Knee arthroscopy can be either diagnostic or therapeutic:-
Diagnostic- It is very unusual to perform diagnostic knee arthroscopy as most knee conditions can be diagnosed before surgery. However, it is most likely to be used in the assessment of pain after knee replacement. If local anaesthetic injection abolished the pain yet there is uncertainty about the diagnosis/cause of the knee pain despite investigation such as X-ray, MRI, CT, Bone scan etc. then knee arthroscopy is a useful additional investigation. Mr Ashworth has reported a very rare causes of pain after knee replacement diagnosed and treated by arthroscopy click here for the paper, others are now reporting this issue (click here for other paper) as well as 2 further very rare cases treated with knee arthroscopy also resulting in complete pain relief (Hoffa's fat pad excision and debridement of impinging popliteus tendon on the plastic edge of the posterior lateral part of the knee replacement .
Therapeutic- Knee arthroscopy can treat meniscal and chondral injuries as well as patello-femoral pain (with chondral debridement or lateral release). It is also used to remove loose bodies . Click here for link to microfracture treatment for full thickness cartilage injuries.
The operation is performed under a brief general anaesthetic and takes an average of 25 minutes.
This surgery is nearly always performed as a day-case
Numbness from the small skin incision
Very rarely, numbness and weakness of the foot/ankle
Temporary flare of pain most settle but occasionally a cortisone injection is needed to help this flare settle
Failure to resolve the original pain and thus the need for further treatment up to and including knee replacement surgery