We present two patients who developed multiple lower limb stress fractures. Potential causes, such as osteoporosis, malignancies and disturbances in calcium metabolism were investigated. This led the physicians to consider whether methotrexate (MTX) exposure posed a risk of atypical fractures.The association between MTX and lower limb fractures has been described in at least 80 cases in the literature. Stress fractures associated with MTX treatment are atypical of osteoporosis and located in the lower extremities, most often the tibia. The limited data suggest that discontinuation of MTX may improve symptoms and chances of fracture healing, while antiresorptive or osteoanabolic therapies have not proven clinically efficient. It seems evident, however, that the benefits of MTX treatment in rheumatological disease clearly outweigh the risk of MTX osteopathy and related fractures.

BACKGROUND: Periprosthetic fractures (PPF) are rare complications of total knee arthroplasty (TKA). The most common PPF after TKA is supracondylar femoral fracture, which is a relatively rare complication that is usually associated with high-energy trauma, with a reported incidence ranging from 0.4 to 1.7% according to the AOANJRR. However, in TKA patients, it is rarer that the stress fracture around the tibial prosthesis occurs due to changes in the lower limb force line, increasing weight-bearing, and changes in walking gait.
METHODS: A 68-year-old woman visited our hospital with \"both knees had aggravated pain and deformity for 8 years.\" TKA was performed first on the left knee and the patient was discharged within 1 week. Three months later, the patient complained of pain in the upper middle 1/3 part of the medial tibia for 2 weeks, which gradually worsened and affected weight-bearing.
METHODS: Physical examination showed that the left knee joint presented varus deformity, and the right valgus deformity, which diagnosed as osteoarthritis of both knees and was so-called \"blownknee\". The disease was initially diagnosed as osteoarthritis of both knees on first admission and PPF of the tibia in second.
METHODS: Three operations were performed on this patient. The first was TKA of the left knee, the second was open reduction and internal fixation of the PPF of the tibia 3 months after the first operation, and the third was TKA of the right knee.
RESULTS: Until now, the patient has had no recurrent PPF, and the fracture is healing from the last X-ray.
CONCLUSIONS: Clinicians should be aware of the possibility of PPF after TKA, especially in such patients, the most preferred surgical treatment method was open reduction and internal fixation of fractures using locking plates, and if the PPF with loosened implants, Revision TKA, or megaprosthesis was the better choice.

UNASSIGNED: Previous studies have reported that spondylolysis occurs predominantly at the L5 and L4 levels, with defects at higher levels occurring in <5% of cases. However, computed tomography and radiography were the primary imaging modalities in these studies. Current evidence regarding diagnostic imaging for pediatric lumbar spondylolysis suggests that magnetic resonance imaging (MRI) is as accurate as computed tomography in detecting early stress reactions of the pars interarticularis or pedicles without fractures while avoiding radiation exposure. The early detection of spondylolysis results in a higher likelihood of bony union and a decreased likelihood of spondylolisthesis.
UNASSIGNED: The increased use of MRI may reveal a larger proportion of spondylolysis in patients who experience an injury at a higher spinal level than previously reported.
UNASSIGNED: Cross-sectional study; Level of evidence, 3.
UNASSIGNED: The medical records of 902 pediatric and adolescent athletes (364 female, 538 male) diagnosed with symptomatic pars interarticularis and pedicle stress injuries at 2 academic medical centers between 2016 and 2021 were retrospectively reviewed. All patients had MRI scans taken at the time of diagnosis. Only patients with pars/pedicle edema on MRI were included. Data regarding spondylolysis stage, spinal level of injury, unilateral versus bilateral injury, sport participation, and MRI protocol over the 5-year study period were analyzed.
UNASSIGNED: Male patients presented at older ages than female patients (P < .001). Soccer was the most common sport at symptom onset and the second most common single-sport activity among those who specialized (participating in 1 sport year-round at the exclusion of others), behind gymnastics. The mean symptom duration was 4.0 months. Although most patients (83.5%) had exclusively lower lumbar stress injuries, 9.1% of injuries occurred at or above the L3 level. Over half of the patients had active single-level pars/pedicle fractures on MRI, with a mean symptom duration before presentation in this subgroup of 4.0 months. Even when pars/pedicle stress reactions were excluded from analysis, 7.1% of patients were injured at or above the L3 level.
UNASSIGNED: Among male and female athletes aged 8 to 21 years presenting with symptomatic pars interarticularis and pedicle stress injuries evaluated by MRI at the time of initial diagnosis, there was a higher incidence of upper lumbar stress injuries than previously reported.

The study aimed to evaluate whether the measurement of Femoral Neck Shaft Angle (FNSA) can be helpful in differentiating femoral head Stress Fracture (SF) from Avascular Necrosis (AVN).
From September 2019 to April 2022, sixty-four patients [median age 32.0 years, interquartile range (IQR) 23.0-39.0 years] who underwent both hip radiograph and Magnetic Resonance Imaging (MRI) and diagnosed as femoral head SF or AVN were included in our retrospective study. Patients were divided into as having either femoral head SF (n = 34) or AVN (n = 30). The FNSA was measured in anteroposterior hip radiography. Continuous values were compared using the Mann-Whitney U test. The assessment of the predictive value of FNSA for femoral head SF was performed by Receiver Operating Characteristic (ROC) analysis.
The FNSA was significantly higher in patients with SF (median 133.5°, IQR 128.0-136.7°) than those with AVN (median 127.5°, IQR 124.0-132.0°) (p = 0.001). In addition, the FNSA was significantly higher in SF femurs (median 134.8°, IQR 129.2-137.4°) than in contralateral normal femurs (median 127.1°, IQR 124.3-132.5°) in patients with unilateral femoral head SF (n = 30) (p < 0.001). In ROC analysis, the sensitivity, specificity, and Area Under the Curve (AUC) for predicting the femoral head SF were 77.3%, 63.3%, and 0.785 (95% confidence interval: 0.666-0.905), respectively, at a cutoff of 130.2°.
Increased FNSA was associated with femoral head SF; thus, measurement of FNSA could be helpful for differentiating femoral head SF from AVN.

To determine the diagnostic yield of cone beam computed tomography (CBCT) compared with 3 T magnetic resonance imaging (MRI) for the evaluation of subchondral insufficiency fractures of the knee. Consecutive patients with subchondral insufficiency fractures of the knee examined by 3 T MRI and CBCT of the femoral condyles were reviewed. Two experienced raters graded the lesion severity on 3 T MRI and CBCT images: grade 1: no signs of a subchondral bone lesion; grade 2: subchondral trabecular fracture or cystic changes, but without infraction of the subchondral bone plate; grade 3: collapse of the subchondral bone plate. Ratings were repeated after six weeks to determine reliability. In addition, the bone lesion size was measured as elliptical area (mm2) and compared between CBCT and T1-weighted MRI sequences. Among 30 patients included (43.3% women; mean age: 60.9 ± 12.8 years; body mass index (BMI) 29.0 ± 12.8 kg/m2), the medial femoral condyle was affected in 21/30 patients (70%). The grading of subchondral lesions between MRI and CBCT did not match in 12 cases (40%). Based on MRI images, an underestimation (i.e., undergrading) compared with CBCT was observed in nine cases (30%), whereas overgrading occurred in three cases (10%). Compared to CBCT, routine T1-weighted 3 T sequences significantly overestimated osseus defect zones in sagittal (84.7 ± 68.9 mm2 vs. 35.9 ± 38.2 mm2, p < 0.01, Cohen\'s d = 1.14) and coronal orientation (53.1 ± 24.0 mm2 vs. 22.0 ± 15.2 mm2, p < 0.01, Cohen\'s d = 1.23). The reproducibility of the grading determined by intra- and inter-rater agreement was very high in MRI (intra-class correlation coefficient (ICC) 0.78 and 0.90, respectively) and CBCT (ICC 0.96 and 0.96, respectively). In patients with subchondral insufficiency fractures of the knee, the use of CBCT revealed discrepancies in lesion grading compared with MRI. These findings are clinically relevant, as precise determination of subchondral bone plate integrity may influence the decision about conservative or surgical treatment. CBCT represents our imaging modality of choice for grading the lesion and assessing subchondral bone plate integrity. MRI remains the gold standard modality to detect especially early stages.

Sjogren\'s syndrome is a known cause of renal tubular acidosis (RTA). However, osteomalacia associated with Sjogren\'s syndrome is rare and seldom reported in literature. We report a case of pseudofractures of both femora due to osteomalacia as a result of RTA secondary to Sjogren\'s syndrome, which was initially misdiagnosed as a stress fracture. A man in his 30s presented with hip pain and was initially misdiagnosed to have stress fractures because of the \'through and through\' extension of the \'fracture\' lines at the neck of both femora. The patient had a normal serum biochemistry profile except for elevated alkaline phosphatase levels. On further evaluation, he was found to have distal RTA secondary to Sjogren\'s syndrome. The patient responded to sodium bicarbonate therapy with clinical, biochemical and radiological improvement. A high index of suspicion for RTA should be kept in a patient with osteomalacia with a normal calcium profile and vitamin D level.

UNASSIGNED: A 21-year-old African American Division 1 female sprinter presented with 3-weeks history of right great toe and forefoot pain, fatigue, and a 30-day continuous menstrual cycle despite implanted etonogestrel (Nexplanon) inserted 3 years prior. An magnetic resonance imagine (MRI) identified likely stress fracture of the second metatarsal base with a diffusely low T1 signal indicating hyperactive red marrow. Due to persistent pain, a follow-up MRI was ordered 6 months later and indicated serous atrophy of the bone marrow, prompting a further metabolic workup notable for triglycerides exceeding 4000 mg/dL and a hemoglobin A1c of 10.9%. This case highlights the manifestation of a rare congenital lipodystrophy that initially presented as a relatively classic stress fracture and metrorrhagia in a female athlete.

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UNASSIGNED: Subchondral fractures are a common cause of joint pain that may ultimately lead to articular collapse and the need for arthroplasty. This type of fracture has been reported at multiple joints throughout the body. While clinical and radiographic resolution can be achieved, progressive bone collapse can occur and lead to a variety of complications. Understanding the pertinent imaging findings can aid in the early evaluation of subchondral fractures and in the prevention of their associated complications.

UNASSIGNED: The purpose of this study was to evaluate functional outcomes, radiologic results, and complications after hybrid total hip arthroplasty (THA) in patients with subchondral insufficiency fractures (SIFs) of the femoral head.
UNASSIGNED: From June 2009 to December 2020, among 985 patients who underwent hybrid THA at our hospital, 19 patients diagnosed with SIF through a retrospective chart review were included. Those under 50 years of age, with radiographic findings of osteonecrosis on the contralateral side of surgery, a history of organ transplantation, and alcohol abuse, were excluded. Functional evaluation was performed using a modified Harris Hip Score (HHS). After surgery, inclination and anteversion of the acetabular cup and version of the femoral system were measured using postoperative x-ray. The outpatient follow-up was performed at 6 weeks, 3 months, 9 months, and 12 months after surgery and every year thereafter. Complications including dislocation, implant loosening, stem subsidence, and periprosthetic infection were observed on follow-up radiographs.
UNASSIGNED: The average follow-up time was 29.3 ± 9.1 months (range, 24-64 months) with no loss to follow-up. The mean modified HHS was 83.4 ± 9.6 (range, 65-100) at the last outpatient clinic follow-up. The average inclination of the acetabular cup was 41.9° ± 3.4° (range, 37°-48°), and the anteversion was 27.5° ± 6.7° (range, 18°-39°). The version of the femoral stem was 19° ± 5.7° (range, 12°-29°). There was no case of intraoperative fracture. There were no cases of dislocation, loosening of the cup, subsidence of the femoral stem, intraoperative or periprosthetic fracture, or periprosthetic infection on the follow-up radiographs.
UNASSIGNED: In our study, hybrid THA showed favorable outcomes in patients diagnosed with SIF, and there were no further special considerations as for THA performed due to other diseases or fractures.