Lecture 6 Ligament and joint injuries Flashcards
Ligaments (article): structure
- Dense bands of collagen tissue
- Collagen, elastin, proteoglycan, and other proteins
- Vary in size, shape, orientation and location
Ligaments(article) function
- Connect one bone to another → Passive stabilization of the joints
- Ligaments can creep
- Serve important proprioceptive function
Ligaments(article): response to injury
- Healing follows the constant pattern
- Ligament scars have inferior creep
properties - Ligament injury → decreased
proprioception
Joint stability
- depends on the interaction between the passive, active and neural subsystems
- passive subsystem consists of non-contractile connective tissues, ligaments, cartilage, second category of soft tissue unable to contract and relax
- active subsystem is controlled by the neural subsystem to provide dynamic joint stability
Types of ligaments
intre-articular ligaments, extra-articular ligaments, capsular ligaments
- all have different healing capacities
Intra-articular ligaments
Primary stabilizer of the joint, acl, pcl, in the joint
e.g., cruciate ligaments of the knee
Extra-articular ligaments
-support joint
e.g., calcaneofibular ligament
Capsular ligaments
- Thickening of joint, higher blood, higher healing
e.g., anterior talofibular ligament
Adaption to training
- adapt slowly to increased loading, but weaken very rapidly as a result of immobilization
- adapt to loading by increasing the cross-sectional area
- normal everyday activity is sufficient to maintain mechanical properties
- systematic training can increase ligament strength by 10-20%
Stress-strain curve
- If force causes more than a 4% change of length the collagen fibres will start to rupture
Ligament injuries
- typically injured because of acute trauma
- single identifiable event of injury, mid-tearing couple fibres to complete tear
- mechanism: sudden overload-> ligament is stretched (joint in an extreme position)
- repetitive injuries rare, but can occur as the ligament is gradually stretched out
Grade 1 ligament injury
-mild
- structural damage on the microscopic level
- no instability
grade 2 ligament injury
- moderate
-partial tear
-swelling and pain - no/limited instability
Grage 3 ligament injury
- severe
- full rupture
- significant swelling
- instability
Mechanism of injury
- Felt my knee-cap go out- Patellar dislocation/subluxation
- Hit from lateral side - valgus- MCL +/- ACL
- Valgus/external rotation - with or
without contact- ACL +/- MCL +/- lateral meniscus +/- bone bruise - Direct blow to anterior tibia- PCL
- Hyperextension injury- ACL
- Minor twist in older individual- Degenerative Meniscal tear
Knee or knee cap?
MPFL
Valgus mechanism of injury
- ACL injury
- MCL sprain
- Lateral dislocation of patella
- Meniscus injury
- Lateral tibial plateau fracture or bone bruise
Hemarthrosis
- bleeding into the joint
- injuries that cause hemarthrosis: acl tear; peripheral meniscus tear; osteochondral injuries; fractures
- injuries that not usually cause hemarthrosis: mcl tear; central meniscus tear; pcl tear; cartilage injury
Anterior cruciate ligament injury
- ACL – 2 bundles
- Anteromedial bundle resists
tibial anterior translation - Posterolateral bundle resists tibial rotation
- No pain fibers, but has proprioceptive fibers
ACL complications
- osteochondral injury
- acl injury and meniscus tear
- osteoarthritis în 15-20 years
- unhappy triad
ACL treatment- goals
- Goal is to prevent recurrent giving way: to prevent subsequent injuries, such as osteochondral injuries and meniscus injuries
ACL treatment- options
Three options( as for any unstable joint):
* Modification of activity (no twisting activity)
* Bracing for light twisting activity
* ACL reconstruction (although functional – never normal)
ACL reconstruction
- The graft is weakest at 3 to 6 months!
- High re-injury rates over 2 years after
reconstruction
ACL injury
- anatomical factors
- biomechanical factors
- neuromuscular factors
- hormonal factors
- training related factors
Prevention of ACL injuries
- Modifiable risk factors
- Weak hip abductors an external
rotators - Increased knee abduction moments during cutting and landing
- Knee Control training program
- Adolescent female soccer players
(n=4600) - 64% reduction in the rate of ACL injury was seen in the intervention group
ACL injuries on the rise
- Although current ACL injury prevention training programs have been successful in reducing injuries in controlled research settings, the real- world ACL injury rate remains high, and even continues to increase
- The ACL injury rate for girls/women has not changed in over 20 years, and they remain up to 6 times more likely to experience injury compared with boys/men
- In addition, as many as 40% sustain a recurrent ACL injury in the same knee or new ACL injury in the contralateral knee
Shoulder dislocation and sublixation
- common injuries in contact sports
Dislocation
complete separation of articulating bones
Subluxation
partial dislocation of articulating bones
typical mechanism
- direct blow to the posterior aspect of the shoulder
- landing on outstretched arm
- anterior dislocation, fracture dislocation
Diagnosis and treatment
- History and physical exmination
- imaging
- reduction of the shoulder (after confirmed diagnosis)
- protection from re-injury
- rehabilitation period prior return to sport
High risk of recurrence
-50-90% depending the type of sport and shoulder dominance
- surgical management (in high-risk population)
- rehabilitation of the shoulder is critical to long-term function
Prevention of shoulder dislocations and subluxations?
- strength
-proper technique - neuromuscular training
- joint position sense
