The Treatment of Closed Finger and Metacarpal Fractures

Abstract

Background

Fractures of the fingers and metacarpal bones are the most common fracture type in the upper limb, with an incidence of 114 to 1483 per 100 000 persons per year. The clinical importance of closed finger and metacarpal fractures is often underestimated; inadequate diagnostic and therapeutic measures may result in serious harm. This review concerns the basic elements of the diagnosis and treatment of finger and metacarpal fractures.

Methods

This review of the incidence, diagnosis and treatment of finger and metacarpal fractures is based on pertinent publications retrieved by a selective search of the literature.

Results

The main focus of treatment lies on restoration of hand function in consideration of the requirements of the individual patient. The currently available evidence provides little guidance to optimal treatment (level II evidence). Although most closed fractures can be managed conservatively, individualized surgical treatment is advisable in comminuted fractures and fractures with a relevant degree of torsional malposition, axis deviation, or shortening, as well as in intra-articular fractures. Minimally invasive techniques are, in principle, to be performed wherever possible, yet open surgery is sometimes needed because of fracture morphology. Postsurgical complication rates are in the range of 32–36%, with joint fusion accounting for 67–76% of the complications. 15% involve delayed fracture healing and pseudarthrosis.

Conclusion

Individualized treatment for finger and metacarpal fractures can improve patients’ outcomes, with major socio-economic and societal benefits. Further high-quality studies evaluating the relative merits of the available treatments are needed as a guide to optimized therapy.

cme plus

This article has been certified by the North Rhine Academy for Continuing Medical Education. Participation in the CME certification program is possible only over the internet: cme.aerzteblatt.de. The deadline for submission is 14 December 2024.

With its highly specialized precision pinch and power grip, its opposing thumb, and tactile organ function – the only tactile organ that can be brought to the object – the hand serves as an essential instrument for perceiving and making contact with its immediate surroundings (1).

Whereas fracture of the distal radius is one of the most common injuries, with an incidence of 73 to 202 per 100 000 in men and 309 to 767 per 100 000 in women, the number of inpatients in Germany with a diagnosis of “metacarpal fracture” or “finger fracture” recorded in 2021 by the Federal Statistics Office was, in each case, below one percent of all fractures (2–7). Given the fact that these injuries can be treated on an outpatient basis, however, the true incidence overall is significantly higher, resulting in a general underestimation of frequency (5). On the other hand, with an incidence of 114 to 1483 per 100 000 population, fractures of the fingers and metacarpals are the most common fractures of the upper limbs and account for up to ten percent of all fractures (Tables 1 and 2) (8–15). Furthermore, finger fractures represent up to one quarter of all missed fractures (1).

Table 1. Incidences of metacarpal and finger fractures.

Diagnosis	Sex	Total inpatients	Inpatients <60 years	Inpatients >60 years
Fractures of the metacarpals		7143 (0.042%)*1	5153	1990
Fracture of first metacarpal bone (S62.2)	m	853	663	190
	f	306	123	183
Fracture of other metacarpal bone (S62.3)	m	4028	3368	660
	f	1676	802	874
Multiple fractures of the metacarpal bones (S62.4)	m	202	173	29
	f	78	24	54
Fractures of the fingers		9045 (0.053%)*2	6366	2679
Fracture of thumb (S62.5)	m	1217	825	392
	f	346	181	165
Fracture of other finger (S62.6)	m	5298	4037	1261
	f	2138	1303	835
Multiple fractures of the fingers (S62.7)	m	32	15	17
	f	14	5	9

*¹ Inpatients discharged in Germany with primary diagnosis S62.2–7 (2021)

*² Proportion of all fractures

Table 2. Comparison of international incidences of fractures of the metacarpals and fingers (8–13).

Author	Country	Period	Age	Incidence hand fractures without wrist, incl. fingers	Incidence metacarpal fractures S62.2, S62.3, S62.4	Incidence finger fractures S62.5, S62.6, S62.7
Bergh et al. (8)	Sweden	2015–2018	≥ 16 years	158.9/100 000 (MCs+fingers)	88.8/100 000	70.1/100 000
Giustini et al. (9)	Italy	2011	all age groups	1483/100 000	260/100 000	232/100 000
Dominguez-Prado et al. (10)	Spain	2016–2018	≥ 16 years	1232 cases
Beerekamp et al. (11)	Netherlands	2012	≥ 16 years	310/100 000
M Gordon et al. (12)	USA	2009–2018	all age groups	714/100 000		450/100 000
Wenzinger et al. (13)	USA	2010	≥ 18 years	351 096 cases		240 913 cases

The present review article addresses the fundamental principles of diagnostics and treatment of finger and metacarpal fractures, the knowledge of which is essential to non-hand surgery colleagues in particular, given the relevant frequency and possibility of outpatient management of these injuries. So, the primary aim of this article is to distinguish between patients who can be managed conservatively in an interdisciplinary setting and those who require surgical treatment.

Methods

A selective search of the literature was conducted and included the most relevant and high-quality studies (Table 3). In order to assess incidence, a second selective literature search was performed and requests were made with the Central Institute for Statutory Health Insurance in Germany and the German Social Accident Insurance (Tables 1 and 2). A detailed presentation of the literature searches can be found in the eMethods (eMethods, eFigures 1 and 2).

Table 3. Meta-analyses and randomized controlled studies on the treatment of finger and metacarpal fractures (23–27).

	First author (year)	Study design	Intervention	Outcome/primary end point*	Comments
1	Melamed et al. (2017) (23)	Meta-analysis with 4 RCTs and one retrospective review with 222 pats., ø follow-up: 7.5 months	MPIF versus KWIF for unstable metacarpal fractures	TAM: KWIF higher than MPIF (RR 1.15, [1.03; 1.29], p = 0.017; heterogeneity p-value = 0.44) Percentage movement in comparison with the contralateral hand: KWIF 12% more in comparison with MPIF [0.06; 0.17], p <0.001, heterogeneity p-value = 0.01)	Complication rate/grip strength no significant difference
2	Peyronson et al. (2023) (24)	RCT of 42 pats.; follow-up: 1 year	Non-operative versus operative treatment of oblique/spiral MSF	Grip strength in comparison with contralateral hand 104% ([89; 120] in the non-operative group and 96% [89; 103] in the operative group (p = 0.34)	1 minor complication in the non-operative group; 4 minor complications and 3 revisions in the operative group
3	Zong et al. (2016) (25)	Meta-analysis of 6 RCTs with a total of 288 pats.	Conservative versus intramedullary nailing versus transverse pinning with K-wires versus MPIF for fractures of the fifth metacarpal	Higher total complication rate for intramedullary nailing versus conservative treatment (OR 0.32; [0.13; 0.79]	No significant difference to the other treatment methods
4	Pellatt et al. (2019) (26)	RCT with 97 pats. ø follow-up: 12 weeks	Buddy taping versus plaster casting for uncomplicated fifth metacarpal neck fractures	12 weeks after intervention equivalent quickDASH scores in both groups (buddy 0, interquartile range [IQR] 0 to 2.3; plaster 0, IQR 0 to 4; difference 0; [of the difference 0; 0])	Comparison of two conservative treatments
5	El-Saeed et al. (2019) (27)	RCT with 40 pats.; ø follow-up: 7 months	MPIF versus KWIF for unstable MSF	TAM: MPIF (249.2) higher than KWIF (217.8), p <0.05; shorter mean operating time of the kwif group (41.25 min) in comparison with the mpif group (77.2 min) lower complication rate in the mpif group (2/20) than (5/20) in the kwif group	Start of active motion after 1 week for MPIF and after four weeks for KWIF

IQR, interquartile range; KWIF, K-wire internal fixation; MPIF, mini-plate internal fixation; MSF, metacarpal shaft fracture; pats., patients; RCT, randomized controlled trial; TAM, total active motion

*The 95% confidence intervals are provided in square brackets.

eSupplement.

Metacarpal fractures

General

The metacarpal bones have a fan-shaped arrangement (e22). Whereas the fourth and fifth carpometacarpal joints are mobile (20 to 40 degrees), the second and third are almost immovable (three to eight degrees) (e12).

Special diagnostic features

The loss of knuckle contour is usually due to fracture-related shortening, while the proximal prominence arises from a dorsal axial deviation, usually caused by intrinsic muscle pull. The extension deficit is due to loss of tension of the extensor tendon apparatus. The more ulnarward the fracture, the more clinically apparent do fracture-related shortenings become because the central intermetacarpal ligamentum prevents shortening of more than three to four millimeters (20, 32, e22).

The second and third MCs can be assessed by radiography, ideally on a semi-pronation view, and the fourth and fifth MCs on a semi-supination view, in addition to the dorsopalmar metacarpal projection. A Brewerton view is suitable for evaluating the metacarpal heads, with the dorsum of the fingers placed flat on the cassette, the elbow in extension, the wrist in neutral position, and 65-degree flexion of the MCP joints (32).

Conservative treatment is thus possible for metacarpal neck fractures with a dorsal axial deviation of up to 40 to 50 degrees for the little finger, 30 degrees for the ring, 20 degrees for the middle, and 15 degrees for the index finger. The tolerance for shaft fractures is significantly lower, reported as ten degrees for the index and middle fingers and 20 to 30 degrees for ring and little fingers (32).

Fractures of the thumb

General

Unlike fractures of the second to fifth MCs, extra-articular fractures of the first MC also tolerate mild rotational deformity or an inclination in the frontal and sagittal planes due to the compensatory effects of the neighboring joints (e15).

Fractures of the distal phalanx of the thumb

The etiology of these fractures is usually associated with occupational accidents and, as such, often present as open fractures with joint involvement. Dorsal proximal base fractures of the terminal phalanx are rare in the thumb and are only treated surgically when there is significant displacement or a step-off (33).

Fractures of the first metacarpal

In the majority of cases, fractures of the first MC are found in the proximal third and are classified as extra-articular “Winterstein” fractures and intra-articular “Bennett” and “Rolando” fractures. Winterstein fractures account for 57 percent of fractures of the first MC, while Bennett fractures constitute 34 percent and Rolando fractures 9 percent of fractures (e13, e14). Common to all types of fracture is the axial compression of the first MC against the trapezium with flexion of the carpometacarpal joint (1, 33). Etiologically, in addition to axial compression, the fracture is often also associated with subsequent dislocation from the traction forces of the abductor pollicis longus (APL) tendon and flexion of the thenar muscles (1, 33).

Extra-articular Winterstein fractures demonstrate dorsal angulation at the base of the first MC as a result of traction of the APL, while at the same time the distal shaft fragment is flexed by traction of the thenar muscles. A Winterstein fracture often requires surgical management, especially in the presence of a larger comminution zone and despite its extra-articular character (1, 33, e15).

A Bennett fractur refers to a palmar, intra-articular fracture at the base of the first MC. This results in radiodorsal displacement of the base, while ligaments stabilize the ulnopalmar fragment (Bennett fragment) in its anatomical position. The classic dorsoradial subluxation of the carpometacarpal joint is the result of traction by the abductor pollicis longus and extensor pollicis longus and brevis muscles. Therapy usually involves closed, open, or arthroscopically assisted reduction, followed by wire or screw fracture fixation.

With increased axial force on the flexed thumb, an additional fracture of the dorsal joint surface may occur with development of a Y or T-shaped fracture, known as a Rolando fracture. Given the displacement, there is an indication for surgery here too, usually by locking plate fixation.

After surgery and depending on the type of fracture fixation, additional immobilization of the thumb with free movement of the interphalangeal joint should be considered (1, 33, e15).

eFigure 1.

Flow diagram demonstrating the approach for a selective literature search for treatment of finger and metacarpal fractures

MC, metacarpal

eFigure 2.

Flow diagram demonstrating the approach for a selective literature search for international incidences of finger and metacarpal fractures

Basic anatomical principles

The 27 bones of the hand are divided into three groups: carpal bones, metacarpals (MCs), and phalanges. The metacarpophalangeal (MCP) joints allow flexion and extension of the fingers as well as some degree of abduction and adduction. While the three phalanges of the fingers are connected by the proximal and distal interphalangeal (PIP, DIP) joints, the two phalanges of the thumb are connected to the first metacarpal by the thumb metacarpophalangeal joint and to each other by the interphalangeal joint. The thumb enjoys a special position in the hand and is thus different from the fingers. However, for simplicity’s sake, it is dealt with in this manuscript together with the fingers (1). Each digit is primarily supplied by two (radial and ulnar) palmar neurovascular bundles (16).

Functionally, the fingers diverge when extended, whereas when their joints are flexed to make a fist, rotation of the phalangeal joints makes them converge parallel to one another, without crossing over, and point towards the scaphoid (Figures 1 and 2) (1, 17–19). While rotational deformity has a dynamic component, torsional malalignment refers to a static situation.

Figure 1.

Biomechanics of finger flexion

a) When making a fist, rotation occurs mainly in the PIP joints in addition to flexion of the finger MCP, PIP, and DIP joints (19).

b) The rotation component is determined by the differences in form of the heads of the proximal phalanges (19).

With the kind permission of the illustrator Prof. Dr. med. Martin Langer

Figure 2.

Assessing for the presence of torsion by making a fist with both hands

a) With the axes marked on the middle phalanges, the fingertips are pointing towards the scaphoid and lunate.

b) Torsional malalignment is well recognizable in the ring finger, secondary, for example, to a displaced fracture of the proximal phalanx, compared with the “healthy” contralateral side. The crossing over of the two fingers is known as scissoring, shown here by the middle and ring fingers.

Diagnostic investigations

History, clinical examination, and radiography form the corner stone of the diagnostic workup (20). History includes not only the exact mechanism of the accident and the forces involved but should also take into account hand dominance and occupation/hobbies together with their required dexterity (17). The clinical examination should look for any swelling and hematoma as well as locate the site of pain (21). Hematoma color provides information about the time of the fracture. Examination of the hand is always performed by comparison with the contralateral side to gain adequate appreciation of any axial deviation, dysfunction, and deformity, especially torsion (Figure 2) (17, 20). Distal phalangeal fractures, in particular, with their small bony dimensions, can present less pain, hematoma formation, and axial deformity and so be easily missed and not taken seriously, which is why appropriate radiological diagnostics are essential (22). Radiographs in at least two projections (dorsopalmar, strict lateral, possibly with an additional oblique view) are obtained, while computed tomography (CT) scans should be conducted where there is any suspicion of joint involvement or for comminuted fractures (20). A thin-slice CT scan allows more exact assessment of fracture morphology and facilitates planning of access and choice of fracture fixation technique for surgical management.

Principles of treatment

Table 3 provides a summary of the most relevant clinical studies, based on a selective search of the literature (level II evidence) (Table 3) (23–27).

In principle, when treating a fracture, the question of the optimal form of fracture fixation should not be the primary consideration, but rather whether conservative or surgical management will achieve the best functional outcome (28, 29). Furthermore, emphasis should not be on treating radiological findings but rather always on treating the patient and their individual needs (28).

The general aim is to restore the original range of motion, strength, and dexterity. However, the main challenge is presented by the contradiction between immobilization required for fracture healing and mobilization to achieve relevant function. Non-operative treatment runs the risk of delayed bone union, joint stiffness from prolonged immobilization, and tendon adhesions. This typically happens when immobilization includes joints which are not necessarily involved (Box).

Box. Immobilization regimes for conservative fracture management of finger and metacarpal fractures.

• Finger fractures

  • Fractures of the distal phalanx: finger plaster splint with free PIP joint, on reduction of swelling, placement of a Stack splint with free PIP and MCP joints for a total of around four weeks

  • Fractures of the middle phalanx: finger cast with free MCP joint for around four weeks

  • Fractures of the proximal phalanx: intrinsic plus position with free PIP and DIP joints and free wrist, with the option of buddy strapping to the uninjured adjacent finger for guided mobilization, for a total duration of about four weeks (eMethods, eFigure 3)

• Metacarpal fractures

  • Metacarpal neck fractures: intrinsic plus position with free PIP and DIP joints and free wrist for around two weeks, then change to a metacarpal brace for a further two weeks

  • Proximal fractures and shaft fractures: metacarpal brace for around four weeks

• General points on conservative management

  • Regular clinical follow-up reviews should be conducted to avoid the development of joint stiffness and tendon adhesions. Radiological evidence of fracture consolidation usually appears delayed, so particular attention should be directed towards symptoms of pain (“X-ray lags behind bone healing”) (1).

DIP, distal interphalangeal; MCP, metacarpophalangeal; PIP, proximal interphalangeal

The surgical approach also entails risks such as local infections, neurovascular injury, functional loss due to soft-tissue adhesions, and the possible need for implant removal together with tenolysis and arthrolysis (20).

Surgical fracture treatment requires immediate post-operative mobilization because soft-tissue adhesions secondary to the open approach are more pronounced than after conservative treatment procedures (24, 25, 30, 31). Patients should also be informed about the risk of posttraumatic osteoarthritis (32). All therapeutic approaches therefore have the common aim of minimizing immobilization to a maximum of five to six weeks and ensuring early mobilization to restore function (3, 26, 33–35).

Selecting the appropriate therapeutic approach

While stable extra-articular and non-displaced/mildly displaced fractures can usually be treated non-operatively with special splints, there is an indication for surgical management for non-reducible and unstable fractures, multiple fractures, torsional malalignment, and fractures with displaced joint involvement and a marked comminution zone (20, 32). Fractures treated in the first instance by conservative management should also have radiographical follow-up within one week to detect secondary displacement and initiate appropriate treatment (32).

Conservative management

If conservative treatment is planned, fracture reduction may be required, that is to say, brought into largely anatomical alignment. Reduction can be achieved under local anesthesia (2, 17). A digital nerve block (ring block) of the corresponding nerves is placed for those finger fractures presenting further proximally (20). Alternatively, a distal hand block with infiltration of the major nerves of the hand (radial, ulnar, and median nerves) can be performed (36).

Splinting of finger fractures requires the so-called intrinsic-plus position with full extension of the interphalangeal joints together with 70 to 90-degree flexion of the MCP joints (Box). In this intrinsic plus position, the ligamentous structures around the joints are taut and therefore less susceptible to shortening (eMethods Section, eFigure 3) (17, 37). In addition, the recommended immobilization of the joints either side of the fracture together with application of the splint serves to prevent renewed displacement (17). While stable fractures of the fifth MC are splinted by buddy strapping to the ring finger, fractures of the base of the second to fourth MCs are immobilized with a wrist splint (Box) (26, 32, 38).

eFigure 3.

a, b) Metacarpal brace, including the metacarpophalangeal joints in 90 degrees of flexion and applied buddy loop, for example, for a stable fracture of the proximal phalanx. The proximal and distal interphalangeal joints are free and should be mobilized, as should the wrist.

Conservative measures for fractures of the distal phalanx involve retention with a DIP joint splint, without including the PIP and MCP joints, whereas fractures of the proximal phalanx of the thumb require inclusion of the wrist in the immobilization (33). Duration of retention is usually four weeks (17).

Surgical management

In principle, minimally invasive approaches are favored. If fracture morphology does not allow this, however, an open procedure is required. An overview of surgical techniques and illustrating radiographs is provided in the eMethods Section (eMethods, eTable and eFigures 4–8).

eTable. Fundamentals of the surgical management of phalangeal and metacarpal fractures*.

Fixation technique	Advantages	Disadvantages	Indications, special features
Kirschner (K-)wire fixation	• minimally invasive • soft-tissue sparing • low costs • placement as intramedullary splinting or extension block pinning (modified Ishiguro technique) possible	• bicortical insertion: risk of thermal bone necrosis • risk of tethering functional soft tissue • crossed wires: avoid crossing near the fracture line to prevent rotatory instability • not usually stable enough for exercising • additional cast immobilization is often required	• intramedullary insertion for metacarpal fractures • anterograde crossed insertion for a proximal fracture of a phalanx • retrograde crossed insertion for a distal fracture of a phalanx • extension block pinning (modified Ishiguro technique) for mallet finger fractures
Compression wire fixation	• double thread provides interfragmentary compression and interlocking	• insertion is technically difficult • avoid dorsopalmar insertion to protect flexor tendons	• percutaneous management of transverse fractures of the proximal and middle phalangeal shafts
Lag-screw fixation	• interfragmentary compression • stable for light exercises • open and minimally invasive insertion possible	• insertion is technically difficult	• longitudinal and spiral fractures of the fingers and metacarpals • hardware removal not usually required
Plate fixation including hook plate	• utmost stability • stable for light exercises • dorsal placement preferred as this spares soft-tissue more than palmar approach • lateral placement possible	• technically demanding • extensive soft-tissue dissection required, risk of tendon adhesions • implant removal often required	• fractures with large comminution zone • comminuted fractures • usually locking plate model
External fixator	• stable for light exercises • placement technically easy	• usually only temporary fracture fixation for bridging of infections and swellings	• open fractures with extensive soft-tissue injury • for bridging of comminuted fractures or severely damaged joints, extensive bone defects, and ongoing infections
Lister’s intraosseous wire loop	• dorsal soft-tissue spared • high torsion stability • stable for light exercises	• implant removal required	• open fractures • finger replantations • joint fusions
Intramedullary canulated headless screws as described by Pinal et al.	• periosteum remains intact • stable for light exercises	•surgical shortening of the fracture possible • implant removal difficult, if at all necessary • joint involvement • not always rotational stable	• unstable, transverse fractures of fingers and MCs
Dynamic distraction external fixator (Suzuki fixator) (eFigure 8)	• complete treatment of the fracture possible • application easy • distraction both adjustable and readjustable • exploits ligamentotaxis	• high degree of adherence required • risk of infection • implant removal required	• complex articular fractures

* modified after (20, 23, 24, 25, 27, e16–e21)

eFigure 4.

Extension block pinning (modified Ishiguro technique) for a dorsal shear fracture of the distal phalanx: Firstly, the distal phalanx is placed into flexion to “distalize” the extensor tendon avulsion fragment as much as possible. The fragment is then secured in place with a K-wire (left) The distal interphalangeal joint is then extended, bringing the fragments closer together. Temporary fusion of the distal interphalangeal joint is achieved with a second K-wire (right).

eFigure 8.

67-year-old patient with an intra-articular fracture of the middle phalanx of the ring finger with dorso-ulnar subluxation of the base of the fractured middle phalanx. Surgical management with a commercially avaiable dynamic distraction fixation device and additional K-wire fixation near the base of the middle phalanx.

From left to right: dorsopalmar and strictly lateral X-rays of the fracture before and after surgery.

Given the appropriate indication, closed fractures should be operated within a few days after injury or after failed conservative treatment. An upper arm or forearm tourniquet provides a bloodless operative field for a maximum of two hours and thus optimal surgical conditions, especially for open procedures (17).

The “wide awake local anesthesia no torniquet” (WALANT) technique is also enjoying increasing application, providing adequate analgesia and local vasoconstriction by the administration of local anesthetic plus epinephrine (20, 39). Motor function is maintained, allowing intraoperative assessment of function, and perioperative costs are reduced (20, 40).

There are many different surgical techniques available for treating fractures of the fingers and metacarpals: dynamic distraction with external fixators, intramedullary splinting or transfixation with Kirschner wires (K-wires), screw/plate fixation, and external fixators (17, 23, 25, 27, 32, 33, e1). While K-wires are associated with shorter surgery times and sometimes longer postoperative immobilization compared with screws or plates, no significant difference was found with respect to postoperative limitation of motion (e2). Plate and screw fixation, supported by edema prophylaxis by elevation and lymph drainage, are functionally stable for light exercises, while postoperative treatment of fractures stabilized by K-wire fixation often needs to be adapted during the first four weeks to avoid wire migration (30, 31). External fixation techniques are applied for comminuted fractures where no other forms of fracture fixation are possible. They may be temporary to allow concomitant soft-tissue injury to subside until definitive care (17).

Postoperative management

Whereas immobilization is required for bony healing and to minimize pain, early exercising reduces tendon adhesions and ligament contracture and thus ensures a better functional final outcome. Elevation of the involved limb, local cooling, and anti-inflammatory measures reduce postoperative swelling and are also useful for conservative fracture management. Careful and active mobilization of all joints not immobilized should be encouraged. Specialized hand therapy is recommended in particular for complicated fractures. This form of treatment is intended in the first instance for protective reasons but also ensures stability while measures to control pain and reduce swelling are conducted. Functionality of the hand is restored by passive, and then actively assisted, and finally active exercises (1, 17, 20).

Complications

Complication rates of between 32 and 36 percent develop after surgery for fractures of the fingers and metacarpals (32). In general, the most common complication is joint stiffness in 67 to 76 percent of cases (32, e3, e4). Delayed or absent bony consolidation of the fracture may be observed in 15 percent of cases, while infections develop in 0.5 percent of closed fractures after surgical management (e3, e5).

Impending extension and flexion deficit of the metacarpal phalangeal joints should also be looked for in metacarpal, phalangeal neck, and shaft fractures (32, e3). Torsion malalignment has already been highlighted (Figure 2).

A further serious complication is complex regional pain syndrome (CRPS) which develops in 0.2 to nine percent of cases after peripheral bone and joint injury and in one to 13 percent after surgery of the peripheral limb. Here in particular, surgery involving as less tissue trauma as possible, use of tissue-sparing and targeted reduction maneuvers, adequate analgesia, and early mobilization are all crucial for the prevention of complications (e6).

Fractures of the fingers and metacarpals also have a huge socio-economic impact on the healthcare system: A study from the Netherlands found that fractures of the hand and wrist were the most expensive fractures of the healthcare system with 740 million US dollars, of which 63 percent (470 million US dollars) involved fractures of the fingers and metacarpals (e7).

Special features of finger fractures

Subungual hematomas often develop after fractures of the distal phalanx and should be drained by trephination. The dorsal nail plate and palmar fibrous septa of the pulp usually provide stability to transverse fractures of the distal phalangeal shaft, rendering them suitable for conservative treatment (37).

Fractures of the dorsal base of the distal phalanx, also referred to as mallet fractures, are usually the result of a hyperextension injury with axial compression of the DIP joint (shear fracture), while a subcutaneous extensor tendon avulsion fracture (mallet finger) is caused by forced flexion. Surgical treatment has proven of value for larger fragments (more than 30 percent on the strictly lateral radiograph) and dislocation or subluxation of the DIP joint. Otherwise, conservative management by immobilization of the joint in extension with free PIP joint movement (for example, in a Stack splint) is sufficient (Box) (37). Despite adequate treatment of distal phalangeal fractures, complications do develop in 45 percent of cases treated by conservative management and in 53 percent of those treated by surgery. These include infection, joint incongruence, nail deformity, and implant failure. Regular follow-up is essential here (e8, e9).

Comminuted fractures, dislocation fractures, and oblique/spiral fractures carry a high risk of secondary displacement, not only from compression of the comminution zone but also from proximal traction by the intrinsic muscles. So, there is usually an indication for surgery here using, for example, screw or dorsal plate fixation (37, e10).

Specific features of metacarpal fractures

The eMethods Section contains details of specific hand surgery features relating to metacarpal and finger fractures. Metacarpal fractures account for around ten percent of all fractures in general and 18 to 44 percent of all fractures of the hand (32, e11). Whereas 88 percent of fractures involve the second to fifth MCs, the fifth MC is the most often affected and is also referred to as a boxer’s fracture, although this type of fracture is hardly encountered in professional boxers and is more likely to occur in non-sporting pugilists (21, e12).

Metacarpal fractures are classified by their location as fractures of the head, neck, shaft, and base, or based on fracture morphology into transverse, short or long oblique fractures, and comminuted fractures (21).

Specific diagnostic features

Clinical examination often reveals loss of knuckle contour and dorsal proximal prominence of the MC. This is compounded by the fact that fracture-related shortening of two millimeters can result in an extension deficit of seven degrees. Given that the MCP joint normally allows hyperextension of around 20 degrees, shortening by up to six millimeters is tolerated before a relevant extension lag is evident, which might prevent achieving neutral position (0 degrees of extension) (20, 21, 32).

Additional special radiographs are required to complete the general diagnostic workup. Thin-slice computed tomography has proven itself for diagnosing comminution zones or intra-articular involvement (20, 32).

Special indications

With metacarpal fractures, torsional malalignment in particular is fundamental to the treatment decision, as each degree of torsion of a metacarpal bone results in a five-degree rotation of the corresponding fingertip, which in turn produces scissoring of the figures of 1.5 cm when making a fist (Figure 2) (32). Therefore, even minimal torsional malalignment requires appropriate treatment (20). The severity of any dorsal axial deviation, of which 30 degrees already restricts grip strength of the hand, is relevant for therapeutic decision-making (21). Surgical treatment is recommended for associated fracture-related shortening by six millimeters and more, as there is no further compensation to be expected from the MCP joint here. Intra-articular fractures require surgical correction if there is a step-off of more than one millimeter, or if more than 25 percent of the joint surface is involved, in order to minimize joint deformity and subsequent osteoarthritis (32).

Fractures of the thumb

With its exposed position and marked mobility, the thumb is frequently susceptible to bony injury. Fractures of the thumb are divided into fractures of the distal phalanx, proximal phalanx, and first metacarpal. These are then further classified into base, shaft, and head fractures, with or without joint involvement (33).

While fractures of the distal phalanx of the thumb are rare and only require surgery in exceptional cases, fractures of the first metacarpal are more common in the form of an extra-articular Winterstein fracture and intra-articular Bennett or Rolando fracture. They usually require surgical treatment (1, 33, e15). Details regarding fractures of the thumb are to be found in the eSupplement.

Conclusions

In summary, there are no standardized international or national guidelines on the treatment of fractures of the fingers and metacarpals. There are only a few high-quality studies which are dedicated in particular to specific methods of managing unstable longitudinal and spiral fractures of the metacarpals. Overall, the available data is inadequate, which argues against the formulation of standardized treatment recommendations for the various fracture morphologies and individual treatment requirements for finger and metacarpal fractures.

An individual approach should therefore be discussed with the patient, based on the available treatment options.

eFigure 5.

Fifth metacarpal neck fracture (also known as a boxer’s fracture) in a 17-year-old, associated with significant palmar angulation of more than 50 degrees and rotational deformity of the little finger. Minimally invasive closed reduction and management with two intramedullary K-wires.

From left to right, dorsopalmar and oblique X-rays of the metacarpus before and after surgery

MC, metacarpal

eFigure 6.

13-year-old patient with fractures of the second to fourth MC shafts; anatomical reduction and screw fixation of the second MC and plate fixation of the third and fourth MCs.

MC, metacarpal

eFigure 7.

Dorsal shear fracture of the distal phalanx of the middle finger with still open growth plate. From left to right: Strictly lateral and dorsopalmar X-ray before and after fracture fixation with a dorsal hook plate as an alternative to extension block pinning (eFigure 4) to avoid transfixation of the growth plate.

Question on the article in issue 50/2023:

The Treatment of Closed Finger and Metacarpal Fractures

The submission deadline is 14 December 2024. Only one answer is possible per question.

Please select the answer that is most appropriate.

Question 1

Approximately what percentage of all fractures of the human skeleton do finger and metacarpal fractures account for?

1. 1–2%

2. 5%

3. 10%

4. 20%

5. 35%

Question 2

Whereas fingers diverge when extended, when making a fist they converge, parallel and without crossing over, to point towards which anatomical structure?

1. the distal ulna

2. the scaphoid

3. the triquetrum

4. the basal joint of the thumb

5. the pisiform

Question 3

Which statement applies to fractures of the distal phalanges?

1. They are often not taken seriously.

2. They are usually very painful.

3. They can be diagnosed without taking X-rays.

4. Deformity renders them immediately obvious.

5. They present with extensive hematoma formation.

Question 4

Which position is recommended in the text for splinting finger fractures?

1. the intrinsic sign position

2. the extrinsic U position

3. the inner plus position

4. the intrinsic plus position

5. the thumb index U position

Question 5

According to the information provided in the text, which of the following problems represents the most common complication associated with the post-operative management of fractures of the fingers and metacarpals?

1. joint stiffness

2. delayed union

3. infections

4. persistent pain

5. postoperative malalignment

Question 6

Which statement regarding radiological diagnostics is most likely to apply?

1. A radiograph taken in one plane is sufficient to diagnose a grossly displaced phalangeal fracture.

2. A routine radiograph taken in one plane is sufficient when the patient is in severe pain.

3. Radiographs obtained in at least two planes are imperative when fracture of a finger is suspected.

4. MRI is superior to CT for diagnosing phalangeal fractures.

5. A CT scan is not suitable for excluding joint involvement.

Question 7

Which fractures are referred to as mallet fractures?

1. Proximal fractures of the first metacarpal

2. Distal fractures of the first metacarpal

3. Double fracture of one of the metacarpals

4. Longitudinal fracture of the first metacarpal

5. Fractures of the dorsal base of the distal phalanx

Question 8

The fracture of which bone is also referred to as a boxer’s fracture?

1. Fracture of the fifth metacarpal

2. Fracture of the second metacarpal

3. Fracture of two metacarpals

4. Fracture of the metacarpophalangeal joint of the thumb

5. Fracture of the distal interphalangeal joint of the little finger

Question 9

Rotational deformity can occur after a metacarpal fracture, with subsequent finger deformity. In this context, which of the following statements is true?

1. Each degree of torsion of a metacarpal bone results in two degrees of torsion of the corresponding fingertip.

2. Each half degree of torsion of a metacarpal bone results in five degrees of torsion of the corresponding fingertip.

3. Each degree of torsion of a metacarpal bone results in five degrees of torsion of the corresponding fingertip.

4. Each degree of torsion of a metacarpal bone results in eight degrees of torsion of the corresponding fingertip.

5. Each degree of torsion of a metacarpal bone results in half a degree of torsion of the corresponding fingertip.

Question 10

Which of the following statements on conservative treatment does not comply with the recommendations in the article?

1. The DIP and PIP joints do not require immobilization for metacarpal neck fractures.

2. A finger plaster splint should be applied for middle phalangeal fractures with immobilization of the MCP joint.

3. Regular clinical follow-up reviews should be conducted to avoid development of joint stiffness and tendon adhesions.

4. Bone consolidation is only evident on radiographs with some delay, which is why symptoms of pain are decisive.

5. A metacarpal brace should be applied for approx. four weeks for proximal metacarpal fractures.