Tourniquet time in total knee arthroplasty.

BACKGROUND: Whether the arterial tourniquet in total knee arthroplasty (TKA) is a friend or a foe is still debated. Longer ischemia causes hypoxic damage; yet short duration of a tourniquet may influence outcome. Understanding the time-dependent influence of the tourniquet in TKA patients could improve the overall outcome and safety. The purpose of the study was to measure the tourniquet-induced time-dependent alterations in skeletal muscle metabolism in TKA to establish a 'safe tourniquet time.' METHODS: In the femoral quadriceps muscle of 12 patients undergoing a total knee arthroplasty with a tourniquet (TKA) we measured the ischemic response using microdialysis. Lactate, pyruvate, glucose and glycerol were measured in the muscle underneath the tourniquet, in the ischemic muscle distally to the tourniquet and in the opposite muscle as a reference. RESULTS: Lactate pyruvate ratio (L/P ratio) increased time-dependently after 15min of ischemia. L/P ratio increased faster underneath the tourniquet compared to ischemic tissue distal to the tourniquet. Glycerol was elevated underneath the tourniquet compared to ischemic tissue distal to the tourniquet and correlated to the individual ischemic response. Only minor increases in creatine-kinase, asparagine-aminotransferase, and lactate-dehydrogenase were observed. Thirty minutes of reperfusion normalized lactate levels. CONCLUSIONS: The muscle underneath the tourniquet suffered more from ischemia than the ischemic tissue distal to the tourniquet. Less than 15min of ischemia did not increase ischemic markers. If any muscle damage occurs from longer tourniquet time, it is likely reversible and occurs mainly underneath the tourniquet. Fifteen minutes of ischemia appears safe.

Analgesic effect of perioperative escitalopram in high pain catastrophizing patients after total knee arthroplasty: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Sufficient pain treatment remains a challenge after total knee arthroplasty (TKA), especially in high pain catastrophizing patients. Serotonergic signaling may be involved in pain processing, but the effect of selective serotonin reuptake inhibitors on well-defined postoperative pain has not previously been investigated. The authors hypothesized that perioperative escitalopram would reduce pain after TKA in high pain catastrophizing patients. METHODS: A total of 120 pain catastrophizing patients (selected using the pain catastrophizing scale as preoperative screening tool) scheduled for TKA were randomized in a double-blind manner to either 10 mg escitalopram or placebo daily from preanesthesia to postoperative day 6 in addition to a standardized analgesic regime. The primary outcome was pain upon ambulation 24 h after surgery. Secondary outcomes were overall pain during well-defined mobilizations and at rest from 2 to 48 h and from days 2 to 6, morphine equivalents, anxiety, depression, and side effects. RESULTS: Pain upon ambulation (mean [95% CI]) 24 h after surgery in the escitalopram versus placebo group was 58 (53 to 64) versus 64 (58 to 69), the mean difference being -5 (-13 to 3), P = 0.20. Overall pain upon ambulation and at rest from days 2 to 6 was lower in the escitalopram versus placebo group, as was depression score at day 6 (all P ≤ 0.01 in analyses uncorrected for multiple tests). Side effects were nonsignificant except for reduced tendency to sweat and prolonged sleep in the escitalopram group. No other between-group differences were observed. CONCLUSIONS: Escitalopram did not reduce pain upon ambulation 24 h after TKA in high pain catastrophizing patients. Future studies on optimal timing, dose, and duration of selective serotonin reuptake inhibitor treatment might be warranted.

Up to 10-year follow-up of the Oxford medial partial knee arthroplasty--695 cases from a single institution.

Partial knee arthroplasty (PKA) has shown obvious advantages compared to total knee arthroplasty, but survival of PKA from different institutions and registries has differed. In our institution, 695 consecutive Oxford medial PKAs were performed from 2002 to 2011 with mean follow-up of 4.6 years. The overall 10.7-year survival rate was 85.3% (95% CI: 78.7%-90.0%), and no difference in survival for gender and age younger or older than 60 years was found. One year after PKA, 94.3% were very satisfied or satisfied, as were 93.6% six years postoperatively. The revision rate was 7.3% (n=51), and the most common causes for revision were progression of osteoarthritis (n=16), aseptic loosening (n=11), and pain without loosening (n=10). Only 50% of patients revised for pain without loosening had a satisfactory outcome.