Abstract

Introduction

Opening wedge high tibial osteotomy is an attractive surgical option for physically active patients with early osteoarthritis and varus malalignment. Unfortunately use of this surgical technique is frequently accompanied by an unintended increase in the posterior tibial slope, resulting in anterior tibial translation, and consequent altered knee kinematics and cartilage loading(1).

To address this unintended consequence, it has been recommended that the relative opening of the anteromedial and posterolateral corners of the osteotomy are calculated pre-operatively using trigonometry (1). This calculation assumes that the saw-cut is made parallel to the native posterior slope; yet given the current reliance on 2D images and the ‘surgeon's eye’ to guide the saw-cut, this assumption is questionable.

The aim of this study was to explore how accurately the native posterior tibial slope is reproduced with a traditional freehand osteotomy saw-cut, and whether novel 3D printed patient-specific guides improve this accuracy.

Introduction. Computer hexapod assisted orthopaedic surgery (CHAOS) has previously been shown to provide a predictable and safe method for correcting multiplanar femoral deformity. We report the outcomes of tibial deformity correction using CHAOS, as well as a new cohort of femoral CHAOS procedures. Materials and Methods. Retrospective review of medical records and radiographs for patients who underwent CHAOS for lower limb deformity at our tertiary centre between 2012–2020. Results. There were 70 consecutive cases from 56 patients with no loss to follow-up. Mean age was 40 years (17 to 77); 59% male. There were 48 femoral and 22 tibial procedures. Method of fixation was intramedullary nailing in 47 cases and locking plates in 23. Multiplanar correction was required in 43 cases. The largest correction of rotation was 40 degrees, and angulation was 28 degrees. Mean mechanical axis deviation reduction per procedure was 17.2 mm, maximum 89 mm. Deformity correction was mechanically satisfactory in all patients bar one who was under-corrected, requiring revision. Complications from femoral surgery included one under-correction, two cases of non-union, and one pulmonary embolism. Complications from tibial surgery were one locking plate fatigue failure, one compartment syndrome, one pseudoaneurysm of the anterior tibial artery requiring stenting, and one transient neurapraxia of the common peroneal nerve. There were no deaths. Conclusions. CHAOS can be used for reliable correction of complex deformities of both the femur and tibia. The risk profile appears to differ between femoral and tibial surgeries

Malalignment is a common complication following tibial surgery, occurring in 10% of fractures. This is associated with prolonged healing time and non-union. It occurs due to inability to maintain a satisfactory reduction. A reduction device, such as the Staffordshire Orthopaedic Reduction Machine (STORM), permits the surgeon to manipulate the fracture and hold it reduced. A retrospective parallel case series was undertaken of all patients undergoing tibial nails over a six-year period from 2014 to 2021. Patient demographics were obtained from medical records. Operative times obtained from the theatre IT system and included the time patient entered theatre and surgical start and finish times for each case. Anteroposterior and lateral long leg post-operative radiographs were reviewed. Angulation was measured in both coronal and sagittal planes, by two separate orthopaedic surgeons. A reduction was classified to be ‘mal-aligned’ if the angle measured was greater than 5 degrees. One tailed unpaired t-test was used to compare alignment in each plane. Bony union was assessed on subsequent radiographs and was determined according to the Radiographic Union Score for Tibial Fractures. 31 patients underwent tibial nail during the time period. 8 patients were lost to follow up and were excluded. Of the remaining 23 patients, the STORM device was utilised in 11. The overall mean alignment was acceptable across all groups at 2.17° in the coronal plane and 2.56° in the saggital plane. Analysing each group individually demonstrated an improved alignment when STORM was utilised: 1.7° (1°–3°) vs 2.54° (0°–5°) for the coronal plane and 1.6° (0°–3°) vs 3.31° (0°–9°) in the saggital plane. This difference was significant in saggital alignment (p=0.03) and showed a positive trend in coronal alignment, although was not significant (p=0.08). The time in theatre was shorter in the control group with a mean of 113 minutes (65 to 219) in comparison to STORM with a mean of 140 minutes (105 to 180), an increased theatre time of 27 minutes (p=0.04). This study demonstrates that STORM can be used in the surgical treatment of tibial fractures resulting in improved fracture alignment with a modest increase in theatre time

Abstract. OBJECTIVE. Knee varus malalignment increases medial knee compartment loading and is associated with knee osteoarthritis (OA) progression and severity. 1. Altered biomechanical loading and dysregulation of joint tissue biology drive OA progression, but mechanistic links between these factors are lacking. Subchondral bone structural changes are biomechanically driven, involve bone resorption, immune cell influx, angiogenesis, and sensory nerve invasion, and contribute to joint destruction and pain. 2. We have investigated mechanisms underlying this involving RANKL and alkaline phosphatase (ALP), which reflect bone resorption and mineralisation respectively. 3. and the axonal guidance factor Sema3A. Sema3A is osteotropic, expressed by mechanically sensitive osteocytes, and an inhibitor of sensory nerve, blood vessel and immune cell invasion. 4. Sema3A is also differentially expressed in human OA bone. 5. HYPOTHESIS: Medial knee compartment overloading in varus knee malalignment patients causes dysregulation of bone derived Sema3A signalling directly linking joint biomechanics to pathology and pain. METHODS. Synovial fluid obtained from 30 subjects with medial knee OA (KL grade II-IV) undergoing high tibial osteotomy surgery (HTO) was analysed by mesoscale discovery and ELISA analysis for inflammatory, neural and bone turnover markers. 11 of these patients had been previously analysed in a published patient-specific musculoskeletal model. 6. of gait estimating joint contact location, pressure, forces, and medial-lateral condyle load distribution in a published data set included in analyses. Data analysis was performed using Pearson's correlation matrices and principal component analyses. Principal Components (PCs) with eigenvalues greater than 1 were analysed. RESULTS. PC1 (32.94% of variation) and PC2 (25.79% of variation) from PCA analysis and correlation matrices separated patients according to correlated clusters of established inflammatory markers of OA pain and progression (IL6/IL8, r=0.754, p<0.001) and anti-inflammatory mediators (IL4/IL10, r=0.469, p=0.005). Bone turnover marker ALP was positively associated with KL grade (r=0.815, p=0.002) and negatively associated with IL10 (r=−0.402, p=0.018) and first peak knee loading pressures (r=−0.688, p=0.019). RANKL was positively associated with IL4 (r=0.489, p=0.003). Synovial fluid Sema3A concentrations showed separate clustering from all OA progression markers and was inversely correlated with TNF-α (r=−0.423, p=0.022) in HTO patients. Sema3A was significantly inversely correlated with total predicted force in the medial joint compartment (r=−0.621, p=0.041), mean (r=−0.63, p=0.038) and maximum (r=−0.613, p=0.045) calculated medial compartment joint pressures during the first phase and mean (r=−0.618, p=0.043) and maximum (r=−0.641, p=0.034) medial compartment joint pressures during midstance outputs of patient-specific musculoskeletal model. CONCLUSIONS. This study shows joint inflammatory status and mechanical overloading influence subchondral bone-remodelling. Synovial Sema3A concentrations are inversely correlated to patient-specific musculoskeletal model estimations of pathological medial overloading. This study reveals Sema3A as a biological mediator with capacity to induce OA pain and disease progression that is directly regulated by gait mechanical loading. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Aims

Micromotion of the polyethylene (PE) inlay may contribute to backside PE wear in addition to articulate wear of total knee arthroplasty (TKA). Using radiostereometric analysis (RSA) with tantalum beads in the PE inlay, we evaluated PE micromotion and its relationship to PE wear.

Introduction and Aims: High tibial osteotomy (HTO) is a corrective surgical procedure used to treat medial compartment osteoarthritis (OA). In HTO a bone wedge is resected from the upper tibia to realign the lower limb. In this study, we investigated the effect of HTO on patellofemoral joint motion using a validated new technique. Method: We assessed patellar tracking in four subjects before and after high tibial osteotomy surgery. A high-resolution MR image was acquired of each subject’s knee. Each subject then loaded his/her knee in a custom test rig in the MR scanner, while fast, low-resolution MRI scans were acquired. This was repeated at five flexion angles. Bone outlines were identified (image segmentation) and processed (meshed) to yield bone models. Knee kinematics were determined by matching (registering) the high-resolution bone models to the low-resolution bony outlines. We compared the pre- and post-operative tracking patterns using a two-way repeated measures ANOVA. Results: The resultant patellar tracking patterns were expressed as a function of knee flexion. Mean values for each quantity were calculated over the flexion range. High tibial osteotomy decreased patellar flexion by a mean of 5.06 degrees (p < 0.003), decreased internal patellar spin by a mean of 1.25 degrees (p < 0.001) and increased medial patellar tilt by a mean of 1.59 degrees (p < 0.001). High tibial osteotomy increased proximal patellar translation by a mean of 4.19mm (p < 0.008), but, for the number of specimens tested, we found no significant change in anterior or medial translation. Conclusion: Our finding that HTO translated the patella proximally is consistent with findings of elevated patellae in the literature. The significant changes in patellar movement caused by high tibial osteotomy surgery suggest that the post-operative anterior knee pain associated with these procedures is due to mechanical changes at the patellofemoral joint

Introduction:. Patient-specific cutting guides (PSCG) built from imaging of the extremity can improve the accuracy of bone cuts during total knee replacement (TKR). Some reports have suggested that PSCG offer only marginal improvement in the accuracy of alignment and component positioning in TKA. We compared outcomes between TKRs done with PSCG versus standard, intramedullary-based instrumentation. Methods:. Blood loss, duration of surgery, alignment of the mechanical axis of the leg, and implant position on standing, long-leg, and standard lateral digital radiographs were compared between a CT-guided, custom-built TKA implant (n = 50; ConforMIS iTotal, Boston, MA) implanted with PSCG, versus an off-shelf posterior stabilized TKA implanted with standard instrumentation (n = 50; NKII total knee, Zimmer, Warsaw, IN). The fraction of outliers (>3 degrees) was calculated for the two groups. Results:. The mean mechanical axis of iTotal was 181 degrees with a fraction of outliers of 0.2, versus 178 degrees for NKII with fraction of outliers of 0.7. For frontal plane positioning of femoral components, fraction of outliers for iTotal was 0.04, versus 0.6 for NKII. For tibial components, corresponding values were 0.1 and 0.6, respectively. Sagittal plane outliers were 0.2 and 0.9, respectively, for femoral components; and 0.2 and 0.6 for tibial components. Surgery duration was 5 minutes less and blood loss was 100 mL less for iTotal than for intramedullary-aligned NKII. Conclusion:. Patient specific instrumentation and custom-built implants showed a trend toward improved accuracy of alignment, reduction in blood loss and operating time, when compared to standard, off-the-shelf TKA implants with intramedullary alignment, with fewer radiographic outliers. Larger, randomized trials are necessary to evaluate this technology further, but the initial outcomes appear favorable, with no cost disadvantage to the custom-built implant

High tibial osteotomy is a well established joint preserving procedure for the treatment of unicompartmental knee osteoarthritis. Of particular interest are the alterations in knee loading compartments during dynamic activities such as locomotion. Computer modelling can indirectly assess contact and muscle forces in the patient. This study aimed to develop a valid model representative of high tibial osteotomy to assess the medial joint contact force at the knee during gait. Software for Interactive Musculoskeletal Modelling (version 2, SIMM Inc, USA) was used to develop a model to replicate the effects of high tibial osteotomy surgery on tibial alignment. The program was then used to perform a detailed analysis on gait data collected from two high tibial osteotomy patients preoperatively and 6 months post operatively. Inverse dynamics simulations were conducted to investigate knee joint contact force on the medial compartment of the two patients during the stance phase of their operated limbs. Significant decreases (p<0.05) in the medial joint contact force were observed during both early and late stance for both patients. Force generated in muscles crossing the knee was found to be the major contributor to the joint contact force. Total muscle force was found to increase significantly (p<0.05) following surgery, however decreased loads were calculated for the medial compartment. The pattern and magnitude of joint reaction force was found to be consistent before and after surgery and replicated the results of previous studies. The HTO-specific model was valid and sensitive to changes in joint reaction force, medial joint contact force and muscle forces crossing the knee. High tibial osteotomy reduced the medial joint contact force at the knee as a result of the coronal realignment of the limb. Osteoarthritis symptoms were relieved in terms of knee pain and function. Finally, a difference in compensatory strategies was observed between patients. This novel technique allows non-invasive assessment of the mechanical effect of procedures such as HTO. This should allow more accurate planning and assessment of such surgical procedures

Improved surgical techniques and new fixation methods have revived interest in high tibial osteotomy surgery in recent years. Our aim was to review our first 59 cases. All patients underwent radiological and clinical review including pre and post operative scores. Mean age at surgery was 43 (22-59) and mean follow up is 22 months. The mean pre-operative limb alignment was 5.4° varus (range 1°-16°) with correction to 2° valgus (range -1° - 7°). HTO is known to increase tibial slope and in this series the change in tibial slope from -5.2° (95%CI: -6.36 to -4.07)) to -7.8° (-8.83 to –6.89) was statistically significant. p= 0.0014 (Mann Whitney). Patellar height is often reduced following opening wedge HTO and this is confirmed in our series. The Blackburne-Peel ratio changed from 0.74 to 0.58 and the Caton-Descamps from 0.83 to 0.7. Both were statistically significant at p<0.0001 and p=0.0001 respectively. All scores improved post operatively, the knee injury and osteoarthritis outcome (KOOS) from 48 (8-91) to 73 (27-96), the Oxford knee score (OKS) from 25 (3-47) to 37 (9-48), and the EQ5D from 189809 (11221-32333) to 14138 (11111-22233) with the EQ5D VAS improving from 58 to 75. There was no correlation between change in limb alignment, tibial slope or patellar height and any of the scores used. There were three superficial wound infections, and one non union which was treated with grafting and re fixation. Six patients have had their plate removed. Improvement in clinical scores in these patients confirms that medial opening wedge HTO is a reliable joint preserving procedure in the short term and our surgical technique is reproducible and consistent with other published series

Introduction: Treating tibial plateau fractures extreme care should be given to restore articular surface height preserving knee joint stability to be able to obtain maximal range of movement and to prevent future joint degenerative changes. Preoperative evaluation with CT and 3-D reconstruction is mandatory to understand the topography of the fracture for surgical planning. Traditional bone grafting techniques together with newer bone substitutes should be utilized in addition to ligamentotaxis when necessary. Fixation with smooth or olive wires (in occasions with washers for wider contact), sometimes augmented by screws is used with the Ilizarov external frame for stabilization avoiding extended incisions. In unstable fractures, bridging of the knee with slight distraction of the joint is provided by including the distal femur to the frame with an additional ring. Guided by these principles, complex tibial plateau fractures were treated in our department and the results are reported. Materials and Methods: Ten patients 40.6 years old on average (30–70) with Schatzker type V–VI fractures (all closed) were treated by hybrid 3 ring Ilizarov external frames alone or in combination with another procedure. Six were treated by ligamentotaxis and Ilizarov fixation alone and minimal opening for joint surface elevation when needed. The remaining 4 needed 6.5 mm canulated cancellous screw augmentation and 2 of them additional bone graft supplementation. Two patients needed extension of the frame to the femur with hinges on the center of joint rotation. All patients remain non-WB for 6 weeks and partial WB for another 6 weeks. Within 3 months the frame was removed and replaced by a brace or a cast-brace with full WB. Physiotherapy started early after the operation. Results: The results were analyzed over an average follow-up period of 22.6 months (range 3–53). All fractures healed in an average of 12 weeks. Range of motion in all patients included full extension with 90° of flexion or more. No postoperative infections, septic arthritis or neurovascular complications were reported. Pin site infection was resolved locally. One case resulted in mild valgus alignment due to osteoporotic bone (70 years old patient). Discussion: Ilizarov external fixation for complex tibial plateau fractures offers the advantage of minimal invasive interventions with a high level of functionality since the early post operative period. The combination with minimal invasive opening for joint surface elevation and additional screws or bone graft extends even more the scope of the treatment. Functional results were similar to previous reported series. The good observance of traditional tibial plateau surgery principles should guide the surgeons when using this modality of treatment for optimal results