Surgical Anatomy. — The region of the wrist is compact and contains numerous tendons, nerves and vessels in close relation with the radius, ulna and carpus. The normal relations of these structures and the surface landmarks should be known before one is qualified to recognize and fully appreciate the deformities accompanying fractures of the lower end of the radius. Variations within normal limits are common in the lower ends of the radius and ulna, and the carpus is frequently the seat of pronounced anomalies. It is necessary, therefore, that the opposite wrist be examined carefully before determining the conditions present in the injured member. The styloid process of the radius normally occupies a lower level than the ulnar styloid. Nearly all fractures of the lower end of the radius are accompanied by an elevation of the radial styloid; this condition is determined by comparing the relative levels of the two styloid processes as shown in Fig. 376. The uninjured wrist is used as the standard of comparison in ascertaining the distance the radial styloid has been raised. On the anterior surface of the wrist wall be noted two eminences. To the radial side is the thenar eminence; the upper margin of which is at a slightly lower level than the corresponding margin of the hypothenar eminence which is situated at the ulnar side of the wrist. When the outer side of the forearm is shortened by fracture of the radius the thenar eminence is raised according to the extent of the deformity. The outer aspect of the lower end of the radius is the only portion of the bone which is strictly subcutaneous, yet the lower half of the radius may be palpated without difficulty since there is little else than tendons interposed between the skin and the bone. On the posterior surface of the lower expanded quadrilateral extremity of the radius are a number of vertical grooves for the accommodation of the extensor tendons passing from the forearm to the hand. At about the middle of this surface will be noted a prominent ridge which forms the outer margin of the groove for the passage of the extensor longus pollicis. The tendons of the extensor ossis metacarpi pollicis and extensor brevis pollicis pass to the outer side of the radius, obliquely across the base of the styloid process. The flexor tendons, radial artery, and median nerve pass in front of the lower end of the bone. The radial nerve as it courses down the outer side of the forearm and under the tendon of the supinator longus is sometimes injured and may give rise to considerable pain during the after-treatment. The inner aspect of the lower end of the radius presents the 'sigmoid cavity' for articulation with the head of the ulna; just beneath the lower margin of this surface is attached the base of the triangular fibro-cartilage, which binds the radius and ulna together. With the forearm semipronated the ulnar styloid may be palpated as a prominence of bone which is continuous with the posterior subcutaneous border of the ulna. The tip of the process is on a level with the articulation of the wrist. When the forearm is carried into complete pronation the ulnar head, instead of the styloid process, presents beneath the skin. The inferior surface of the lower end of the radius articulates with the upper row of carpal bones and looks downward and slightly forward. The internal structure of the lower end of the radius should be studied to fully appreciate the mechanism of fractures of this region. A short distance above the lower end of the bone the surface layer of compact tissue changes rapidly into the heavy tube of compact bone which forms the shaft of the radius, and it is here that fracture most often occurs. It is not uncommon to find the end of the upper fragment driven into the lower fragment, which means a more or less extensive crushing and comminution of the cancellous tissue in the lower end of the radius, and accounts to some extent for the tendency to recurrence of deformity following reduction. Thus, when the lower fragment is pulled back into position following impaction, there is a wedge-shaped space in the lower fragment corresponding to the crushed cancellous tissue, and 'unless the layer of compact bone on the posterior aspect of the lower fragment is firmly engaged the deformity will return when the parts are released. A consideration of the internal structure of the lower end of the radius as shown in Figs. 268 and 384 will explain this tendency to recurrence of deformity, and the necessity for overcorrecting the displacement so that the dorsal layer of compact tissue may properly engage the upper fragment.<Callout type="important" title="Important">Overcorrection is crucial to prevent recurrence of deformity.</Callout> Fig. 340. — Fracture of lower end of radius produced by 'auto-kick.' Fractures in this region of the skeleton show considerable variation, but the overwhelming majority corresponds more or less closely to the type described by Colles. His original description in 1814 was of a fracture one and a half inches above the articular surface, but subsequent experience has shown that the usual break is within three-fourths of an inch of the lower end of the bone. At the present time, therefore, Colles' name is used to indicate a condition slightly different from the one originally described by him.<Callout type="tip" title="Tip">Colles' fractures are common and typically occur near the wrist joint.</Callout> The typical Colles' fracture is transverse or oblique, does not enter the articular surface and is accompanied by a backward displacement of the lower fragment. This backward displacement of the distal fragment produces the typical 'silver-fork' deformity which is so characteristic of Colles' fracture (see Figs. 354 to 367). The nature of the deformity varies somewhat with the line of fracture (see 'Symptoms,' page 252). The usual Colles' fracture is the result of a fall on the outstretched hand. If the fall is sustained on the palm of the hand, as is usual, the distal fragment is displaced backward and the typical Colles' fracture is the result. If impaction is present it is the cancellous tissue near the posterior surface of the lower fragment which suffers most. In rare instances the distal fragment may be displaced ventrally and the condition is then spoken of as a 'reversed Colles' fracture.' This type of deformity is usually produced when the causative trauma is received on the dorsal aspect of the hand with the wrist in flexion.<Callout type="warning" title="Warning">Ventral displacement can lead to severe complications.</Callout> An oblique fracture passing from the posterior surface of the lower end of the radius into the articular surface, with dorsal displacement of the fragment, is known as Barton's fracture. When the break enters the articular surface from the anterior aspect of the lower end of the radius, with ventral displacement of the fragment, the condition is spoken of as a 'reversed Barton's fracture.' This terminology is rather unfortunate since these two conditions are in reality luxations of the wrist complicated by fracture of the lower end of the radius. Thus Barton's fracture is a backward luxation with fracture of the posterior lip of the radius, while reversed Barton's fracture is an anterior luxation with fracture of the anterior lip of the radius.<Callout type="risk" title="Risk">Barton and reversed Barton fractures can be life-threatening if not treated properly.</Callout> The lower epiphysis of the radius is ossified by a single center which makes its appearance about the end of the second year. The epiphyseal cartilage is obliterated during the twentieth year. The causes of epiphyseal separations are similar to those producing Colles' fracture, and the deformity usually consists in a backward displacement of the lower fragment. It is not uncommon to find epiphyseal separations of the lower end of the radius complicated by fracture; examples of this condition are shown in Figs. 348 to 353.<Callout type="important" title="Important">Epiphyseal separations can complicate Colles' fractures.</Callout> Symptoms. — The patient almost invariably gives a history of having fallen on the outstretched hand. The injury is followed immediately by severe pain and loss of function, and the sufferer presents himself for treatment and relief. The attitude is usually characteristic. He stands with the shoulders slightly forward and the forearms held horizontally across the body. The injured member is supported by the opposite hand and there is considerable anxiety in both attitude and gait lest the injured wrist be disturbed. The onset of swelling about the wrist is prompt and sometimes pronounced, and, unless the case is seen immediately following the accident, the deformity is to some extent masked.<Callout type="tip" title="Tip">Look for characteristic posture when suspecting a Colles' fracture.</Callout> Fig. 354. — Typical Colles' fracture a few minutes following the accident. Fracture transverse and impaction present. Compare this deformity with the other Colles' fractures shown in this chapter and with the backward dislocation shown in Fig. 378.<Callout type="important" title="Important">Immediate imaging is crucial for accurate diagnosis.</Callout> The radial styloid is usually raised above its normal level, though in many instances the displacement is not marked enough to bring the tip of the process above the level of the end of the ulnar styloid. (See Figs. 376 and 377.) In a transverse Colles' fracture with impaction there is generally rotation and angular deformity as well as backward displacement of the lower fragment.<Callout type="warning" title="Warning">Impacted fractures can be difficult to treat without proper equipment.</Callout> Crepitus is easily detected in unimpacted cases. In impacted cases crepitus will be absent until the impaction has been broken up. In more than half of the cases of Colles' fracture the condition is complicated by rupture of the triangular fibro-cartilage or an equivalent avulsion of its ulnar attachment so that the head of the ulna and the lower radial fragment are separated and the wrist broadened.<Callout type="important" title="Important">Rupture of the triangular fibro-cartilage can lead to broader wrists.</Callout> Fracture of the ulnar styloid, so commonly seen in Rontgenograms of Colles' fracture, is an evidence of the action of this ligament. The lower end of the ulna is, as a rule, displaced forward as well as inward, and the absence of the prominent ulnar head from the dorsum of the wrist is noticeable.<Callout type="risk" title="Risk">Displaced ulna can cause additional pain and complications.</Callout> In the usual Colles' fracture the hand is inclined slightly to the radial side and the base of the thenar eminence is higher than normal. This radial displacement is sometimes pronounced, as shown in Figs. 356 and 364.<Callout type="tip" title="Tip">Radial displacement can be a key indicator.</Callout> In fractures showing extensive comminution of the lower end of the radius the deformity is often not characteristic and the condition may be compound. When the fracture is produced by an auto-crank kick the displacement is often slight and the break is usually transverse.<Callout type="important" title="Important">Auto-kick fractures can have minimal displacement.</Callout> A Colles' fracture without deformity is sometimes seen, though the condition is extremely rare. Even when the deformity is slight, it is as a rule characteristic. In oblique Colles' fractures the ventral deformity is more pronounced and lower than in the transverse type.<Callout type="important" title="Important">Oblique fractures can have different characteristics.</Callout> When the break is oblique the plane of the fracture is usually similar to that shown in
Key Takeaways
- Recognize the characteristic deformities and symptoms of Colles' fractures.
- Understand the importance of overcorrection to prevent recurrence of deformity.
- Be aware of complications like displaced ulna or rupture of triangular fibro-cartilage.
Practical Tips
- Always compare the injured wrist with the uninjured one for accurate diagnosis.
- Use X-rays to confirm the presence and extent of fractures, especially in impacted cases.
- Apply proper immobilization techniques to prevent further displacement during treatment.
Warnings & Risks
- Be cautious when treating displaced ulna as it can cause additional pain and complications.
- Avoid undercorrection which can lead to recurrence of deformity.
- Do not ignore the possibility of epiphyseal separations in children or adolescents.
Modern Application
While the techniques described in this chapter are historical, the principles of recognizing and treating fractures remain relevant. Modern imaging technology has improved diagnostic accuracy, but the importance of proper immobilization and early intervention remains critical for effective recovery.
Frequently Asked Questions
Q: What is a Colles' fracture?
A Colles' fracture is a break in the lower end of the radius bone that typically occurs near the wrist joint. It often results from falling on an outstretched hand and causes a 'silver-fork' deformity.
Q: How can I tell if someone has a Colles' fracture?
Look for characteristic symptoms such as pain, loss of function in the hand and wrist, swelling around the wrist, and a tendency to hold the arm horizontally across the body. The injured member is often supported by the opposite hand.
Q: What are the complications of Colles' fractures?
Complications can include displacement of the ulna, rupture of the triangular fibro-cartilage, or extensive comminution of the radius bone. These can lead to broader wrists and additional pain during recovery.