Healing after Hip Replacement: Comparing bone with tendons

Having recently undergone surgery to my shoulder for a rotator cuff tear, I have been able to reflect on the major differences  there are with bone healing compared to soft tissue to bone healing.

In hip replacement surgery we often use implants with a special coating on that allows bone to bond directly to the metal of the implant (so-called uncemented hip replacement). Once this bond has occurred, it is incredibly strong and is part of the reason implants can function for such a long time without becoming loose. That process of bonding takes 6 weeks to occur and during that time it is important that there is minimal movement between the implant and the bone, otherwise a strong bond does not occur. During the first six weeks after surgery, therefore, it makes sense not to over stress this implant bone interface so as not to compromise long lasting fixation. With that in mind I usually recommend patients be rather gentle with their rehabilitation exercises in the first six weeks. After that, once the bond has developed then it is fine to load the hip more and progress to higher levels of exercise activity.

Contrast that to how long things take when muscle and tendon is attached to bone as in my rotator cuff repair. It takes 3 months before there is a reasonably strong attachment and even then exercise needs to start very gently to avoid disrupting the bond. By three months many active patients with hip replacements can already be out jogging.

My message to those getting impatient with their hip replacement recovery in the first 6 weeks is to give a thought to those who are on the soft tissue healing pathway which is at least 2 to 3 times longer!