Leg Length Difference Following Total Hip Replacement

Some patients feel that their leg is longer following a hip replacement. This may be because the leg is actually longer, or in some cases because it feels longer even though the leg lengths are the same. This is called an apparent leg length difference.

In arthritic joints, bone and cartilage degeneration occurs over an extended period of time. The resulting decrease in joint space and soft feel of the joint is not noticed as changes occur slowly and the body adapts. When an artificial joint is inserted, the whole are feels different resulting in a feeling that the leg is longer even though the legs length is the same. Patients too are generally aware of every sensation around the hip, as it is understandably the main area of their focus following their surgery. Prior to surgery, gait, movement and mobility are all affected by the worn hip, with the hip, knee, foot and low back having to adjust to help assist with the disability. With resulting soft tissue contracture and postural changes, these need time to adjust following surgery to allow transition back towards the original mechanics required for day-to-day living.

After surgery the operated leg is occasionally longer than the non-affected leg. In the majority of these cases, the length difference is less than 1cm and generally has little impact on patients, as resulting soft tissue irritation is minimal.

In about 20% of cases, the operated leg is lengthened greater than 1cm. Sometimes this is because the surgeon deliberately lengthens the leg to correct a difference prior to surgery, or because a larger prosthesis is used to stabilize the joint. This can however result in strain on the soft tissues and nerves and may result in pain, around the hip, the spine and nerve pain referred down the leg.

Leg length may be adjusted in the longer term with a shoe or heel lift, however gentle stretching of the soft tissues and nerves surrounding the hip will often need to be completed.