Knee & Sports Flashcards
6 main phases of throwing
- wind up
- early cocking
- late cocking
- acceleration
- deceleration
- follow-through
What is the most harmful phage of throwing?
- Deceleration phase
- eccentric contraction of all muscles is required to slow down arm motion, highest torque phase
what phase of throwing will cause greatest pain w/ medial (ulnar) collateral ligament stain/injury?
Late cocking phase
-this is the phase of greatest valgus overload
Local dynamic stability of the elbow is provided primarily by what 2 structures?
- Flexor digitorum superficialis
- Flexor carpi ulnaris
- these provide dynamic joint compression across the elbow joint and may be protective to the static restraints such as the ulnar collateral ligament. It also emphasizes the need to strengthen distant muscles in the forearm to assist w/ elbow biomechanics and potentially prevent injury
MCL of the elbow anatomy
- divided into anterior and posterior bundles
- anterior bundle subdivided into anterior and posterior bands
- anterior band of anterior bundle is primary restraint to valgus stress at 30 degrees, 60 degrees, and 90 degrees
- posterior band of anterior bundle is primary restraint at 120 degrees
- posterior bundle is a secondary stabilizer at 30 degrees of flexion, and not susceptible to valgus load when the anterior bundle is intact
physical exam of medial elbow pathology
- pain, instability, loss of velocity or control, or w/ ulnar nerve symptoms
- the MOVING VALGUS STRESS TEST is performed by applying a valgus stress to a maximally flexed elbow, then passively extending the elbow
- reproduction of sx in the mid arc of flexion suggests MCL insufficiency
- pain at end point of extension suggests posterior compartment sx
pain is most significant during which phase of throwing in valgus extension overload (pitcher’s elbow) syndrome?
acceleration phase
excessive stresses during the late cocking and acceleration phase of throwing can injure what?
anterior band of the MCL
what is the insertion site of the anterior bundle of the MCL of elbow?
Sublime tubercle
Interval when performing an inside-out medial meniscus repair and structure at risk?
-Superficial interval between anterior to pes tendons
-Deep interval is between the medial head of the gastrocnemius and the joint capsule
-Structure at risk is the saphenous nerve
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Interval when performing an inside-out lateral meniscus repair and structure at risk?
- Superficial interval between biceps femoris and IT band
- Deep interval between the lateral head of the gastrocnemius and the joint capsule
- Structure at risk is the peroneal nerve
A tear of the mid portion of a stable discoid lateral meniscus should be treated how?
Partial menisectomy with saucerization
In the anterior cruciate ligament-deficient knee, what structure provides an important secondary restraint to anterior tibial translation?
- Posterior horn of the medial meniscus
- The posterior horn of the medial meniscus is thought to limit anterior tibial translation by acting as a buttress by wedging against the posterior aspect of the medial femoral condyle.
Which of the following risk factors is felt to contribute greatest to the higher rate of ACL rupture in female compared to male athletes?
Neuromuscular factors
- increased valgus moments when jumping and landing and a relative weakness of hamstrings compared to quadriceps are present in female athetes and may contribute to higher ACL tear rates. It has subsequently been shown that neuromuscular training to address these issues can result in a reduction of ACL injuries in select groups of female athletes.
- It appears that increased valgus motion and valgus moments at the knee joint during the impact phase of jump-landing tasks are key predictors of an increased potential for ACL injury in females
A prolonged range of motion deficit following ACL reconstruction has been demonstrated in patients who have a classic bone bruise pattern on MRI after ACL rupture.
- Take away here is that if you see significant bone bruising on MRI with ACL rupture, that patient is at higher risk of difficulty regaining full ROM following repair
- middle third of the lateral femoral condyle and the posterior third of the lateral tibial plateau are the classic locations
