Femoral Neck Stress Fractures Joshua David Harris, MD, and Jaskarndip Chahal, MD, FRCSC, MSc Stress fractures are common overuse injuries in the lower extremities that occur with either abnormal stress on normal bone (fatigue fracture) or normal stress on abnormal bone (insufficiency fracture). Location of a stress fracture and associated potential for delayed union, nonunion, and refracture facilitate designation of a fracture as either “high risk” or “low risk.” Femoral neck stress fractures account for less than 5% of all stress fractures. Based on the biomechanics of the proximal femur, these fractures may be on the inferomedial compression side or the superolateral tension side. Tension-side fractures are of “high risk” and compression-side fractures are of “low risk.” Once a diagnosis of stress fracture is made, a thorough evaluation for modifiable endocrinologic and nutritional risk factors is undertaken and a treatment and prevention program commenced. Nonsurgical treatment with crutchassisted non weight bearing ambulation is indicated for incomplete compression-side fractures. Surgical treatment is indicated for (1) complete fracture with or without displacement, (2) tension-sided incomplete fractures, and (3) compression-sided incomplete fractures that have failed nonsurgical treatment for a minimum of 6 weeks. Percutaneous screw fixation with 6.5- or 7.3-mm screws is the standard of care for surgical treatment. Stress fracture displacement requires urgent anatomical reduction. Thus, if a closed reduction is unable to be achieved under anesthesia, then an anterior Smith-Petersen approach is necessary to anatomically reduce and fix the fracture. Postoperatively, following percutaneous screw fixation of a nondisplaced stress fracture, patients may begin weight bearing as tolerated. Complications include displacement, nonunion, delayed union, varus malunion, and avascular necrosis. Oper Tech Sports Med 23:241-247 C 2015 Elsevier Inc. All rights reserved.
KEYWORDS stress fracture, hip, femoral neck, overuse injury
Introduction
S
nonunion, and avascular necrosis if displaced. Thus, surgical treatment is the standard of care for tension-sided injuries. Compression-side femoral neck stress fractures are considered to be of “low risk” owing to the biomechanics of the medial femoral neck and their higher likelihood for healing with nonsurgical treatment with non weight bearing crutchassisted gait. In the initial and all follow-up evaluations, risk factors for femoral neck stress fracture (Table 1) must be identified, treated, and prevented.
tress fractures are common overuse injuries in the lower extremities. Repetitive episodes of high-intensity or extended-duration axial load to the leg places the bone at risk of stress-related injury. The femoral neck is an uncommon location for stress fracture (less than 5% of all stress fractures). Stress fracture evaluation and management begins with a thorough history, physical examination, and radiographic examination. Fracture location, type, and grade permits generic dichotomized classification of “low-risk” and “high-risk” fractures. Tension-side femoral neck stress fractures are considered “high-risk” because of their potential for displacement,
Stress Fracture Pathophysiology
Orthopedic Surgery, Houston Methodist Orthopedics & Sports Medicine, Houston, TX. Address reprint requests to Joshua David Harris, Houston Methodist Orthopedics & Sports Medicine, 6550 Fannin St, Smith Tower, Ste. 2600 Suite 400, Houston, TX 77030. E-mail:
[email protected]
Stress fractures are common overuse injuries in the lower extremities. Generally speaking, stress fractures occur with abnormal stress on normal bone (fatigue fracture) or with normal stress on abnormal bone (insufficiency fracture). Repeated bouts of high-intensity or extended-duration load to the bone may place individuals at risk for stress fracture.1
http://dx.doi.org/10.1053/j.otsm.2015.07.001 1060-1872//& 2015 Elsevier Inc. All rights reserved.
241
J.D. Harris and J. Chahal
242 Table 1 Risk Factors For Femoral Neck Stress Fracture Prior stress fracture Rapid increase in training intensity (speed) Rapid increase in training volume (distance) Female athlete triad (or tetrad) Coxa vara Leg-length discrepancy Training errors Hard running surfaces Insufficiency fracture risks Metabolic bone disease Chronic renal disease Endocrinopathy Smoking Infection Bone tumor at femoral neck Postradiation therapy
In these situations, the reparative capacity of the bone cannot overcome the destructive loads placed on it. Stress fractures are most commonly observed in the tibia (24%), tarsal navicular (18%), metatarsal (16%), fibula (16%), and femoral neck (5%).2,3 Endurance athletes may be particularly at risk, especially females, military recruits, runners, and triathletes.4,5 Microtrauma to bone occurs with physical activity that induces strain.6 In normal bone, the microdamage is repaired and osseous homeostasis maintained. An increase in the number or size of the microcracks may lead to eventual fatigue failure of the bone—stress fracture. This pathology represents a spectrum of injury from stress response to incomplete fracture to complete nondisplaced fracture line to displaced fracture.6 Fracture healing is multifactorial. However, the location may be the most important predictor of delayed union, nonunion, and refracture. Fractures in locations prone to these 3 outcomes are categorized as “high risk.”7 These include anterior tibial cortex, medial malleolus, talar neck, dorsal tarsal navicular, proximal fifth metatarsal metaphysis, tension side patella, and tension side of the femoral neck. The risk of
A
avascular necrosis following treatment of displaced femoral neck fractures in adults may be as high as 45%.8,9
Proximal Femoral Anatomy The hip is a synovial ball-and-socket joint, comprising the spherical femoral head and acetabulum. Recent appreciation of differing degrees of severity of nonarthritic hip pathology related to femoroacetabular impingement and dysplasia has significantly improved the understanding of “normal hip anatomy.” The femoral neck is composed of both compact cortical and cancellous trabecular bone. The proximal femur can be radiographically analyzed using the appearance of the trabecular group (compressive, tensile, and greater trochanteric) and type (primary and secondary) (Fig. 1A).10 During upright gait, there exists a coronal plane rotatory equilibrium between vectors of body weight and abductor tension to maintain a level pelvis (Fig. 1B). The resultant moment is responsible for designation of “compressive” and “tensile” sides of the femoral neck. Deviation away from normal femoral neck anatomy may place excessive stress on both the hip joint and the femoral neck. The normal neck-shaft angle (angle of inclination and caput-collum-diaphyseal) angle is approximately 1251.11 In patients with coxa vara (decreased neck-shaft angle), the tip of the greater trochanter is above the center of the femoral head, the abductor muscle length is shortened, and there is an increase in abductor lever arm. Thus, the latter requires less abductor muscle force to maintain a level pelvis, beneficial for those with abductor weakness. However, the increased abductor lever arm also increases the bending moment across the tension side of the femoral neck, placing it at risk of femoral neck fracture. In patients with coxa valga (increased neck-shaft angle), the tip of the greater trochanter is below the center of the femoral head, the abductor muscle length is increased, and there is a decrease in abductor lever arm. Thus, the latter requires greater abductor muscle force to maintain a level pelvis. The decrease in abductor lever arm decreases the bending moment across the femoral neck.
B
Figure 1 (A) Anteroposterior (AP) radiograph of an 18-year-old woman with outlined illustration of trabeculae of proximal femur. GTT, greater trochanteric trabeculae; PCT, primary compressive trabeculae; PTT, primary tensile trabeculae; SCT, secondary compressive trabeculae; STT, secondary tensile trabeculae; WT, Ward's triangle. (B) Anteroposterior (AP) radiograph of an 18-year-old woman with hip center of rotation marked. The product of the force of body weight and its associated moment arm equals the product of the abductor muscle force and its associated moment arm. According to Newton's third law of motion, for every action (abductor muscle tension and body weight), there is an equal and opposite reaction (joint reaction force).
Femoral neck stress fractures Femoral version is defined as the angular difference between the central axis of the femoral neck and the transepicondylar axis at the knee. Normal femoral version is approximately 151.12 Increased (femoral anteversion) or decreased (femoral retroversion) version requires increased internal or external rotation, respectively, to maintain femoral head stability within the acetabulum. Increased femoral anteversion effectively shortens the coronal plane abductor lever arm by placing the greater trochanter posteriorly and closer to the hip center. Increased femoral retroversion may effectively increase the abductor lever arm, with a potential increased bending moment across the femoral neck.
243 Table 2 Differential Diagnosis of Activity-Related Hip Pain Femoroacetabular impingement Cam Pincer Extra-articular impingement Iliopsoas impingement Subspine impingement Trochanteric-pelvic impingement Ischiofemoral impingement Dysplasia Abductor fatigue Labral tear
Patient Evaluation Subjective Patients with femoral neck stress fractures typically present to the clinician with an insidious onset of pain deep anteriorly in the groin or hip or anteromedial thigh. The pain is activity related, worse with weight-bearing activities that load the extremity and better with rest. A “C” sign or “between the fingers” sign may be exhibited, indicative of an intra-articular problem.13 The femoral neck is an intra-articular structure. Thus, the differential diagnosis of deep anterior groin or hip pain involves several other sources within the hip joint (Table 2). An important component of the history should inquire about the patient’s training regimen (frequency, duration, intensity, events [eg, marathon], changes in form, and changes in footwear). In runners, pain typically begins with onset of weight bearing early in the run. Pain may progressively increase and does not remit until the run ends. In some athletes, the desire to train or perform may supersede the pain. This may lead to disastrous consequences if a femoral neck stress fracture completes itself and displaces. This situation may be life changing, as the surgical treatment and potential complications of a displaced femoral neck fracture are dramatically different from those of an incomplete nondisplaced stress fracture. For females, the female athlete triad (amenorrhea, disordered eating or nutrition, and osteoporosis) or tetrad (cardiovascular endothelial dysfunction) symptoms must be assessed.14 Disordered eating leads to a negative caloric (and protein) balance, due to increased physical activity (caloric deficit) combined with undereating (or poor eating and further deficit). Amenorrhea is the result of a hypoestrogenism. Estrogen is a pro-osteoblastic hormone. Thus, low estrogen results in poor bone repair when microdamage occurs during osseous strain from training. A combination of endocrine and metabolic factors may lead to endothelial dysfunction, a potential precursor to cardiovascular disease.
Objective—Physical Examination Physical examination of an individual with activity-related hip pain should be systematic, beginning with inspection, followed by palpation, motion, strength, and special testing. Before inspection, observation of the patient entering the room or
Peritrochanteric pain syndrome Greater trochanteric bursitis Snapping iliotibial band (coxa saltans externa) Abductor tendon pathology Iliopsoas strain Adductor tendinopathy Athletic pubalgia Proximal hamstring syndrome Stress fracture Femoral neck Pubic ramus Sacrum Inflammatory arthropathy Avascular necrosis Referred pain Lumbosacral spine Gastrointestinal tract Gynecologic or urologic
walking down the office hall may reveal an antalgic gait. Inspection typically is unremarkable, with a lack of any cutaneous abnormalities, muscle atrophy, or lumbopelvic or extremity deformity. Palpation should assess all bony and soft tissue structures amenable to palpation. The hip joint itself is deep, even in thin patients, making palpation of the femoral neck impossible. Specific areas to be assessed during palpation should include greater trochanteric facets, abductor tendons, common adductor tendon, pubis, pubic symphysis, inguinal ligament, iliac crest, ischial tuberosity, proximal hamstring, sacroiliac joint, and lumbosacral spine. Hip range of motion, including comparison to the uninjured side for symmetry, should assess flexion, extension, abduction, adduction, and internal and external rotations. These may be measured seated, supine, lateral, or prone. Muscle strength testing of the paraspinal muscles and all lower extremity myotomes is also performed. Special testing may include single-leg stance (pain with weight bearing or a Trendelenburg sign), single-leg squat, single-leg hop, axial load, axial distraction, logroll, external rotation recoil test, impingement testing (anterior, subspine, lateral, posterior, and trochanteric-pelvic), McCarthy test, iliopsoas testing (Ludloff, iliopsoas test, and iliopsoas snap),
J.D. Harris and J. Chahal
244
fracture remains, advanced imaging may be obtained, such as magnetic resonance imaging (MRI).
Objective—Plain Radiographs—Stress Fracture Classification
Figure 2 Anteroposterior (AP) radiograph of the hip of a 16-year-old woman with healed compression-side left femoral neck fracture. The white arrow indicates the sclerotic area of fracture union.
Ober test, and iliotibial band snap. Patients with femoral neck stress fractures frequently reveal pain with single-leg stance, squat, and hop, axial load, logroll, and anterior impingement testing. However, it cannot be overemphasized sufficiently that if a significant concern for femoral neck stress fracture exists, then stressful physical examination of the hip should be avoided to obviate fracture displacement.
Objective—Plain Radiographs Plain radiographs should be obtained for patients with activityrelated hip pain in the setting of concern for femoral neck stress fracture. At a minimum, standing anteroposterior (AP) pelvis and at least one lateral hip (frog-leg, Dunn 451, Dunn 901, cross-table, Lauenstein, and false profile) radiograph should be obtained. Radiographic analysis should assess the femoral neck for fracture, fracture healing (Fig. 2), femoroacetabular impingement, dysplasia, arthritis, and bony or soft tissue lesions (Table 3). Further, the presence of coxa vara has been associated with femoral neck stress fracture.15 If plain radiographs do not reveal evidence of fracture, yet concern for stress
To classify femoral neck stress fractures, 4 different classifications exist. Of these, 3 systems may exclusively use plain radiographs. The clinically most relevant, easily applied, generalizable one with the highest interobserver and intraobserver reliability is the system created by Kaeding and Miller.6 This system uses 5 grades, 1 through 5. Grade 1 is a painless asymptomatic stress response visible on imaging. Grade 2 also illustrates a stress response without a fracture line. However, Grade 2 injuries are symptomatic. Grade 3 and Grade 4 injuries both have a visible fracture line. Grade 3 injuries are nondisplaced and Grade 4 are displaced. Grade 5 injuries are nonunions. The Devas classification divided fractures into compression- and tension sides.16 The Blickenstaff and Morris classification has 3 types: Type 1 (callus and without fracture line), Type 2 (nondisplaced fracture line), and Type 3 (displaced fracture).17 The Fullerton and Snowdy classification also has 3 types: tension side, nondisplaced; compression side, nondisplaced; and displaced.3
Objective—MRI If plain radiographs do not reveal stress fracture of the femoral neck, then the gold standard imaging test of choice is MRI, with both sensitivity and specificity of up to 100%.18 Technetium-99m-labeled methylene diphosphonate bone scan (Triple Phase Bone Scintigraphy) is a sensitive examination to detect femoral neck stress fracture, but has poor specificity.19 Further, anatomical delineation of fracture location is poor with bone scan. Computed tomography scans are
Table 3 Plain Radiographic Variables Analyzed AP Pelvis Femoral neck fracture Compression side, incomplete, nondisplaced Tension side, incomplete, nondisplaced Complete, nondisplaced Complete, displaced, o50% width of cortex Complete, displaced, 450% width of cortex Tonnis grade Neck-shaft angle (1) Prominent ischial spine sign Posterior wall sign Crossover sign Lateral center edge angle (1) Tonnis angle (1) Coxa profunda Protrusio acetabulae Greater trochanter tip position relative to femoral head center Superolateral acetabular rim fracture Joint space at medial, middle, and lateral sourcil (mm) Alpha angle (1) Femoral head extrusion index
False Profile Anterior center edge angle (1) Anterior inferior iliac spine type Dunn 451 (or other lateral view of choice) Alpha angle (1) Head-neck offset (mm) Maximal head diameter (mm) Head-neck offset ratio
Femoral neck stress fractures
A
245
B
Figure 3 (A) Coronal T2-weighted MRI demonstrating compression-side right femoral neck stress fracture without evidence of cortical disruption. (B) Coronal T2-weighted MRI demonstrating compression-side right femoral neck stress fracture with evidence of medial cortical disruption.
associated with significant radiation exposure and low sensitivity of detecting stress fracture, but do have high specificity.19 MRI may be obtained to evaluate both intra- and extraarticular bony and soft-tissue structures in and around the hip joint. Axial, sagittal, and coronal series should be obtained. If radial or axial oblique imaging is available at the magnetic resonance facility, they may be helpful for evaluation of the acetabular labrum and femoral head-neck junction. T2weighted, short-tau inversion recovery, or any fluid-sensitive, fat-suppressed series are most helpful to visualize the spectrum of stress fractures, including bone marrow edema and incomplete or complete fracture with or without cortical disruption (Fig. 3). MRI may also illustrate labral injury, avascular necrosis, bony or soft tissue benign or malignant lesions, effusion, articular cartilage injury, osteoarthritis, and synovial chondromatosis, among other less common causes of hip pain. Intra-articular contrast is unnecessary in the evaluation of femoral neck stress fracture.
Management Nonsurgical Treatment The indication for nonsurgical treatment of femoral neck stress fracture includes compression-sided incomplete fracture. Nonsurgical treatment includes non–weight-bearing with crutch-assisted or walker gait-aide-assisted ambulation. During the protection period, which is a minimum of 6 weeks, a full evaluation for stress fracture risks (Table 1) is undertaken and a treatment program initiated. This may include calcium and Vitamin D, among other nutritional supplementation (Table 4). Nutrition, endocrinology, and psychology or psychiatry consultation are warranted, especially in the setting of the female athlete triad. Core strengthening, non weight bearing hip motion, and non weight bearing hip and pelvis strengthening may continue with nonsurgical treatment. After a 6-week period of protected weight bearing, the presence of pain with axial load (weight-bearing) is an indication for obtaining repeat imaging. Serial imaging with plain radiographs may reveal cortical sclerosis, periosteal
thickening, and disappearance of a visible fracture line as the fracture heals. Fracture nonunion may illustrate a persistent fracture line with sclerotic fracture ends. Following the protection period, if plain radiographs do not reveal any objective evidence of fracture union or non-union, advanced imaging with MRI is indicated. This permits magnetic resonance comparison of the injury severity. Surgical fixation may be indicated if the MRI reveals worsening or persistence of the stress fracture. Fracture displacement on any imaging modality is an indication to abandon nonsurgical treatment and anatomically reduce and fix the fracture.
Surgical Treatment The indications for surgical treatment of femoral neck stress fractures include (1) complete fracture with or without displacement, (2) tension-sided incomplete fractures, and (3) compression-sided incomplete fractures that have failed nonsurgical treatment for a minimum of 6 weeks. Surgical treatment for non-displaced fractures includes percutaneous screw fixation with 6.5- or 7.3- mm screws (Fig. 4). Partially threaded screw design with or without cannulation is the standard of care. Standard preoperative evaluation and clearance is recommend in the elective setting for nondisplaced stress fractures. However, increasing degrees of fracture displacement warrant urgent evaluation, optimization, and preparation for surgery. Table 4 Metabolic Bone Disease Laboratory Evaluation For Femoral Neck Stress Fracture; Gonadotropin-Releasing Hormone (GnRH); Follicle-Stimulating Hormone (FSH); Luteinizing Hormone (LH) Comprehensive metabolic panel (especially calcium, magnesium, and phosphorus) Albumin Alkaline phosphatase Vitamin D Endocrine and sex hormones Thyroid, parathyroid Estrogen, progesterone GnRH, FSH, LH
J.D. Harris and J. Chahal
246
A
B
C
Figure 4 (A) Anteroposterior (AP) radiograph of a 26-year-old woman following percutaneous screw fixation of right incomplete compression-side femoral neck stress fracture that failed 8 weeks of nonsurgical treatment. (B) False-profile radiograph of the 26-year-old woman following percutaneous screw fixation of right incomplete compression-side femoral neck stress fracture that failed 8 weeks of nonsurgical treatment. (C) Dunn 901 radiograph of the 26-year-old woman following percutaneous screw fixation of right incomplete compression-side femoral neck stress fracture that failed 8 weeks of nonsurgical treatment.
General anesthesia is recommended, with a dose of firstgeneration cephalosporin intravenous antibiotic prophylaxis given within 30 minutes of skin incision. Supine positioning on a radiolucent operating room table permits large C-arm fluoroscopy evaluation of screw location. Before sterile preparation and draping, the surgeon and team must assure that AP and lateral views are obtainable with the positioning on the bed. Typically, the lateral views are more challenging owing to the base of the bed and any metallic rod support for the bed that could obscure evaluation of the femoral head and neck. A standard radiolucent operating room bed, fracture table, or hip arthroscopy bed may be used, as long as a well-padded perineal post is used. After general anesthesia induction, the surgeon must be cognizant that even a gentle examination under anesthesia or vigorous limb manipulation during positioning may displace the fracture. The nonoperative extremity may be placed in a good leg holder, flexed, and abducted, to permit the C-arm unit easy access to the operative hip joint. A sequential compression device may be used on the nonoperative leg. Fluoroscopy is used to localize skin incision placement along the lateral proximal thigh; 2 different skin incision techniques may be used. The authors prefer a single vertical incision over the iliotibial band at the level of the lesser trochanter. The incision is usually no larger than 3-5 cm. This permits an incision in the iliotibial band and tensor fascia lata in line with skin incision and placement of all 3 screws via this single incision. An alternative is a o1 cm incision “poke hole” for placement of each screw. Skin and iliotibial band mobility is less forgiving with this approach given the size of the incisions; 3-threaded guide pins (usually 2.8-mm diameter) are placed in an inverted equilateral triangle configuration. Pin position order is as follows: (1) inferior (on AP) and central (on lateral), (2) superior (on AP) and anterior (on lateral), and (3) superior (on AP) and posterior (on lateral). A multiple parallel wire guide may be used to more efficiently achieve the inverted triangle position. A freehand technique without a guide may also be used (authors’ preference). The guide pins must remain in the bone and not breach the articular surface of the femoral head. The lateral cortex is opened with a 5.0-mm cannulated drill bit over the guide pin. As the screws are self-drilling and
self-tapping, usually only the lateral cortex needs to be opened. Only in the setting of very hard dense bone is further drilling toward the head with the 5.0-mm drill required. The surgeon may need to fluoroscopically assure that the threaded guide pins do not advance across the subchondral plate into the joint with drilling and screw placement. The inferior screw is placed first, along the inferior margin of the femoral neck, in the center of the neck on the lateral view, subchondral, without femoral head intra-articular penetration. A washer may be used to gain compression on the lateral wall of the proximal femur. The screw should begin just above the lesser trochanter to avoid stress riser effect at screw entry location. Stainless steel (316L) or titanium alloy screws are available. The second and third screws should be placed more superior in the neck, near the superior cortex on the AP view, with one screw anterior and one screw posterior. After the first partially threaded screw is placed and compressed, the second and third screws may be either fully or partially threaded. The thread length (usually 16 or 32 mm) for the initial screw should pass (go proximal to) the location of the fracture to achieve compression. Displaced fractures require anatomical reduction and internal fixation. Thus, if a closed reduction is unable to be achieved under anesthesia, then an anterior Smith-Petersen approach to the hip is necessary to anatomically reduce and fix the fracture. The superficial internervous interval is between sartorius (femoral nerve) and tensor fascia lata (superior gluteal nerve) muscles. The surgeon must appreciate and preserve the anatomy of the lateral femoral cutaneous nerve as it courses under the inguinal ligament, travels distally and laterally along the superficial aspect of the sartorius, and subsequently branches into anterior (femoral) and posterior (gluteal) divisions. The deep internervous interval is between rectus femoris (femoral nerve) and gluteus medius (superior gluteal nerve). Medial retraction of the iliopsoas and rectus femoris direct (anterior inferior iliac spine superior facet) and indirect (superolateral capsular margin) heads and lateral retraction of the gluteus medius permit exposure of the capsule. The capsule may be distended with hemarthrosis in the presence of fracture displacement. Capsulotomy is required
Femoral neck stress fractures for visualization of the femoral neck. This may include simple longitudinal “T-” or “Z-”shaped capsulotomies for exposure. Limb rotation and translation may be used to reduce the fracture with visual inspection for verification of anatomical reduction. The surgeon must avoid the temptation to place retractors posterolaterally over the neck to avoid iatrogenic disruption of the lateral ascending branches of the medial femoral circumflex artery blood supply to the femoral head. Once the fracture is reduced anatomically, the same procedure for percutaneous screw fixation is performed via a second incision laterally as done with nondisplaced stress fractures discussed previously. Postoperatively, following percutaneous screw fixation of a nondisplaced stress fracture, patients may begin weight bearing as tolerated on the affected lower extremity. Normal gait should be achieved within the first month following surgery. Patients should be cautioned against running or dynamic explosive loading or jumping until 6-8 weeks following surgery, provided the patient is pain free with normal gait. Serial plain radiographs may be used to visualize fracture healing. Following open reduction and internal fixation of displaced fractures, patients need to protect the reduction and fixation via a minimum of 6-8 weeks of non weight bearing with 25% interval increases per week to full weight bearing by approximately 10-12 weeks.
Conclusions Stress fractures are common overuse injuries in the lower extremities. Femoral neck stress fractures account for less than 5% of all stress fractures. A thorough history, physical examination, and radiographic evaluation can appropriately diagnose and classify these injuries. Generally, compressionsided fractures are successfully treated nonsurgically with non weight bearing crutch-assisted ambulation. Tensionsided stress fractures and all complete displaced fractures are treated surgically. Fracture displacement requires anatomical reduction and fixation. Screws are the standard of care for fracture fixation. Complications include displacement, nonunion, delayed union, varus malunion, and avascular necrosis.
247
References 1. Brukner P, Bradshaw C, Khan KM, et al: Stress fractures: A review of 180 cases. Clin J Sport Med 6(2):85-89, 1996 2. Matheson GO, Clement DB, McKenzie DC, et al: Stress fractures in athletes. A study of 320 cases. Am J Sports Med 15(1):46-58, 1987 3. Fullerton Jr LR: Femoral neck stress fractures. Sports Med 9(3):192-197, 1990 4. Pihlajamaki HK, Ruohola JP, Weckstrom M, et al: Long-term outcome of undisplaced fatigue fractures of the femoral neck in young male adults. J Bone Joint Surg Br 88(12):1574-1579, 2006 5. Pihlajamaki HK, Ruohola JP, Kiuru MJ, et al: Displaced femoral neck fatigue fractures in military recruits. J Bone Joint Surg Am 88(9): 1989-1997, 2006 6. Kaeding CC, Miller T: The comprehensive description of stress fractures: A new classification system. J Bone Joint Surg Am 95(13):1214-1220, 2013 7. Boden BP, Osbahr DC: High-risk stress fractures: Evaluation and treatment. J Am Acad Orthop Surg 8(6):344-353, 2000 8. Dedrick DK, Mackenzie JR, Burney RE: Complications of femoral neck fracture in young adults. J Trauma 26(10):932-937, 1986 9. Bachiller FG, Caballer AP, Portal LF: Avascular necrosis of the femoral head after femoral neck fracture. Clin Orthop Relat Res 399:87-109, 2002 10. Singh M, Nagrath AR, Maini PS: Changes in trabecular pattern of the upper end of the femur as an index of osteoporosis. J Bone Joint Surg Am 52(3):457-467, 1970 11. Reikeras O, et al: Femoral neck angles: A specimen study with special regard to bilateral differences. Acta Orthop Scand 53(5):775-779, 1982 12. Fabricant D, Fields KG, Taylor SA, et al: The effect of femoral and acetabular version on clinical outcomes after arthroscopic femoroacetabular impingement surgery. J Bone Joint Surg Am 97(7):537-543, 2015 13. Harris JD, Gerrie BJ, Lintner DM, et al: Microinstability of the hip and the splits x-ray. Orthopedics 2015 14. Temme KE, Hoch AZ: Recognition and rehabilitation of the female athlete triad/tetrad: A multidisciplinary approach. Curr Sports Med Rep 12 (3):190-199, 2013 15. Carpintero P, Leon F, Zafra M, et al: Stress fractures of the femoral neck and coxa vara. Arch Orthop Trauma Surg 123(6):273-277, 2003 16. Devas MB: Stress fractures of the femoral neck. J Bone Joint Surg Br 47 (4):728-738, 1965 17. Blickenstaff LD, Morris JM: Fatigue fracture of the femoral neck. J Bone Joint Surg Am 48(6):1031-1047, 1966 18. Kiuru MJ, Pihlajamaki HK, Hietanen HJ, et al: MR imaging, bone scintigraphy, and radiography in bone stress injuries of the pelvis and the lower extremity. Acta Radiol 43(2):207-212, 2002 19. Gaeta M, Minutoli F, Scribano E, et al: CT and MR imaging findings in athletes with early tibial stress injuries: Comparison with bone scintigraphy findings and emphasis on cortical abnormalities. Radiology 235(2):553-561, 2005
