Development of a canine stifle computer model to investigate cranial cruciate ligament deficiency.

Background - Cranial cruciate ligament (CrCL) rupture in the canine stifle is a leading cause of orthopedic lameness in the dog. Several corrective surgical procedures have been developed to return dogs to pre-injury function following CrCL rupture, but no one technique has fully shown superiority in terms of functional outcomes. A complete understanding of canine stifle biomechanics prior to and following CrCL rupture is needed to evaluate the biomechanical rationale of surgical corrective procedures being employed. Research Question - The goals of this study were to 1) develop a three dimensional rigid body canine hind limb computer model to simulate both a CrCL intact and CrCL deficient stifle during the stance phase of gait, 2) describe the stifle biomechanics in the CrCL intact and CrCL deficient stifle, and 3) to systematically assess model parameters which may influence CrCL deficiency. Methods - A three dimensional rigid body computer model representing the skeletal structure of a 32 kg Labrador Retriever was developed using SolidWorks based on boney landmarks. Canine hind limb kinetic and kinematic parameters associated with the stance phase of gait were incorporated into the model from the scientific literature. Model simulation of the stance phase was implemented in COSMOSMotion for the CrCL intact and CrCL deficient stifle. Outcome measures assessed include stifle ligament forces and tibial translation. Parameters thought to be associated with CrCL deficiency were systematically altered to determine the model outcome measure sensitivity. Verification of the model was attempted by comparison to a previously reported hind limb mathematical model and an in vitro study. Results - The CrCL was found to be the primary load-bearing ligament during the stance phase in the CrCL intact stifle. The peak CrCL load of 26% body weight occurred at 40% stance in the intact stifle. The caudal cruciate ligament (CaCL) was found to be the primary load-bearing ligament in the CrCL deficient stifle. The peak CaCL load of 219% body weight occurred at 40% stance in the deficient stifle. Suppression of the CrCL consistently increased CaCL load profiles during stance. The medial collateral ligament and lateral collateral ligament were generally not loaded in the CrCL intact or CrCL deficient stifle. The peak relative cranial tibial translation following suppression of the CrCL in the baseline model was 17.8 mm. These outcome measures were verified through reasonable agreement with a hind limb mathematical model and an in vitro study. Tibial plateau angle (TPA), patellar ligament line of action angle (PLLAA) and femoral condyle radius (FCR) were parameters for which model outcomes were most sensitive. In the CrCL intact stifle the CrCL peak load during stance increased with increasing TPA and increasing PLLAA. In the CrCL deficient stifle the CaCL peak load during stance increased with increasing TPA, increasing PLLAA, increasing FCR, increasing ground reaction force magnitude, increasing muscle force magnitude and increasing body mass. Additionally, the peak relative tibial translation during stance increased with increasing TPA, increasing PLLAA and increasing FCR. Parameters for which model outcome measures were less sensitive include ligament stiffness (all ligaments), CrCL stiffness, ligament prestrain (all ligaments), CrCL prestrain and femoromeniscal friction coefficients. Conclusions - A three dimensional rigid body canine hind limb computer model was developed to simulate both a CrCL intact and a CrCL deficient stifle during the stance phase of gait. This is the first 3D computer model to our knowledge capable of determining ligament forces in the CrCL intact and CrCL deficient stifle and visually describing tibial translation. This study attempts to assess several clinically relevant biomechanical parameters thought to be related to CrCL deficiency

Effects of Surgical Correction for the Treatment of Adult Acquired Flatfoot Deformity: A Computational Investigation

Computational models of the foot/ankle complex were developed to predict the biomechanical consequences of surgical procedures that correct for Stage II adult acquired flatfoot deformity. Cadaveric leg and foot bony anatomy was captured by CT imaging in neutral flexion and imported to the modeling software. Ligaments were approximated as tension only springs attached at insertion sites. Muscle contraction of the gastrocnemius/soleus complex was simulated through force vectors and desired external loads applied to the model. Ligament stiffnesses were modified to reflect Stage II flatfoot damage, followed by integration of corrective osteotomies—medializing calcaneal osteotomy (MCO) and Evans and calcaneocuboid distraction arthrodesis (CCDA)—to treat flatfoot. Joint angles, tissue strains, calcaneocuboid contact force, and plantar loads were analyzed. The flatfoot simulation demonstrated clinical signs of disease evidenced by degradation of joint alignment. Repair states corrected these joint misalignments with MCO having greatest impact in the hindfoot, and Evans/CCDA having greatest effect in the mid- and forefoot. The lateral procedures unevenly strained plantar structures, while offloading the medial forefoot, and increased loading on the lateral forefoot, which was amplified by combining with MCO. The Evans procedure raised calcaneocuboid joint contact force to twice intact levels. Computational results are in agreement with clinical and experimental findings. The model demonstrated potential precursors to such complications as lateral tightness and arthritic development and may thus be useful as a predictor of surgical outcomes. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1047–1054, 201

Role of high tibial osteotomy in chronic injuries of posterior cruciate ligament and posterolateral corner

High tibial osteotomy (HTO) is a surgical procedure used to change the mechanical weight-bearing axis and alter the loads carried through the knee. Conventional indications for HTO are medial compartment osteoarthritis and varus malalignment of the knee causing pain and dysfunction. Traditionally, knee instability associated with varus thrust has been considered a contraindication. However, today the indications include patients with chronic ligament deficiencies and malalignment, because an HTO procedure can change not only the coronal but also the sagittal plane of the knee. The sagittal plane has generally been ignored in HTO literature, but its modification has a significant impact on biomechanics and joint stability. Indeed, decreased posterior tibial slope causes posterior tibia translation and helps the anterior cruciate ligament (ACL)-deficient knee. Vice versa, increased tibial slope causes anterior tibia translation and helps the posterior cruciate ligament (PCL)-deficient knee. A review of literature shows that soft tissue procedures alone are often unsatisfactory for chronic posterior instability if alignment is not corrected. Since limb alignment is the most important factor to consider in lower limb reconstructive surgery, diagnosis and treatment of limb malalignment should not be ignored in management of chronic ligamentous instabilities. This paper reviews the effects of chronic posterior instability and tibial slope alteration on knee and soft tissues, in addition to planning and surgical technique for chronic posterior and posterolateral instability with HTO

A safer technique for the double elevation osteotomy in severe infantile tibia vara

Infantile tibia vara is a deformity of abrupt angulation into varus due to an affection of the postromedial aspect of the proximal tibial physis. The deformity often includes internal tibial torsion and limb length discrepancy. Gradual correction of the deformity is currently the treatment of choice for these challenging cases as it requires less invasive surgery, allows progressive and adjustable correction, permits bone lengthening if needed and achieves a more accurate correction compared to acute correction. Elevation of the depressed medial tibial condyle allows restoration of the joint architecture. Different techniques described to elevate the depressed medial tibial plateau are all technically demanding and carry potential risks of unsalvageable intra-operative complications. The aim of this study is to report the results of a safer technique for the double elevation osteotomy combined with gradual correction using the Ilizarov frame, allowing it to be more reproducible, less technically demanding and avoid those potential complications. This study included 12 limbs in 8 patients (mean age 9 years), all were classified as stage V or VI according to the Langenskiold classification. All osteotomies healed completely in all patients. The mean time in the frame was 23 weeks. The mean preoperative femoral shaft-tibial shaft angle was 36° of varus. This improved to 5° of varus. The mean preoperative femoral condyle-tibial shaft angle was 58°. This improved to 84°. The mean preoperative angle of depressed medial tibial plateau was 63°. This improved to 8°. All patients were maintaining full extension of the knee at the final follow-up, and all patients noticed a significant improvement in their gait pattern. We believe that this technique is safer and less invasive compared to traditional and even newly described techniques for elevating the depressed medial tibial plateau and correcting the deformity in severe infantile tibia vara, which will allow it to be more reproducible

Total knee arthroplasty in patients with extra-articular deformity

AbstractMultiple acceptable options are available for the correction of distal femoral deformity associated with knee arthritis. The treatment modality should be chosen based on the extent of deformity and attention to preservation of the collateral ligaments. Surgical options range from osteotomy alone, arthroplasty with intra-articular correction, or arthroplasty with extra-articular correction. Different implant choices and fixation methods for the osteotomy possess advantages and disadvantages which need to be considered carefully. In addition to discussing principles of management based on current literature, this article includes a case report using a previously undescribed technique using corrective osteotomy, intramedullary nail fixation, and total knee arthroplasty with computer navigation

Reconstruction of malunited diaphyseal fractures of the forearm

The forearm is a complex anatomical and functional unit with unique osseous, soft tissue and articular relationships. Disruption of these important relations can have a significant impact, leading to pain, instability of the radio-ulnar articulation and reduced range of motion. The gold standard for treating forearm fractures in adults remains anatomic reduction, stable plate fixation and preservation of the surrounding blood supply. Failure to achieve these goals may lead to malunion, requiring reconstructive surgery, which can be technically challenging. In this review, we discuss the essential aspects of anatomy and pathomechanics, clinical and radiological assessment and the state of the art in pre-operative planning and deformity correction surgery

Osteotomies around the knee alter alignment of the ankle and hindfoot: a systematic review of biomechanical and clinical studies

Purpose: Emerging reports suggest an important involvement of the ankle/hindfoot alignment in the outcome of knee osteotomy; however, a comprehensive overview is currently not available. Therefore, we systematically reviewed all studies investigating biomechanical and clinical outcomes related to the ankle/hindfoot following knee osteotomies. Methods: A systematic literature search was conducted on PubMed, Web of Science, EMBASE and Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered on international prospective register of systematic reviews (PROSPERO) (CRD42021277189). Combining knee osteotomy and ankle/hindfoot alignment, all biomechanical and clinical studies were included. Studies investigating knee osteotomy in conjunction with total knee arthroplasty and case reports were excluded. The QUality Appraisal for Cadaveric Studies (QUACS) scale and Methodological Index for Non-Randomized Studies (MINORS) scores were used for quality assessment. Results: Out of 3554 hits, 18 studies were confirmed eligible, including 770 subjects. The minority of studies (n = 3) assessed both high tibial- and distal femoral osteotomy. Following knee osteotomy, the mean tibiotalar contact pressure decreased (n = 4) except in the presence of a rigid subtalar joint (n = 1) or a talar tilt deformity (n = 1). Patient symptoms and/or radiographic alignment at the level of the ankle/hindfoot improved after knee osteotomy (n = 13). However, factors interfering with an optimal outcome were a small preoperative lateral distal tibia angle, a small hip–knee–ankle axis (HKA) angle, a large HKA correction (>14.5°) and a preexistent hindfoot deformity (>15.9°). Conclusions: Osteotomies to correct knee deformity alter biomechanical and clinical outcomes at the level of the ankle/hindfoot. In general, these changes were beneficial, but several parameters were identified in association with deterioration of ankle/hindfoot symptoms following knee osteotomy