Knee Osteoarthritis

Overview

Osteoarthritis of the knee is a very common condition that affects over 10% of the adult population. It typically starts as a gradual onset of knee discomfort and pain when weight bearing. It can progress to a more constant background pain, present at rest and at night, occasionally interfering with sleep. The background pain is typically aggravated by activity and ultimately can start to interfere with routine activities of daily living and quality of life.

Management options include Non-Surgical and Surgical treatments. Ideally the Non-Surgical treatments should be exhausted, before Surgical treatments become necessary.

Non-Surgical Treatments

Activity Modification – Essentially there is no role for rest! – This means avoiding activities that aggravate your pain, however enjoy as many activities as your knee will allow. Cycling, swimming and using a cross trainer are comfortable ways to exercise. Try not to let your knee pain interfere with your normal daily activities and your exercise routine.

Physiotherapy – It is important to attend a chartered physiotherapist for leg muscle strengthening exercises and balance/gait re-education. These can make a huge difference to the pain of osteoarthritis. Your local chartered physiotherapist is a vital part of your treatment.

Weight Loss – this is a vital part of managing your arthritis. The less weight your knee has to bear the less symptomatic and less painful your knee will be! Your knee takes six times your body weight when you ascend a step, so every extra Kg is multiplied by six. Also fat cells secrete chemicals that exaggerate your pain levels. Weight loss is really critical.

Education – Patients who understand their condition, have been shown to manage their knee arthritis better. Please read all about it, as education helps. Useful websites include my website iankellyortho.ie and www.myknee.ie.

Supports – Heel wedges, knee sleeves and more rigid “off-loading” braces can be indicated occasionally to help re-align the knee and reduce pain levels. Simple neoprene knee sleeves are available in most chemists and are certainly well worth trying.

Glucosamine – This is an “over the counter” medication that may give some symptomatic relief, although the evidence in the literature is weak. This can be in tablet form or sachet form. Talk to your pharmacist regarding allergies and potential interactions with your current medications.

Pain Killers – I suggest you start with regular application of an anti-inflammatory gel (e.g. Etoflam or Difene gel) before trying tablets. If the gel is not sufficient you should add oral painkillers. Should tablets become necessary take them on an “as required basis”, increasing to a “regular basis” with increasing pain levels. Paracetamol should be tried first, followed by an anti-inflammatory and on occasions, both are required. If the pain progresses, a stronger painkiller may be necessary, but your GP will guide you. It is important to optimize your painkillers, under the guidance of your GP.

Surgical Treatments

Injections

Steroid Injections – There is evidence in the literature that steroid injections can ease pain, however knee surgery should be deferred for a period of time following a steroid injection.
Hyaluronic Acid – there is evidence in the literature to support Hyaluronic Acid injections.
Steroid and Hyaluronic Acid combination injection.

The literature currently suggests waiting for 3 months after a knee joint steroid injection, before proceeding with knee replacement surgery, to limit the infection risk (Bhattacharjee et al, JAAOS, 2021. Albanese et al, Journal of Arthroplasty, 2023).

Knee Arthroscopy & Washout

This is a “keyhole” operation, to wash out the knee. The result of a washout is unpredictable. This procedure is not recommended if you have “bone rubbing on bone”.

See video on knee arthroscopy

Partial Knee Replacement Surgery

End stage knee Osteoarthritis is a painful condition that can be managed non-surgically. Surgery is only considered when the non-surgical treatments have failed and your knee pain is affecting your quality of life. Knee replacement surgery is really a ‘resurfacing’ operation rather than a ‘replacement’ operation, where the worn surfaces of the bones are re-surfaced with metal coatings and a durable plastic (polyethylene) is inserted between the two metal surfaces. This eliminates the painful bone rubbing on bone and should ease your pain.

We consider the knee joint to have three compartments, an inner or medial compartment, an outer or lateral compartment and a compartment on the front of the knee (the anterior compartment).

Knee OA typically involves all three compartments at the same time and we call this tricompartmental (global) OA. The surgical treatment for tricompartmental OA is a TOTAL Knee Replacement, where all three compartments are resurfaced. However, in 30% of patients, knee arthritis can be isolated to one compartment which is typically the inner or medial compartment. Hence the evolution of PARTIAL (as opposed to Total) Knee Replacement, which is designed to resurface the affected compartment only, while preserving the two remaining healthy compartments.

See video on partial knee replacement surgery

Complications of PARTIAL Knee Replacement Surgery

Infection in 0.5% of patients, necessitating antibiotics and further surgery.
Leg Clots in 1% of patients which can travel to the lung in 0.8% of patients. We give you Aspirin for 4 weeks and encourage early mobilisation to reduce this risk.
Medical complications can arise in 3% of patients (e.g. cardiac issues).
Loosening of the implant (2% risk)
Unexplained pain (1.2% risk)
Progression of your Arthritis into the two remaining compartments of the knee needing conversion to Total Knee Replacement (0.7% risk).
Dislocation of the plastic spacer (0.7% risk).
It is important to use 2 crutches for 6 weeks after your surgery, to avoid a fracture (broken bone, 0.4% risk) and to allow your bone to grow onto the implant
Stiffness can arise so pre and post-op physiotherapy are really important (0.1% risk).
Skin Numbness on the outer side of the wound is normal.

I advise patients that it can take up to 2 years to get over their operation fully, but that they should notice gradual improvements as each month progresses.

Please note – it is possible that we plan a Partial Knee Replacement, but during the operation convert to a Total Knee, because of more extensive arthritis than expected.

Total Knee Replacement Surgery

Knee Replacement is only indicated when your knee pain is affecting your quality of life, despite trying all of the non-surgical options.

Knee replacement is essentially resurfacing the knee joint to remove the painful rubbing of ‘bone on bone’. Knee Replacement surgery is generally successful, with 85% of patients satisfied with their outcome after one year. However the international literature shows that at least 15% of patients can be dissatisfied, so one must take the decision carefully, as complications can arise. It is vital to set realistic expectations of how your knee will function following surgery, as a ‘surgical knee’ is not a ‘natural knee’.

The main aim of knee replacement surgery is the reduction of pain. Pain reduction can be both gradual and incomplete. Additional aims are to return to moderate levels of activity, however your new surgical knee will not function the same as your native knee.

See video on knee replacement surgery

Complications of Total Knee Replacement

Knee Replacement surgery has a major complication rate of 6% and a minor complication rate of up to 10%.

Infection can occur in 1% of patients, which would necessitate antibiotics and further surgery. The literature currently suggests waiting for 3 months after a knee joint steroid injection, before proceeding with knee replacement surgery, to limit the infection risk (Bhattacharjee et al, JAAOS, 2021. Albanese et al, Journal of Arthroplasty).
Clots can develop in the leg in 1.3% of patients and can travel to your lung in 0.8% of patients (a pulmonary embolus). We give you Aspirin for 4 weeks after the surgery and get you moving your legs and walking as soon as possible to reduce this risk.
Instability some patients may experience instability symptoms requiring further surgery.
Medical complications can arise in 1% of patients, with more minor medical issues (e.g. urinary tract infections, delayed wound healing) in 2% of patients.
Medically Unexplained Pain can occur in 2% despite the wound and x-rays looking normal.
Stiffness An exaggerated healing response can result in excessive scar tissue formation, leading to knee stiffness following the surgery. This is seen in 4% of patients who need a manipulation of the knee under anaesthetic to improve their range of motion. Rarely (0.8%) the knee may need to be revised for knee stiffness. The best predictor of post-operative range of motion, is your pre-operative range, so working with a physiotherapist before surgery can be very useful.
Skin Numbness on the outer side of the wound is normal.
Noise most patients will notice an occasional knocking noise, which is not anything to worry about.

Please note that Obesity and Inflammatory Arthritis (Rheumatoid Arthritis or Psoriatic Arthritis) increase the risk of developing complications, in particular the infection risk is significantly increased. Weight loss is an essential part of treating knee osteoarthritis.

I advise patients that it can take up to 2 years to get over their operation fully, but that they should find gradual improvements as each month progresses.

Surgery – What to expect?

Before Surgery

Joint School:

This is a free educational programme run by UPMC/Whitfield, aimed at preoperative education and answering any and all the questions you may have. Please call Jo Breheny at (051) 319845. Patient satisfaction rates improve, when patients understand more about their surgery and have set realistic expectations. I also recommend exploring Educational Websites, including iankellyortho.ie and looking at my YouTube Video which is available on my website.

Pre-Assessment Unit:

All patients need to attend the pre-assessment unit prior to their surgery, for routine pre-operative blood workup and risk assessment.

Pre-Habilitation:

All patients should have “pre-habilitation” prior to their knee replacement – this means attending a chartered physiotherapist to start a leg muscle strengthening programme. We will ask you to re-attend this same physiotherapist after discharge to continue your rehab programme. Patients tend to have a better outcome when being advised by a physiotherapist, with a customized and appropriate exercise plan.

Showering:

Prior to admission, I recommend you shower twice a day for three days, cleaning the skin about your knee gently with normal soap. We also advise a shower when admitted to Whitfield Clinic.

Hospital Stay

Patients are usually admitted on the morning of their surgery and you can be discharged once your pain is under control and your knee is moving well. Before theatre, you will be fasting, so we will give you a sugar drink. You will also receive some pain-killers (pre-emptive analgesia) before coming to theatre. Don’t worry – you will not hear any noise in theatre!

You will start walking the next day, using 2 crutches, with the assistance of our physiotherapist. Please bring loose comfortable clothes to wear about the ward, with appropriate safe footwear (no loose slippers!)

Upon Discharge

You can be discharged once your pain is controlled and you have reached your physiotherapy targets including good knee motion, safe and confident on crutches and able to negotiate stairs. You will be given a prescription for pain relief and Aspirin and advised to attend your local physiotherapist for further rehab and we will see you 10-12 days after the surgery for wound inspection. Once your wound is healed, you can exercise in a pool or on a stationary bicycle.

Everyone is sore initially after a knee replacement, but the pain is manageable with routine painkillers and regular icing and Physicool. You will have two crutches, but you can gradually dispense with these as you feel comfortable and safe. It is okay to fully weight bear as tolerated through your knee once you feel able.

I see you again at 10-12 days for wound inspection, 6 weeks for a review (with new radiographs) and 12 weeks to be seen our Outcomes and Research Unit. I suggest it is best to have someone at home with you for the first two weeks and I do not recommend driving until you are off both crutches.

What to expect following your knee replacement surgery

Pain relief following knee replacement surgery can be gradual, variable and incomplete. Some patients report ongoing discomfort for 2 years. Occasionally an anti-inflammatory gel is necessary. Most patients notice a ‘knocking’ sound from their new knee, which is entirely normal and to be expected. Numbness over the incision site and difficulty with kneeling and stair climbing can persist for 2 years, but we encourage you to use and push your new knee as much as you feel able.