Femoral Neck Stress Fracture Research Articles

Bilateral neck of femur stress fracture secondary to osteopetrosis treated with dynamic hip screw

Osteopetrosis, a rare hereditary bone disorder, is characterized by increased bone density due to defective osteoclast-mediated bone resorption. This condition often leads to skeletal fragility, resulting in recurrent fractures despite increased bone mass. Among these, stress fractures of the femoral neck pose a unique challenge where conventional management may not be optimal. Valgus osteotomy offers a viable surgical intervention to realign the mechanical axis, thereby reducing stress on the femoral neck and facilitating healing. This paper reviews the pathophysiology of osteopetrosis, its impact on fracture healing, and the role of valgus osteotomy in managing femoral neck stress fractures in osteopetrotic patients.

Bilateral Femoral Neck Stress Fractures Due to Opioid Abuse-Induced Osteoporosis: Two Case Reports and Review of Literature

Bilateral Femoral Neck Stress Fractures Due to Opioid Abuse-Induced Osteoporosis: Two Case Reports and Review of Literature

Tenofovir Induced Bilateral Femoral Neck Stress Fracture

Case: A 47 year old male, came with history of bilateral hip pain ,insidious in onset gradually progressive, with difficulty in walking unassisted since 2 years. No history of fall/ trauma. Patient is known case of retroviral disease and on ART (TLE regimen ) since 2 years. Relevant radiographs were done and was diagnosed with bilateral neck of femur stress fracture (Tenofovir induced) associated with hypophosphatemia. ART regimen was changed to (Abacavir ,Lamivudine , Dolutegravir) . Patient on regular follow up every 2 months with serial radiographs. . On 6 months follow up patient is symptomatically improved with healing bilateral neck of femur stress fracture.

Fratura de Stress do Colo do Fémur em Atleta de CrossFit

Femoral neck stress fractures are infrequent. They are more prevalent among athletes, with women being at a higher risk. A 29-year-old female amateur CrossFit athlete complained of right-sided groin pain after a high intensity training. An X-ray showed no signs of acute lesions, but further CT scan and MRI revealed a compression-type femoral neck stress fracture. The patient underwent conservative treatment, restricting full weight-bearing during six weeks. She became asymptomatic at four months and returned to sports at six months. Follow-up imaging confirmed fracture union. This diagnosis is crucial when assessing athletes, including amateurs, as early recognition is vital due to high complication and morbidity rates.

261 Bilateral Femoral Neck Stress Fractures in an Active Adolescent Female: A Case Report

Abstract Bilateral femoral neck stress fractures are uncommon injuries in adolescents. We present such a case in a 15-year-old athletic female with no preceding trauma or underlying metabolic bone abnormality. The patient presented to Accident and Emergency with a three-week history of left buttock and lateral thigh pain and one-week history of right lateral thigh pain. The pain developed during physical activity and was relieved upon rest. Activities included running, dancing, and attendance at a six-week cadet marching course. Simple analgesia did not alleviate the pain. History revealed low caloric intake and previous secondary amenorrhea. The patient was previously managed by the General Practitioner and physiotherapist for suspected atypical sciatica. Physical examination showed a minimally antalgic gait and pain on palpation of the left groin. Both hips had full range of motion. Bone profile was normal. Radiographic films were initially interpreted as normal, however, formal reporting revealed sclerotic appearances to both femoral necks and a subtle break in the left femoral neck cortex. MRI confirmed the diagnosis of a complete displaced left femoral neck fracture and incomplete right inferomedial femoral neck fracture. Trace bilateral hip joint effusions were noted. The patient underwent bilateral fixation with cannulated screws. One-month post-operative, she engaged in walking and swimming without pain. Radiographic appearances were satisfactory. Early radiographic changes associated with stress fractures are subtle. This case highlights the importance of prompt formal radiological reporting and the early use of MRI as a diagnostic tool, particularly in patients with risk factors.

Osteoid osteomas of the hip: a well-recognized entity with a proclivity for misdiagnosis

ObjectivesThe diagnosis of osteoid osteomas (OO) about the hip can be challenging as presenting symptoms can mimic other, more common, periarticular pathologies. Our aims were to identify the most common misdiagnoses and treatments, mean delay in diagnosis, characteristic imaging features and provide tips for avoiding diagnostic imaging pitfalls for patients with OO of the hip.MethodsWe identified 33 patients (34 tumors) with OO about the hip who were referred for radiofrequency ablation between 1998 and 2020. Imaging studies reviewed included radiographs (n = 29), CT (n = 34), and MRI (n = 26).ResultsThe most common initial diagnoses were femoral neck stress fracture (n = 8), femoroacetabular impingement (FAI) (n = 7), and malignant tumor or infection (n = 4). The mean time from symptom onset to diagnosis of OO was 15 months (range, 0.4–84). The mean time from initial incorrect diagnosis to OO diagnosis was 9 months (range, 0–46).ConclusionsThe diagnosis of OO of the hip is challenging, with up to 70% of cases initially misdiagnosed as a femoral neck stress fracture, FAI, bone tumor, or other joint pathology in our series. Consideration of OO in the differential diagnosis of hip pain in adolescent patients and awareness of the characteristic imaging findings are critical for making an accurate diagnosis.Key Points• The diagnosis of osteoid osteoma of the hip can be challenging, as demonstrated by long delays in time to initial diagnosis and high rates of misdiagnoses which can lead to inappropriate interventions.• Familiarity with the spectrum of imaging features of OO, especially on MRI, is imperative given the increase in the utilization of this modality for the evaluation of young patients with hip pain and FAI.• Consideration of OO in the differential diagnosis of hip pain in adolescent patients and awareness of the characteristic imaging findings, including bone marrow edema and the utility of CT, are critical for making a timely and accurate diagnosis.

Consensus and Equipose in the Management of Military Trainee Femoral Neck Stress Fractures: A Survey of Military Surgeons.

Femoral neck stress fractures (FNSFs) are a unique injury pattern not commonly treated in the civilian trauma population; however, it is particularly high with military trainees engaged in basic combat training. To date, no study has surveyed a population of military orthopedic surgeons on treatment preferences for military service members (SMs) with FNSF. We aim to evaluate the extent of clinical equipoise that exists in the management of these injuries, hypothesizing that there would be consensus in the factors dictating surgical and non-surgical intervention for FNSF. A 27-question survey was created and sent to U.S. military orthopedic surgeon members of the Society of Military Orthopaedic Surgeons. The survey was designed in order to gather the experience among surgeons in treating FNSF and identifying variables that play a role in the treatment algorithm for these patients. In addition, seven detailed, clinical vignettes were presented to further inquire on surgeon treatment preferences. Binomial distribution analysis was used to evaluate for common trends within the surgeon's treatment preferences. Seventy orthopedic surgeons completed the survey, the majority of whom were on active duty status in the U.S. Military (82.86%) and having under 5 years of experience (61.43%). Majority of surgeons elected for a multiple screw construct (92.86%), however the orientation of the multiple screws was dependent on whether the fracture was open or closed. Management for compression-sided FNSF involving ≥50% of the femoral neck width, tension-sided FNSF, and stress fractures demonstrating fracture line progression had consensus for operative management. Respondents agreed upon prophylactic fixation of the contralateral hip if the following factors were involved: Complete fracture (98.57%), compression-sided fracture line >75% (88.57%), compression-sided fracture line >50-75% with hip effusion (88.57%), contralateral tension-sided fracture (87.14%), and compression-sided fracture line >50-75% (84.29%). An FNSF < 50% on the contralateral femoral neck or a hip effusion was indeterminate in surgeons indicating need for prophylactic fixation. Majority of surgeons (77.1%) utilized restricted toe-touch weight-bearing for postoperative mobility restrictions. Consensus exists for surgical and non-surgical management of FNSF by U.S. military orthopedic surgeons, despite the preponderance of surgeons reporting a low annual volume of FNSF cases treated. However, there are certain aspects in the operative and non-operative management of FNSF that are unanimously adhered to. Specifically, our results demonstrate that there is no clear indication on the management of FNSF when an associated hip effusion is involved. Additionally, the indications for surgically treating contralateral FNSF are unclear. IV.

Stress fracture of ipsilateral femoral neck after total knee replacement: 2 cases report

The main complications after total knee replacement were pain, infection, thrombosis and nerve injury, but few patients had ipsilateral femoral neck fractures, which might be related to changes of the biomechanical axis of the knee joint, increasing activity level, osteoporosis, and high BMI, following TKR.

Bilateral Stress Fracture of the Femoral Neck: A Case Report

Bilateral femoral neck stress fracture is rarely seen. Two radiologic types of femoral neck stress fracture, the transverse and the compression, have been described. This differentiation bears importance in the choice of treatment. In this report, we presented a case of bilateral femoral neck stress fracture with a short review of contemporary literature.

Correlation between Abnormal Gait Pattern With Femoral Neck Stress Fracture In Athletes: A Systematic Review

Backgrounds: Stress fractures are common overuse injuries in the lower extremities. Repetitive episodes of high-intensity or extended-duration axial load to the leg place 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). 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, nonunion, and avascular necrosis if displaced. Fractures in locations prone to these 3 outcomes are categorized as “high risk.” 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 avascular necrosis following treatment of displaced femoral neck fractures in adults may be as high as 45%. 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 paper describes side effects abnormal gait pattern to femoral neck stress fractures in athlete. Methods: Our trial was an international, expertise-based, randomized, controlled trial. Details of the trial objectives and design have been published previously. Additional information about the eligibility criteria, interventions, follow-up, outcome definitions, and statistical analysis. To identify studies pertaining to the clinical results about Correlation between Abnormal Running Gait Pattern and Femoral Neck Stress Fracture, we reviewed the Cochrane, Pubmed, Embase databases for relevant articles published up to July 2022. We also reviewed the references of all identified articles to identify additional studies. Search terms were as follows: femoral neck stress fracture, femoral fracture, running gait. Following the PICOS (Participants, Interventions, Comparisons, Outcomes and Study design) principle, the key search terms included (P) patients were runner with FNSFs; (I) patients were running as a recreational sport, and or professional athlete; (C/O) the outcomes including sign and symptoms, femoral neck stress fracture, length of rehabilitation, time to get back in early performance in sport; (S) RTC, cohort study, or case control study. Results: A total of 13 RCTs, meta- analysis and systematic review correlation abnormal running gait with femoral neck stress fractures. Discussions: There are correlations between abnormal running gait with femoral neck fractures, because abnormal running gait with high intense could make bone stress injury. However, bone stress injury at neck femoral is one of many factors that commonly happen become a femoral neck stress fractures. Conclusions: Abnormal running gait combining with high intense training are etiology of bone stress injuries in athletes. Bone stress injuries in femoral neck could possibly become femoral neck stress fractures.

PSAT222 Muscle Weakness, Bone Pain, and Stress Fractures: When a Fracture is NOT JUST a Fracture: A Case Report

Abstract Case A previously healthy 46-year-old male presented to orthopedic clinic with bilateral hip pain, and progressive weakness without history of trauma requiring cane for ambulation. X-ray and MRI evaluation revealed stress fractures of left subtrochanteric femur and right basicervical femoral neck, both requiring surgery. In hospital blood work revealed elevated total alkaline phosphatase 167 units/L, mild hypocalcemia 8.5 mg/dL, and low 25-hydroxy Vitamin D 18 ng/mL. The patient was started on calcium/vitamin D supplements upon discharge. Initial endocrinology outpatient work-up revealed low phosphorus level of 2.1 mg/dl and low 1, 25 OH vitamin D of 5.9 pg/ml (19.9–79.3). Bone mineral density revealed normal spine bone density, and 1/3 radius osteopenia (T score -1.1). Physical exam revealed profound proximal weakness with inability to rise independently from sitting position. Follow-up of low phosphorous level demonstrated an elevated FGF-23 level of 186 RU/mL (normal &amp;lt; 180) and elevated fractional excretion of phosphorus 16% (expect &amp;lt; 5% with hypophosphatemia), indicating inappropriate renal phosphate wasting. The patient was started on Calcitriol and phosphorus. Before above evaluation was completed the patient had an ED visit with complaint of small mass just below left knee associated with mild pain and warmth. Ultrasound and MRI showed a complex cyst which was aspirated and showed cystic appearing mass suggestive of hematoma. This was treated with antibiotic course. Due to suspicion of tumor-induced osteomalacia, octreotide scan (Indium-111 pentetreotide) performed showed focal increased activity in the medial left knee. MRI showed a 26 mm cystic lesion within the subcutaneous tissue along the inferomedial aspect of the left knee, which correlated with the site of radiotracer uptake on the octreotide scan. The patient underwent left knee soft tissue tumor resection, and pathology demonstrated phosphaturic mesenchymal tumor. Follow-up several weeks postoperatively showed normalization of phosphorus and FGF-23 level. The patient's mobility and weakness improved significantly within a few months. Discussion Tumor-induced osteomalacia is a rare paraneoplastic condition characterized by chronic hypophosphatemia secondary to excessive tumoral FGF 23 production. Typical presenting symptoms are profound muscle weakness, bone pain, and fractures. Diagnosis is often delayed for several years, as phosphorus levels are not included in a routine metabolic panel. Considering high morbidity of this condition including significant mobility limitation requiring use of assistive devices, healthcare provider vigilance is paramount as this condition is potentially curable if the offending tumor is detectable and amenable to surgical resection. This case illustrates the importance of consideration of an underlying metabolic bone disease in patients with unexplained atraumatic fractures and hypophosphatemia. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

The Subcapital Femoral Neck Stress Fracture: A Novel Subtype of Compression-sided Stress Fracture-A Report of Three Cases.

Femoral neck stress fractures (FNSFs) are increasingly common, particularly in military training. The usual mode of classifying these injuries is based on the involvement of the compression or tension side of the femoral neck; however, this may oversimplify and fail to address factors such as the orientation of the fracture line. We present a novel subtype of a compression-sided FNSF affecting the subcapital femoral neck and report the treatment outcomes in a military trainee population. A retrospective analysis of patients with a subcapital, compression-sided FNSF was identified from a single U.S. Army basic trainee installation. Radiographic evaluation as well as treatment outcomes associated with the ability to complete military training were reported. A total of three patients with a subcapital compression-sided FNSF were identified in a military trainee population, accounting for 10% of all FNSFs that developed over a 3-month period. Of these individuals, one was treated operatively while the other two were treated non-operatively. Overall, one patient was able to return to and successfully complete military training.

Relation of Vitamin D Level, BMI, and Location of Lower Extremity Stress Fractures in Military Trainees.

Military trainees are at an increased risk of stress fractures. Vitamin D availability is known to play an important role in both fracture prevention and healing. The purpose of this investigation was to assess 25-hydroxy vitamin D (25(OH)D) levels in soldiers with confirmed lower extremity stress fractures and assess the predictors of fracture location. Following Institutional Review Board approval, military trainees at a large training base presenting to the orthopedic clinic with a radiographically verified stress fracture were identified. Demographic data and 25(OH)D levels were collected. A descriptive analysis was performed in regard to patient age, body mass index (BMI), and 25(OH)D level. Interactions between variables were assessed using one-way analysis of variance for four fracture location groups (femoral neck, femoral shaft, tibial shaft, and foot and ankle). Bivariate correlations were examined between age, BMI, and vitamin D level. A total of 155 lower extremity stress fractures were identified in 144 males and 11 females over 30 months. The mean age was 22.7 ± 4.85years. The majority (60.7%) of fractures were located in the femoral neck. The average 25(OH)D level was 26.8 ± 8.37 ng/mL. Overall, 26% (N = 41) of enrolled patients had normal 25(OH)D levels, 48% (N = 74) had insufficient 25(OH)D levels, and 26% (N = 40) had deficient 25(OH)D levels. Patients with femoral neck fractures and tibial shaft fractures had significantly lower BMI than patients with foot and ankle fractures (23.3 vs. 27.7, P < .001 and 24.2 vs. 27.7, P = .003, respectively). Patients with foot and ankle fractures had significantly lower 25(OH)D levels than patients with femoral shaft fractures (21.1 vs. 30.1, P = .02). There were no significant findings regarding age and fracture location. Age correlated positively (but weakly) with BMI (0.338, P < .001). There was no correlation between age and vitamin D level or BMI and vitamin D level. Overall, 74% of patients in military training with lower extremity stress fractures had insufficient or deficient levels of 25(OH)D, highlighting a persistent area of concern in this population. Patients with femoral neck and tibial shaft stress fractures had significantly lower BMI than patients with foot and ankle stress fractures. This suggests that in stress fracture-prone patients, BMI may play a role in predicting fracture location.

Femoral neck stress fracture and medial tibial stress syndrome following high intensity interval training: A case report and review of literature

BACKGROUNDFemoral and tibial stress injuries are commonly found in long distance running athletes. Stress fractures have rarely been reported in athletes performing high intensity interval training (HIIT) exercise. The objective of this study was to report a case of a patient who presented with medial tibial stress syndrome and femoral neck stress fracture after performing HIIT exercises. CASE SUMMARYA 26 year old female presented with bilateral medial tibial pain. She had been performing HIIT exercise for 45 min, five times weekly, for a seven month period. Her tibial pain was gradual in onset, and was now severe and worse on exercise, despite six weeks of rest. Magnetic resonance imaging (MRI) revealed bilateral medial tibial stress syndrome. As she was taking norethisterone for birth control, a dual energy X-ray absorbitometry scan was performed which demonstrated normal bone mineral density of her lumbar spine and femoral neck. She was managed conservatively with analgesia and physiotherapy, but continued to exercise against medical advice. She presented again six months later with severe right hip pain. MRI of her right hip demonstrated an incomplete stress fracture of her subtrochanteric region. Her symptoms resolved with strict rest and physiotherapy. CONCLUSIONHIIT may cause stress injury of the tibia and femur in young individuals.

Femoral neck stress fracture in a middle aged female: A case report

Stress fractures of the femoral neck are uncommon and may go unnoticed at first. Stress fractures are most commonly seen in athletes as overuse injuries. A 49 year old house wife presenting with continuous right knee pain aggravated by physical activity was diagnosed as Fullerton and Snowdy type two neck of femur stress fracture and was treated conservatively. If a stress fracture is not treated, it might deteriorate. It can cause poor healing, and even require surgery. Timely management is the key.

Bilateral symmetrical stress fractures of femoral neck in HIV patient: case report and brief review of literature

Osseous changes in HIV positive patients receiving ART are three times greater than in normal individuals. These changes include osteopaenia/osteoporosis, stress fractures, fragility fractures and osteonecrosis. On an average, bone mineral density reduces by 2-6% in the first 2 years after commencement of antiretroviral therapy. High risk for stress fractures is observed in these patients. In present article, we report a case of bilateral femoral neck stress fractures in a known HIV patient.

CORR Insights®: Surgically Treated Femoral Neck Stress Fractures Are Likely to Result in Military Separation During Basic Combat Training.

1Norman M. Rich Professor and Chair, Department of Surgery, Uniformed Services University-Walter Reed, Bethesda, MD, USA B. K. Potter ✉, Norman M. Rich Professor and Chair, Uniformed Services University of Health Sciences, 4310 Jones Bridge Road, A3011-SUR, Bethesda, MD 20814, USA, Email: [email protected] This CORR Insights® is a commentary on the article “Surgically Treated Femoral Neck Stress Fractures Are Likely to Result in Military Separation During Basic Combat Training” by Shaw and colleagues available at: DOI: 10.1097/CORR.0000000000002187. The author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writer, and do not reflect the opinion or policy of CORR® or The Association of Bone and Joint Surgeons®.

Surgically Treated Femoral Neck Stress Fractures Are Likely to Result in Military Separation During Basic Combat Training.

Femoral neck stress fractures are a common condition affecting military service members, most noticeably during basic combat training. Previous studies have investigated the risk factors for femoral neck stress fracture development in basic trainees and outcomes associated with treatment; however, few studies have focused on operatively treated femoral neck stress fracture in the military trainee. Doing so would be important not only for the military, but also providers caring for athletes, such as distance runners, who have a heightened risk for femoral neck stress fracture development. (1) What proportion of US Army trainees completing basic combat training at Fort Jackson, SC, USA, who undergo surgery for femoral neck stress fracture during basic training subsequently leave military service because of the injury? (2) What factors are related to the patient or the fracture are associated with a higher likelihood of military separation? (3) What factors on the initial MRI are associated with progression of the stress fracture extent? A retrospective study of a longitudinally maintained database of stress injuries involving basic combat trainees from a single military post was reviewed over a 3-year period. Inclusion criteria included basic trainees undergoing surgery for a femoral neck stress fracture between January 2018 and June 2020 with a minimum of 1-year follow-up. Surgery was indicated for service members with complete and tension-sided femoral neck stress fractures and those with high risk compression-sided stress fractures, generally representing fractures involving more than 50% of the femoral neck width. Over the study period, 57 service members (51% [29 of 57] women with a mean age of 24 years) underwent surgery for a femoral neck stress fracture, and all 57 had a minimum of 1-year follow-up. Identified service members underwent independent data collection including injury and radiographic parameters based on chart and imaging review. Documented fracture line progression on repeat imaging was present in 39% of service members, with a mean fracture line progression of 55% of the femoral neck width. Service members were subdivided based upon the ability to return to military service at 1 year. Univariate analysis was performed using patient and injury variables to identify factors associated with the ability to return to military service. Overall, 58% (33 of 57) of service members who had a femoral neck stress fracture treated surgically underwent military separation. A higher proportion of service members who demonstrated fracture line progression leading to surgical treatment remained in the military (58% [14 of 24] versus 30% [10 of 33]; odds ratio 0.3 [95% confidence interval (CI) 0.1 to 0.9]; p = 0.03). With the numbers available, we found no other patient- or fracture-related variables associated with military separation, although we suspect we may have been underpowered on some of these comparisons, in particular gender (61% [20 of 33] of individuals separated after surgery for this injury were women compared with 38% [9 of 24] who were retained; OR 2.6 [95% CI 0.9 to 7.56]; p = 0.09). The extent of osseous edema on T1-weighted imaging in association with a hip effusion demonstrated a significant positive correlation with final fracture percentage (r = 0.62; p = 0.003). Military service members with a femoral neck stress fracture initially managed nonoperatively but with progression of the fracture line requiring surgical intervention were more likely to return to military duties and complete basic combat training, suggesting that early diagnosis of femoral neck stress fractures may be associated with better functional recovery after surgical treatment. Additionally, the extent of the osseous edema on initial MRI T1-weighted imaging sequences may help predict the final extent of femoral neck stress fractures on repeat imaging. Further investigations should incorporate patient-reported outcomes and further explore factors associated with fracture progression and the inability to return to active duty or sport. Level III, therapeutic study.

Femoral Neck Stress Fractures: An Updated Review.

Femoral neck stress fractures represent a relatively rare spectrum of injuries that most commonly affect military recruits and endurance athletes. If unrecognized and if proper treatment is not initiated, this condition carries potentially devastating consequences. Patients will typically present with an insidious onset, atraumatic hip, and groin pain that is relieved with rest. The condition may be initially misdiagnosed because radiographs are often normal. Magnetic resonance imaging has demonstrated superior specificity, sensitivity, and accuracy compared with other diagnostic modalities in identifying and classifying stress fractures of the femoral neck. Treatment algorithms are based on the MRI fracture morphology and presence of an intra-articular effusion. Nonsurgical management consists of a period of non-weight-bearing followed by gradual return to activity. Surgical management consists of prophylactic fracture fixation with cannulated screws to prevent fracture progression. If left untreated, patients may progress to a complete displaced femoral neck fracture, which can be associated with complications that include nonunion, osteonecrosis of the femoral head, and long-term disability. These poor outcomes emphasize the importance of early diagnosis and treatment of incomplete femoral neck stress fractures.

Avascular necrosis of the femoral head following an occult femoral neck stress fracture

Introduction. Osteonecrosis (ON) of the femoral head (FH) ? (ONFH) is an intractable disease that causes progressive femoral head collapse, severe pain, and gait disturbance. We report a case of avascular necrosis of the femoral head following an occult femoral neck (FN) stress fracture. Case report. A 55-year-old woman presented to our department with a chief complaint of low back pain that radiated into the left anterolateral thigh over the period of two months. Her left anterolateral thigh became progressively more painful over the past two weeks. No abnormal findings indicative of ONFH or an occult fracture of the FN were detected by X-ray or computed tomography, but an occult insufficiency fracture of the left FN was identified on magnetic resonance imaging (MRI). The diagnosis of FN stress fracture was delayed, resulting in femoral head necrosis. The fracture was treated with total hip arthroplasty, and the resected FH was subjected to histopathology (HP). Based on the HP findings, the final diagnosis of this case was ONFH with an occult fracture of the left FN. Clinical symptoms were relieved postoperatively. Conclusion. An early MRI examination is recommended in patients presenting with a suspected stress fracture of the FN to avoid FH necrosis due to a delayed diagnosis.