The Foot and Industrial Consequences of Injury - Part 2

Sunday, January 16, 2005 | 0

This is the second article in a series of four by foot and ankle specialist, Dr. Jodi Schoenhaus. The first article contained facts about the human foot and possible ailments due to work-related injuries. This article reviews facts about the human ankle. Earlier articles can be accessed by clicking on the title in the right side bar.

Part Two: Facts about the Human Ankle

The most common injury sustained by the ankle is the ankle sprain. It is the number one ankle related injury in any hospital emergency department. There are varying degrees of severity of ankle sprains that must be appropriately managed in order to restore function of the ankle joint.

The most commonly injured ligament, and the first to fail in a lateral ankle injury is the anterior talofibular ligament (ATFL). If this is injured alone it is considered Grade I. This connects the talus bone to the fibula and aids in resisting ankle inversion injuries. After the ATFL ruptures the next ligament to be sacrificed is the calcaneal fibular ligament (CFL). It originates at the lateral fibula and fans out distally to the calcaneus, crossing two joints. This too resists inversion. Ankle sprains involving the ATFL and CFL are considered Grade II and are more debilitating that a Grade I injury.

Most Grade I and II sprains are treated conservatively, however, there is a percentage of Grade II sprains with complete rupture that need to be surgically corrected. Finally, the posterior talofibular ligament (PTFL) connects the posterior aspect of talus and fibula. This is the strongest collateral ligament and rupture of this structure is rare. When this injury occurs, it is considered a Grade III sprain. Grade III sprains will require surgical intervention.

The medial ankle structures are called the deltoid ligaments. There are a total of four and they connect the tibia with the talus and the navicular. This intricate complex of ankle ligaments resists ankle eversion. It is an extremely strong ligament complex and rupture is unlikely. When there is injury to the medial aspect of the ankle involving the ligaments, there is more often a medial malleolar avulsion fracture of the tibia bone. Fracture care will be discussed later in this series of articles.

A high ankle sprain is an injury to the tibiofibular ligament. This is often a missed diagnosis and can lead to chronic pain and arthritis. This diagnosis is usually made by clinical examination with pain at the tibiofibular syndesmosis above the level of the ankle joint. There is pain with compression of the leg bones above the level of the ankle as well as pain with external rotation of the foot on the leg, while the foot is dorsiflexed and the knee is flexed. A CT scan can be used and comparing the proximal and distal syndesmosis (articulation) reveals a diastasis (separation) of the distal articulation of the tibia and fibula.

Proper rest and immobilization is needed to appropriately heal this injury. If treated incorrectly, the patient will return to work and have continued ankle pain, which then needs surgical debridement and utilization of a screw to allow for healing.

Diagnosis of ankle ligament injuries is usually a clinical diagnosis. Fractures and dislocations are negative on radiographic imaging studies and the patient does not have pain or palpation directly over the bony structures of the lower leg. The patient does present with ecchymosis, edema, and pain.

MRI studies are not pertinent to identify torn ligaments, however a commonly missed injury associated with severe ankle sprains is an osteochondral defect of the talus. This is a tear of the cartilage and possible fracture of the talus on the surface of the ankle joint that can lead to chronic pain and arthritis if it is not appropriately diagnosed and treated.

Treatment for osteochondral lesions of the talus consists of casting and immobilization for three to six weeks, if minor. Larger defects may require arthroscopic surgery to debride the defect and allow for fibrocartilage ingrowth. The larger defects and osteochondral lesions that are difficult to reach through an arthroscope may require opening of the ankle joint and replacement of the actual defect with graft. In these cases, one can expect extensive ankle surgery, immobilization or six to twelve weeks and a course of physical therapy for another ten to twelve weeks with a work hardening program.

Ankle fractures are common injuries that usually require casting and immobilization. Some fractures can be closed reduced by manipulation in an office or emergency department and then casted. If a fracture is displaced, open reduction with internal fixation to include screws and plates is warranted. Regardless of the reduction, for adequate healing of bone to occur, six to eight weeks of nonweight bearing or weight bearing in a cast followed by physical therapy is needed.

Diagnosis of ankle fractures is made by a combination of clinical examination and radiographs. Most fractures are noted on radiographic imaging studies. However, stress fractures, which are considered overuse injuries, can occur in the foot as well as the fibula and tibia, albeit less often, and are not immediately seen on x-ray. The presence is noted after 30-50% of bone resorption occurs, approximately 7-10 days. A patient will complain of pain, usually at night and with activity, and swelling. A nuclear bone scan, Tc99 study, is usually ordered to confirm this diagnosis. Treatment for this condition is a walking cast for four weeks along with a short course of physical therapy.

The next article in this series will discuss common foot and ankle work-related injuries.

Contributed by foot and ankle specialist, Dr. Jodi Schoenhaus of Total Orthopaedic Care, Ft. Lauderdale, FL. Dr. Schoenhaus can be reached at 954-735-3535.

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