About

Hamza S. Alizai, MD, is an Adjunct Assistant Professor of Radiology at the University of Pennsylvania. He serves as an Attending Radiologist at the Children's Hospital of Philadelphia in the Department of Radiology, Division of Musculoskeletal (MSK) and Body Imaging, and is also a Staff Radiologist at the Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center, specializing in Musculoskeletal Imaging. Dr. Alizai completed his undergraduate studies in Psychobiology at Binghamton University, State University of New York, in 2006, and earned his MD from Ross University School of Medicine in 2010.

Research topics

• Medicine
• Radiology
• Nuclear medicine
• Physical therapy
• Anatomy

Selected publications

• Pediatric musculoskeletal ultrasound of the elbow: a pictorial review

  Pediatric Radiology · 2026-03-20

  articleOpen access1st authorCorresponding

  The elbow is a complex joint consisting of three separate articulations: ulnotrochlear, radiocapitellar, and proximal radioulnar. Collectively, these allow movements including flexion, extension, supination, and pronation. The developing pediatric elbow can be challenging to assess due to the predominance of cartilaginous epiphyseal and apophyseal structures, which are not evident on radiographs. Although MRI provides a comprehensive assessment of elbow anatomy, it can also be technically challenging. In a supine position with the arm to the side, the off-center position of the elbow can lead to decreased image quality due to magnetic field inhomogeneity with low signal-to-noise ratio (SNR) and poor fat suppression. Positions that attempt to bring the elbow to the MR iso-center can be uncomfortable in children suffering from elbow pain, leading to motion artifact. Furthermore, many of the soft tissue pathologies in the elbow are dynamic in nature and are best assessed using dynamic maneuvers. Ultrasound (US) is an ideal imaging modality for both static and dynamic assessment of the pediatric elbow joint and its soft tissue stabilizers. Additionally, comparison with the US of the contralateral elbow can serve as an internal control in the assessment of skeletally immature patients. In this narrative review, we describe the ultrasound technique for evaluating the pediatric elbow, the normal sonographic anatomy, and the common pathologies that may be encountered in practice.

  PublisherOA PDFDOI

• Lateral discoid meniscus in the pediatric knee: imaging features and tear patterns

  Skeletal Radiology · 2026-02-12

  article
  PublisherDOI

• Prevalence of Asymptomatic Acetabular Labrum Abnormalities in the Active Pediatric Population

  Journal of Pediatric Orthopaedics · 2025-01-30 · 3 citations

  articleCorresponding

  BACKGROUND: The prevalence of labral tears in asymptomatic active adults has been reported, but the prevalence of labral tears and other incidental hip lesions in the asymptomatic active pediatric population remains unclear. The purpose of this study was to determine the prevalence of hip abnormalities detected on 3T MRI in an active pediatric population with no hip symptoms and to compare with hip abnormalities found in children and adolescents who underwent an MRI for a hip-related condition. METHODS: After IRB approval, pediatric patients self-reporting as athletes and presenting with isolated, acute-onset knee pain requiring knee MRI were prospectively recruited to undergo 3T MRI of their asymptomatic contralateral hip (ASx). A comparison group of pediatric subjects who underwent an MRI for hip pain was enrolled retrospectively (Sx). All MRI scans were anonymized and randomized. Fifty subjects were enrolled for each cohort. Two fellowship-trained musculoskeletal radiologists independently evaluated MRIs for abnormal hip lesions, including labral tears. Inter-reader reliability was evaluated using Cohen Kappa. χ 2 or Fisher exact test was used to compare the prevalence of hip lesions between the 2 cohorts. RESULTS: The average patient age was 14.9 years for both cohorts (range 9 to 18 y) and 48% were male. In the ASx group, incidental labral tears were found in 18%, labral/paralabral cysts 6%, cartilage lesion 0%, subchondral cyst 0%, ligamentum teres tear 0%, femoral fibrocystic change 0%, cam lesion 30%, acetabular bone edema 0%, acetabular rim fracture 0%. The prevalence of labral tears (30%, P -value 0.16) and cam lesion (36%, P -value 0.52) in the Sx group was not significantly different from the ASx cohort. No significant correlation was found between the presence of femoral neck osseous bump and labral tear, labral cyst, or paralabral cyst in either cohort. CONCLUSIONS: Labral tears were present on 3T MRIs of active pediatric patients with and without hip pain. Although MRI is essential to confirm the surgeon's suspicion and to detect unexpected pathology, clinical examination and history are crucial in pinpointing clinically relevant abnormal imaging findings. LEVEL OF EVIDENCE: Level III.

  PublisherDOI

• Subspecialty training in pediatric musculoskeletal imaging: an innovative approach to outreach, collaboration, and faculty development

  Pediatric Radiology · 2025-02-17

  letter
  PublisherDOI

• Osteoblastoma involving the sphenoid bone diagnosed with percutaneous biopsy

  Skeletal Radiology · 2025-05-24

  review
  PublisherDOI

• Imaging Assessment of the Pediatric Elbow: Developmental Variants and Common Pathologies

  Seminars in Musculoskeletal Radiology · 2024-07-29 · 3 citations

  review

  The pediatric elbow is a complex joint that undergoes rapid growth and development. The normal anatomy of the elbow varies depending on the age of the patient, which can be challenging for imaging interpretation. This article reviews developmental variants and common pathologies of the pediatric elbow, with a focus on their radiologic features. Normal anatomy and development of the pediatric elbow are discussed, including the six ossification centers and elbow alignment. Congenital anomalies such as longitudinal deficiencies of the upper extremity are reviewed. Some common injuries that affect the elbow, such as supracondylar fracture, lateral condyle fracture, medial epicondyle avulsion, and radial head dislocation are also described.

  PublisherDOI

• Ultrasonographic humeral retrotorsion comparisons in youth gymnasts

  JSES International · 2024-11-27

  articleOpen access

  Background: Humeral retrotorsion has been studied in youth baseball but is underexplored in other upper-extremity sports. Gymnasts, who often perform repetitive tumbling and overhead weight bearing, are at risk for shoulder pain and impingement. It is unclear if humeral torsional remodeling contributes to these shoulder conditions. The purpose of this study is to compare humeral retrotorsion in the dominant and nondominant arms of female gymnasts vs. nonupper extremity athletes. Methods: Data were drawn from a prospective upper extremity ultrasound registry including female gymnasts and nonupper extremity female athletes (soccer players) aged 8-14 years with open physes, presenting between March 2021 and July 2023. Exclusion criteria were prior upper extremity surgery and metabolic bone disease. Bilateral humeral torsion was measured by a fellowship-trained physician using validated ultrasound methods. Analyses included chi-square and Mann-Whitney tests. Results: = .228) between groups. Conclusion: Youth gymnasts did not exhibit significant humeral retrotorsion differences compared to controls, suggesting shoulder syndromes in gymnasts may relate more to soft tissue adaptations than bony changes.

  PublisherDOI

• Bizarre parosteal osteocondromatous proliferation (BPOP) of the acromion with soft tissue recurrence

  Skeletal Radiology · 2024-03-11 · 1 citations

  articleSenior author
  PublisherDOI

• Poster 119: MRI evidence of labral tears in healthy young athletes without hip pain

  Orthopaedic Journal of Sports Medicine · 2023-07-01

  articleOpen access

  Objectives: The prevalence of labral tears in asymptomatic active adults has been reported, but the prevalence of labral tears and other incidental hip lesions in the asymptomatic adolescent population has not yet been determined. The purpose of this study was to determine the prevalence of hip abnormalities detected on 3T MRI in an active adolescent population with no hip symptoms and, secondarily to compare with hip abnormalities found in adolescents who underwent an MRI for a hip related condition. Methods: Following IRB approval, adolescent patients presenting with isolated knee pain requiring knee MRI were prospectively recruited to have a 3T MRI of their asymptomatic contralateral hip (ASx). A comparison group of adolescent subjects who underwent an MRI for hip pain was enrolled retrospectively (Sx). All MRI scans were anonymized and randomized. Based on preliminary power analysis, 50 subjects were enrolled for each cohort. Blinded to the patient’s cohort status, clinical and demographic data, 2 fellowship-trained musculoskeletal radiologists evaluated these MRI’s independently for abnormal hip lesions, including labral tears. Inter-reader reliability was evaluated using Cohen’s Kappa. A chi-square or Fisher’s exact test was used to compare the prevalence of these hip lesions between the two cohorts. Results: Average patient age was 14.9 years for both cohorts (range 9-18 years); 52% were female. In the ASx group, incidental labral tears were found in 18%, labral/paralabral cysts 6%, cartilage lesion 0%, subchondral cyst 0%, ligamentum teres tear 0%, femoral fibrocystic change 0%, cam lesion 30%, acetabular bone edema 0%, acetabular rim fracture 0%. The prevalence of labral tears (30%, P-value 0.160) and cam lesion (36%, P-value 0.523) in the Sx group was not significantly different from that of the ASx cohort. Conclusions: Labral tears were present on 3T MRI’s of adolescents with and without hip pain. While MRI is essential to confirm the surgeon’s suspicion and to detect unexpected pathology, clinical exam and history are crucial in pinpointing clinically relevant abnormal imaging findings. [Table: see text]

  PublisherOA PDFDOI

• Soft Tissue Cam Impingement in Adolescents: MRI Reveals Impingement Lesions Underappreciated on Radiographs

  The American Journal of Sports Medicine · 2023-11-09 · 7 citations

  article

  Background: Femoroacetabular impingement (FAI) has been described as repetitive and abnormal contact between a structurally abnormal proximal femur (cam) and/or acetabulum (pincer), occurring during the terminal range of motion of the hip. While cam and pincer lesions have traditionally been defined as osseous abnormalities, there may be a subset of adolescent patients whose impingement is primarily soft tissue (nonosseous). The existence of a nonosseous cam lesion in adolescents with FAI has not been well described. Purpose: To identify and characterize a series of adolescent patients with nonosseous (soft cam) FAI identified on magnetic resonance imaging (MRI) and compare these patients’ clinical presentation and outcome with those of a cohort with primary osseous cam FAI in the same age group. Study Design: Case series; Level of evidence, 4. Methods: A prospective institutional registry of patients with symptomatic FAI was reviewed. Patients were included if they had an MRI scan and a lateral radiograph of the hip (45° Dunn or frog) at a baseline visit. On MRI, the anterolateral femoral head was evaluated using radial, coronal, sagittal, or axial oblique sequences. A soft cam lesion was identified by the presence of soft tissue thickening of ≥2 mm at the anterolateral femoral head-neck junction. An alpha angle was measured on MRI scans and radiographs when a lesion was identified. The cohort with soft cam lesions was reviewed and findings and outcomes were compared with those of a cohort with osseous cam lesions. Continuous variables were first examined for normality, and then nonparametric tests—such as the Kruskal-Wallis test—were considered. The change between pre- and postoperative patient-reported outcomes (PROs) was described by mean and standard deviation and evaluated with an independent-samples t test. Results: A total of 31 (9.3%) of 332 hips (mean age, 16.4 years [range 13.1-19.6 years]; women, 83.9%) were identified with a soft tissue impingment lesion on MRI at the femoral head-neck junction between the 12 and 3 o'clock positions. These lesions demonstrated a thickened perichondral ring (71%), periosteal thickening (26%), or a cartilaginous epiphyseal extension (3%). The mean alpha angle on MRI was greater than on radiographs (63.5°± 7.9° vs 51.3°± 7.9°; P < .0001). A total of 22 patients (71%) with soft impingement underwent hip preservation surgery. When compared with patients in the osseous cohort who also underwent surgical management, both groups showed similar significant improvements from pre- to postoperatively (soft: modified Harris Hip Score [mHHS], 26.9 ± 18.2; Hip disability and Osteoarthritis Outcome Score [HOOS], 31.4 ± 22.9; osseous: mHHS, 22.8 ± 20.8; HOOS, 27.4 ± 20.1; P < .0001), with a mean follow-up of 3.4 years (range, 1-7 years) in the soft cam cohort and 3 years (1-10.1 years) in the osseous cam cohort. Conclusion: Clinicians should be aware of nonosseous or soft cam lesions that cause impingement in adolescent patients without an obvious osseous cam on radiographs. MRI is required to detect these soft cam lesions. When nonoperative treatment fails, the PROs in these patients after operative management are comparable with those in patients with osseous cam lesions. Further research is needed to determine whether the soft cam precedes an osseous cam or whether it is a separate entity.

  PublisherDOI

Frequent coauthors

• James Cassuto

  University of Pennsylvania

  49 shared

• Efrosyni Sfakianaki

  University of Miami

  49 shared

• Atishay Jain

  Overlook Medical Center

  49 shared

• Russ Kuker

  Jackson Memorial Hospital

  49 shared

• Sohaib Mohiuddin

  University of Pennsylvania

  49 shared

• Lorenzo Nardo

  University of California Davis Medical Center

  35 shared

• Charles E. McCulloch

  28 shared

• Frank W. Roemer

  Universitätsklinikum Erlangen

  27 shared

Labs

• Hamza S. Alizai LabPI

Education

• Musculoskeletal Radiology Fellowship, Radiology

  NYU Langone Medical Center

  2018

• Diagnostic Radiology Residency, Radiology

  The University of Texas Health Science Center at San Antonio

  2017

• MD

  Ross University School of Medicine

  2017

• BS Psychobiology

  Binghamton University

  2006