13 Lower Leg Problems EDWARD J. S HAHADY This chapter covers primary care problems that occur between the ankles and the knees. Many common lower leg problems will be encountered by the pri- mary care practitioner. Most patients seen with lower leg pain are physically active and their pain is related to exercise. Direct trauma and neurovascular disease can be associated with lower leg pain. Overuse is the cause of most of the problems in active patients, with shin splints topping the list. Shin splints are a waste-basket term and a more specific diagnosis like medial tibial stress syndrome (MTSS) or tibial stress fracture should be sought. Direct trauma may lead to a fracture or significant contusion. Spinal stenosis (see Chapter 10), osteoarthritis of the hip (see Chapter 11), and iliotibial band syndrome (see Chapter 12) can all refer pain to the lower leg and exercise can make the pain in all these entities worse. As with all musculoskeletal problems, a good working knowledge of the epidemiology, anatomy, associated symptoms, and examination reduce con- fusion and enhance the diagnostic and therapeutic process. Caring for problems is easier if a few simple organizational steps are fol- lowed: 1. Step 1 is to realize that the majority (95%) of patients seen in the office with lower leg complaints can be classified into the categories of problems noted in Table 13.1. 2. Step 2 is to take a focused history that segments the categories into acute trauma, overuse trauma, and medical disease. This process reduces the possibilities to a manageable list that helps initiate further investigation. 3. Step 3, performing a focused physical examination, builds on the detective work of the first two steps. With a focused history and examination, you now most likely have a potential diagnosis. Your knowledge of the usual history and examination associated with the most common problems has facilitated this process. 4. Step 4 is ordering confirmatory studies if needed (many times they are not). 5. Step 5 is to start treatment. (This may include appropriate consultation.) Five percent of the time, the diagnosis will not be so obvious. However, not being one of the 95% is usually obvious. That is when additional con- firmatory studies and/or a consultation will be required. 13. Lower Leg Problems 269 TABLE 13.1. Classification of lower leg problems. Overuse Medial tibial stress syndrome Stress fractures Compartment syndromes Gastrocnemius tears Popliteus tendonitis Retrocalcaneal bursitis Achilles tendonitis and rupture Acute trauma Fracture of the tibia Fracture of the fibula Medical problems Spinal stenosis Rare or not so frequent problems are usually the ones that receive the most press. How often do you hear the words “I got burned once” mentioned about a rare problem that was missed in the primary care setting. Having a good working knowledge of the characteristics of common problems provides an excellent background to help recognize the uncommon. The uncommon is easy to recognize once you know the common. Be driven by the search for the common rather than the expensive intimidating search for the rare birds. 1. Anatomy The two major bones of the lower leg are the tibia and fibula. They are con- nected by a superior and inferior tibiofibular joint and an interosseous mem- brane. The interosseous membrane is most important at its distal portion because it keeps the two bones together and helps provide for a stable ankle mortise. Disruption of the membrane distally leads to ankle joint dysfunc- tion. This is discussed in Chapter 14. The lower leg is divided into anterior, lateral, superficial posterior, and deep posterior compartments. Figures 13.1 and 13.2 describe the compart- ments and the contents of the compartments. Knowledge of the structures in these compartments aids in the diagnosis and treatment of lower leg prob- lems. The anterior compartment contains the tibialis anterior, the long toe extensor muscles, the deep peroneal nerve, and the anterior tibial artery. The nerve supplies sensation to the first web space of the foot and the muscles are responsible for dorsiflexion of the foot. The lateral compartment contains the peroneus longus and brevis and the superficial peroneal nerve. These two muscles evert the foot and the nerve supplies sensation to the dorsum of the foot. The posterior compartment of the leg is divided into superficial and deep compartments. The superficial compartment contains the gastrocne- mius, plantaris, and soleus muscles and the sural nerve. The muscles aid in 270 E.J. Shahady Tibia Anterior Lateral Deep Posterior Superficial Posterior Fibula FIGURE 13.1. Compartments of the lower leg. plantar flexion and the nerve supplies the lateral side of the foot and the dis- tal calf. The deep posterior compartment contains the tibialis posterior mus- cle, the long toe flexor muscles, the posterior tibial and peroneal arteries, and the tibial nerve. The muscles aid in plantar flexion and eversion and the nerve supplies sensory function to the plantar aspect of the foot. The popliteal artery provides the vascular supply to the lower leg. The artery divides to form three branches: the anterior tibial artery, the posterior tibial artery, and Tibialis anterior & Foot extensor muscles, Tibia Deep personeal nerve, Anterior tibial artery Tibialis posterior & foot flexor Peroneus muscles longus and posterior brevis tibial and muscles, personeal arteries, tibial nerve. Fibula Gastrocnemius, and soleus muscles FIGURE 13.2. Anatomical structures in lower leg. 13. Lower Leg Problems 271 the peroneal artery. Palpating the dorsalis pedis artery over the dorsum of the foot assesses the anterior tibial artery. The posterior tibial artery is palpated posterior to the medial malleolus. 2. Focused History Establish whether the problem is acute or chronic or if other chronic diseases that have musculoskeletal components are present. This will get you started down the right path. The mechanism of injury will many times pinpoint the anatomy involved in the injury. Questions like the following help put the pieces of the puzzle together: Was there a direct blow to the leg like being kicked in soccer or football? If the problem is chronic and getting worse ask how it is related to exercise. Is it only present with exercise? Does it stop or continue after exercise is over? Certain characteristics like intensifying one’s exercise routine, changing the terrain like hills or the beach, or a change of shoes are all areas that may be causative in the overuse syndrome. Be alert for symptoms of neurological or vascular compromise. Compartment syn- dromes can produce neurological symptoms like numbness and/or a foot drop. Spinal stenosis can produce a burning pain and weakness of foot move- ment secondary to nerve root compression. A good working knowledge of lower leg anatomy as outlined above will help you understand what structures were involved when the injury occurred. Do not forget to ask about other medical problems. Patients with osteoarthritis usually have evidence of other signs of osteoarthritis in the hands (Heberden’s nodes). Rheumatoid arthritis commonly involves the ankle and foot and the first signs of rheumatoid may be in the foot and ankle. 3. Focused Physical Examination Begin by comparing the injured leg with the uninjured one. Look for ery- thema, swelling, and atrophy of the musculature. Have the patient walk with- out shoes and socks and observe from behind for pronation. Pronation is excessive eversion (Figure 13.3). Ask the patient to point with one finger to the site of the pain. Pinpoint pain is more characteristic of fractures and more dif- fuse pain suggests MTSS. Location of the pain is also diagnostic, as will be pointed out when specific problems are discussed. Use a tuning fork above the area of pain to see if the vibrations reproduce the patient’s pain. The tuning fork test helps diagnose stress fractures. Hopping up and down on the foot of the involved leg is usually painful in tibial stress fractures. Plantar flexion aggravates the pain of the MTSS and posterior tibial tendonitis. Dorsiflexion aggravates the pain of anterior tibial tendonitis. Anterior and posterior tibial tendonitis cause pain to the foot, so they will be discussed in Chapter 15. 272 E.J. Shahady FIGURE 13.3. Eversion–pronation. 4. Case 4.1. History A 17-year-old boy presents to your office with left lower leg pain of 3-week duration. He began football practice 3 weeks ago. The pain initially was pres- ent at the end of practice and quickly disappeared. It now is present as soon as he starts practice and it increases in intensity to the point he cannot con- tinue to practice after 1 h. The pain persists for 1 to 2 h after practice. He does not note any numbness or loss of ability to move his foot. He did not stay in shape over the summer, so he was not well-conditioned at the start of prac- tice. Examination reveals no gross difference in the appearance of the lower extremity. He does pronate when he walks. He points to a general area on his posterior medial tibia that is painful (Figure 13.4). The tuning fork test is negative. Resisted plantar flexion and standing on his tiptoes on the left reproduces the pain. He has no neurological deficit. His shoes are 2 years old and were used by his brother for a full season. They provide minimal support medially and the cleats are worn out on the medial side. 13. Lower Leg Problems 273 FIGURE 13.4. Location of pain in medial tibial stress syndrome. 4.2. Thinking Process This is most likely an overuse injury given the patient’s age, lack of acute trauma, gradual onset of symptoms, and recent onset of intense physical activity.