scholarly journals Changes in the Mechanical Axis and Weight-Bearing Line of the Ankle After Varus Knee Correction

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0026
Author(s):  
Seung Yeol Lee ◽  
Soon-Sun Kwon ◽  
Kyoung Min Lee

Category: Ankle, Hindfoot Introduction/Purpose: Varus limb malalignment results in an imbalance of force transmission to the knee joint, resulting in a concentrated load in the medial compartment. A varus knee correction may affect the ankle and subtalar joint, because the weight-bearing load on the lower extremity extends from the hip to the foot. A previous study suggested that the true mechanical axis of the lower limb should be calculated with a line from the center of the femoral head to the lowest point of the calcaneus, not to the center of the tibial plafond. Therefore, we performed this study to evaluate changes in the mechanical axis and weight- bearing line of the ankle after varus knee correction. Methods: Patients with a varus knee who were followed-up after they had undergone high tibial osteotomy (HTO) or total knee replacement arthroplasty (TKA) at an age of >20 years, and who had undergone preoperative and postoperative scanogram were included in this study. The hip-knee-ankle (HKA) angle, mechanical axis, and weight-bearing line (line from the center of the femoral head to the lowest point of the calcaneus) were measured on the radiographs. The point at which the mechanical axis and weight-bearing line passed through the tibial plafond was the ankle joint axis point. The postoperative change in the ankle joint axis point on the mechanical axis and weight-bearing line according to the HKA angle correction was adjusted by multiple factors using a linear mixed model. Results: A total of 257 limbs from 198 patients were included in this study. The preoperative HKA was 7.3 ± 4.7° and corrected to 0.4 ± 3.8°. Although the ankle axis points on both axes moved laterally after HTO and TKA, the ankle joint axis of the weight- bearing line showed a significant larger lateral movement (22.5±35.7%) (Fig.) than that of the mechanical axis (15.7±16.0%) in terms of rate of change (p = 0.006). The ankle joint axis point on the weight-bearing line moved laterally by 0.9% per degree of postoperative HKA angle decrease (p < 0.001). The change in the ankle joint axis point on the mechanical axis was not statistically significant after HTO and TKA (p = 0.223). Conclusion: The mechanical axis and weight-bearing line of the ankle moved laterally after the varus knee correction. The ankle joint axis on the weight-bearing line moved laterally as the HKA angle decreased after the surgery, whereas the varus knee correction did not significantly affect the ankle joint axis on the mechanical axis. The varus knee correction might affect the subtalar joint as well as the ankle joint. Therefore, we believe that our findings warrant consideration in pre- and postoperative evaluations using the weight-bearing line of patients undergoing varus knee correction.

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002
Author(s):  
Kenneth Hunt ◽  
Richard Fuld ◽  
Judas Kelley ◽  
Nicholas Anderson ◽  
Todd Baldini

Category: Ankle Introduction/Purpose: Acute inversion ankle sprains are among the most common musculoskeletal injuries. Higher grade sprains, which include anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injury, can be particularly problematic and often require surgical repair. The implications of CFL injury on ankle instability are unclear. We aim to evaluate the impact of CFL injury on ankle stability and subtalar joint biomechanics. We hypothesized that CFL injury will result in decreased stiffness and torque, and alteration of ankle contact mechanics compared to the uninjured ankle in a cadaveric model. Methods: Twenty matched cadaveric ankles dissected of skin and subcutaneous tissue were mounted to an Instron with 20° of ankle plantar flexion and 15° of internal rotation. Intact specimens were axially loaded to body weight, then underwent inversion stress along the anatomic axis of the ankle from 0 to 20° (simulating inversion injury) for three cycles. ATFL and CFL were sequentially sectioned, and inversion testing repeated for each condition. Stiffness and change in torque were recorded using an Instron, and pressure and contact area were recorded using a calibrated Tekscan sensor system. Inversion angle of the talus and calcaneus relative to the ankle mortise were recorded using a three-dimensional motion capture system. Paired t tests were performed for inter and intra-group comparisons. Results: Stiffness and torque did not significantly decrease after sectioning of the ATFL, but did decreased significantly after sectioning of CFL. Peak pressures in the tibiotalar joint decreased significantly following CFL release compared to both the uninjured ankle and ATFL-only release. Mean contact area significantly increased following CFL release compared to both the uninjured ankle and ATFL release. There was a concentration of force in the anteromedial ankle joint during weight-bearing inversion. However, the center-of-force shifts 1.22 mm posteromedial after CFL release relative to an intact ankle. Motion capture showed a significant and sequential increase in inversion angle of both the calcaneus and talus, after release of each ligament. There was significantly more inversion in the subtalar joint than the tibiotalar joint with weight-bearing inversion. Conclusion: There is significantly lower stiffness and torque with weight-bearing inversion of the ankle joint complex following injury to both ATFL and CFL, and sequentially greater inversion of the talus and calcaneus with progressive ligament injury. This corresponds to a significant shift in the center of force in the tibiotalar joint. CFL contributes considerably to lateral ankle stability, and sprains that include CFL injury result in substantial alteration of contact mechanics at the ankle and subtalar joints. Repair of CFL may be beneficial during lateral ligament reconstruction, potentially mitigating long-term consequences (e.g., articular damage) of a loose or incompetent CFL.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Peizhao Wang ◽  
Xiao Wang ◽  
Xiaotao Shi ◽  
Honglue Tan

Objective. The purpose of this study was to evaluate the usefulness of preoperative planning of the femurofibular angle (FFA) in medial open-wedge high tibial osteotomy (OWHTO) for mild medial knee osteoarthritis. Methods. Thirty-two patients (32 knees) with mild medial knee OA were retrospectively reviewed. The patients underwent preoperative planning of the FFA for OWHTO. For preoperative planning, a full-length weight-bearing X-ray photograph of the lower limb was opened within Adobe Photoshop Software, and a targeted corrective mechanical axis line of the lower limb and its intersecting point at the lateral tibial plateau surface was drawn using rectangle selection and filling tools. A frame, which encircled the tibia and fibula, was created around the predicted osteotomy plane and then rotated until the ankle center was on the targeted mechanical axis line. Subsequently, a distal femoral condyle line and a proximal fibula axis line were drawn, and the angle between the two lines was measured and defined as the femurofibular angle (FFA). During biplane OWHTO, the preoperatively determined FFA was used to complete the correction of the mechanical axis. During follow-up, the postoperative mechanical weight-bearing line (WBL) of the lower limb, the mechanical femorotibial angle (mFTA), and the FFA were measured and compared with the preoperatively determined values. Results. The mechanical WBL shifted from a preoperative value of 25.36 ± 5.02 % to a postoperative value of 56.19 ± 0.10 % from the medial border along the mediolateral width of the tibial plateau, and it was 56.57 ± 0.08 % at the final follow-up ( P < 0.01 ). The preoperatively determined value was 56.25%, and no significant difference was found compared with postoperative week-one and final follow-up values ( P > 0.05 ). The mFTA was corrected from a preoperative varus of 4.02 ± 0.63 ° to a postoperative week-one valgus of 2.37 ± 0.28 ° , and it had a valgus of 2.48 ± 0.39 ° at the final follow-up ( P < 0.01 ). No significant difference in the valgus was found compared with the postoperative week-one, final follow-up and preoperatively determined valgus of 2.34 ± 0.26 ° ( P > 0.05 ). The postoperative week-one and final follow-up FFAs were 90.34 ± 1.53 ° and 90.33 ± 1.52 ° , respectively, and no significant difference was found compared with the preoperatively determined value of 90.12 ± 1.72 ° and the intraoperative setting value of 90.25 ± 1.67 ° ( P > 0.05 ). All corrected values were within the acceptable range of preoperative planning. Conclusion. Preoperative planning of the FFA may be useful in OWHTO for patients with mild medial knee OA. Satisfactory correction of the postoperative targeted mechanical axis line of the lower limb can be obtained.


2019 ◽  
Author(s):  
Koji Nozaka ◽  
Naohisa Miyakoshi ◽  
Takeshi Kashiwagura ◽  
Yuji Kasukawa ◽  
Hidetomo Saito ◽  
...  

Abstract Background: Advanced to end-stage ankle osteoarthritis in highly active older individuals has traditionally been treated using tibiotalar arthrodesis. With tibiotalar arthrodesis, high levels of pain-free function are possible; however, there is a loss of ankle joint movement and a risk of future arthrosis in the adjacent joints. Distraction arthroplasty is a simple method that allows joint cartilage repair; however, the results are currently mixed, with some reports showing improved pain scores and others showing no improvement. Distal tibial osteotomy (DTO) without fibular osteotomy, a type of joint preservation surgery, has garnered attention in recent years. However, to our knowledge, there are no reports on DTO with joint distraction using a circular external fixator. Therefore, the purpose of this study was to examine the effect of DTO with joint distraction using a circular external fixator on ankle osteoarthritis. Methods: A total of 21 patients with medial ankle arthritis were examined. Arthroscopic synovectomy and a microfracture procedure were performed. Subsequently, angled osteotomy and correction of the distal tibia were performed. After ankle conditions improved, stabilization of the ankle joint was performed. An external fixator was used in all patients. In addition, joint distraction of about 5.8 mm was performed. All patients were allowed full weight-bearing walking immediately after surgery. Results: The anteroposterior mortise angle during weight-bearing, lateral mortise angle during weight-bearing, and talar tilt angle and anterior translation of the talus on ankle stress radiography significantly improved (P < 0.05). In addition, signal changes on magnetic resonance imaging improved in all patients. Visual analogue scale and American Orthopedic Foot & Ankle Society scores also improved significantly (P < 0.05). No severe complications were observed. Conclusion: DTO with joint distraction may be useful for older patients with a high physical activity level as a joint-preserving surgery for medial ankle osteoarthritis. Level of evidence: Level IV, retrospective case series Key words : distal tibial osteotomy, medial ankle arthritis, joint distraction, circular external fixator


2020 ◽  
Author(s):  
Koji Nozaka ◽  
Naohisa Miyakoshi ◽  
Takeshi Kashiwagura ◽  
Yuji Kasukawa ◽  
Hidetomo Saito ◽  
...  

Abstract Background: Advanced to end-stage ankle osteoarthritis in highly active older individuals has traditionally been treated using tibiotalar arthrodesis. With tibiotalar arthrodesis, high levels of pain-free function are possible; however, there is a loss of ankle joint movement and a risk of future arthrosis in the adjacent joints. Distraction arthroplasty is a simple method that allows joint cartilage repair; however, the results are currently mixed, with some reports showing improved pain scores and others showing no improvement. Distal tibial osteotomy (DTO) without fibular osteotomy, a type of joint preservation surgery, has garnered attention in recent years. However, to our knowledge, there are no reports on DTO with joint distraction using a circular external fixator. Therefore, the purpose of this study was to examine the effect of DTO with joint distraction using a circular external fixator on ankle osteoarthritis. Methods: A total of 21 patients with medial ankle arthritis were examined. Arthroscopic synovectomy and a microfracture procedure were performed. Subsequently, angled osteotomy and correction of the distal tibia were performed. After ankle conditions improved, stabilization of the ankle joint was performed. An external fixator was used in all patients. In addition, joint distraction of about 5.8 mm was performed. All patients were allowed full weight-bearing walking immediately after surgery. Results: The anteroposterior mortise angle during weight-bearing, lateral mortise angle during weight-bearing, and talar tilt angle and anterior translation of the talus on ankle stress radiography significantly improved (P < 0.05). In addition, signal changes on magnetic resonance imaging improved in all patients. Visual analogue scale and American Orthopedic Foot & Ankle Society scores also improved significantly (P < 0.05). No severe complications were observed. Conclusion: DTO with joint distraction may be useful for older patients with a high physical activity level as a joint-preserving surgery for medial ankle osteoarthritis. Level of evidence: Level IV, retrospective case series Key words : distal tibial osteotomy, medial ankle arthritis, joint distraction, circular external fixator


2009 ◽  
Vol 30 (8) ◽  
pp. 734-740 ◽  
Author(s):  
Michal Kozanek ◽  
Harry E. Rubash ◽  
Guoan Li ◽  
Richard J. de Asla

Background: Knowledge of joint kinematics in the healthy and diseased joint may be useful if surgical techniques and joint replacement designs are to be improved. To date, little is known about the kinematics of the arthritic tibiotalar joint and its effect on the kinematics of the subtalar joint. Materials and Methods: Kinematics of the ankle joint complex (AJC) were measured in six patients with unilateral post-traumatic tibiotalar osteoarthritis in simulated heel strike, midstance and toe off weight bearing positions using magnetic resonance and dual fluoroscopic imaging techniques. The kinematic data obtained was compared to a normal cohort from a previous study. Results: From heel strike to midstance, the arthritic tibiotalar joint demonstrated 2.2 ± 5.0 degrees of dorsiflexion while in the healthy controls the tibiotalar joint plantarflexed 9.1 ± 5.3 degrees ( p < 0.01). From midstance to toe off, the subtalar joint in the arthritic group dorsiflexed 3.3 ± 4.1 degrees whereas in the control group the subtalar joint plantarflexed 8.5 ± 2.9 degrees ( p < 0.01). The subtalar joint in the arthritic group rotated externally 1.2 ± 1.0 degrees and everted 3.3 ± 6.1 degrees from midstance to toe off while in the control group 12.3 ± 8.3 degrees of internal rotation and 10.7 ± 3.8 degrees eversion ( p < 0.01 and p < 0.01, respectively) was measured. Conclusion: The current study suggests that during the stance phase of gait, subtalar joint motion in the sagittal, coronal, and transverse rotational planes tends to occur in an opposite direction in subjects with tibiotalar osteoarthritis when compared to normal ankle controls. This effectively represents a breakdown in the normal motion coupling seen in healthy ankle joints. Clinical Relevance: Knowledge of ankle kinematics of arthritic joints may be helpful when designing prostheses or in assessing the results of treatment interventions.


2005 ◽  
Vol 21 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Kristian M. O’Connor ◽  
Joseph Hamill

The ankle joint has typically been treated as a universal joint with moments calculated about orthogonal axes and the frontal plane moment generally used to represent the net muscle action about the subtalar joint. However, this joint acts about an oblique axis. The purpose of this study was to examine the differences between joint moments calculated about the orthogonal frontal plane axis and an estimated subtalar joint axis. Three-dimensional data were colected on 10 participants running at 3.6 m/s. Joint moments, power, and work were calculated about the orthogonal frontal plane axis of the foot and about an oblique axis representing the subtalar joint. Selected parameters were compared with a paired t-test (α = 0.05). The results indicated that the joint moments calculated about the two axes were characteristically different. A moment calculated about an orthogonal frontal plane axis of the foot resulted in a joint moment that was invertor in nature during the first half of stance, but evertor during the second half of stance. The subtalar joint axis moment, however, was invertor during most of the stance. These two patterns may result in qualitatively different interpretations of the muscular contributions at the ankle during the stance phase of running.


2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0001
Author(s):  
Naven Duggal ◽  
Ara Nazarian ◽  
Michael Nasr ◽  
Patrick Williamson ◽  
Stephen Okajima ◽  
...  

Category: Ankle, Basic Sciences/Biologics, Hindfoot, Biomechanics Introduction/Purpose: Orthotics are commonly prescribed by orthopaedic surgeons to address the hindfoot and midfoot deformity resulting from posterior tibial tendon dysfunction. The public however will often purchase over the counter orthotics for generalized complaints of foot pain that is not associated with any significant deformity or foot pathology. The mechanical axis of the lower limb may be altered in patients who use orthotics despite a normal foot alignment. We hypothesize that patients with normal alignment who use orthotics may adversely change ankle and subtalar joint orientation and load distribution. Methods: Five fresh frozen lower limb cadaveric specimens without known skeletal condition were used. The femoral head was potted with PMMA and TekScan pressure sensors were inserted into the ankle and subtalar joint. The specimens were placed on a custom jig, which allowed for load cell modulated loading of the leg; 75 lb load (half body weight) was applied at the femoral head while the foot was supported against a fixed plate keeping the ankle in neutral position. Testing was achieved by placing an orthotic under the medial half of the plantar talonavicular joint level. Mean pressure (MP), peak pressure (PP), contact area (CA), and center of force (COF) were measured in both the ankle and subtalar joints under three conditions; barefoot (BASE), with a 1.5 cm (ORT1) and 3 cm (ORT2) height orthotic. Each condition was tested three times per specimen. Displacement of COF was calculated relative to its location at baseline. Results: The MP, PP and CA showed a constant decrease from BASE to ORT1 and ORT2. Despite this relation, the only comparison that was significantly different was that between peak pressure values of the baseline and ORT2 conditions of the subtalar joint. The average displacement of COF from BASE was 0.14 mm and 0.42 mm medially, and 0.26 mm and 0.46 mm posteriorly at the ankle joint with ORT1 and ORT2 respectively. The average displacement of COF from BASE was 0.03 mm laterally and 0.08 mm posteriorly with ORT1, and 0.2 mm medially and 0.46 mm posteriorly with ORT2 at the subtalar joint. Conclusion: Foot deformities have an impact on the articular forces in the lower limb. Our results agree with previous studies about the role of foot deformity on the distribution of body weight forces and its consequences across the ankle and subtalar joint. Our novel study also demonstrates that orthotics and orthotics of varying sizes can change the mean pressure, peak pressure, contact area center of force in the ankle and subtalar joint. This study proves the feasibility of its design for studying intra-articular pressure changes in a lower limb cadaveric model with simulated weight bearing.


2019 ◽  
Author(s):  
Koji Nozaka ◽  
Naohisa Miyakoshi ◽  
Takeshi Kashiwagura ◽  
Yuji Kasukawa ◽  
Hidetomo Saito ◽  
...  

Abstract Background Advanced to end-stage ankle osteoarthritis in highly active older individuals has traditionally been treated using tibiotalar arthrodesis. Tibiotalar arthrodesis is possible to have high levels of pain-free function, however there is loss of ankle joint movement and a risk of arthrosis of adjacent joints in the future. Distraction arthroplasty is a simple method with a possibility of the joint cartilage repair but current results are mixed with reports of patients with better pain scores and some without any improvement. Distal tibial osteotomy (DTO) without fibular osteotomy, a type of joint preservation surgery, has garnered attention in recent years, However, as far as we know, there are no reports on DTO with joint distraction using a circular external fixator. The purpose of this study was to examine the effect of DTO with joint distraction using a circular external fixator on ankle osteoarthritis.Materials and Methods A total of 21 patients with medial ankle arthritis were examined. Arthroscopic synovectomy and a microfracture procedure were performed. Then angled osteotomy and correction of the distal tibia were performed. After ankle conditions improved, the stabilization of the ankle joint was performed. An external fixator was used in all patients. In addition, joint distraction of about 5.8 mm was performed. All patients were allowed full weight-bearing walking immediately after surgery.Results Antero-posterior mortise angle during weight-bearing, lateral mortise angle during weight-bearing, and talar tilt angle and anterior translation of the talus in ankle stress radiography significantly improved (P < 0.05). In addition, signal changes in magnetic resonance imaging (MRI) improved in all patients. Visual Analogue Scale (VAS ) and The American Orthopaedic Foot & Ankle Society (AOFAS) scores also improved significantly (P < 0.05). No severe complications were observed.Conclusion DTO with joint distraction may be useful for older patients with a high physical activity level as joint preserving surgery for medial ankle osteoarthritis.


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