Finite element analysis of mechanical stress in a cementless tapered-wedge short stem in the varus position.

BACKGROUND: In recent years, the use of tapered-wedge short stems has increased due to their ability to preserve bones and tendons. Surgical techniques occasionally result in a varus position of the stem, which is particularly pronounced in short stems. Although the varus position is not clinically problematic, there are reports of an increased incidence of stress shielding and cortical hypertrophy. Thus, we evaluated and examined the acceptable range of varus angles using finite element analysis. METHODS: Patients diagnosed with osteoarthritis of the hip joint who had undergone arthroplasty were selected and classified into three types [champagne-flute (type A), intermediate (type B), and stovepipe (type C)]. Finite element analysis was performed using Mechanical Finder. The model was created using a Taperloc microplasty stem with the varus angle increased by 1° from 0° to 5° from the bone axis and classified into seven zones based on Gruen's zone classification under loading conditions in a one-leg standing position. The volume of interest was set, the mean equivalent stress for each zone was calculated. RESULTS: A significant decrease in stress was observed in zone 2, and increased stress was observed in zones 3 and 4, suggesting the emergence of a distal periosteal reaction, similar to the results of previous studies. In zone 2, there was a significant decrease in stress in all groups at a varus angle ≥ 3°. In zone 3, stress increased from ≥ 3° in type B and ≥ 4° in type C. In zone 4, there was a significant increase in stress at varus angles of ≥ 2° in types A and B and at ≥ 3° in type C. CONCLUSION: In zone 2, the varus angle at which stress shielding above Engh classification grade 3 may appear is expected to be ≥ 3°. Distal cortical hypertrophy may appear in zones 3 and 4; the narrower the medullary cavity shape, the smaller the allowable angle of internal recession, and the wider the medullary cavity shape, the wider the allowable range. Long-term follow-up is required in patients with varus angles > 3°.

Biomechanical changes in lower extremity in individuals with knee osteoarthritis in the past decade: A scoping review.

Biomechanic studies can provide a powerful theoretical and scientific basis for studies on knee osteoarthritis (OA), which is of great significance for clinical management as it provides new concepts and methods in clinical and research settings. This study aimed to discuss and summarize biomechanical research on lower extremities in individuals with knee OA in the past ten years. The methodology of this review followed the framework outlined in the Joanna Briggs Institute (JBI) guidelines and strictly followed the checklist for drafting the findings. A literature search was conducted using PubMed, Scopus, Cochrane Library, Embase, Web of Science, Grey literature search in Open Library, and Google Academic databases. Relevant literature was searched from 2011 to 2023. Sixteen studies were included in this scoping review. Biomechanical research on knee OA in the last decade demonstrates that the biomechanics of the hip, knee, and ankle have a profound influence on the pathogenesis and treatment of knee OA. Individuals with knee OA have biomechanical changes in hip, knee, and ankle joints such as a significant defect in the strength of ankle varus muscles, weakness of hip abductor muscle, walking with toes outwards, increased knee adduction moment and angle, and decreased knee extensor moment. As the severity of knee OA increases, the tendency of hip abduction positions also increases. Further research with a longitudinal study design should focus on the determination of the relative importance of different biomechanical and neuromuscular factors in the development and progression of the disease.

Osteotomies for genu varum: should we always correct at the tibia? A multicenter analysis of practices in France.

INTRODUCTION: Tibial correction is often performed during a valgus-producing osteotomy for genu varum. However, overcorrection and the creation of a joint line obliquity (JLO) have been associated with unfavorable functional outcomes after high tibial osteotomy (HTO). The aims of this study were to analyze 1) the corrections obtained after HTO, 2) the rationale behind the indication per the European Society for Sports Traumatology Surgery and Arthroscopy (ESSKA) recommendations, and 3) the correlation between the postoperative corrections obtained and functional outcomes. HYPOTHESIS: A significant number of patients who underwent an isolated HTO did not present an "ideal" theoretical indication based on the preoperative angles and correction targets to be performed. MATERIALS AND METHODS: This multicenter study included 289 isolated HTOs. Demographic and morphometric data were anonymized and compiled in a database. Preoperative radiographic parameters were compared with the ESSKA consensus recommendations on osteotomies for genu varum. The consensus defined the "ideal" indication for performing an HTO as medial tibiofemoral compartment pain with significant tibial varus deformity (medial proximal tibial angle [MPTA] < 85°), no significant femoral varus deformity (lateral distal femoral angle [LDFA] < 90°), an expected postoperative obliquity of less than 5°, and a correction resulting in moderate tibial valgus (postoperative MPTA < 94°). The incidence of patients with an "ideal" theoretical indication for isolated HTO and those with a theoretical indication not perfectly justified by the radiographic data and preoperative planning were recorded. RESULTS: Under the ESSKA consensus criteria, 25.3% (n = 73) of isolated HTOs, 15.6% (n = 45) of isolated femoral osteotomies, 9.3% (n = 27) of double-level osteotomies, and 49.9% (n = 144) of cases where no osteotomy was performed due to the lack of significant extra-articular tibial and/or femoral deformity were deemed justified. The presence of a preoperative femoral deformity and the absence of an "ideal" indication for HTO did not affect the postoperative Tegner Activity Scale or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (p > 0.05). A high preoperative hip-knee-ankle (HKA) angle and MPTA, which indicated less varus, were associated with a greater risk of there being no "ideal" theoretical indication for an HTO (coefficient of determination [R2] = 0.19 and R2 = 1, respectively; p < 0.001). CONCLUSION: This study showed that isolated HTOs in current practice were not justified in a significant number of patients, even though they could lead to tibial overcorrection and excessive JLO. This did not impact the functional results of this series, but it might complicate the performance of a secondary knee arthroplasty. Nevertheless, some young patients in this series underwent a salvage osteotomy outside the "ideal" indications of the European recommendations. LEVEL OF EVIDENCE: IV; case series.

Bone loss on the femoral side in knees with medial osteoarthritis: Implications for kinematically-aligned total knee arthroplasty - A comparative study of lateral distal femoral angle in knees with and without osteoarthritis in the same patients.

BACKGROUND: This study aimed to investigate the difference in lateral distal femoral angle (LDFA) between knees with medial osteoarthritis (mOA) and knees without osteoarthritis, and to explore the validity of the assumption that there is no bone wear on the femoral articular surface in kinematic alignment total knee arthroplasty (KA-TKA). METHODS: The study included 69 patients with mOA on one side of the knee and but no OA on the other side. LDFA, medial proximal tibial angle (MPTA), mechanical hip-knee-ankle angle (mHKA), and arithmetic hip-knee-ankle angle (aHKA) were measured and compared between the knees. Pearson's correlation coefficient and paired t-tests were used for statistical analysis. RESULTS: The LDFA and MPTA were significantly more varus in mOA knees than in knees non-OA knees, with differences of 1.0° ± 2.3° and 0.9° ± 2.0°, respectively. The difference between mHKA of the non-OA side and aHKA of the mOA side was not significant, indicating that it is appropriate to use aHKA as an estimation of postoperative alignment after kinematically-aligned total knee arthroplasty without anatomical correction. However, there was a significant difference in MPTA and aHKA between male and female patients in both mOA and non-OA knees. CONCLUSIONS: The assumption that there is no bone wear on the femoral articular surface is rejectable, and the constant compensation thickness of 2 mm for cartilage wear may not be sufficient. Further research is needed to estimate the amount of bone wear in both femur and tibia side to develop more individualized surgical planning strategies in KA-TKA.

Pure varus posteromedial rotatory instability of the elbow: Radiographic findings, treatment, and outcomes.

INTRODUCTION: Although varus posteromedial rotatory instability (VPMRI) is a subtle elbow injury that involves anteromedial coronoid facet (AMCF) fracture and ligamentous injuries, treatment options and outcomes of VPMRI remains controversial. The aim of this study was to investigate radiographic findings, treatments, and outcomes of a large series of VPMRI. METHODS: We retrospectively reviewed 91 pure VPMRI cases with AMCF fracture (O'Driscoll classification anteromedial type) which were treated at 6 hospitals. Clinical and radiographic outcomes were investigated with a mean follow-up period of 46.8 months using the Mayo elbow performance score (MEPS), and the Quick Disabilities of the Arm, Shoulder and Hand (Quick-DASH) score, and serial plain radiographs. RESULTS: In AMCF fracture, there were 4 cases of subtype 1, 67 cases of subtype 2, and 20 cases of subtype 3. On MRI, complete tears of lateral collateral ligament and medial collateral ligament were observed in 83.1 % (59/71 cases) and 33.8 % (24/71 cases). Operative treatment was performed in 68 cases (74.7 %) including both side fixation in 40 cases (58.8 %), medial side fixation only in 17 cases (25.0 %), and lateral side fixation only in 11 cases (16.2 %). Nonoperative treatment was performed in 23 cases (25.3 %). The mean final MEPS and Quick-DASH scores were 93.7 and 7.9. The overall complication and reoperation rates were 22.0 % and 15.4 %. No significant differences regarding final clinical scores and range of motions were observed between the operative group and the nonoperative group, but significant differences were observed regarding number (p = 0.019) and displacement (p = 0.002) of coronoid fragment, and complication rate (p < 0.001) between the two groups. CONCLUSION: Depending on the pattern of coronoid fragment and the degree of ligamentous injuries, operative treatment of unstable VPMRI using various fixation techniques including coronoid fixation and ligament repair yielded satisfactory final clinical outcomes. However, surgeons should be aware of the high complication and reoperation rates after operative treatment. Stable VPMRI with AMCF fracture involving minimal displacement or small number of fragments can be treated nonoperatively.

In-silico study of the biomechanical effects of proximal-fibular osteotomy on knee joint contact pressure in varus-valgus misalignment.

The aim of this work is to investigate in-silico the biomechanical effects of a proximal fibular osteotomy (PFO) on a knee joint with different varus/valgus deformities on the progression of knee osteoarthritis (KOA). A finite element analysis (FEA) of a human lower extremity consisting of the femoral, tibial and fibular bones and the cartilage connecting them was designed. The FEA was performed in a static standing primitive position to determine the contact pressure (CP) distribution and the location of the center of pressure (CoP). The analysis examined the relationship between these factors and the degree of deformation of the hip-knee angle in the baseline condition. The results suggested that PFO could be a simple and effective surgical treatment for patients with associated genu varum. This work also reported that a possible CP homogenization and a CoP correction can be achieved for medial varus deformities after PFO. However, it reduced its effectiveness for tibial origin valgus misalignment and worsened in cases of femoral valgus misalignment.

Changes in nail position and antirotation blade angles on the risk of femoral head varus in PFNA fixed patients: a clinical review and comprehensive biomechanical research.

BACKGROUND: Femoral head varus triggers poor clinical prognosis in intertrochanteric fracture patients with proximal femoral nail antirotation (PFNA) fixation. Studies present that changes in nail position and screw insertion angles will affect fixation stability, but the biomechanical significance of these factors on the risk of femoral head varus has yet to be identified in PFNA fixed patients. METHODS: Clinical data in PFNA fixed intertrochanteric fracture patients have been reviewed, the relative position of intermedullary nail has been judged in the instant postoperative lateral radiography. Regression analyses have been performed to identify the effect of this factor on femoral head varus. Corresponding biomechanical mechanism has been identified by numerical mechanical simulations. RESULTS: A clinical review revealed that ventral side nail insertion can trigger higher risk of femoral head varus, corresponding numerical mechanical simulations also recorded poor fixation stability in models with ventral side nail insertion, and changes in the trajectory of anti-rotation blade will not obviously affect this tendency. CONCLUSIONS: Ventral side insertion of intramedullary nail can trigger higher risk of femoral head varus in PFNA fixed patients by deteriorating the instant postoperative biomechanical environment, and changes in blade trajectory cannot change this tendency biomechanically. Therefore, this nail position should be adjusted to optimize patients' prognosis.

Irreducible Complex Posterior Elbow Dislocation with Varus Posteromedial Rotary Instability - A Case Report.

Introduction: Elbow dislocations, particularly those associated with varus posteromedial rotary instability, are relatively uncommon. We present the case of a 25-year-old male initially managed nonoperatively for a posterior elbow dislocation, who subsequently experienced irreducible re-dislocation with characteristic fractures of the anteromedial facet and tip of the coronoid, indicative of varus posteromedial rotary instability. Case Report: Following an unsuccessful attempt at closed reduction under general anesthesia, open reduction was performed, revealing the interposition of the posterior capsule of the humero-ulnar joint as the cause of irreducibility. Fixation of the coronoid fracture was undertaken, and the patient exhibited excellent functional outcomes at a 4.5-year follow-up. Conclusion: This case underscores the rarity of irreducible elbow dislocation in the context of varus posteromedial rotary instability and highlights the crucial role of capsular interposition in such cases. Successful open reduction, coronoid fixation, and attentive postoperative care contributed to the patient's favorable long-term functional outcome.

Clinical and Radiological Outcomes of Medial Meniscal Allograft Transplantation Combined With Realignment Surgery.

BACKGROUND: The outcomes of medial meniscal allograft transplantation (MMAT) combined with high tibial osteotomy (HTO) compared with isolated MMAT remain unclear. PURPOSE: To compare the clinical and radiological results of MMAT combined with HTO and isolated MMAT. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This retrospective study included 42 consecutive patients, who were divided into group M (isolated MMAT; n = 22) and group H (MMAT combined with HTO with a varus angle >3°; n = 20). Group differences in subjective knee scores, isokinetic muscle strength test, and radiological outcomes (Kellgren-Lawrence grade, mechanical axis, graft extrusion, graft status, and articular cartilage loss) were compared. RESULTS: The mean follow-up period was 29.2 ± 4.9 months and 27.4 ± 5.3 months for groups M and H, respectively. The Lysholm score improved from 55.4 ± 9.5 to 81.3 ± 9.7 and from 52.6 ± 8.9 to 84.2 ± 10.2 in groups M and H, respectively (both P < .001). The International Knee Documentation Committee subjective score improved from 51.4 ± 10.3 to 79.6 ± 9.4 and from 49.3 ± 11.4 to 81.4 ± 8.3 in groups M and H, respectively (both P < .001). Both groups showed no significant differences in subjective knee scores and isokinetic extensor strength at the final follow-up. The rate of preoperative and postoperative high International Cartilage Regeneration & Joint Preservation Society grade (≥3) did not differ between the 2 groups. Group M showed greater coronal graft extrusion than did group H (3.3 ± 0.7 mm vs 2.7 ± 0.8 mm; P = .014); the rate of pathologic graft extrusion (≥3 mm) was not higher in group M (40.9%) than in group H (20%) with the number of patients available (P = .143). Both groups showed no significant difference in the graft status. Graft tears were observed in 2 patients (9%) in group M and 1 patient (5%) in group H (P = .607). CONCLUSION: Clinical scores significantly improved after isolated MMAT and MMAT combined with HTO compared with preoperative values, and their short-term outcomes were similar. Postoperative graft extrusion was greater in patients who underwent isolated MMAT, implying that active correction of varus alignment during MMAT may help in intra-articular biomechanics.

Tips and Tricks to Save You During Revision Total Knee Arthroplasty.

The number of revision total knee arthroplasties (TKAs) performed annually continues to rise. This article is a summary of a symposium on revision TKAs presented at the 2023 American Association of Hip and Knee Surgeons annual meeting. It will provide an overview of the surgical tips and tricks for exposure and component removal, use of metaphyseal fixation and stems to manage bone loss and optimize fixation, constraint in TKA, as well as how to manage extensor mechanism disruptions with a synthetic mesh reconstruction. LEVEL OF EVIDENCE: V.

Analysis of radiologic parameters and clinical outcomes in supramalleolar osteotomy for varus ankle osteoarthritis: A novel method for evaluating ankle alignment.

BACKGROUND: Solely relying on the tibial ankle surface (TAS) angle for determining the mechanical ankle axis might be insufficient. We introduce a novel method to determine the distance from the center of the talus to the tibial axis (TTD). This study aimed to investigate the association between clinical outcomes and radiological changes before and after supramalleolar osteotomy (SMO), including TAS angle, talar tilt (TT) angle, tibiotalar surface (TTS) angle and TTD. METHODS: Seventy patients who received SMO were enrolled. Radiological changes were measured using weight-bearing anteroposterior imaging. The percentage of talar center displacement (TTDP) was calculated as the difference between postoperative and preoperative TTD, divided by talar width (TW). Clinical assessments were performed using the American Orthopedic Foot and Ankle Society ankle-hindfoot (AOFAS) scale. Differences in the aforementioned indicators before and after the operation were analyzed. We defined ΔAOFAS, ΔTAS, ΔTT and ΔTTS as the difference between postoperative and preoperative values. RESULTS: ΔTTS correlated with ΔAOFAS (r = 0.40, p = 0.008), as did TTDP (r = 0.32, p = 0.035). No correlation was observed between ΔAOFAS and ΔTAS. In the comparison between groups, patients with a TTDP greater than 26.19 exhibited a significantly greater ΔAOFAS. The high intraclass correlation coefficient indicated good reliability of the novel method. CONCLUSION: Solely relying on the TAS angle for tibial correction was insufficient. We found TTD as a novel method to evaluate mechanical ankle joint axis. TTDP and ΔTTS both positively correlated with ΔAOFAS, indicating the usefulness of these radiologic parameters.

Radiologic Assessment of Knee Phenotypes Based on the Coronal Plane Alignment of the Knee Classification in a Korean Population.

Background: The Coronal Plane Alignment of the Knee (CPAK) classification system has been developed as a comprehensive system that describes 9 coronal plane phenotypes based on constitutional limb alignment and joint line obliquity (JLO). Due to the characteristics of Asian populations, which show more varus and wider distribution in lower limb alignment than other populations, modification of the boundaries of the arithmetic hip-knee-ankle angle (aHKA) and JLO should be considered. The purpose of this study was to determine the knee phenotype in a Korean population based on the original CPAK and modified CPAK classification systems. Methods: We reviewed prospectively collected data of 500 healthy and 500 osteoarthritic knees between 2021 and 2023 using radiographic analysis and divided them based on the modified CPAK classification system by widening the neutral boundaries of the aHKA to 0° ± 3° and using the actual JLO as a new variable. Using long-leg standing weight-bearing radiographs, 6 radiographic parameters were measured to evaluate the CPAK type: the mechanical HKA angle, medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), aHKA, JLO, and actual JLO. Results: From 2 cohorts of 1,000 knees, the frequency distribution representing all CPAK types was different between the healthy and arthritic groups. The most common categories were type II (38.2%) in the healthy group and type I (53.8%) in the arthritic group based on the original CPAK classification. The left and upward shift in the distribution of knee phenotypes in the original classification was corrected evenly after re-establishing the boundaries of a neutral aHKA and the actual JLO. According to the modified CPAK classification system, the most common categories were type II (35.2%) in the healthy group and type I (38.0%) in the arthritic group. Conclusions: Although the modified CPAK classification corrected the uneven distribution seen when applying the original classification system in a Korean population, the most common category was type I in Korean patients with osteoarthritic knees in both classification systems. Furthermore, there were different frequencies of knee phenotypes among healthy and arthritic knees.

Long-term outcomes of reconstructive treatment for painful dislocations in patients with cerebral palsy.

Purpose: This report presents the long-term results of the hip joint reconstruction in patients with spastic hip disease through open reduction, proximal femur varus derotation osteotomy, and Dega transiliac osteotomy. Methods: We analyzed retrospectively patients diagnosed with a spastic form of bilateral cerebral palsy with painful hip subluxation or dislocation. All patients underwent the same surgical procedure. The minimum follow-up time was 15 years. The study group comprised 15 patients (22 hips), classified with the Gross Motor Function Classification System as levels IV and V. The hip joint range of motion and anteroposterior X-ray examination at the final follow-up visit were compared with pre-operative data. The pain level was evaluated using the Visual Analogue Scale (VAS), and the femoral head shape was assessed using the Rutz classification. The patients' caregivers answered questions regarding pain during sitting, personal hygiene activities, and at rest. The caregivers' satisfaction with the treatment was also assessed with the Caregiver Priorities and Child Health Index of Life with Disabilities questionnaire. Results: We observed a significant reduction of the hip joint pain and improvement in both radiological hip stability parameters and range of motion at the final follow-up visit. Based on the Rutz classification, one hip remained type B, while the other joints became type A. Reduced pain was reported in all three positions, with the most pronounced improvement during sitting and personal hygiene activities. Interestingly, patients with unilateral hip reconstruction were more prone to pain after reconstruction than those operated bilaterally. Conclusion: Primary reconstruction of the painful hip joint neurogenic dislocation results in a stable joint reduction, pain decrease, and improved quality of life in patients with cerebral palsy. Level of evidence: IV case series.

Intramedullary Plating of Complex Proximal Humerus Fractures: A Case Series.

Objectives: To assess fracture union rates using novel intramedullary plate technique. Post-operative humeral neck-shaft angles, patient range of motion and complication profile were secondary outcomes of interest. Methods: Single surgeon, retrospective case series of surgical technique at major trauma centre in Scotland. A 2.0mm mini-fragment plate was secured to the humeral head to act as an intramedullary strut during fixation in complex proximal humerus fractures. Fracture union and neck-shaft angle were assessed radiologically, whilst range of motion and complication profiles were assessed clinically. Results: Twelve patients were followed up for an average of 10 months post-operatively. All achieved bony union with a mean neck-shaft angle of 128°. Mean range of motion values were 100° forward elevation, 83° abduction, 60° internal rotation and 37° external rotation. Four patients required further surgical intervention- two for hardware prominence, one for adhesive capsulitis and one for subsequent rotator cuff failure. There were no cases of avascular necrosis or infection. Conclusion: This novel technique addresses the established biomechanical propensity of proximal humerus fractures to fail in varus collapse and screw cut-out. This method provides an alternative to arthroplasty in the most severe proximal humerus fractures and is readily adopted via standard orthopaedic kit.

Three-dimensional corrective osteotomy for cubitus varus deformity using patient-matched instruments.

Background: Various methods of two or three-dimensional (3D) corrective osteotomy for cubitus varus deformity have been reported. However, whether 3D correction of cubitus varus deformity is necessary is controversial because of technical difficulties and surgical complications. This study introduced 3D simulations and printing technology for corrective osteotomy against cubitus varus deformities. Moreover, recent studies on the application of these technologies were reviewed. Methods: The amount of 3D deformity was calculated based on the difference in 3D shape between the affected side and the contralateral normal side. Patient-matched instruments were created to perform the actual surgery as simulated. Further, a 3D corrective osteotomy was performed using patient-matched instruments for cubitus varus deformity in pediatric and adolescent patients. The humerus-elbow-wrist angle, tilting angle, and elbow ranges of motion were evaluated. Results: Humerus-elbow-wrist angle and tilting angle were corrected from -21° to 14° and from 30° to 43°, respectively, in the pediatric patient and from -18° to 10° and from 20° to 40°, respectively, in the adolescent patient. The elbow flexion and extension angles changed from 130° to 140° and from 20° to 10°, respectively, in the pediatric patient and from 120° to 130° and from 15° to 0°, respectively, in the adolescent patient. Conclusion: The 3D computer simulations and the use of patient-matched instruments for cubitus varus deformity are reliable and can facilitate an accurate and safe correction. These technologies can simplify the complexity of 3D surgical procedures and contribute to the standardization of treatment for cubitus varus deformity.

Cubitus varus deformity following paediatric supracondylar humeral fracture remodelling predominantly in the sagittal direction: A three-dimensional analysis of eighty-six cases.

PURPOSE: Three-dimensional (3D) capacity for remodelling in cubitus varus deformity (CVD) after paediatric supracondylar humeral fractures (PSHFs) remains unelucidated. This study investigated remodelling patterns after PSHFs by examining 3D deformity distribution over time after injury. METHODS: Computed tomography (CT) data of 86 patients with CVD after PSHFs were analysed. The 3D deformity angles in the sagittal, coronal, and axial directions were assessed and correlated with the duration between the age at injury and CT evaluation. For the subgroup analysis, we performed the same correlation analysis in a younger (< 8 years old) and an older group (≥ 8 years old); we categorized the duration into early (< 2 years), middle (≥ 2 to < 5 years), and late periods (≥ 5 years) and compared the deformity angles of each direction among the three groups. RESULTS: Sagittal deformity showed a moderate correlation with the duration of deformity (r = -0.54; P < 0.001), while coronal and axial deformities showed a negligible correlation. Sagittal deformity showed moderate correlations with the duration in the younger group (r = -0.62; P < 0.001) and weak correlations in the older group (r = -0.37; P = 0.091). In the sagittal direction, the deformity angle in the early period was significantly larger than those in the mid and late periods (P < 0.001). However, there were no significant differences among the three groups in the coronal and axial directions. CONCLUSION: Sagittal deformities in CVDs are capable of remodelling, especially in the early period and at a younger age, whereas coronal and axial deformities are less likely to undergo remodelling.

Computer-Assisted Surgery in Total Knee Arthroplasty: Our Experience.

Background: Total knee arthroplasty (TKA) is a reliable orthopedic procedure for knee osteoarthritis with long-term success rates of 90% after 15 years. Computer-assisted surgery (CAS) has been developed to improve the accuracy of the alignment and orientation of the components in TKA. Methods: A prospective study involving 103 subjects who underwent CAS-TKA was conducted over a 3-year period. Subjects were assessed for pre- and post-operative varus and valgus deformity, BMI, comorbidities, and Knee Society Score (KSS). Outcome measures of post-operative KSS, post-operative alignment, and hospital stay were examined by Spearman correlation coefficients. Categorical outcomes of complication and secondary procedures were compared by chi-squared test and odds ratio. Results: The study considered 103 TKA patients with a mean ± SD age of 63.7 ± 8.4 years (33-88 years). Unilateral knee replacement was performed on 56 patients (54.3%) and remaining 47 (45.6%) had simultaneous bilateral TKA. Forty (34.8%) patients were obese, and severe pre-operative deformity (> 15°) was observed in 47 (31.3%) patients. Mean coronal alignment of the knee joint was 91.33° (SD: 90.69° valgus-88.92° varus). The mean post-operative KSS noted in obese and non-obese subjects were 93.43 (84-98) and 94.76 (85-98) respectively. Post-operative KSS for knees with severe deformity was 94.08 (80-98), while it was 95.76 (83-98) in those with mild to moderate deformities. Conclusion: The study confirms that navigation in CAS-TKA consistently achieved coronal alignment of the knee joint within ± 3°, irrespective of the patient BMI and degree of deformity.

Osteotomy around the painful degenerative varus knee has broader indications than conventionally described but must follow a strict planning process: ESSKA Formal Consensus Part I.

PURPOSE: The European consensus was designed with the objective of combining science and expertise to produce recommendations that would educate and provide guidance in the treatment of the painful degenerative varus knee. Part I focused on indications and planning. METHODS: Ninety-four orthopaedic surgeons from 24 European countries were involved in the consensus, which focused on the most common indications for osteotomy around the knee. The consensus was performed according to an established ESSKA methodology. The questions and recommendations made were initially designed by the consensus steering group. And 'best possible' answers were provided based upon the scientific evidence available and the experience of the experts. The statements produced were further evaluated by ratings and peer review groups before a final consensus was reached. RESULTS: There is no reliable evidence to exclude patients based on age, gender or body weight. An individualised approach is advised; however, cessation of smoking is recommended. The same applies to lesser degrees of patellofemoral and lateral compartment arthritis, which may be accepted in certain situations. Good-quality limb alignment and knee radiographs are a mandatory requirement for planning of osteotomies, and Paley's angles and normal ranges are recommended when undertaking deformity analysis. Emphasis is placed upon the correct level at which correction of varus malalignment is performed, which may involve double-level osteotomy. This includes recognition of the importance of individual bone morphology and the maintenance of a physiologically appropriate joint line orientation. CONCLUSION: The indications of knee osteotomies for painful degenerative varus knees are broad. Part I of the consensus highlights the versatility of the procedure to address multiple scenarios with bespoke planning for each case. Deformity analysis is mandatory for defining the bone morphology, the site of the deformity and planning the correct procedure. LEVEL OF EVIDENCE: Level II, consensus.

Extending the intermedullary nail will not reduce the potential risk of femoral head varus in PFNA patients biomechanically: a clinical review and corresponding numerical simulation.

Femoral head varus is an important complication in intertrochanteric fracture patients treated with proximal femoral nail anti-rotation (PFNA) fixation. Theoretically, extending the length of the intramedullary nail could optimize fixation stability by lengthening the force arm. However, whether extending the nail length can optimize patient prognosis is unclear. In this study, a review of imaging data from intertrochanteric fracture patients with PFNA fixation was performed, and the length of the intramedullary nail in the femoral trunk and the distance between the lesser trochanter and the distal locking screw were measured. The femoral neck varus status was judged at the 6-month follow-up. The correlation coefficients between nail length and femoral neck varus angle were computed, and linear regression analysis was used to determine whether a change in nail length was an independent risk factor for femoral neck varus. Moreover, the biomechanical effects of different nail lengths on PFNA fixation stability and local stress distribution have also been verified by numerical mechanical simulations. Clinical review revealed that changes in nail length were not significantly correlated with femoral head varus and were also not an independent risk factor for this complication. In addition, only slight biomechanical changes can be observed in the numerical simulation results. Therefore, commonly used intramedullary nails should be able to meet the needs of PFNA-fixed patients, and additional procedures for longer nail insertion may be unnecessary.