ANATOMY OF ELBOW

- Vinaykumar .S. Appannavar

• Elbow joint is a hinge type of joint, formed by the articulation between the lower end of the humerus with ulna, and with the head of the radius• Humeroulnar articulation• Humeroradial articulation and• Radioulnar articulation

• The lower end of the humerus is enlarged to form the trochlea medially and capitulum laterally•Medial to the trochlea is medial epicondyle and lateral to the

capitulum is the lateral epicondyle

• The two epicondyles are continuation of the medial and lateral supracondylar ridges respectively• Humeroulnar articulation is responsible for alignment,

stability and strength.• The other two joints help in forearm and hand motion and

position.

• Three bony points relationship :

• Carrying angle :

• Stability of the elbow :

•Muscles common flexors (originate from medial epicondyle) • pronator teres • flexor carpi radialis • Palmaris longus • Flexor Digitorum Superficialis • Flexor Carpi Ulnaris

• common extensors (originate from lateral epicondyle) • anconeus • Extensor carpi radialis longus• Extensor carpi radialis brevis• extensor digitorum comminus • Extensor digiti minimi • Extensor carpi ulnaris

INTERCONDYLAR FRACTURE OF THE

HUMERUS

• It is a common fracture in adults• It results from a fall on the point of the elbow so the

olecranon is driven into the distal humerus, splitting the two humeral condyles apart

•Mechanism of injury:•

Is by a force directed towards an elbow which is flexed > 90° which causes the ulna to drive against the trochlea• The fracture pattern may be

related to the position of elbow flexion when the load is applied

• Riseborough and Radin Classification• Type I: Nondisplaced• Type II: Slight displacement with no rotation between the condylar fragment.• Type III: Displacement with rotation• Type IV: Severe comminution of the articular surface

Evaluation

•Physical exam• Soft tissue envelope• Vascular status• Radial and ulnar pulses

• Neurologic status• Radial nerve - most commonly injured• 14 cm proximal to the lateral epicondyle• 20 cm proximal to the medial epicondyle

• Median nerve - rarely injured• Ulnar nerve

•Radiographic exam• Anterior-posterior and lateral radiographs• Traction views may be helpful to evaluate intra-articular

extension and for pre-operative planning (creates a partial reduction via ligamentotaxis)• Traction removes overlap

• CT scan helpful in selected cases• Comminuted capitellum or trochlea• Orientation of CT cut planes can be confusing

Pathoanatomy • The fracture line may take the shape of a T or Y. The fracture is

generally badly comminuted and displaced.

• Classification of Mehne and Matta:1. High T.2. Low T3. Y-type4. H-type.5. Medial.6. Lateral• The Mehne and Matta classification describes the most often

encountered fracture patterns intraoperatively.

•Clinical Features:

1. The elbow maybe held in 90° flexion and forearm is kept pronated2. Crepitus may be elicited3. Independent mobility of the medial and lateral condyle can be elicited4. The normal 3 point bony relationship between the olecranon, medial epicondyle and lateral epicondyle is lost

Diagnosis :• There is generally severe pain, swelling, ecchymosis and crepitus

around the elbow• X-Rays:

Standard AP and lateral views are obtainedCT scan is helpful to further delineate the fracture pattern

Treatment :• It depends upon the displacement. An undisplaced fracture needs

support in an above – elbow plaster slab for 3-4 weeks, followed by exercises • A displaced fracture is treated generally by open reduction and

internal fixation • Operative Treatment• Open reduction and internal fixation:

• Restores articular congruity• Interfragmentary screws and dual-plate fixation: One plate is placed medially and another plate posterolaterally. Reconstruction plate and one-third plate are used commonly.• Total elbow arthroplasty (semi constrained): May be considered in markedly comminuted fractures and in fractures with osteoporotic bone.

Outcomes •Most daily activities can be accomplished with the following

final motion arcs:• 30 –130 degrees extension-flexion• 50 – 50 degrees pronation-supination

• Outcomes based on pain and function• Patients not necessarily satisfied with above motion arcs

• Good elbow flexion is often the first to return• Extension seems to progress more slowly• Supination/pronation usually unaffected• Pain- 25 % of patients describe exertional pain•What patients may expect, for example:• Lose 10-25 degs of flexion and extension• Maintain full supination and pronation• Decrease in muscle strength• Overall:• Good/excellent 75%

• Factors most likely to affect outcome• Severity of injury• Occurrence of a complication

Complications • Failure of fixation• Associated with stability of operative fixation• K-wire fixation alone is inadequate• Adult distal humerus is much different from pediatric distal humerus

• If diagnosed early, revision fixation indicated• Late fixation failure must be tailored to radiographic healing and

patient symptoms• Nonunion of distal humerus• Uncommon• Usually a failure of fixation• Symptomatic treatment• Bone graft with revision plating

•Non-union of olecranon osteotomy• Rates as high as 5% or more• Chevron osteotomy has a lower rate• Treated with bone graft occasionally and

revision fixation• Excision of proximal fragment is salvage• 50% of olecranon must remain for joint stability

• Infection• Range 0-6% • Highest for open fractures• No style of fixation has a higher rate than any

other

•Ulnar nerve palsy• 8-20% incidence• Reasons: operative manipulation, hardware prominence,

inadequate release• Results of neurolysis (McKee, et al)• 1 excellent result• 17 good results• 2 poor results (secondary to failure of reconstruction)

• Prevention best treatment (although routine transposition is of unknown importance)

•Painful implants• The most common complaint• Common location• Olecranon • Medial implants (over medial epicondyle)• Lateral implants (some plates prominent over posterior-lateral

aspect of lateral condyle)• Implant removal• After fracture union• Patient may need to restrict activity for 6-12 weeks

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