title: Hamate hook nonunion initially mistaken for ulnar nerve compression: a case report with review of literature.
abstract: BACKGROUND
  Hamate hook (HH) stress fractures are rare, often presenting with misleading symptoms and easily overlooked/misdiagnosed. These fractures occur frequently in individuals participating in sports activities involving racquets, bats, or clubs. Symptoms are non-specific and often mimic other clinical conditions, such as ulnar nerve entrapment or ulnar vessel thrombosis.
  
  
  METHODS
  A 17-year-old tennis player with no history of trauma presented with dominant hand weakness together with pain and paresthesia on the ulnar side, which exacerbated with tennis play. The patient was treated for ulnar nerve compression with activity cessation and rest for 2 months. After 6 months of persistent symptoms, the patient underwent open Guyon tunnel release, although preoperative electromyoneurography revealed no signs of nerve damage and bone scans showed a small area of increased uptake in the hypothenar region. Postoperatively, symptoms resumed and the patient reported to our department for a second opinion. Point tenderness over HH, hypothenar muscles hypotrophy, paresthesia, hand weakness and pain with ulnar deviation, and flexion of distal phalanges of the two ulnar fingers were observed. HH fracture was suspected. Computerized tomography scan revealed fractured HH and the patient underwent hook excision. One month postoperatively, the pain intensity reduced together with function and strength improvement; 2 months postoperatively, the patient was pain free and had returned to tennis.
  
  
  CONCLUSIONS
  In patients involved in racquet sports with hypothenar pain and paresthesia of the ulnar side of the hand, HH fracture should be suspected. Symptoms can mimic ulnar nerve entrapment and may lead to overlooking the correct diagnosis. Treatment of choice is fractured fragment excision.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Center Zagreb, University of Zagreb School of Medicine, Salata 6-7, 10000, Zagreb, Croatia.
authors.forename: Mario
authors.initials: M
authors.lastname: Josipovic
authors.affiliation: Department of Gastroenterology, University Hospital Centre Split, Spinciceva 11, 21000, Split, Croatia.
authors.forename: Dorotea
authors.initials: D
authors.lastname: Bozic
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Center Zagreb, University of Zagreb School of Medicine, Salata 6-7, 10000, Zagreb, Croatia. ivan.bohacek@gmail.com.|Department of Anatomy and Clinical Anatomy, University of Zagreb School of Medicine, Salata 11, 10000, Zagreb, Croatia. ivan.bohacek@gmail.com.
authors.forename: Ivan
authors.initials: I
authors.lastname: Bohacek
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Center Zagreb, University of Zagreb School of Medicine, Salata 6-7, 10000, Zagreb, Croatia.|The Elective Orthopaedic Centre, Epsom, Surrey, UK.
authors.forename: Tomislav
authors.initials: T
authors.lastname: Smoljanovic
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Center Zagreb, University of Zagreb School of Medicine, Salata 6-7, 10000, Zagreb, Croatia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Bojanic
mesh_terms: D000293:Adolescent; D003937:Diagnosis, Differential; D017759:Fractures, Malunited / Q000175:diagnosis* / Q000601:surgery*; D015775:Fractures, Stress / Q000175:diagnosis* / Q000601:surgery*; D051225:Hamate Bone / Q000293:injuries* / Q000601:surgery*; D006801:Humans; D008297:Male; D013715:Tennis / Q000293:injuries*; D017769:Ulnar Nerve Compression Syndromes / Q000175:diagnosis / Q000601:surgery
keywords: Hamate hook excision; Hamate hook fracture; Hamate hook nonunion; Tennis; Ulnar nerve compression