J Bone Joint Surg Am. 2024 Aug 7;106(15):1384-1394. doi: 10.2106/JBJS.23.01203. Epub 2024 Jun 5.

ABSTRACT

BACKGROUND: This study aimed to identify implant positioning parameters and patient factors contributing to acromial stress fractures (ASFs) and scapular spine stress fractures (SSFs) following reverse shoulder arthroplasty (RSA).

METHODS: In a multicenter retrospective study, the cases of patients who underwent RSA from June 2013 to May 2019 and had a minimum 3-month follow-up were reviewed. The study involved 24 surgeons, from 15 U.S. institutions, who were members of the American Shoulder and Elbow Surgeons (ASES). Study parameters were defined through the Delphi method, requiring 75% agreement among surgeons for consensus. Multivariable logistic regression identified factors linked to ASFs and SSFs. Radiographic data, including the lateralization shoulder angle (LSA), distalization shoulder angle (DSA), and lateral humeral offset (LHO), were collected in a 2:1 control-to-fracture ratio and analyzed to evaluate their association with ASFs/SSFs.

RESULTS: Among 6,320 patients, the overall stress fracture rate was 3.8% (180 ASFs [2.8%] and 59 SSFs [0.9%]). ASF risk factors included inflammatory arthritis (odds ratio [OR] = 2.29, p < 0.001), a massive rotator cuff tear (OR = 2.05, p = 0.010), osteoporosis (OR = 2.00, p < 0.001), prior shoulder surgery (OR = 1.82, p < 0.001), cuff tear arthropathy (OR = 1.76, p = 0.002), female sex (OR = 1.74, p = 0.003), older age (OR = 1.02, p = 0.018), and greater total glenoid lateral offset (OR = 1.06, p = 0.025). Revision surgery (versus primary surgery) was associated with a reduced ASF risk (OR = 0.38, p = 0.019). SSF risk factors included female sex (OR = 2.45, p = 0.009), rotator cuff disease (OR = 2.36, p = 0.003), osteoporosis (OR = 2.18, p = 0.009), and inflammatory arthritis (OR = 2.04, p = 0.024). Radiographic analysis of propensity score-matched patients showed that a greater increase in the LSA (ΔLSA) from preoperatively to postoperatively (OR = 1.42, p = 0.005) and a greater postoperative LSA (OR = 1.76, p = 0.009) increased stress fracture risk, while increased LHO (OR = 0.74, p = 0.031) reduced it. Distalization (ΔDSA and postoperative DSA) showed no significant association with stress fracture prevalence.

CONCLUSIONS: Patient factors associated with poor bone density and rotator cuff deficiency appear to be the strongest predictors of ASFs and SSFs after RSA. Final implant positioning, to a lesser degree, may also affect ASF and SSF prevalence in at-risk patients, as increased humeral lateralization was found to be associated with lower fracture rates whereas excessive glenoid-sided and global lateralization were associated with higher fracture rates.

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

PMID:40305832 | DOI:10.2106/JBJS.23.01203

J Bone Joint Surg Am. 2024 Jun 5;106(11):939-940. doi: 10.2106/JBJS.24.00413. Epub 2024 Jun 5.

NO ABSTRACT

PMID:40305831 | DOI:10.2106/JBJS.24.00413

J Bone Joint Surg Am. 2025 Apr 29. doi: 10.2106/JBJS.24.00983. Online ahead of print.

ABSTRACT

BACKGROUND: While most total ankle arthroplasty (TAA) procedures utilize an anterior approach for implantation, the Zimmer Biomet Trabecular Metal implant is unique in that it utilizes a lateral transfibular approach. We present the largest mid-term study to date to analyze the implant survivorship and clinical and radiographic outcomes of transfibular TAA at a minimum 5-year follow-up.

METHODS: We retrospectively identified and evaluated 130 ankles (122 patients; mean age, 60.8 years; 50% female) with a mean follow-up of 5.9 years (range, 5.0 to 10.1 years) after primary TAA performed between October 2012 and December 2018. Patient-reported outcome measures (PROMs) included the 12-item Short Form Health Survey (SF-12) Physical Component Summary (PCS) and Mental Component Summary (MCS), Ankle Osteoarthritis Scale (AOS) for pain and disability, and visual analog scale (VAS) for pain. Radiographic measurements for range of motion, coronal and sagittal alignment, and implant subsidence were evaluated. The presence of periprosthetic radiolucency was determined using a 12-zone classification system. Adverse events were reported using the Canadian Orthopaedic Foot and Ankle Society (COFAS) Reoperation Coding System (CROCS).

RESULTS: The cohort had mean postoperative values of 41.5 for the SF-12 PCS, 54.9 for the SF-12 MCS, 2.3 for VAS pain, 19.1 for AOS pain, and 28.5 for AOS disability. The postoperative tibiotalar range of motion was 7.5° of dorsiflexion and 17.3° of plantar flexion. A total of 42 valgus ankles (mean coronal tibiotalar angle, 10.4°; range, 1.0° to 25.3°) and 44 varus ankles (mean, -9.1°; range, -1.0° to -25.0°) were corrected to neutral. Twenty-six ankles (20%) had 1 zone of radiolucency, and none of the ankles had >7 zones. There were 3 cases of cysts (2.3%) and 0 cases of subsidence, septic or aseptic loosening, or fibular nonunion. Adverse events occurred in 47 ankles (36.2%) at a mean of 26.7 months, with the most common reoperation being medial gutter debridement (22 ankles; 16.9%). There were 2 ankles (1.5%) with acute infection treated with debridement, antibiotics, and polyethylene exchange with metal component retention. Overall implant survivorship, defined as retention of the metal components, was 100% at the time of final follow-up.

CONCLUSIONS: The clinical and radiographic data in this study suggest that transfibular TAA is an effective and durable treatment option for end-stage ankle arthritis, with excellent mid-term implant survivorship. Periprosthetic radiolucency was limited and did not lead to implant subsidence or loosening. The most common reoperation was medial gutter debridement.

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

PMID:40299950 | DOI:10.2106/JBJS.24.00983

J Bone Joint Surg Am. 2025 Apr 28. doi: 10.2106/JBJS.24.00830. Online ahead of print.

ABSTRACT

BACKGROUND: The direct superior approach (DSA) is a modification of the posterior approach (PA) that is intended to preserve the iliotibial band and short external rotators, except for the piriformis and conjoined tendon, during total hip arthroplasty (THA). The objective of this study was to compare postoperative pain scores between patients undergoing the DSA versus the PA for THA.

METHODS: This study included 80 patients with symptomatic hip arthritis undergoing primary THA. Patients were prospectively randomized to receive either the DSA or PA for THA. Surgery was undertaken using identical implant designs in both groups, and all patients underwent a standardized postoperative rehabilitation program. Predefined study outcomes were recorded by blinded observers at regular intervals for 2 years after THA.

RESULTS: Patients in the PA and DSA groups had comparable baseline characteristics for age (mean and standard deviation, 67.3 ± 7.4 and 67.8 ± 7.8 years, respectively; p = 0.962), sex (26 male and 14 female patients, and 21 male and 19 female patients, respectively; p = 0.499) and body mass index (29.0 ± 4.3 and 29.1 ± 5.3 kg/m2; respectively; p = 0.298). There was no significant difference between the PA and DSA groups with respect to postoperative pain scores at 24 hours as assessed using the visual analogue scale (4.5 ± 1.2 and 4.2 ± 2.0, respectively; p = 0.312). The overall time to hospital discharge was 43.6 ± 9.7 hours in the PA group and 45.4 ± 8.9 hours in the DSA group. Two patients in the PA group and 1 in the DSA group developed superficial wound infections, which were successfully treated with oral antibiotics. There were no further complications or harm sustained by patients in either treatment group.

CONCLUSIONS: This study showed that the intended benefits of the DSA in preserving the iliotibial band and the short external rotators, except for the piriformis and conjoined tendon, did not translate to any difference in postoperative pain scores when compared with the PA for THA.

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

PMID:40294151 | DOI:10.2106/JBJS.24.00830

J Bone Joint Surg Am. 2025 Apr 28. doi: 10.2106/JBJS.24.01305. Online ahead of print.

ABSTRACT

BACKGROUND: After a lower-extremity fracture, the patient's priority is to regain function. To date, our ability to measure function has been limited. However, high-fidelity sensors in smartphones continuously measure mobility, providing an expansive pre- and post-injury gait history. We assessed whether pre-injury mobility data, combined with demographic and injury data, reliably predicted post-fracture mobility.

METHODS: We enrolled 107 adult patients (mean age, 45 years; 43% female, 62% White, 36% Black, 1% Asian, 1% more than one race) ≥6 months after the surgical treatment of a lower-extremity fracture. Consenting patients exported their Apple iPhone mobility metrics, including step count, walking speed, step length, walking asymmetry, and double-support time. We integrated these mobility measures with demographic and injury data. Using nonlinear modeling, we assessed whether pre-injury mobility metrics combined with baseline data predicted post-fracture mobility.

RESULTS: All models were well calibrated and had model fits ranging from an adjusted R2 of 0.18 (walking asymmetry) to 0.61 (double-support time). Pre-injury function strongly predicted post-injury mobility in all models. After the injury, the average daily step count increased by 65 steps each week (95% confidence interval [CI], 56 to 75). Weekly gains were significantly greater within 6 weeks after the injury (92 daily steps per week; 95% CI, 58 to 127) than 20 to 26 weeks post-injury (19 daily steps per week; 95% CI, 11 to 27; p < 0.001). Greater pre-injury steps were associated with increased post-injury mobility (301 daily steps post-injury per 1,000 steps pre-injury; 95% CI, 235 to 367). Mean walking speed declined by 0.200 m/s (95% CI, -0.257 to -0.143) from injury to 8 weeks post-injury. From 12 to 26 weeks post-injury, the average walking speed increased by 0.071 m/s (95% CI, 0.044 to 0.097).

CONCLUSIONS: These proof-of-concept findings highlight the value of high-fidelity pre-injury mobility data in predicting recovery. Individualized recovery projections can provide patient-friendly counseling tools and useful clinical insight for surgeons.

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

PMID:40294149 | DOI:10.2106/JBJS.24.01305

J Bone Joint Surg Am. 2025 Apr 28. doi: 10.2106/JBJS.24.00489. Online ahead of print.

ABSTRACT

BACKGROUND: Most femoral stem designs used in total hip arthroplasty (THA) take into account the proximal femoral morphotype in terms of lateralization and neck-shaft angle (NSA) but not version. The objective of this study was to analyze the acetabular anteversion and femoral anteversion (FA) values in a large cohort according to the 3-dimensional (3D) morphotype of the proximal femur. Our hypothesis was that FA is an anatomic parameter independent of the coronal morphotype (varus, neutral, valgus).

METHODS: A retrospective study based on prospectively collected data included all patients who underwent, from January 2009 to December 2021, a THA planned on the basis of a low-dose computed tomographic (CT) scan 3D. The anatomic acetabular anteversion was calculated in the anterior pelvic plane. The 3D volume models were used to measure the NSA and the FA. We used a multivariable linear regression model to assess the relationship between the NSA and the other hip parameters.

RESULTS: The study included 849 consecutive patients (430 women and 419 men), with a mean age of 62 ± 15 years and a mean body mass index of 26.8 ± 5.7 kg/m2. The etiology was primary osteoarthritis in 616 patients, osteonecrosis in 141 patients, and dysplasia in 92 patients. The mean NSA was 129° ± 7°. The femoral morphotype was vara in 112 cases and valga in 105 cases. Acetabular anteversion was significantly lower in the vara group (mean, 21° ± 9°) and higher in the valga group (mean, 26° ± 9°) compared with the neutral group (mean, 24° ± 8°) (p < 0.001). The FA did not vary significantly according to the femoral morphotype (mean, 20° ± 12°; p = 0.3), with no significant association found between the NSA and FA (β = -0.004 [95% confidence interval, -0.5 to 0.05]; p = 0.8).

CONCLUSIONS: The FA was not associated with the NSA. A hip morphotype classification combining the NSA and FA is presented for use in guiding preoperative planning in THA. Customized patient-specific stems may be of interest in some morphotypes to accurately restore the hip anatomy.

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

PMID:40294145 | DOI:10.2106/JBJS.24.00489

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.00048. Online ahead of print.

ABSTRACT

BACKGROUND: For patients with rheumatoid arthritis (RA) undergoing total ankle arthroplasty (TAA), conflicting data have been reported regarding complications and patient-reported outcome (PRO) improvement when compared with patients with osteoarthritis (OA). The purpose of this study was to compare complication rates and PROs among patients with RA, primary OA, or posttraumatic arthritis.

METHODS: This was a retrospective study of 1,071 primary TAAs performed at a single institution between March 2000 and October 2020. Minimum follow-up was 2 years. Patients were stratified by indication for TAA (OA, n = 372; posttraumatic arthritis, n = 642; RA, n = 57). Patient demographics, intraoperative variables, postoperative complications, and PRO measures were compared among the groups using univariable statistics. Cox regression was performed to assess the risk of implant failure. The overall cohort had a mean age of 63.4 years, 51.3% were male, and 94.8% were White. The mean duration of follow-up (and standard deviation) was 5.7 ± 3.1 years.

RESULTS: Compared with the OA and posttraumatic arthritis groups, the RA cohort had the lowest mean age (p < 0.001), lowest percentage of males (p < 0.001), and highest American Society of Anesthesiologists (ASA) score (p < 0.001). Univariable analysis showed no significant difference in the infection rate among the groups (p = 1.0). The RA cohort had the highest rate of heterotopic ossification postoperatively (2 of 57, 3.5%; p < 0.040). Cox regression analysis showed no increased risk of implant failure for the RA cohort (p = 0.08 versus the OA cohort, 0.14 versus the posttraumatic arthritis cohort). For the Short Musculoskeletal Function Assessment (SMFA), Short Form (SF)-36, Foot and Ankle Outcome Score (FAOS)-symptoms subscale, and FAOS-activities of daily living subscale, the RA group reported significantly worse scores in the postoperative period (p < 0.001). However, the RA cohort demonstrated improvements in all PROs.

CONCLUSIONS: In the largest single-institution study to date, patients with RA reported poorer PRO scores compared with the OA and posttraumatic arthritis groups but experienced functional outcome improvement from the preoperative baseline.

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

PMID:40279451 | DOI:10.2106/JBJS.24.00048

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.01111. Online ahead of print.

ABSTRACT

BACKGROUND: Tillaux-Chaput fractures (TCFs) occur in the anterolateral rim of the distal tibia. TCFs are often overlooked on radiographic review, increasing the risk of chronic pain, instability, and ankle osteoarthritis. This study evaluated the effect of the computed tomography (CT) scan on preoperative planning for TCFs in adults.

METHODS: A retrospective review of ankle fractures evaluated from 2013 to 2023 at a university hospital was conducted. The inclusion criteria were patients ≥18 years of age who underwent radiographic and CT evaluation and had a TCF that was confirmed by CT. The exclusion criteria included pilon and distal tibial fractures and prior ankle surgery. Three orthopaedic surgeons assessed radiographs, classified TCFs using the Rammelt classification, formulated a treatment plan (conservative versus surgical), and, if a surgical treatment was indicated, determined the patient positioning, fixation type, and approach for the TCF. After evaluating CT images, changes in treatment strategy were recorded. Forward stepwise regression was utilized to analyze variables associated with modifications in preoperative planning.

RESULTS: A total of 481 fractures had ankle radiographs and CT scans; of these, 83 (17.3%) had a TCF. After the CT evaluation, the Rammelt classification and the surgical decision changed by 69.1% and 12.5%, respectively. Changes in patient positioning, the type of fixation, and the surgical approach for a TCF (when surgery was indicated) occurred in 32.1%, 43.8%, and 35.3% of all cases, respectively. Multivariable analysis showed that the detection of a TCF on CT predicted changes in the surgical decision and fixation type, while changes in the TCF classification predicted modifications in the fixation type and surgical approach. Posterior malleolar fractures were the unique predictor of changes in the patient positioning.

CONCLUSIONS: CT evaluation modified the surgical decision, type of fixation, and surgical approach for a TCF in 12.5%, 43.8%, and 35.3% of cases, respectively. Moreover, the detection of a TCF and a change in the classification after CT evaluation were predictors of a change in treatment strategy. These findings underscore the importance of the CT scan in the preoperative planning for TCFs in adults. Therefore, we strongly recommend conducting a CT scan when a TCF is suspected in adult patients.

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

PMID:40279443 | DOI:10.2106/JBJS.24.01111

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.01322. Online ahead of print.

ABSTRACT

BACKGROUND: Rotator cuff tears (RCTs) commonly lead to muscle atrophy, fatty infiltration, and fibrosis, resulting in pain, weakness, and impaired shoulder mobility. These pathological changes are often irreversible and pose substantial treatment challenges. The aim of this study was to evaluate the therapeutic potential of muscle-derived mitochondria (Mito) in mitigating muscle degeneration and fibrosis following RCTs.

METHODS: Sprague Dawley rats were assigned to 3 groups: sham surgery, RCTs treated with Mito, or RCTs treated with phosphate-buffered saline solution (PBS). Following RCTs, in vivo Mito or PBS treatments were administered to the supraspinatus muscles (SSPs) of the rats immediately and then biweekly for 12 weeks. Data were collected on muscle morphology, fibrosis, fatty infiltration, oxidative stress, mitochondrial function, macrophage phenotypes, and serum inflammatory cytokines. In vitro experiments included mitochondria tracking in bone marrow-derived macrophages (BMDMs), characterization of macrophage polarization, and inflammatory cytokine profiling.

RESULTS: Isolated mitochondria preserved their morphology and function. Mito treatment improved muscle wet weight (p < 0.0001) and fiber cross-sectional area (p < 0.0001) while reducing fibrosis (p < 0.0001) and fatty infiltration (p < 0.0001). It upregulated mitochondrial markers cytochrome c oxidase (COX IV) and translocase of outer mitochondrial membrane 20 (TOMM20) (p < 0.0001) and enhanced antioxidative activity, as shown by increased superoxide dismutase (SOD) activity (p < 0.0001), elevated glutathione peroxidase (GSH-PX) levels (p = 0.038), and decreased malondialdehyde (MDA) levels (p = 0.0002). Mitochondrial density and morphology were restored in SSPs after Mito treatment. Additionally, Mito treatment induced an anti-inflammatory macrophage phenotype and reduced pro-inflammatory cytokines in vivo and in vitro.

CONCLUSIONS: Mito treatment mitigated muscle degeneration, improved mitochondrial function, and fostered an anti-inflammatory environment through macrophage modulation, demonstrating its potential as a cell-free therapeutic strategy for RCT-related muscle pathologies.

CLINICAL RELEVANCE: Although this is a preclinical study, its approach offers a novel avenue for improving RCT treatment outcomes. However, further validation in large animal models is needed to address the translational applicability of these findings, given the inherent regenerative capacity of rodent muscles.

PMID:40279441 | DOI:10.2106/JBJS.24.01322

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.01094. Online ahead of print.

ABSTRACT

➢ Bone defect management is challenging, but essential, in revision total knee arthroplasty.➢ Appropriate metaphyseal fixation is crucial for stability and implant support.➢ Allografts have been traditionally used to address large defects, but the advent of highly porous metaphyseal cones and sleeves has attracted attention during the past years.➢ Metaphyseal implants are now available in a variety of shapes and sizes to meet various clinical needs.➢ These devices can successfully fill large defects, can better support revision implants, and can achieve long-term biologic fixation.➢ Very good intermediate-term outcomes have been reported with the available metaphyseal implants, using fully cemented or press-fit stems.➢ More research is warranted to further assess surgical indications and the strengths and weaknesses of the various implants used for metaphyseal fixation.

PMID:40279440 | DOI:10.2106/JBJS.24.01094

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.01057. Online ahead of print.

ABSTRACT

BACKGROUND: The literature on the subjective experience of patients undergoing treatment for periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) is scarce, and treatment success is defined without consideration of patient values. The primary objective of this study was to characterize the experience of patients undergoing PJI management. The secondary and tertiary aims were to identify factors that patients associate with successful treatment and to assess alignment with a 2019 outcome-reporting tool (ORT) by the Musculoskeletal Infection Society (MSIS).

METHODS: Patients treated for PJI at 2 international tertiary arthroplasty centers and for whom no less than 1 year and no more than 5 years had elapsed since their most recent revision surgery were included. From August 2023 to April 2024, patients participated in semistructured interviews with a phenomenological approach-an approach that aims to provide detailed examinations of personal lived experiences and to identify themes regarding how a particular phenomenon is experienced. Interview topics included experiences with primary TJA, PJI diagnosis and management, and patient perceptions of the success of their PJI management. Interviews were transcribed, and a thematic analysis was performed. The concordance between patient-defined and MSIS ORT-defined treatment success was calculated.

RESULTS: Of 27 total patients, 21 (78%) reported considerable mental health impacts during the period from PJI onset to treatment conclusion. In defining successful PJI management, patients consistently emphasized the importance of function, pain relief, mobility, and independence. Nine (33%) of the patients (p < 0.001) did not agree with their MSIS ORT classification of success versus failure.

CONCLUSIONS: PJI is a devastating complication following TJA, and success as defined by patients does not align with success as defined by clinicians. As a result, there is insufficient support offered to patients throughout the PJI management process. Future avenues for research include the exploration of the feasibility and impact of implementing patient-centered care models that feature psychological support.

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

PMID:40279409 | DOI:10.2106/JBJS.24.01057

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.00331. Online ahead of print.

ABSTRACT

BACKGROUND: A lumbosacral hemivertebra poses a unique problem, as it leads to a long compensatory curve above it and an obvious main curve. One-stage posterior hemivertebra resection with short segmental fusion is a standard surgery for patients with congenital scoliosis, but curve progression often occurs after surgery. The objective of this study was to investigate the risk factors for curve progression in patients who underwent 1-stage posterior hemivertebra resection with short segmental fusion.

METHODS: This study included 58 Han Chinese patients with congenital scoliosis who underwent 1-stage posterior hemivertebra resection with short segmental fusion. Baseline information, radiographic parameters, and the Scoliosis Research Society-22r questionnaire were collected preoperatively, 3 months postoperatively, and at the last follow-up. Risk factors for curve progression were evaluated using logistic regression analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS: The mean age at surgery was 7.3 years, and the mean follow-up was 7.5 years. Nine patients (15.5%) were diagnosed with curve progression at the final follow-up. Compared with their preoperative condition, patients exhibited a significant reduction in the main curve (95% confidence interval [CI], 25.2° to 28.9° preoperatively versus 6.8° to 9.4° at 3 months; p < 0.001), compensatory curve (95% CI, 15.0° to 19.8° versus 5.5° to 8.1°; p < 0.001), and coronal balance (95% CI, 12.4 to 16.9 mm versus 7.0 to 10.5 mm; p < 0.001) at 3 months postoperatively. The progression group had larger preoperative pelvic obliquity values than the non-progression group (95% CI, 3.19° to 6.55° versus 2.01° to 2.63°; p = 0.008). The logistic regression analysis revealed that preoperative pelvic obliquity was a significant independent risk factor for curve progression (odds ratio, 1.653; 95% CI, 1.096 to 2.495; p = 0.017). The ROC analysis revealed that preoperative pelvic obliquity had good discriminatory capability (area under the ROC curve, 0.876; 95% CI, 0.677 to 1.000; p < 0.001).

CONCLUSIONS: In summary, preoperative pelvic obliquity was an independent risk factor for curve progression, which means that preoperative measures should be taken to ensure minimal pelvic obliquity in patients in order to effectively prevent curve progression. The presence of pelvic obliquity should alert the surgeon and patients to the high risk of deformity progression and to the need for scheduling more frequent follow-ups as appropriate.

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

PMID:40279408 | DOI:10.2106/JBJS.24.00331

J Bone Joint Surg Am. 2025 Apr 25. doi: 10.2106/JBJS.24.00993. Online ahead of print.

ABSTRACT

BACKGROUND: Traditional Medicare (TM) claims data are widely used by researchers and registries to report survivorship following total knee arthroplasty (TKA). The purpose of the present study was to investigate whether the mass exodus of patients from TM to Medicare Advantage (MA) has compromised the fidelity of TM data.

METHODS: We identified 11,717 Medicare-eligible patients (15,282 knees) who had undergone primary TKA from 2000 to 2020 at a single institution. Insurance type was analyzed, and 84% of TKAs were covered by TM. The rates of survivorship free from revision or reoperation were calculated for patients with TM coverage. The same survivorship end points were recalculated after censoring of patients who transitioned to MA after primary TKA, thereby modeling the impact of losing patients from the TM dataset. Differences in survivorship were compared. The mean duration of follow-up was 10 years.

RESULTS: From 2000 to 2020, there was a decrease in TM insurance (from 94% to 68%) and a corresponding increase in MA insurance (from 0% to 19%) among patients undergoing TKA. Following TKA, 25% of patients with TM coverage switched to MA. For patients with TM at the time of surgery, the 15-year rates of survivorship free from any reoperation or revision were 90% and 96%, respectively. When patients were censored upon transition from TM to MA, the 15-year rates of survivorship free from any reoperation (92% versus 90%; hazard ratio [HR] = 1.2; p = 0.001) or any revision (97% versus 96%; HR = 1.3; p = 0.002) were significantly higher.

CONCLUSIONS: One in 4 patients left TM for MA after primary TKA, effectively making them lost to follow-up within TM datasets. The mass exodus of patients out of TM resulted in falsely elevated estimates of survivorship free from reoperation and from revision, with increasing divergence in survivorship over time, when MA data were excluded. As MA continues to grow, efforts to incorporate these data will become increasingly important.

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

PMID:40279407 | DOI:10.2106/JBJS.24.00993

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.24.00670. Online ahead of print.

ABSTRACT

BACKGROUND: Musculoskeletal abnormalities have been reported among female professional ballet performers due, in part, to intrinsic predispositions related to joint and/or connective tissue laxity and extrinsic effectors such as reduced energy availability, low body mass, and high training volumes that may increase the risk of developing idiopathic scoliosis (IS). The purpose of this investigation was to characterize IS prevalence in this population. We hypothesized that there would be elevated prevalence in female performers and that those with IS would exhibit reduced bone mineral density (BMD), body mass, fat mass, and lean mass.

METHODS: A retrospective analysis of whole-body anteroposterior radiographs was performed on 98 professional ballet dancers (49 male performers [mean age, 25 ± 6 years] and 49 female performers [mean age, 27 ± 5 years]) from a single company. Body composition and BMD were assessed via dual x-ray absorptiometry. The criterion for IS was defined as a Cobb angle of >10°. The frequency of IS was plotted against general-population norms. A t test was used to compare demographic characteristics, anthropometrics, and BMD between performers with and without IS and to compare the Cobb angles between sexes. A Fisher exact test was used to compare the IS prevalence between sexes. The Type-I error was set at α = 0.05.

RESULTS: Compared with male performers, female performers had greater spinal asymmetry (mean Cobb angle, 7.98° [95% confidence interval (CI) width, 1.76°] for men and 4.02° [95% CI width, 1.00°] for women; p = 0.027). The prevalence of IS among male performers (3 [6.12%] of 49) was comparable with the general-population norms (0.31% to 5.60%). Women had an elevated prevalence of IS compared with men (10 [20.41%] of 49; p = 0.037) and with general-population norms (0.65% to 8.90%). Among women, performers with IS were observed to have a reduced percentage of body fat (p = 0.021) and reduced fat mass (p = 0.040) compared with performers without IS.

CONCLUSIONS: Female professional ballet performers demonstrate a heightened prevalence of IS that, in addition to intrinsic predisposition, is associated with modifiable factors such as reduced fat mass commonly associated with reduced energy availability known to impact musculoskeletal health in athletes. Future investigations should seek to determine the prevalence of IS in other young female athlete populations commonly exposed to high degrees of activity and reduced energy availability.

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

PMID:40273227 | DOI:10.2106/JBJS.24.00670

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.24.00857. Online ahead of print.

ABSTRACT

BACKGROUND: At our institution, surgeons were observing cases of failed total knee arthroplasties (TKAs) with surface delamination of the tibial insert fabricated by direct compression molding. The increase in unexpected failure led us to investigate the prevalence of delamination and its causes through the use of retrieval analysis and reviews of clinical, demographic, and radiographic data.

METHODS: Between 2000 and 2019, a total of 519 Exactech Optetrak posterior-stabilized direct-compression-molded polyethylene inserts had been retrieved. To determine prevalence, we utilized institutional usage data, manufacturer sales to our institution, and hospital records to determine the delamination rate. Eighty-six retrieved specimens (16 with delamination) were assessed for oxidation with use of infrared spectroscopy.

RESULTS: Sixty-four (12%) of the 519 inserts had delamination. The delamination rate was 0.36% across the 20-year period. Osteolysis was the reason for revision in 25% of delaminated cases, compared with 4% of non-delaminated cases. The mean oxidation index of the delaminated inserts was 2.67 ± 1.4 (range, 1.2 to 6.6). Delamination was not associated with surgical factors (cement viscosity and tibial insert thickness) or processes associated with manufacturing and implantation of the inserts into the patients (implantation year, shelf life, and packaging and sterilization dates).

CONCLUSIONS: The lack of causative factors for the increase in delamination was perplexing. In 2021, following the completion of our study, the manufacturer determined that since 2004, polyethylene inserts were packaged in "non-conforming" vacuum bags that were missing a secondary barrier layer intended to markedly lessen oxygen permeation. The use of non-conforming bags apparently increased the risk of premature oxidation, delamination, and associated osteolysis.

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

PMID:40273225 | DOI:10.2106/JBJS.24.00857

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.24.01118. Online ahead of print.

ABSTRACT

BACKGROUND: Sarcopenia increases postoperative complication and mortality rates in elderly patients. Although measurement of the psoas muscle area on computed tomography (CT) scans is traditionally used to diagnose sarcopenia, CT is not routine in orthopaedic practice and causes unnecessary radiation exposure. EOS, a low-dose full-body imaging modality, captures musculoskeletal structures in an upright position, offering an alternative for sarcopenia diagnosis.

METHODS: Patients ≥18 years of age were included in this retrospective study if they had undergone non-contrast CT spine and EOS imaging between May 2022 and May 2024. Psoas muscle measurements at L3 and L4 were made using non-contrast CT scans, while thigh muscle measurements were obtained with EOS imaging. Inter- and intra-rater reliabilities were assessed using intraclass correlation coefficients (ICCs). Predicted probabilities for L4-psoas sarcopenia were determined through logistic regression, controlling for demographic covariates and validated with an 80% to 20% train-validate split. Sarcopenia cutoffs for anteroposterior (AP) thigh thickness and lateral (LAT) quadriceps thickness were determined with use of the Youden index.

RESULTS: Sarcopenia was identified in 23.1% of 134 patients (85 female and 49 male; 121 White, 7 Black, and 6 Hispanic) on the basis of L4-psoas muscle index thresholds. EOS and CT measurements showed excellent ICCs (≥0.90). Multivariable regressions identified AP thigh thickness and LAT quadriceps thickness as significant predictors of psoas area and L4-psoas sarcopenia. The area under the receiver operating characteristic curve for identifying L4-psoas sarcopenia was 0.85 for AP thigh thickness and 0.77 for LAT quadriceps thickness. Cutoffs were 12.47 cm (males) and 10.68 cm (females) for AP thigh thickness, and 3.23 cm (males) and 2.20 cm (females) for LAT quadriceps thickness. In the validation cohort of 27 patients, the AP thigh thickness model showed 0.94 sensitivity and 0.89 specificity, while the LAT quadriceps thickness model showed 0.70 sensitivity and 1.00 specificity. Applying these cutoffs to the entire data set showed that 66.7% of males and 75.0% of females with measurements below both cutoffs had sarcopenia.

CONCLUSIONS: EOS is a reliable alternative to CT for muscle mass assessment and sarcopenia diagnosis. EOS may be a valuable tool for assessing sarcopenia without a CT scan, as thigh muscle measurements via EOS correlate well with CT-derived psoas measurements. This imaging modality aids in early sarcopenia diagnosis, potentially enhancing preoperative planning and reducing radiation exposure, unnecessary costs, and resource utilization.

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

PMID:40273215 | DOI:10.2106/JBJS.24.01118

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.24.01212. Online ahead of print.

ABSTRACT

BACKGROUND: Although it is well established that the type of organism can be a risk factor for failure in patients with periprosthetic joint infection (PJI), no study to date has examined the impact of the number of positive cultures on treatment outcomes in patients undergoing 2-stage exchange. The purpose of this multicenter study was to determine the prognostic utility of multiple positive cultures at resection as a predictor of failure following reimplantation.

METHODS: This retrospective multicenter study identified 437 patients with chronic knee PJI who had undergone 2-stage exchange arthroplasty with a minimum of 1 year of follow-up following reimplantation. PJI was defined with use of the 2013 Musculoskeletal Infection Society (MSIS) criteria. Patients with culture-negative PJI were excluded (n = 138). Treatment failure was defined as either any reoperation for infection or PJI-related mortality. Multivariable regression controlling for risk factors for failure after a 2-stage arthroplasty was performed to determine whether ≥2 positive intraoperative cultures at resection can predict outcomes following reimplantation when compared with a single positive culture.

RESULTS: Two hundred and ninety-nine patients were included. At a mean follow-up of 6.2 ± 2.6 years, 48 patients (16.1%) experienced failure. Patients who had a failure were more likely to have had a longer interstage interval (p = 0.038) and were also more likely to have had ≥2 positive cultures at the time of resection arthroplasty (95.8% versus 75.3%; p = 0.001). On regression analysis, ≥2 positive cultures at resection was the only variable that was identified as a risk factor for failure following reimplantation in both the univariate (odds ratio [OR], 7.55 [95% CI, 2.24 to 47.0]; p = 0.006) and multivariable models (OR, 8.12 [95% CI, 2.31 to 51.9]; p = 0.005).

CONCLUSIONS: This is the first study to examine the impact of the number of positive cultures on outcomes in patients with PJI. We found that the presence of ≥2 positive cultures at resection was an indicator of a poor prognosis and resulted in a greater than eightfold increase in the risk of treatment failure in patients undergoing a 2-stage exchange.

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

PMID:40273213 | DOI:10.2106/JBJS.24.01212

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.23.01391. Online ahead of print.

ABSTRACT

BACKGROUND: The aim of this study was to determine the risk factors associated with deep vein thrombosis (DVT) or pulmonary embolism (PE) within 30 days after multilevel adult spinal deformity (ASD) surgery and to develop risk prediction models.

METHODS: A retrospective observational study was conducted using the American College of Surgeons National Surgical Quality Improvement Program database from 2010 to 2019. Current Procedural Terminology (CPT) codes 22843 and 22844 were used to query the database and to identify patients who underwent surgical correction of ASD with ≥7 levels of posterior instrumentation. The primary outcomes were the incidences of, and risk factors for, postoperative DVT and PE. Multiple logistic regression was utilized to identify variables associated with an elevated risk of DVT or PE within 30 days after surgery and to develop prediction models for assessing risk.

RESULTS: A total of 7,445 patients (56% female; 73% Caucasian; mean age, 61 years) met the inclusion criteria. Postoperatively, the rate of any venous thromboembolism (VTE; i.e., DVT or PE) was 3.4% (254 patients), the rate of DVT was 2.0% (151 patients), and the rate of PE was 1.7% (127 patients). The following independent predictors of any VTE were identified: weight (odds ratio [OR], 1.054; 95% confidence interval [CI]: 1.027 to 1.081), age per decade of life (OR, 1.106; 95% CI: 1.012 to 1.209), body mass index (BMI; OR, 1.032; 95% CI: 1.015 to 1.049), medicated hypertension (OR, 1.523; 95% CI: 1.168 to 1.987), chronic corticosteroid use (OR, 2.654; 95% CI: 1.848 to 3.812), American Society of Anesthesiologists (ASA) class (OR, 1.768; 95% CI: 1.426 to 2.192), and total operative time (OR, 1.002; 95% CI: 1.002 to 1.003) (p < 0.05 for all). When incorporated into a single model, total operative time, BMI, ASA class, and chronic corticosteroid use were associated with VTE risk.

CONCLUSIONS: Four major risk factors were identified as being associated with postoperative VTE risk in patients undergoing surgery for ASD. Corticosteroid use for a chronic medical condition was the strongest predictor of VTE risk, followed by ASA class, BMI, and operative time. Knowledge of these risk factors can aid in preoperative risk assessment, informed consent, and medical decision-making, such as in determining the clinical thresholds for VTE testing and chemoprophylaxis.

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

PMID:40273208 | DOI:10.2106/JBJS.23.01391

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.24.01265. Online ahead of print.

ABSTRACT

BACKGROUND: Osseous reconstructive surgery for hip displacement in children with cerebral palsy (CP) consists of proximal femoral reorientation by varus derotational osteotomy (VDRO) combined with pelvic osteotomy when indicated. The rate of recurrent hip instability after the index surgery can be as high as 77%. We evaluated the association between femoral diaphyseal medialization at the VDRO site and recurrent instability. We hypothesized that medialization may modify the hip joint reaction force (HJRF), reducing the femoral remodeling that leads to recurrent coxa valga and instability.

METHODS: A retrospective evaluation of the clinical and radiographic records of 140 patients (280 hips) with CP, Gross Motor Function Classification System (GMFCS) Level IV or V, who had been treated with bilateral VDRO as the index surgery for hip displacement between 1998 and 2012 (mean follow-up, 11.3 years) was conducted. Radiographic measurement of medialization was performed using the medialization index (MeI) preoperatively, at 6 weeks and 12 months postoperatively, and at skeletal maturity. Recurrent instability was defined as the need for revision surgery before skeletal maturity or a final migration percentage (MP) of >40%.The influence of the MeI was determined by Poisson regression with multiple variances. The inter- and intra-observer reliability of the MeI, measured by 4 different observers, was assessed using the Cohen d test.

RESULTS: Groups with and without relapse were comparable preoperatively regarding femoral and acetabular parameters. The baseline MP was higher in the relapse group (p < 0.001). The MeI at 6 weeks postoperatively was significantly lower in the relapse group (p = 0.004, relative risk [RR] = 0.07, 95% confidence interval [CI] = 0.01 to 0.42) than in the no-relapse group in multivariable analysis. The MeI showed good inter- and intra-observer reliability, with a Cohen d of <0.5.

CONCLUSIONS: Patients with greater medialization had lower rates of recurrent hip instability at long-term follow-up. The MeI proved to be reliable as a radiographic measurement, and medialization did not increase mechanical instability.

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

PMID:40273207 | DOI:10.2106/JBJS.24.01265

J Bone Joint Surg Am. 2025 Apr 24. doi: 10.2106/JBJS.25.00101. Online ahead of print.

NO ABSTRACT

PMID:40273198 | DOI:10.2106/JBJS.25.00101