Hypoxemia following hospital discharge after fast-track hip and knee arthroplasty - A prospective observational study subanalysis.

BACKGROUND: Post-operative hypoxemia is prevalent in hospitalized patients and may adversely affect recovery. However, little data exist on the post-discharge phase or details on duration, severity and potential risk factors. Thus, we investigated the incidence and risk factors for severe desaturation during the first post-operative week after THA/TKA by continuous nocturnal oxygen saturation monitoring. METHODS: The study was a secondary analysis of a prospective cohort study of 112 patients undergoing fast-track THA/TKA. Patients with known sleep apnoea were excluded. Oxygen saturation and heart rate were recorded by a wireless wrist-worn pulse oximeter 2 nights before and 7 nights after surgery. Data on demographics, opioid consumption and cognitive function were collected from medical charts, patient diaries and clinical testing respectively. The primary outcome was occurrence of severe desaturation defined as periods with saturation <85% lasting ≥10 minutes. Secondary outcomes included description of various saturation levels and relevant risk factors. RESULTS: Severe oxygen desaturation occurred in 35% of the patients during the first post-operative week. Duration and severity of hypoxemic episodes increased after the first post-operative day. Pre-operative episodes of hypoxemia significantly increased the risk of post-operative hypoxemic events (OR 2.4-4.4, CI 0.4-46), while pre- and post-operative opioid use, age, gender, ASA classification, type of surgery or anaesthesia were significantly related to the development of post-operative hypoxemia. CONCLUSIONS: One third of the patients suffered from increased and prolonged episodes of severe nocturnal hypoxemia during the first week after THA/TKA discharge. Increased risk for severe hypoxemic episodes was related to pre-operative hypoxemia.

Early patient-reported outcomes versus objective function after total hip and knee arthroplasty: a prospective cohort study.

AIMS: The purpose of this study was to assess early physical function after total hip or knee arthroplasty (THA/TKA), and the correlation between patient-reported outcome measures, physical performance and actual physical activity (measured by actigraphy). PATIENTS AND METHODS: A total of 80 patients aged 55 to 80 years undergoing THA or TKA for osteoarthritis were included in this prospective cohort study. The main outcome measure was change in patient reported hip or knee injury and osteoarthritis outcome score (HOOS/KOOS) from pre-operatively until post-operative day 13 (THA) or 20 (TKA). Secondary measures were correlations to objectively assessed change in physical performance (paced-walk, chair-stand, stair-climb tests) at day 14 (THA) or 21 (TKA) and actual physical activity (actigraphy) measured at day 12 and 13 (THA) or 19 and 20 (TKA). RESULTS: Patients reported improved physical function (HOOS or KOOS) pre-operatively until day 13 (THA) or 20 (TKA) with a mean difference of 7 (95% confidence interval (CI) 1 to 13, p = 0.033) and 6 (95% CI 1 to 12, p = 0.033) percentage points, respectively. By contrast, objectively assessed physical function and activity declined, with no correlations between subjective and objective assessments for either THA or TKA patients (r2 ≤ 0.16, p ≥ 0.314). CONCLUSIONS: Early improvement in patient-reported physical function after THA/TKA does not correlate with objectively assessed function, and patient reported outcomes should not be used as the only measure of recovery. Cite this article: Bone Joint J 2017;99-B:1167-75.