anatomy

Deformities

Mallet

- DIP flexed

- MTP / PIPJ neutral

Hammer 

- PIP flexion

- DIPJ neutral / extended

Simple - MTP not involved

Complex - MTP hyper-extended

Claw 

- PIPJ and DIPJ flexed

- MTPJ hyperextended

Curly toe 

- PIP and DIP flexion

Anatomy

1.  TFCC 

- central articular disc

- TFCC is major stabiliser of DRUJ

- arises ulnar aspect of lunate fossa of radius

- inserts fovea at base of ulna styloid

2.  Dorsal and Palmar Radio-Ulna ligaments 

Thick fibrous structures

- from ulna styloid

- important stabilises of DRUJ

In normal wrist

- Dorsal RU ligament tight in pronation

Nerve supply

- C7, C8, T1 

- nerve picks up some branches of C7 from the lateral cord

Origin

- direct continuation medial cord

- runs between the brachial artery and the vein in the arm

- behind MCNFA

Arm

- pierces the medial intermuscular septum to run in posterior compartment

- runs anterior to the triceps

Elbow

Epidemiology

Traumatic initial cause in 95%

M:F 2:1

Age of initial dislocation inversely related to recurrence rate

- patients younger than 20 have a redislocation rate of 90%

- between 20 - 40 years, redislocation rate of 60%

- patients > 40 years have a 10% rate of dislocation but a higher rate of cuff tears (up to 40% in patients > 60yrs)

Anatomy & Stability

1. Passive Stabilisers

Anatomy

Synovial joint with hyaline cartilage

Has fibrocartilage intra-articular disc

- complete or incomplete

- usually degeneration by 4th decade

Clavicle may lie superior to acromion in normal population

Acromioclavicular Ligaments

Zones

I DIPJ

II Middle Phalanx

III PIPJ

IV Proximal Phalanx

V MCPJ

VI Metacarpal

VII Dorsal Wrist Retinaculum

Definition

Injury to ulnar collateral ligament of thumb MCPJ

Aetiology

Initial description

- chronic laxity of British gamekeeper's thumb's 

- no specific trauma

- secondary to breaking pheasant's neck

Acute trauma

- snow ski

- ball games

Valgus / forced abduction

Anatomy

UCL

Definition

Intra-articular proximal ulna fracture

Anatomy

Articulates with trochlea

- may have a central bare area

Triceps insertion

- via broad aponeurosis which blends with anconeus and CEO

Management

Non operative Management

Undisplaced fracture

- need to ensure triceps mechanism is intact

Epidemiology

2 groups

- young patient with high velocity injury

- older patient with comminuted, osteoporotic fracture

In the second group fixation can be very difficult

Anatomy

Hinged Joint

- trochlea axis is centre of rotation

- 40^o anterior angulation in sagittal plane

Incidence

Lateral : Medial 9:1

Epidemiology

4th & 5th decades

- M = F

- 75% dominant arm 

50% of regular tennis players

- especially > 2 hrs / week

Aetiology

Insertion pathology / Enthesopathy

Over-extension of the elbow with supination / pronation

Anatomy

Lateral epicondyle

- anconeus from posterior face

- ECRB and EDC from anterior face (CEO)