JBJS

Kienböck Disease: Recent Advances in Understanding and Management

J Bone Joint Surg Am. 2025 May 8. doi: 10.2106/JBJS.24.01090. Online ahead of print.

ABSTRACT

➢ An at-risk lunate (due to anatomic factors) subjected to a trigger event (axial load, embolism, hypercoagulability) leads to the development of lunate osteonecrosis.➢ Children, adolescents, and elderly patients with Kienböck disease respond well to nonoperative treatments, and this should be considered before any surgical intervention.➢ For disease limited to the lunate, treatment decisions should be driven by the condition of the cartilage; intact lunate cartilage can be treated with joint leveling or core decompression, whereas disrupted cartilage surfaces should be bypassed with scaphocapitate or scaphotrapeziotrapezoid arthrodesis. Newer surgical procedures such as wrist arthroscopy and the introduction of contrast-enhanced magnetic resonance imaging have expanded the treatment options for these patients.➢ Once disease extends outside of the lunate, reconstruction with proximal row carpectomy or partial or total wrist arthrodesis should be considered on the basis of which articular surfaces are affected.➢ The new unified classification system and treatment are applicable to almost all patients with Kienböck disease.

PMID:40338997 | DOI:10.2106/JBJS.24.01090

Re-Evaluating the Impact of Including Patients with Bilateral Conditions in Orthopaedic Clinical Research Studies: When 1 + 1 Does Not Equal 2

J Bone Joint Surg Am. 2025 May 7. doi: 10.2106/JBJS.24.01234. Online ahead of print.

ABSTRACT

BACKGROUND: Orthopaedic studies frequently include subjects with bilateral conditions. Failure to account for bilateral conditions can lead to spurious associations. The performance of different methods for addressing this issue, especially in populations that include subjects with unilateral and bilateral conditions, has not been rigorously evaluated. The purpose of the present study was to test 3 different methods for analyzing bilateral data: (1) analyzing all limbs as independent subjects (naïve), (2) randomly selecting 1 limb per subject (random), and (3) accounting for correlation between limbs with use of a linear mixed model (LMM).

METHODS: We simulated a hypothetical randomized controlled trial in which Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were collected at a baseline and a 2-year visit. We simulated 2 scenarios: Scenario 1 (in which there was truly no difference between groups [mean difference = 0]) and Scenario 2 (in which there was truly a difference between groups [mean difference = 10]). We varied the prevalence of bilateral involvement from 10% to 100% within each scenario. We evaluated method performance on the basis of bias (difference from the simulated true effect), power (1 - type-II error), type-1 error rate, and 95% confidence interval (CI) coverage.

RESULTS: Bias (difference from simulated true effect) was similar across all methods. In Scenario 2 (true difference between groups), CI coverage was lowest with use of the naïve method (median, 87.8%; range, 85.3% to 93.5%) relative to the random method (median, 95.1%; range, 94.5% to 95.6%) and the LMM method (median, 95.1%; range, 94.5% to 95.5%). In Scenario 1 (no difference between groups), the type-1 error rate was highest for the naïve method (median, 11.3%; range, 6.7% to 14.7%) relative to the LMM method (median, 4.9%; range, 4.5% to 5.3%) and the random method (median, 5.0%; range, 4.5% to 5.2%).

CONCLUSIONS: Failure to account for bilateral conditions led to biased CIs and an increased type-1 error rate. Due to the fact that bias was similar across the methods, decreased model performance using the naïve method was likely attributable to underestimation of the standard error. Orthopaedic studies involving subjects with bilateral conditions warrant special considerations that can be addressed using simple (random) or more complex (LMM) methods.

CLINICAL RELEVANCE: Adherence to robust methodological practices is an essential but underappreciated component of the translation of evidence into clinical practice. Our work is meant to be educational, providing clinical researchers with the knowledge and skills to address a common challenge within the field.

PMID:40333952 | DOI:10.2106/JBJS.24.01234

Implant-Positioning and Patient Factors Associated with Acromial and Scapular Spine Fractures After Reverse Shoulder Arthroplasty: A Study by the ASES Complications of RSA Multicenter Research Group

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

Outcomes of Transfibular Total Ankle Arthroplasty: Clinical and Radiographic Analysis of 130 Cases with Minimum 5-Year Follow-up

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

A Prospective Double-Blinded Randomized Controlled Trial Comparing the Direct Superior Approach Versus the Posterior Approach for THA

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

Predicting Post-Fracture Recovery with Smartphone Mobility Data: A Proof-of-Concept Study

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

Unlike Acetabular Anteversion, Femoral Anteversion Is Not Associated with the Hip Coronal Morphotype: An Anatomic Basis for a New Hip Morphotype Classification at Total Hip Arthroplasty

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

Complication Rates and Functional Outcomes After Total Ankle Arthroplasty in Patients with Rheumatoid Arthritis

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

Role of the CT Scan in Preoperative Planning for Tillaux-Chaput Fractures in Adults

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

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