Stress fractures of the lower extremities are a recognized risk of intense physical activity (eg, sports training or military service). Although femoral stress fractures represent only 3% to 21% of stress fractures experienced by athletes, their sequelae can have grave consequences.1-3 Although rare, a more serious risk is that of fracture displacement with comminution. The displaced femoral shaft stress fracture frequently requires open reduction and internal fixation, which carries the risk of prolonged morbidity and possible complications.4 Most patients with displaced femoral stress fractures experience symptoms of thigh or knee pain on weight bearing prior to complete fracture and displacement.4 Such symptoms should trigger a radiographic workup, including a bone scan or magnetic resonance imaging (MRI) to diagnose a stress fracture prior to displacement. This article describes a case of an adolescent athlete with bilateral femoral stress fractures, one of which was displaced at presentation and required surgical treatment. To the best of our knowledge, this is the first reported case of complete and incomplete femoral stress fractures in a pediatric patient.
A healthy 15-year-old male athlete was evaluated in the emergency department after transfer from an outside hospital for treatment of a right-sided femoral fracture that occurred following direct trauma during a high school lacrosse game. The patient reported being struck by 2 opposing players and felt a snap in his leg as he fell to the ground. The patient’s history included a contralateral tibial stress fracture 4 years earlier and intermittent bilateral shin splints that caused him to curtail his athletic activity and withdraw from the cross country team earlier in the school year. Notably, the patient had reported bilateral knee pain occurring with markedly increased levels of physical activity at the beginning of training for the lacrosse season 2 months prior to injury. The patient had been evaluated as an outpatient by a nonoperative sports medicine physician who had ordered bilateral knee radiographs that were read as normal. At that time, the patient was diagnosed with bilateral quadriceps tendonitis. Although he was not prescribed a formal physical therapy program, he was given instructions for a home exercise program. The patient was cautioned to limit his sprinting, but returned to play without other restrictions. The patient reported that he was free of knee pain for 4 days prior to the injury.
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|Figure 1: AP (A) and lateral (B) radiographs of the right thigh obtained on presentation illustrating a displaced right femoral stress fracture. |
Upon examination, the right knee and thigh were markedly tender and swollen. The patient had a normal neurologic and vascular examination. Anteroposterior and lateral radiographs were taken of the femur and knee, and the patient was diagnosed with a transverse femoral supracondylar fracture (Figure 1). The radiographs revealed periosteal reaction along the right lateral femoral cortex and a variable appearance of the right metaphyseal femoral fracture. Given the mechanism of injury for the fracture and the appearance on plain radiographs, the patient was evaluated for a possible pathologic fracture. A triple phase bone scan revealed increased uptake at the fracture site of the right femur and increased uptake in the left distal femur (Figure 2). Subsequent plain radiographs of the contralateral femur were remarkable for a nearly identical pattern of periosteal reaction in the supracondylar region of the femur in addition to a sclerotic line corresponding to the fracture site on the injured side (Figure 3). Magnetic resonance imaging revealed a right displaced femoral fracture with hematoma formation. The study was unremarkable for other pathologic soft tissue or bone masses (Figure 4). Hematology and blood chemistry were normal.
|Figure 2: Full body and thigh views of triple phase bone scan demonstrating bilateral distal femoral involvement. |
Treatment strategies using either crossed Kirschner wire fixation or flexible intramedullary nailing were considered. Due to the location and severity of the fracture and the contralateral stress fracture, intramedullary nailing was selected. The benefits of intramedullary nailing over K-wire fixation in this case included stronger fixation with decreased need for immobilization and faster return to weight bearing. Because the patient was approaching skeletal maturity, the risk of physeal damage from intramedullary nailing was considered acceptable given the potential benefits of the procedure. Open reduction and internal fixation of the right displaced femoral fracture was performed. The fracture was reduced and stabilized with a retrograde locked intramedullary nail (Smith & Nephew Inc., Memphis, Tennessee; Figure 5). The patient underwent an uneventful postoperative course. The left nondisplaced stress fracture was treated conservatively with limitation of weight bearing.
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|Figure 3: AP (A) and lateral (B) radiographs of the left thigh obtained on presentation illustrating a nondisplaced left femoral stress fracture. |
The patient was placed on toe touch weight bearing of his right lower extremity for 1 week and was then sent to a formal physical therapy program with advancement to weight bearing as tolerated for 6 weeks. At 2 months postoperatively, the patient’s motion was 0° to 70° for the right knee, and appropriate callous formation was noted. Because the patient did not gain motion after another 3.5 weeks, he underwent arthroscopic lysis of adhesions from the suprapatellar pouch and the medial and lateral gutters, hardware removal, and manipulation under anesthesia. Postoperatively, his motion improved to 0° to 125° for the right knee. He was given a continuous passive motion machine and participated in an intensive inpatient (followed by outpatient) range of motion program, which resulted in short-term maintenance of range of motion and an increase to 0° to 140° for the right knee 4 months after the index surgery. He advanced to swimming and biking but avoided contact sports until 6 months from the date of his injury. Nine months postinjury, he had symmetric strength and range of motion in his lower extremities with significant bone remodeling, in addition to complete healing.
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|Figure 4: Sagital T2-weighted MRI of the right distal femur illustrating the displaced right femoral stress fracture. Figure 5: AP (A) and lateral (B) radiographs of the right thigh status following open reduction and internal fixation of a right displaced femoral stress fracture using a retrograde locked intramedullary nail. |
Femoral stress fractures represent a small subset of stress fractures. In a series of 320 athletes with stress fractures, 49.1% had fractures of the tibia, 25.3% had fractures of the tarsals, 8.8% had fractures of the metatarsals and 7.2% had fractures of the femur.5 Running represents the activity most frequently associated with stress fractures of any bone accounting for 69% to 72% of cases in several studies.5,6 In the military setting, women are at greater risk of stress fracture than men; however, this difference has not been demonstrated in an athletic population.7,8
A rapid increase in activity intensity, frequency, and duration are well-known risk factors for stress fractures. Johnson et al1 reported that 6 of 8 athletes sustaining femoral stress fractures had recently increased their activities, and Clement et al9 reported recent increases in activity in 30% of femoral stress fractures. The athlete in this case had experienced the onset of bilateral knee pain shortly after the onset of training with the start of lacrosse season.
The difficulty of diagnosis for femoral stress fractures is well documented. One study of stress fractures in athletes found that femoral fractures had the lowest incidence of detectable swelling or tenderness.5 Additionally, any pain that does occur may be poorly localized.1 One study of 74 femoral stress fractures found that the most common site of pain was the anterior thigh, followed by the hip, and then the groin.9 The pain from femoral stress fractures is exacerbated by progressive training and typically is relieved by rest.4,10 Additionally, pain resulting from stress fracture often is attributed to soft tissue injury due to its vague and diffuse distribution.10 In the current case, the symptom reported prior to displacement was nonspecific knee pain which was attributed to bilateral knee tendonitis.
Specific physical examination techniques have been designed to facilitate the diagnosis of femoral stress fracture. Clement et al9 found that asking the patient to hop one-legged on the affected limb caused hip, groin, or anterior thigh pain in 70.3% of patients with femoral stress fractures. Johnson et al1 described the fulcrum technique, which involves applying downward pressure on the knee while the examiner moves his or her arm proximally to distally under the patient’s thigh. This technique produces sharp pain and apprehension in patients with femoral stress fractures. Percussion on the involved bone may also produce pain as the force is transmitted to the fracture site.11
Plain film radiographs have poor sensitivity in the diagnosis of femoral stress fractures. In one study of femoral stress fractures, only 24% of plain radiographs showed abnormality.9 The limitations of conventional radiographs make other imaging studies necessary in the evaluation of a potential stress fracture. Triple phase bone scan can differentiate between soft tissue and osseous injuries as well as chronic and acute stress fractures as early as 6 to 72 hours after injury.5 A negative bone scan effectively rules out stress fracture.12 Alternately, MRI can detect stress fractures. In addition to delineating the fracture pattern, this study can provide soft tissue detail in the fracture area.12 Arendt and Griffiths13 found MRI to have a higher predictive value for estimating the duration of disability for patients with stress fractures. They recommend MRI in any athlete with a possible stress fracture despite negative plain films.
Treatment of a femoral stress fracture is dependent on the presence of displacement. Hershman et al10 found conservative treatment of nondisplaced femoral stress fractures to be highly successful, with the majority of athletes able to return to activity after 8 to 14 weeks of rest. Tuan et al14 suggested that most stress fractures can be managed with cessation of the causative activity, allowing for new bone formation and healing. Clement15 described a treatment regimen consisting of 2 phases. Phase 1 in his protocol involved a period of modified rest including weight bearing in daily activities but elimination of the offending activity. Phase 2 was initiated when the athlete had been pain free for 10 to 14 days, and involved a gradual return sports. During phase 2, pain was used as a guide for the rate of sport reintroduction. Physical examination techniques as described above can also be used to monitor healing progress.1
Displaced femoral stress fractures generally require surgical treatment. Surgical options include treatment with an intramedullary nail or nails, plate and screw constructs, fixed-angle devices, or external fixators. In the present case, fixation was obtained with a retrograde locked intramedullary nail.
Given the vague symptoms associated with femoral stress fractures, a high index of suspicion is necessary for diagnosis. An appropriate workup, including a complete history closely correlating pain and activity level, a physical examination using several of the unique tests described, and further imaging studies (eg, bone scan or MRI) must be initiated expeditiously. Although perhaps not always possible, every attempt at early detection should be made. Early detection is of great importance due to the effective conservative treatments available for nondisplaced stress fractures and the morbidity of fracture displacement and surgical treatment.
- Johnson AW, Weiss CB Jr, Wheeler DL. Stress fractures of the femoral shaft in athletes–more common than expected. A new clinical test. Am J Sports Med. 1994; 22(2):248-256.
- Orava S, Puranen J, Ala-Ketola L. Stress fractures caused by physical exercise. Acta Orthop Scand. 1978; 49(1):19-27.
- McBryde AM Jr. Stress fractures in runners. Clin Sports Med. 1985; 4(4):737-752.
- Salminen ST, Pihlajamaki HK, Visuri TI, Bostman OM. Displaced fatigue fractures of the femoral shaft. Clin Orthop Relat Res. 2003; (409):250-259.
- Matheson GO, Clement DB, McKenzie DC, Taunton JE, Lloyd-Smith DR, MacIntyre JG. Stress fractures in athletes. A study of 320 cases. Am J Sports Med. 1987; 15(1):46-58.
- Hulkko A, Orava S. Stress fractures in athletes. Int J Sports Med. 1987; 8(3):221-226.
- Protzman RR, Griffis CG. Stress fractures in men and women undergoing military training. J Bone Joint Surg Am. 1977; 59(6):825.
- Bennell KL, Malcolm SA, Thomas SA, Wark JD, Brukner PD. The incidence and distribution of stress fractures in competitive track and field athletes. A twelve-month prospective study. Am J Sports Med. 1996; 24(2):211-217.
- Clement DB, Ammann W, Taunton JE, et al. Exercise-induced stress injuries to the femur. Int J Sports Med. 1993; 14(6):347-352.
- Hershman EB, Lombardo J, Bergfeld JA. Femoral shaft stress fractures in athletes. Clin Sports Med. 1990; 9(1):111-119.
- Knapp TP, Garrett WE Jr. Stress fractures: general concepts. Clin Sports Med. 1997; 16(2):339-356.
- Perron AD, Brady WJ, Keats TA. Principles of stress fracture management. The whys and hows of an increasingly common injury. Postgrad Med. 2001; 110(3):115-118, 123-114.
- Arendt EA, Griffiths HJ. The use of MR imaging in the assessment and clinical management of stress reactions of bone in high-performance athletes. Clin Sports Med. 1997; 16(2):291-306.
- Tuan K, Wu S, Sennett B. Stress fractures in athletes: risk factors, diagnosis, and management. Orthopedics. 2004; 27(6):583-591
- Clement DB. Tibial stress syndrome in athletes. J Sports Med. 1974; 2(2):81-85.
Dr Hutchinson is from the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania; Dr Stieber is from the Department of Orthopedic Surgery, St. Luke’s-Roosevelt Hospital, New York, New York; Drs Flynn and Ganley are from the Department of Orthopedic Surgery, Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.
Drs Hutchinson, Stieber, Flynn, and Ganley have no relevant financial relationships to disclose.
Correspondence should be addressed to: Peter H. Hutchinson, MD, 1090 Beacon St, Apt 2A, Brookline, MA 02446.