Many treatment options are available for lower limb osteoarthritis. A patient can sometimes diminish symptoms simply by modifying activities. Switching from higher impact activities such as basketball to lower impact activities such as bicycling or swimming can decrease or eliminate joint pain.^83,¹⁴⁸ Ice, acetaminophen, and NSAIDs can all reduce joint pain. Glucosamine and chondroitin sulfate have shown mixed results for reducing pain in knee osteoarthritis.^82,^93,^125,^126,¹⁴⁵ Strength training and aerobic exercise can improve joint control and decrease pain.¹¹³ Strategies aimed at reducing loads on joints include weight loss, cushioned shoes, and walking aids such as a cane.¹⁵¹ Intraarticular injection of anesthetic and steroid can be helpful both diagnostically and therapeutically.^115,¹³⁹ Recent evidence shows that bupivacaine in concentrations 0.5% or more is chondrotoxic, and it would seem judicious to avoid its use in joint injections.³¹ Injections of the foot, ankle, and hip joints are best performed under fluoroscopic guidance with contrast confirmation. Several investigations looking at knee osteoarthritis have concluded that intraarticular injections of hyaluronate relieve pain and improve function in patients with mild and moderate knee osteoarthritis.^2,^63,^74,⁸⁶ For patients with recalcitrant pain or severe functional limitations, arthroplasty can provide substantial improvement in pain and function.

Stress Reactions and Stress Fractures in the Lower Limb

Repetitive overload injuries to the bones of the lower limb are common in physically active individuals, especially those who participate in endurance activities such as distance running. In cases of repetitive stress, or in the setting of impaired bone metabolism, bone strain occurs on a continuum from “stress response” or “stress reaction” to overt stress fracture. Bone overload can occur in any location in the lower limb (Figure 39-2). The ability of bone to withstand repetitive forces without breaking down depends on several factors. The stronger the bone is before being subjected to repetitive loading, the better it is able to withstand the loads applied to it. Both intrinsic and extrinsic factors are important to consider in determining the risk for stress reactions or stress fractures. Intrinsic risk factors include poor dietary habits, altered menstrual status, and biomechanical abnormalities that do not allow for proper distribution of forces along the kinetic chain. Extrinsic factors can include hard training surfaces, training errors, and improper footwear and insoles.

FIGURE 39-2 Examples of stress responses and stress fractures. A, T2-weighted, fat suppression, coronal magnetic resonance image of the legs shows increased signal in the medullary cavity of both tibiae (arrows), consistent with stress response or stress reaction. No discrete line indicates a stress fracture. The patient was a Division 1 cross-country runner with oligomenorrhea and disordered eating. B, T2-weighted, fat suppression MRI of the foot, showing increased signal in the calcaneus (arrow), consistent with a stress response. The patient was an Olympic freestyle skiing aerialist who had bilateral heel pain. The contralateral heel MRI had a similar appearance. T2-weighted, fat suppression, sagittal (C) (arrow) and T1-weighted, axial (D) MRIs showing a calcaneal stress fracture (arrow). The patient was a 29-year-old ultramarathoner.

Athletes report a greater frequency of disordered eating patterns than the general population, especially in sports emphasizing leanness.¹²¹ Individuals with disordered eating can have insufficient dietary intake of calories, protein, calcium, and other nutrients needed to achieve optimal bone quality. The triad of disordered eating, amenorrhea, and low bone density that occurs in athletic females is referred to as the female athlete triad. Restrictive eating behaviors increase the likelihood of stress fractures in women.^14,^15,^46,¹⁰⁵ Low caloric intake with negative protein balance has been hypothesized as one of the mechanisms for menstrual disturbances in female athletes.¹⁵⁵ Evidence shows that menstrual and hormonal disturbances increase the risk of stress fracture and lead to premature bone loss, particularly at trabecular sites.^64,¹⁰³

Flexibility, although difficult to study, can play a role in fracture risk. Some studies have suggested that increased hip external rotation and decreased ankle dorsiflexion might increase the risk for stress fractures in certain populations.^50,^51,⁶⁰

Skeletal alignment affects the amount of force absorbed by the foot, and how much force is transferred to proximal structures during ground contact. A rigid pes cavus foot is less able to absorb shock during and just after heel strike, and can transmit greater forces to proximal bones than a foot that is able to undergo normal pronation. Similarly, a pes planus foot does not allow the normal pronation mechanism to properly absorb forces. Either foot alignment can increase the risk of a stress fracture, the location of which can vary depending on the foot type and activity.^91,¹³⁴ Other studies looking at alignment have suggested that leg length discrepancy and increased Q angle can increase the risk of stress fracture.²⁷

Although it is clear that training errors contribute to stress fractures, there is limited research identifying the contribution of various training components. Furthermore, appropriate training regimens vary greatly among individuals. Athletes should be encouraged to keep training logs documenting type of training, volume, intensity, and rest periods. A rapid increase in training volume and intensity often precedes a stress fracture, just as it might precede a muscle–tendon overload injury. Articles about training in military recruits have shown that elimination of running and marching on concrete, preentry physical conditioning, and inclusion of rest periods reduced stress fracture risk.^54,^130,¹³¹

Shoes and insoles can be an important component in minimizing stress fracture risk. Proper shoe fit that matches an individual’s foot type, as well as adequate support and shock absorption, is essential. Studies looking at the effect of insoles or other footwear modifications on the prevention of stress fractures have shown a reduction in the number of stress fractures by more than 50%.^52,^96,⁹⁷

The patient presenting with a suspected stress fracture usually provides a history of a recent acceleration in the intensity or duration of training before the onset of symptoms. The patient most frequently complains of insidious onset of focal pain that is exacerbated with weight-bearing activities. In cases of certain stress fractures, such as femoral neck and navicular fractures, symptoms can be vague, thus increasing the time to diagnosis.

Imaging studies are not always necessary. A 6-week period of relative rest with nonimpact rehabilitation and alternative training methods such as pool running can be instituted. Imaging can be reserved for individuals who remain symptomatic and are unable to return to full activities. In these cases, or when definitive diagnosis is required sooner, the initial imaging study of choice is radiographs. It should be kept in mind, however, that plain films are relatively insensitive and detect less than 50% of stress fractures.^75,⁷⁶ When radiographs are normal but the suspicion for stress fracture remains high, advanced imaging studies are appropriate. Bone scans are sensitive for detecting stress fractures but lack anatomic definition. They can also remain positive long after symptoms have resolved. This limits the ability of bone scans to aid in return-to-sport decisions.¹³⁸ Magnetic resonance imaging (MRI) provides excellent anatomic information and can be more useful in grading lesions and assessing soft tissue structures.⁶ At our institution, MRI is the study of choice to look for stress fractures. Computed tomography (CT) provides optimal definition of bony architecture.

Multiple factors influence the length of time required to safely return to full activities after a stress fracture. These include duration of symptoms, stage of stress reaction, site of stress fracture, and level of activity or competition. Most stress fractures heal without complication with activity modification, and allow return to sport in 4 to 8 weeks with a few exceptions mentioned below.

Initial treatment includes pain management, activity modification, strengthening, fitness maintenance, and risk factor modification. Once healing is well underway and pain is minimal, the gradual resumption of the impact-loading phase of rehabilitation begins.

Pain can be a problem with lower limb stress fractures, mainly during weight-bearing. It might be appropriate to use crutches to minimize weight-bearing for the first 7 to 10 days. Modalities such as ice can also be helpful. Analgesics such as acetaminophen are appropriate. Some debate exists about the use of NSAID medications after a stress fracture. On a theoretical basis at least, the mode of action of these medications might prevent optimal repair of the stress fracture as a result of a reduction in the bone-remodeling process.

Activity modification includes eliminating impact activities for a period until daily ambulation is pain free. It is important to continue muscle strengthening and cross-training during this time, to keep the cardiopulmonary system fit.

Reduced muscle size and strength have been shown to predispose to stress fractures.⁵⁹ In endurance events, muscle fatigue can increase the strain on bone.¹⁵⁴ Muscle mass is important to build and maintain because the load placed on bone can be reduced at sites when muscles are better able to absorb repetitive impact.¹²⁹ A strengthening program should begin immediately after a diagnosis of stress fracture is made. The exercises prescribed should not cause pain at the fracture site.

Inactivity has negative consequences on the cardiovascular system, metabolism, and skeletal muscle after even brief periods of rest. It is important that fitness be maintained in ways that avoid overloading the bone. The most common cross-training activities include cycling, swimming, water running, rowing, and Stairmaster. The more sport specific the cross-training, the better the carryover effect of the training. It is for this reason that deep water running has become so popular among runners with stress fractures. Studies have shown no significant differences in maximal oxygen uptake, anaerobic threshold, running economy, stride length, and 2-mile performance after 4 to 8 weeks of land versus deep water running training.^38,^58,¹⁵³ In sports requiring specific skills, the neuromuscular adaptations are not easily duplicated with cross-training, and it is important to find appropriate ways to resume these isolated sport-specific skills as soon as possible.

When walking is pain free, the graduated impact phase of rehabilitation should progress on an individualized basis according to fracture site and symptoms. A progressive increase in load is necessary to allow bone to adapt with increases in strength. Resumption of activity should not be accompanied by pain, but it is not uncommon to have some mild discomfort at the fracture site. If bony pain occurs, then activity should be stopped for 1 to 2 days. When the individual is pain free while walking, the activity is resumed at a level before symptoms occurred. When training resumes, it is important to allow adequate recovery time after hard sessions or hard weeks of training. Progress should be monitored clinically by the presence or absence of symptoms and local signs. It is not necessary to monitor progress by imaging studies. Radiologic healing lags behind clinical healing.

Although most stress fractures heal without incident using the above treatment strategies, there are particular stress fractures that tend to develop complications and require specific treatment. These include stress fractures of the femoral neck, anterior cortex of the middle third of the tibia, navicular, and proximal fifth metatarsal fractures. These are discussed in their respective anatomic regions below. Stress fractures of the lower limbs are common and should be recognized and treated early to maximize successful outcome.

Conditions of the Hip Region

Femoral Neck Stress Fractures

With femoral neck stress fractures, symptoms are often vague, and one should have a high index of suspicion to catch this diagnosis early and avoid complications such as displacement or avascular necrosis. If suspicion is present, an MRI should be obtained (Figure 39-3). Fractures on the tension side (lateral) are less common and require immediate surgical referral. Fractures on the compression side (medial) are more common. If the fracture line extends more than 50% of the width of the femoral neck, percutaneous fixation should be considered because the likelihood of displacement is higher.^6,^32,¹³³ When the fracture line is less than 50% of the width of the femoral neck, strict non–weight-bearing status is necessary for about 4 to 6 weeks until the patient is pain free. This should be followed by functional rehabilitation with progressive weight-bearing over the next 4 to 8 weeks according to symptoms. If the athlete is not progressing as expected, additional radiologic evaluation should be considered.

FIGURE 39-3 T2-weighted, fat suppression, coronal magnetic resonance imaging of the pelvis, showing increased signal in the right femoral neck (arrow) consistent with stress fracture. The patient was an elite cross-country ski racer who had onset of symptoms after “bounding” exercises, which involve running uphill on one leg.

Avascular Necrosis

Avascular necrosis, also called osteonecrosis, is the death of bone resulting from a lack of blood supply. This can lead to microfractures and eventually collapse of the bone. The femoral head is the most commonly affected location. Disruption of the normal blood supply to the femoral head can be caused by various conditions including trauma, high doses of corticosteroids, alcohol abuse, and systemic illness (such as diabetes, lupus, and sickle cell anemia).⁸⁴ The severity of symptoms with avascular necrosis is usually related to the degree of articular surface disruption. Symptoms are similar to those experienced with hip osteoarthritis, including groin pain that increases with weight-bearing. Often there is limited motion and pain with internal rotation, flexion, and adduction of the hip. Radiographs can reveal sclerosis of the femoral head or, in severe cases, collapse of the femoral head (Figure 39-4). In mild cases, the plain films can be normal. MRI and CT can detect the condition in its earlier stages. Conservative treatment might include minimizing weight-bearing of the affected joint and use of pain medications. Once collapse occurs, joint replacement surgery is indicated.

FIGURE 39-4 Anteroposterior radiograph of the pelvis, showing advanced avascular necrosis of both femoral heads.

Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes disease is idiopathic osteonecrosis of the femoral head in children. It occurs most frequently in boys between the ages of 4 and 8 years. Because bone repair is relatively rapid in children, the prognosis is significantly better compared with adults with avascular necrosis. Signs of Legg-Calvé-Perthes disease in a child include limping and restriction in hip motion, especially hip abduction. The child might complain of groin or thigh pain. Healing can occur in children with revascularization of the femoral head and remodeling of the bone. The prognosis is better in younger children and those with milder involvement. In children under the age of 6 years, observation and use of an abduction brace to maintain the femoral head in a spherical state is reasonable. Osteotomy is sometimes performed in older children.⁸⁵

Slipped Capital Femoral Epiphysis

The most common hip disorder in adolescents is slipped capital femoral epiphysis. Injury to the physeal plate of the proximal femur with medial displacement of the femoral head relative to the femoral shaft can be due to acute trauma or repetitive microtrauma. Slipped capital femoral epiphysis is rare in boys under age 11 years and girls under age 9 years, and is more common in overweight boys.⁸⁵ There can be an association with hypothyroidism and renal osteodystrophy.⁴⁸ Slipped capital femoral epiphysis is bilateral about 50% of the time.⁸⁵ An adolescent with an acute slip typically presents with severe hip pain that is exacerbated with any motion. The individual tends to hold the hip flexed and externally rotated. Anteroposterior and lateral radiographs confirm the diagnosis(Figure 39-5). A mild slip can be treated conservatively.¹²⁷ Otherwise, one attempt at closed reduction can be done. If this is unsuccessful, open reduction should be done. After reduction, gentle range of motion can be started within a few days, but weight-bearing is restricted for 4 to 6 weeks.¹²⁷ After this period, gradually progressive strengthening and functional exercises can be advanced. Complications include nonunion, avascular necrosis of the femoral head, rotational deformity, and osteoarthritis.^85,¹³⁷

FIGURE 39-5 Anteroposterior radiograph of a severe, acute slipped capital femoral epiphysis.

Hip Dislocation

Because of the depth of the acetabulum, dislocation of the femoral–acetabular joint requires significant trauma. In children, hip dislocation is more common than hip fractures. In adults, fractures of the acetabulum often accompany hip dislocations. Most commonly, the head of the femur dislocates posteriorly relative to the acetabulum.¹⁰² The patient with an acute posterior hip dislocation presents with severe hip pain and tends to hold the hip in flexion, internal rotation, and adduction. With the less common anterior dislocations, the hip is held in an extended, abducted, and externally rotated position.

On physical examination, there will be an obvious deformity. The patient will not tolerate range of motion or resistance testing because of pain. A complete neurologic examination should be performed to assess for lumbosacral plexopathy, sciatic neuropathy, and femoral neuropathy.⁹² One should always assess for associated injuries, in particular spine and ipsilateral knee trauma, which can be masked by hip pain. Radiographs are indicated to confirm the clinical diagnosis and look for associated injuries. Hip dislocations are an orthopedic emergency, and closed reduction under anesthesia should be performed as soon as possible. Postreduction radiographs are obtained to confirm anatomic alignment. At times, CT or MRI is obtained if further characterization of associated injuries is needed.

Surgery is indicated if attempts at closed reduction are unsuccessful. The surgical goals are to repair displaced or comminuted fractures and remove intraarticular loose bodies.³⁶ Most clinicians recommend non–weight-bearing for 3 to 4 weeks, followed by protected weight-bearing for an additional 3 weeks.¹²⁷ Gradually progressive rehabilitation can start a few days to a couple of weeks after reduction, depending on the patient’s comfort level and whether surgery was performed. The most concerning complications of hip dislocation include posttraumatic osteoarthritis and avascular necrosis, which occurs in up to 10% of patients.¹³⁷ The risk of avascular necrosis increases with age, reduction delayed greater than 6 hours, and more severe trauma to the hip joint.

Labral Injuries

Acetabular labral tears are analogous to glenoid labral tears, with some notable exceptions. Patients with acetabular labral tears often present with painful catching of the hip, especially when the hip is at a particular angle.⁹⁰ There might be a clear history of acute or repetitive trauma. Femoral–acetabular grind maneuvers might reproduce symptoms. Historical features and physical examination maneuvers are even less specific for acetabular labral tears than they are for glenoid labral tears. This might be because the hip is a larger, deeper joint with less sensitive innervation than the shoulder joint. Magnetic resonance arthrography with gadolinium contrast is the imaging study of choice to assess for these injuries (Figure 39-6). Definitive diagnosis is by arthroscopy or open surgery.

FIGURE 39-6 Gadolinium-enhanced sagittal magnetic resonance image of the hip, showing an anterior labral tear.

Treatments can include acetaminophen or NSAIDs, relative rest, intraarticular steroid injections, and surgical debridement or repair. The arthroscopic and open surgical approaches to labral injuries of the hip continue to evolve.^20,^21,^39,⁶⁹

Conditions of the Thigh Region

Disorders of the Iliotibial Band, Including Trochanteric Bursitis

The iliotibial band (ITB) is a strong fascial band that runs along the lateral aspect of the thigh from the level of the greater trochanter to the proximal, anterolateral tibia (Figure 39-8). ITB motion is controlled proximally primarily by the gluteus maximus and tensor fascia lata, the two muscles that insert into it. The ITB inserts distally onto a bony prominence at the proximal, anterolateral tibia called Gerdy’s tubercle. Therefore the ITB can exert forces at the hip and knee. Conversely, alterations in various lower limb mechanics, such as genu valgum, pes planus, and tibial internal or external rotation, can affect ITB function. Three clinically important bursae are related to the ITB.¹¹² The proximal bursa is positioned to decrease friction between the ITB and the greater trochanter of the femur. Another site of potential friction is where the ITB runs over the lateral epicondyle of the femur.¹⁸ The third lies at the ITB’s distal attachment on the tibia.