Basic anatomical notes - forearm:

The ulna is dominant for movement at the elbow joint. The radius is dominant for wrist function.

Both bones are connected anatomically and functionally and form a functional unit.

The anatomical connection is represented by the proximal and distal radioulnar junctions and the interosseous membrane.

In terms of the AO classification, the forearm can be divided into proximal part (AO 21), which includes intra-articular (AO 21 B resp. C) and extra-articular (AO 21 A) fractures. Furthermore, there are diaphyseal fractures (AO 22) and finally distal diaphyseal fractures (AO 23) - once again including intra-articular (AO 23 B resp. C) and extra-articular (AO 23 A) fractures

Fractures in the forearm region may occur as isolated fractures of a single bone or as a simultaneous fracture of both bones. A specific type of injury which has to be considered is the combination of fractures of one of the bones with a simultaneous injury to the ligament, typically in the region of proximal or distal radioulnar junction (e.g. Galeazzi or Monteggio fracture).  Because of the predominant bone trauma, these injuries can be easily missed and a thorough clinical examination is important in this case.   

Diagnosis - general

Clinical examination for direct or indirect signs of fracture is the baseline.

Evaluation of blood supply and neurological status of the limb - exclusion of acute ischemia or nerve lesion (pulsation of a.radialis or a.ulnaris, tenderness in the distribution of n.radialis, ulnaris or medianus).  Making a thorough record of the initial condition of the affected limb (i.e. before any therapeutic intervention) may be important not only for later clinical comparison but also for forensic reasons (e.g. was the nerve affected by the injury itself or only after the operation? ).

The next step is to take baseline X-rays in 2 perpendicular projections (typically AP and lateral).  It is important to capture the entire forearm including the elbow and wrist joints, especially in case of positive clinical findings.

CT scanning is usually indicated for intra-articular fractures or in case of ambiguity.

Isolated fractures of the proximal ulna

Fractures of the olecranon ulnae

They occur relatively frequently.  Direct impact is the usual mechanism of injury.  More rarely as an indirect mechanism - by pulling the attachment of the m.triceps brachii.  This almost always concerns intra-articular fractures with typical dislocation by pulling of the tendon of m.triceps brachii.  The defect is usually palpable.

●      Treatment –

○      Surgical - with regard to the typical dislocation,

■      mostly tension cerclage, spong. screw with a washer, angle-stable splint for multiple fractures

○      Conservative - mostly as infracture or fractures without dislocation (uncommon)

■      Plaster fixation for 2-3 weeks in 60-90° flexion followed by an early functional treatment with limited motion under X-ray checks.

Fractures of the processus coronoideus ulnae

They are usually associated with luxation of the elbow joint, and, depending on the size of the broken off fragment and the extent of ligamentary injury with joint instability (recurrent dorsal luxation).

●      Treatment - fragment less than 50% of height - conservative, fractures at the base (occupying more than 50% of the height - affecting the stability of the elbow) - surgical (compression screws, splint osteosynthesis)

Isolated fractures of the proximal radius

The head of the radius or the radiohumeral joint is an important stabilizing element of the elbow joint, it resists rotational forces, valgus stability (internal collateral ligament), lateral stability (lateral ligament. complex).  Fractures usually occur as a result of major violence to the elbow joint and are often part of a compound injury in the elbow region. 

Anatomically, these fractures can be divided into head and collum fractures. Fractures can be simple (e.g. head chisel fracture) or multifractured (comminuted), intra-articular or extra-articular.

●      Treatment

○      Conservatively - fractures without dislocation, cast fixation for 2 weeks, followed by elbow mobilisation, initially without pronosupination movements

○      Surgical - fractures with dislocation

■      Salvage surgeries

●      Tension screw - for simple fractures

●      splint osteosynthesis /LCP splint/ - subcapital and multifractured fractures

■      Replacement of the head with an implant (endoprosthesis) - especially in comminuted fractures without the possibility of a salvage surgery (osteosynthesis), simple extirpation of the head is no longer recommended because of the above-mentioned stabilising function

Diaphyseal fractures of the forearm

Assessment of the mechanism of injury - direct/indirect - is important.

Single bone fracture is usually caused by a direct mechanism (e.g. "nightstick" fracture of the diaphyseal ulna).

Simultaneous fracture of both bones often occurs as a high-energy trauma.

Complex injuries are typical for indirect mechanisms in the sense of fracture of one bone with luxation of the end of the other bone, as mentioned in the introduction

Isolated fractures of the diaphysis of the ulna

●      Treatment

○      Conservative - only for non-dislocated fractures (even so, the treatment is often complicated within the meaning of prolonged healing or non-healing because of mechanical conditions - uninjured second bone preventing compression between fragments, rotational forces), high plaster fixation (above the elbow) for 4 weeks, then functional therapy

○      Surgical - more common, preferable because of significantly shorter fixation and less risk of non-healing.

■      especially splint osteosynthesis according to AO principles (tension screw + neutralizing splint, autocompression splint, bridging splint)

■      Intra-medullary osteosynthesis - as an option, less frequently

Isolated fractures of the diaphysis of the radius

●      Treatment

○      Conservative - only for non-dislocated fractures (rarely)

○      Surgical - similarly to isolated fractures of the ulna - see above.

Combined luxation fractures

●      Monteggio fracture - fracture of the proximal third of the ulna with ventral luxation of the radial head, according to the dislocation of the ulna, we distinguish between the flexion and extension type

○      Treatment

■      Surgical - osteosynthesis of the ulna fracture according to the principles of AO, non-bloody repositioning of the radial head luxation, in case of instability, open repositioning with suture of the lig. anulare

Post-surgically cast for 14 days, then gradual rhb

●      Conservative - mostly in children, closed repositioning and plaster fixation

●      Galeazzi fracture - fracture of the distal third of the radius associated with luxation of the ulna head (in DRUJ = distal radioulnar joint)

○      Treatment

■      Surgical - osteosynthesis of the radius fracture according to the principles of AO, in case of instability of the ulna head, transfixation of the DRUJ (with Kirschner wire or position screw)

Fractures of both forearm bones

Simultaneous fractures of both bones often occur as a high-energy trauma. Assessment of the condition of soft tissue open fracture is important. 

The clinical picture tends to be typical due to the instability and deformity of the forearm and it is quite stressful for the patient.

●      Treatment

○      Surgical - all dislocated fractures (most) closed and open. Osteosynthesis according to AO principles

■      splint osteosynthesis is the standard

■      intramedullary fusion - little used because of limited stability

■      external fixation - especially for acute stabilisation in open fractures

●       Note: Osteosynthesis must restore the length of both bones and provide rotational stability of the radius.

○      Conservative - rarely - only considered for non-dislocated fractures or when surgery must be primarily delayed - comorbidities, polytrauma. Fixation with a high cast for 6-8 weeks.

Complications of diaphyseal fractures

Treatment of diaphyseal fractures of the forearm is often burdened with complications.  These are observed in both conservative and surgical treatment. The relatively higher rate of complications is partially caused by the longer bone healing time in this location (the cortical type of bone requires longer healing time than the spongious type) and partially caused by the higher demands on stability during the bone healing period - especially in rotations.  Complications include:

●       Prolonged healing or malunion (pseudoarthrosis) in case of instability or failure of healing.

●       Failure of osteosynthesis - loosening of material and subsequent dislocation of fragments

●       Rotational malposition

●       Ossification of the interosseous membrane

●       Neurovascular injury (n.radialis)

●       Restriction of mobility - pronation / supination , restriction of mobility in the wrist

Fractures of the distal radius

This is the most common fracture of the upper limb skeleton and one of the most common fractures in surgical practice.

The most common injury mechanism of this fracture is a fall on an outstretched upper extremity.  Another important aspect is the position of the wrist at the time of impact (volar or dorsal flexion).

This typically concerns older patients, predominantly women over 60-65 years of age, as a low-energy injury (simple fall) in the osteoporosis field.

A second peak of the virtual incidence curve is then seen in younger patients (adolescents, young adults). In this category, on the other hand, the high-energy mechanism predominates (traffic accidents, sports, etc.) and fractures tend to be more complex (comminuted fractures, concomitant ligamentous injuries of the carpus, etc.).

Diagnosis tends to be clinical in typical fractures with dorsal angulation - bayonet deformity of the distal forearm.  As mentioned in the introduction, we must not neglect a thorough assessment of blood supply and tenderness - especially fractures with volar angulation (e.g. modo Smith) may be accompanied by a lesion of the nervus medianus.

Furthermore, in most cases, an X-ray in 2 projections (AP and lateral) is sufficient to establish the diagnosis. In case of ambiguity or in intra-articular comminuted fractures, we add the CT scan with the possibility of 3D reconstruction.

To classify distal radius fractures we can use complex classifications - AO, Frykman or Fernandez classification.

In clinical practice, however, descriptive anatomical classification according to the X-ray image (intra-articular, extra-articular, simple, comminuted fracture...) is used more often, or, in case of typical fractures, (Colles, Smith) eponyms are used.

Typical simple extraarticular fractures include Colles fracture - with dorsal inclination of the articular surface, and Smith fracture - with volar dislocation of the distal fragment.

●      Treatment:

○      Conservative - due to the high incidence of fractures in elderly polymorbid patients, a non-surgical treatment plays an important role. 

■      repositioning under loc. anesthesia (10 ml of 1% Mesocaine in the fracture)

■      repositioning table - traction by the thumb and 2nd and possibly 3rd finger in ulnar duction

■      counter traction 5 kg, leave for 5-10 minutes

■      closed reposition and alignment of the angulation,

■      fixation with a circular padded plaster cast - cut in the acute phase (during plastering)

■      X-ray check-up

■      first check on the second day - check for blood flow

■      replacement of the plaster cast and an X-ray check-up in one week (possibility of secondary dislocation when the swelling subsides and resorption in the fracture area)

■      total fixation time 4-6 weeks depending on the nature of the fracture

■      removal of fixation and rehabilitation care

●       CAVE: potentially unstable fractures may redislocate after 2-3 weeks, therefore monitoring of the follow-up X-rays is necessary !

○      Surgical

■      Indications - fractures that cannot be satisfactorily reduced and fragments secured in plaster fixation, fractures that are obviously unstable - X-Ray signs of instability include:

●      initial dorsal angulation > 20° or volar angulation

●      significant comminution of the dorsal cortex

●      intra-articular fracture + distal ulna fracture

●      significant osteoporosis

●      need for extreme wrist positioning in the cast fixation for fragment retention

■      Osteosynthesis options

●      angle-stable splints - most commonly used (volar splint)

●      tension screw

●      external fixateur - possibly supplemented with Kirschner wires

●      intramedullar osteosynthesis - special nail (less frequently)

●      percutaneous mini-osteosynthesis with Kirschner wires - usually as an adaptive mini-osteosynthesis with the need for plaster fixation  

Luxation of the wrist

This is a complex injury to bone and ligamentous structures.  According to the relative position of the radius and the os lunatum, the injuries are divided into:

Perilunate luxation - lunatum remains in its position, the rest of the carpus is dislocated dorsally, often associated with fracture of the carpal bones (os scaphoideum, capitatum, triquetrum) or proc. styloideus radii

Luxation of lunata - lunatum dislocated ventrally, the rest of the carpus not dislocated

●       DIagnostics

○       X-ray - especially the lateral projection, CT scan - more accurate detection of fracture lines and position of bones and fragments.

●       Treatment - acute closed repositioning and subsequent surgical revision with suturing of injured ligaments, transfixation with K-wires, cast fixation for 6-8 weeks, followed by intensive rehabilitation

Carpal bone fractures

Scaphoid fractures

The most commonly injured bone of the wrist, approximately 70% of fractures are in the middle third, 20% in prox. pole and 10% in the dist. third.

The most common mechanism of occurrence is a fall on an extended upper extremity, often in younger patients as a sports injury, car accidents (motorcycle accidents)

The vascular supply to the os scaphoideum runs from the distal pole proximally (retrograde), which is important in terms of fracture healing, resp. the relatively frequent risk of complications (avascular necrosis, prolonged healing to non-healing - malunion) 

●       DIagnostics

○       clinical - palp. painfulness of the foveola radialis (fossa la tabatière)

○       X-ray projection - AP, lateral, semi-pronation 45°

■       in case of a positive clinical and neg. X-ray, a plaster fixation and a follow-up clinical examination and repeated X-ray in 14 days are recommended

○       CT scan - negative result is conclusive after 14 days after injury, specification of fracture type - Herbert classification

○       (MRI - negative result is conclusive after 4 days from injury)

●       Treatment

○       Conservative - stable fractures of the middle and distal third (Herbert A)

■       Plaster fixation 8 - 12 weeks!, type and time depending on fracture type and healing:

●       for stable fractures - 8 weeks below the elbow

●       for unstable fractures without surgery - 12 weeks - first 6T high cast (1st - 2nd finger - arm)

●       X-ray check-ups

○       Osteosynthesis 

■       indications - unstable fractures (Herbert B), stable fractures - faster return to activity, malunion

■       Herbert screw - allows compression of the fracture using two threads with unequal pitch

■       Spongioplasty + osteosynthesis - problem of malunion

Fractures of other carpal bones

Most commonly, fractures of the os triquetrum and os trapezium - often as abruptions (abruptions of the posterior edge of the triquetrum - breaking off of the edge with the ligament tendon, usually without significant dislocation)

Os trapezoideum rarely

May be isolated or part of a complex wrist injury

●       Treatment

○       Most often conservative, fixation 4-6 weeks 

○       surgical treatment in case of unstable fractures and complex injuries

Fractures of the metacarpals

These are very common fractures.  Frequent mechanism of injury for this fracture is a direct blow with a fist, pinching the hand, or indirectly - falls during sports.

Metacarpals are tubular bones in which we anatomically distinguish the base, diaphysis, collum and head.  In this case, similarly to cases involving fractures of long bones, we encounter intra-articular, extra-articular and diaphyseal fractures.  The fractures may be simple (lateral, oblique, spiral), interfragmentary or comminuted.

Because of the important function of the hand, healing in malposition can be disabling - watch out especially for the rotational deviation (dislocation ad peripheriam), in which malposition results in deviation and crossing of the fingers.

When immobilizing the wrist and fingers, it is important to follow the principles of physiological positioning

to prevent contractures and rotational deviation:

○      wrist in 20-40° dorsiflexion

○      MCP joints in 80-90° flexion

○      IP joints in extension

Typical metacarpal fractures include the following:

●      Boxer fracture - subcapital fracture of V. MTC with palmar angulation of the dist. fragment

●      Bennett's fracture - two-part intra-articular fracture of the base of the first MTC with luxation or subluxation of the carpometacarpal joint

●      Rolando fracture - three-part intra-articular fracture ("Y shape") of the base of the first MTC

●      Treatment

○      Conservative - stable closed fractures

■      repositioning and cast fixation - usually 3-5 weeks, then functional rehabilitation

■      for fractures requiring fixation of the first metacarpal, we fix this fracture in the abduction position

○      Surgical - stable osteosynthesis, early mobilisation

■      angle-stable splints

■      compression screws

■      intra-medullar stabilisation

■      external fixation

Finger fractures

The shape of the proximal and middle links is similar to that of the metacarpals; the distal phalanx is terminated by a nail roughening (apex). The MP and IP joints are reinforced laterally with collateral ligaments.

●      Diagnostics: clinical, X-ray in two projections

●      Treatment:

○      conservative - plaster fixation for 3-5 weeks

■      physiological position in plaster fixation - prevention of contractures and rotational deviation

○      surgical: K. wires, tension screws, angle-stable splints, external fixateur + early rhb

●      Complications

          - no treatment - deformities,       

          - excessive fixation - stiffness,

          - wrong treatment - deformity + stiffness

Luxation of fingers

MCP joints luxation

relatively rare (most often dorsal luxation of the 2nd or 5th finger)

Injury of the palmar disc (may form interpositus)

fixation in 60-75° flexion

Luxation of PIP/DIP joints

typical sports injuries

mostly dorsal (volar, lateral)

collateral ligament injuries

Always use X-ray diagnosis to rule out fracture!

●      Treatment

○      luxation - repositioning + immobilization 1-4 weeks (depending on the type of luxation)

○      luxation fracture - repositioning + Ki-wire 3-4 weeks

BIBLIOGRAPHY:

Zeman M, Krška Z. Speciální chirurgie. 3., dopl.přeprac. vyd. Praha: Galén; 2014. 511 s.

Pokorný V. Traumatologie. Vyd. 1. Praha: Triton; 2002. 307 s.

Wendsche P, Veselý R. Traumatologie. Druhé, přepracované a rozšířené vydání. Praha: Galén; 2019. 371 s.

https://aotrauma.aofoundation.org/education