شارکو نیورو آرتھروپیتھی

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Anatomy & Pathophysiology¶

Bony Anatomy¶

• The ankle mortise is formed by the tibial plafond, medial malleolus, and lateral malleolus [3].
• The ankle mortise articulates with the dome of the talar body [3].
• The talar dome is wider anteriorly and narrower posteriorly [3].
• The ankle mortise widens 1 to 1.5 mm during motion from plantar flexion to dorsiflexion [3].
• Medial and superior clear spaces appear wider with the foot in plantar flexion [3].
• The distal fibula has a convex medial surface that articulates with the concave incisura fibularis of the distal lateral tibia [3].
• The fibula rotates approximately 2 degrees within the incisura during ankle motion and ambulation [3].
• Ankle dorsiflexion results in external rotation and proximal translation of the fibula [3].
• The primary functions of the foot and ankle are to provide weight-bearing support and forward ambulation [3].

Ligamentous Anatomy¶

• The lateral ankle ligaments function as restraints to varus and inversion forces at the ankle [3].
• The anterior talofibular ligament (ATFL) originates from the anteroinferior aspect of the lateral malleolus, 1 cm proximal to its tip, and extends to the lateral aspect of the talar neck [3].
• The calcaneofibular ligament (CFL) extends from the tip of the lateral malleolus to the lateral aspect of the calcaneus [3].
• The posterior talofibular ligament (PTFL) extends from the posterior lateral malleolus to the posterolateral talus [3].
• The ATFL is the weakest ankle ligament [3].
• The PTFL is the strongest ankle ligament [3].
• The distal tibiofibular joint (ankle syndesmosis) and fibula provide stability against lateral talar translation [3].
• The deltoid ligament complex is the primary ankle stabilizer during stance [3].
• The deep deltoid ligament extends from the apex of the medial malleolus to the medial talar body [3].
• The deep deltoid ligament functions primarily to resist lateral talar translation and external rotation [3].
• The posterior deep deltoid is the most important component of the deep deltoid ligament [3].
• The superficial deltoid ligament extends from the distal medial malleolus to the navicular bone, sustentaculum tali of the calcaneus, medial talus, and spring ligament [3].
• The superficial deltoid ligament functions primarily to resist valgus and eversion ankle forces [3].
• The deltoid ligament consists of superficial and deep layers, with at most six bands, of which only three are constant: the tibionavicular ligament, tibiospring ligament, and deep posterior tibiotalar ligament [8].
• The superficial layer of the deltoid ligament originates from the anterior malleolus and inserts into the navicular, neck of the talus, sustentaculum tali, and posteromedial talar tubercle [8].
• The tibiocalcaneal portion of the superficial deltoid ligament is the strongest component and resists eversion of the calcaneus [8].
• The deep portion of the deltoid ligament is organized into two short, thick, discrete bands: the anterior and posterior deep tibiotalar ligaments [8].
• The anterior and posterior deep tibiotalar ligaments are intra-articular but extrasynovial [8].
• The deep posterior band comprises the largest band of the deltoid complex [8].
• The anterior deep tibiotalar ligament arises from the anterior malleolus and attaches to the medial aspect of the talus [8].
• The posterior deep tibiotalar ligament originates from the posterior malleolus and inserts on the medial body of the talus [8].
• The deltoid ligament has a rich vascular supply from three extraosseous sources: the medial tarsal artery, posterior tibial artery, and tibialis anterior artery [8].
• The deltoid ligament also has an intraosseous vascular supply from either the talus or the medial malleolus [8].
• The deep deltoid ligament has the highest load to failure at 713.8 N ± 69.3 compared with the lateral collateral ligaments [8].
• The dominant mode of failure for the deep deltoid ligament is an intrasubstance rupture near its talar insertion [8].
• The dominant mode of failure for the superficial deltoid ligament is at its insertion on the anterior malleolus [8].

Biomechanics¶

• The ankle joint is responsible for most sagittal plane motion of the foot and ankle [3].
• Ankle plantar flexion ranges from 23 to 48 degrees [3].
• Ankle dorsiflexion ranges from 10 to 23 degrees [3].
• The ankle joint also contributes to inversion, eversion, and rotation [3].
• A simplified model of the ankle joint has a horizontal axis from anteromedial to posterolateral [3].
• A simplified model of the ankle joint has a coronal axis from superomedial directed distally and laterally to the tip of the fibula [3].
• The deltoid ligament, specifically the tibiocalcaneal ligament, primarily prohibits eversion and abduction [8].
• The deep deltoid ligament, primarily the deep posterior tibiotalar ligament, resists external rotation when the foot is dorsiflexed [8].
• The deep deltoid ligament is responsible for the greatest restraint against lateral translation [8].
• Valgus tilting of the talus within the mortise requires complete rupture of both the superficial and deep deltoid ligaments [8].

Neurovascular Anatomy¶

• The superficial peroneal nerve penetrates the deep fascia and lies subcutaneously 8 to 10 cm proximal to the tip of the lateral malleolus, anterior to the subcutaneous border of the fibula shaft [6].
• The deep peroneal nerve accompanies the anterior tibial artery between the tendons of the anterior tibial and extensor digitorum longus muscles [6].
• The deep peroneal nerve lies just lateral to the anterior tibial artery and just lateral to the extensor hallucis longus tendon [6].
• The saphenous nerve is located just medial or posterior to the saphenous vein in a slightly deeper plane, 3 to 5 cm proximal to the tip of the medial malleolus [6].
• The anterior tibial artery can usually be palpated beneath the superior extensor retinaculum 4 to 5 cm proximal to the distal articular surface of the tibia [6].
• The peroneal tendons and superficial peroneal nerve are at the highest risk during intramedullary nailing of distal fibular fractures [11].
• An accessory incision for arthroscopic repair of the lateral ligament should not surpass 22 mm distance from the lateral malleolus in the anterior direction to avoid damaging the superficial peroneal nerve [11].

Fracture Classification¶

• The Danis–Weber Type A classification describes a transverse fracture of the fibula below the tibiofibular syndesmosis, sometimes associated with an oblique or vertical fracture of the medial malleolus [7].
• The Danis–Weber Type B classification describes an oblique fracture of the fibula in the sagittal plane at the level of the syndesmosis, often accompanied by an avulsion injury on the medial side [7].
• The Danis–Weber Type C classification describes a fracture above the level of the syndesmosis, indicating that the tibiofibular ligament and part of the interosseous membrane must have been torn [7].
• To achieve a reduced ankle, the fibula must be restored to its full length [7].
• To achieve a reduced ankle, the talus must sit squarely in the mortise with no tilt [7].
• To achieve a reduced ankle, the medial joint space must be restored to its normal width [7].
• To achieve a reduced ankle, there must be no tibiofibular diastasis [7].

Investigations¶

General Imaging Principles¶

• Advanced imaging is often helpful in diagnosis when combined with a thorough clinical examination [15].
• MRI is sensitive for all osteochondral lesions of the ankle, but the edema pattern frequently overestimates the severity of injury [12, 13].
• Linear fluid signal deep to subchondral bone on MRI indicates an unstable osteochondral injury [12, 13].
• MRI has a sensitivity of 92% for predicting stable versus unstable osteochondral lesions [12, 13].

Osteochondral Lesions¶

• Osteochondral lesions are seen in up to 70% of ankle sprains and 75% of ankle fractures [12, 13].
• The most common location for osteochondral lesions is the medial talar dome [12, 13].
• Modern data prove that the most common location for medial talar dome osteochondral lesions is central [12, 13].
• Medial talar dome osteochondral lesions are larger and deeper than lateral lesions [12, 13].
• The most common location for lateral talar dome osteochondral lesions is central [12, 13].
• Lateral talar dome osteochondral lesions are more often unstable, displaced, or symptomatic than medial lesions [12, 13].
• AP, mortise, and lateral weight-bearing ankle x-rays may not demonstrate subtle osteochondral lesions [12, 13].
• CT scan is helpful for determining the integrity of subchondral bone and identifying cysts in osteochondral lesions [12, 13].

Ankle Fractures and Syndesmosis¶

• MRI lacks additional diagnostic value for stability assessment of the ankle mortise in supination-external rotation-type ankle fractures [16].
• Preoperative computed tomography scans are used in operative planning for malleolar ankle fractures [16].
• Malreduction of the posterior malleolus is significantly more likely to lead to malreduction of the syndesmosis [16].

Ligamentous and Soft Tissue Pathology¶

• MRI is used for the evaluation of posterior tibial tendon dysfunction with relevance to clinical staging [1].
• MRI is used for the evaluation of anterolateral soft tissue impingement of the ankle [1, 17].
• MRI is used for the evaluation of osteochondral lesions of the talus [1].
• MRI is used for the diagnosis of ligamentous and chondral pathology in the ankle [1].
• MRI and stress radiography are used in the evaluation of chronic lateral ankle instability [1].
• MRI is used for pre-operative evaluation of the anterior talofibular ligament in chronic ankle instability [1].
• MRI findings are associated with symptoms in patients with chronic ankle sprain [1].
• MRI is used for the imaging evaluation of traumatic ligamentous injuries of the ankle and foot [1].
• MRI is used for the musculotendinous imaging of the ankle [1].
• CT and MR imaging are used for the evaluation of the postoperative ankle and foot [1].
• MRI is used for the diagnosis of plantar plate injury with reference to intraoperative findings [1].
• MRI is compared to physical examination for the diagnosis of syndesmotic injury after lateral ankle sprain [2].
• Peroneal tendon abnormalities are identified on routine magnetic resonance imaging of the foot and ankle [14].

Entrapment Neuropathies¶

• MR imaging is used for the evaluation of entrapment neuropathies of the lower extremity, including the knee, leg, ankle, and foot [18].
• Point-of-care ultrasonography is used in the diagnosis and management of superficial peroneal nerve entrapment [18].

References¶

[1] Campbell S Operative Orthopaedics 4 Volume Set. REFERENCES > FOOT AND ANKLE.

[2] Campbell S Operative Orthopaedics 4 Volume Set. REPAIR OF ACUTE RUPTURE OF LATERAL LIGAMENTS > ACUTE ANKLE LIGAMENT INJURIES, CHRONIC ANKLE INSTABILITY.

[3] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > BIOMECHANICS OF THE FOOT AND ANKLE.

[6] Campbell S Operative Orthopaedics 4 Volume Set. MULTIPLE Z-PLASTY RELEASE OF A CONGENITAL RING > ANKLE BLOCK.

[7] Apley And Solomon S Concise System Of Orthopaedics And Trauma. Treatment.

[8] Orthopaedic Knowledge Update Sports Medicine 6. Ankle and Foot Injuries and Other Disorders > Ankle Sprains > Medial Ankle Injury.

[11] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Foot and Ankle Anatomy and Biomechanics > Annotated References.

[12] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > OSTEOCHONDRAL LESIONS.

[13] Miller S Review Of Orthopaedics. OSTEOCHONDRAL LESIONS.

[14] Campbell S Operative Orthopaedics 4 Volume Set. MULTIPLE Z-PLASTY RELEASE OF A CONGENITAL RING > PERONEAL TENDONS.

[15] Orthopaedic Knowledge Update Sports Medicine 6. Ankle and Foot Injuries and Other Disorders > Summary.

[16] Orthopaedic Knowledge Update Trauma. Ankle Fractures > Annotated References.

[17] Campbell S Operative Orthopaedics 4 Volume Set. ARTHROSCOPIC EXAMINATION AND DEBRIDEMENT OF THE ANKLE JOINT > IMPINGEMENT.

[18] Campbell S Operative Orthopaedics 4 Volume Set. COMBINED HAMMER TOE AND MALLET TOE DEFORMITY WITH ASSOCIATED DOUBLE CORNS > REFERENCES > TARSAL TUNNEL SYNDROME.