Total hip arthroplasty for osteoarthritis

This summary of a Cochrane review presents what we know from research about the effects of a posterior or lateral approach in total hip replacement surgery for osteoarthritis. The review shows that:

In people with osteoarthritis of the hip, there is not enough evidence to be certain about whether the posterior (back) or the lateral (side) approach to total hip replacement surgery is better.

What is osteoarthritis of the hip and what types of total hip replacement surgery are there?
Osteoarthritis (OA) is the most common form of arthritis that can affect the hips. In some people, the damage and pain in the hip may be severe enough for surgery. In these people, the whole hip joint can be replaced by an artificial joint with total hip replacement surgery.

In total hip replacement surgery, the surgeon can make the cut from the posterior (back) or lateral (side) of the hip. Some surgeons believe that the posterior approach is better because people may have less problems walking after surgery. Other surgeons believe that the lateral approach is better because people may have less chance of nerve damage and less chance of dislocating their hip after surgery. Dislocating a hip causes pain and people may need to go to hospital to put the hip back in place.

What are the results of this review?
People in the studies had total hip replacement surgery that was either done from the posterior (back of the hip) or from the lateral (side of the hip).

Benefits of posterior and lateral approach
In people who had total hip replacement surgery:

the posterior approach may improve range of motion more than the lateral approach
the posterior and lateral approaches may improve function about the same

But there is not enough evidence to be certain about these benefits.

Harms of posterior and lateral approach
In people who had total hip replacement surgery:

the chance of dislocating the hip after surgery may be about the same with either the posterior or lateral approach
the chance of having difficulty walking may be about the same with either the posterior or lateral approach
the posterior approach may cause less nerve damage than the lateral approach

But there is not enough evidence to be certain about these harms.

Authors' conclusions: 

The quality and quantity of information extracted from the trials performed to date are insufficient to make any firm conclusion on the optimum choice of surgical approach in adult patients undergoing primary THA for OA.

Read the full abstract...

Osteoarthritis (OA) of the hip is a progressive condition that has no cure and often requires a total hip arthroplasty (THA). The principal methods for THA are the posterior and direct lateral approaches. The posterior approach is considered to be easy to perform, however, increased rates of dislocation have been reported. The direct lateral approach facilitates cup positioning which may decrease rates of hip dislocation and diminishes the risk of injury to the sciatic nerve. However, there is an increased risk of limp. Dislocation of a hip prosthesis is a clinically important complication after THA, in terms of morbidity implications and costs.


To determine the risks of prosthesis dislocation, postoperative Trendelenburg gait and sciatic nerve palsy after a posterior approach, compared to a direct lateral approach, for adult patients undergoing THA for primary OA and to update the previous review made in 2003.

Search strategy: 

MEDLINE, EMBASE, CINAHL and Cochrane databases were searched and updated, from the previous search of 2002, to Oct 13, 2005. No language restrictions were applied.

Selection criteria: 

Published trials comparing posterior and direct lateral surgical approaches to THA in participants 18 years and older with a diagnosis of primary hip OA.

Data collection and analysis: 

Retrieved articles were assessed independently by the two reviewers for their methodological quality.

Main results: 

Four prospective cohort studies involving 241 participants met the inclusion criteria. The primary outcome, dislocation, was reported in two studies. No significant difference between posterior and direct lateral surgical approach was found [1/77 (1.3%) versus 3/72 (4.2%); relative risk (RR) 0.35; 95% confidence intervals (CI) 0.04 to 3.22]. The presence of postoperative Trendelenburg gait was not significantly different between these surgical approaches. The risk of nerve palsy or injury (all nerves taken together) was significantly higher among the direct lateral approaches [1/43 (2%) versus 10/49 (20%); RR 0.16, 95% CI 0.03 to 0.83]. However, there were no significant differences when comparing this risk nerve by nerve for both approaches, in particular for the sciatic nerve. Of the other outcomes considered only the average range of internal rotation in extension of the hip was significantly higher (weighted mean difference 16 degrees, 95% CI 8 to 23) in the posterior approach group (mean 35°, standard deviation 13°) compared to the direct lateral approach (mean 19°, standard deviation 13°).