Knee Problems – sussing things out in 10 minutes 

Most GPs have 10-15 minutes in a consultation – clearly not long enough to do all the fancy knee tests like McMurrays, Lachmans etc.  Even in experienced hands, these specific examination tests are difficult to perform accurately.  In inexperienced hands, these tests give unreliable results.   Therefore, the aim of this document is to help you decide what sort of knee problem your patient has and whether it needs referral using greater reliance on the history and less on the examination.  

The four commonest knee problems are:  Patello-femoral syndrome, ACL rupture, Menisci problems and arthritis.   We will only be looking at the first three of these.

It might be worth likening these three to a road traffic accident to help you match symptoms and examination findings to the diagnosis:
•	ACL rupture =		major RTA
a dramatic presentation, big symptoms and major exam findings
•	Menisci problems =	moderate RTA 
a less dramatic presentation, moderate symptoms and moderate exam findings
•	Patello-fem synd. = 	minor RTA/near miss
minor dramatic findings

History
Remember, it is the combination of these symptoms that will give you a clue as to what is going on.  Do not try to use symptoms in isolation, although they are presented here in this way.

Presentation after the event
<24h 		Think of ACL rupture
24-48h		Think of menisci tear
Days/Weeks	Patello-femoral syndrome

This doesn’t mean an ACL rupture wont present to you late.  For instance, they might have present FIRST to A&E the same day as the event!

Swelling
<24 and LARGE	Think ACL rupture
24-48h and moderate	Think meniscal tear
Very minor swelling	?Patello-femoral syndrome

Pain
All over the knee 	ACL rupture (cos the swelling is so large)
Medial Joint line	Menical tear
Anterolateral 		Patello-femoral syndrome

Biomechanics
Most people cant recall the biomechanics of the injury because of the hurly-burly’ness of the match/event.   So, it is often a fruitless enquiry to ask “which way your knee blah blah blah on impact”.  However, ask specific questions relating to the following as they can usually remember these:

Twisting injury		Think Mensici tear
Knee giving away	ie patient managed to get up, hobbled around but then knee gave way		
Think Mensici tear
Locking		Think Mensici tear
Snap/Crackle/Pop	Think ACL rupture (not rice crispies!)

What could the patient do after the injury?
Unable to continue 	Think ACL tear
Able to hobble about	Think mensical tear

One other thing to mention about Patello-femoral syndrome:
Usually common in prepubescent girls but can happen in adults to eg those who have just taken up long distance walking/hill climbing.  Worse on going downstair or descending a hill (patients often report having to take a break going down hill not up hill because of the pain).   Knee flexion activities eg squatting, crouching, driving, sitting at the cinema makes the pain worse.
Finally

Examination
•	ACL rupture = very large swollen knee, patient in major distress, can hardly walk
•	Mensical tear = swelling over night, moderate swelling, medial joint line pain, can just about hobble
•	Patello femoral syndrome = anterolateral knee pain, pushing the patella laterally causes pains

Referral
ACL tears need urgent referral for repair
Mensci problems need to be referred within the week
Patello-femoral syndrome – refer to physio or tape the patella by  pulling it medially and taping it using duck tape.