Changes in Relative Work of the Lower Extremity and Distal Foot Joints After Total Ankle Replacement: An Exploratory Study.

Ankle osteoarthritis does not only led to lower ankle power generation, but also results in compensatory gait mechanics at the hip and Chopart joints. Much of previous work explored the relative work distribution after total ankle replacement (TAR) either across the lower extremity joints where the foot was modelled as a single rigid unit or across the intrinsic foot joints without considering the more proximal lower limb joints. Therefore, this study aims, for the first time, to combine 3D kinetic lower limb and foot models together to assess changes in the relative joint work distribution across the foot and lower limb joints during level walking before and after patients undergo TAR. We included both patients and healthy control subjects. All patients underwent a three-dimensional gait analysis before and after surgery. Kinetic lower limb and multi-segment foot models were used to quantify all inter-segmental joint works and their relative contributions to the total lower limb work. Patients demonstrated a significant increase in the relative ankle positive joint work contribution and a significant decrease in the relative Chopart positive joint work contribution after TAR. Furthermore, there exists a large effect toward decreases in the relative contribution of the hip negative joint work after TAR. In conclusion, this study seems to corroborate the theoretical rationale that TAR reduces the compensatory strategy in the Chopart and hip joints in patients suffering from end-stage ankle osteoarthritis.

Cruciate-substituting and posterior-stabilised total knee arthroplasties had similar gait patterns in the short term.

PURPOSE: Surgeons want to achieve native kinematics in primary total knee arthroplasty (TKA). Cruciate-substituting (CS) implants could restore the knee kinematics more efficiently than posterior-stabilised (PS) TKA. This study aimed to compare gait patterns in patients with CS or PS TKA at 6 months. The hypothesis was that CS implants would demonstrate comparable gait parameters to PS implants at 6 months. METHODS: In this prospective case-control study, 38 primary TKA without coronal laxity were divided into 2 groups: 19 cruciate-substituting (CS) and 19 posterior-stabilised (PS) implants. The type of prosthesis was determined according to the surgical period. Exclusion criteria were TKA revision, associated procedures and inability to walk on a treadmill. Gait analysis was conducted on a treadmill 6 months postoperatively for each patient with a knee assessment device (KneeKG®). Gait characteristics included analysis in three spatial dimensions (flexion-extension, abduction-adduction, internal-external rotation, anterior-posterior translation). Clinical outcomes (Knee Society Score and Forgotten Joint Score) were compared between both groups at 6 months postoperatively. RESULTS: At 6 months, the gait analysis did not demonstrate any significant difference between CS and PS implants. The range and the maximum anteroposterior translation were similar in both groups (9.2 ± 6.5 mm in CS group vs. 8.1 ± 3 mm in PS group (n.s.); and - 5.2 ± 5 mm in CS group vs. - 6.3 ± 5.9 mm in PS group (n.s.), respectively). The internal/external rotation, the flexion, and the varus angle were similar between CS and PS implants. The KSS Knee score was higher at 6 months in the CS group than in the PS group (92.1 ± 5.6 vs. 84.8 ± 8.9 (p < 0.01)). CONCLUSION: Cruciate-substituting and posterior-stabilised TKA had similar gait patterns at 6 months postoperatively, despite a non-equivalent posterior stabilisation system. CS prostheses were an interesting option for primary TKA for knee kinematics restoration without requiring a femoral box. LEVEL OF EVIDENCE: Prospective, case-control study; Level II.

Concomitant Triceps Surae Lengthening in Total Ankle Arthroplasty Affects the Mechanical Work at the Ankle Joint.

BACKGROUND: Previous studies have examined the effect of concomitant triceps surae lengthening on ankle dorsiflexion motion at the time of total ankle arthroplasty (TAA). As plantarflexor muscle-tendon structures are important for producing positive ankle work during the propulsive phase of gait, caution should be exercised when lengthening triceps surae, as it may decrease plantarflexion strength. In order to develop an understanding of the work of the anatomical structures crossing the ankle during propulsion, joint work must be measured. The aim of this explorative study was to assess the effect of concomitant triceps surae lengthening with TAA on the resultant ankle joint work. METHODS: Thirty-three patients were recruited to the study and divided into 3 groups of 11. The first group underwent both triceps surae lengthening (Strayer and TendoAchilles) and TAA (Achilles group), the second group underwent only TAA (Non-Achilles group), and the third group underwent only TAA, but had a greater radiographic prosthesis range of motion (Control group) compared to the first 2 groups. The 3 groups were matched in terms of demographic variables and walking speed. All patients underwent a 3D gait analysis 1 year after surgery to measure intersegmental joint work using a 4-segmented kinetic foot model. An analysis of variance (ANOVA) or Kruskal-Wallis test was used to compare the 3 groups. RESULTS: The ANOVA showed significant differences between the 3 groups. Post hoc analyses suggested that (1) the Achilles group had less positive work at the ankle joint than the Non-Achilles and Control groups; (2) the Achilles group produced less positive work performed by all foot and ankle joints than the Control group; and (3) the Achilles and Non-Achilles groups absorbed less energy across all foot and ankle joints during the stance phase than the Control group. CONCLUSION: Concomitant triceps surae lengthening in TAA may reduce the positive work at the ankle joint. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

GNRB® laximeter with magnetic resonance imaging in clinical practice for complete and partial anterior cruciate ligament tears detection: A prospective diagnostic study with arthroscopic validation on 214 patients.

BACKGROUND: Accurate diagnosis of anterior cruciate ligament (ACL) injury is not always obtained with magnetic resonance imaging (MRI). Other tools, such as the GNRB® arthrometer, help to accurately identify the type of ACL tear. The aim of this study was to show that the GNRB® could be a relevant complementary solution to MRI in ACL injuries detection. METHODS: A prospective study performed between 2016 and 2020 included 214 patients who had undergone knee surgery. The study compared sensitivity/specificity pairs of MRI and the GNRB® at 134 N to detect healthy ACL, partial and complete ACL tears. Arthroscopies were the 'gold standard'. Forty-six patients had a healthy ACL with associated knee lesions, 168 patients had ACL tears where 107 were complete tears and 61 were partial tears. RESULTS: For healthy ACL, MRI scored 100% for sensitivity (SE) and 95% for specificity (SP), and the GNRB® scored SE 95.65% and SP 97.5% at 134 N. For complete ACL tears, MRI scored 80.81% for sensitivity (SE) and 64.49% for specificity (SP), and the GNRB® scored SE 77.78% and SP 85.98% at 134 N. For partial tears, MRI scored SE 29.51% and SP 88.97%, and the GNRB® scored SE 73.77% and SP 85.52% at 134 N. CONCLUSION: GNRB® sensitivity and specificity were equivalent to those of MRI for healthy ACL and complete ACL tear detection. However, MRI had some difficulty in detecting partial ACL tears compared with the GNRB® which showed better sensitivity.

No difference of gait parameters in patients with image-free robotic-assisted medial unicompartmental knee arthroplasty compared to a conventional technique: early results of a randomized controlled trial.

PURPOSE: In recent studies, robotic-assisted surgical techniques for unicompartmental knee arthroplasty (UKA) have demonstrated superior implant positioning and limb alignment compared to a conventional technique. However, the impact of the robotic-assisted technique on clinical and functional outcomes is less clear. The aim of this study was to compare the gait parameters of UKA performed with conventional and image-free robotic-assisted techniques. METHODS: This prospective, single-center study included 66 medial UKA, randomized to a robotic-assisted (n = 33) or conventional technique (n = 33). Gait knee kinematics was assessed on a treadmill at 6 months to identify changes in gait characteristics (walking speed, each degree-of-freedom: flexion-extension, abduction-adduction, internal-external rotation, and anterior-posterior displacement). Clinical results were assessed at 6 months using the IKS score and the Forgotten Joint Score. Implants position was assessed on post-operative radiographs. RESULTS: Post-operatively, the whole gait cycle was not significantly different between groups. In both groups, there was a significant improvement in varus deformity between the pre- and post-operative gait cycle. There was no significant difference between the two groups in clinical scores, implant position, revision, and complication rates. CONCLUSION: No difference of gait parameters could be identified between medial UKA performed with image-free robotic-assisted technique or with conventional technique. LEVEL OF EVIDENCE: Prospective randomized controlled trial.

Decreased Mechanical Work Demand in the Chopart Joint After Total Ankle Replacement.

BACKGROUND: The success of total ankle replacement (TAR) must be based on restoring reasonable mechanical balance with anatomical structures that can produce mechanical joint work through elastic (eg, tendons, fascia) or viscoelastic (eg, heel pad) mechanisms, or by active muscle contractions. Yet, quantifying the work distribution across the affected joint and the neighboring foot joints after TAR is lacking. Therefore, the objective of this study was to investigate if there is a change in the joint work distribution across the Ankle, Chopart, Lisfranc and Metatarsophalangeal joints during level walking before and after patients undergo TAR. METHODS: Fifteen patients with end-stage ankle osteoarthritis scheduled for primary TAR for pain relief were recruited and peer-matched with a sample of 15 control subjects. All patients underwent a 3D gait analysis before and after surgery, during which a kinetic multisegment foot model was used to quantify intersegmental joint work. RESULTS: The contribution of the Ankle joint (P = .007) to the total foot and ankle positive work increased significantly after TAR. In contrast, a significant decrease in the contribution to the total foot and ankle joint positive work (P < .001) were found at the Chopart joint after TAR. The foot joints combined produced a significant increase in a net mechanical work from +0.01 J/kg before surgery to +0.05 J/kg after TAR (P = .006). CONCLUSION: The findings of this study corroborate the theoretical rationale that TAR reduces significantly the compensatory strategy in the Chopart joint in patients with end-stage ankle osteoarthritis after TAR. However, the findings also showed that the contribution of the ankle joint of patients after TAR to the total foot and ankle joint positive work remained impaired compared to the control group.

Patients' point of view on the long-term results of total ankle arthroplasty, tibiotalar and tibiotalocalcaneal arthrodeses.

INTRODUCTION: Total ankle arthroplasty (TAA), tibiotalar (TT) arthrodesis and tibiotalocalcaneal (TTC) arthrodesis are common surgical procedures that are sometimes concurrent. The functional results of TTC are deemed to be inferior because of the double joint sacrifice. Patient-Reported Outcome Measures (PROMs), as well as satisfaction scores, are commonly used to assess the outcome of these surgeries, but lack at capturing patients' ability to cope with potential functional limitations. The objective of our study was to compare the results of TAA, TT and TTC arthrodeses according to patients' point of view. We proposed two hypotheses: 1) TAA confer better results than TT arthrodeses, 2) and TT arthrodeses confer better results than TTC arthrodeses, on this specific criterion. MATERIAL AND METHODS: We carried out a retrospective study integrating all TAA, TT and TTC arthrodeses performed in our center from 2010 to 2017. These surgeries were compared using PROMs (Foot Function Index (FFI), Foot and Ankle Outcome Scale (FAOS) and 12-Item Short Form Survey (SF-12)), a satisfaction rating and self-reported perceived recovery state. RESULTS: Fifty-one patients were included in the TAA group, 50 in the TT group and 51 in the TTC group. The mean duration of follow-up was 46±20.8 months. The TAA group had better results than the TT group regarding the FFI score and satisfaction, thus confirming our primary hypothesis. On the other hand, no significant difference was found between the TT group and the TTC group, which invalidated our secondary hypothesis. No significant difference between the groups was found regarding the distribution of patients' perceived recovery state. CONCLUSION: Our hypothesis was not confirmed. In fact, TAAs, TT and TTC arthrodeses presented substantially similar results. Although it is difficult to compare surgeries with different indications, it is surprising to find that the patients' perceived recovery state, deviating from the usual clinical and radiological results, are relatively similar. LEVEL OF EVIDENCE: IV; Retrospective study.

Changes in ankle and foot kinematic after fixed-bearing total ankle replacement.

Ankle osteoarthritis is a chronic debilitating disease marked by cartilage breakdown, pain and significant biomechanical impairment of the entire lower limb. Total ankle replacement (TAR) has been encouraged during the last decade as it has the potential to maintain the existing pre-operative ankle range of motion and to protect the more distally located joints of the foot. Three-dimensional gait analysis using a multi-segment foot model can provide an objective analysis of TAR for the treatment of end-stage ankle osteoarthritis. Thirty-six patients suffering from post-traumatic end-stage ankle osteoarthritis were evaluated before and after TAR. A four-segment kinematic foot model was used to calculate intrinsic foot joint kinematics during gait. Spatio-temporal parameters were also assessed. Kinematic results were compared to a control group of asymptomatic subjects. Differences in waveform patterns were mainly limited to dorsi-/plantarflexion inter-segment angles. At loading response, the Shank-Calcaneus plantarflexion angles as well as the Calcaneus-Midfoot dorsiflexion angle increased slightly in post-operative condition. During propulsion, an increase in Hallux-Metatarsus dorsiflexion angle was observed. Pain improved after surgery as supported by increased spatio-temporal parameters. While multi-segment foot and ankle kinematics were improved, they remained impaired compared to control values. This study confirms that TAR maintains the residual pre-operative range of motion after surgery from midstance to propulsion. Furthermore, the results suggest that the kinematic behavior of the foot joints distal to the affected ankle joint also improves post-operatively. The outcome of this study further emphasizes the clinical relevance of multi-segment foot modeling when assessing the outcome of TAR.

Primary osteoarthritic knees have more varus coronal alignment of the femur compared to young non-arthritic knees in a large cohort study.

PURPOSE: Many surgeons are performing total knee arthroplasty (TKA) with an aim to reproducing native anatomical coronal alignment. Yet, it remains unclear if primary osteoarthritic and non-osteoarthritic populations have similar knee coronal alignment. This study aims to describe and compare the distribution of femoral and tibial coronal alignment in a large primary osteoarthritic cohort and a young non-osteoarthritic cohort. METHODS: This is a retrospective analysis of a monocentric prospectively gathered data, from 1990 to 2019, of 2859 consecutive primary osteoarthritic knees in 2279 patients. Patients underwent standardized long-leg radiographs. Femoral mechanical angle (FMA) and tibial mechanical angle (TMA) were digitally measured using software. Femoral, tibial and knee phenotypes were analyzed, and descriptive data were reported. Data were compared to a young non-osteoarthritic population previously described. RESULTS: In osteoarthritic knees, the mean FMA was 91° ± 2.9° (range 86°-100°) and the mean TMA was 87° ± 3.1° (range 80°-94°). No significant difference was observed for FMA and TMA between genders. The most common femoral and tibial phenotypes were varus (38.7%) and neutral (37.1%). The most frequent knee phenotype was a varus femoral phenotype with a neutral tibial phenotype (15.5%), which is different to the non-osteoarthritic population. CONCLUSION: This study showed the wide distribution of knee phenotypes in a large osteoarthritic cohort. There was more varus distribution of the femoral coronal alignment compared to a non-osteoarthritic population, suggesting consideration and potential adaptation of the realignment strategy of the femoral component during TKA. LEVEL OF EVIDENCE: III.

Mechanical alignment for primary TKA may change both knee phenotype and joint line obliquity without influencing clinical outcomes: a study comparing restored and unrestored joint line obliquity.

PURPOSE: In total knee arthroplasty (TKA), knee phenotypes including joint line obliquity are of interest regarding surgical realignment strategies. The hypothesis of this study is that better clinical results, including decreased postoperative knee pain, will be observed for patients with a restored knee phenotype. METHODS: A retrospective analysis was performed on prospective data, including 1078 primary osteoarthritic knees in 936 patients. The male:female ratio was 780:298, mean age at surgery was 71.3 years ± 8.0. International Knee Society Scores and standardized long-leg radiographs (LLR) were collected preoperatively and at 2 years follow-up after TKA. Patients were categorized using the Coronal Plane Alignment of the Knee (CPAK) classification including the lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) measured on LLR by a single observer, allowing knee phenotypes to be categorized considering the arithmetic hip-knee-ankle (aHKA) angle (MPTA-LDFA) as measure of constitutional alignment, and joint line obliquity (JLO) (MPTA + LDFA). Clinical results were compared between patients with surgically restored preoperative constitutional knee phenotype to patients without restored constitutional knee phenotypes. Descriptive data analysis such as means, standard deviations and ranges were performed. T tests for independent samples were performed to compare group differences. Comparisons of categorical data were performed using the χ2 test. Significance was set at p < 0.05. RESULTS: A third of patients (33.4%) had constitutional knee varus with apex distal JLO. 63.5% of patients had preoperative apex distal JLO. Postoperatively, 57.8% of patients had a neutral HKA (- 2° to 2°) and a neutral JLO (- 3° and 3°), with only 18% of patients with restored constitutional knee phenotype. Of these patients, statistically less postoperative pain was observed in patients where apex distal JLO was restored compared to non-restored apex distal JLO (pain score 46.7 vs. 44.6; p = 0.02) without clinical relevance. Other categories of restored JLO or arithmetic HKA angle were not associated with improved outcomes. CONCLUSION: This study showed that performing mechanical alignment for primary TKA resulted in most cases in a change of the preoperative knee phenotype. These results emphasize the relevance of considering joint line obliquity to better understand preoperative knee deformity and better restore knee phenotypes with a more personalized realignment strategy to potentially improve TKA postoperative results. LEVEL OF EVIDENCE: III.

Femorotibial alignment measured during robotic assisted knee surgery is reliable: radiologic and gait analysis.

PURPOSE: Femorotibial alignment is crucial for the outcome of unicompartmental knee arthroplasty (UKA). Robotic-assisted systems are useful to increase the accuracy of alignment in UKA. However, no study has assessed if the femorotibial alignment measured by the image-free robotic system is reliable. The aim of this study was to determine whether measurement of the mechanical femorotibial axis (mFTA) in the coronal plane with handheld robotic assistance during surgery is equivalent to a static measurement on radiographs and to a dynamic measurement during walking. METHODS: Twenty patients scheduled for robotic-assisted medial UKA using handheld technology were included in this prospective study. Three measurements of the frontal femorotibial axis were compared: intra-operative acquisition by computer assistance (dynamic, non-weightbearing position), radiographic measurements on long leg X-ray (static, weightbearing position), and by gait analysis during walking (dynamic, weightbearing position). RESULTS: There was no significant difference in the mFTA between computer (174.4 ± 3.4°), radiological (173.9 ± 3.3°), and gait analysis (172.9 ± 5.1°) measurements (p = 0.5). There was a strong positive correlation (r = 0.6577355, p = 0.0016) between robotic-assisted measurements and gait analysis. CONCLUSION: There was no significant difference in the femorotibial axis measured by the image-free robotic assistance, from the preoperative radiographs or by gait analysis. The reliability of intra-operative measurements of the frontal femorotibial axis by these robotic-assisted systems is acceptable.

Does a third condyle TKA restore normal gait kinematics in varus knees? In vivo knee kinematic analysis.

INTRODUCTION: Patients with knee osteoarthritis tend to modify spatial and temporal parameters during walking to reduce the pain. Total knee arthroplasty (TKA) is considered the gold standard treatment for end-stage knee osteoarthritis. However, reduced physical function of the knee is partly, but apparently not fully, remedied by surgery. The purpose of this study was to investigate the in vivo, three dimensional knee kinematics during gait at the patients with knee osteoarthritis and the influence of "third condyle" psoterior stabilized (PS) total knee arthroplasty on restoration of normal kinematics. MATERIALS AND METHODS: Twenty patients with medial knee osteoarthritis and a control group with age-matched subjects were prospectively collected for this study. The same group of 20 patients were re-assessed 10 months after total knee arthroplasty with "third condyle" PS prosthesis. All subjects were assessed with a 3D, optoelectric knee assessement device, while walking on a treadmill at a self-selected speed. For each participant, knee flexion-extension, abduction-adduction, internal-external rotation and anterior-posterior displacement, were calculated. RESULTS: The range of flexion/extension was improved significantly (39.9° ± 5.5° vs 44.8° ± 5.1°, p < 0.05) after TKA but it still remained lower than control group (6.9° ± 5.5° vs 2.2° ± 3.9°, p < 0.05). The range of motion in internal-external rotation did not change pre- and post-arthroplasty, but remained lower than the matched control group (6.7° ± 2.4° vs 9.3° ± 2.4, p < 0.05). The maximum posterior displacement during swing phase was significantly higher at post-arthroplasty group comparing with control group (-9.5 ± 2.2 vs -5.7 ± 3 mm, p < 0.05). CONCLUSION: Following "third condyle" PS-TKA, patients had better clinical, spatiotemporal and kinematic parameters. Despite improvements, the knee kinematics during gait in TKA group differed from healthy control group. TKA group had a lower extension lower range of axial rotation and an increased tibial posterior displacement.

Effects of contracture on gait kinematics: A systematic review.

BACKGROUND: Contractures of a major joint in the lower limbs may impair human walking in addition to other daily living activities. A contracture is defined as the inability of a joint to perform the full range of motion and excessive resistance during passive mobilization of the joint. Few studies have reported methods describing how to evaluate contractures. Understanding the association among all of these studies seems essential to improve patient management. Therefore, we conducted a systematic review on this topic to elucidate the influence of contractures on gait kinematics. METHODS: An electronic search in the literature will be conducted. Studies were screened by title and abstract and full texts were evaluated secondarily for definitive inclusion. The quality of the included studies was assessed independently by the two review authors with the Modified Quality Assessment Checklist. The included studies were separated into three categories: pathological contracture versus healthy controls (descriptive), simulated contracture versus healthy controls (experimental), and pre- and post-kinematics after surgical muscle lengthening (surgery). FINDINGS: From a total of 4402 references, 112 original articles were selected, and 28 studies were identified in this systematic review. No significant difference between raters was observed on the total score of the Modified Quality Assessment Checklist. INTERPRETATION: Contractures influence walking depending on the location (muscle) and the contracture level (muscle-tendon length). After giving a definition of contracture, this review identified some contracture alterations, such as plantarflexion, knee flexion and hip flexion contractures, with a kinematic description and presented possible different compensations.

Gait knee kinematics after ACL reconstruction: 3D assessment.

PURPOSE: While many studies about anterior-cruciate-ligament-deficient (ACLD) patients have demonstrated functional adaptations to protect the knee joint, an increasing number of patients undergo ACL reconstruction (ACLR) surgery in order to return to their desired level of activity. The purpose of this study was to compare 3D kinematic patterns between individuals having undergone ACLR with their healthy contralateral knee and a control group. METHODS: Three-dimensional kinematic data were obtained from 15 patients pre- and post-ACLR, 15 contralateral knees and 15 healthy controls. Data were recorded during treadmill walking at self-selected speed. Flexion/extension, external/internal tibial rotation, adduction/abduction and anterior/posterior tibial translation were compared between groups. RESULTS: ACLR knees showed a significantly higher knee-joint extension during the entire stance phase compared with ACLD knees. However, ACLR knees still showed a deficit of extension compared with healthy control knees. In the axial plane, there was no significant difference in pre- and postoperative kinematic data. Significant difference was achieved between ACLR knees and healthy control knees, specifically between 28 and 34 % and 44 and 54 % of the gait cycle. There was no significant difference in anterior-posterior translation or coronal plane between groups. CONLUSION: Following ACL reconstruction, patients have better clinical and kinematic parameters. Despite improvements, knee kinematics during gait in the ACLR group differed from the control group. These kinematic changes could lead to abnormal loading in the knee joint and initiate the process for future chondral degeneration.

The KneeKG system: a review of the literature.

PURPOSE: Accurately quantifying knee joint motion is not simple. Skin movement over the medial and lateral femoral condyles is the greatest obstacle to obtaining accurate movement data non-invasively. The KneeKG™ system was developed with the objective of providing high reliability movement analysis. The goal of this manuscript is to review the technical details, clinical evidence, and potential applications of this system for evaluation of rotational knee laxity. METHODS: A comprehensive review of the MEDLINE database was carried out to identify all clinical and biomechanical studies related to KneeKG™ system. RESULTS: The KneeKG™ system non-invasively quantifies knee abduction/adduction, axial rotation, and relative translation of the tibia and femur. The accuracy and reproducibility of the system have been assessed. The average accuracy of the acquisition is 0.4° for abduction/adduction, 2.3° for axial rotation, 2.4 mm for anteroposterior translation, and 1.1 mm for axial translation. This clinical tool enables an accurate and objective assessment of the tri-planar function of the knee joint. The measured biomechanical parameters are sensitive to changes in gait due to knee osteoarthritis and ACL deficiency. CONCLUSION: The KneeKG™ system provides reliable movement analysis. This system has the potential to improve understanding the biomechanical consequences of trauma or degenerative changes of the knee as well as more accurately quantify rotational laxity as detected by a positive pivot-shift test.