Shoulder Complex (Part II) - The Unstable Shoulder

SHOULDER INSTABILITY

Glenohumeral instability is the inability to maintain the humeral head in the glenoid fossa.

Classification Scheme:

1. Degree

2. Frequency

3. Etiology

4. Direction

Introduction to the Shoulder Complex (Part I) - What structures are involved in providing shoulder stability?

Introduction

The shoulder is the most mobile joint in the human body. A normal shoulder precisely constrains the humeral head to the centre of the glenoid cavity throughout most of the arc of movement. 

Anatomy

Glenohumeral joint (GHJ):

• Multiaxial ball and socket synovial joint
• Large ROM (range of motion) up to 180 deg with 3 degrees of freedom (flexion/extension, abduction/adduction, internal rotation/external rotation)
• Glenoid fossa is relatively shallow and provides little bony support for stability of the humeral head (humeral head = 3 x glenoid fossa; at most, only ~25% of humeral head is in contact with glenoid fossa in any given position)

Shoulder Stability

Shoulder stability is the result of a complex interaction between static and dynamic restraints.

• Static stabilisers (capsule, ligaments, labrum) act as concave structures to deepen the glenoid fossa.
• Dynamic stabilisers include rotator cuff and surrounding larger muscles that provide scapular stability (serratus anterior, lat dorsi, rhomboids, trapezius, pectoralis)

Review on LARS - An alternative for ligament reconstruction

I was asked about the efficacy of LARS as an alternative surgical option for ACL reconstruction. 

In recent years, the use of LARS ligaments have been increasing with promising clinical results. In fact, these ligaments have been in clinical use for over 15 years. LARS stands for Ligament Augmentation & Reconstruction System, and these artificial ligaments are intended for the intra or extra-articular reconstruction of ruptured ligaments.

Knee injury: ACL (Part II)

In follow-up to my previous article on "Knee injury: ACL (Part I)", here is the 2nd half of my discussion to provide an overview of ACL surgery and post-op rehabilitation.

Who will benefit from surgery?

• Individuals with active lifestyles
• Individuals involved in high-level sporting activities (eg. soccer, basketball, netball, footy, skiing, etc)
• Those with recurrent knee instability due to ACL deficiency
• Those wishing to protect their knee joint and cartilage from future damage
• Individuals who have attempted and failed conservative management with recurrent knee pain and instability