Mechanical loading is an important factor in musculoskeletal health and disease. Tendons and ligaments require physiological levels of mechanical loading to develop and maintain their tissue ...architecture, a process that is achieved at the cellular level through mechanotransduction-mediated fine tuning of the extracellular matrix by tendon and ligament stromal cells. Pathological levels of force represent a biological (mechanical) stress that elicits an immune system-mediated tissue repair pathway in tendons and ligaments. The biomechanics and mechanobiology of tendons and ligaments form the basis for understanding how such tissues sense and respond to mechanical force, and the anatomical extent of several mechanical stress-related disorders in tendons and ligaments overlaps with that of chronic inflammatory arthritis in joints. The role of mechanical stress in 'overuse' injuries, such as tendinopathy, has long been known, but mechanical stress is now also emerging as a possible trigger for some forms of chronic inflammatory arthritis, including spondyloarthritis and rheumatoid arthritis. Thus, seemingly diverse diseases of the musculoskeletal system might have similar mechanisms of immunopathogenesis owing to conserved responses to mechanical stress.
The goals of lower limb reconstruction are to restore alignment, to improve function, and to reduce pain. However, it remains unclear whether alignment of the lower limb and hindfoot are associated ...because an accurate assessment of hindfoot deformities has been limited by superposition on plain radiography. Consequently, surgeons often overlook hindfoot deformity when planning orthopaedic procedures of the lower limb. Therefore, we used weight-bearing CT to quantify hindfoot deformity related to lower limb alignment in the coronal plane.
(1) Is lower-limb alignment different in varus than in valgus hindfoot deformities for patients with and without tibiotalar joint osteoarthritis? (2) Does a hindfoot deformity correlate with lower-limb alignment in patients with and without tibiotalar joint osteoarthritis? (3) Is joint line orientation different in varus than in valgus hindfoot deformities for patients with tibiotalar joint osteoarthritis? (4) Does a hindfoot deformity correlate with joint line orientation in patients with tibiotalar joint osteoarthritis?
Between January 2015 and December 2017, one foot and ankle surgeon obtained weightbearing CT scans as second-line imaging for 184 patients with ankle and hindfoot disorders. In 69% (127 of 184 patients) of this cohort, a combined weightbearing CT and full-leg radiograph was performed when symptomatic hindfoot deformities were present. Of those, 85% (109 of 127 patients) with a median (range) age of 53 years (23 to 75) were confirmed eligible based on the inclusion and exclusion criteria of this retrospective comparative study. The Takakura classification was used to divide the cohort into patients with (n = 74) and without (n = 35) osteoarthritis of the tibiotalar joint. Lower-limb measurements, obtained from the full-leg radiographs, consisted of the mechanical tibiofemoral angle, mechanical tibia angle, and proximal tibial joint line angle. Weightbearing CT images were used to determine the hindfoot's alignment (mechanical hindfoot angle), the tibiotalar joint alignment (distal tibial joint line angle and talar tilt angle) and the subtalar joint alignment (subtalar vertical angle). These values were statistically assessed with an ANOVA and a pairwise comparison was subsequently performed with Tukey's adjustment. A linear regression analysis was performed using the Pearson correlation coefficient (r). A reliability analysis was performed using the intraclass correlation coefficient.
Lower limb alignment differed among patients with hindfoot deformity and among patients with or without tibiotalar joint osteoarthritis. In patients with tibiotalar joint osteoarthritis, we found knee valgus in presence of hindfoot varus deformity and knee varus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle 0.3 ± 2.6° versus -1.8 ± 2.1°; p < 0.001; mechanical tibia angle -1.4 ± 2.2° versus -4.3 ± 1.9°; p < 0.001). Patients without tibiotalar joint osteoarthritis demonstrated knee varus in the presence of hindfoot varus deformity compared with knee valgus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle -2.2 ± 2.2° versus 0.9 ± 2.4°; p < 0.001; mechanical tibia angle -1.8 ± 2.1° versus -4.3 ± 1.9°; p < 0.001). Patients with more valgus deformity in the hindfoot tended to have more tibiofemoral varus (r = -0.38) and tibial varus (r = -0.53), when tibiotalar joint osteoarthritis was present (p < 0.001). Conversely, patients with more valgus deformity in the hindfoot tended to have more tibiofemoral valgus (r = 0.4) and tibial valgus (r = 0.46), when tibiotalar joint osteoarthritis was absent (p < 0.001). The proximal joint line of the tibia had greater varus orientation in patients with a hindfoot valgus deformity compared with greater valgus orientation in patients with a hindfoot varus deformity (proximal tibial joint line angle 88.5 ± 2.0° versus 90.6 ± 2.2°; p < 0.05). Patients with more valgus deformity in the hindfoot tended to have more varus angulation of the proximal tibial joint line angle (r = 0.31; p < 0.05).
In patients with osteoarthritis of the tibiotalar joint, varus angulation of the knee was associated with hindfoot valgus deformity and valgus angulation of the knee was associated with hindfoot varus deformity. Patients without tibiotalar joint osteoarthritis exhibited the same deviation at the level of the knee and hindfoot. These distinct radiographic findings were most pronounced in the alignment of the tibia relative to the hindfoot deformity. This suggests a detailed examination of hindfoot alignment before knee deformity correction at the level of the proximal tibia, to avoid postoperative increase of pre-existing hindfoot deformity. Other differences detected between the radiographic parameters were less pronounced and varied within the subgroups. Future research could identify prospectively which of these parameters contain clinical relevance by progressing osteoarthritis or deformity and how they can be altered by corrective treatment.
Level III, prognostic study.
Many pro-inflammatory pathways leading to arthritis have global effects on the immune system rather than only acting locally in joints. The reason behind the regional and patchy distribution of ...arthritis represents a longstanding paradox. Here we show that biomechanical loading acts as a decisive factor in the transition from systemic autoimmunity to joint inflammation. Distribution of inflammation and erosive disease is confined to mechano-sensitive regions with a unique microanatomy. Curiously, this pathway relies on stromal cells but not adaptive immunity. Mechano-stimulation of mesenchymal cells induces CXCL1 and CCL2 for the recruitment of classical monocytes, which can differentiate into bone-resorbing osteoclasts. Genetic ablation of CCL2 or pharmacologic targeting of its receptor CCR2 abates mechanically-induced exacerbation of arthritis, indicating that stress-induced chemokine release by mesenchymal cells and chemo-attraction of monocytes determines preferential homing of arthritis to certain hot spots. Thus, mechanical strain controls the site-specific localisation of inflammation and tissue damage in arthritis.
Patients with a deformity of the hindfoot present a particular challenge when performing total knee arthroplasty (TKA). The literature contains little information about the relationship between TKA ...and hindfoot alignment. This systematic review aimed to determine from both clinical and radiological studies whether TKA would alter a preoperative hindfoot deformity and whether the outcome of TKA is affected by the presence of a postoperative hindfoot deformity.
A systematic literature search was performed in the databases PubMed, EMBASE, Cochrane Library, and Web of Science. Search terms consisted of "total knee arthroplasty/replacement" combined with "hindfoot/ankle alignment". Inclusion criteria were all English language studies analyzing the association between TKA and the alignment of the hindfoot, including the clinical or radiological outcomes. Exclusion criteria consisted of TKA performed with a concomitant extra-articular osteotomy and case reports or expert opinions. An assessment of quality was conducted using the modified Methodological Index for Non-Randomized Studies (MINORS). The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and registered in the PROSPERO database (CRD42019106980).
A total of 17 studies were found to be eligible for review. They included six prospective and ten retrospective studies, and one case-control study. The effects of TKA showed a clinical improvement in the hindfoot deformity in three studies, but did not if there was osteoarthritis (OA) of the ankle (one study) or a persistent deformity of the knee (one study). The radiological alignment of the hindfoot corrected in 11 studies, but did not in the presence of a rigid hindfoot varus deformity (in two studies). The effects of a hindfoot deformity on TKA included a clinical association with instability of the knee in one study, and a shift in the radiological weightbearing axis in two studies. The mean MINORS score was 9.4 out of 16 (7 to 12).
TKA improves both the function and alignment of the hindfoot in patients with a preoperative deformity of the hindfoot. This may not apply if there is a persistent deformity of the knee, a rigid hindfoot varus deformity, or OA of the ankle. Moreover, a persistent deformity of the hindfoot may adversely affect the stability and longevity of a TKA. These findings should be interpreted with caution due to the moderate methodological quality of the studies which were included. Therefore, further prospective studies are needed in order to determine at which stage correction of a hindfoot deformity is required to optimize the outcome of a TKA. Cite this article:
2021;103-B(1):87-97.
Abstract
Detection of syndesmotic ankle instability remains challenging in clinical practice due to the limitations of two-dimensional (2D) measurements. The transition to automated three-dimensional ...(3D) measurement techniques is on the verge of a breakthrough but normative and side-to-side comparative data are missing. Therefore, our study aim was two-fold: (1) to establish 3D anatomical reference values of the ankle syndesmosis based on automated measurements and (2) to determine to what extent the ankle syndesmosis is symmetric across all 3D measurements. Patients without syndesmotic pathology with a non-weight-bearing CT scan (NWBCT; N = 38; Age = 51.6 ± 17.43 years) and weight-bearing CT scan (WBCT; N = 43; Age = 48.9 ± 14.3 years) were retrospectively included. After training and validation of a neural network to automate the segmentation of 3D ankle models, an iterative closest point registration was performed to superimpose the left on the right ankle. Subsequently, 3D measurements were manually and automatically computed using a custom-made algorithm and side-to-side comparison of these landmarks allowed one to investigate symmetry. Intra-observer analysis showed excellent agreements for all manual measurements (ICC range 0.85–0.99) and good (i.e. < 2.7° for the angles and < 0.5 mm for the distances) accuracy was found between the automated and manual measurements. A mean Dice coefficient of 0.99 was found for the automated segmentation framework. The established mean, standard deviation and range were provided for each 3D measurement. From these data, reference values were derived to differ physiological from pathological syndesmotic alignment. Furthermore, side-to-side symmetry was revealed when comparing left to right measurements (P > 0.05). In clinical practice, our novel algorithm could surmount the current limitations of manual 2D measurements and distinguish patients with a syndesmotic ankle lesion from normal variance.
•Study observed and compared WBCT and MRI findings of Adult Flatfoot Deformity•Subtalar joint subluxation and sinus tarsi impingement are common WBCT findings•Subfibular impingement is less ...common•Spring and interosseus ligaments are the most severely degenerated soft tissues•Significant correlation between WBCT and MRI findings of Adult Flatfoot Deformity
The objective of this study was to evaluate the correlation between Weightbearing CT (WBCT) markers of pronounced peritalar subluxation (PTS) and MRI findings of soft tissue insufficiency in patients with flexible Progressive Collapsing Foot Deformity (PCFD). We hypothesized that significant correlation would be found.
Retrospective comparative study with 54 flexible PCFD patients. WBCT and MRI variables deformity severity were evaluated, including markers of pronounced PTS, as well as soft tissue degeneration. A multiple regression analysis and partition prediction models were used to evaluate the relationship between bone alignment and soft tissue injury. P-values of less than .05 were considered significant.
Degeneration of the posterior tibial tendon was significantly associated with sinus tarsi impingement (p = .04). Spring ligament degeneration correlated to subtalar joint subluxation (p = .04). Talocalcaneal interosseous ligament involvement was the only one to significantly correlate to the presence of subfibular impingement (p = .02).
Our results demonstrated that WBCT markers of pronounced deformity and PTS were significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal interosseus ligaments.
LEVEL OF EVIDENCE: Level III, Retrospective comparative study.
Category:
Ankle Arthritis; Hindfoot
Introduction/Purpose:
Dome shaped supramalleolar osteotomies are a well-established treatment option for correcting ankle deformity. However, the procedure remains ...technically demanding and is limited by a two-dimensional (2-D) radiographic planning of a three-dimensional (3-D) deformity. Therefore, we implemented a weight-bearing CT-scan (WBCT) to plan a 3-D deformity correction using patient specific guides.
Methods:
A 3-D guided dome shaped supramalleolar osteotomy was performed to correct ankle varus deformity in a cohort of 5 patients with a mean age of 53,8 years (range: 47-58). WBCT images were obtained to generate 3-D models, which enabled a deformity correction using patient specific guides. These technical steps are outlined and associated with a retrospective analysis of the clinical outcome using the EFAS score, Foot and Ankle Outcome Score (FAOS) and Visual Analog Pain scale (VAS).
Radiographic assessment was performed using the tibial anterior surface angle (TAS), tibiotalar angle (TTS), talar-tilt angle (TTA), hindfoot angle (HA), tibial lateral surface angle (TLS) and tibial rotation angle (TRA).
Results:
The mean follow-up was 40,8 months (range 8-65) and all patients showed improvements in the EFAS score, FAOS and VAS (p < 0.05). A 3-month postoperative WBCT confirmed healing of the osteotomy site and radiographic improvement of the TAS, TTS and HA (p<0.05), but the TTA and TRA did not change significantly (p>0.05).
Conclusion:
Dome shaped supramalleolar osteotomies using 3-D printed guides designed on WBCT, are a valuable option in correcting ankle varus deformity and mitigates the technical drawbacks of free-hand osteotomies.
Objective
The role of the syndesmotic ankle ligaments as extrinsic stabilizers of the distal tibiofibular joint (DTFJ) has been studied extensively in patients with high ankle sprains (HAS). However, ...research concerning the fibular incisura as intrinsic stabilizer of the DTFJ has been obscured by a two-dimensional assessment of a three-dimensional structure. Therefore, we aimed to compare the morphometry of the incisura fibularis between patients with HAS and a control group using three-dimensional radiographic techniques.
Materials and methods
Fifteen patients with a mean age of 44 years (SD = 15.2) diagnosed with an unstable HAS and twenty-five control subjects with a mean age of 47.4 years (SD = 6.5) were analyzed in this retrospective comparative study. The obtained CT images were converted to three-dimensional models, and the following radiographic parameters of the incisura fibularis were determined using three-dimensional measurements: incisura width, incisura depth, incisura height, incisura angle, incisura width-depth ratio, and incisura-tibia ratio.
Results
The mean incisura depth (M = 4.7 mm, SD = 1.1 mm), incisura height (M = 36.1 mm, SD = 5.3 mm), and incisura angle of the control group (M = 137.2°, SD = 7.9°) differed significantly from patients with a HAS (resp., M = 3.8 mm, SD = 1.1 mm; M = 31.9 mm, SD = 3.2 mm; M = 143.2°, SD = 8.3°) (
P <
0.05). The incisura width, incisura width-depth ratio, and incisura-tibia ratio demonstrated no significant difference (
P >
0.05).
Conclusion
Our three-dimensional comparative analysis has detected a shallower and shorter fibular incisura in patients with HAS. This distinct morphology could have repercussion on the intrinsic or osseous stability of the DTFJ. Future prospective radiographic assessment could determine to what extend the fibular incisura morphology contributes to syndesmotic ankle injuries caused by high ankle sprains.
Category:
Sports; Trauma
Introduction/Purpose:
Syndesmotic ankle injuries are present in one-fourth of all ankle trauma and may lead to syndesmotic instability or posttraumatic ankle osteoarthirtis ...on the long term. At present, they continue to impose a diagnostic dilemma our clinical practice. While magnetic resonance imaging lacks application of load to the ankle joint, plain weightbearing radiographs are skewed by superposition of the osseous structures. The recent advent of weightbearing cone-beam CT (WBCT) overcomes these drawbacks by imaging both ankles during bipedal stance. However, it remains debated whether syndesmotic ankle injuries should be imaged under weightbearing conditions and/or during application of external rotation. Therefore, we aimed to implement both weightbearing and external rotation in the assessment of syndesmotic ankle injuries using WBCT imaging combined with 3D measurement techniques.
Methods:
In this retrospective study, patients with an acute syndesmotic ankle injury were analyzed using a WBCT (N= 21; Age= 31.64±14.07 years old). Inclusion criteria were an MRI confirmed syndesmotic ligament injury imaged by a WBCT of the ankle during weightbearing and combined weightbearing-external rotation. Exclusion criteria consisted of fracture associated syndesmotic injuries. For the external rotation protocol, the patient was asked to internally rotate the shin while ensuring that the foot remained firmly plantigrade until pain (Visual Analogue Scale > 8/10) or a maximal range of motion was reached. 3D models were generated from the CT slices. Tibiofibular displacement and Talar Rotation were quantified by automated 3D measurements using a custom-made Matlab® script; Anterior Tibiofibular distance (ATFD), Alpha angle, posterior Tibiofibular distance (PTFD) and Talar rotation (TR) angle in comparison to the contralateral non-injured ankle.
Results:
The difference in neutral-stressed Alpha angle and ATFD showed a significant difference between patients with a syndesmotic ankle lesion and contralateral control (P = 0.046 and P = 0.039, respectively). The difference in neutral-stressed PTFD and TR angle did not show a significant difference between patients with a syndesmotic ankle lesion and healthy ankles (P = 0.492; P = 0.152, respectively).
Conclusion:
Application of combined weightbearing-external rotation reveals an increased ATFD in patients with syndesmotic ligament injuries (Figure 1). This study provides the first insights based on 3D measurements to support the potential relevance of applying external rotation during WBCT imaging. In clinical practice, this could enhance the current diagnostic accuracy of subtle syndesmotic instability in a non-invasive manner. However, future studies are required to determine cut-off values that may indicate the amount of displacement that might lead to chronic instability and require a certain type of treatment strategy.
Category:
Hindfoot; Sports
Introduction/Purpose:
The use of a dorsal closing wedge calcaneal osteotomy (DCWCO) in the treatment of insertional Achilles tendinopathy (IAT) has recently gained ...popularity. The anatomical changes imposed by the osteotomy are believed to improve both the biological and mechanical processes involved in IAT. However, the impact of shortening the Achilles leverage arm after DCWCO and the full impact of DCWCO on foot anatomy and function is not well understood. This study aimed to examine the effects of DCWCO on the 3D alignment and biomechanics of the foot and ankle in IAT patients through simulated models of DCWCO. The hypothesis was that DCWCO would significantly impact foot alignment and decrease gastrocsoleus lever arm.
Methods:
Six weightbearing ankle CTs of patients with IAT were identified from the clinical database. Bone segmentation was performed and DCWCOs were conducted in standardized planes with six variations, resulting in a total of 36 foot models. Two plantar osteotomy starting points were defined as 1-cm anterior (posterior osteotomy) and 2-cm anterior (anterior osteotomy) to the most plantar point of calcaneus. The osteotomies were extended to dorsal surface at 1-cm anterior to posterosuperior calcaneus with 6, 10, or 14-mm wedges anteriorly. After the osteotomies, the posterior part of the calcaneus was rotated around the plantar starting point until proper bone contact was achieved. Achilles reconstruction was also performed using pre-defined Achilles insertion points. All models were then transferred to a MATLAB-based algorithm for automated measurements. These measurements included talocalcaneal, calcaneal pitch, Böhler, and Achilles tendon sagittal angles, Achilles moment arm, Achilles- posterosuperior calcaneus distance, and difference in soleus-Achilles length.
Results:
Anteriorly placed osteotomy caused more significant decrease in the Böhler angle (p < 0.001). Evaluation of the posteriorly placed osteotomy separately showed no significant decrease in the Böhler angle for patients with more than 30- degrees of preoperative Böhler angle (p=0.26). However, patients with a preoperative Böhler angle less than 30-degrees showed a significant decrease, approaching values close to 5-degrees (p=0.004). Gastrocsoleus moment arm decrease was found to be 2-3% by using force/moment equation. The change in the distance between Achilles tendon and the posterosuperior calcaneus was similar between anterior and posterior osteotomies, with less than 3-mm in a 6-mm wedge and more than 5-mm in a 10-mm wedge osteotomy. The calculations showed that ankle dorsiflexion can increase by one degree for each mm of resection.
Conclusion:
An anteriorly placed starting point for a DCWCO can negatively affect foot alignment and offer limited benefits for Achilles decompression. If the preoperative Böhler angle is less than 30, a DCWCO can significantly decrease the Böhler angle, potentially putting the subtalar joint at risk for arthritis by increasing the load as reported by some finite element studies. The maximum decrease in gastrocsoleus power is less than 3%, which may be clinically insignificant. A posterior starting point with 10- mm wedge can be adequate to move Haglund around 5-mm anteriorly and can move Achilles insertion 10-mm superiorly to decrease tension.
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