JBJS

Quantifying Changes in 3D Acetabular Morphology in Normal Hips Based on the Development of Secondary Ossification Centers

J Bone Joint Surg Am. 2025 Sep 12. doi: 10.2106/JBJS.25.00428. Online ahead of print.

ABSTRACT

BACKGROUND: Acetabular development in pediatric hips is driven by growth from the triradiate cartilage (TRC) and secondary ossification centers (SOCs) of the os pubis, os ischium, and os ilium. These SOCs appear and fuse at different ages, with sex-specific differences affecting their morphology. This study quantifies the impact of SOCs on acetabular coverage, version, tilt, and surface area during adolescence.

METHODS: Three-dimensional (3D) surface reconstructions of 540 normal hips (in 128 male and 142 female patients) aged 8 to 19 years with no hip pathology were generated from computed tomography (CT) scans. Acetabular parameters, including coverage angles in predefined octants, version, tilt, and surface area, were extracted with use of a previously published algorithm. The Proximal Femur Maturity Index (PFMI) was used to assess skeletal maturity. Contributions to acetabular morphology from the 3 SOCs were analyzed using generalized linear mixed models. Significance was defined as p < 0.05.

RESULTS: PFMI grades strongly correlated with chronological age (rs = 0.91; p < 0.001). Os ilium ossification was significantly associated with increased superior coverage (p < 0.001), and os ischium ossification was associated with increased posterior coverage (p < 0.001). Superior coverage demonstrated a strong correlation with lateral tilt (rs = 0.837; p < 0.001), and posterior coverage was strongly correlated with anteversion (rs = 0.788; p < 0.001). Female patients exhibited greater acetabular anteversion (17.7° ± 6.4° versus 12.2° ± 6.4°; p < 0.001) and lateral tilt (38.5° ± 4.7° versus 36.6° ± 5.7°; p < 0.001), whereas male patients demonstrated larger acetabular surface area (31.9 ± 6.4 versus 28.8 ± 4.2 cm2; p < 0.001). We did not find a significant association between os pubis ossification and increased anterior coverage in male (p = 0.38) or female (p = 0.065) patients, nor did we find a correlation between anterior coverage and age (p = 0.115).

CONCLUSIONS: Os ilium and os ischium ossification were associated with increased superior and posterior acetabular coverage, respectively, during adolescence. In contrast, os pubis ossification was not associated with changes in anterior coverage. The timing of SOC appearance and closure aligns with key developmental changes in acetabular morphology, reinforcing the role of SOCs in determining hip stability.

LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

PMID:40939009 | DOI:10.2106/JBJS.25.00428

Modern Alignment Strategies in Total Knee Arthroplasty and How to Best Achieve Them

J Bone Joint Surg Am. 2025 Sep 12. doi: 10.2106/JBJS.25.00480. Online ahead of print.

ABSTRACT

➢ Adherence to accepted definitions of the various alternative total knee arthroplasty alignment strategies is important for research and communication between surgeons.➢ Technological advances, including robotics and navigation-assisted systems, have made precise execution of alternative alignment strategies feasible.➢ Modern studies have suggested that minor deviations (±3°) from neutral mechanical alignment do not significantly impact long-term total knee arthroplasty implant survivorship.➢ Individualized alignment strategies, such as kinematic, restricted kinematic, and functional alignment, aim to respect native anatomy and soft-tissue balance.➢ The majority of studies comparing intermediate-term outcomes of kinematic and mechanical alignment suggest noninferior outcomes with kinematic alignment; however, some studies have suggested superior outcomes with kinematic alignment.

PMID:40938970 | DOI:10.2106/JBJS.25.00480

The Broken Wing Sign: A New Clinical Test to Detect Gluteus Medius Pathology with and without Fatty Infiltration

J Bone Joint Surg Am. 2025 Sep 12. doi: 10.2106/JBJS.25.00427. Online ahead of print.

ABSTRACT

BACKGROUND: Gluteus medius tears and atrophy cause lateral hip pain, limp, and functional impairment. We developed the "broken wing sign," a novel physical examination test for detecting gluteus medius tendon tears and muscle degeneration. This study evaluated its diagnostic accuracy and clinical utility against magnetic resonance imaging (MRI) and intraoperative findings.

METHODS: We prospectively examined 59 patients (75 hips; mean age, 69.5 ± 10.8 years; 48 women) with suspected hip abductor insufficiency. The broken wing sign was tested with patients prone, the knee flexed at 90°, and the hip actively extended. A positive sign involved ≥10° of compensatory external hip rotation, visible as an inward drift of the foot, indicating gluteus medius (and resulting internal rotation) weakness. MRI served as the reference standard for classifying gluteus medius integrity as no tear, partial, full-thickness, or massive. Fatty infiltration was graded (Goutallier grades 0 to 4), quantified, and analyzed for a correlation with the examination findings. Diagnostic accuracy metrics were calculated.

RESULTS: The broken wing sign demonstrated high accuracy (sensitivity, 81.8%; specificity, 80.0%; positive predictive value [PPV], 91.8%; negative predictive value, 61.5%; diagnostic odds ratio, 17.8). An external rotation threshold of ≥30° yielded 100% specificity and 100% PPV for a tear. The sign detected acute tears with no or minimal fatty infiltration (100% sensitivity for massive tears). The degree of the external rotation angle was strongly correlated with muscle atrophy with fatty infiltration, showing 88.0% sensitivity for Goutallier grade ≥3 and 100% sensitivity for grade 4.

CONCLUSIONS: The broken wing sign is clinically useful for diagnosing gluteus medius tendon tears and muscle atrophy, particularly massive tears and advanced fatty degeneration. It effectively guides MRI utilization and surgical planning, serving as a valuable initial diagnostic tool in the clinical setting.

LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

PMID:40938961 | DOI:10.2106/JBJS.25.00427

Hip and Knee Arthroplasty in Patients with Obesity

J Bone Joint Surg Am. 2025 Sep 12. doi: 10.2106/JBJS.25.00131. Online ahead of print.

ABSTRACT

➢ Obesity is associated with increased postoperative complications and reoperation following total joint arthroplasty.➢ Meaningful functional improvement can be achieved with appropriate measures.➢ Preoperative measures include medical optimization, weight management, and consideration of bariatric surgery and glucagon-like peptide-1 receptor agonists.➢ Perioperative optimization requires an experienced multidisciplinary team and awareness of technical considerations for patients with obesity undergoing total joint arthroplasty.

PMID:40938955 | DOI:10.2106/JBJS.25.00131

Congenital Cervical Scoliosis at the Craniovertebral Junction: Clinical Characteristics and Surgical Strategies in 27 Patients with Mid-Term Follow-up

J Bone Joint Surg Am. 2025 Sep 11. doi: 10.2106/JBJS.24.01233. Online ahead of print.

ABSTRACT

BACKGROUND: Congenital cervical scoliosis at the craniovertebral junction is an exceedingly rare condition, with limited existing research. In this study, we aimed to elucidate the clinical characteristics, surgical strategies, and postoperative outcomes associated with this unique pathology, providing a comprehensive analysis to enhance clinical understanding and management.

METHODS: We conducted a retrospective analysis involving 27 patients with congenital cervical scoliosis at the craniovertebral junction who underwent surgery at a mean age of 7.81 ± 1.52 years. The median follow-up duration was 36.00 months. Patients were categorized into Group A and Group B on the basis of the absence or presence of concomitant subaxial cervical scoliosis, respectively. Three distinct surgical strategies were employed accordingly. Radiographic parameters were measured preoperatively, within 5 days postoperatively, and at the final follow-up. Other clinical and surgical characteristics were also collected.

RESULTS: Patients exhibited preoperative coronal imbalance, with a mean structural Cobb angle of 30.75° ± 13.09° and a mean head shift of 20.34 ± 13.23 mm. At the final follow-up, these parameters had significantly improved to a median of 3.00° and 8.59 mm (both p < 0.05). The mean operative time was 473.74 ± 134.29 minutes, and the mean intraoperative blood loss was 336.11 ± 166.52 mL. Among the 27 patients, 10 were in Group A and the other 17 were in Group B. Twenty-three patients/families reported being "satisfied" or "very satisfied" with the surgical outcome at the final follow-up. Postoperative complications occurred in 11 patients; no nerve root or vertebral artery injuries were observed.

CONCLUSIONS: Congenital cervical scoliosis at the craniovertebral junction is a complex deformity that severely influences coronal alignment. Nevertheless, tailored surgical strategies have shown promising effectiveness in achieving satisfactory clinical and psychological results.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

PMID:40934292 | DOI:10.2106/JBJS.24.01233

Prophylaxis Against Complex Regional Pain Syndrome Recurrence with Vitamin C in Total Knee Arthroplasty: A Propensity Score-Matched Analysis of 960 Cases

J Bone Joint Surg Am. 2025 Sep 9. doi: 10.2106/JBJS.24.01584. Online ahead of print.

ABSTRACT

BACKGROUND: Several studies have investigated the risk of complex regional pain syndrome (CRPS) and its prevention with vitamin C. However, evidence regarding the effectiveness of vitamin C for prevention of CRPS development or recurrence after total knee arthroplasty (TKA) is lacking.

METHODS: This retrospective single-center observational cohort study, which utilized propensity-score matching (PSM), was conducted from January 2017 to December 2021. It initially included 1,088 TKAs, 49 of which were in patients who had a previous CRPS. After exclusion of 50 TKAs, the study included 467 TKAs (45%) in patients who received vitamin C prophylaxis (1 g daily for 40 days) after surgery and 571 (55%) in patients who did not. After 1:1 matching on the basis of sex, age, body mass index, presence of diabetes mellitus and hypertension, use of tobacco and alcohol, anesthesia modality, tourniquet use, and anxiety and depression, the vitamin C group and the no-vitamin C group comprised 480 patients each. Twenty-eight of these 960 patients had a history of CRPS.

RESULTS: In the PSM population, 6.9% (33) of the 480 patients who received vitamin C prophylaxis after TKA developed CRPS compared with 11.0% (53) of the 480 who did not receive vitamin C (odds ratio [OR] = 0.59 [95% confidence interval (CI), 0.37 to 0.9], p = 0.024). The rate of CRPS was significantly higher in patients with a history of CRPS (32% versus 8% for patients with no previous CRPS; OR = 5.4 [95% CI, 2.57 to 11.4], p < 0.001). In the 28 patients with a history of CRPS, vitamin C prophylaxis reduced the rate of CRPS recurrence after TKA to 19% (4 of 21) compared with 71% (5 of 7) in the patients not treated with vitamin C (OR = 0.09 [95% CI, 0.01 to 0.64], p = 0.02). In multivariable regression of the matched patients, vitamin C was also found to be independently associated with a lower rate of CRPS recurrence after TKA (OR = 0.53 [95% CI, 0.3 to 0.86], p = 0.011).

CONCLUSIONS: Vitamin C prophylaxis may be appropriate for preventing CRPS after TKA. Furthermore, the study highlights the beneficial role of vitamin C in reducing the rate of CRPS recurrence in patients with a history of CRPS who are undergoing TKA.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

PMID:40924823 | DOI:10.2106/JBJS.24.01584

Principles of Level Selection for Instrumentation in Adult Thoracolumbar Spinal Deformity Surgery: Guidelines for Treatment

J Bone Joint Surg Am. 2025 Sep 5. doi: 10.2106/JBJS.24.00910. Online ahead of print.

ABSTRACT

➢ For primarily scoliotic deformities, the principles of the modular Lenke classification for adult idiopathic scoliosis can be used to guide level selection.➢ For hyperkyphotic deformities, the upper end vertebra is a suitable upper instrumented vertebra. The sagittal stable vertebra or the first lordotic vertebra is appropriate for the lower instrumented vertebra when fusion to the sacrum is not required.➢ Pelvic fixation can be considered in cases of sagittal and coronal malalignment when ≥4 levels of fusion to the sacrum are planned, L3 to L5 3-column osteotomies are planned, the patient has osteoporosis, or significant disc degeneration or stenosis exists at L5 to S1.

PMID:40911657 | DOI:10.2106/JBJS.24.00910

Mean Body Mass Index Does Not Increase or Decrease at 10 Years After Primary Total Hip or Knee Arthroplasty

J Bone Joint Surg Am. 2025 Sep 5. doi: 10.2106/JBJS.24.01401. Online ahead of print.

ABSTRACT

BACKGROUND: Although patients often aim to lose weight after total hip arthroplasty (THA) or total knee arthroplasty (TKA), long-term changes in body mass index (BMI) are unknown. We analyzed BMI at 2, 5, and 10 years after primary THA and TKA and determined predictors of BMI change.

METHODS: We identified patients who underwent primary THA or TKA for osteoarthritis between 2001 and 2011 and had a BMI at surgery and at 2, 5, and 10 years postoperatively. This resulted in 763 patients (310 who underwent THA and 453 who underwent TKA). The mean patient age was 66 years, and 60% of patients were female. BMI changes were analyzed with repeated-measures analysis of variance. Multinomial logistic regression determined predictors of BMI change.

RESULTS: Following THA, the mean BMI increased from 30.3 kg/m2 at surgery to 30.9 kg/m2 at both 2 years (p = 0.003) and 5 years (p = 0.002). Following TKA, the mean BMI increased from 32.7 kg/m2 at surgery to 33.1 kg/m2 at both 2 years (p = 0.053) and 5 years (p = 0.040). By 10 years, the mean BMI was 30.6 kg/m2 (p = 0.453) for patients undergoing THA and 32.6 kg/m2 (p = 0.947) for patients undergoing TKA, similar to the BMIs at surgery. At 10 years, 27% of patients who underwent THA and 30% of patients who underwent TKA had a BMI decrease of >5%, whereas 30% of patients who underwent THA and 32% of patients who underwent TKA had a BMI increase of >5%. Female sex among patients who underwent THA increased the odds of a >5% BMI increase at 10 years (odds ratio [OR], 2.1; p = 0.006). Older age among patients who underwent TKA decreased the odds of a >5% BMI increase at 10 years (OR per year, 0.95; p < 0.001).

CONCLUSIONS: Although most patients experienced a BMI change of >5% at 10 years, the mean BMI did not meaningfully change 2, 5, or 10 years after THA or TKA. Arthroplasty should not be viewed as a gateway to BMI improvement for patients overall, but female sex and older age may predict clinically important weight changes 10 years after arthroplasty.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

PMID:40911649 | DOI:10.2106/JBJS.24.01401

Resident Unions in Orthopaedic Surgery

J Bone Joint Surg Am. 2025 Sep 5. doi: 10.2106/JBJS.24.01562. Online ahead of print.

ABSTRACT

Across the United States, there is an increasing trend among medical residents to join unions. Even though these entities have existed for almost 100 years, escalating concerns regarding compensation, working conditions, and other factors have influenced thousands of residents to join unions. Unionization can both positively and negatively affect residents, hospital networks, and the communities that the system serves. Most resident unions are nationally organized, but the laws and rules governing these bodies vary among the 50 states. The individual states regulate the collective bargaining of the union with the health-care system, and physician leaders should be aware of the nuances regarding unions at their workplace setting.

PMID:40911644 | DOI:10.2106/JBJS.24.01562

Health-Care Leadership and Orthopaedic Surgeons: Exploring the Value of an Advanced Degree

J Bone Joint Surg Am. 2025 Sep 4. doi: 10.2106/JBJS.25.00343. Online ahead of print.

ABSTRACT

As the field of health care continues to evolve, it requires physician leaders who are not only clinically strong but also knowledgeable in business, public health, health-care administration, and medical law. In this article, we investigate the benefits and challenges of pursuing advanced graduate-level education for orthopaedic surgeons. Advanced training can assist clinicians in the development of leadership skills and career advancement opportunities and deepen their understanding of the modern complexities of health-care systems. Key takeaways include the importance of strategic thinking, emotional intelligence, and the ability to navigate complex health-care environments. The decision to pursue an advanced degree should align with an individual's career goals and personal circumstances. Advanced degrees and leadership programs may provide the requisite competencies and valuable tools for physicians to lead effectively in an increasingly dynamic health-care environment.

PMID:40906821 | DOI:10.2106/JBJS.25.00343

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