The direct anterior approach for total hip arthroplasty has shown to improve multiple early outcome measures. However, criticisms suggest improved results may be due to selection bias and protocol changes. This study compares mini-incision posterior approach to direct anterior approach performed by one surgeon, controlling for influences other than the surgical approach itself. An IRB approved retrospective review was conducted on 150 consecutive primary total hip arthroplasty patients; the first 50 from mini-incision posterior approach, followed by 50 during the learning curve for direct anterior approach, and 50 subsequent cases when the approach was routine. Peri-operative protocols were alike for all groups. Data collection included patient demographics, anesthesia, operative times, discharge disposition, length of stay, VAS pain scores, progression from assistive devices, and narcotic use at follow-up of two and six weeks. Statistical methods included Wilcoxon rank sum, ANOVA, Kruskal-Wallis, chi-square, fisher exact and t-tests. P-value of <.05 was considered significant.Introduction:
Methods:
Compartment syndrome (CS) is a unique form of skeletal muscle ischaemia. N-acetyl cysteine (NAC) is an anti-oxidant in clinical use, with beneficial microcirculatory effects. Sprague-Dawley rats (n=6/group) were randomised into Control, CS and CS pre-treated with NAC (0.5g/kg i.p. 1 hr prior to induction) groups. In a post-treatment group NAC was administered upon muscle decompression. Cremasteric muscle was placed in a pressure chamber in which pressure was maintained at diastolic minus 10 mm Hg for 3 hours inducing CS, muscle was then returned to the abdominal cavity. At 24 hours and 7 days post-CS contractile function was assessed by electrical stimulation. Myeloperoxidase (MPO) activity was assessed at 24-hours. CS injury reduced twitch (50.4±7.7 vs 108.5±11.5, p<0.001; 28.1±5.5 vs. 154.7±14.1, p<0.01) and tetanic contraction (225.7±21.6 vs 455.3±23.3, p<0.001; 59.7±12.1 vs 362.9±37.2, p<0.01) compared with control at 24 hrs and 7 days respectively. NAC pre-treatment reduced CS injury at 24 hours, preserving twitch (134.3±10.4, p<0.01 vs CS) and tetanic (408.3±34.3, p<0.01 vs CS) contraction. NAC administration reduced neutrophil infiltration (MPO) at 24 hours (24.6±5.4 vs 24.6±5.4, p<0.01). NAC protection was maintained at 7 days, preserving twitch (118.2±22.9 vs 28.1±5.5, p<0.01) and tetanic contraction (256.3±37 vs 59.7±12.1, p<0.01). Administration of NAC at decompression also preserved muscle twitch (402.4±52; p<0.01 versus CS) and tetanic (402.4±52; p<0.01 versus CS) contraction, reducing neutrophil infiltration (24.6±5.4 units/g; p<0.01). These data demonstrate NAC provided effective protection to skeletal muscle from CS induced injury when given as a pre- or post-decompression treatment.
