Ankle and Foot Pain



Ankle and Foot Pain


David S. Levine





KEY POINTS



  • A sound understanding of foot and ankle anatomy is essential for establishing the cause of associated pathologies.


  • Understanding the “essential” nature of the mobile hindfoot and forefoot joints and the “nonessential”, rigid nature of the midfoot joints is important.


  • With the exception of acute fractures, weight-bearing plain radiographs provide the most important information for the diagnosis and treatment of foot and ankle pathologies.



  • Understanding the contribution of the “tight” or shortened Achilles tendon in the pathogenesis of posterior tibial tendon insufficiency and plantar fasciitis is important.


  • Understanding the contribution of a “hypermobile” first ray in the presence of hallux valgus deformity, as well as the generation of second metatarsal overload conditions (metatarsalgia, hammertoes, and stress fracture of the second metatarsal, etc.), is important.


ANATOMY



  • The joints of the foot and ankle can be divided into two groups: essential joints, which have appreciable motion and are “required” for normal functioning of the foot, and nonessential joints, which have little appreciable motion and are largely responsible for providing stability.



    • Essential joints



      • The ankle (tibiotalar) joint maintains an axis through the malleoli such that dorsiflexion and external foot rotation are coupled. Similarly, plantar flexion and internal foot rotation are coupled motions. Surrounding ligamentous structures limit inversion or eversion through the ankle joint.


      • The subtalar (talocalcaneal) joint is responsible for hindfoot inversion and eversion. Motion occurs around an axis inclined 15 degrees lateral to the longitudinal axis of the foot. Along with the ankle joint, the subtalar joint forms a “universal joint”, thereby enabling the hindfoot to accommodate to uneven surfaces.


      • The talonavicular and calcaneocuboid (transverse tarsal) joints function to link the mobile hindfoot to the immobile midfoot.


      • The metatarsophalangeal (MTP) joints of the forefoot have significant dorsiflexion and plantar flexion capability, which enables the center of gravity of the body to be propelled forward efficiently at the end of the gait cycle.


    • Nonessential joints such as the navicular-cuneiform, intercuneiform, and tarsometatarsal joints (collectively known as the “midfoot”) have little motion because of stout ligamentous reinforcement. These joints serve to provide a rigid lever-arm during weight transfer from the hindfoot to the forefoot. Movement in this part of the foot is considered to be pathologic.


  • LIGAMENTS



    • The deltoid ligament is the prime stabilizer of the medial (inner) side of the ankle joint. It runs from the medial malleolus to the talus, calcaneus, and navicular. Its deep portion resists lateral translation of the talus within the ankle joint. The superficial portion blends with other capsular and ligamentous structures over the medial hindfoot.


    • The lateral collateral ligaments consist of the anterior and posterior talofibular ligaments and the calcaneofibular ligament. As a group, these ligaments are the prime stabilizers of the lateral (outer) side of the ankle joint. The anterior talofibular ligament is the most frequently injured ligament, especially during plantar flexion of the foot. With increasing energy of motion or when the foot is in a neutral position or in slight dorsiflexion, the calcaneofibular ligament may also be injured.


    • The plantar talocalcaneonavicular (spring) ligament has been increasingly noted to be important in supporting the head of the talus and in preventing loss of the medial longitudinal arch height.


    • The plantar intertarsal (interosseous) ligaments (the long and short plantar ligaments, as well as the many intertarsal ligaments, are often collectively referred to as the plantar intertarsal ligaments) stabilize the bones of the midfoot, thereby maintaining their static contribution to the medial longitudinal arch.


  • MUSCLES



    • Movement: dorsiflexion of the foot and ankle;


    • Muscles effecting that movement: tibialis anterior, extensor digitorum longus, extensor hallucis longus, and peroneus tertius.


    • Movement: plantar flexion of the foot and ankle;


    • Muscles effecting that movement: gastrocnemius and soleus.



    • Movement: hindfoot inversion;


    • Muscles effecting that movement: posterior tibialis and gastrocnemius.


    • Movement: hindfoot eversion;


    • Muscles effecting that movement: peroneus brevis and peroneus longus. The intrinsic muscles of the foot contribute to the bulk and padding of the sole, help maintain the architecture of the transverse and longitudinal arches, and influence the alignment of the toes. The toes are flexed and extended by their long and short flexors and extensors, respectively.


  • FASCIA. The plantar fascia originates on the posteromedial tubercle of the calcaneus and inserts into the bases of the proximal phalanges via the plantar plate and flexor tendon sheaths. It maintains a static support of the longitudinal arch via a “windlass” mechanism (the windlass mechanism refers to the ability of the plantar fascia to elevate the longitudinal arch of the foot when the great toe is dorsiflexed). This mechanism is observed at the push-off phase of the gait pattern and supports the arch during this period of high force transmission.


  • The blood supply of the ankle and foot comes principally from the dorsalis pedis artery (an extension of the anterior tibialis artery), which is palpable between the first and second metatarsal bases on the dorsum of the foot, and the posterior tibialis artery, which is palpable about one finger’s breadth posterior and inferior to the medial malleolus. Communicating branches from the peroneal artery provide an inconsistent anastomosis with the above-named arteries.


  • Innervation of the foot and ankle is from the superficial and deep peroneal nerves, which supply the dorsum of the foot. The medial and lateral plantar nerves provide sensation to the plantar surface of the foot and innervate the intrinsic muscles. The sural nerve provides sensation to the outer border of the heel and the dorsolateral border of the foot. The saphenous nerve, a terminal branch of the femoral nerve, provides sensation to the medial border of the ankle and foot.


HISTORY


I. PAIN



  • Exact localization of pain and radiation to other areas.


  • Aggravating and alleviating factors.


  • Associated findings.


  • Acute or insidious onset.


  • Traumatic or atraumatic.


  • Intensity.


  • Quality (radiating pain with an “electric” quality may be consistent with neuroma).


II. FOOTWEAR



  • Recent alterations in usual footwear (i.e., heel height) should be taken into account.


  • Attitude toward footwear influences expectations.


  • Barefoot activities can be associated with increased or decreased symptoms.


III. PAST MEDICAL HISTORY

Numerous conditions, including gout, rheumatoid arthritis (RA), neoplasm, peripheral vascular disease, diabetes mellitus, congenital deformity, and neurologic conditions, can contribute to foot or ankle dysfunction. Similarly, the altered gait pattern related to foot and ankle dysfunction can contribute to other musculoskeletal complaints, such as lower-back pain, hip pain, and medial knee pain. Similarly, musculoskeletal dysfunction and pain arising from those joints can alter the gait pattern and can have an impact upon the foot. Often, the ultimate disability is the integral of all of these factors. A deformity of the knee may be associated with a “compensatory” deformity of the foot.


IV. PAST SURGICAL HISTORY

Any prior history of surgical procedures on the foot and ankle should be thoroughly discussed.


PHYSICAL EXAMINATION



  • Gait and alignment should be evaluated with the patient in shoes and barefoot.



    • At heel-strike, the hindfoot should assume a valgus attitude, allowing shock absorption through the flexible hindfoot. Weight is transferred forward during
      foot-flat. At heel-rise, the hindfoot is inverted (by the tibialis posterior muscle). The transverse tarsal joint becomes rigid when the hindfoot is inverted, enabling the body weight to be transferred through the rigid midfoot to the MTP joints preparing for toe-off. The swing phase then completes the gait cycle.


    • An antalgic gait involves a shortened stance phase, which signifies a painful limb.


    • A steppage gait involves hip and knee flexion to clear the foot during swing phase in the setting of a “drop foot” (e.g., after a peroneal nerve palsy).


    • The patient’s standing position should be observed from behind. Physiologic hind foot valgus (i.e., away from the midline) should be readily apparent. Excessive valgus (as in a flatfoot) or hindfoot varus (as in clubfoot sequelae or the cavovarus foot) should be noted.


    • Heel-rise should be associated with hindfoot inversion (a tibialis posterior function).


    • Total limb alignment should be evaluated from the hips to the toes.


    • Rotational deformities (i.e., intoeing) due to internal tibial torsion or excessive femoral anteversion are best evaluated with the patient in the prone position.


  • Range of motion should be compared with that of the contralateral extremity. Both active and passive range of motion should be evaluated.

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Jul 29, 2016 | Posted by in RHEUMATOLOGY | Comments Off on Ankle and Foot Pain

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