HSS Journal®: The Musculoskeletal Journal of Hospital for Special Surgery

The body-composition-modifying effects of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) remain incompletely characterized, particularly by direct measures of skeletal muscle beyond dual-energy X-ray absorptiometry. This knowledge gap puts vulnerable populations at risk.

We sought to answer the following question: Is GLP-1 RA use associated with changes in muscle quality as defined by total muscle area, functional cross-sectional area (fCSA), and fatty infiltration (FI), and measured by serial magnetic resonance imaging (MRIs) in the paraspinal musculature of diabetic patients with low back pain?

We conducted a single-center, retrospective cohort study including patients with diabetes and low back pain with at least 2 imaging studies taken at least 3 months apart between 2014 and 2024. Total muscle area, fCSA, and FI were calculated for each patient in the bilateral psoas and posterior paraspinal muscles on T2-weighted axial MRIs. Normalized muscle change per year was calculated between scans for each patient (the difference between muscle measurement on the most recent and the baseline MRI, divided by the length of follow-up). Multivariable linear regression models adjusted for age, baseline body mass index, and sex examined the association of GLP-1 use and muscle changes per year.

We examined data on 38 patients on a GLP-1 RA (61% male, median age 67 years) and 128 patients on any other diabetes medication (54% male, median age 71 years). The average duration of treatment for the GLP-1 RA cohort was 21.7 ± 10.7 months, with baseline imaging predating treatment by an average of 10.4 ± 10.1 months. We observed no significant longitudinal differences in estimates of FI or fCSA in the psoas, erector spinae, or multifidus in GLP-1 users compared to controls.

This retrospective single-institution study observed no statistically significant differences in changes in paraspinal muscle quality in patients with diabetes and low back pain taking a GLP-1 RA compared to controls. However, this preliminary study may have been underpowered to detect small to moderate effects. Further adequately powered, long-term studies are essential to establish the effects of GLP-1 RAs on muscle quality, especially research using standardized imaging metrics of body composition and muscle quality.

Level III, retrospective cohort study.

Diabetes is a well-established risk factor for a multitude of adverse outcomes in total knee arthroplasty (TKA). However, the effects of prediabetes (hemoglobin A1c 5.7%-6.4%) on TKA patient outcomes have yet to be fully elucidated.

We sought to compare inpatient rates of postoperative complications and resource use in patients with and without prediabetes undergoing primary, elective TKA.

We performed a retrospective cohort study using data from the Nationwide Inpatient Sample to identify patients with and without prediabetes undergoing unilateral, primary, elective TKA from January 1, 2017 to December 31, 2020. Patients with prediabetes were matched 1:1 to patients without prediabetes. There were 65 330 patients identified and included, with half in each cohort.

For patients undergoing TKA, having prediabetes was associated with higher rates of respiratory failure (0.4% vs 0.3%), aspiration pneumonitis (0.05% vs 0.02%), postoperative urinary retention (2.4% vs 2.0%), postoperative constipation (3.7% vs 2.8%), postoperative nausea and vomiting (3.3% vs 3.0%), postoperative anemia (15.0% vs 12.9%), hypotension (3.1% vs 2.2%), wound dehiscence (0.03% vs 0.00%), and infection (0.11% vs 0.05%) compared to patients without prediabetes. Having prediabetes was associated with increased total costs ($17 197 vs $15 544).

This retrospective cohort study found that in TKA patients, prediabetes was associated with higher rates of postoperative complications and increased costs compared to patients without prediabetes.

Level III: retrospective cohort study.

As the demand for total shoulder arthroplasty (TSA) increases, it is imperative to optimize preoperative risk factors. While glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are used for glycemic control or weight management in patients with obesity or diabetes, the impact of preoperative use on postoperative TSA outcomes in non-obese patients is unknown.

We sought to answer the question: Does preoperative use of GLP-1 RAs lead to increased risk of medical or surgical complications after TSA?

We conducted a retrospective cohort study using data from the TriNetX Network to analyze non-obese patients (BMI <30 kg/m²) who underwent anatomic or reverse shoulder arthroplasty between 2013 (the inception of the network) and January 2024 and had at least 1 year of follow up. Patients were categorized by preoperative GLP-1 RA use and matched 1:1 using propensity scores to balance the cohorts based on demographic variables and comorbidities. Outcomes assessed at 90 days and 1 year included revision surgery, emergency department visits, readmission, venous thromboembolism, pulmonary embolism, acute kidney injury, prosthetic joint stiffness, postoperative rotator cuff tear, dislocation, periprosthetic fracture or joint infection, surgical site infection, aspiration, cardiac arrest, and blood transfusion.

Among 108 352 non-obese patients, 845 used GLP-1 RAs preoperatively. After propensity score matching, 845 patients remained in each cohort with no significant baseline differences. In the 90 day postoperative period, there were no significant differences in any medical complications between the GLP-1 RA and control groups. Similarly, at 1 year, there were no significant differences in any medical or surgical complications between groups.

This retrospective cohort study found that preoperative GLP-1 RA use in non-obese TSA patients was not associated with an increased rate of major postoperative medical or surgical complications.

Level III: retrospective cohort study.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may reduce surgical risks through metabolic and anti-inflammatory benefits, but their evidence in spine surgery remains mixed.

We sought to compare postoperative outcomes and healthcare use after lumbar discectomy between GLP-1 RA users and 2 control cohorts: obese and normal body mass index (BMI) patients.

Adults with lumbar disk herniation undergoing single-level discectomy (2010-2023) were identified in the PearlDiver database. Three cohorts were created: (1) GLP-1 RA users (N = 540); (2) obese controls (N = 63 445); and (3) normal-BMI controls (N = 96,965). After propensity score matching (PSM), 539 GLP-1 RA users were matched with 539 obese controls on age, sex, Charlson Comorbidity Index (CCI), diabetes mellitus, and tobacco use. Two-tailed t-tests and χ² tests were performed for pairwise comparisons between unmatched and matched GLP-1 RA users and obese controls.

Compared to obese controls, GLP-1 RA users demonstrated lower rates of 90-day medical complications, such as pneumonia, that persisted after PSM, and lower rates of 90-day emergency department visits before and after PSM. In addition, GLP-1 RA users demonstrated lower rates of hospital readmissions compared to obese controls, before and after PSM. GLP-1 RA users incurred higher total 90-day costs, but this did not persist after PSM. While GLP-1 RA users had higher 2-year revision discectomy rates than matched obese controls (4.1% vs 2.4%), this difference was not statistically significant.

After PSM on demographics and select comorbidities, preoperative GLP-1 RA exposure was associated with lower 90-day medical complications, unplanned ED visits, and readmissions following single-level lumbar discectomy compared to obese controls. Revision discectomy and lumbar fusion rates were not significantly different after matching. Future research is needed to guide perioperative management of GLP-1 RA medications.

Level III, Retrospective comparative cohort study

Total hip arthroplasty (THA) continues to shift from inpatient to outpatient facilities.

We sought to examine trends in THA settings, demographic differences, and comorbidity variations to inform patient selection, outcomes, and policy.

We performed a retrospective study using data from January 1, 2019, to December 31, 2022, which we obtained from the Nationwide Inpatient Sample database and Nationwide Ambulatory Surgery Sample, from the U.S. Agency for Healthcare Research and Quality. Patients undergoing primary, elective THA were identified.

Of the 1 449 639 patients we identified who underwent elective THA, 843 824 underwent the procedure in a hospital-owned ambulatory facility and 605 815 in a hospital (inpatient setting). A total of 86% of THA volume migrated to outpatient centers from 2019 to 2022. Patients who underwent THA at an outpatient facility versus an inpatient setting were younger (65.3 vs 66.3 years). A higher percentage of female versus male patients had surgery in a hospital than in an outpatient center (56.2% vs 53.8%). White and black patients were more likely to be treated at an inpatient facility, whereas Hispanic patients were more likely to be treated at an outpatient facility. Medicare and Medicaid patients were more likely to undergo surgery as inpatients. Patients with medical comorbidities, as well as smokers and patients with opioid use disorder, were overwhelmingly more likely to undergo inpatient THA.

This retrospective database analysis found that from 2019 through 2022, outpatient THA numbers increased each year, with 90% of THAs being performed in hospital-owned ambulatory facilities in 2022. Patients with significant medical comorbidities and Medicare/Medicaid insurance, as well as white and black patients, were more likely to have inpatient surgery.

Level III, Retrospective Database Study.

Basicervical (BC) hip fractures represent a unique proximal femur fracture pattern for which the optimal treatment approach remains uncertain.

We sought to evaluate demographic, perioperative, and outcome differences among patients with BC (31B3), intertrochanteric (IT; 31A1.2), and valgus femoral neck (VFN; 31B1.1) fractures treated with internal fixation.

We conducted a retrospective review using prospectively collected data from October 2014 to March 2025 from a hip fracture database comprising 2 urban trauma centers. Patients with AO/OTA-classified 31B3, 31A1.2, or 31B1.1 fractures treated with non-arthroplasty fixation were included. Demographics, comorbidities, fracture characteristics, surgical constructs, and short- and long-term outcomes were compared. Multivariate regressions adjusted for baseline health and procedure type.

Of the 875 patients who met inclusion criteria, 122 had BC fractures, 523 had IT fractures, and 230 had VFN fractures. Patients with BC fractures were significantly younger than those with IT fractures; they had higher American Society of Anaesthesiologist scores and a greater proportion of household ambulators compared to those with VFN fractures, but were otherwise similar in comorbidity status. The BC cohort had significantly more minor in-hospital complications compared to the VFN cohort, even after multivariate adjustment. No significant differences were observed in 30-day mortality or major complications. Long-term outcomes were comparable across all groups. No significant differences in short- or long-term outcomes were observed across surgical constructs within the BC cohort.

Despite differing in baseline health status and surgical fixation strategies, BC fractures demonstrated comparable long-term outcomes to IT and VFN fractures. However, higher rates of minor complications in the BC group, even after adjustment, highlight a potentially greater perioperative risk. These findings suggest that while fixation may be effective long-term, further research is warranted to optimize acute management strategies for this anatomically and clinically distinct fracture pattern.

Level IV: Prognostic retrospective study

Interest in robotic-assisted total hip arthroplasty (RA-THA) continues to grow, despite inconsistent evidence on its effectiveness.

We sought to assess for the presence of spin bias in abstracts of systematic reviews and meta-analyses (SRMAs) comparing RA-THA to conventional total hip arthroplasty (C-THA).

We conducted a systematic review of studies identified in a comprehensive search of MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews from each database’s inception to June 23, 2025. Search terms included “robotic,” “hip,” “arthroplasty,” “systematic review,” and “meta-analysis.” Inclusion criteria were (1) SRMAs evaluating outcomes of RA-THA, (2) studies comparing RA-THA to conventional techniques, and (3) publications in English. Studies were excluded if they (1) assessed RA-THA with other robotic-assisted joint arthroplasty procedure, or (2) assessed RA-THA surgery alongside other technologies. Abstracts were assessed for the 15 most severe forms of spin as defined by Yavchitz et al. Methodological quality was assessed using the AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews-2) tool.

Twelve SRMAs were eligible for inclusion. Eleven SRMAs (91.7%) contained at least 1 of the 15 most severe forms of spin. Type 3 spin (selective reporting of efficacy outcomes favoring the intervention) was the most common (58%), followed by type 5 (conclusion claims the beneficial effect of the experimental intervention despite high risk of bias in primary studies; 50%), and type 11 (conclusion focuses selectively on statistically significant efficacy outcome; 33.3%). No differences in study characteristics were found between SRMAs with and without the aforementioned types of spin. All SRMAs were rated as “critically low” in methodological quality, with most not reporting funding source of included studies (91.7%).

This systematic review found there is a high prevalence of spin bias in abstracts of SRMAs evaluating RA-THA. The most common type of spin involved selective reporting of outcomes favoring RA-THA (type 3). Future SRMAs can minimize spin by presenting balanced reporting of efficacy, or lack thereof, in their abstracts and strengthen methodological rigor by consistently reporting study funding sources.

Level IV, Systematic review of level-I to level-IV studies.

Primary spine/pelvic tumors are aggressive, and en bloc resection is often essential. While stereotactic navigation is increasingly used for instrumentation in spine surgery, its specific role in tumor resection remains incompletely defined.

We sought to describe (1) reported rates of achieving negative margins, (2) local recurrence, (3) complications attributed to navigation, and (4) comparative outcomes from studies involving nonnavigated controls.

We conducted a systematic review according to preferred reporting items for systematic reviews and meta-analysis guidelines. Databases were queried for studies investigating the use of stereotactic navigation in primary spine/pelvic tumor surgery. Outcomes including surgical margin status, local recurrence, and complications were extracted and qualitatively synthesized using a best-evidence approach.

Twenty-one studies with 240 patients were included. The mean patient age was 46 years with follow-up of 33.4 months. Tumors were most often located in the sacrum/pelvis (81.3%), followed by the thoracic (8.3%), cervical (5.8%), and lumbar spine (4.6%). Chordoma (31.7%) and chondrosarcoma (27.1%) were the most frequently reported types. Negative surgical margins were achieved in 88.3% of cases. Local recurrence was reported in 16% of patients, with the highest observed in chondrosarcoma (32.4%). Complications occurred in 30.3% of patients; however, only 1% (2 cases) were attributed to navigation use. Two comparative studies examining navigated versus nonnavigated cohorts suggested improved bony margins and lower recurrence risk with navigation.

Early studies suggest that stereotactic navigation may be a feasible and safe adjunct for the resection of primary spine/pelvic tumors, particularly in achieving adequate bony margins. However, the current evidence is limited to small retrospective studies with heterogeneity in methodology, tumor type, and follow-up.

Level IV: Systematic review of level-III and level-IV studies.