INFORMATION AND PROTOCOLS
Significant advances in total knee resurfacing (TKR) have meant that this is a much more reliable and satisfactory operation than ten or fifteen years previously. The success of total knee resurfacing has allowed surgeons and engineers to develop the concept of partial knee resurfacing to deal with patients developing the early changes of osteo-arthritis in isolated areas of the knee. These patients have a very much higher activity profile than those with total knee arthritis.
INDICATIONS FOR PARTIAL KNEE JOINT RESURFACING
In an age of increasing patient activity and sporting interests through middle life, and with the development of more sophisticated ways of analysising knee joint deterioration, it has been possible to identify patients who are experiencing early wear in specific parts of their knee joint. In the past these patients might have been advised to give up their sport or reduce their activity until a time where the wear had spread throughout the whole of their joint and their mobility and activity decreased entirely. They then were offered a total knee joint replacement. Nowadays advancing design has made it possible to resurface these isolated parts rather than wait for the entire joint to deteriorate and the patient’s mobility to decrease. The object is to keep the patient mobile and active, whilst resurfacing only the damaged area of the joint in a much smaller and reduced operation. There are many advantages in undergoing a smaller procedure with more rapid rehabilitation and greater activity at an earlier stage following operation.
MEDIAL (INNER) KNEE JOINT WEAR
Approximately 80% of knee patients will begin to wear on the inner aspect of their joint, prior to the rest of the joint being involved. Patients present with pain on the inner aspect of the joint related to activity or movement which is easy to pinpoint and becomes more troublesome and tiresome related to activity, but then later even more minor activities cause discomfort and sleep may be disturbed.
The articular cartilage or lining cartilage of this aspect of the joint becomes worn down and the bone of the femur and tibia begin to grind together to cause pain and discomfort. At this early stage it is possible to resurface just the inner aspect of the femur and tibia with a very thin lining of a special medical grade of stainless steel which is implanted on top of the bony surfaces. To prevent the two metal surfaces grinding together a small plastic bearing is inserted on to the top of the tibial plate to allow easy articulation.
The advantages of this procedure is that none of the ligaments around the knee or indeed inside the knee are disturbed by this procedure which is simply a recoating or relining of the worn areas of the joint. This bearing replicates the role of the cartilage in the natural knee.
The prosthesis used for this resurfacing procedure is the SIGMA high performance resurfacing prosthesis (see Links section) made by DePuy, a Johnson & Johnson Company. This prosthesis has been recently developed purposefully for the more active patient and also has a number of features which allows it to be revised or added to as various other parts of the joint may wear out in the future in an active patient.
LATERAL (OUTER JOINT) RESURFACING
The mechanism of wear which causes eventually the bones to grind together on the outside aspect of the joint is very similar to that described for the medial or inner joint wear process. The minority of patients (20%) wear their knee initially on the outer aspect and this may reflect a degree of malangulation which may have been present since youth.
Nevertheless, the bone grinding on bone produces very similar pain and discomfort to that on the inner aspect of the joint and if the rest of the knee remains intact, lateral (outer joint) resurfacing is a very similar procedure to that of inner or more medial resurfacing.
Those looking for information in different sources and different websites may find that surgeons will state that resurfacing may only be performed on the medial or inner side and that lateral or outer resurfacing is not advised.
This does represent a historical standpoint and in the past outer joint resurfacing was discouraged as the results were disappointing.
There are some implants that are only designed for inner joint resurfacing such as the Oxford component. Redesign and more advanced techniques however have allowed a new concept which is equally implantable on the inner or outer aspect of the knee, this being the SIGMA high performance resurfacing prosthesis.
PATELLOFEMORAL (KNEECAP) RESURFACING
Isolated patellofemoral resurfacing is a procedure in which only the worn out and bare bone surface of the under surface of the kneecap or patella and the front surface of the femur (trochlear) are resurfaced with a metal prosthesis for the trochlear and a polyethylene or plastic surface cemented onto the patella. The attraction here of course is that if only the patella or kneecap is worn the patient may keep the rest of the natural or native knee without operation whilst a much more reduced procedure is performed to resurface the patellofemoral joint.
The procedure is much more minimal than that undertaken with total knee replacement and the patients are up and mobile often three times more quickly than with a larger procedure.
In the long term there is the possibility that further activity may cause wear and tear in the main joint of the knee but such is the patellofemoral joint employed, it is possible to resurface any extra areas of wear and tear when those occur rather than employing a total knee joint replacement at that time.
MULTI COMPARTMENTAL RESURFACING
Occasionally it is found that patients have worn in two of the three areas of the knee but because of their age and activity, total knee joint replacement is not desirable. In those isolated cases a very new and developing field of surgery is to resurface two out of three of these areas such as the patellofemoral and inner aspect of the knee or indeed the outer aspect of the knee and the patellofemoral joint, which allows the knee to keep its natural cruciate ligaments and the majority of the ligaments around the joint. This is a new and specialised procedure and may only be undertaken in patients who are particularly suitable for the operation.
The advantages however mirror those of partial resurfacing with more activity being possible in the post surgery period and much more rapid recovery.
You will be called to the hospital prior to your operation for assessment of your physical health. This ensures that you are fit and medically well to undergo surgery and there will be no problems with the administration of anaesthetic or other treatments. Samples of blood and urine are taken and the heart and lungs are assessed and checked to ensure all is well. Please ensure that any X-rays taken of the knee or chest are brought with you to the hospital on the day of surgery. These are essential for the planning and execution of the joint replacement.
You will also see a physiotherapist who will assess your knee and gait and tell you what to expect post surgery. You will be given a booklet about your knee operation. Please bring it back in to the hospital with you.
On the day of operation you will be seen by myself and my anaesthetist prior to surgery. The operation to resurface the knee may normally take one and a half hours, although more time may be required if the operation is difficult or complex.
The incision is made obliquely on the inner aspect of the joint to allow access to the knee without damage to the ligaments or at the patella or kneecap. The advantages of a minimal approach allows more rapid mobilisation and avoids disturbing the sensitive connective tissues around the joint.
Following surgery, you will be returned to the ward and will note that there will be a dressing on the knee consisting of a elasticated bandage. During the procedure your knee will be infused with local anaesthetic to avoid discomfort on waking and to control any discomfort in the post-operative period. There will be some discomfort after the operation and painkilling drugs are given during the procedure. If you do have discomfort, however, please alert a member of the nursing staff as all patients are prescribed painkilling drugs which should be used to reduce discomfort. Pain control is vital to ensure you are able to co-operate with physiotherapy over the few days of your hospital stay.
If you are well enough, you will see a physiotherapist in the afternoon to begin your exercises and gait training.
On the morning following surgery blood samples will be taken to ensure all is well following the operation. X-rays are taken to ensure that the knee prosthesis is correctly and accurately situated. These will be shown to you during your hospital stay. The physiotherapists will encourage weight bearing and walking. Some patients will have also achieved stair climbing by the end of the day.
During the subsequent stay on the ward the aim is to achieve full straightening of the knee, the ability to bend the knee to a right angle (90º) and to promote wound healing and reduction of swelling and discomfort.
The physiotherapist will visit regularly to encourage muscle exercises to allow the knee to be moved more fully and strengthen the muscles.
You may fully weight bear through the knee and initially the physiotherapist will supervise you in the use of crutches and walking exercises. Movement out of bed is encouraged and progressively the physio will increase the bending angle of the knee during this period. Initially mobilisation will take place on crutches with the supervision for trips around the room and for toilet visits, but subsequently these walks will become longer down the corridor and before discharge all patients will be confident and safe in ascending and descending stairs. The physiotherapist will instruct and help you in achieving muscular co-ordination and strengthening of the knee during this period. Active participation is required for this and thus the pain and discomfort you may have must be controlled with painkillers to allow you to help the physiotherapist get the knee moving again.
Recovery from partial knee resurfacing is said to be a little more rapid than standard knee surgery.
Initially, the knee will be a little stiff and I would encourage you to actively bend and straighten the knee gradually increasing your activity and walking distance in the first few weeks following surgery. The physiotherapist will continue her treatment in out patients and will be offering further advice and exercises to allow you to improve the function of the joint. These physiotherapy visits will be arranged prior to your discharge from hospital if subsequent physiotherapy is required.
A follow-up appointment with myself will take place approximately 6 weeks following surgery and by this time most patients are feeling a little more confident and have improved their walking distance and stability. Rates of individual progress vary however, and depending on the extent of the original arthritis some patients will proceed faster than others.
If all is well at the 6 week appointment, I then normally see patients in approximately 6 months post-surgery to ensure that a full range of movement has been achieved, that the knee is working well and normal walking has been recovered with or without a stick for stability.
Further improvement is known to occur up to a year following joint replacement.
Results from partial knee resurfacing are available on the inner aspect of the joint over the last twenty years. They lead us to anticipate that we should expect at least twelve to fifteen years good function from this area. The particular implant that I use has an exchangeable bearing made of polyethylene or plastic which may be exchanged beyond ten years post-surgery in order to improve and prolong the life of the implant. The partial knee resurfacing system that I employ also has components which will cover the outer aspect of the knee and additionally the patellofemoral (kneecap) joint. Therefore if arthritis spreads as the patient becomes older, it will be possible to add further areas of resurfacing to the existing resurfacing covering all eventualities for the future.
Patients who undergo this procedure have a higher rate of activity and achievement than those having a total knee resurfacing. It is reasonable to undertake most forms of active sport on this knee including dancing, doubles tennis, swimming, walking and most gym activity. Jogging or long distance running is not encouraged on these implants. Many patients ski and are involved in winter sports as well as sailing and other marine activities.
As with any demanding or major joint surgery, there may be complications which hopefully are of a minor nature.
Some patients occasionally suffer problems with wound healing and the scar on the outer or inner aspect of the knee which is approximately 4 ins. long (please also see elsewhere the section on wound healing) sometimes takes a little time to heal and will exhibit some bruising.
Sometimes patients suffer some problems in achieving bending of the knee and this often is related to the severity of the arthritis before surgery. Every assistance and help will be given by the physiotherapist to achieve full function of the knee.
The most serious complication is that of infection. The knee prosthesis is an artificial insert into the human body and therefore it is possible for bacteria that may arise in the bloodstream to infect the joint. This causes pain within the knee replacement and in the most serious cases requires the removal of the knee prosthesis with its subsequent replacement a few weeks later.
This serious complication occurs in less than 1% of patients in my practice and is be minimised by the use of antibiotics during the implantation procedure and the use of antibiotics subsequently if it is apparent there is any infection in the foot or knee. Any extensive dental procedures that may require intra-oral surgery should be covered by antibiotics also and your dentist should be made aware of the fact that you have a joint replacement.
Deep venous thrombosis (DVT) or the forming of clots in the veins of the knee is a recognised complication. To avoid DVT, patients’ blood is thinned during surgery and for a short period afterwards. Intermittent compression pumps on the feet maximize the circulation post-surgery in the first few days. Patients also wear compression stockings for the first few weeks post operation.
HELP AND ADVICE
Should you have any questions regarding knee surgery or be concerned regards pain or swelling in the post operative period please feel free to contact the person on any of the numbers listed below:
Nursing Staff on Nursing Unit 2 02380 775544 Ext 2372
Physiotherapy Department 02380 775544 Ext 2348
Bernice Allison, Professor Barrett’s Personal Assistant 02380 776877
Aimee Dibden, Secretary to Professor Barrett
OPERATION SITE CARE
An incision following surgery heals through several phases. These three phases are summarised in Fig. 1. The rate and speed of healing depends on many factors including the health of the patient and many variables that differ between patients as well as environmental factors and the extent of surgery.
Your incision will be healed within two weeks from surgery unless there has been some reason to delay healing. Additionally some patients have other medical problems such as diabetes or medication such as steroids that may cause additional time for their incision to completely heal. Patients who are significantly overweight or smoke may also find the rate the incision heals is slowed in these cases. A healthy balanced diet is important in healing of the incision. If you have questions about the time it will take for your incision to heal discuss this with your surgical team (see contact information).
Most surgical incisions will heal without problem. However, wound infections (this means that germs have started to grow in the wound) is a serious complication following knee surgery, so patients are given antibiotics by vein at the time of surgery – which reduces the risk to less than one percent. Following this, two further doses of antibiotics are necessary. Patients are responsible for the care of their incision and prevention of infection. Good personal hygiene and proper wound care are of utmost importance.
Professor Barrett and his surgical team will do everything to reduce chances of your incision becoming infected whilst you are in hospital. Your surgical incision will be assessed each day to ensure that it is progressing and there is no sign of infection present. They will alert you to any concerns you have about your incision and specific instruction regarding your incision and care.
HOW DO I TAKE CARE OF MY OPERATION SITE AT HOME?
Operation site care does not just start and finish in a hospital as there are many things patients can do at home to help prevent an infection getting onto their incision. It is not uncommon for patients to go home with their stitches or clips still in situ which may need removing at a later date. Stitches/clips and scars can become itchy as the incision heals and it can be very tempting to scratch the itch but this should be avoided at all costs. Not only might it introduce bacteria to the incision but it may affect how the scar heals and how the stitches are holding the incision together. Patients who do experience itching must not give into the urge and resist it until the doctor or nurse removes them or they have completely dissolved.
Surgical dressings are used to prevent bacteria which exist on our skin and in the atmosphere and in all of our homes, from being able to settle on the incision site and grow in the vulnerable tissues. The dressings are very important to ensure that this growth in the incision does not occur and patients may play their part by not tampering with the dressings until the incision is fully healed and they have been told either by the district nurse or ward staff that it is safe to change their own dressings. It can be very tempting to take a little look at your surgical incision site following surgery but this increases the chances of developing an infection and should be avoided at all costs.
The purpose of the dressing is to:
• absorb any leakage from the wound
• provide ideal conditions for healing
• protect the area until the incision is healed
• prevent stitches or clips catching on clothing
Changing the dressing
The original dressing can be left in place for two days following discharge from the hospital. The dressing should be dry and not soaked with blood or any other liquid. After the initial two day period you may change the dressing every two or three days until your stitches or clips are removed.
Before you remove the dressing, you must wash your hands with gentle soap and warm water and then carefully take the dressing off. Don’t touch the healing incision with your fingers.
The healing incision can then be covered with a fresh dressing. Most people like to continue wearing a dressing over the area for protection, especially if clothing is going to rub against it.
The hospital will supply a replacement dressing for you to use at home. Apply the dressing carefully and don’t touch the inside of the dressing. There is no need to use antiseptic cream under the dressing.
WHEN CAN I TAKE A SHOWER?
In most cases this will be approximately 2 days after your clips/stitches are removed. Normally prolonged bath, bathing or soaking in water is discouraged for the first two days after clip removal to avoid soaking the operation site in bath water. If bathing is preferred to showering, a brief and swift bath is much preferable for satisfactory incision care
Before the stitches/clips being removed you may bathe the leg using a clean flannel with warm water and gentle soap morning and evening, avoiding the dressing which remains in place. The limb should be gently dried by patting with a clean towel to absorb moisture.
Some general points to note are outlined below:
• Showering is preferable to bathing.
• DO NOT REMOVE any dressing before having a bath or shower. The dressing provided to you will be a waterproof dressing therefore can be left in place.
• Don’t use any harsh soap, shower gel, body lotion, talcum powder or other bathing products directly over the healing wound.
• It is permissible to allow the shower water to gently splash onto the dressing/healing incision. However don’t rub the area, as this will cause pain and might delay the healing process.
• Only have a bath if the healing incision can be kept out of the water. Don’t soak the area as this might soften the scar tissue and re-open the wound.
• Dry the healing area carefully by patting it gently with a clean towel.
IF YOU HAVE CONCERNS ABOUT YOUR INCISION SITE
It is important that you know how to tell if you are developing an infection after you go home. If an incision becomes infected, it may:
• become more painful
• look red, inflamed or swollen
• leak or weep liquid, pus or blood
• smell unpleasant
If you are concerned about your incision or if you develop a high temperature, or notice any of the signs listed above, you should contact the hospital. Infections can be treated successfully if they are diagnosed early.