Background:
Total Hip Arthroplasty (THA) is one of the most commonly performed and successful orthopaedic surgeries. At the same time, the issue about the best surgical approach for THA remains controversial. This systematic review aims to evaluate the current evidence for the use of Minimally-Invasive Surgery (MIS) in THA.

Methods:
A systematic literature search of PubMed, Medline and Embase was conducted. Randomised controlled trials, comparative studies, and cohort studies were included in this systematic review. Main outcome measurements included incision length, blood loss, operating time, length of stay, complications, postoperative pain on a Visual Analogue Scale (VAS), Short Form 36/12 Health Survey (SF 36/12), Harris Hip Score (HHS) and cup inclination.

Results:
A total of 30 studies met the inclusion criteria. There was no significant difference between MIS and conventional approaches for THA with regards to complication rates and implant inclination angle. The average operating time in 10/24 (41%) studies was significantly (p<0.05) longer in the MIS group. MIS THA lead to an improvement, patient-centered results with reduced blood loss in 9/16 (56%), reduced use of analgesics in 4/4 (100%) and reduced myoglobin correlated muscle trauma in 3/4 (75%) of the analysed studies. Additionally, 10/10 (100%) studies reported less postoperative pain after MIS THA, 16/19 (84%) studies detected an improved postoperative Harris Hip score and 7/7 (100%) studies an improved SF36/12 score respectively. This resulted a reduced length of stay in 10/10 (100%) of the studies when compared to THA utilizing a conventional approach.

Conclusion:
MIS in THA is nowadays no longer seen as just cosmetically attractive but rather as a real improvement for the clinical outcome. There is evidence for improved patient related outcome following MIS THA.