Corrective Osteotomy Research Articles (Page 1)

Background/Objectives: Hallux valgus (HV), a common foot deformity, is difficult to quantify beyond traditional angular measurements. This study introduces a novel dynamic distance mapping technique to visualize HV progression and identify spatial features linked to severity. Methods: A retrospective analysis of 335 feet from 178 patients undergoing HV surgery at Hasharon Hospital, Israel (2014–2024), utilized custom Python software to annotate 24 landmarks on preoperative standing anteroposterior radiographs. This generated 276 normalized Euclidean distances, analyzed via Pearson correlation against HV angles (HVA, IMA, DMAA, HIA). Results: Seven distances correlated negatively (r > 0.4, p < 0.05) and seven positively with HVA, involving the distal phalanx, sesamoids, and second metatarsal. Eleven distances showed strong positive correlation (r > 0.4, p < 0.05) with IMA, reflecting displacement patterns. Moderate correlations were observed with DMAA (six negative, r −0.3 to −0.4; two positive, r 0.3 to 0.4, p < 0.05) and HIA (two negative, r −0.3 to −0.4, p < 0.05). Visualizations highlighted progressive spatial changes. Conclusions: Dynamic distance mapping provides valuable insights into hallux valgus (HV) progression, as evidenced by significant correlations with HVA and IMA, supporting its potential role in surgical planning. However, its ability to capture 3D deformities requires validation against weightbearing computed tomography (WBCT). Future research should explore correlations with specific indications for corrective osteotomies to enhance clinical applicability.

Interbody cage use on successful spinal correction in pedicle subtraction osteotomy for adult spinal deformity surgery: a systematic review and meta-analysis of comparative studies.

Paediatric coronal-plane angular knee deformities are very common and should be corrected before skeletal maturity to prevent significant morbidity in adulthood. Hemi-epiphysiodesis using bone staples was traditionally used for correction, but this is now most often performed using tension band plating. However, these implants are costly and therefore we believe that there is still a role for bone staples in low- and middle-income countries (LMICs). Results of a 30-year retrospective, single-centre study of bone stapling performed for angular knee deformity correction in Trinidad showed that of 121 knees stapled, only 12 (10%) of these eventually required corrective osteotomies. Although our complication rate of 36.4% was higher than previous studies, two-thirds of these children had underlying bony pathology, which is known to increase complication rates. Physeal stapling has a proven record of successful deformity correction and remains suitable for LMICs owing to its low cost.

Rotational malunion of forearm fractures may severely impair pronosupination. Accurate preoperative assessment of torsional deformities is therefore critical, yet no standardized technique exists to quantify axial rotation of the radius and ulna, and the validity of using the contralateral limb as a reference remains uncertain. This study aimed to develop a simple, reproducible CT-based method for measuring forearm torsion and to determine side-to-side anatomical symmetry in normal individuals. A manual measurement technique based on cross-sectional two-dimensional CT images was applied to 30 normal right forearms by two independent observers. Torsion angles were calculated between defined proximal and distal axes of the radius and ulna. Inter- and intraobserver reliability was assessed using Pearson correlation. To analyse bilateral symmetry, automated measurements were obtained from 490 paired radii and 451 paired ulnae from the three-dimensional CT scans obtained from the Stryker Orthopaedic Modeling and Analytics imaging database of healthy volunteers. Measurements were performed using consistent bony landmarks. The two-dimensional CT scan method demonstrated excellent reproducibility for radial torsion (interobserver r = 0.89; intraobserver r = 0.95) as well as for ulnar torsion, using the radial notch as a proximal landmark (Pearson co-efficient r = 0.81 and r = 0.93). In three-dimensional CT scan analysis, right-left torsion differences were <15° in 98% of radii and 91% of ulnae, with correlation coefficients of 0.6-0.8 across measurements. The measurements based on standard axial slices of two-dimensional CT scans provide a reliable and clinically feasible tool to quantify forearm torsion. In over 90% of individuals, the contralateral limb may serve as a valid reference, supporting its routine use in preoperative planning of corrective derotational osteotomies for forearm malunion. III.

Innovative imaging-based pre-operative planning for correction of proximal femur malunion with implants in-situ using Picsart and PowerPoint.

Recent advancements in medical technology have introduced three-dimensional (3D) printing as a promising adjunct to conventional osteotomy. This review aims to evaluate the clinical, radiological outcomes and complications of patients who underwent conventional osteotomy compared to osteotomy with the adjunct use of 3D printing in paediatric deformity correction. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The current study searched from inception to April 2023. All studies that compared outcomes between conventional osteotomy and osteotomy with the adjunct use of 3D printing in paediatric deformity correction in both upper and lower limbs were included. A total of 13 publications with 482 patients were included in this review. In terms of intraoperative parameters, the 3D group had a shorter operative time by 21.3 min [95% confidence interval (CI): 15.92-26.85] and less radiation exposure of -3.42 times (95% CI: -4.57 to -2.28). For radiological outcomes, 3D group had a smaller mean osteotomy error of -2.03 degrees (95% CI: -3.84 to -0.22) and 1.94 times higher odds (95% CI: 1.08-3.48) of having better radiological outcomes. The conventional osteotomy group has possibly a 1.4 risk (95% CI: 0.32-1.59) of growth plate, articular or risk of avascular necrosis compared to 3D templated group. The findings of this meta-analysis support the use of 3D printing as an adjunct in paediatric deformity correction for better intraoperative outcomes, reduce radiation exposure and better radiological accuracy in both upper and lower limb surgery.

Computer-assisted techniques for corrective osteotomies of the lower extremities began to gain significant traction around 2015 with the introduction of 3D-printed, patient-specific instruments. Balgrist University Hospital was among the pioneers in this field, developing innovative solutions in the last decade that are now applied in clinical practice.My talk will trace the evolution of computer-assisted surgery for deformity correction in the lower extremities, emphasizing key advancements that have shaped the current state-of–the-art in research and treatment.In preoperative 3D planning, each step of the surgery is simulated using 3D models of the patient's anatomy to accurately quantify the parameters relevant for navigation. The simplest and most common approach involves a purely static, geometric analysis of the bone anatomy. However, with the integration of biomechanical models, we are transitioning to functional planning, emphasizing the restoration of biomechanical functionality of the joint or limb. Advances in diagnostic imaging are further enhancing 3D planning capabilities, enabling 3D reconstructions from low-dose CT or 2D X-rays to minimize radiation exposure, as well as multimodal data fusion for the integration of soft tissue and cartilage structures.Patient-specific instruments (PSI) continue to be the primary tool for accurate, navigated execution of 3D-planned corrective osteotomies. They integrate seamlessly into surgical workflows and are particularly effective for stabilizing bone fragments in situ. Today's PSI portfolio covers nearly all extra- and intra-articular corrections for the foot, knee, and hip, including highly complex procedures such as femoral head reduction osteotomies. However, a major limitation of PSI remains their lack of adaptability, as corrections are pre-determined with little possibility for intraoperative adjustments. This limitation has revitalized research into optically-guided osteotomies, driven by emerging technologies like augmented reality.Despite its potential, computer-assisted corrective osteotomies have not yet been established as the standard of care. Future research should therefore also focus on reducing costs and effort, simplifying workflows, and broadening the technology's applications.

Evaluation of K-wires splinting of first and second metatarsals following proximal open wedge osteotomy for hallux valgus correction.

BACKGROUND: Knee flexion contracture is one of the most common deformities in children with cerebral palsy, significantly affecting the patients’ gait, energy expenditure, verticalization, and quality of life. Knee flexion contracture can be corrected using either soft tissue procedures (hamstring lengthening) or bony interventions (femoral extension osteotomies). Soft tissue procedures are considered less invasive and are justified based on the underlying pathology. Some studies have reported their effect on sagittal balance, specifically an increase in anterior pelvic tilt. Femoral extension osteotomies have been regarded as sagittally neutral; however, most studies included them as part of combined interventions, which precludes assessment of the isolated effect of the osteotomy itself. This emphasizes the importance of investigating the impact of femoral extension osteotomies on global sagittal alignment in children with cerebral palsy. AIM: This study aimed to evaluate the effect of corrective femoral extension osteotomy on sagittal spinopelvic parameters in children with cerebral palsy and knee flexion contracture. METHODS: The study included 14 patients with cerebral palsy treated at the Turner National Medical Research Center for Children’s Orthopedics between 2022 and 2025. The patients underwent corrective supracondylar femoral extension osteotomy with plate fixation with angular stability (LCP PHP 90°). Overall, 26 osteotomies were performed. In three cases, a newly developed implant designed for patients with cerebral palsy with reduced bone density was used. Clinical outcomes (i.e., active extension deficit, contracture degree, and popliteal angle) and radiological parameters (i.e., pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, and sagittal vertical axis) were assessed preoperatively and at 6 months postoperatively. RESULTS: Significant correction of contracture and improvement in active knee extension were observed. Among the radiological parameters, only lumbar lordosis showed a significant change (+4.3° ± 13.5°, p = 0.049). Other parameters remained unchanged. No associations were found between the changes in clinical and radiological parameters. CONCLUSION: Femoral extension osteotomy is an effective method for correcting knee flexion contracture in children with cerebral palsy and does not cause global sagittal alignment disruption. The increase in lumbar lordosis is adaptive in nature and is not associated with signs of decompensation. Initial experience with the newly designed implant demonstrated technical reliability of fixation and promising applicability in patients with reduced bone density.

This study aimed to propose and evaluate early debulking combined with corrective osteotomy for treating hand macrodactyly in young patients. A retrospective study included 31 young patients (mean age 12.7 years) with severe hand macrodactyly. All underwent microsurgical debulking based on multiple pedicled flaps and osteotomy to reduce the volume soft tissues and shape the deformed finger, with a mean follow-up of 3.1 years. Clinical evaluations included ratios of finger length, circumference, and nail dimensions to the intact finger, as well as the range of motion (ROM) of metacarpophalangeal joint (MCPJ), and functional scores (Kapandji, ARAT, Barthel) before and after surgery. Vancouver Scar Scale scores, parent satisfaction, and complications were also assessed. The procedure preserved the finger, avoided ablation, and restored near-normal appearance. Preoperatively, affected fingers were 1.3 times longer, with PIPJ and DIPJ circumferences 1.5 and 1.7 times larger than intact fingers. At the last follow-up, these ratios improved to 1.1, 1.2, and 1.2, respectively. Nail length and width, initially 1.7 and 1.6 times larger, normalized to 1.0 and 1.1 times. MCPJ ROM improved from 41° to 69°. Functional scores rose significantly: Kapandji from 6 to 9, ARAT from 33 to 53, and Barthel from 95 to 98. Vancouver Scar Scale averaged 2, and all parents expressed satisfaction. This approach reduces finger volume, preserves fingers, improves functional outcomes, and minimizes adverse impacts on quality of life, offering a promising option for severe hand macrodactyly.

Correction of adouble varus deformity and an increased tibial slope. Medial osteoarthritis (OA) and anterior instability in combination with adouble varus deformity (MPTA < 84°, JLCA > 2°) and an increased tibial slope (> 12°). Femoral varus deformity with lateral distal femoral angle of > 91°, severe lateral cartilage damage, lateral OA, lateral loss of the meniscus. Skin incision medial to the tibial tuberosity of approximately 8-10 cm. Insertion of two converging guide wires directly above the pes anserinus, ascending obliquely above the fibula tip. Check the position of the wires with the image intensifier. Incomplete osteotomy below the guide wires with the oscillating saw. Complete osteotomy of the posterior tibial cortex with achisel to move the hinge anterolateral. Insertion of two Schanz screws in the proximal and distal fragments from anterior. Ascending osteotomy and removal of asmall anterior wedge. Careful opening of the osteotomy with chisels at the level of the posterior tibial cortex. Correction of the tibial reclination with the help of the Schanz screws ("joystick"). Check the correction with the image intensifier in two planes. Osteosynthesis with medial angle-stable plate. Partial weight bearing with 10 kg for 2-6weeks, then gradually increase the load. Range of motion: free. Using the described surgical technique, 28patients (7women, 21men, age: 36.8 years) with chronic anterior instability or recurrent instability were treated. All patients had adouble varus deformity (MPTA < 84°, JLCA > 2°) and aposterior tibial reclination of > 12°. The mean postoperative tibial reclination was 9.1°. The postoperative hip-knee-ankle angle was -0.4°. The Lysholm score increased from an average of 75.2 points to 90.3 points.

Radial head and neck fractures can be difficult to diagnose acutely in the pediatric and adolescent population, especially when radiographic findings are subtle. Visualization of fracture displacement and incongruency of the radiocapitellar joint is highly dependent on ossification of the radial head and arm positioning, leading to missed or inaccurate diagnoses. If these fractures heal with joint subluxation/dislocation or in a position that leads to pain, loss of motion, or functional limitations, corrective osteotomy of the radial neck may be indicated. The goal of radial neck osteotomy is a stable and congruent radiocapitellar joint that provides full elbow and forearm motion. Radial neck osteotomy is challenging given concerns for healing without mechanical impingement, the proximity of critical neurovascular structures, avascular necrosis, and physeal arrest. In addition to restoring alignment, reconstructive surgery should address deficient ligamentous anatomy if necessary to address subluxation of the radiocapitellar joint. We present our surgical technique and case examples of radial neck osteotomy and lateral ulnar collateral ligament advancement for chronic injuries in the pediatric population.

Clinical RelevanceIn recent years, an increased posterior tibial slope has been identified as a nonmodifiable risk factor for anterior cruciate ligament (ACL) injury and increased failure rates after ACL reconstruction (ACLR). To date, the literature consists of clinical case series on slope reducing high tibial osteotomies and reports promising clinical results. However, higher case numbers are still lacking. The goal of the present series of anterior-closed-wedge high tibial osteotomies (ACW-HTO) was to analyze patient-reported outcome measures (PROMs) at a minimum of 2 years. It was hypothesized that an ACW-HTO with secondary ACLR after failed ACL surgery improves clinical outcome as compared with the pre-osteotomy state or can even give sufficient stability to avoid the need for revision ACLR.Material and methodsOne hundred consecutive cases with an ACW-HTO operated between February 2019 and December 2022 were included in 2 surgical centers (57 cases radiographic/51 cases with PROMs Sozialstiftung Bamberg and 43 cases radiographic/35 cases with PROMs Sporthopaedicum Berlin, Germany). The pre-injury (before first injury), the preoperative (before ACW-HTO), and the final postoperative conditions were documented using PROMs.ResultsThe mean follow-up was 36 months (SD ±11, range 24-82), the follow-up rate for the PROMs was 85%. The mean preoperative slope of 14.6° (SD ±2.4°; range 11°-28°), measured according to the method of Dejour and Bonnin, was corrected to a mean of 6.8° (SD ±2.0°; range 0°-12°), P < 0.0001. No relevant complications were noted and no recurrent ACL graft failure was reported within the full follow-up period. Twenty-one patients had not received a revision ACLR after ACW-HTO at final follow-up due to sufficient stability. Prior to the first ACL injury, the mean Tegner activity scale was 7.3 points (SD ±1.7; 3-10) and mean Lysholm score revealed 98 points (SD ±4; range 79-100). Prior to ACW-HTO Tegner Scale was significantly reduced to 3.3 points (SD ±1.8; range 0-9) (P < 0.0001) and Lysholm score revealed 57 points (SD ±28; range 14-94) (P < 0.0001) as compared with the pre-injury level. At final follow-up, mean Tegner activity scale changed to 4.8 points (SD ±1.9; range 0-9), which significantly improved as compared with the pre-osteotomy stage (P < 0.0001). Of 85 patients, 18 achieved their pre-injury Tegner activity level, 2 even reached a level higher than the preoperative level. So the return to pre-injury activity level is 21%. The Lysholm score significantly improved to 83 points. (SD ±18; range 24-100) (P < 0.0001) as compared with the pre-osteotomy stage.ConclusionThe present case series presents the largest published series after ACW-HTO and secondary ACLR. Clinical and radiographic results underline that this procedure is safe and significantly increases the patient's ability to participate in light sports and activities of daily living due to an improved stability. An important fact is that 21% of patients after ACW-HTO have not needed a revision ACLR due to an improvement of stability after the osteotomy.

Cubitus varus deformity is characterized by a complex three-dimensional deformity with varus angulation, internal rotation, and hyperextension, resulting in both cosmetic and functional impairments. Traditional techniques like lateral closing wedge osteotomy often fail to address its multidimensional nature. Recent advancements in medical imaging and 3D printing enable computer-assisted surgical planning and patient-specific instruments (PSI) for precise corrections with reduced surgical complexity. This study evaluates the efficacy of 3D-printed PSI in corrective osteotomy for cubitus varus deformity.A retrospective analysis was conducted on 16 pediatric patients with cubitus varus deformity treated at Chang Gung Memorial Hospital, Linkou form 2020 to 2024. Three-dimensional computed tomography was utilized to facilitate deformity analysis, surgical planning, and simulation. Customized 3D-printed surgical guides were used to enable precise osteotomies and fixations. Outcomes were evaluated using radiographic measurements, elbow range of motion (ROM), carrying angle, and Flynn's criteria.Postoperative evaluations revealed significant improvements. The mean Baumann's angle corrected from 84.4° to 67.3°, while the mean lateral humerocapitellar angle improved from 19.5° to 30.8°. The mean carrying angle improved from −15.8° to 5.9°, with the mean elbow ROM increased from 120° to 145°. Flynn's criteria rated outcomes as satisfactory in 14 cases. One case of postoperative infection resolved with early intervention.3D-printed PSI offers a promising solution in achieving precise, multidimensional corrections for cubitus varus deformity with reduced surgical complexity. Challenges such as radiation exposure, cost, and limitations including small sample size and a retrospective study design necessitate further investigation.

Background. Minimally invasive Chevron and Akin osteotomy (MICA) for hallux valgus is a high-tech procedure, with certain stages potentially being time-consuming and requiring intraoperative fluoroscopic guidance. The aim of the study – to evaluate the impact of the original guide device on the operative time, fluoroscopy time, and radiation exposure during minimally invasive Chevron and Akin osteotomy of the first metatarsal bone. Methods. The study included 42 patients with hallux valgus, divided into two groups. All patients underwent surgery using a minimally invasive technique. The Guiding Device Group consisted of 21 patients who underwent osteotomy with the use of the original guide. The Freehand Group included 21 patients who underwent osteotomy without the guide. At the end of the procedure, the duration of the surgery and the radiation dose – measured using the image intensifier sensors – were recorded. Results. The median duration of surgery in the Guiding Device Group was 25.00 minutes [25.00; 30.00], while in the Freehand Group it was 45.00 minutes [40.00; 57.50]. The observed differences were statistically significant (p 0.001). The mean radiation dose was 0.30±0.06mGy in the group where the guide was used, and 0.79±0.20mGy in the group where guidewires for screws were inserted freehand. The mean difference between the groups for this parameter was 0.49mGy (95% CI 0.39-0.58mGy; p 0.001). Pain intensity assessed by the VAS at 2, 4, and 8 weeks, and at 6 months postoperatively, was lower in patients who underwent surgery with the guide (p 0.05 for all time points). Conclusion. The use of the original guiding device in minimally invasive corrective osteotomies for hallux valgus deformity significantly reduced operative time and radiation exposure for both the patient and the surgeon.

Talocalcaneal coalition (TCC) is one of the most common tarsal coalitions in children. However, current classifications of TCC are limited and focus on histologic or morphologic features without clinical correlation or therapeutic guidance. Moreover, no classification system specifically designed for pediatric populations. We hypothesize that the novel classification system will be clinically relevant, reliable, and easy to use for pediatric TCC management. A total of 43 patients (58 feet) with pediatric TCC confirmed by 3-dimensional CT scans were included in this study. All cases were classified according to the novel classification system: type I (middle facet TCC), type II (posterior facet TCC), and type III (extra-articular TCC). Three pediatric orthopaedic surgeons with varying levels of experience independently classified the 58 cases to assess interobserver agreement. For all patients, we documented the hindfoot alignment (valgus, varus, or neutral), presence of pain, peroneal muscle spasm, tarsal tunnel syndrome, treatment strategies, surgical duration, preoperative and postoperative AOFAS and VAS scores, and complications. A total of 22 type I, 9 type II, and 27 type III TCC cases were identified, with a mean age of 10.9 years. The new classification system demonstrated almost perfect interobserver agreement (kappa=0.90). Type I showed the highest valgus prevalence (59%, 13/22; P=0.004), type II predominant varus (67%, 6/9; P<0.001), and type III neutral alignment (52%, 14/27; P=0.515). Medial displacement calcaneal osteotomy was performed in 14% (3/21) of type I cases, and lateral displacement osteotomy in 42% (5/12) of type II and III cases. All types achieved significant AOFAS/VAS improvement. Type III TCC had the shortest operative time (52min; P <0.001) and no complications. We propose a novel classification system for pediatric TCC that is clinically relevant, reliable, and easy to use. Type I TCC is more often associated with hindfoot valgus, while type II TCC frequently presents with hindfoot varus. Types II and III TCC more commonly require lateral displacement calcaneal osteotomy for varus correction. Type III TCC showed the most favorable surgical outcomes, with the shortest operative times and lowest complication rates among all types. Level III-diagnostic study.

Application value of halo‑pelvic traction in the treatment of severe rigid spinal deformity.

Proximal tibial osteotomy for frontal plane deformities correction.

Objectives:Patient-specific instrumentation (PSI) based on three-dimensional (3D) computed tomography imaging (CT) is increasingly being used for corrective high tibial osteotomies (HTO’s) and distal femoral osteotomies (DFO’s). These PSI cutting guides are based off of measurements on a 3D CT, however plain radiographs are typically used during the pre-operative evaluation to determine the need for an osteotomy, and it is unclear how well measurements on plain radiographs correlate to those performed on 3D CT.The purpose of this study was to evaluate the correlation between measurements of coronal alignment and posterior tibial slope (PTS) on plain radiographs and measurements by semi-automated PSI software on 3D CT. It was hypothesized that coronal and posterior tibial slope measurements on plain radiographs would significantly correlate with measurements on 3D CT by PSI software.Methods:Patients who underwent hip to ankle CT as part of the pre-operative workup prior to a opening wedge (oW) or closing wedge (cW) HTO or DFO from October 2020 to November 2023 were reviewed. Mechanical medial tibial width ratio (mMTWr, Figure 1) and medial PTS (Figure 2) were evaluated pre-operatively by two independent raters, orthopaedic sports medicine fellows, on standing whole-leg radiographs and a lateral radiograph of the knee, respectively. Lateral radiographs were excluded if they were malrotated, defined as greater than 5 mm distance between the posterior aspect of the medial and lateral femoral condyles. The mMTWr and PTS using the full length tibial anatomic axis were measured on 3D CT utilizing semi-automated commercial PSI software (Bodycad, Quebec, Canada) without any surgeon involvement (Figure 3).Intra-class correlation coefficients were calculated to determine the inter-rater reliability between raters and between the raters and the PSI software for each measurement. Pearson’s correlation coefficient and an independent t-test were respectively used to analyze for a correlation and difference between the raters’ and PSI software’s measurements. Significance was set at p<0.05.Results:Complete data sets were obtained for 91 cases (43 oW-HTO, 17 cW-HTO, 24 oW-DFO, 4 cW-DFO, 1 rotational HTO, 1 combined cW-HTO and oW-DFO, 1 combined cW-HTO and cW-DFO). 11 patients were excluded from PTS measurements due to malrotated lateral knee radiographs. Demographics for the cohort are shown in Table 1.The ICC between raters for pre-operative mMTWr measurements was 0.99. The ICC between the raters’ measurements of mMTWr on whole-leg standing radiographs and the PSI measurements of mMTWr based on the 3D CT was 0.99, and these two measurements were significantly correlated (r=0.99, p<0.001). There was no difference between the raters’ (40.8% ± 23.5) and the PSI measurement of mMTWr (41.3% ± 22.1, p>0.05).The ICC’s between raters for pre-operative PTS measurements was 0.82. The ICC between the raters’ measurements of PTS on standard lateral knee radiographs and PSI measurements of medial PTS based on the 3D CT was 0.63, and these two measurements were significantly correlated (r=0.72, p<0.001). There was a significant difference between the raters’ measurements (10.4° ± 3.4) and the PSI measurements of PTS (12.0° ± 3.2, p<0.001).Conclusions:This study found that coronal measurements performed on standard whole-leg radiographs and by semi-automated PSI software on 3D CT and standing whole-leg radiographs are highly correlated with near perfect agreement between modalities. PTS measurements had moderate correlation between plain radiographs and 3D CT, and PTS on lateral knee radiographs was, on average, 1.6° less than 3D CT, which utilizes the full-length tibia. Although the absolute value of slope is different between modalities, these data are important as they confirm that PTS on plain radiographs is a moderately reproducible measurement which correlates highly with 3D CT.Altogether, these data confirm that measurements on standing whole-leg and lateral knee radiographs are reproducible and accurate for evaluating coronal alignment and PTS pre-operatively.

Background: A high and flat acromion seems to be a risk factor for posterior shoulder instability. Biomechanically, the surgical correction of acromial malalignment can restore glenohumeral joint stability. Purpose/Hypothesis: The purpose was to assess (1) the stabilizing effect of a posterior acromial bone graft (PABG) in moderate and severe acromial malalignment (high and flat) and (2) contact patterns under posterior humeral head displacement. It was hypothesized that a PABG would significantly (1) increase resistance to posterior humeral head displacement, (2) restore stability, and (3) increase acromiohumeral contact pressure. Study Design: Controlled laboratory study. Methods: A total of 8 fresh-frozen human cadaveric shoulders, with normal glenoid anatomy, were examined in a shoulder simulator in the load and shift and jerk test positions. Each specimen underwent 5 testing conditions using 3-dimensional printed cutting and reduction guides, with the joint left intact for each condition: (1) severe acromial malalignment, (2) severe acromial malalignment + PABG, (3) moderate acromial malalignment, (4) moderate acromial malalignment + PABG, and (5) corrected acromial alignment. The humeral head was translated posteriorly until reaching either a peak force of 150 N or a maximum posterior displacement of 50% of the glenoid width. Force, displacement, and acromiohumeral contact pressure were recorded. Results: At 30° of flexion, the force needed to displace the humeral head 50% increased by 659% when a PABG was added to a moderately malaligned acromion and by 1249% when a PABG was added to a severely malaligned acromion. At 60° of flexion, it increased by 293% and 348%, respectively. This stabilizing effect increased progressively with increasing displacement (P < .05 for all comparisons after ≥5% of displacement). Compared with acromial correction, a PABG allowed comparable posterior displacement but required different amounts of force, depending on the scenario. At 30° of flexion after 30% of displacement, a PABG provided significantly greater stability (P < .05 for all comparisons). Mean contact pressure was significantly reduced on the rotator cuff and significantly increased on the acromial undersurface in moderate and severe acromial malalignment, whereas a PABG restored acromiohumeral contact pressure comparable with corrective osteotomy, particularly at 30° of flexion. Conclusion: The study provides quantitative evidence showing that a PABG significantly enhanced resistance to displacement and compensated for deficient posterolateral acromial coverage by extending the natural mechanical buttress. Clinical Relevance: Experimentally, a PABG provided comparable or superior stability to that after surgical acromial reorientation while representing a technically simpler and potentially less invasive approach.