Introduction Smaller skin incisions during a minimally invasive approach to total hip arthroplasty may accelerate rehabilitation and reduce inpatient stay. Cutaneous nerve injury from a standard 20cm lateral approach was compared with a new, oblique minimally invasive 10cm incision.

Method The two surgical approaches were defined on fifteen cadaveric thighs. Cutaneous nerves lying deep to the incisions were dissected out. Projected nerve injury resulting from each approach was recorded.

Results The mean number of nerves divided by a standard approach was 5.0 compared with 4.1 in the minimally invasive approach (mean difference 0.87, 95% confidence interval 0.03 to 1.7, P=0.043). However, the mean number of nerves per cm divided by the standard approach was 0.25 compared with 0.41 by the minimally invasive (mean difference −0.163, 95% confidence interval −0.09 to −0.24, P< 0.001).

Discussion The oblique incision ran perpendicular to the underlying cutaneous nerves; therefore, more cutaneous nerves were divided per cm than a standard approach. A 10cm oblique incision divides as many nerves as a 16cm standard approach.

Introduction Infection is a disastrous complication of arthroplasty surgery, requiring multidisciplinary treatment and debilitating revision surgery. As between 80–90% of bacterial wound contaminants originate from colony forming units (CFU’s) present in operating room air tending to originate from bacteria shed by personnel present within the operating environment, any steps that can reduce this bacterial shedding should reduce the chances of wound contamination. These steps have included the use of unidirectional downward laminar airflow theatre systems, and the introduction of theatre attire modelled on this principle (e.g. total body exhaust suits). Our unit has introduced the use of the Stryker Sterishield Personal Protection System helmet in conjunction with laminar flow theatre systems. This study compares an enclosed helmet system used with standard gowns, with standard hood & mask attire.

Method 12 simulated hip arthroplasty operations were performed, six using disposable sterile impermeable gown, hood and mask, with a further 6 using a Sterishield helmet & hood. Each 20 minute operation consisted of a series of arm and head movements simulating movements performed during surgery. Air was sampled at wound level on a sterile draped operating table using a Casella slit sampler, sampling at 700l/minute. Samples were incubated on Blood agar for 48 hours at 37°c & the CFU’s grown were counted.

Results The mean number of CFU’s for the helmet was 9.33 with hood and mask attire having 49.16 CFU’s (S.Ds 6.34 & 26.17; p value 0.0126). In all cases, the organism isolated was a coagulase negative staphylococcus

Conclusion Although the sample size was small, we demonstrated a fivefold increase in the number of CFU’s shed when using hood and mask attire compared to personal helmet and sterile hood. We conclude that the helmet system is superior to non-sterile hood & mask at reducing bacterial shedding by theatre personnel.