title: Calcaneal stress fracture: an adverse event following total hip and total knee arthroplasty: a report of five cases.
abstract: BACKGROUND
  Stress fractures have been reported to occur in the pubis, femoral neck, proximal part of the tibia, and fabella during the postoperative period following total knee or total hip arthroplasty. However, to our knowledge, calcaneal stress fractures after total hip or total knee arthroplasty have not been reported in the English-language literature. Most orthopaedic surgeons are not familiar with calcaneal stress fractures that may occur in elderly patients after a total knee or total hip arthroplasty.
  
  
  METHODS
  We retrospectively reviewed the clinical features, imaging findings, and bone mineral content of the proximal part of the femur and the distal end of the radius in five patients who had a calcaneal stress fracture after a total knee or total hip arthroplasty.
  
  
  RESULTS
  All patients were women with a mean age of 76.8 years. All fractures occurred in the calcaneus on the same side as the arthroplasty. The fracture appeared at a mean of 10.2 weeks postoperatively. All patients reported heel pain on walking. Swelling and local heat were found in four and three patients, respectively. Pain was elicited by squeezing the calcaneus in all patients. Early radiographs had normal findings in two patients, and an irregular sclerotic line appeared later in the radiographs of all patients. All fractures were treated conservatively. Four fractures healed uneventfully, but one fracture displaced. All patients had osteoporosis.
  
  
  CONCLUSIONS
  Calcaneal stress fractures during the postoperative period following total knee or total hip arthroplasty may not be as rare as previously thought. Because clinical symptoms of the fracture appear insidiously and radiographic findings are absent or subtle in the early stage, a high index of suspicion is needed for orthopaedic surgeons to make the correct diagnosis. Magnetic resonance imaging or repeated radiographs may be necessary to make the correct diagnosis when no abnormality is apparent on the initial radiograph.
authors.affiliation: Department of Orthopedic Surgery, Unnan Municipal Hospital, Iida 96-1, Daito Town, Unnan City, Shimane Prefecture 699-12, Japan. E-mail address for T. Miki: t.miki@hotaru.yoitoko.jp. E-mail address for A. Nishiyama: akihiron@hotaru.yoitoko.jp.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Miki
authors.affiliation: Miki Orthopedic and Pain Clinic, Kandachi 706, Aikawa, Hikawa-Town, Izumo City, Shimane Prefecture 699-0615, Japan. E-mail: t.m.gomimushiman@yahoo.ne.
authors.forename: Takahito
authors.initials: T
authors.lastname: Miki
authors.affiliation: Department of Orthopedic Surgery, Unnan Municipal Hospital, Iida 96-1, Daito Town, Unnan City, Shimane Prefecture 699-12, Japan. E-mail address for T. Miki: t.miki@hotaru.yoitoko.jp. E-mail address for A. Nishiyama: akihiron@hotaru.yoitoko.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishiyama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D015519:Bone Density / Q000502:physiology; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000379:methods; D017102:Fracture Healing / Q000502:physiology; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D015775:Fractures, Stress / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D006801:Humans; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D018570:Risk Assessment; D012494:Sampling Studies; D016896:Treatment Outcome