The Treatment of Closed Finger and Metacarpal Fractures.

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.

Review article

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, 3, 4, 5, 6, 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, 9, 10, 11, 12, 13, 14, 15). Furthermore, finger fractures represent up to one quarter of all missed fractures (1).

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) Fractures of the fingers m 202 173 29 f 78 9045 (0.053%)*2 246366 54 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

Author Country Period 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 etal. (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.

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).

First author (year) Study design Intervention Outcome/primary end point* 1 Melamedetal.(2017) (23) Meta-analysis with 4 RCTs and one retrospective review with 222 pats., 0 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 contra-lateral 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 contra-lateral hand 104% ([89; 120] in the non-operative group and96% [89; 103] in the operative group (p = 0.34) 1 minor complication in the non-operative grroup; 4 minor complications and 3 revisions in the operative group 3 Zongetal.(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 meta-carpal 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 Pellattetal. (2019) (26) RCT with 97 pats. 0 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.; 0 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

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, 18, 19). While rotational deformity has a dynamic component, torsional malalignment refers to a static situation.

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.

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, 24, 25, 26, 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).

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, 34, 35).

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).

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).

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).

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).

Fixation technique Advantages Disadvantages Indications, special features Kirschner (K-)wire fixation * minimally invasive * soft-tissue sparing * low cost * placement as intramedullary splinting or extension block pinning (modified Ishiguro technique) possible * bicortical insertion: risk of thermal bone neocrosis * 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 mtraosseous wire loop * adorsal soft-tissue span * ahigh 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. * aperiosteum 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

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).

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).

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).

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).

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).

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).

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).

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.

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.

Conflict of interest statement

ML has received lecture fees from Synthes, AO, Johnson & Johnson, Medartis, IBRA, KLS-Martin, and BIRG for courses and congresses. He received reimbursement of travel expenses and congress fees from Synthes, AO, Johnson & Johnson, Medartis, IBRA, KLS-Martin, and BIRG. He is a member of the Advisory Board AO -- Hand Expert Group of KLS Martin. He is currently President of the German Society for Hand Surgery

FU has a consultancy contract with Medartis regarding the development of a hand fixation instrument tray.

The other authors declare that there are no conflicts of interest.

Manuscript received on 19 June 2023, revised version accepted on 11 October 2023.

* Finger fractures

* Fractures of the distal phalanx: finger plaster splint with free PIP joint, on reduction of swelling, place ment 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 in-terphalangeal

e1. Giddins G: The nonoperative management of hand fractures in United Kingdom. Hand Clin 2017; 33: 473-87 CrossRef MEDLINE

e2. Reformat DD, Nores GG, Lam G, et al.: Outcome analysis of metacarpal and phalangeal fixation techniques at Bellevue Hospital. Ann Plast Surg 2018; 81: 407-10 CrossRef MEDLINE

e3. Gajendran VK, Gajendran VK, Malone KJ: Management of complications with hand fractures. Hand Clin 2015; 31: 165-77 CrossRef MEDLINE

e4. Neumeister MW, Winters JN, Maduakolum E: Phalangeal and metacarpal fractures of the hand: preventing stiffness. Plast Reconstr Surg Glob Open 2021; 9: e3871 CrossRef MEDLINE PubMed Central

e5. Balaram AK, Bednar MS: Complications after the fractures of metacarpal and phalanges. Hand Clin 2010; 26: 169-77 CrossRef MEDLINE

e6. Melf-Marzi A, Böhringer B, Wiehle M, Hausteiner-Wiehle C: Modern principles of diagnosis and treatment in complex regional pain syndrome. Dtsch Arztebl Int 2022; 119: 879-86 CrossRef MEDLINE PubMed Central

e7. de Putter CE, Selles RW, Polinder S, Panneman MJM, Hovius SER, van Beeck EF: Economic impact of hand and wrist injuries: health-care costs and productivity costs in a population-based study. J Bone Joint Surg Am 2012; 94: e56 CrossRef MEDLINE

e8. Stern PJ, Kastrup JJ: Complications and prognosis of treatment of mallet finger. J Hand Surg Am 1988; 13: 329-34 CrossRef MEDLINE

e9. Lamaris GA, Matthew MK: The diagnosis and management of mallet finger injuries. Hand (N Y) 2017; 12: 223-8 CrossRef MEDLINE PubMed Central

e10. Lögters TT, Lee HH, Gehrmann S, Windolf J, Kaufmann RA: Proximal phalanx fracture management. Hand (N Y) 2018; 13: 376-83 CrossRef MEDLINE PubMed Central

e11. Keller MM, Barnes R, Brandt C, Hepworth LM: Hand rehabilitation programmes for second to fifth metacarpal fractures: a systematic literature review. South African J Physiother 2021; 77: 1536 CrossRef

e12. Schmidt H-M, Lanz U: 7.7 Architektur der Mittelhand [Internet]. 2., überar. Chirurgische Anatomie der Hand. Stuttgart: Georg Thieme Verlag KG 2013. www.thieme-connect.de/products/ebooks/ lookinside/10.1055/b-0034-14106 (last accessed on 24 September 2023) CrossRef e13. Dial WB, Berg E: Bennett's fracture. Hand 1972; 4: 229-35 CrossRef MEDLINE

e14. Hove LM: Fractures of the hand. Distribution and relative incidence. Scand J Plast Reconstr Surg hand Surg 1993; 27: 317-9 CrossRef

e15. Liverneaux PA, Ichihara S, Hendriks S, Facca S, Bodin F: Fractures and dislocation of the base of the thumb metacarpal. J Hand Surg Eur Vol 2015; 40: 42-50 CrossRef MEDLINE

e16. Thelen S, Windolf J: Finger- und Mittelhandfrakturen. Orthopädie und Unfallchirurgie up2date 2019; 14:. https://doi.org/10.1055/a-0609-9878 (last accessed on 24 September 2023) CrossRef

e17. Zach A, Lautenbach M, Merk H, et al.: Frakturen der Phalangen. Handchirurgie Scan 2013; 02: 49-67. https://doi.org/10.1055/s-0032-1326002 (last accessed on 24 September 2023) CrossRef

e18. del Piñal F, Moraleda E, Rúas JS, et al: Minimally invasive fixation of fractures of the phalanges and metacarpals with intramedullary cannulated headless compression screws. J Hand Surg Am 2015; 40: 692-700 CrossRef MEDLINE

e19. Franssen BBGM, van Diest PJ, Schuurman AH, Kon M: Drilling K-wires, what about the osteocytes? An experimental study in rabbits. Arch Orthop Trauma Surg 2008; 128: 83-87 CrossRef MEDLINE PubMed Central

e20. Matloub HS, Jensen PL, Sanger JR, et al.: Spiral fracture fixation techniques. A biomechanical study. J Hand Surg Br 1993; 18: 515-9 CrossRef MEDLINE

e21. Diaz-Garcia R, Waljee JF: Current management of metacarpal fractures. Hand Clin 2013; 29: 507-18 CrossRef MEDLINE

e22. Carreño A, Ansari MT, Malhotra R: Management of metacarpal fractures. J Clin Orthop trauma 2020; 11: 554-61 CrossRef MEDLINE PubMed Central