Once you’ve had hip or knee surgery, you would expect that you could get back to comfortable, mobile, and hopefully pain-free living after your recovery rehab period. Unfortunately, for some people, amidst caring for their repaired leg, they actually begin developing pain in the other. While it’s frustrating and disheartening, it is something we see from time to time, given our work helping many patients with their post-surgical recovery and our work with orthopaedic surgeons.
To help, today our podiatrists have shared reasons why you may be experiencing this pain and what it means for your recovery.
Causes Of Pain In The Opposite Leg After Surgery
Finding out the exact cause of your pain is one of our main goals in your biomechanical assessment. From our experience of working with patients after procedures like total hip replacements and knee repairs (like ACL reconstructions), the pain may be a result of:
Leg length difference
Joint replacements use prosthetic joints that are designed to mirror the structure of your healthy joint as closely as possible, as this anatomy has variations from person to person – however, it might not be perfect. The end result may be a small difference in your leg length between the two legs, and this small difference can result in significant pain.
The incidence of a leg length difference after a total hip replacement has been as high as 27% according to studies, with the average difference ranging between 1mm and just under 16mm, but the range extending up to 70mm for some patients.
The rate at which the difference starts to cause a problem varies from person to person. While studies show that a 10mm difference is well tolerated by many people, we’ve seen differences as small as 8mm start to cause discomfort for our patients, with most pain starting around the 13-15mm mark and upwards.
It should be noted that even the most meticulous and careful surgical procedures may end in a leg length difference, as often the joints being replaced have sustained significant damage, so the new joint created for you will have some important differences.
Overuse and fatigue
During your recovery from surgery, it’s likely that you will have some kind of offloading or rehabilitative device on the operated leg – it could be a crutch, boot, splint, brace – with the goal of limiting or removing pressure from the leg to allow it to heal and repair. This ups the demand on your other leg, which then has to work harder for longer, while your body may be working against the weight of your boot or rehabilitative device. The result can be overuse.
Simply put, your muscles and joints are having to temporarily work harder to keep you moving, and they’re not used to this load. They fatigue faster, and keeping them working with less time to rest in between can lead to muscle strains or other injuries, ultimately resulting in pain and discomfort.
Proprioception is the ability of your body to know where a body part is at any given time. If you close your eyes and touch your nose with your finger, this is proprioception in action – knowing where your nose is and where your finger is moving to touch it. You’ll experience proprioception daily, from kicking a ball without watching the kick, to throwing a ball without watching the throwing hand.
With procedures like ACL reconstructions in the knee, proprioception can become disrupted. The ACL contains nerve fibres that work to communicate proprioceptive feedback to the body, and ACL tears can disrupt this feedback. Studies have shown that an ACL tear in one knee may impact the feedback in the other knee too, inhibiting the body’s ability to protect the other knee during regular activities, and making this opposite knee more vulnerable to pain and injury – and unfortunately a second ACL tear, too.
Antalgic gait describes an altered pattern of walking, often limping, that develops as a result of pain or discomfort. In the case of surgery, it is often a result of attempting to remove any weight and load off the operated leg, especially in times where you may remove any protective devices like moon boots that are usually worn, and are being careful to still promote your recovery.
Compared to normal and healthy gait, in antalgic gait, the ‘stance’ phase of the operated leg, where it is in contact with the ground, decreases significantly, the ‘swing’ phase increases, and your normal symmetrical and cyclic gait becomes disrupted and very different demands start being placed in the body. The result is the same as what we mentioned earlier – fatigue and overuse.
Nerve damage and muscle weakness
It’s worthwhile noting that nerve damage may occur following any surgery, and that muscle weakness may be present throughout recovery. Nerve damage can alter our sensation, our muscle control, and other factors. Hence, this can contribute to developing an antalgic gait as the uninjured leg tries to compensate, as well as developing fatigue and overuse pain.
Getting pain in the opposite leg? We can help
If you’re experiencing foot, leg, knee or hip pain, our team of experienced podiatrists are here to help. We work extensively with our community and surgeons to help optimise the post-surgical recovery of their patients, helping rehabilitate any problems that may arise including pain in the uninjured leg.
We have a wide range of innovative treatments, and now have our own orthotic mill in-house for effective solutions to problems like leg length discrepancies. Even without additional pain, we’re proud to help patients get the best results after their procedures by optimising their rehab and recovery.
Book your appointment with us by calling (02) 8405 6850 or book online here.