Tibial Surface Research Articles

Subchondral Bone Cysts Remodel after Correction of Varus Deformity in Ankle Arthritis

Category: Ankle Arthritis; Ankle Introduction/Purpose: Subchondral bone cysts (SBCs) of the talus are frequently observed in ankle osteoarthritis (OA). It is unclear whether the cysts need an additional operation after correction of the varus deformity in ankle OA. The purpose of this study is to investigate the incidence of SBCs and the change after supramalleolar osteotomy (SMOT). Methods: Thirty-one patients treated by SMOT were retrospectively reviewed, 11 ankles with pre-operative cysts. After SMOT, the evolution of cysts was evaluated on weightbearing computerized tomography (WBCT) without management of cysts. The preoperative and postoperative tibial articular surface angle (TAS), tibio-talar surface angle (TTS), Foot and Ankle Offset (FAO), and hindfoot alignment calcaneal moment arm (HA) were compared. Results: At baseline, 11 (35.5%) of these 31 ankles had the SBCs, and the average maximum cyst volume was 65.86±60.53 mm3. By comparison with the pre and postoperative parameters, the TAS, TTS, FAO and HA were significantly corrected (P＜0.001). The number and volume of cysts were reduced dramatically (P＜0.05). Conclusion: Supramalleolar osteotomy can effectively correct the varus alignment and remodel the SBCs of talus in varus ankle arthritis. The regression of SBCs was observed after SMOT, additional intervention for the SBCs of the talus may not be necessary.

Open Reduction Internal Fixation to Fix Posterior Cruciate Ligament Tibial Avulsion

Tibial avulsion fractures of the Posterior cruciate ligament (PCL) are common; however, methods of surgical treatment are insufficiently described. PCL is the main posterior stabilizer of the knee and limits posterior tibial translation relative to the femur . In addition, the PCL serves as a central axis controlling and imparting rotational stability to the knee. Isolated tear or avulsion of the PCL can be caused by falling onto a flexed knee or by striking the flexed tibia on the dashboard during a motor vehicle accident . Isolated PCL disruption most commonly occurs as avulsion at the point of tibial insertion, as opposed to its femoral origin or as a mid-substance tear. The tibial insertion of the PCL is also more consistent than the femoral insertion. The two PCL fibre bundles insert, without anatomic separation, into the centrally-located fovea or facet on the posterior aspect of the tibia, 1-1.5 cm distal to the joint line, with the posterior horn of the medial meniscus being the anterior-most extension . Chronic disability and early degenerative changes can develop as a result of delayed diagnosis. The posteromedial knee approach is a surgical technique for treating tibial avulsion fractures of the PCL. The technique involves reinsertion and fixation of the PCL bone fragment into its anatomical bed located on the posterior tibial surface. The posteromedial knee approach is reportedly sufficient for re-establishing ligament integrity and function; however, most surgeons are not familiar with this surgical approach because it is poorly-described within the published literature.

Longitudinal observation of distal tibial degeneration in varus ankle osteoarthritis using plain radiograph

BackgroundThis study aimed to explore the natural history of distal tibial deformity in varus ankle osteoarthritis and to identify risk factors for its progression. MethodsThis retrospective longitudinal observational study included 97 ankles with moderate to severe varus ankle osteoarthritis, monitored for > 2 years. Radiographic assessments were conducted on weightbearing plain radiographs at the initial and final visit. ResultsSignificant tibial anterior surface angle reduction (p = 0.008), talus center medial migration (p = 0.038), and tibial lateral surface angle increase (p = 0.034) occurred. Multiple logistic analysis revealed an association between progression and coronal talar tilt angle at the first visit (odds ratio 1.17, p = 0.015) ConclusionThe progression of radiographic distal tibial deformity in varus ankle osteoarthritis was clarified, identifying the coronal talar tilt angle as a risk factor. Level of EvidenceLevel IV, retrospective longitudinal observation study

Optimizing Outcomes in Distal Tibial Deformity Correction: The Role of Supramalleolar Osteotomy with Computer-assisted Hexapod External Fixator.

Distal tibial deformities can significantly impact patients if left uncorrected, often leading to pain, alterations in gait, and the eventual development of post-traumatic arthritis. The criteria for surgical correction in these patients continues to be a subject of debate, while supramalleolar osteotomy (SMO) is an effective method for correcting distal tibial deformities. The purpose of this study was to evaluate and compare the clinical results of SMO using internal fixation or using computer-assisted hexapod external fixator in the treatment of distal tibial deformity. A retrospective study was conducted on 290 patients who underwent SMO between June 2015 and January 2023. Forty-four patients met the inclusion and exclusion criteria. Among the participants, 19 underwent SMO combined with a computer-assisted hexapod external fixator, while 25 received SMO with plate and screw internal fixation. The tibial anterior surface (TAS) angle, tibial lateral surface (TLS) angle, the tibiotalar (TT) angle and the talocrural (TC) angle were assessed on weight-bearing X-ray films. Functional assessments were performed according to the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. The study followed patients for an average duration of 31.7 ± 15.3 months, with a range from 12 to 67 months. Successful bone union was achieved in all cases. For patients treated with the computer-assisted hexapod external fixator, significant improvements were observed: the mean deviation in sagittal plane deformity parameters decreased from 14.3 ± 10.4 degrees preoperatively to 2.8 ± 3.8 degrees postoperatively (p < 0.05). Similarly, coronal plane deformity parameters showed a reduction from 25.9 ± 22.5 degrees preoperatively to 5.9 ± 11.0 degrees postoperatively (p < 0.05). The AOFAS ankle-hindfoot score improved markedly from 66.0 ± 14.9 to 86.1 ± 11.7 points (p < 0.05). For patients undergoing internal fixation, the absolute difference in coronal plane parameters improved from 15.4 ± 12.6 degrees preoperatively to 3.7 ± 3.4 degrees postoperatively (p < 0.05). A significant enhancement in AOFAS ankle-hindfoot score was also noted, increasing from 68.3 ± 14.3 points to 79.4 ± 13.5 points (p < 0.05). There were no significant differences in gender, side, follow-up time, postoperative deviation of deformity, pre- or postoperative AOFAS between the two groups. In conclusion, comprehensive preoperative planning of SMO combined with either internal fixation or a hexapod external fixator for treating distal tibial deformities can achieve satisfactory outcomes. The utilization of a computer-assisted hexapod external fixator facilitates a gradual and precise correction process, which proved to be an effective and relatively safe method.

Pilon fracture with central articular surface collapse treated by posterior tibial fenestration indirect reduction and compression technique: Two cases report.

Central collapsed fracture blocks traditionally require either an anteromedial or anterolateral approach for reduction. However, existing techniques face challenges such as soft tissue damage and compromised tibial strength, especially in pilon fractures with central articular surface collapse and an intact anterior cortex, as classified under 43B2.3 in the 2018 Orthopaedic Trauma Association/Association for the Study of Internal Fixation Fracture and Dislocation Classification Compendium. We address the management of pilon fractures with central articular surface collapse, focusing on 2 cases where conventional reduction techniques posed a risk to soft tissues and tibial integrity. The patients presented with pilon fractures characterized by a central articular surface collapse and an intact anterior cortex, aligning with the 43B2.3 classification. A novel approach was employed, utilizing posterior tibial fenestration and indirect reduction with compression techniques. This method leveraged the talus as a template for precise articular surface realignment. Both cases demonstrated excellent reduction of the distal tibial articular surface and achieved favorable functional recovery of the ankle, evidenced by high American Orthopedic Foot and Ankle Society Ankle Hindfoot Scale scores during the 3-year follow-up. The posterior tibial fenestration technique offers significant advantages for distal tibial pilon fracture reduction. It allows for precise articular realignment, facilitates bone grafting, and minimizes soft tissue and cortical bone disruption. This method is particularly effective for pilon fractures with an intact anterolateral cortex and central articular collapse, providing a valuable surgical alternative.

Anteromedial knee osteoarthritis (AMOA) evaluated with magnetic resonance imaging (MRI): a cohort study of 100 patients.

Magnetic resonance imaging (MRI) scans are increasingly used for knee osteoarthritis evaluation and preoperative planning before unicompartmental knee arthroplasty (UKA), and often patients already have MRI scans before their initial surgeon consultation. This highlights the need for surgeons to understand anteromedial osteoarthritis (AMOA) patterns on MRI. Hence, we aim to describe MRI findings in patients with AMOA meeting current indications for medial UKA. We analysed MRI scans from 100 knees evaluated for UKA between 2006 and 2013. Inclusion criteria comprised full-thickness medial compartment loss and intact lateral compartment joint space on preoperative radiographs. Assessment included cartilage lesions, osteophytes, meniscal damage, and anterior-cruciate ligament (ACL) status on tibial and femoral surfaces. Final decision to proceed with UKA relied on intraoperative findings, independent of MRI. Complete anteromedial tibial and femoral cartilage loss preserved posterior cartilage rims was evident in all cases. Cartilage thinning occurred in the lateral compartment in 34% of cases. While 62% displayed lateral osteophytes, only 6 exhibited small areas of full-thickness cartilage loss. ACL abnormalities varied: 27% normal, 3% ruptured, and 70% had intrasubstance high signal. Larger osteophytes in the medial (p = 0.012) and lateral (p = 0.002) intercondylar notch correlated significantly with ACL damage. All underwent medial UKA, with no evidence of areas with full lateral compartment cartilage loss intraoperatively. The MRI findings confirmed the radiographic diagnosis of bone-on-bone medial disease but highlights a range of findings in the ACL, lateral compartment, and patellofemoral joint compartment for patients who met the current x-ray and intraoperative indication for UKA. Further research is required to understand if these MRI changes will affect long-term outcomes.

Altered dynamic joint space in the lateral condyle compartment following medial unicompartmental knee arthroplasty

PurposeThe progression of osteoarthritis in lateral compartment has been identified as a primary complication in medial unicompartmental knee arthroplasty (UKA) revisions, irrespective of whether employing fixed bearing (FB) or mobile bearing (MB) designs. Compared to the previous contact point analyses, the tibiofemoral contacts during knee movements are comprehended by a more comprehensive understanding of joint spaces. This study aims to dynamically map the joint spaces in the lateral compartment during the single-leg lunge following FB and MB UKA procedures, and compare them with the respective contralateral native knees. It is hypothesized that the significant change in joint space for post-UKA compared to their native knees. MethodsTwelve patients with unilateral medial FB UKA and eleven patients with unilateral medial MB UKA were included and underwent computed tomography scans. The exclusion criteria included anterior cruciate ligament deficiency, postoperative knee pain, any postoperative complications, and musculoskeletal illnesses. A dual fluoroscopic imaging system was utilized to capture the single-leg lunge, and 2D-to-3D registration facilitated the visualization of knee motion. According to the knee motions, joint spaces on tibial and femoral surfaces in the lateral compartments of native, FB, and MB UKA knees were calculated and mapped. ResultsIn comparison to the native knees, FB UKA knees exhibited significant increases in medial, lateral, central, and posterior joint spaces in the lateral compartment (p < 0.05), while MB UKA knees showed significant increases only in central and posterior joint spaces (p < 0.05). Moreover, FB UKA demonstrated greater increases in medial, central, and posterior joint spaces compared to MB UKA. Tibial varus and valgus during lunges, as well as the Oxford Knee Score (OKS) and Hip-Knee-Ankle angle (HKA), correlated with joint spaces. ConclusionsDynamic joint space analysis provided a more comprehensive insight into contact dynamics. FB UKA led to an enlargement of joint spaces, whereas MB UKA resulted in joint spaces closer to native knees. These findings contribute to understanding potential postoperative complication in UKAs.

Critical Examination of Methods to Determine Tibiofemoral Kinematics and Tibial Contact Kinematics Based on Analysis of Fluoroscopic Images.

Goals of knee replacement surgery are to restore function and maximize implant longevity. To determine how well these goals are satisfied, tibial femoral kinematics and tibial contact kinematics are of interest. Tibiofemoral kinematics, which characterize function, is movement between the tibia and femur whereas tibial contact kinematics, which is relevant to implant wear, is movement of the location of contact by the femoral implant on the tibial articular surface. The purposes of this review article are to describe and critique relevant methods to guide correct implementation. For tibiofemoral kinematics, methods are categorized as those which determine (1) relative planar motions and (2) relative three-dimensional (3D) motions. Planar motions are determined by first finding anterior-posterior (A-P) positions of each femoral condyle relative to the tibia and tracking these positions during flexion. Of the lowest point (LP) and flexion facet center (FFC) methods, which are common, the lowest point method is preferred and the reasoning is explained. 3D motions are determined using the joint coordinate system (JCS) of Grood and Suntay. Previous applications of this JCS have resulted in motions which are largely in error due to "kinematic crosstalk." Requirements for minimizing kinematic crosstalk are outlined followed by an example, which demonstrates the method for identifying a JCS that minimizes kinematic crosstalk. Although kinematic crosstalk can be minimized, the need for a JCS to determine 3D motions is questionable based on anatomical constraints, which limit varus-valgus rotation and compression-distraction translation. Methods for analyzing tibial contact kinematics are summarized and validation of methods discussed.

Accuracy of patient-specific instrumentation for implant positioning in custom-made total ankle arthroplasty.

This retrospective radiological analysis aimed to assess the accuracy of implant positioning in patients with ankle arthritis undergoing custom-made total ankle arthroplasty (TAA) with patient-specific instrumentation (PSI) compared with preoperative planning. Patients who underwent custom-made TAA with PSI from January 2018 to March 2023 were retrospectively evaluated, focusing on the tibial anterior surface (TAS) angle, tibial lateral surface (TLS) angleand tibiotalar ratio (TTR). Additionally, data regarding the time from the preoperative computed tomography (CT) scan to surgery, associated proceduresand complications were recorded. No associated procedures were performed, and only one intraoperative complication, an iatrogenic lateral malleolar fracture, was recorded. In the coronal plane, custom-made TAA with PSI consistently achieved precise positioning of prosthetic components, even in cases with significant preoperative deformities or bone deficits. However, a statistically significant deviation from the planned values was observed in the sagittal plane (p = 0.007). A notable correlation was identified between the time elapsed from the preoperative CT scan to surgery and the deviation from the planned to the actual postoperative TAS angle (p < 0.001). This study underscores the efficacy of PSI systems in achieving precise positioning in the coronal plane, in accordance with preoperative planning. In contrast, sagittal plane positioning did not demonstrate the same level of accuracy, as evidenced by a statistically significant difference between the planned and postoperative TLS values. Nevertheless, all measurements remained within the recommended range according to the existing literature. Level IV.

Relationship between intra-operative joint gap and knee flexion angle after posterior-stabilized total knee arthroplasty

PurposeConflicting evidence exists about the appropriate intra-operative soft tissue balance in posterior-stabilized (PS) total knee arthroplasty (TKA). The purpose of this prospective observational study was to investigate the impact of intra-operative soft tissue balance on post-operative knee flexion angle. MethodsA single surgeon performed 164 TKAs using a single brand of PS prosthesis via the subvastus approach without using a pneumatic tourniquet. Intra-operative soft tissue balance was quantified as the gaps between the femoral component and tibial osteotomy surface with the knee flexed at 0°, 30°, 90°, and 120° with the patellofemoral joint reduced. Multiple regression analyses were employed to identify independent predictors of knee flexion angle 1 year after TKA. ResultThe pre-operative knee flexion angle and the gap difference between 120° and 0° flexion were positively correlated with knee flexion angle 1 year after TKA [β ​= ​0.37, 95% confidence interval (CI) 0.26–0.48, P ​< ​0.001; and β ​= ​1.09, 95% CI 0.04–2.14, P ​= ​0.042, respectively]. There was no correlation with knee flexion angle 1 year after TKA for the gap difference between 30° flexion and 0° flexion and between 90° flexion and 0° flexion. ConclusionsIntra-operative soft tissue balance at 120° flexion may affect the post-operative knee flexion angle in PS-TKA.

Influence and risk factors of lateral hinge fracture on early effectiveness of supramalleolar osteotomy

To evaluate the influence of lateral hinge fracture (LHF) on the early effectiveness of supramalleolar osteotomy (SMO) and to explore the related risk factors for LHF. A total of 39 patients (39 feet) with varus-type ankle osteoarthritis treated with SMO between January 2016 and December 2022 were analyzed retrospectively. There were 10 males and 29 females, aged from 41 to 71 years (mean, 57.7 years). According to Takakura stage, there were 6 feet in stage Ⅱ, 19 feet in stage Ⅲa, and 14 feet in stage Ⅲb. The LHF was recognized by the immediate postoperative X-ray film. The osteotomy healing time and the changes of pain visual analogue scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, tibial anterior surface angle (TAS), tibial lateral surface angle (TLS), and tibiotalar angle (TT) before and after operation were compared between patients with and without LHF. The age, gender, affected side, body mass index, Takakura stage, preoperative VAS score, preoperative AOFAS score, preoperative TAS, preoperative TLS, preoperative TT, SMO correction angle, osteotomy distraction, distance from medial osteotomy to ankle joint line (MD), and distance from lateral osteotomy to ankle joint line (LD) were compared between with and without LHF patients, and further logistic regression analysis was used to screen the risk factors of LHF during SMO. All patients were followed up 12-54 months (mean, 27.1 months). During operation, 13 feet developed LHF (group A) and 26 feet did not develop LHF (group B). X-ray film reexamination showed that 1 patient in group A complicated with tibial articular surface cleft fracture had delayed osteotomy and healed successfully after plaster fixation; the osteotomy of other patients healed, and there was no significant difference in healing time between the two groups ( P>0.05). At last follow-up, there were significant differences in VAS score, AOFAS score, TAS, TLS, and TT of the two groups when compared with preoperative ones ( P<0.05), but there was no significant difference in the changes of above indicators before and after operation between the two groups ( P>0.05). The differences in SMO correction angle, osteotomy distraction, and LD between with and without LHF patients were significant ( P<0.05), and further logistic regression analysis showed that excessive LD was the risk factor of LHF during SMO ( P<0.05). Too high or too low lateral hinge position during SMO may lead to LHF, but as long as appropriate treatment and rehabilitation measurements are taken, the early effectiveness is similar to that of patients without LHF.

Degradation of Proteoglycans and Collagen in Equine Meniscal Tissues.

Investigate meniscal extracellular matrix degradation. Equine menisci (n = 34 from 17 horses) were studied. Site-matched sections were cut and scored from three regions (ROIs; n = 102) and stained for histology, proteoglycan (safranin O and fast green), aggrecan, and collagen cleavage (NITEGE, DIPEN, and C1,2C antibodies, respectively). Picrosirius red and second harmonic generation microscopy were performed to investigate collagen ultrastructure. A total of 42 ROIs met the inclusion criteria and were included in the final analysis. The median (range) ROI histological score was 3 (0-9), providing a large spectrum of pathology. The median (range) proteoglycan score was 1 (0-3), representing superficial and central meniscal loss. The median (range) of DIPEN, NITEGE, and C1,2C scores was 1 (0-3), revealing immunostaining of the femoral and tibial surfaces. The proteoglycan scores exhibited significant positive associations with both histologic evaluation (p = 0.03) and DIPEN scores (p = 0.02). Additionally, a robust positive association (p = 0.007) was observed between the two aggrecanolysis indicators, NITEGE and DIPEN scores. A negative association (p = 0.008) was identified between NITEGE and histological scores. The C1,2C scores were not associated with any other scores. Picrosirius red and second harmonic generation microscopy (SHGM) illustrated the loss of the collagen matrix and structure centrally. Proteoglycan and collagen degradation commonly occur superficially in menisci and less frequently centrally. The identification of central meniscal proteoglycan and collagen degradation provides novel insight into central meniscal degeneration. However, further research is needed to elucidate the etiology and sequence of degradative events.

Anatomical factors in the development of medial-sided osteochondral lesion of the talus: a comparative analysis.

The aim of this study was to determine anatomical predictors for the occurrence of medial osteochondral lesions of the talus (OLT), by analyzing morphometric variables obtained from magnetic resonance imaging (MRI). A total of 430 ankles with 215 ankle MRIs from patients with nontraumatic OLTs on the medial side of the talar dome and an equal number of age, sex, and side-matched healthy controls were analyzed in this retrospective study. The specific MRI parameters that were measured include the anterior opening angle of the talus (AOT), the angle between the tibial axis and medial malleolus (TMM), the angle of the tibial plafond to the malleoli (PMA), the angle between the anterior and posterior talofibular ligaments (ATFL-PTFL angle), length of the trochlea tali arc (TAL), sagittal length of distal tibial articular surface (TAS), the ratio of the sagittal length of distal tibial articular surface to the length of the trochlea tali arc (TAS/TAL), and the depth of the incisura fibularis (IncDep). AOT, IncDep, ATFL-PTFL angle, PMA, TMM, TAL, and TAS/TAL exhibited significant differences between the two groups. The established cut-off values were 13° (AUC 0.875) for AOT, 3.7mm (AUC 0.565) for IncDep, 78° (AUC 0.729) for ATFL-PTFL angle, 14° (AUC 0.581) for PMA, 15° (AUC 0.907) for TMM, 34.3mm (AUC 0.599) for TAL, and 0.81 (AUC 0.719) for TAS/TAL. Multivariate logistic regression analysis revealed Odds Ratio (OR) = 22.22 for AOT > 13°, OR = 4.23 for ATFL-PTFL angle > 78°, OR = 1.99 for PMA ≤ 14°, OR = 31.598 for TMM > 15°, OR = 3.79 for TAS/TAL ≤ 0.81. This study highlights the significance of anatomical parameters, particularly the TMM and AOT, as key predictors of OLT.

Optimizing Socket-Tunnel Position for Meniscal Allograft Transplantation Combined With ACL Reconstruction: A 3D Model Analysis

Background: Socket-tunnel overlap during meniscal allograft transplantation (MAT) combined with anterior cruciate ligament reconstruction (ACLR) may compromise graft integrity and lead to impaired fixation and treatment failure. Purpose/Hypothesis: The purpose of this study was to determine optimal socket-tunnel drilling parameters for medial and lateral MAT with concurrent ACLR using artificial tibias and computed tomography (CT) scans for 3-dimensional (3D) modeling. It was hypothesized that clinically relevant socket tunnels could be created to allow for concurrent medial or lateral MAT and ACLR without significant risk for overlap at varying tunnel guide angles. Study Design: Descriptive laboratory study. Methods: A total of 27 artificial right tibias (3 per subgroup) were allocated to 9 experimental groups based on the inclination of the socket tunnels (55°, 60°, and 65°) created for simulating medial and lateral MAT and ACLR. Five standardized socket tunnels were created for each tibia using arthroscopic guides: one for the ACL tibial insertion and one for each meniscus root insertion. CT scans were performed for all specimens and sequentially processed using computer software to produce 3D models for quantitative assessment of socket-tunnel overlap risk. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests. Results: No subgroup consistently presented significantly safer distances than other subgroups for all distances measured. Three cases (11%) and 24 cases (~90%) of tunnel overlap occurred between the ACL tunnel and tunnels for medial and lateral MAT, respectively. Most socket-tunnel overlap (25 of 27; 92.6%) occurred between sockets at depths ranging between 6.3 and 10 mm from the articular surface. For ACLR and posterior root of the lateral meniscus setting, the guide set at 65° increased socket-tunnel distances. Conclusion: When combined ACLR and MAT using socket tunnels for graft fixation is performed, the highest risk for tibial socket-tunnel overlap involves the ACLR tibial socket and the lateral meniscus anterior root socket at a depth of 6 to 10 mm from the tibial articular surface. Clinical Relevance: Setting tibial guides at 65° to the tibial articular surface with the tunnel entry point anteromedial and socket aperture location within the designated anatomic “footprint” will minimize the risk for socket-tunnel overlap.

Bosworth ankle fracture-dislocation: current concept review.

Bosworth fracture (BF) is a special type of locked ankle fracture-dislocation, characterized by displacement of a fragment of the fractured fibula from the fibular notch behind the posterior surface of the distal tibia. BF is a complex injury affecting multiple structures of the ankle joint, which is still frequently misjudged even today, potentially leading to severe complications. CT examination, including 3D reconstructions, should be the diagnostic standard in BF, as it provides a complete picture of the fracture pathoanatomy, most prominently the morphology of the frequently associated posterior malleolar fracture. BF requires early reduction of the displaced fibular fragment without repeated attempts on closed reduction. Non-operative treatment of BF almost always fails. The standard treatment procedure is early open reduction internal fixation. Due to the relative severity and paucity of the injury, BF seems to be particularly prone to soft tissue complications, including compartment syndrome. The results of operative treatment are mixed. Many studies report persistent pain even after a short time interval, with limitations of the range of motion or even stiffness of the ankle joint, and development of degenerative changes. Larger studies with long-term results are still missing.

MR imaging methods to study meniscal position and mechanics

ObjectiveMeniscal mechanics have been studied widely due to the high prevalence of meniscal injuries and their strong association with knee degeneration. Computational models and cadaver studies have contributed to our understanding of the menisci but require assumptions to extrapolate to living people. Imaging modalities provide the ability to make key measurements in vivo. In particular, magnetic resonance imaging (MRI) provides the three-dimensional (3D) visualization of the menisci required to make important measurements related to mechanical function. This mini review summarizes MR approaches that have been used to make measurements related to meniscal mechanics, including morphology, position, movement, shape, and extrusion. DesignA literature search was performed using PubMed and Google Scholar, with search terms including “meniscus” and “MRI” in combination with “mechanics”, “position”, “shape”, “movement”, “size”, “loaded”, and “unloaded”. Articles were manually reviewed and selected by consensus between the authors as constituting the most important examples of work required to illustrate the breadth of measurement and imaging approaches used in research on meniscal function. ResultsMRI has been used for quantitative 3D analyses of the morphology and position of the menisci. Morphological analyses included measurements of meniscal volume, thickness, width, and bulging. Positional analyses included measurements of the overlap between the meniscal surface and tibial joint surface, the amount of extrusion, and the percentage of joint surface area and meniscal area that were covered or uncovered. Open MR scanners have been used to measure the movement of the menisci from full extension to deep flexion. MR compatible loading devices have been used to study the effect of loading on meniscal morphology and extrusion. Studies using these methods have found that there are differences in meniscal morphology between healthy and osteoarthritic participants, that the lateral meniscus and anterior horns have greater movement throughout flexion, and that meniscal extrusion increases under load. ConclusionsMRI has improved our insight into meniscal mechanics. Simulated weightbearing, open imaging through the range of knee flexion, and image processing to yield 3D measurements have all contributed to this progress. These approaches have strong potential to explore clinically motivated research questions related to meniscal mechanics.

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

BackgroundSolely 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. MethodsSeventy 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. ResultsΔTTS 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. ConclusionSolely 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.

Tibiofemoral articulation and axial tibial rotation of the knee after a cruciate retaining total knee arthroplasty

PurposeNumerous research has reported that total knee arthroplasty (TKA) cannot reproduce axial tibial rotations of normal knees. The objective of this study was to measure the tibiofemoral articular contact motions and axial tibial rotations of TKA knees to investigate the mechanism causing the knee kinematics change of after TKAs.MethodsEleven patients with unilateral cruciate retaining (CR) TKA were tested for measurements of knee motion during a weight-bearing flexion from 0° to 105° using an imaging technique. The tibiofemoral contact kinematics were determined using the contact points on medial and lateral surfaces of the tibia and femoral condyles. Axial tibial rotations were calculated using the differences between the medial and lateral articulation distances on the femoral condyles and tibial surfaces at each flexion interval of 15°.ResultsOn femoral condyles, articular contact distances are consistently longer on the medial than on the lateral sides (p < 0.05) up to 60° of flexion, corresponding to internal tibial rotations (e.g., 1.3° ± 1.0° at 15–30° interval). On tibial surfaces, the articular contact point on the medial side moved more posteriorly than on the lateral side at low flexion angles, corresponding to external tibial rotations (e.g., −1.4° ± 1.8° at 15–30° interval); and more anteriorly than on the lateral sides at mid-range flexion, corresponding to internal tibial rotations (e.g., 0.8° ± 1.7° at 45–60° interval). At higher flexion, articular motions on both femoral condyles and tibial surfaces caused minimal changes in tibial rotations.ConclusionsThese results indicate that the axial tibial rotations of these TKA knees were mainly attributed to asymmetric articulations on the medial and lateral femoral condyles and tibial surfaces. The data can help understand the mechanisms causing axial tibial rotations of TKA knees and help improve implant designs for restoration of normal knee kinematics.

Advancing treatment strategies for posterior malleolar malunion: The ankle dislocation method

BackgroundThis study aimed to assess the radiological and clinical outcomes of treatment using the ankle dislocation method for posterior malleolar malunion. MethodThirty-one patients with posterior malleolar malunion who underwent treatment using the ankle dislocation method from May 2015 to October 2021 were retrospectively analyzed. Key outcome measures were radiographic parameters (articular step-off, tibiofibular clear space, fibular length, tibial lateral surface angle, and ankle osteoarthritis), clinical scores (American Orthopaedic Foot and Ankle Society ankle-hindfoot scale and Visual Analogue Scale), and patient satisfaction rate. ResultPreoperative computed tomography revealed that Bartoní ček types 3 and 4 accounted for 64.5 % (n = 20) of total cases. Most posterior malleolar malunions were accompanied by depressed intercalary fragments (61.2 % [n = 19]). At the final follow-up, radiographic parameters and clinical scores showed significant improvements postoperatively (P < 0.05), with a high patient satisfaction rate of 77.4 %. Subgroup analysis revealed that the posterior malleolar fracture morphology significantly affected postoperative pain, particularly in more complex fractures (P < 0.001). ConclusionThe ankle dislocation method effectively exposes the distal tibial articular surface and facilitates the anatomical restoration of joint congruity under direct vision. This approach substantially improves the clinical and imaging outcomes in patients with complex posterior malleolar malunion. Levels of EvidenceLevel IV, retrospective case series.

Arthroscopic Medial Meniscal Root Repair Using a Novel Re-Tensionable All-Suture Anchor

Background: Medial meniscal root repairs are devastating injuries that can cause long-term knee problems if not properly addressed. Some common issues when addressing these injuries surgically include the “bungee-cord” effect seen with implants that sit too far from the tibial plateau surface and loss of tension on the sutures after cycling of the knee after the repair. This video will discuss the presentation of a patient with a medial meniscal root repair treated with a novel technique to counteract these aforementioned issues. Indications: Based on the patient’s medial meniscal root tear and minimal arthritis seen on radiograph, he was indicated for a meniscal root repair to prevent meniscal extrusion and reinforce normal meniscal hoop stresses to limit progression of his arthritis. Technique Description: This technique uses a novel re-tensionable all-suture anchor through a transtibial tunnel with 2 repair sutures through the meniscal root that sits just below the tibial plateau, allowing the surgeon the ability to re-tension the implant after cycling the knee. Results: Arthroscopic repair of the medial meniscal root allowed the patient to return to his previous level of activity. Discussion/Conclusion: In this case, arthroscopic medial meniscal root repair can yield good results in patients to get them back to their previous level of activity while minimizing the chance of rapid arthritic progression that is typically seen with nonoperative management of these injuries. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.