The effects of tibial tray orientation on Weight-Bearing kinematics of the patellofemoral joint for total knee arthroplasty.

Comparison of the clinical outcomes and complications of total shoulder arthroplasty and reverse total shoulder arthroplasty: A systematic review and meta-analysis.

To examine the association between knee valgus angles during single-leg squats (SLS) and single-leg hop landings (SLHL) in female athletes following anterior cruciate ligament reconstruction (ACLR), given the high risk of second ACL injuries related to dynamic knee valgus during landing. This cross-sectional study included 15 female athletes (mean age: 17.2 ± 1.0 years) after ACLR. Kinematic data during SLS and SLHL were collected using a three-dimensional motion analysis system composed of 10 infrared cameras and four force plates. Peak joint angles were analysed, and correlations between SLS and SLHL kinematics were evaluated. Significant positive correlations were found between SLS and SLHL for hip flexion (r = 0.68), hip adduction (r = 0.80), hip internal rotation (r = 0.90), knee valgus (r = 0.95), knee internal rotation (r = 0.99) and ankle eversion (r = 0.79). In both tasks, knee valgus was negatively correlated with hip flexion (SLS: r = -0.68; SLHL: r = -0.62) and hip internal rotation (SLS: r = -0.66; SLHL: r = -0.55) and positively correlated with hip adduction (SLS: r = 0.61; SLHL: r = 0.57). SLS and SLHL kinematics were evaluated approximately one year after ACLR and were significantly associated in female athletes. These findings suggest that the SLS may serve as a practical tool for identifying and addressing dynamic knee valgus during landing. Level III, cross-sectional observational study.

Wearing high heels may adversely affect lower limb biomechanics and increase the risk of knee injury in women. This study aims to investigate gait kinematics and kinetics associated with barefoot and high-heeled walking and evaluate whether wearing high heels increases knee joint loading and alters joint stress patterns in healthy female college students. Twelve healthy female college students participated in this cross-sectional study. A Vicon motion capture system (Vicon, Oxford, UK) and AMTI force platforms (Advanced Mechanical Technology Inc., Watertown) were used to collect synchronized kinematic and kinetic data under 2 walking conditions (barefoot and high heels). Data collection was conducted between March and May 2025. Three-dimensional knee moments were calculated using inverse dynamics based on individual anthropometrics. Paired t tests were used to compare differences between conditions. Compared with barefoot walking, high heels significantly increased hip flexion and ankle plantarflexion angles, and reduced knee flexion during stance (P < .05). At toe-off, hip extension and ankle plantarflexion were also elevated. Kinetic results showed significant differences in peak flexion moment 1, adduction moments 1 and 2, and external rotation (P < .05), while peak extension moment 2 showed no difference. High heels altered the timing of adduction, internal, and external rotation peaks. Patellofemoral joint stress was significantly higher in the high-heeled condition (P < .05). High-heeled walking alters lower limb joint angles, knee moment characteristics, and increases patellofemoral joint stress in young women, suggesting a higher risk of knee injury compared with barefoot walking.

Endohedral-fullerene-based molecular magnets containing a single lanthanide ion demonstrate high blocking temperature and long magnetic relaxation time despite their weak crystal field anisotropy. This work presents a comprehensive ab initio investigation of the spin-vibrational couplings responsible for the unique magnetic properties of endohedral fullerenes with a single magnetic ion, focusing on the Dy@C81N complex as an example. The study reveals that only two molecular vibrations, characterized by translational motion of the ion along the interior surface of the fullerene cage, drive high-temperature magnetic relaxation. These low-frequency modes represent a vibrational bottleneck for magnetic relaxation, similar to the one identified in the single-atom magnets with magnetic ions placed on metal oxide or graphene surfaces. However, the translational motions of the ion inside the fullerene cage can hybridize with the internal rotation of fullerenes in the molecular crystal, resulting in more vibrations strongly coupled to electron spin.

Realizing fluorescence emission from non-aromatic amino acids is a difficult challenge in the development of optical materials in the absence of polymeric backbones and covalent cross-linkers. Herein, a non-covalent approach is used to fabricate a series of bulk glasses exhibiting strong fluorescence from non-aromatic amino acids (ʟ-arginine, ʟ-lysine, ʟ-proline, and ʟ-histidine) by co-assembling them with tetrafluorophthalic acid (FA). FA, amino acids, and non-covalent bonding between them play essential roles in both glass formation and fluorescent properties. The high viscosity and rapid annealing process of the glass formation process effectively prevent the crystallization and packing of FA and amino acids, slow the free internal rotations of the amino acids, and reduce the intermolecular collisions, thus increasing the fluorescence emissions of glasses. FA-amino acids glasses display high fluorescence quantum yields (> 44%) and large Stokes shifts. Their fluorescence performance is maintained even under various harsh conditions, including low temperatures, exposure to organic solvents, and coating with porous materials. Based on their robust anti-freezing adhesion capacity (4.77 MPa at -40°C, 3.30 MPa at -196°C) and long-term stable solid-state luminescence characteristics, these materials show great potential as fluorescent coatings and labeling agents suitable for use at low temperatures.

Abstract Purpose To compare implant type, number and cost, suture number, surgical time, and clinical outcomes between arthroscopic supraspinatus tendon repair using double-pulley suture-bridge (DPSB) and single-row (SR). Methods From December 2016 to August 2022, 87 patients who underwent arthroscopic repair of supraspinatus tendon with either DPSB ( n = 46) or SR ( n = 41) were included. Implant type, number and cost, suture number, and surgical time were compared. Clinical outcomes were evaluated with visual analog scale (VAS), American Shoulder and Elbow Surgeons (ASES), University of California, Los Angeles (UCLA) scores, and range of motion (ROM). Magnetic resonance imaging (MRI) or ultrasound was used to assess structural integrity of the tendon. Results Suture anchors were the sole implant used in DPSB and SR groups; the surgical costs of DPSB group ($1092) and SR group ($1080) were of no significant difference; the implant cost, the suture number, and the surgical time were of no significant difference. At 24 months of follow-up, VAS, ASES, and UCLA scores and ROM were statistically improved in both groups; however, there were statistical differences between both groups in clinical outcomes of VAS, ASES, UCLA scores and forward flexion, abduction, and internal rotation. On the follow-up of MRI or ultrasound, the overall re-tear rate was 15.6% in DPSB group and 27.2% in SR group at 6 months postoperatively. Conclusions DPSB is a novel surgical technique of suture-bridge. Suture anchors were the sole implant used in DPSB and SR groups; DPSB and SR groups achieved comparable implant number and cost, surgical time, and suture number; however, the clinical outcomes of DPSB group were significantly better than SR group, and the re-tear rate of DPSB group was lower than SR group. Level of evidence Level III, retrospective control study.

Adhesive capsulitis (AC) is a painful shoulder condition characterized by limited motion due to fibrosis and contracture of the joint capsule. Secondary AC frequently occurs after upper limb fractures and immobilization, delaying recovery. This retrospective study analyzed 11 patients with post-traumatic AC (< 3months) following non-displaced humeral fractures treated conservatively with a median immobilization period of 25days. The cohort included seven men and four women (mean age 52.6years), five of whom also had rotator cuff injuries. Treatments involved hydrodistension, with glenohumeral drainage in seven cases and subacromial bursa drainage in four cases. Range of motion (ROM), pain (VAS), and functionality (DASH) were assessed at baseline, 1-, 2-, and 3-month post-treatment. Significant improvements in ROM were seen across all planes: flexion increased from 80° to 150°, extension from 15° to 60°, abduction from 55° to 160°, internal rotation from 10° to 85°, and external rotation from 10° to 80° (all p < 0.001). Pain levels (VAS) decreased from a mean score of 8 at baseline to 3 at 3months (p < 0.001), and functional capacity (DASH) improved from a score of 45-10 (p < 0.001). Among the five patients with rotator cuff injuries, despite improved ROM and pain, strength deficits persisted, leading to subsequent arthroscopic repairs. Hydrodistension resulted in significant improvements in ROM, pain relief, and functionality, suggesting it is a promising treatment for post-traumatic AC. Early intervention may aid faster recovery after shoulder immobilization.

Blood flow restriction training (BFRT) has emerged as a promising way to enhance strength and build muscle with low-load exercises. This study was aimed to evaluate the effects of upper limb BFRT on shoulder strength. The literature search encompassed PubMed, Scopus, Ovid, Web of Science, EBSCO, CENTRAL, PEDro, and Google Scholar, with no language restrictions. Included studies were clinical trials investigating the application of BFRT on the upper extremity, specifically assessing shoulder strength in flexion, abduction, internal rotation, and external rotation. The certainty of the evidence was assessed using the GRADE approach. Five studies with 158 subjects were included. The pooled analysis revealed a large effect of BFRT on enhancing flexion strength compared to the control group (Morris' dppc = 1.79, 95% CI: 1.09 to 2.49), and moderate to high effect on internal rotation strength (Morris' dppc = 0.67, 95% CI: 0.24 to 1.01). BFRT did not lead to a statistically significant enhancement in abduction and external rotation strength. This systematic review and meta-analysis suggests that BFRT has the potential to improve shoulder flexion and internal rotation strength. However, its effects on abduction and external rotation appear to be limited. While the results are encouraging, low to very low certainty of the evidence (as assessed by GRADE) indicates that more high-quality trials are needed to confirm these results.

Arthroscopic rotator cuff repair is commonly performed using suture anchors. However, implant-free transosseous (TO) fixation has re-emerged as a cost-effective alternative designed to avoid anchor-related complications. The present study directly compares key clinical outcomes, including pain reduction, functional improvement (assessed by the Oxford Shoulder Score (OSS)), range of motion, and postoperative complications between TO and anchor-based (AB) arthroscopic rotator cuff repair, aiming to determine whether the anchorless approach yields equivalent or superior clinical results. In this retrospective cohort with prospective follow-up, 90 patients (mean age 56.1 ± 8.1 years; 55.6% men) underwent arthroscopic rotator cuff repair between January 2023 and May 2025. Procedures used either TO bone tunnels (n = 42) or double-row AB anchors (n = 48). Pain (visual analogue scale (VAS)), OSS, range of motion, and complications were recorded preoperatively and at 6 and 12 months. Baseline characteristics were comparable between groups. Both techniques produced significant improvements: VAS decreased from 6.9 ± 0.7 to 0.7 ± 0.5, and OSS increased from 12.3 ± 1.5 to 32.5 ± 1.5 at 12 months (p < 0.001). Outcomes did not differ between TO and AB repair (VAS, p = 0.95; OSS, p = 0.23). Flexion and abduction improved to ∼165°, and 90% achieved internal rotation to T10 or higher. Arthroscopic TO rotator cuff repair is a safe and effective alternative to AB methods, providing comparable improvements in pain, shoulder function, and range of motion at one year. Its implant-free design may reduce implant-related complications as supported by prior studies, though these advantages warrant confirmation in future randomized trials.

BackgroundThe efficacy and accuracy of physical examination tests for diagnosing pre-arthritic intra-articular hip pathology remain uncertain. The lack of clarity in sensitivity and specificity of these tests complicates clinical diagnosis and management of these conditions. The purpose of this study was to perform a systematic review of the diagnostic accuracy of various physical examination tests for diagnosing pre-arthritic intra-articular hip pathology.MethodsA systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by searching PubMed, the Cochrane Library, and Embase to identify studies that measured sensitivity and/or specificity of various physical examination tests for diagnosing pre-arthritic intra-articular hip pathology e.g. a labral tear, femoroacetabular impingement (FAI), or microinstability of the hip joint. The search phrase used was: hip AND (exam OR examination) AND pain AND (sensitivity OR specificity).ResultsA total of 15 studies met the inclusion criteria, including a total of 1,378 hips. The patients had a mean age of 37 years, with males comprising 52.6% of the cohort. For diagnosing hip labral tears, the FADIR (Flexion, Adduction, Internal Rotation) test demonstrated the highest sensitivity of 100%, while the FABER (Flexion, Abduction, External Rotation) test demonstrated the highest specificity of 100% based on reference standard comparisons of magnetic resonance imaging (MRI) and direct visualization during hip arthroscopy (HA), respectively. For diagnosing FAI, the IROP (Internal Rotation Over Pressure) test demonstrated the highest sensitivity of 91%, while the FADIR test demonstrated the highest specificity of 47% based on reference standard comparisons of MRI and HA, respectively. For diagnosing hip microinstability, the AB-HEER (abduction–hyperextension–external rotation) test demonstrated the highest sensitivity of 80.6%, while the Prone Instability test demonstrated the highest specificity of 97.6% based on reference standard comparisons of MRI and HA, respectively.ConclusionThis systematic review underscores the variability in the sensitivity and specificity of physical examination tests for diagnosing pre-arthritic intra-articular hip disorders. These results may provide clinicians with critical guidance on selecting the most accurate tests for effective diagnosis and management.

BackgroundObjective assessment of hip range of motion (ROM) is essential in evaluating femoroacetabular impingement syndrome (FAIS), yet most studies focus on passive ROM or laboratory-based analyses. Our team previously validated a portable, single-sensor inertial measurement unit (IMU) system for accurate hip ROM assessment (Sensors 2023, 23, 8782). Building on this, we conducted the first study to use IMUs for clinical evaluation of active hip ROM in FAIS patients.PurposeTo compare active ROM between FAIS patients and healthy controls using IMUs, and to explore whether deficits are present even in positions not typically limited by mechanical impingement.MethodsA total of 53 FAIS patients scheduled for hip arthroscopy were compared to 49 healthy matched controls. Active ROM was assessed using inertial measurement unit (IMU) sensors, with measurements taken in standing and prone positions. Outcomes included flexion, external rotation, internal rotation, and total rotation ROM.ResultsFAIS patients demonstrated significant reductions in active ROM across most parameters. Notably, internal rotation in the prone position—a posture not mechanically limited by femoroacetabular contact—was also significantly restricted. Additionally, the contralateral (non-symptomatic) hip in FAIS patients exhibited reduced ROM compared to controls.ConclusionThis study demonstrates the first clinical use of IMUs to capture active ROM deficits in FAIS, revealing functional limitations even in non-conflict positions. These findings may indicate broader neuromuscular or biomechanical adaptations beyond mechanical impingement.Clinical Relevance: IMU-based assessment provides a practical tool for identifying functional impairments in FAIS patients, supporting more targeted diagnosis and individualized rehabilitation strategies.

BackgroundMassive irreparable rotator cuff tears (MIRCTs) present challenges in terms of traditional treatments and can result in pain and functional impairment. Due to the limitations of traditional treatments for MIRCTs, alternative options such as superior fulcrum reconstruction (SFR) using the autologous peroneus longus tendon (PLT) have been explored. This study aims to evaluate the clinical and radiographic outcomes of SFR with autologous PLT grafts for the treatment of MIRCTs after a minimum follow-up period of 1 year.MethodsThis was a prospective cohort study. Thirty-six patients with MIRCTs who underwent arthroscopic SFR with PLT grafts were enrolled and prospectively followed for a minimum of 1 year. Clinical and radiographic evaluations were performed preoperatively and at 3, 6, and 12 months postoperatively. Follow-up evaluations included assessments using the American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), visual analog scale (VAS), Quick-Disabilities of the Arm, Shoulder, and Hand (DASH) score, and measurements of shoulder joint range of motion. Radiography and MRI were used to evaluate the acromiohumeral distance (AHD), Hamada grade, and graft integrity. Repeated measures ANOVA was used to analyze the within-group and between-group differences under different conditions, followed by Bonferroni post-hoc tests to compare outcomes in the postoperative alignment subgroups.ResultsAt the 1-year assessment (n = 36), 34 patients (94.4%) healed well and 2 (5.6%) had MRI-confirmed graft failure. Significant improvements were observed in ASES, QuickDASH, SSV, VAS, forward flexion, external rotation, internal rotation, and AHD scores (all P < 0.05). The use of autologous PLT grafts in SFR resulted in favorable functional outcomes, with a high graft healing rate at the 1-year follow-up.ConclusionsSignificant improvements were observed in the ASES, QuickDASH, SSV, VAS scores, and shoulder joint range of motion, highlighting the effectiveness of this approach for patients with MIRCTs.

The purpose of this systematic review is to compare the outcomes and complications of allograft-prosthetic composite (APC) versus megaprosthesis for shoulder arthroplasty with non-oncologic indications. A systematic review was conducted using PubMed, Embase (Ovid), and Cochrane to search for studies through April 2025 that reported outcomes on APC, megaprosthesis, or both with non-oncologic indications. Data was extracted on study details, patient demographics, follow-up durations, surgical indications, outcome measures, range of motion (ROM), surgical complications, and revision rates. Five studies with 157 patients (27 megaprosthesis, 130 APC) met inclusion criteria. Over 25% of the patients were male, and the mean age was 66 years. A majority of patients (n = 155) had undergone prior surgery. Of the four studies that reported ROM, all found improvements post-operatively, which were significant (p < 0.05) for forward flexion (APC and megaprosthesis), abduction (APC), internal rotation (megaprosthesis), and external rotation (megaprosthesis and one of three APC studies). Forty-eight complications and 33 revisions were reported, which both occurred at higher rates following megaprosthesis. Compared to APC, megaprosthesis may offer slightly better postoperative ROM but confers a higher risk profile. These findings should be considered when choosing a shoulder arthroplasty technique with non-oncologic indications.

BackgroundOsteonecrosis of the femoral head after femoral neck fracture (ONFHpoFNFx) is a severe issue in children, leading to significant hip joint dysfunction. Current treatment options for older children are limited and their effectiveness is uncertain. This study introduces a new treatment method called basicervical femoral neck rotational osteotomy (BFNRO) for ONFHpoFNFx in children and adolescents, and evaluates its clinical outcomes.MethodsFrom June 2017 to September 2022, a total of 17 cases (17 hips) of children and adolescents with ONFHpoFNFx underwent BFNRO at our hip-preservation center. The modified Harris hip score (mHHS), range of motion (ROM), and patient satisfaction were recorded for patients with a follow-up period of over one year. Additionally, femoral head collapse, necrotic area repair, lower limb length, and progression of osteoarthritis were observed.ResultsA total of 15 cases (15 hips) were included in this study, with 8 male and 7 female patients. The average age was 12.9 years (range: 10-17 years). Nine cases underwent BFNRO alone, while six cases underwent combined periacetabular osteotomy (PAO). Rotation angles ranged from 70° to 90° for anterior rotation and from 110° to 135° for posterior rotation. Nine patients had femoral neck fixation in a varus position (10° to 30°). With an average follow-up of 28.6 months (range:12.2-72.7 months), the mHHS significantly improved from a preoperative average of 65.2 (range:46-76) to 90.2 (range:80-97) (P<0.001). Only one patient showed femoral head collapse at the final follow-up compared to the immediate postoperative X-ray. Overall, patients experienced no/mild hip pain (VAS=0-3), slight restriction in range of motion (mainly limited internal rotation), and mild limb shortening. Two patients showed progression of osteoarthritis. No infections, joint replacements, or nerve injuries were observed.ConclusionIn children and adolescents with ONFHpoFNFx, BFNRO can achieve good early to mid-term clinical outcomes by transferring the necrotic area out of the weight-bearing zone, effectively preventing femoral head collapse and avoiding early severe osteoarthritis. Additional PAO procedure may be necessary to increase the coverage of the femoral head.

IntroductionThe biomechanical effects of transverse and longitudinal capsulotomy on hip joint stability in arthroscopy have not been thoroughly investigated. This study used fresh-frozen cadavers to evaluate whether rotational stability and traction resistance differ between these two capsulotomy orientations.MethodsTwelve hips from six fresh-frozen cadavers with intact femurs and pelvises were tested under three conditions: intact, post-capsulotomy, and post-repair. Two capsulotomy patterns were created: a 4 cm transverse capsulotomy assuming inter-portal capsulotomy and a longitudinal capsulotomy. Six hips underwent a transverse capsulotomy, and six underwent a longitudinal capsulotomy. The pelvis was fixed using a wooden plate, and an intramedullary nail was inserted into the femur. To assess rotational stability, internal and external torques of 5 Nm were applied at hip extension angles of 15° and 0°, and at hip flexion angles of 15°, 30°, 45°, and 60°. To evaluate traction resistance, a 200 N axial traction force was applied at flexion angles of 0°, 30°, 45°, and 60°.ResultsExternal rotation laxity increased significantly at all flexion angles following transverse capsulotomy, and only at 0° after longitudinal capsulotomy. The change in external rotation laxity was significantly greater in transverse capsulotomy at 15° of hip extension and 0° than longitudinal capsulotomies in post-capsulotomy compared to intact conditions. Internal rotation laxity did not significantly increase after the both types of capsulotomies and following capsular repair. Separation distance under traction force increased significantly after both types of capsulotomies. The separation distance with post-capsulotomy and post-repair at 0° flexion, and with post-repair at 30° flexion was significantly greater in the transverse group, but no significant differences observed in other positions or conditions.ConclusionsThis cadaveric study demonstrated that vertical (longitudinal) capsulotomy results in less external rotation and traction laxity - particularly at 15° extension and 0° flexion - than horizontal (transverse) capsulotomy. These differences were partially retained even after capsular repair. While standard repair improves overall joint stability, surgeons should note that the longitudinal incision tends to be more stable at lower levels of hip flexion.

Abstract We present a new three-parameter family of self-consistent equilibrium models for quasi-relaxed stellar systems that are subject to the combined action of external tides and rigid internal rotation. These models provide an idealised description of globular clusters that rotate asynchronously with respect to their orbital motion around a host galaxy. Model construction proceeds by extension of the truncated King models, using a newly defined asynchronicity parameter to couple the tidal and rotational perturbations. The method of matched asymptotic expansion is used to derive a global solution to the free boundary problem posed by the corresponding set of Poisson-Laplace equations. We explore the relevant parameter space and outline the intrinsic properties of the resulting models, both structural and kinematic. Their triaxial configuration, characterised by extension in the direction of the galactic centre and flattening toward the orbital plane, is found to depart further from spherical symmetry for larger values of the asynchronicity parameter. We hope that these simplified analytical models serve as useful tools for investigating the interplay of tidal and rotational effects, providing an equilibrium description that complements, and may serve as a basis for, more realistic numerical simulations.

Accuracy and Reliability of Remote Shoulder Motion Capturing Methods: A Systematic Review and Meta-Analysis.

Syndesmosis injury healing remains poorly understood, despite its high prevalence in ankle fractures. Unstable syndesmosis is commonly addressed with either syndesmosis screw (SS) or suture button (SB) fixation, and up to 20% of operated ankle fractures may require some form of syndesmosis fixation. However, in biomechanical studies no repair technique fully restores the preinjury rotational stability or the anatomical alignment of the tibiofibular joint. In a study of 39 patients with operatively treated supination external-rotation type 4 and pronation external-rotation type 4 ankle fractures and fixation of an unstable syndesmosis, weightbearing cone beam computed tomography with rotational stress was performed on both ankles at a mean follow-up of 7.8 (range, 6.2-10.3) years to evaluate tibiofibular syndesmosis dimensions and fibular rotation. Sagittal translation of the fibula (ST), anterior width (AW) and posterior width (PW) of the syndesmosis, tibiofibular clear space (TFCS), and fibular rotation (RO) were measured in neutral position and in maximal internal and external rotation. Mean change in measurements between maximal rotations were calculated to represent range of motion of the fibula under rotational stress.ResultsTwenty-six patients had screw fixation (SS) and 13 had suture button (SB) fixation of the syndesmosis. Eight SSs had been removed and 3 were broken. No SBs had been removed. The mean Olerud-Molander Ankle Score was 84.7 (SD 20.3). Fibular rotation demonstrated a mean difference of 2.7 degrees (95% CI, 1.3-4.1; P < .05) compared with the patient's non-injured ankle. Other measurements showed no significant differences; however, we lacked statistical power to detect significant changes in ST, AW, PW, and TFCS.ConclusionExcess fibular rotation persists after healing of ankle fractures with fixed unstable syndesmosis. However, clinical relevance remains unclear and should be explored with larger patient groups.

Tibial deflexion osteotomy (TDO) is performed to correct an increased posterior tibial slope (PTS). Unintended rotation of the osteotomy and the hinge axis (HA) orientation can result in a postoperative deviation of the mechanical medial proximal tibial angle (mMPTA). This study aimed to investigate how internal and external HA rotations affect postoperative mMPTA. Three-dimensional (3D) bone models of ten patients with increased PTS were used to simulate infratuberositary TDO with different HA orientations and closing distances. Postoperative changes in mMPTA were analysed. In total, 440 TDOs were simulated. The PTS changed by 0.9 ± 0.0° per mm of closing distance. TDO perpendicular to the coronal plane of the long-leg radiograph showed no significant change in the postoperative mMPTA. Internal and external rotation of the HA resulted in significant changes in postoperative mMPTA, with absolute changes up to 4.5° ± 0.5°. A TDO oriented perpendicular to the leg's coronal plane preserves the preoperative mMPTA and therefore avoids unintended coronal correction. The mMPTA changed significantly with a rotation of the HA of only 5° and exceeded a postoperative change of ≥2° with 15° of HA rotation. N/A.