Identification of Risk Factors of Prolonged Wound Healing Following Primary Arthroplasty
Condition: Evaluate Surgical, Medical and Pharmacological Factors Influence on Wound Healing Following Primary Arthroplasty Surgery
MeSH terms: Wounds and Injuries
Study type: Observational

Summary: 
      Prolonged wound drainage following total joint replacement surgery has been shown to be a
      predictor of postoperative infection. Several factors have been associated with delayed wound
      healing and increased risk of infection. Namely hypertension, obesity, diabetes, smoking and
      autoimmune disease have been shown to have a detrimental effect on wound healing. The purpose
      of this study is to verify those findings and determine additional pharmacological, surgical
      and patient related factors that may result in prolonged wound drainage, prolonged hospital
      stay and increased risk of infection
    

Detailed description: 
      Study type: Prospective cohort study. Inclusion criteria: All patients receiving primary
      total hip or knee replacement surgery at Hvidovre Hospital from January 1st 2012 to December
      31st 2014.

      Exclusion criteria: none Intervention: none

      New hypothesis to be tested:

        1. Hypertension is associated with prolonged wound drainage and increased risk of infection

        2. Patients receiving Statin treatment have decreased postoperative wound drainage and
           decreased risk of infection.

        3. Patients receiving Bisphosphonate treatment have increased postoperative wound drainage
           and increased risk of infection.

      Measured patient related risk variables: Age, sex, primary OA diagnosis, diabetes, smoking,
      BMI, alcohol consumption, autoimmune disease and hypertension will all be recorded upon
      admission of the patient to the hospital. Hypertension will be defined when a patient is
      diagnosed with HT previously to the surgery, receives medical treatment and have systolic /
      diastolic BP above 140/90 mmHg upon admission. Patients with normal BP upon admission
      receiving treatment for HT will be classified as having regulated HT. Patients with elevated
      BP upon admission without previous HT diagnosis will be classified as having newly diagnosed
      HT. "Smoking" will de divided into smokers, non-smokers and former smokers. Further on,
      average number of cigarettes pr day during the last month will be recorded for current
      smokers.

      Measured pharmacological risk variables: Use of statins, bisphosphonates, anticoagulants,
      NSAID's and corticosteroids on time of admission will be recorded.

      Measured surgical risk variables: Surgery time, pneumatic tourniquet time, peroperative blood
      loss, postoperative decrease in hemoglobin levels, surgical complications, antibiotic and
      bleeding prophylaxis will be recorded by the surgeon upon completion of the surgery.

      Outcome measures: Wound-oozing time, length of hospital stay, wound infections, and surgical
      revision. Wound will be defined as actively draining if the gauze covering the wound is wet
      to the edges or if fluid is noted to be originating from the surgical site. The nursing staff
      will record wound drainage during the hospital stay and the patient will be instructed in
      self-assessment upon dismissal using patient-diary. Wound drainage will be recorded twice a
      day: before- and afternoon. All patients are seen in outpatient clinic for staple removal and
      control of the self -assessment drainage-diary 3 weeks after surgery. Time when the wound
      appeared dry will be noted. Presence or absence of clinical infection will be noted according
      to ASEPSIS criteria.

      Statistical analysis: Multiple linear regression analysis will be performed to model the
      effects of the measured risk variables on the time to a dry wound, length of hospital stay
      and risk of wound infection.

      Data collection: All data collection will be anonymous. Patient consent is not required since
      the study involves evaluation of existing data and records and individual subjects can not be
      identified either directly or through identifiers linked to the subject. The data collection
      will be reported to "Datatilsynet".
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        All patients receiving primary hip or knee arthroplasty at Hvidovre Hospital from january
        2012 to january 2014.