What is the extensor mechanism of the knee comprised of ?
Constitutes of the tibial tuberosity, the patellar tendon, the patellar, the quadriceps tendon and the quadriceps muscles.
Describe the mechanism of how patellar tendon or quadriceps tendon ruptures occur?
With rapid contractile force:
e.g. after lifting a heavy weight, after a fall
Or spontaneously in a severely degenerate tendon
What is the difference in who patellar tendon ruptures and quadricep ruptures tend to occur in ?
patellar tendon ruptures tend to occur in people <40
quadriceps tendon ruptures tend to occur in >40
What are some of the predisposing factors to patellor or quadricep tendon ruptures ?
History of tendonitis
- Chronic steroid use or abuse (body builders)
- Chronic renal failure.
- Quinolone antibiotics (eg ciprofloxacin) can predispose to tendonitis/ruptures
Should steroid injections be avoided in people with tendonitis of the extensor mechanism of the knee ?
Yes! it comes with a high risk of tendon rupture
What test in your examination of acute knee injury would assess if the extensor mechanism of the knee is intact or if there is injury to it ?
SLR (straight leg raise)
What is the results of the SLR when a patient has A disruption of the quadriceps tendon, patella, or patellar tendon e.g. talking about ruptures of the tendons
The patient may not be able to perform SLR
If a patient has a partial tear of a tendon in the extensor mechanism of the knee what may the results of the SLR be ?
May have some extensor mechanism function (so may be able to perform it) but have reduced power e.g. when putting pressure on the SLR they may not be able to keep it up
What is the treatment of tendon ruptures/ substantiale tears involving the extensor mechanism of the knee ?
Surgical with tendon to tendon repair or reattachment of the tendon to the patella
What are the signs of patellar and quariceps tendon ruputres ?
Inability to straight leg raise or weight bear.
A palpable gap in the patellar or quadriceps tendon (although this may be difficult to detect owing to swelling).
Change in height of the patella. (quadriceps tendon rupture patellar displaced inferiorly) (patellar tendon rupture, patellar displaced superiorly)
What is patellofemoral dysfunction ?
It is described as an ill-defined ach producing anterior knee pain (this is a result of (mechanical and biochemical changes to the patellofemoral joint)
What are the common signs/symptoms of patellofemoral dysfunction ?
- Anterior knee pain - worse going downhill
- Griniding or clicking sensation at the front of the knee
- Stiffness after prolonged sitting causing “pseudolocking”
What is the treatment of patellofemoral dysfunction?
- 1st line - Physio to strengthen the muscles
- Adjunct - NSAID's
- Adjunct - Patellar taping may help
How does patellar dislocation commonly occur ?
By a direct blow or sudden twist of the knee
What may be torn when the patellar dislocates ?
The patellofemoral ligament
When the patellar dislocates what way does it usually displace ?
What type of swelling occurs following a patellar dislocation (same idea as what type of swelling occurs following an ACL rupture)
A lipo‐haemarthrosis occurs
What is the treatment of patellar dislocation ?