Session 4 Look at the ankle (talocrural joint) and the subtalar joint (hind foot) Anatomy of the joints Muscles and how the joints move (biomechanics) Structure of tendons and Achilles tendinitis Some common conditions including sprained ankle, involvement of the common peroneal nerve, the importance of retraining balance
Ankle and hindfoot Note medial malleolus, lateral malleolus, inferior tibiofibular joint, talocrural joint and subtalar joint form the 3 joint complex
Looking down on the talus bone Note the circumference of the medial aspect of the trochlear surface The trochlear surface is convex The circumference of the lateral aspect is longer which will influence the movement which occurs at the ankle Moving forwards the talus has a neck and convex head which articulates with the navicular (not shown) on the medial side of the foot
The calcaneus A looking down on the calcaneus, 3 areas for articulation with the talus. Note the angulation of the talus on the calcaneus B Looking at the underneath surface note the groove for the tendon of flexor halluces longus which bends the big the toe C side view of the calcaneus showing the areas for articulation with the talus
Note the domed surface of the talus which articulates with the tibia The navicular on the medial side of the foot and the cuboid on the lateral side of the foot are also shown
Anterior view of the talocrural joint and lateral view of the subtalar joint View to show the relationship of the hindfoot to the midfoot and forefoot
Lateral ligaments of the ankle The inferior tibiofibular joint has anterior and posterior ligaments plus an interosseous ligament inside the joint The lateral ligament of the ankle has 3 portions Anterior from the fibula to the talus this is the ligament most frequently injured in a sprained ankle The middle band from the fibula to the calcaneus The posterior band from the fibula to the talus Note the large gap in between the anterior and middle bands of the lateral ligament
Medial ligament of the ankle The medial ligament is fan shaped and more substantial The capsule of the ankle is thin and weak particularly anteriorly and posteriorly The stability of the joint is dependent on the ligaments
Interosseous ligament of the subtalar joint Interosseous talocalcaneal ligament lies in the tarsal canal It is a very strong ligament and is composed of collagen with little elastin
Muscles of the anterior shin Lateral to the tibia tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus longus Tibialis anterior pulls the ankle up into dorsiflexion Extensor digitorum and extensor hallucis dorsiflex the ankle and extend the toes These muscles are surrounded by fascia inelastic tissue which can cause problems if there is bleeding into the area or rapid development of the muscle. Anterior compartment syndrome see later Note also the retinacula over the front of the ankle. This is bands of fascia which prevent the tendons from bowstringing outwards when the muscle contracts
Muscles of the lateral aspect of the calf Peroneus longus and brevis are the main muscles to note Their tendons run under the lateral malleolus Peroneus longus passes under the sole of the foot to insert into the base of the first metatarsal and into the medial cuneiform (cf next week) The tendon of peroneus brevis runs along the outside of the foot to insert into the base of the 5 th metatarsal The action of these muscles which evert the foot are very important in preventing an inversion sprain of the ankle
Muscles of the posterior calf Gastrocnemius is the most superficial muscle It has a medial and lateral head arising from the medial and lateral femoral condyles The muscle bellies insert into an aponeurosis Underneath gastrocnemius is soleus This originates from the posterior fibula and tibia The muscle fibres unite to form a tendon which blends with the aponeurosis of gastrocnemius to become the tendo achilles (calcaneal tendon) which inserts onto the calcaneus
Deep posterior muscles of the calf Middle tibialis posterior arises from the interosseous membrane between the tibia and fibula, it also arises from the fibula In the lower calf it forms a tendon which runs around the medial malleolus and under the instep of the foot to insert into several bones of the foot (cf next week) The muscle can plantarflex and invert the foot Flexor digitorum longus arises from the tibia. The tendon passes alongside tibialis posterior going around the medial malleolus into the foot The muscle flexes the toes and plantarflexes the ankle Flexor hallucis longus arises from the fibula and the interosseous membrane The tendon grooves the posterior tibia and talus before passing under the instep
Synovial sheaths of the tendons The tendons are held down by bands of fascia the retinaculae They are protected by synovial sheaths shown in blue
Movements at the Talocrural joint In dorsiflexion there is some slide and roll of the talus within the mortice of the tibia and fibula The anterior and middle fibres of the ligament slacken whilst the posterior portion becomes tight In plantar flexion the anterior capsule of the joint tenses as does the anterior band of the ligament
Combined movement of the talocrural joint Several important features to note the talus is wider anteriorly than posteriorly When the foot is in full dorsiflexion the inferior tibiofibular joint widens slightly, the fibula rotates laterally and glides superiorly Therefore movement at the ankle causes movement in the inferior and superior tibiofibular joints. This is important in to consider in sprains of the ankle (cf later) Because the circumference of the lateral surface of the trochlear of the talus is longer on the lateral side plantarflexion occurs with inversion, dorsiflexion with eversion
Movement of the tibia when lunging If you stand with the right foot forwards and perform a lunge movement the tibia moves over the surface of the talus as shown This produces medial tibial rotation If rotation movements of the tibia and fibula are lost after trauma full range of movement at the ankle cannot be achieved
Combined movements of the subtalar joint The axis of the subtalar joint is offset in relation to the TC joint by 16 degrees along a line which would fall inside the big toe It is also aligned 42 degrees upward from the horizontal axis Movements at the subtalar joint, as seen below, are eversion and inversion
Visualising the subtalar joint as a boat It is easiest to imagine the subtalar joint as a boat under the ankle which can rock from side to side
Subtalar joint as a mitred hinge Classically the subtalar joint is considered as a mitred hinge (Inman and Mann 1973) Note for next week that inversion of the subtalar joint (heel) leads to supination of the foot Eversion of the subtalar joint leads to pronation of the foot Note also that the tibia rotates internally with pronation and rotates externally with supination
Combined movements in action
Any Questions?
Course of the sciatic nerve in the posterior thigh Note the close relationship to piriformis muscle in the buttock Tightness in this muscle can irritate the nerve It also runs in close proximity to the hamstring muscles Pain in this area could be related to problems with the muscle or nerve The nerve divides in the middle of the thigh into the tibial branch running down into the calf and the common peroneal nerve
Course of the common peroneal nerve The nerve divides into superficial and deep branches Note the that the deep branch winds round the neck of the fibula It is vulnerable to damage from fractures of the upper end of the fibula and trauma to the ankle, due in particular to the movement of the fibula with ankle dorsiflexion Note the proximity of the cutaneous branches to the lateral aspect of the ankle In severe inversion sprains of the ankle the nerve can be subject to traction causing pain and altered sensation Abnormal nerve function may also affect joint proprioception
Function of tendon Link between muscle and bone, muscle compliant bone stiff, graduated change in tissue characteristics between these two situations. Minimises areas of concentrated stress Muscle belly bulky, tendon allows application of force at a distance. Tendon works like a lever arm reducing the forces required to produce movement Contrasting roles tendons of fingers low stresses and strains but high precision. Achilles withstands multiples of the body weight. Also acts like a spring to store energy when stretched and releasing the energy at push off Requires degree of stiffness to provide efficient force transfer but also elastic to enable stretching and storage of energy Tendons have slightly different structures depending on specific function
Structure Cellular component-tenocytes 10% of dry weight Sensitive to mechanical loading Extracellular matrix 60-90% type I collagen Also contains 0.5-3% elastin, 2-5% proteoglycans, small amounts of other collagens Collagen interspersed with proteoglycans rich matrix Collagen molecules crosslink to build collagen fibrils, aggregated into fibres, fascicles, and then tendon The hierarchical organisation of the tendon gives tensile properties
Transition of tendon to bone Bone/tendon junction area of transition between the more flexible tendon and stiffer bone Changes from type I to type II and III fibrocartilage As closer to the bone mineralised fibrocartilage Then gradual transition to bone Called enthesis Often bursae between tendon and bone to protect the tendon
Structural differences in tendo achilles
Structure of tendo achilles In energy storing tendons, like the achilles, stretching causes sliding of the fascicles With age ability of fascicles to slide may decrease increasing the risk of injury The tendon also has a tendon sheath or paratenon protects and enhances movement Some tendons have an epitenon producing synovial fluid helping to reduce friction
Behaviour of the tendon under tension As force is applied to stretch the tendon the crimp of the fibres is pulled out The gradient of the elastic region is individual to tendon and its composition
Potential issues with the tendo achilles Midportion Achilles - tendinopathy wide-spread disorder. Prevalence of 2.01 per 1,000 patients Aetiology - multiple factors including overuse, poor vascularity, a lack of flexibility, genetic makeup, gender, endocrine, a high body mass index or metabolic factors Located about 2 6 cm proximal to Achilles tendon insertion The painful region coincides with the tendon area possessing the poorest blood supply tendon pathology continuum model describes a discrepancy between load in relation to intrinsic factors like genetics, adiposity, cholesterol, and diabetes finally leading to degeneration and insufficient regenerative capability of an individual achilles tendon
Signs and symptoms Obvious swelling of the affected area Pain on palpation Pain on toe standing Maybe palpable crepitus on plantarflexion
Treatment of achilles tendinitis Conservative modalities include load modification, eccentric exercises, orthoses, massage, electrotherapy, cryotherapy, nonsteroidal anti-inflammatory drugs extracorporeal shockwave therapy- application of acoustic shockwaves to the area. Can be high dose applied once or lower dose applied over several visits. Difficult to assess the effectiveness as different study protocols used. NICE recommends further studies Steroid injection is not recommended as it is thought that this can weaken the tendon predisposing it to rupture However, about 25 % of the patients continue to have persistent symptoms
Surgical removal of the affected paratendon Minimally invasive techniques have been found to be most successful in removing vascularised painful tissue This is followed by rehabilitation to restore range of movement, muscle strength and tensile properties of the tendon
Partial and complete tears of the tendo achilles Can occur suddenly due to increased stress on the tendon May be an audible snap or pop On examination there may be a dip or gap in the tendon Inability to toe stand in complete tear
Classic test for complete rupture of the tendon Note in a partial tear the foot may still plantarflex when the calf is squeezed If complete tear go to ED If left for more than 3 weeks cannot be repaired Depending on age and activity of the individual the injury may be treated conservatively Surgical repair is more likely to be successful in preventing recurrent tears After surgery rehabilitation is required to return to full function
Lateral ligament injuries The anterior band of the lateral ligament is most frequently damaged in an inversion sprain Typical mechanism is foot down a rabbit hole, foot on the edge of a kerb Swelling, pain and bruising over the lateral aspect of the foot In more severe injuries the calcaneofibular ligament can also be involved The tip of the lateral malleolus can be pulled off The inferior tibiofibular joint can be disrupted The tip of the base of the 5 th metatarsal can be pulled off by contraction of peroneus brevis The lateral malleolus can be fractured The cuboid can be subluxed due to the pull of peroneus longus The proximal tibiofibular joint can be subluxed The proximal fibula can also be fractured
Management of mild to moderate sprains RICE Rest, Ice, Compression, Elevation Strapping stirrup pulling the foot into dorsiflexion eversion to reduce the stress on the ligament Figure of eight strapping from the mid foot up to the calf Mobilising with a stick if required Gentle exercises after a few days to increase range of movement Progression of exercises as pain and swelling allows Retraining of balance
Severe ankle sprain Extensive bruising affecting the lateral and medial aspects of the foot Bruising over the anterior ankle may suggest damage to the ankle joint Significant swelling Inability to bear weight A feeling of instability of the ankle Suspect complete rupture of one or more ligaments Possible fractures Seek medical assistance ED Depending on the injury may require immobilisation, surgical intervention Rehabilitation to increase range of movement, muscle strength, balance If involvement of the common peroneal nerve specific techniques to restore mobility of the nerve
Sprain of the medial ligament This is a less common injury due to the strength of the medial ligament However this can lead to a fracture of the medial malleolus Severe pain, inability to bear weight, a feeling of instability, marked swelling and bruising Seek medical help for optimal management
Osteoarthritis of the ankle
Ankle joint replacement OA can follow severe ankle sprains or previous fractures If conservative management insufficient surgery may be considered Ankle arthrodesis still considered for younger patients More recently joint replacement provided in some areas Of the 30,000 cases of ankle osteoarthritis seen by hospital specialists every year in the UK, only about 1,200 of them will undergo ankle replacement surgery With ankle joint replacement there is a failure rate of up to 19% after 10 years
Ankle exercises Early mobilising exercises taking the ankle through full range dorsiflexion, plantarflexion, inversion and eversion
Increasing the range of dorsiflexion Using a belt around the foot the ankle can be pulled into more dorsiflexion Standing lunging forwards can push the ankle further into dorsiflexion
Using resistance to strengthen the dorsiflexor muscles Theraband is an elastic band which you can buy on the internet from Amazon, Tesco etc. It comes in various levels of resistance. Anchor one end to something stable Place the loop over your foot and pull up into dorsiflexion Repeat 10 times, 4 sets. 8,9 and 10 should be difficult If it becomes easy progress to the next level of resistance
Using resistance to strengthen plantar flexion The plantar flexors are generally much stronger than the dorsiflexors so you may need to start with more resistance and or progress to exercises in standing using body weight to give increased resistance
Resisted inversion and eversion Using theraband to strengthen the invertors and evertors It is important when doing this exercise that the knee and leg remain still It is easy to cheat by rolling the whole leg in and out
Stretching both calf muscles
Balance re-education Standing on tip toes with eyes open and closed Standing on one foot eyes open, eyes closed Standing on tip toes one foot eyes open, eyes closed, throwing and catching a ball Standing on an unstable surface eyes open, eyes closed, throwing and catching a ball Standing on a wobble board with two feet, with one foot, eyes open, eyes closed, throwing and catching a ball
Further rehabilitation If the persons job or hobbies involve running, hopping, jumping these activities would also be included in the rehabilitation programme Cycling, walking on the treadmill, weights in the gym are also good ways to get back to full fitness
Any questions?
Next week The foot bony architecture, muscles, how it can be both pliable to walk on rough ground but also act as a solid lever at push off The importance of the arches of the foot The foot in normal gait and posture and its influence in abnormal alignment of the lower limb Common conditions hallux valgus (bunions), heel pain, hammer toes