It would be naïve to pretend that all surgery is uncomplicated. One of the major advantages of keyhole surgery, in experienced hands, is that complications can be kept to a minimum. Nevertheless they can occur. Complications may be divided into two categories:

  • 1. Complications during surgery
  • 2. Complications after surgery

Complications During Surgery
Only those complications related to orthopaedic surgery, rather than surgery in general, or anaesthesia, will be mentioned here. Orthopaedic complications include the following:

  • 1. Neurological complications
    Damage to the skin nerves that supply feeling to the area over the kneecap is quite common. This is of no functional significance whatsoever. More major damage to the large nerves that supply the lower leg and foot is rare.
  • 2. Vascular complications
    Major blood vessel damage is rare. It is quite common, however, for patients to bleed following surgery from small skin blood vessels beneath the surgical incisions.
  • 3. Tendon and Ligament damage
  • 4. Articular cartilage damage
  • 5. Incomplete procedure
    Sometimes a surgeon might choose to leave a procedure uncompleted rather than risk too much damage to the patient, particularly so if the area of the joint in question is difficult to reach. Some knees are `tight', often in muscular, athletic individuals, making it hard for a surgeon to reach every nook and cranny.
  • 6. Fracture
  • 7. Tourniquet paralysis
    This is rare (less than 0.5% of cases) and normally resolves within a few hours of the procedure.
  • 8. Broken instruments

Complications After Surgery
These are fortunately rare, but can be tabulated, with their percentage incidence, as follows:

  • Haemarthrosis 1.0%
  • Infection 0.2%
  • Deep-vein thrombosis (DVT) 0 - 7.3%
  • Pulmonary embolism 0 - 3.2%

Haemarthrosis is a term that describes bleeding into a joint. Because the surgical stab incisions are so small there is nowhere for the blood to escape. Consequently it can build up within the knee and may require surgical drainage. It can be quite painful and result in stiffening of the knee joint in the long term.

Complications are also procedure-dependent. Some operations have a higher chance of complications than others. Look at this table, for example:

  • Procedure                    Incidence
  • Lateral release               7.2%
  • ACL reconstruction        3.3%
  • Meniscal repair               1.9%
  • Medial meniscectomy      1.8%
  • Lateral meniscectomy     1.5%

Finally, although they have not been described here, the general complications of all surgery apply and should not be forgotten. Cardiovascular problems, urological problems, gastrointestinal troubles, and others, can occur. Do not forget that surgery is never as simple as it seems!

Few studies exist, if any, to compare the results of arthroscopic procedures with the older-fashioned open surgery. In the short term there is no doubt that arthroscopy shortens length of hospital stay (it is usually a daycase operation) and reduces peri-operative complications. It also allows the surgeon to be more conservative than when using open techniques. This may mean that further procedures will need to be undertaken in the short term. For example, after arthroscopic meniscectomy up to 23% of patients may requires further meniscal resection at a later date.

ACL reconstruction is now big business, although results are variable. Meniscectomy performed in the presence of ACL damage, but without the ACL being reconstructed, will improve symptoms in 84% of patients, although 10% will appear to be worse 4½ years later.

Arthroscopy performed for osteoarthritis of the knee is unpredictable. The aim is to clear out any debris and smooth off irregular surfaces. However, at best 60-80% of patients will have worthwhile relief for 5 years after arthroscopy. Those patients with a knee deformity before surgery tend to fare worse than those with undeformed knees.