Biomechanical effects of rocker shoes on plantar aponeurosis strain in patients with plantar fasciitis and healthy controls

Multibody dynamics-based musculoskeletal modeling for gait analysis: a systematic review

Beyond qualitative assessment, gait analysis involves the quantitative evaluation of various parameters such as joint kinematics, spatiotemporal metrics, external forces, and muscle activation patterns and forces. Utilizing multibody dynamics-based musculoskeletal (MSK) modeling provides a time and cost-effective non-invasive tool for the prediction of internal joint and muscle forces. Recent advancements in the development of biofidelic MSK models have facilitated their integration into clinical decision-making processes, including quantitative diagnostics, functional assessment of prosthesis and implants, and devising data-driven gait rehabilitation protocols. Through an extensive search and meta-analysis of over 116 studies, this PRISMA-based systematic review provides a comprehensive overview of different existing multibody MSK modeling platforms, including generic templates, methods for personalization to individual subjects, and the solutions used to address statically indeterminate problems. Additionally, it summarizes post-processing techniques and the practical applications of MSK modeling tools. In the field of biomechanics, MSK modeling provides an indispensable tool for simulating and understanding human movement dynamics. However, limitations which remain elusive include the absence of MSK modeling templates based on female anatomy underscores the need for further advancements in this area.

The Heel Complex: Anatomy, Imaging, Pathologic Conditions, and Treatment

The differential diagnosis for heel pain is broad but primarily involves abnormalities of the Achilles tendon, calcaneus, and plantar fascia. Achilles tendon disorders include tendinosis, tendinitis, and partial or complete tears. Tendinosis refers to tendon degeneration, while tendinitis is inflammation after acute overload. Untreated tendinosis can progress to partial or complete tears. Tendon disorders can be accompanied by paratenonitis or inflammation of the loose sheath enclosing the tendon. Initial management involves rehabilitation and image-guided procedures. Operative management is reserved for tendon tears and includes direct repair, tendon transfer, and graft reconstruction. The calcaneus is the most commonly fractured tarsal bone. The majority of fractures are intra-articular; extra-articular fractures, stress or insufficiency fractures, medial process avulsion, and neuropathic avulsion can also occur. Posterosuperior calcaneal exostosis or Haglund deformity, retrocalcaneal bursitis, and insertional Achilles tendinosis form the characteristic triad of Haglund syndrome. It is initially managed with orthotics and physiotherapy. Operative management aims to correct osseous or soft-tissue derangements. The plantar fascia is a strong fibrous tissue that invests the sole of the foot and contributes to midfoot stability. Inflammation or plantar fasciitis is the most common cause of heel pain and can be related to overuse or mechanical causes. Acute rupture is less common but can occur in preexisting plantar fasciitis. Conservative treatment includes footwear modification, calf stretches, and percutaneous procedures. The main operative treatment is plantar fasciotomy. Plantar fibromatosis is a benign fibroblastic proliferation within the fascia that can be locally aggressive and is prone to recurrence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

The rocker-soled shoes change the kinematics and muscle contractions of the lower extremity during various functional movement

While rocker-shaped soles have become popular for running shoes, whether or not this type of shoe benefits other functional movements has rarely been discussed. The purpose of this study was to investigate the effect of rocker-soled shoes on lower extremity biomechanics during different exercises. Seventeen healthy university students were recruited. A motion capture analysis system and surface electromyography were used to measure kinematics and muscle activation while walking (10 m), running (10 m), cutting, jumping, and ascending and descending stairs. The results showed that when wearing rocker-soled shoes, greater peak external ankle rotation was present during most exercises. Smaller peak joint angles were observed in hip extension and external rotation when walking, and in ankle dorsiflexion when ascending stairs and jumping. The vastus medialis and vastus lateralis contracted more in most exercises when rocker-soled shoes were worn. However, the biceps femoris and medial gastrocnemius showed less muscle contraction. Wearing rocker-soled shoes during testing movements change the kinematics and muscle contractions of the lower extremity. These findings may provide information for choosing shoes for different exercises or training purposes.

Immunopathogenesis, early Detection, current therapies and prevention of plantar Fasciitis: A concise review

Plantar fasciitis or the inflammation of the fascial lining on the plantar aspect of the foot continues to be the leading cause of heel pain for many Americans. Common causes can range from anatomical deformities such as pes planus or flat foot, biomechanical etiology such as excessive pronation of the subtalar joint, or chronic diseases such as obesity and diabetes mellitus. The pathophysiology of plantar fasciitis can be either inflammatory due to vasodilation and immune system activation or non-inflammatory involving fibroblastic hypertrophy. Worsening pain of the inferior and medial heel after periods of prolonged rest and late in the day after hours of ambulation and weight-bearing activities is the most common symptom of plantar fasciitis. Common treatments for plantar fasciitis include plantar fascia stretching, physical therapy, orthotics, corticosteroid injections, and even surgery. Despite these treatment strategies, fasciitis remains a clinical problem and better treatment modalities are warranted. Late diagnosis is a common issue for prolonged and equivocal treatment and early diagnostic measures might be beneficial. In this concise review, we discussed the etiology, immunopathogenesis, current treatments of plantar fasciitis and potentially preventative measures prior to the onset of chronic treatment resistant condition.

Effects of Longitudinal Bending Stiffness of forefoot rocker profile shoes on ankle kinematics and kinetics

INTRODUCTION

Rocker profile shoes with a proximally placed apex are currently one of the most prescribed shoe modifications for treatment and prevention of lower leg deficits. Three geometrical rocker design parameters apex position (AP), apex angle (AA) and rocker radius (RR) influence both plantar pressure redistribution and kinetic and kinematic alterations of the lower leg. In addition, longitudinal bending stiffness (LBS) of the outsole influences these parameters as well. This study aims to investigate the effects of the LBS in combination with different forefoot radii of rocker shoes on kinematics and kinetics of the lower limb.

METHODS

10 participants walked in standard shoes and six experimental shoe conditions with high and low LBS and three different forefoot rocker radii with the same (proximal) AP and AA. Lower extremity kinematics and kinetics were collected while walking on an instrumented treadmill at preferred walking speed and analysed with a repeated measures ANOVA and Statistical Parametric Mapping (SPM) (α = .05; post hoc α = .05/6).

RESULTS

SPM analyses revealed no significant differences for LBS and interaction LBS*RR for most research variables in terminal stance (ankle angle, ankle moment, ankle power, foot-to-horizontal angle, shank-to-vertical angle, external ankle moment, ground reaction force angle). A significant LBS effect was found for anterior-posterior position of the centre of pressure during pre-swing and peak ankle dorsiflexion angle. No relevant significant differences were found in spatio-temporal parameters and total work at the ankle between low and high LBS.

CONCLUSION

This study showed that longitudinal bending stiffness does not affect the biomechanical working mechanism of rocker profile shoes as long as toe plantarflexion is restricted. Providing that the forefoot rocker radius supports at least a normal foot-to-horizontal angle at toe-off, there is no reason to increase sole stiffness to change ankle kinematics and kinetics.

Effects of rocker radii with two longitudinal bending stiffnesses on plantar pressure distribution in the forefoot

INTRODUCTION

Outsole parameters of the shoe can be adapted to offload regions of pain or region of high pressures. Previous studies already showed reduced plantar pressures in the forefoot due to a proximally placed apex position and higher longitudinal bending stiffness (LBS). The aim of this study was to determine the effect of changes in rocker radii and high LBS on the plantar pressure profile during gait.

METHOD

10 participants walked in seven shoe conditions of which one control shoe and six rocker shoes with small, medium and large rocker radii and low and high longitudinal bending stiffness. Pedar in-shoe plantar pressure measuring system was used to quantify plantar pressures while walking on a treadmill at self-selected walking speed. Peak plantar pressure, maximum mean pressure and force-time integral were analyzed with Generalized Estimated Equation (GEE) and Tukey post hoc correction (α = .05).

RESULTS

Significantly lower plantar pressures were found in the first toe, toes 2-5, distal and proximal forefoot in all rocker shoe conditions as compared to the control shoe. Plantar pressures in the first toe and toes 2-5 were significantly lower in the small radius compared to medium and large radii. For the distal forefoot both small and medium radii significantly reduced plantar pressure compared to large radii. Low LBS reduced plantar pressure at the first toe significantly compared to high LBS independent of the rocker radius. Plantar pressures in the distal forefoot and toes 2-5 were lower in high LBS compared to low LBS.

CONCLUSION

Manipulation of the rocker radius and LBS can effectively reduce peak plantar pressures in the forefoot region during gait. In line with previous studies, we showed that depending on the exact target location for offloading, different combinations of rocker radius and LBS need to be adopted to maximize treatment effects.

Effect of different forefoot rocker radii on lower-limb joint biomechanics in healthy individuals

INTRODUCTION

Previous studies showed that rocker shoes with a stiff forefoot rocker profile significantly reduce peak plantar flexion moment at the ankle (PFM) and peak ankle dorsiflexion (DF). Both parameters are related to Achilles tendon and Plantar Fascia unloading. The shape of an outsole with a forefoot rocker is described with multiple rocker design parameters. The aim of this research is, to determine the relation between different forefoot rocker radii on peak DF and peak PFM at a self-selected walking speed.

METHODS

10 participants walked in standard shoes and three experimental pairs of shoes with different forefoot rocker radii. Lower extremity kinematics and kinetics were collected while walking on an instrumented treadmill at preferred walking speed and analysed with Statistical Parametric Mapping (SPM) (α = .05; post-hoc α = .05/6).

RESULTS

Peak value analyses showed significant decreases in peak DF, peak PFM, and peak ankle power generation for the rocker conditions. No relevant significant differences were found in spatio-temporal parameters and total work at the ankle joint. SPM showed a significant decrease (% gait cycle) in DF (40-69 %), PFM (7-15 %; 41-68 %; 69-81 %), ankle power (10-15 %; 32-51 %; 55-64 %; 64-67 %; 72-80 %) and foot-to-horizontal angle (FHA) (0-4 %; 40-62 %; 92-100 %) and an increased shank-to-vertical angle (SVA) (44-84 %) for the rocker conditions.

CONCLUSION

The results of this study suggest that rocker shoes with a proximally placed apex significantly reduce DF and PFM during the third rocker compared with control shoes. This effect is mainly explained by a change in the FHA. Smaller radii cause the largest reductions in DF and PFM, so therefore, a uniform standardisation of the forefoot rocker radius is essential.