Assessing the coronal plane deformity in Charcot Marie Tooth Cavovarus feet using automated 3D measurements.

BACKGROUND: This study assesses the coronal-plane deformities in cavovarus feet secondary to Charcot-Marie-Tooth disease (CMT) using Weightbearing-CT (WBCT) and semi-automated 3D-segmentation software. METHODS: WBCTs from 30 CMT-cavovarus feet were matched to 30 controls and analysed using semi-automatic 3D-segmentation (Bonelogic, DISIOR). The software used automated cross-section sampling with subsequent straight-line representation of weighted centre points to calculate 3D axes of bones in the hindfoot, midfoot and forefoot. Coronal relationships of these axes were analysed. Supination/pronation of the bones in relation to the ground and within each joint were measured and reported. RESULTS: The most significant deformity in CMT-cavovarus feet occurred at the talonavicular joint (TNJ) with 23 degrees more supination than normal feet (6.4 ± 14.5 versus 29.4 ± 7.0 degrees, p < 0.001). This was countered by relative pronation at the naviculo-cuneiform joints (NCJ) of 7.0 degrees (-36.0 ± 6.6 versus -43.0 ± 5.3 degrees, p < 0.001). Combined hindfoot varus and TNJ supination resulted in an additive supination effect not compensated by NCJ pronation. The cuneiforms in CMT-cavovarus feet were therefore supinated by 19.8 degrees to the ground relative to normal feet (36.0 ± 12.1 versus 16.2 ± 6.8 degrees, p < 0.001). The forefoot-arch and 1st metatarsal-ground angles demonstrated similar supination to the cuneiforms suggesting no further significant rotation occurred distally. CONCLUSION: Our results demonstrate coronal plane deformity occurs at multiple levels in CMT-cavovarus feet. Majority of the supination arises at the TNJ, and this is partially countered by pronation distally, mainly at the NCJ. An understanding of the location of coronal deformities may help when planning surgical correction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Semi-automated 3-dimensional analysis of the normal foot and ankle using weight bearing CT - A report of normal values and bony relationships.

BACKGROUND: Foot and ankle deformities have translational and rotational components in multiple planes, at multiple levels. Semi-automatic segmentation is a relatively new technology, which when used with weight-bearing CT (WBCT), can build an accurate model of the foot and calculate the orientation and relationships of bones under physiological load. However, few papers report reference values using these techniques. We report normative values for key bony relationships based on semi-automated analysis of WBCT. METHODS: This was a single-centre, retrospective analysis of 100 feet without deformity from 55 adult patients undergoing WBCT as part of routine clinical activity (mean age 40.5 ± 17.3 years). Imaging was analysed using Bonelogic 2.1 (DISIOR, Finland). Semi-automatic segmentation was used to compute the various bony axes in 3-dimensional space. Selected coronal, axial and sagittal plane relationships were then calculated for bones of the hindfoot, midfoot and forefoot. RESULTS: Data is presented on axial and sagittal plane relationships between the metatarsals in the forefoot, and the metatarsals and cuneiforms in the midfoot. In the hindfoot, the calcaneal pitch, talar-first-metatarsal angles, talonavicular coverage angles and Saltzman angles are reported. Coronal plane axes and their relationships are reported at multiple levels from hindfoot to forefoot. Results are presented as mean values with standard deviations and 95% confidence intervals. CONCLUSIONS: We present an observational analysis of the normal values from non-deformed feet. We highlight the major relationships in the axial, sagittal and coronal planes as obtained by semi-automated analysis of WBCT. This data may serve as a reference for future research. LEVEL OF EVIDENCE: Basic science study.

2D Manual vs 3D Automated Assessment of Alignment in Normal and Charcot-Marie-Tooth Cavovarus Feet Using Weightbearing CT.

BACKGROUND: The complex deformities in cavovarus feet may be difficult to assess and understand. Weightbearing computed tomography (WBCT) is increasingly used in evaluating complex deformities. However, the bone axes may be difficult to calculate in the setting of severe deformity. Computer-assisted 3D axis calculation is a novel approach that may allow for more accurate assessment of foot alignment or deformity. This study aimed to assess differences in measurements done manually on 2D slices of WBCT vs 3D computer models in normal and cavus feet. METHODS: We retrospectively analyzed WBCT scans from 16 normal and 16 cavus feet in patients with Charcot-Marie-Tooth disease. Six measurements were assessed: talar-first metatarsal angle (axial plane), forefoot arch angle (coronal plane), and Meary angle, calcaneal pitch, and cuneiform and navicular to floor distances (sagittal plane). 2D measurements were performed manually and 3D measurements were performed using specialized software (Bonelogic, DISIOR). Bland-Altman plots and linear regression were used to analyze differences. RESULTS: There were no significant biases in measured variables in normal feet. In the cavovarus group, automated assessment calculated increased sagittal plane deformity (fixed bias 7.31 degrees for Meary angle, 2.39 degrees for calcaneal pitch) and less axial plane deformity (fixed bias 10.61 degrees for axial talar-first metatarsal angle). The latter also demonstrated proportional bias indicating greater discrepancy with increasing adduction. CONCLUSION: Measurements were comparable in normal feet suggesting automated techniques can reliably assess the alignment of bony axes. However, automated calculations show greater sagittal and less axial deformity in cavovarus feet than measured by manual techniques. This discrepancy may relate to rotational deformity seen in cavovarus feet, which may not be easily assessed manually. 3D automated measurements may therefore play a role in better assessing and classifying the cavovarus foot, which may ultimately inform treatment algorithms. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Does Patellar Resurfacing Matter? Midterm Follow-Up of MRK Total Knee Replacement.

BACKGROUND: Many designs of TKR have been developed to optimize the kinematics and improve satisfaction, including the 'medial rotating' philosophy. The purpose of this study is to report the mid-term clinical outcome of MRK knees and evaluate whether resurfacing the patella makes any difference in outcome. METHODS: A retrospective analysis was done of 104 MRK total knee replacement done between 2008 and 2017. Patients were called for a review for evaluation of OKS, Baldini and Feller scores. Demographics of the patients, clinical outcome, complications were assessed. RESULTS: 62 had patellar resurfacing. Mean follow-up was 74.45 months in non- resurfaced and 54.93 months in resurfaced group. Mean flexion range in both groups at final follow-up was 101.45. Median OKS at follow-up was 36 (12-47) in non-resurfaced and 37 (9-48) in resurfaced group. Patella scores were better in resurfaced group-Baldini score median (range) was 90 (25-100) in non-resurfaced v/s 100 (30-100) in resurfaced, Feller score median (range) was 25 (12-30) in non-resurfaced v/s 28 (10-30) (p 0.042) in resurfaced. The patellofemoral component of the OKS (Q5 + Q7 + Q12) median showed an improvement from 3 (1-11) to 6.5 (3-11) in non-resurfaced and from 3 (0-12) to 8 (2-12) (p 0.039) in resurfaced group. There were five complications overall (4.8%). CONCLUSION: These results show a satisfactory outcome at mid-term follow-up. We found a statistically significant difference in Feller score and in the patellofemoral component of OKS between the groups of MRK knee suggesting specific benefits of patellar resurfacing with this implant.

Low trauma posterior native hip dislocation with acute longitudinal transverse myelitis due to SARS-CoV-2 - A case-report.

BACKGROUND: Native hip dislocations are most commonly seen after high energy trauma. While there are documented cases of hip dislocation with associated stroke, we present a case of posterior hip dislocation in the context of acute longitudinal transverse myelitis due to a rare presentation of SARS-CoV-2. CASE REPORT: A 60-year-old male presented with bilateral lower limb weakness with a shortened internally rotated left leg. Plain radiographs revealed a posteriorly dislocated native left hip and MRI of the spine showed acute longitudinal transverse myelitis of the cervical and thoracic regions. His nasopharyngeal swab was positive for SARS-CoV-2. His hip was reduced, and he was treated with intravenous steroids. His neurological symptoms improved with follow-up MRI showing resolution of the transverse myelitis. CONCLUSION: This case illustrates a classic orthopaedic emergency in the context of a rare presentation of SARS-CoV-2, and the vigilance that orthopaedic doctors must have when examining patients with lower limb neurological deficit.

Introducing a Virtual Fracture Clinic Increases Efficiency and Reduces Costs in Torus Fracture Management.

Torus fractures of the distal radius are both a common pediatric forearm fracture and a common source of referral to orthopedic departments. Management of these injuries has moved away from traditional casting methods to using splints and softcasts. AIM: With the recent introduction of a virtual fracture clinic (VFC), we sought to improve our compliance with guidelines while ensuring all patients undergo review in the clinic. METHODS: We audited the management of patients before and after the introduction of the VFC with new management protocols for torus fracture patients. RESULTS: There was a 51% decrease in patients managed using plaster of Paris with 5% treated with a softcast and 59% using a splint. OUTCOME: Using the VFC can improve the management of patients with torus fractures and provide a cost-saving and a more positive experience for patients.