
Learn the Open Reduction and Internal Fixation of the 5th Carpometacarpal Joint with Bridging Plate using Synthes 15 mm Compact Hand Set surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Open Reduction and Internal Fixation of the 5th Carpometacarpal Joint with Bridging Plate using Synthes 15 mm Compact Hand Set surgical procedure.
Punching injuries to the hand are widespread and account for significant attendances to the Emergency department. Axial loading along the metacarpus in a closed fist can result in a fracture-subluxation of the hamatometacarpal joint. These injuries are often missed on routine examination and radiographs. Poorly managed injuries can result in disabling sequelae with pain, deformity and functional loss.
These fracture subluxations can sometimes be managed by manipulation followed by stabilisation in plaster splints. More often, they require surgical intervention with minimally invasive percutaneous wiring. This technique has been described elsewhere on this website. However, occasionally, the fracture fragments are displaced to an extent where simple manipulation is insufficient to regain the normal anatomy. This is a guide for management of this challenging cohort of patients that require open reduction. The technique combines the principles of internal fixation of intra-articular fractures along with the philosophy of distraction ligamentotaxis with a bridge plate.
Readers will also find of use the following OrthOracle techniques:
Closed reduction and K wiring of 5th carpometacarpal fracture-dislocation.
Internal fixation of 5th metacarpal neck fracture (Synthes LCP plate)
Guyons canal release

Fracture dislocation of the Carpometacarpal joint (CMC Joint) has traditionally been considered an uncommon injury with a paucity of literature on its management. They account for less than 1% of the hand injuries and are more common in the dominant hand. Lilling et al (1979) discussed the mechanism and showed that an axial loading vector along the shaft of the 5th metacarpal results in disruption of the CMC joint. The displacement of the fragments is dictated by the pull of the various deforming forces of the Flexor Carpi Ulnaris, Extensor Carpi Ulnaris and Abductor Digiti Minimi.
Cain et al (1987) graded these injuries into 3 types depending upon the fracture pattern of the hamate in relation to the CMCJ subluxation:
Type 1a – Pure subluxation or dislocation with no fracture
Type 1b – Subluxation/Dislocation with associated dorsal avulsion fracture of hamate
Type 2 – Subluxation/Dislocation with comminution of dorsal hamate rim
Type 3 – Subluxation/Dislocation with coronal splitting of hamate
The classification helps in planning management of these injuries but is not necessarily prognostic of the final functional outcome.
Recently, Kim et al (2012) have proposed a variation to this classification based on CT findings.
INDICATIONS
The treatment goal is to restore normal anatomy and function to the hand. AO principles dictate an anatomical reduction and rigid internal fixation of intra-articular fractures. This facilitates early mobilisation and return to function. However the structural configuration of the complex hamatometacarpal joint makes this a challenging problem. Distraction ligamentotaxis with bridge plating is an established modality for complex comminuted intra-articular injuries. This technique combines the advantages of both these philosophies to achieve an optimal functional outcome.
My indications for this procedure are-
Type 3 fractures with a coronal split or a comminution of the hamate
Failure of manipulation in Type 1 and Type 2 injuries
Delayed or missed diagnosis
SYMPTOMS & EXAMINATION
The majority of these injuries occur secondary to high energy trauma such as direct punches against a hard object, road-traffic accidents and falls. The patient presents with pain and swelling over the dorso-ulnar border of the hand. There is tenderness over the base of the metacarpus and movements of the finger may be restricted with pain. A common finding is the presence of a bony lump over the base of the metacarpus. There may be an apparent extensor lag of the small finger at the metacarpophalangeal joint. Presence of any rotational abnormality should be evaluated and documented. Comparison can be made with the opposite uninjured hand. Open injuries must be examined for any loss of tendon and nerve function.
IMAGING
Plain radiographs are the first line of investigations for diagnosis. I always request three radiographic views of the hand – Posteroanterior, lateral and oblique. The lateral radiographic view is essential to identify the dorsal subluxation/dislocation of the base of the metacarpus. It is not uncommon to miss this in the routine PA and oblique radiographs. The metacarpal height is reduced and the metacarpal head will appear to be flexed forward. Kauffmann et al (2017) described a “hand fan sign” on oblique radiographs as a subtle indicator of the injury. Any concomitant fractures around the CMC joint are identified and their intra-articular extensions documented.
Unfortunately, these injuries are often missed on plain Xrays. Pullen et al (1995) showed that CT scans are the ideal modality to diagnose and delineate the pathoanatomy of these fractures. This is particularly true for Type 2 and 3 fractures to enable planning of adequate management. We routinely perform a CT scan for these injuries at our Unit.
ALTERNATIVE TREATMENT
“Masterful inactivity”: Immediate mobilization of the hand and fingers with pain relief has been tried by Petrie & Lamb. Despite obvious radiographic abnormalities at 4-year follow-up, there was no significant functional disability identified in their cohort. Unfortunately, these results have not been reproducible elsewhere.
Conservative with closed reduction followed by plaster immobilisation: This is best reserved for stable injuries with no significant displacements of the fracture fragments (Cain Type 1). Unfortunately, injuries associated with displaced intra-articular fractures are not amenable for reduction with manipulation.
Closed reduction and percutaneous pinning: This procedure has established itself as the “Gold Standard” for the management of carpometacarpal fracture subluxations. A step-by-step guide is available elsewhere on this website. However, the success of the technique is dependent on adequate restoration of the anatomy by closed manipulation. This is often unattainable in Type 3 injuries. The additional complications of pin-track infections and splint immobilization are a secondary source of problems.
Closed reduction and external fixator:This device will span the CMC joint and allows reduction with ligamentotaxis. Again, this technique depends on the anatomical restoration with manipulation and distraction – which is often not possible in this cohort of patients. Moreover, placement of proximal pins in the small carpal bones can be technically challenging. Finally, the device requires meticulous pinsite care in the postoperative period to prevent infections and complications.
Salvage: Untreated or redisplaced injuries often present with pain and reduced grip strength. This is related to secondary osteoarthritis at the CMC joint with/without persistent subluxation. Such cases will require salvage procedures such as resection arthroplasty, interposition arthroplasty or an arthrodesis.
CONTRAINDICATIONS: There are no specific contraindications.
Lilling M, Weinberg H. The mechanism of dorsal fracture dislocation of the fifth carpometacarpal joint. The Journal of hand surgery. 1979 Jul 1;4(4):340-2.
Cain Jr JE, Shepler TR, Wilson MR. Hamatometacarpal fracture-dislocation: classification and treatment. The Journal of hand surgery. 1987 Sep 1;12(5):762-7.
Kim JK, Shin SJ. A novel hamatometacarpal fracture–dislocation classification system based on CT scan. Injury. 2012 Jul 1;43(7):1112-7.
Kauffmann P, Le Borgne P, Slimani H, Quoirin E, Bejinariu L, Bilbault P. Signe de l’éventail dans la luxation carpométacarpienne dorsale. Journal de Traumatologie du Sport. 2017 Mar 1;34(1):62-4.
Pullen C, Richardson M, McCullough K, Jarvis R. Injuries to the ulnar carpometacarpal region: are they being underdiagnosed?. Australian and New Zealand journal of surgery. 1995 Apr;65(4):257-61

Informed consent is an important part of the procedure and the risks and benefits should be clearly explained to the patient. The dorsal branch of ulnar nerve lies in close proximity and can be injured either by the fracture fragments or during surgical exposure. The ulnar nerve in the Guyon’s canal is at risk of injury during the fixation process with screws. The metalwork straddles the joint and should be removed, necessitating a second surgical procedure. Lastly, the intra-articular fragmentation can be a precursor for future secondary osteoarthritis of the CMC joint.
I prefer regional anaesthesia with axillary block for this procedure. The patient is placed supine with the limb extended on an arm table and supported on a lead hand. Upper arm tourniquet is applied and inflated after exsanguination. A prescrub is performed followed by a sterile prep with Chlorhexidine. I routinely administer a single dose of antibiotics for this procedure.

Finger mobilization exercises are commenced immediately. The wound is redressed within a week when formal therapy exercises with full active mobilsation of the hand are started. Sutures are removed at 2 weeks. Activities of daily living can be commenced as soon as pain allows. Mobilisation exercises of the hand and wrist are progressively increased. Xrays are repeated at 6 weeks to confirm fracture healing. I advise patients against heavy activities until the fracture is consolidated.
Stiffness is a common complication following this injury and its surgical fixation. Extensor tendon adhesions are partly to blame and can be minimized with early therapy and scar massage. I have not yet had to reexplore for extensor tenolysis in my practice.
The movements in the 5th CMC joint play a critical role in the cupping and gripping manoeuvres of the hand. The bridge plate spans the CMC joint and should be removed in a second procedure. I wait for atleast 6-8 weeks before planning the removal of metalwork. The follow-up surgery can be undertaken through the previous scar taking similar precautions to protect the dorsal cutaneous branch of the ulnar nerve during the surgical approach.

Yoshida R, Shah MA, Patterson RM, Buford Jr WL, Knighten J, Viegas SF. Anatomy and pathomechanics of ring and small finger carpometacarpal joint injuries. The Journal of Hand Surgery. 2003 Nov 1;28(6):1035-43. This was a cadaveric study that recreated the axial loading force using a customised jig to identify the injury patterns. The 20 specimens were examined fluoroscopically as well as with detailed dissection to analyse the correlation between the injury patterns and the ligament anatomy. The authors recognise the complex patterns of injury and detail them. This is a good article to understand the rationale of investigations and treatment of this injury
Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. European Journal of Trauma and Emergency Surgery. 2016 Feb 1;42(1):37-42. This paper reviews the literature for the etiopathogenesis, investigation modalities and treatment options for these injuries. They summarise that operative fixation is the ideal treatment to restore anatomy and function in the hamatocarpal fracture dislocations.
Jung HS, Song MK, Lee JS. Use of the bridge plate technique for the treatment of hamatometacarpal fracture-dislocations. The Journal of Hand Surgery (Asian-Pacific Volume). 2020 Mar;25(01):67-75. The authors present their outcome of treatment using a bridge plate across the CMC joint in 16 patients. They reported excellent functional recovery with all patients returning to their original jobs within 5 weeks. They concluded that this was an effective treatment modality for these complex injuries.
Chaves C, Dubert T. Ulnar-sided carpometacarpal fractures and fractures-dislocations. A systematic review and publication guidelines. Orthopaedics & Traumatology: Surgery & Research. 2020 Oct 21. This paper reviewed 500 articles on this injury published over a 100 years. They recognized that the low incidence of the injury resulted in a plethora of case series. However, they were able to conclude that conservative treatment and percutaneous pinning should be reserved for the stable injuries. They suggested that unstable injuries and those with delayed presentation are best treated with open fixation.