Instability in primary total hip arthroplasty with the direct lateral approach.

Instability after a total hip arthroplasty is a serious complication. Dislocation rates as much as 6.5% after posterior approaches have been reported within the past decade. For this reason, the authors use the direct lateral approach for primary and revision total hip arthroplasties. A review of the arthroplasty database yielded 1515 primary total hip arthroplasties done via a direct lateral approach in 1333 patients. These arthroplasties were done within a 10-year period and patients with followup data less than 12 months were excluded. At the most recent examination, 11.6% of the patients had a moderate or severe limp and 2.5% had severe heterotopic ossification. Only six hips (0.4%) had a dislocation or episode of instability. Three patients had more than one dislocation and required revision surgery. The results of the current study show that dislocation after primary total hip arthroplasty almost can be eliminated using the direct lateral approach. The associated risks of heterotopic ossification or limp are acceptable.