Electromyographic Analysis of Large Muscle Activity in Progressive Collapsing Foot Deformity.

BACKGROUND: There are various deformities described in the spectrum of Progressive Collapsing Foot Deformity (PCFD) which not only have adverse effects on the foot but also on the entire lower limb. Early lower limb muscular fatigue and pain during exertion is the most common complaint of patients with PCFD. Surface electromyography (sEMG) provides an accurate assessment of muscle activity. In this study, we aim to compare the activities of quadriceps, hamstrings, and gastrosoleus muscle groups of adult patients with PCFD with normal lower limbs and correlate the radiological parameters and functional effects of PCFD with the activities. METHODS: Thirty patients with bilateral PCFD and 30 controls underwent weight-bearing anteroposterior (AP), lateral, and hindfoot alignment radiographs of the foot. Radiographic parameters of PCFD were assessed. Surface electromyography was used to assess the quadriceps, hamstrings, and gastrosoleus activities, and this was compared between the 2 groups and correlated with radiological measurements of PCFD. Tegner activity questionnaire was used to assess the functional effects of collapsed arch. RESULTS: Electrical activities of all muscle groups were significantly higher in cases than controls. Meary's angle and hindfoot moment arm had significant correlations with hamstring activity (P = .013) and gastrosoleus activity (P = .027), respectively. Tegner scores of cases were significantly lower than those of controls (P = .041). CONCLUSIONS: The PCFD causes an increase in activity of large muscles of the affected lower limb which act on joints other than those in the foot. This finding may be due to several compensatory mechanisms that counteract the deforming forces. This may be a cause for the frequent complaint, early fatigue, and hence functional impairment. However, most radiological parameters did not correlate with muscle activities and larger study size may be required for further association. LEVELS OF EVIDENCE: Diagnostic: Level 3.

Negative pressure therapy in a scenario of distal femur fracture with internal degloving injury.

Internal degloving injuries are commonly seen in the pelvis. Similar lesions in the distal femur are rare. They cause a separation between the subcutaneous layer and deep fascia, which results in blood, lymph, necrosed fat and fluid collection in the space. They result in infection and soft tissue complications. Treatment options include conservative management with compression dressings, percutaneous aspiration, mini-incision drainage and sclerodesis. Here we describe a case of closed internal circumferential degloving injury of the distal thigh with a distal femur fracture treated by an innovative technique involving negative pressure therapy, internal fixation of the fracture and secondary skin grafting.

Navicular Tuberosity: A Surface Landmark for the Masterknot of Henry.

Background: Medial aspect of foot is unexplored due to its complex anatomy. Masterknot of Henry is an important landmark in this region, which plays a key role during tendon transfer procedures especially in those involving the flexor hallucis longus and flexor digitorum longus. We aim to determine the exact anatomical location of masterknot of Henry with respect to the bony prominences of the medial aspect of the foot and compare these measurements to the length of the foot. Methods: Twenty cadaveric below-knee specimens were dissected. Structures on the medial side of the foot were exposed. Distance of the masterknot of Henry from surrounding bony landmarks was measured. Depth of the masterknot from skin of the plantar aspect was also measured. Means of all parameters were calculated. Relation between measurements and the foot length was determined using correlation and regression analysis. P value of less than 0.05 was considered significant. Results: Distance of masterknot of Henry from navicular tuberosity was found to be fairly constant of 19.965 mm. Foot length was found to be correlating with the distance between masterknot of Henry and medial malleolus, navicular tuberosity and its depth from the skin. Conclusions: Navicular tuberosity can be considered an important surface landmark for the location of masterknot of Henry. Correlation of length of the feet with various measurements helps to find the masterknot considering the foot length to be an important variable. Good knowledge of surface anatomy leads to shorter operating time and less morbidity during procedures involving the flexor hallucis longus and flexor digitorum longus.

Rare giant schwannoma of superficial peroneal nerve on the dorsum of foot.

Schwannoma is a benign tumour of Schwann cells originating from myelin sheath of axons of the nerves. It is usually seen in the vestibular region, very rarely found in extremity regions. Schwannomas are termed 'Giant' when they measure more than five centimetres in a minimum of one dimension. Giant schwannomas in the foot and ankle region are extremely uncommon. Only eight cases of such a condition are reported. This is a case report of a giant schwannoma found arising from the superficial peroneal nerve in the dorsolateral aspect of the foot. This swelling was excised completely and the diagnosis was confirmed by histopathology.

Foot length - A reliable predictor of posterior tibial tendon thickness: A cadaveric study.

Background: Tibialis posterior tendon, deltoid ligament and spring ligament are the three most important structures on the medial aspect of the foot. They contribute to the stability of the foot and ankle and also to the maintenance of the arches of the foot. These structures get affected and dimensions get disrupted in various traumatic and degenerative conditions. Normal range of dimensions of these structures has not been studied in an Indian population. Our objective is to define the normal thicknesses of these structures using a cadaveric model. We also hypothesize that longer the foot, higher stresses on these structures and hence thicker they will be. We aim to assess this hypothesis as well. Methods: Dissection of the medial aspect of the foot was done on twenty cadaveric below knee specimens. Tibialis posterior tendon was identified and its thickness was measured. Deltoid and plantar calcaneonavicular ligaments were identified. Their lengths and thicknesses were measured. Length of the feet was also measured prior to dissection. Statistical analysis was done using the data obtained. Results: Mean tibialis posterior thickness was 7.0165 ± 0.387 mm. Mean deltoid thickness was 5.124 ± 0.28 mm. Its mean length was 21.328 ± 2.22 mm. Mean plantarcalcaneonavicular ligament thickness was 2.491 ± 1.120 mm. Thicknesses of the tibialis posterior tendon and plantarcalcaneonavicular ligament correlated significantly with the length of the foot. Conclusion: The thicknesses of the tibialis posterior tendon and plantar calcaneonavicular ligament are shown to be a function of and significantly proportional to the length of the foot. This helps the surgeon to estimate the thicknesses which the structures had prior to the pathology, in order to recreate the non-pathological anatomy after a tendon transfer or a reconstruction procedure. The normal thicknesses of tibialis posterior, deltoid and plantar calcaneonavicular ligaments are described for an Indian setting and deviations can be used to assess various pathologies of the foot and ankle affecting these structures.

Fresh Fractures: A New Indication for Use of Bone Allografts-A 10-Year Data Analysis.

Background: Tissue banking includes the process starting from procurement to the distribution and usage of allograft tissues. The use of bone bank in orthopaedics is not widely seen. Our objective is to describe the 10-year allograft donor and recipient data from a fully functioning tissue bank in India, analyse the types of grafts used, indications and demand for various grafts. This will show the need for a tissue bank in a tertiary care orthopaedic setup. Methods: Analysis of donor and recipient data for allografts of a tissue bank in an Indian tertiary care setup was done from 2012 to 2022. The number of grafts procured and used were analysed. The recipient and donor sites were also analysed. Results: In 10 years, the tissue bank provided 2776 grafts and received 1962 donations. Slices procured after total knee replacements were the most commonly used allografts (28.03%). Acute fracture with bone loss or severe comminution (23.11%) being the most common indication of bone grafting was a major result of our study. Among these, proximal tibia (27.79%) was the most frequent recipient site. Tissue bank has also served patients in neurosurgery, ophthalmology, oromaxillofacial surgery, otorhinolaryngology, urology and wound care. Conclusion: A tissue bank is a useful setup in tertiary care orthopaedic hospitals. Allografts were most widely used for acute trauma management. Allografts provide large graft quantity and reduce surgical time. Hence a tissue bank is not only an asset to the establishment but also to the surrounding hospitals, to which the grafts can be supplied.

Patterned Optogenetic Stimulation Using a DMD Projector.

Optical manipulation is a powerful way to control neural activity in vitro and in vivo with millisecond precision. Patterning of light provides the remarkable ability to simultaneously target spatially segregated neurons from a population. Commercially available projectors provide one of the simplest and most economical ways of achieving spatial light modulation at millisecond timescales. Here, we describe the protocol for constructing a projector-based spatio-temporal light patterning system integrated with a microscope on a typical electrophysiology rig. The set-up is well suited for applications requiring rapid, distinct, and combinatorial inputs, akin to brain activity. This equipment involved is fairly economical (<$5000 including all optical and mechanical components), and the set-up is easy to assemble and program.

Precise excitation-inhibition balance controls gain and timing in the hippocampus.

Excitation-inhibition (EI) balance controls excitability, dynamic range, and input gating in many brain circuits. Subsets of synaptic input can be selected or 'gated' by precise modulation of finely tuned EI balance, but assessing the granularity of EI balance requires combinatorial analysis of excitatory and inhibitory inputs. Using patterned optogenetic stimulation of mouse hippocampal CA3 neurons, we show that hundreds of unique CA3 input combinations recruit excitation and inhibition with a nearly identical ratio, demonstrating precise EI balance at the hippocampus. Crucially, the delay between excitation and inhibition decreases as excitatory input increases from a few synapses to tens of synapses. This creates a dynamic millisecond-range window for postsynaptic excitation, controlling membrane depolarization amplitude and timing via subthreshold divisive normalization. We suggest that this combination of precise EI balance and dynamic EI delays forms a general mechanism for millisecond-range input gating and subthreshold gain control in feedforward networks.