Ortho - Elbow

• The elbow complex consists of three synovial joints: humeroulnar, humeroradial, and proximal radioulnar.

Joint Types

• Humeroulnar joint: synovial hinge joint
• Humeroradial joint: synovial, ellipsoidal/gliding
• Proximal Radioulnar joint: synovial pivot joint

Articulating Surfaces

• Humeroulnar: Trochlea of humerus with trochlear notch of the ulna
• Humeroradial: Capitulum of the humerus with the head of the radius
• Proximal Radioulnar: Head of the radius with the radial notch of the ulna

Capsular Strength/Coaptation

• Humeroulnar joint has weak-moderate coaptation
• Humeroradial joint has weak coaptation.
• Proximal Radioulnar joint has weak coaptation.

Ligaments

• Ulnar Collateral Ligament with a triangular shape comprising of three bands.
  • Anterior band stems from the medial epicondyle to the medial edge of coronoid process
  • Posterior band connects the medial epicondyle and olecranon process
  • Transverse band stabilizes the distal attachments of ant. & post. bands
• Ulnar Collateral Ligament resists VALGUS stress
• Radial Collateral Ligament has a V-shape and is located on the underside of the lateral epicondyle, connecting to the annular ligament and radial notch
• Radial Collateral Ligament resists VARUS stress
• Annular Ligament: primary stabilizer of the proximal radioulnar joint.
  • Anchors the head of the radius to the radial notch
  • Prevents inferior distraction of the radius
  • Damage can occur in children from jerking movements, resulting in a 'pulled-elbow'
• Quadrate Ligament: an inferior thickening of the joint capsule.
  • Posterior fibers become taut with pronation
  • Anterior fibers become taut with supination

Extras

• Interosseous Membrane: dissipates force and stabilizes both radioulnar joints
• Prevents proximal radius displacement on ulna during pushing movements
• Oblique Cord: originates at the radial notch of the ulna and inserts on the medial surface of the radius neck
• The Oblique Cord Prevents radius displacement on ulna, especially during pulling movements
• Ligament of Struthers: Found in 1% of the population.

Osteokinematics

• Humeroulnar joint: 1 degree of freedom for flexion and extension
• Humeroradial joint: 2 degrees of freedom, flexion-extension, supination-pronation
• Proximal Radioulnar: 1 degree of freedom for supination and pronation

Arthrokinematics

• Humeroulnar: the trochlea of the humerus is convex in the anterior/posterior direction and concave in the medial/lateral direction
• Humeroradial: the capitulum of the humerus is convex and the radial head is concave
• Proximal Radioulnar: the head of the radius is convex and the radial notch of ulna is concave

Resting Position

• Humeroulnar: 70° flexion with 10° supination
• Humeroradial: full extension and supination
• Proximal Radioulnar: 70° flexion with 35° supination

Closed Pack Position

• Humeroulnar: Full extension and supination
• Humeroradial: 90° flexion and 5° supination
• Proximal Radioulnar: 5° supination and full extension

Capsular Pattern

• Humeroulnar: Flexion is more limited than extension
• Humeroradial: Supination and pronation are limited only if severe
• Proximal Radioulnar: supination = pronation

ROM and End Feel

• Flexion (HU and HR): 0-150°, soft
• Extension (HU and HR): 0-5°, hard
• Supination (HR and PRU): 0-90°, firm
• Pronation (HR and PRU): 0-70/90°, firm/hard

Other key points

• The three true joints of the elbow share one joint capsule
• Injury to any one joint will affect the whole elbow complex
• Joint effusion/edema is evident in the triangular space between the radial head, tip of the olecranon, and lateral epicondyle.

Biomechanics

• The elbow has a normal slight valgus carrying angle
• On full EXTENSION, the MEDIAL part of the olecranon is not in contact with the trochlea (medial gap)
• On full FLEXION the LATERAL part of the olecranon is not in contact with the trochlea (lateral gap)

Mid Radioulnar Joint

• Radius connection to ulna via the interosseous membrane
• The interosseous membrane is taut midway between supination and pronation (neutral position)
• The interosseous membrane prevents proximal displacement of the radius on the ulna, which most likely occurs with pushing movements
• The interosseous membrane Helps to dissipate forces from the hand so they are less at the elbow
• The oblique cord runs at right angles to the interosseous membrane and assists in preventing distal displacement of the radius on the ulna.

3rd Order Lever

• The elbow functions as a 3rd order lever with the fulcrum at the trochlea, effort from muscle attachments, and load as the weight in the hand
• Load in the hand is 10x more at the elbow joint
• The joint has poor mechanical advantage
• The joint is a good speed multiplier

Tendonitis (Tendinopathy)

• Tendonitis is inflammation/degeneration of a tendon due to overuse.
• Treatment involves offloading the tendon to allow recovery and then strengthening it
• Offloading can be achieved by reducing provocative movements and massage to the muscle belly.
• Eccentric resistance exercises are optimal for strengthening tendons.

Assessing for tendonitis

• Pain on AROM or PROM in the antagonist direction
• Pain with resisted contraction (RROM or MMT) of the affected muscle, specifically with an eccentric component.
• Pain with palpation

Most Commonly Affected Tendons

• Common Extensor Tendon:
  • Most common; 'Tennis elbow'
  • Provoked by repetitive, forceful extension, supination, radial deviation.
  • ECR Brevis is most commonly affected due to irritation from the radial head during pronation-supination movements
  • Can be most tender at the supracondylar ridge, epicondyle, or just distal over the bulk of the tendon
• Common Flexor Tendon:
  • 'Golfer's elbow'
  • Provoked by repetitive, forceful pronation and flexion
  • Pronator teres most common, followed by FC radialis
  • Provoked by forceful gripping.
• Triceps Brachii Tendon:
  • 'Posterior tennis elbow'

Bursitis (Olecranon)

• Usually due to trauma to the elbow or overuse of surrounding structures.
• Any activity that involves a lot of time on the elbows
• Bursitis is aggravated by compression
• PROM empty end-feel

Differentiation from Tendonitis

• Pain with compression that does not get worse with load, especially eccentric load

Fractures

• Assessment includes ROM (Active, Passive, and Resisted)
  • Palpation is contraindicated before consolidation.
• Further testing may include assessment of perfusion, swelling, muscle tone, and tissue health
• Precautions during immobilization include avoiding tractioning before union and avoiding heat or ice if hardware has been used

Nursemaid's Elbow

• Radial head subluxation commonly caused by pulling on a child's arm
• Caused by the conical shape of the radial head before 8 years old
• Annular ligament allows for the subluxation
• Commonly reduced by a doctor or chiropractor

Key Points for Orthopedic Tests

• Cozen's test (method 1) is for lateral epicondylitis
  • A positive test consists of sudden severe pain at lat epicondyle, supracondylar ridge, or CET
  • Indication: Complaints of pain in the area especially if MOI is repetitive muscle-use of forearm

Home Care Principles

• Therapy programs should:
  • Not cause pain/inflammation
  • Be progressive and gradual
  • Start as early as possible (no inflammation presence)
• Exercise Selection Considerations:
  • Loaded exercises performed in mid-range
  • Exercises should increase range unweighted
  • Passive before active exercises are prescribed
  • Isometric exercises before eccentric exercises which should be done before plyometric exercises
  • Open chain exercises before closed chain exercises

Signs of an Overly Challenging Program

• Discomfort that lasts more than 2 hours in the acute/subacute stage.
• Discomfort lasts more than 4 hours in the chronic stage.
• Reliance on pain medication to control discomfort.
• Increased pain at rest, extreme fatigue, rebound muscle spasm, or increased weakness