 10 Enterococcus faecalis) were analyzed by proximity extension assay using the 92 protein Inflammation Panel from Olink Proteomics. Thirty-seven of the 92 proteins examined, including CCL20, OSM, EN-RAGE, IL8, and IL6, were differentially expressed in PJI versus NIAF sonicate fluid samples, with none of the 92 proteins differentially expressed between staphylococcal versus non-staphylococcal PJI, nor between the different types of NIAF studied. IL-17A and CCL11 were differentially expressed between PJI caused by different bacterial species, with IL-17A detected at higher levels in S. aureus compared to S. epidermidis and S. lugdunensis PJI, and CCL11 detected at higher levels in S. epidermidis compared to S. aureus and S. agalactiae PJI. Receiver operative characteristic curve analysis identified individual proteins and combinations of proteins that could differentiate PJI from NIAF. Overall, proteomic profiling using this small protein panel was able to differentiate between PJI and NIAF sonicate samples and provide a better understanding of the immune response during arthroplasty failure.

Improved Sagittal Alignment Is Associated with Early Postoperative Neck Disability and Pain-Related Patient-Reported Outcomes Following Posterior Cervical Decompression and Fusion for Myelopathy

OBJECTIVE

To compare patient-reported outcomes measures (PROMs) following posterior cervical decompression and fusion (PCDF) based on changes in perioperative cervical sagittal alignment.

METHODS

We reviewed patients who underwent PCDF from C2 to T2 between the years 2015 and 2020. C2 sagittal vertical axis (SVA) and C2-C7 lordosis were assessed preoperatively and 1-year postoperatively. Neck Disability Index (NDI) and visual analog scale (VAS) Neck scores were collected preoperatively, 3 months' postoperatively, and 1-year postoperatively. PROMs were compared based on perioperative radiographic parameters.

RESULTS

Eighty-five patients were included in this study. Patients with preoperative C2 SVA <40 mm had a larger improvement in VAS Neck pain scores at 3 months' postoperatively (-4.9 vs. -3.0, P = 0.03) and a larger decrease in NDI scores at 1-year postoperatively (7.2 vs. 3.1, P = 0.04) than patients with C2 SVA ≥40 mm. Patients with postoperative C2 SVA <40 mm demonstrated lower VAS Neck pain scores at 3 months' postoperatively (2.0 vs. 3.4, P = 0.049). The cohort of patients with a decrease of C2 SVA by ≥5 mm demonstrated lower NDI at 3 months' postoperatively but not at 1-year postoperatively in comparison with patients whose C2 SVA increased or remained unchanged (11.7 vs. 23.8 vs. 18.2; P < 0.001). Patients in whom both C2 SVA and C2-C7 lordosis improved demonstrated superior NDI (P < 0.001) and VAS Neck (P = 0.007) at 3 months' but not at 1-year postoperatively.

CONCLUSIONS

In a uniform cohort of patients undergoing PCDF from C2 to T2, improvements in C2 SVA and C2-C7 lordosis were associated with improved early postoperative PROMs.

How Do Patients With Predominant Neck Pain Improve After Anterior Cervical Discectomy and Fusion for Cervical Radiculopathy?

BACKGROUND

The presence of predominant pain in the arm vs the neck as a predictor of postoperative outcomes after anterior cervical discectomy and fusion (ACDF) has been seldom reported; therefore, the purpose of this study was to determine whether patients with predominant neck pain improve after surgery compared to patients with predominant arm pain or those with mixed symptoms in patients undergoing ACDF for radiculopathy.

METHODS

A retrospective cohort study was conducted on patients who underwent ACDF at a single center from 2016 to 2018. Patients were split into groups based on preoperative neck and arm pain scores: neck (N) pain dominant group (visual analog scale [VAS] neck ≥ VAS arm by 1.0 point); neutral group (VAS neck < VAS arm by 1.0 point); or arm (A) pain dominant group (VAS arm ≥ VAS neck by 1.0 point), using a threshold difference of 1.0 point. Subsequently, individuals were substratified into 2 groups based on the arm to neck pain ratio (ANR): non-arm pain dominant defined as ANR ≤1.0 and arm pain dominant (APD) defined as ANR >1.0. Patient-reported outcome measurements including Neck Disability Index (NDI), Physical Component Score-12, and Mental Component Score (MCS-12) were compared between groups.

RESULTS

No significant differences between groups when stratifying patients using a threshold difference of 1.0 point. When stratifying patients using the ANR, those in the APD group had significantly higher postoperative MCS-12 (P = 0.008) and NDI (P = 0.011) scores. In addition, the APD group showed a greater magnitude of improvement for MCS-12 and NDI scores (P = 0.043 and P = 0.038, respectively). Multiple linear regression showed that the A and the APD groups were both independent predictors of improvement in NDI.

CONCLUSION

Patients with dominant arm pain showed significantly greater improvement in terms of MCS-12 and NDI scores compared to patients with dominant neck pain.

CLINICAL RELEVANCE

To compare the impact of ACDF on arm and neck pain in the context of cervical radiculopathy using patient-reported outcome measures as an objective measurement.

LEVEL OF EVIDENCE: 3

Radiographic evaluation of osteochondritis dissecans of the humeral capitellum: A systematic review

Background

The purpose of this study was to evaluate radiographic-based classification systems for osteochondritis dissecans (OCD) of the capitellum and determine their agreement with intraoperative findings.

Methods

Using PRISMA guidelines, we analyzed 44 studies utilizing a total of 19 classification systems.

Results

Magnetic resonance imaging (MRI)-based systems showed better predictive value of intraoperative staging, and the Itsubo and Kohyama classifications showed best predictive value for lesion stability.

Conclusions

No classification system effectively correlated with intraoperative findings. A combination of radiograph, MRI, and computed tomography will most accurately determine OCD lesion stability.

Level of evidence

IV, Systematic Review.

Predictors of Prolonged Opioid Use After Lumbar Fusion and the Effects of Opioid Use on Patient-Reported Outcome Measures

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To determine risk factors associated with prolonged opioid use after lumbar fusion and to elucidate the effect of opioid use on patient-reported outcome measures (PROMs) after surgery.

METHODS

Patients who underwent 1-3 level lumbar decompression and fusion with at least one-year follow-up were identified. Opioid data were collected through the Pennsylvania Prescription Drug Monitoring Program. Preoperative "chronic use" was defined as consumption of >90 days in the one-year before surgery. Postoperative "prolonged use" was defined as a filled prescription 90-days after surgery. PROMs included the following: Short Form-12 Health Survey PCS-12 and MCS-12, ODI, and VAS-Back and Leg scores. Logistic regression was performed to determine independent predictors for prolonged opioid use.

RESULTS

The final analysis included 260 patients. BMI >35 (OR: .44 [.20, .90], P = .03) and current smoking status (OR: 2.73 [1.14, 6.96], P = .03) significantly predicted postoperative opioid usage. Chronic opioid use before surgery was associated with greater improvements in MCS-12 (β= 5.26 [1.01, 9.56], P = .02). Patients with prolonged opioid use self-reported worse VAS-Back (3.4 vs 2.1, P = .003) and VAS-Leg (2.6 vs 1.2, P = .03) scores after surgery. Prolonged opioid use was associated with decreased improvement in VAS-Leg over time (β = .14 [.15, 1.85], P = .02).

CONCLUSIONS

Current smoking status and lower BMI were significantly predictive of prolonged opioid use. Excess opioid use before and after surgery significantly affected PROMs after lumbar fusion.

Intraoperative Fracture of a Dual Modular Delta Ceramic Femoral Head During Total Hip Arthroplasty: A Case Report

CASE

A 39-year-old man with cerebral palsy and hip dysplasia status post right Chiari osteotomy presented with right hip osteoarthritis in consultation for total hip arthroplasty (THA). During THA, a Delta ceramic head was misaligned on the taper, but this was obscured by an overlying dual modular polyethylene shell. When we attempted to tap the head onto the taper, fracture occurred requiring revision to a cobalt-chromium head due to slight taper damage.

CONCLUSION

To our knowledge, this is the first reported case of intraoperative fracture of a BIOLOX Delta dual modular head.

Genetic contributors to risk of schizophrenia in the presence of a 22q11.2 deletion

Schizophrenia occurs in about one in four individuals with 22q11.2 deletion syndrome (22q11.2DS). The aim of this International Brain and Behavior 22q11.2DS Consortium (IBBC) study was to identify genetic factors that contribute to schizophrenia, in addition to the ~20-fold increased risk conveyed by the 22q11.2 deletion. Using whole-genome sequencing data from 519 unrelated individuals with 22q11.2DS, we conducted genome-wide comparisons of common and rare variants between those with schizophrenia and those with no psychotic disorder at age ≥25 years. Available microarray data enabled direct comparison of polygenic risk for schizophrenia between 22q11.2DS and independent population samples with no 22q11.2 deletion, with and without schizophrenia (total n = 35,182). Polygenic risk for schizophrenia within 22q11.2DS was significantly greater for those with schizophrenia (padj = 6.73 × 10-6). Novel reciprocal case-control comparisons between the 22q11.2DS and population-based cohorts showed that polygenic risk score was significantly greater in individuals with psychotic illness, regardless of the presence of the 22q11.2 deletion. Within the 22q11.2DS cohort, results of gene-set analyses showed some support for rare variants affecting synaptic genes. No common or rare variants within the 22q11.2 deletion region were significantly associated with schizophrenia. These findings suggest that in addition to the deletion conferring a greatly increased risk to schizophrenia, the risk is higher when the 22q11.2 deletion and common polygenic risk factors that contribute to schizophrenia in the general population are both present.

Prevalence of femoro-acetabular impingement in non-arthritic patients with hip pain: a meta-analysis

PURPOSE

As the prevalence of femoro-acetabular impingement syndrome (FAIS) in symptomatic patients who lack evidence of hip osteoarthritis (OA) remains to be described, the purpose of this study was to calculate the prevalence of FAIS in this patient population.

METHODS

Libraries of PubMed, Embase, and Ovid were systematically reviewed for all studies between 2009 and 2019, investigating femoro-acetabular impingement and hip pain. Level I-IV studies delineating patients with hip pain who do not have OA (Tonnis or Outerbridge grades < three) were included. Demographics, outcomes, radiographic parameters, and criteria were entered into a meta-analysis to calculate the incidence of FAIS in non-arthritic symptomatic hips.

RESULTS

In total, 2264 patients (2758 hips) were included in the pooled analysis. Weighted mean age was 31 years. The incidence of FAIS in patients with no evidence of osteoarthritis but who complain of hip pain is 61% (47.3-74.4%). In total, 1483 hips were diagnosed with FAIS. Of the studies that described the rates of all three of the various subtypes of FAIS in their reports, 37% had a combined-type, 38% had a cam-type, and 25% had a pincer-type FAIS.

CONCLUSION

Femoroacetabular impingement should be suspected in 47 to 74% of patients with hip pain and without arthritis. Physicians must maintain a high index of suspicion for FAIS in young patients presenting with hip pain, as FAIS is a common and treatable condition that, if left alone, may lead to hip degeneration.

Intrasubstance Tear of the Short Head of Biceps With Musculocutaneous and Median Nerve Compression

Traumatic intrasubstance ruptures of the biceps brachii are rare. Injury to its tendinous insertion or origin is most common. Isolated short head injuries are rare, and musculocutaneous nerve involvement has been reported for these injuries. We present a unique case report of a young, healthy man who sustained a symptomatic median and musculocutaneous nerve compression resulting from an intrasubstance tear of the short head of the biceps after a snow blower injury. Short belly rupture with injury-associated scar tissue compression of both the median and musculocutaneous nerves was identified in the operating room. Microsurgical decompression and tendon repair with a modified Mason-Allen configuration using 0-Vicryl suture were done. By 11 months postoperative, the patient experienced resolution of his arm pain, extension and flexion improvement from 0 to +140 to +15 to +150, elimination of the Tinel sign and of concomitant arm deformity, and improvement of elbow strength.

Effects of Operating Room Size on Surgical Site Infection Following Lumbar Fusion Surgery

Background

Surgical site infections (SSIs) represent a devastating complication after spine surgery. Many factors have been identified, but the influence of operating room (OR) size on infection rate has not been assessed.

Methods

Two thousand five hundred and twenty-three patients who underwent open lumbar spine fusion at a single institution between 2010 and 2016 were included. Patients were dichotomized into large versus small groups based on OR volume. Bivariate logistic regression and a final multivariate model following a multicollinearity check were used to calculate odds of infection for all variables.

Results

A total of 63 patients (2.5%) developed SSIs with 46 (73%) in the larger OR group and 17 (27%) in the smaller OR group. The rate of SSIs in larger ORs was 3.02% compared with 1.81% in smaller ORs. Significant parameters impacting SSI in bivariate analysis included an earlier year of surgery, BMI > 30, more comorbidities, more levels decompressed and fused, smoking, and larger OR volumes. Multivariate analysis identified BMI > 30, Elixhauser scores, smoking, and increasing levels decompressed as significant predictors. Topical vancomycin was found to significantly decrease rate of infection in both analyses.

Conclusions

OR size (large versus small) was ultimately not a significant predictor of infection related to rates of SSIs, although it did show a clinical trend toward significance, suggesting association. Future prospective analysis is warranted.

Level of Evidence

3.

What is new with 22q? An update from the 22q and You Center at the Children's Hospital of Philadelphia

22q11.2 deletion syndrome (22q11.2DS) is a disorder caused by recurrent, chromosome-specific, low copy repeat (LCR)-mediated copy-number losses of chromosome 22q11. The Children's Hospital of Philadelphia has been involved in the clinical care of individuals with what is now known as 22q11.2DS since our initial report of the association with DiGeorge syndrome in 1982. We reviewed the medical records on our continuously growing longitudinal cohort of 1,421 patients with molecularly confirmed 22q11.2DS from 1992 to 2018. Most individuals are Caucasian and older than 8 years. The mean age at diagnosis was 3.9 years. The majority of patients (85%) had typical LCR22A-LCR22D deletions, and only 7% of these typical deletions were inherited from a parent harboring the deletion constitutionally. However, 6% of individuals harbored other nested deletions that would not be identified by traditional 22q11.2 FISH, thus requiring an orthogonal technology to diagnose. Major medical problems included immune dysfunction or allergies (77%), palatal abnormalities (67%), congenital heart disease (64%), gastrointestinal difficulties (65%), endocrine dysfunction (>50%), scoliosis (50%), renal anomalies (16%), and airway abnormalities. Median full-scale intelligence quotient was 76, with no significant difference between individuals with and without congenital heart disease or hypocalcemia. Characteristic dysmorphic facial features were present in most individuals, but dermatoglyphic patterns of our cohort are similar to normal controls. This is the largest longitudinal study of patients with 22q11.2DS, helping to further describe the condition and aid in diagnosis and management. Further surveillance will likely elucidate additional clinically relevant findings as they age.

Physiological Nocturnal Hand Swelling: A Prospective Evaluation of Healthy Volunteers

PURPOSE

The goal of this study was to quantify the variation in daily volume that is expected in the normal hand. Our hypothesis is that hand swelling occurs overnight.

METHODS

Hand volume measurements of 36 healthy volunteers with no hand pathology were taken daily at 8 am, 2 pm, and 8 pm over a 3-day period. Participants were blinded to the objective of the study. Statistical analysis was performed to determine if any of the time points or patient demographics were associated with an increased change in hand volume.

RESULTS

Thirty-six healthy volunteers with mean age of 40.9 years and mean body mass index of 24.2 kg/m² were enrolled. Twenty-one volunteers were men and 15 were women. Three of the volunteers were left-handed. The key finding from this study was that the change in hand volume overnight (8 pm-8 am) is significantly different than the change in hand volume from 8 am to 2 pm and from 2 pm to 8 pm. Although there was a significant reduction in hand volume from 8 am to 2 pm, the further reduction in hand volume from 2 pm to 8 pm was not significant after correcting for the number of post hoc comparisons. In addition, demographic variables such as age, body mass index, and sex did not influence changes in hand volume.

CONCLUSIONS

Physiological hand swelling occurs overnight in individuals without active or prior hand pathology. Hand volume then decreases over the course of the day in these same individuals.

CLINICAL RELEVANCE

By investigating the changes in hand volume that occur overnight and throughout the day, we gain a better understanding of the temporal relationship between hand swelling and symptoms of chronic hand disease.