Is a labral repair required in association with Periacetabular Osteotomy (PAO)?

It is not unusual to be asked if a labral tear needs to be repaired when this is found in association with dysplasia and a PAO is being planned.
The development of pain in hips with dysplasia is usually as a result of an injury to the labrum. The labrum is a soft cartilaginous tissue that attaches around the edge of the hip socket (the acetabulum) and provides a suction seal for the joint. It has lots of nerve endings in it which means that when it is injured pain is experienced. The injury that usually occurs to the labrum can happen in a number of ways, but the most common injury is a separation that occurs on the deep side of the labrum (the joint side) which maybe enough to create pain. The important point about these injuries is that the main structural part of the labrum that anchors it to the bone of the acetabulum, remains intact in the vast majority of cases. It would be extremely unusual for there to be a complete detachment of the labrum.

In the context of dysplasia, the shallow acetabulum results in there being abnormally high stresses on the margins of the acetabulum and over time with these repeated higher than normal loads the labrum starts to be injured and the hip starts to become painful. One of the features of the labrum in more severe cases of dysplasia is that it is often larger and thicker than normal as it adapts to try and resist the high loads being transmitted to the edge of the acetabulum and so provides improved stability.

The reason that pain gets better after a PAO is that the labrum is no longer having to resist the abnormally high load and the stress is taken off the labrum so the injured area no longer transmits pain.
The longterm outcomes of studies on PAO surgery for dysplasia, which have shown good success, did not have routine repair of the labrum as part of the procedure. More recently there have been trends towards repairs of the labrum, mostly in North America. Recent articles reviewing the outcomes of studies which have combined labral repair with PAO surgery have not found that there is a specific benefit in outcome when compared with cases in which the labrum was not repaired.

For the time being it would seem that the added surgical procedure to repair the labrum (by hip arthroscopy) does not confer an advantage. There are instances where this added intervention is helpful, in particular where there is an impingement issue in the hip which needs to be addressed. Hip arthroscopy is performed in a proportion of patients, approximately 10-15%, after PAO surgery usually for persistent pain from the hip and where the labral injury maybe responsible but routine repair as part of the procedure would seem not warranted.