Arthroscopy of the Knee

Introduction

Knee arthroscopy is a surgical procedure used to diagnose and treat problems in the knee joint. An arthroscope is a small fibre-optic viewing instrument which has a tiny lens, light source and is connected to a video camera. The camera displays images on a television screen. The arthroscope is introduced into the knee joint through a small incision. Using this portal, fluid is introduced to expand the joint and allow vision and access. While holding the arthroscopy with its attached camera in one hand, the Surgeon is able to insert instruments through one or two other small incisions to enable repair of damaged knee. 

The advantage of the arthroscopy is that it uses small incisions and is much less traumatic to muscles, ligaments and tissue so leading to a quicker patient recovery.

Indications for knee arthroscopy

  • Repair or removal of a meniscal tear (“torn cartilage”).
  • Removal of damaged or unstable articular hyaline cartilage.
  • Removal of loose bodies (cartilage or bone).
  • Micro-fracturing with Plasma-Rich Platelet (PRP) infusion.
  • Lateral Retinacular release.

Meniscal Cartilage Surgery

The meniscus is a commonly injured structure in the knee. It can be torn at any age. In young people, the meniscus is a strong and supple structure and so injuries usually require a lot of force such as in sporting injuries. As one ages, the meniscus begins to degenerate (as its blood supply is quite poor), it loses its tensile strength and so tears can occur from relatively minor injuries or from repetitive loading over time.

Surgery of meniscal tears involves removal of the torn area (meniscectomy) which has a poor blood supply and little chance of repairing. The aim of the surgery is to reduce the mechanical problem which the torn meniscus is creating, and to prevent further damage to the meniscus. Removing the torn meniscus can potentially result in early onset of osteoarthritis due to loss of the menisci’s shock adsorbing function. This risk is reduced by only removing that part of the meniscus which is no longer working. 

Removal of Damaged or Unstable Articular Hyaline Cartilage

The main component of the joint surface is a special tissue called hyaline cartilage. This articular cartilage can be damaged by injury or normal wear and tear. Arthroscopic lavage and debridement is a cleaning up procedure of the knee joint. It does not repair the cartilage but is used as a palliative treatment to reduce pain, mechanical restriction and inflammation.

Removal of Loose Bodies (bone or cartilage)

Loose bodies in the knee joint are small fragments of bone or cartilage that move freely around the knee in joint fluid or synovium. They can hinder the joint movement by getting caught in flexion and extension movements.

Micro-Fracturing and Infusion of Plasma-rich Platelets (PCP)

Damaged joint surface (hyaline cartilage) can lead to arthritis of the joint. The cartilage does not heal itself well and surgical techniques have been developed to stimulate the growth of new cartilage.

Micro-fracturing is a technique to stimulate new cartilage growth. The damaged cartilage is drilled or punched until the underlying bone is exposed. The perforated sub-chondral bone generates a blood clot within the defect and the healing process involves the generation of fibro-cartilage. This process has been shown to be augmented by the infusion of autologous Plasma-Rich Platelets (produced by centrifuging patients own blood) into the joint. The generated fibro-cartilage is weaker than hyaline cartilage and it is likely that it will wear away within a few years. Micro-fracturing should be regarded as an “intermediate step” – it slows the progression of the arthritis. It can take several months for the fibro-cartilage to develop after micro-fracturing and PRP infusion, and requires 6 weeks of Non-Weight Bearing associated with a programme of free knee movement. This has a considerable implication in rehabilitation and is distinct from most knee arthroscopic recovery.

Lateral Reticular Repair

Arthroscopic Lateral Retinacular Release is a procedure performed to correct problems of the patella (knee cap). Lateral release is performed when the patella becomes misaligned and does not track (move over the knee joint) properly. Tightness of the retinaculum, (a fibrous-like tissue), usually causes this condition. Some patients are genetically predisposed to retinacular tightness while in others it follows a twisting injury or blow to the knee cap. When the patellae are injured in this way, the retinaculum shrinks and gets tough which causes the knee cap to mal-track.

Lateral Release involves cutting the tight retinaculum to allow normal tracking of the patella. This allows the patella to slide toward the centre of the femoral groove and so return a normal tracking of the patella-femoral joint.

Pain after surgery can usually managed with simple analgesia. If there is discomfort walking, crutches may be used for the first week.

Pre-operative Instructions

Once surgery is recommended, Dr Lane will discuss the proposed procedure with the patient. Information leaflets covering the procedure, surgical risks and knee arthroscopy after-care will be supplied for your information. 

Anti-inflammatory drugs such as Feldene, Naprosyn, Brufen, Ibuprofen, Indocid, Voltaren, Mobic and Celebrex should be stopped 5 days before surgery. These drugs increase the risk of bleeding. Aspirin or other blood thinning drug usage prior to theatre should be discussed with Dr Lane as this would depend on the patients underlying medical condition. The knee to be operated on should be free of cuts, scratches and sores as this can increase the risk of infection. If there is damaged skin in the area that has to be operated on, then it is highly likely that the operation will be postponed. The patient is also encouraged not to smoke prior to the operation to reduce the risk of deep venous thrombosis.

Almost all knee arthroscopy surgery is done as a day procedure. You will be given clear instructions when to attend the hospital depending on your surgery time. You are advised to take your knee X rays or scans, Medicare, DVA or private health care cards and not to eat or drink anything 6 hours prior to your procedure. Once your details are taken at the admissions area:

  • You will be admitted by the duty nurse and baseline observations taken.
  • Theatre gown and clean disposable underwear given to wear.
  • The knee will be inspected by the nursing staff and anti-septic applied to the leg and then covered with a sterile drape.
  • The other leg will have a TED stocking applied to your legs reduce the risk of thrombosis after surgery.

You will be taken from the Day Hospital to the theatre complex by the nursing staff and then to the anaesthetic bay. There you will meet Dr Lane and your anaesthetist. Knee arthroscopy is usually performed with the patient asleep under a general anaesthetic. It is possible to do the procedure using a spinal or epidural anaesthetic technique.

Procedure

When the patient is asleep in theatre, a tourniquet is applied to the thigh. This gives the surgeon a blood-less field for surgery. The skin is then washed with a sterilising solution and sterile drapes covers the patient leaving a window for the operative site. 

When the arthroscopic surgery is finished, the incision sites are closed with steri-stripes or occasionally sutured (if large incision made), and then covered with Primapore band aids. Local anaesthetic combined with morphine (unless the patient is allergic) and occasionally a steroid like solution (if evidence of inflammation in the joint) is injected into the joint to aid post-operative pain relief. The leg is then covered with a bulky outer dressing – velband (padding) with outer crepe bandage.

The procedure normally takes around 30 to 60 minutes depending on the complexity of the surgery. 

Post-operative Instructions

After the procedure, the patient will be taken to the recovery room for a brief period and when fully awake and observations stable, taken back to the day Ward. Dr Lane usually discusses the operative findings with the patient prior to discharge. Most patients are able to go home within one or two hours after their knee arthroscopy. Patients must be taken home by a family member or a friend when they are discharged from hospital.

Recovery from surgery is usually rapid. Rest and elevation are particularly important for the first day or two to reduce pain and swelling.

  • Pain relief – Simple analgesia, such as paracetamol or paracetamol combined with codeine, is usually adequate to manage pain.
  • Walking – For most procedures (but not following micro-fracturing) walking may be done as soon as possible. Crutches are usually not required
  • Wound care – The incision and dressing over the knee need to be kept clean and dry. The outer bulky dressing may be removed after the third day. The Primapore band aids over the wound should not be removed for 10 days.
  • Exercise programme – Gentle exercise can begin once the pain and swelling has decreased - usually after the first day or two. An exercise programme is given to each patient with clear instructions to follow.
  • Driving – This may be done as soon as able unless otherwise directed. You will not be able to drive yourself home from hospital. Most people will avoid driving for 3 to 4 days.
  • Work – Clerical work - it is usually OK to resume work in approximately one week. Manual work - moderate duties - 2 weeks off work. Heavy Duties - 3 to 4 weeks off work.
  • Sport – No sport for 3 weeks which includes leg raises and resisted exercises.

Patient will be seen by Dr Lane at his rooms, two to three weeks after the procedure. The operative findings will be discussed with patients and photographs given of procedure. 

The outcome of the knee arthroscopy depends on what the surgeon has found within the knee joint and the degree of damage present in the knee. Recovery time varies markedly from patient to patient, and not all arthroscopies are the same. If there are significant degenerative changes in the knee joint (osteoarthritis) full recovery may not occur. Most patients who have meniscal tears or simple removal of loose bodies make a full recovery.

Risks

General risks (rare) associated with Anaesthetic

  • Death.
  • Heart attack.
  • Stroke.
  • Pneumonia.

Local risks (uncommon)

  • Infection.
  • Nerve palsy.
  • Bleeding.
  • Complex regional pain syndrome.
  • Deep venous thrombosis

Patients who are smokers, diabetic or have multiple pre-existing medical conditions are at a higher risk of complications.

The patient should contact Dr Lane's rooms if any of the following symptoms occur:

  • Warmth and redness around the knee.
  • Fever, sweats or shakes.
  • Significant pain not responding to rest, elevation and simple painkillers.
  • Pain behind the calf muscle at the back of the knee.