title: Distribution of hip pain in patients with idiopathic osteonecrosis of the femoral head.
abstract: OBJECTIVE
  To determine the distribution of referred hip pain in patients with idiopathic osteonecrosis of the femoral head (ION).
  
  
  METHODS
  We prospectively documented 119 hips in 90 patients with ION (mean age 51 years). Patients identified the location of pain originating in their hip on a drawing of the body. Osteoarthritis of the hip (OA) was used as a historical cohort.
  
  
  RESULTS
  Referral of pain originating from the hip in patients with ION was 93% (111 hips) to the groin, 68% (81 hips) to the knee, 36% (43 hips) to the anterior thigh, 34% (40 hips) to the buttock, 18% (22 hips) to the lower leg, 9% (11 hips) to the greater trochanter, and 8% (9 hips) to the low back. About 97% (115 hips) of pain was located in the hip region (groin, buttock, and greater trochanter) and 77% (92 hips) showed referred pain (anterior thigh, knee, lower leg, and low back). Pain from ION was significantly more frequent in the knee and lower leg, but significantly less frequent in the lower back than pain from OA.
  
  
  CONCLUSIONS
  We should be aware of ION masquerading as pain in the knee or anterior thigh.
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Nakamura
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Konno
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Orita
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hagiwara
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Shigemura
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Takane
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Akagi
authors.affiliation: a Department of Orthopaedic Surgery, Graduate School of Medicine , Chiba University , Chiba City , Chiba , Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D005271:Femur Head Necrosis / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000150:complications / Q000175:diagnosis*; D020370:Osteoarthritis, Knee / Q000150:complications / Q000175:diagnosis*; D010146:Pain / Q000175:diagnosis* / Q000209:etiology
keywords: Distribution of hip pain; Idiopathic osteonecrosis of the femoral head; Referred pain