This is the editor's interpretation of a paper published in the orthopaedic literature in 2007 - our attempt to make relevant medical articles accessible to lay readers. If you want to read the original it is easy to ask your librarian to obtain a reprint for you from any medical library.
This paper concerns the small percentage of patients that do not do well following total knee replacement. The authors report their own experience in a group of patients where progress had not been ideal, and what efforts they made to improve the situation.
When rehabilitation seems to be failing due to continued pain or functional problems, the authors usually assess the knee as follows:
- X-ray to identify any loosening of the knee replacement prosthesis, poor positioning of the prosthesis, retained bone cement (used for cementing in the prosthesis), and infection
- If infection is suspected, knee fluid is aspirated and cultured to identify bacteria
- If the X-ray seems fine, then a careful examination is made to see if the problem relates to the soft tissues. This includes range of motion, limb length, muscle strength and gait analysis.
The paper has a nice flow chart showing what therapies were used for which problem, and you can get a reprint of the article from your library if you are interested in this. The paper also goes into detail about rehabilitation and shows photos of a number of proprietary (eg JAS Device) and home-made (using rehabilitation elastic bands including Theraband) active systems for improving range of motion. The interested reader again can access this from the original article, but here we will just go over a few other managements not so well covered on the KNEEguru site that we feel might interest you -
Botulinum Toxin Injections
Eight patients were assessed as having ridigity of the hamstring and/or gastrocnemius muscle as the primary cause of flexion contracture. They were treated with botulinum toxin type-A injected directly into the muscles at the back of the knee that were identified as having tightness and spasm. The average time from surgery to having the injections was 18 months (range 3-81 months).
Botulinum toxin ('botox') paralysis the muscle by interfering chemically with nerve transmission at the nerve endings. The effect lasts for about three months, which gives the physiotherapist a window-of-opportunity to improve range of motion with an intensive programme. There were no serious complications related to the botox - one patient had a transient flu-like illness and another local redness and swelling for a few days. Eight of the nine patients who received the injections had much improved function and even the one who did not improve as much as the others reported that things were better. The improvements lasted after the botox wore off.
In patients with an extension lag, including those who had botox injections, electrical stimulation was used in conjunction with exercise regimes during rehabilitation to help activate the quadriceps.
Manipulation under anaesthesia (MUA)
Patients with a range of motion of 90 degrees or less at six weeks after the knee replacement despite rehabilitation efforts were considered for MUA. Manipulations were not used if the prosthesis was badly positioned or was failing for some other reason. They were not used if three months had already passed after joint replacement. The authors outlined the varying results reported by other surgeons for MUA and noted that the subject needs more evaluation.
Peroneal Nerve Release
Constant burning or shooting pain of the top of the foot was experienced in the fourteen patients where the peroneal nerve had been damaged around the top of the fibula (at the outer side of the knee) during the knee replacement. Nerve conduction studies confirmed in all of them that the nerve was damaged. The authors felt that mostly this was due to direct pulling on the nerve during surgery, due to the traction implements that open the space to allow the operation. They felt some may have been due to tight compression dressings - or there may have been a combination of the two. The nerve was 'released' surgically by cutting tight tissues around it, and this led to restoration of nerve function in all of them although one failed to recover well with respect to range of motion due to a flexion contracture that was resistant to treatment.
With respect to surgery for arthrofibrosis, soft tissue release been discussed in several of the arthrofibrosis articles on the KNEEguru site and will not be repeated here - but if you are interested there are details in the article. If the prosthesis had been badly positioned and this was a major contributor to the functional problems then revision knee replacement was advocated.