Page 60 - The value of total hip and knee arthroplasties for patients

Chapter 4
For each item, patients could indicate their expectations on a 5-point Likert scale. One year postoperatively, the same questionnaire was completed, but at that time, patients were asked the perceived actual outcome of all the items listed in the preoperative expectation questionnaire, using the same answering categories (Appendix). Patients were not informed about their preoperative answers/scores at the follow-up assessment.
Surgical Techniques
In THA surgeries, 2 different surgical approaches were used: straight lateral in lateral position of the patient and the anterior approach (anterior supine intermuscular) in supine position of the patient. Only uncemented cups (RingLoc, Biomet) and uncemented stems were used (Mallory-Head and Taperloc, Biomet). The joint surface was polyethylene with a ceramic head, usually 28 mm. The total knee prosthesis used concerns are the NexGen (Zimmer), posterior stabilized; both the femoral and tibia component were cemented.
Statistical Analysis
Descriptive statistics were used for the preoperative sociodemographic and clinical characteristics, as well as for the scores on the expectation questionnaires.To assess potential selection due to attrition, baseline characteristics of patients with and without complete follow-up were compared by means of the Mann-Whitney U test or chi-square test.To compute fulfillment of expectations 1 year after surgery, for each item of the HSS expectation survey, the postoperative score was subtracted from the preoperative score for each individual patient. A negative fulfillment score indicated less improvement than expected, a score of zero indicated an outcome as expected, and a positive score indicated a greater improvement than expected. When a patient used the answering category “not applicable” in either the preoperative or postoperative questionnaire or both, a fulfilment score was not calculated for that item. For each HSS expectation item, the frequencies of unfulfilled, fulfilled, and exceeded expectations were calculated in both THA and TKA patients.All data were analyzed using the SPSS statistical package (version 20.0, SPSS, Chicago, IL). All analyses were performed separately for THA and TKA groups.
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