title: Quadriceps tendon rupture in maintenance haemodialysis patients:  results of surgical treatment and analysis of risk factors.
abstract: BACKGROUND
  Reports of spontaneous quadriceps ruptures in end-stage renal disease (ESRD) patients are scarce, and the assessment of risk factors for tendon rupture is poorly addressed in the majority of the studies. The purpose of the present study is to report a series of patients on haemodialysis with spontaneous quadriceps tendon ruptures operated at our institution. The results of the surgical treatment are described and the potential risk factors associated with the rupture are analyzed.
  
  
  METHODS
  Our study consisted of retrospective analysis of patient's charts. Clinical and laboratory findings of the operated group were compared to the ones of a control group of haemodialysis patients matched by age, gender, and time on haemodialysis, but without tendon rupture.
  
  
  RESULTS
  Between 1998 and 2010, six ESRD patients with 11 spontaneous ruptures of the quadriceps tendon were treated at our institution. On postoperative evaluation all patients were able to walk without crutches after six months of follow-up, and there were no new ruptures. Positive serology for Hepatitis C was present in two cases (33%) but in none of the controls (p = 0.034). Mean serum levels of intact parathormone (iPTH) and alkaline phosphatase were both higher in cases (p = 0.013 and p = 0.034, respectively). In contrast, mean serum levels of albumin, ferritin and haemoglobin were all lower in cases (p = 0.008, p = 0.043 and p = 0.016, respectively).
  
  
  CONCLUSIONS
  Reconstructive surgery is a good way to restore knee function in ESRD patients with quadriceps tendon ruptures. Our cases exhibited higher levels of iPTH and alkaline phosphatase than control patients, reinforcing the role of secondary hyperparathyroidism in tendon weakening. They also had a higher frequency of hepatitis C and lower levels of albumin and haemoglobin compared to controls, possibly implicating chronic inflammation as a potential risk factor for tendon rupture.
authors.forename: Luis Marcelo A
authors.initials: LM
authors.lastname: Malta
authors.forename: Vinicius S
authors.initials: VS
authors.lastname: Gameiro
authors.forename: Elisa A
authors.initials: EA
authors.lastname: Sampaio
authors.forename: Maria E
authors.initials: ME
authors.lastname: Gouveia
authors.forename: Jocemir R
authors.initials: JR
authors.lastname: Lugon
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D052097:Quadriceps Muscle / Q000293:injuries / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D006435:Renal Dialysis; D012189:Retrospective Studies; D012307:Risk Factors; D012422:Rupture, Spontaneous; D013710:Tendons / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D010281:Parathyroid Hormone