As a surgeon who does both anterior and posterior hip replacement surgery I get asked every week which approach is better. The answer is not as simple as you might think. Both approaches have risks and benefits and each hip is different.
They key benefit of the anterior approach is that it does not involve cutting any muscle, while the posterior approach does require a small amount of muscle to be cut and repaired. In theory this could result in faster recovery and less risk of instability and dislocation. A recent meta-analysis reviewing 17 high quality scientific studies (2302 hips) gives qualified support to this. There was a slight reduction in length of stay in hospital and dislocations using the anterior approach but they also found no clear superiority of either approach.
The potential problem with the anterior approach is that it is technically challenging and exposure of the femur (thigh bone) is more difficult compared to the posterior approach. This can result in component malposition or a fracture of the femur which is harder to recognise and deal with than when using other approaches. A large study by the Adelaide based Australian Orthopaedic Association National Joint Replacement Registry looked at 5499 hips done by 68 surgeons and found that there is a learning curve with the anterior approach during which the rate of revision surgery is higher.
There are some hips for which the anterior approach is riskier than others, mainly due to the risk of fracture. There are particular anatomical variations of the hip bones that make exposure more difficult, as does obesity, and fracture is also more likely with older patients or those with osteoporosis.
It’s also important to recognise that all hip replacement approaches have become less invasive over the years. The long incision and prolonged hospital stay of previous decades have given way to smaller incisions and rapid mobilisation for all patients regardless of the approach.
My view is that the anterior approach is slightly better but only if the hip is suitable. The approach is technically challenging and should only be performed by an experienced hip replacement surgeon who is trained in the procedure. The benefits of the anterior approach are not so great that we should risk a fracture in unsuitable hips. I assess each hip on its merits and discuss the options with every patient.
More information on hip replacement surgery is available here.