Isolated volar dislocation of the distal radioulnar joint: a case series and systematic review

Abstract

Introduction

Isolated volar dislocations of the distal radioulnar joint are reported as rare. We observed three such cases over a 12-month period. Literature to date consists of multiple case reports and case series with no structured reviews. There is debate as to incidence, mechanism, investigation, treatment and prognosis.

Methods

A case series and formal systematic review was performed. This included an analysis of the demographics, mechanism, presentation, investigation, treatment and outcome of the cases identified from the wider published series.

Findings

In total 99 cases of this injury were identified from 59 papers, with a further 9 cases having an associated ulna styloid fracture.

Conclusions

This is a rare injury, representing up to 0.02% of all bony injuries, which is diagnosed late in 36% of cases. Inability to obtain a true lateral radiograph may contribute to the diagnosis being missed. Computed tomography scans are useful in suspected cases without radiographic confirmation. Acute cases are successfully treated with closed reduction in 78% of cases; however associated soft tissue injuries may need to be surgically addressed. Delayed presentation is more likely to require open surgery and preoperative MRI scans are indicated to aid surgical planning. Chronic instability rarely occurs and may need treatment with reconstruction or salvage. A good, subjective, result is reported in the majority of patients.

Introduction

Most disruptions of the distal radioulnar joint (DRUJ) are associated with radial fractures, the so called Galleazi fracture.¹ The majority of DRUJ dislocations without a fracture occur when the distal ulna dislocates in a dorsal direction.¹

Isolated volar dislocations of the DRUJ are reported as rare. We observed three such cases over a 12-month period, which prompted us to perform a literature search with a view to publishing a case series. Initial review of the literature identified several case reports and small case series, published in the last 3 years, that all agreed that the injury is rare, citing between 3 and 9 other publications and describing up to a total of 36 cases in the literature. There seemed to be a lack of agreement as to the mechanism of injury, clinical signs and the best imaging modality to use. Several reported late presentations and missed diagnoses. There seemed to be a debate about the best method of reduction and the need, or otherwise, for treatment of associated soft tissue injuries.

Our initial review suggested that there were several more published cases in the literature than had been previously reviewed. It therefore suggested that a systematic review of all the cases of isolated volar dislocations of the DRUJ in the literature, including our own case series, would be a useful addition and may generate evidence-based answers to some of these questions.

Methods

We (OOM and LD) reviewed the case notes, physiotherapy notes and radiology of the three patients identified in our series. This was done prospectively for cases 2 and 3 and retrospectively for case 1, who had finished treatment and been discharged. Only subjective outcome measures were used owing to the small number of cases in the series.

In order to identify all case reports and case series of isolated volar dislocations of the distal ulna, a database search was undertaken on 29 October 2021 using Medline, EMBASE, CINAHL, EMCARE and PubMed databases using the search terms volar or anterior* or palmar’; and subluxation* or luxat* or dislocat* or dis-locat*; and distal ulna* or ulna head* or distal radioulnar* or distal radioulnar* or DRUJ.

The results of this search were screened for eligibility by OCB and DJB and all appropriate full texts were obtained. ‘Backwards and forwards citation searching’ was then performed against the reference lists of the appropriate articles and the citation lists from both Google Scholar and PubMed. This search ceased on 30 November 2021.

Foreign language sources were translated using Google Translate and included as appropriate. Case reports where only the abstract was available were included if the abstract contained sufficient information to confirm the case report was relevant. Case reports in children under the age of 16 years were excluded.

All relevant case reports and case series were then reviewed by OCB and DJB to obtain information including age, sex, hand affected, mechanism of injury, associated injuries, time from injury to treatment, treatment and outcome. In terms of delay to diagnose and treat we defined ‘acute’ as within 1 week, ‘delayed’ as between 1 and 6 weeks, and ‘late’ as after 6 weeks.

Owing to the nature of case reports and case series, not all these data were included in all papers. In the results and discussion sections we quote figures and percentages out of the number of cases where that fact was known, and this is stated as an ‘n’ number in parentheses. Where appropriate, to assess statistical significance, the two-tailed Fisher’s exact test was used with the level of significance set at p<0.05.

Results

Case series

Case 1 was a 45-year-old man who had sustained a right isolated volar DRUJ dislocation (Figure 1) when a metal cage fell on to his outstretched supinated hand. He presented with wrist pain and ulna volar swelling, and his wrist was fixed in a mid-pronated position with no active or passive rotation. Closed reduction under sedation, using in line traction and counter traction, applying pressure to the ulnar head was successful (Figure 2). The arm was placed in an above-elbow backslab. A post-reduction magnetic resonance image (MRI) scan showed normal alignment of the DRUJ with no associated fractures. The triangular fibrocartilage complex (TFCC) appeared grossly intact but both the volar distal radioulnar ligament and the extensor carpi ulnaris (ECU) subsheath were torn with the tendon itself intact. He was immobilised for 6 weeks. At 3 months he was pain free, had progressed to a full range of movement (ROM) at his wrist and had no DRUJ laxity.

Figure 1 .

Case 1: posteroanterior and lateral radiograph on admission

Figure 2 .

Case 1: posteroanterior and lateral radiograph post reduction

Case 2 was a 26-year-old man who sustained an isolated right volar dislocation of the DRUJ sustained while punching a wall at an oblique angle. He presented with significant wrist pain. On examination, active and passive movements were restricted, allowing only 45° of flexion. Following an unsuccessful attempt at closed reduction under sedation, the patient was placed into an above-elbow volar slab and a computed tomography (CT) scan was requested. Six days later he underwent a closed manipulation under anaesthesia, delayed owing to the COVID-19 pandemic. The wrist was hypersupinated and then direct pressure was placed on the ulnar head resulting in a successful reduction. An above elbow cast was applied in pronation for 2 weeks followed by 3 weeks in a sugar-tong cast. On completion of his physiotherapy programme at 6 months he had regained a full, and pain-free, ROM and normal function of his wrist.

Case 3 was an 18-year-old man who injured his right wrist in a rugby tackle. He presented with a painful loss of forearm rotation. Radiographs the following day were assessed as normal, but review of these at 7 days post injury revealed the diagnosis. An MRI scan confirmed the diagnosis; it suggested the TFCC was intact but confirmed a tear to the ECU subsheath. Closed reduction under anaesthesia, 3 weeks post injury, was successful, and after reduction, the joint was stable. Immobilisation in an above-elbow cast for 4 weeks was followed by physiotherapy. At 3 months he was pain free with a stable DRUJ. He had full ROM at the wrist and DRUJ.

We observed three cases of isolated volar DRUJ dislocation in our unit over a 1-year period. It should be noted that, although case 3 was identified in a neighbouring hospital, during the preparation of the manuscript we have identified a further (3^rd) case in our unit. During the same time, the unit was referred over 18,000 fractures and dislocations and approximately 1,500 distal radius fractures. Isolated volar DRUJ dislocation thus represents approximately 0.02% of all bony injuries treated in our unit in that period and is 500 times rarer than a distal radius fracture.

Literature review

The original database search identified 219 potential studies. We discounted 157 as not relevant, mainly due to associated radial fractures; being dorsal dislocations; being in animals or children; or duplications. We attempted to obtain the full text of the remaining 62 papers. ‘Backwards and forwards citation searching’ identified another 37 papers, and again we attempted to obtain the full text.

Of the 99 full-text papers, we were unable to obtain 19; however, in 12 there was sufficient information in the abstract to confirm that the cases could be included in our numbers. In six, it was obvious that the case was not relevant and these were excluded, and in a further three it was not possible to identify any relevant information, so these were again excluded.

Of the 80 full-text papers obtained, a further 22 were excluded as they were found not to be relevant. Of the remaining 58, 8 were case series containing 2 (n=4), 3 (n=3) and 5 (n=1) relevant patients. In one of the earliest papers identified, Cotton and Brickley, in 1912, published a detailed description of a further 27 cases.² There were no studies of higher evidence level than a short retrospective case series.

As a result, a total of 108 isolated volar distal ulnar dislocations have been identified, 9 of which have an associated ulna styloid fracture, and were included as this probably represents the same injury. There were three further injuries where the dislocation was associated with an ulna neck or head fracture that were excluded, as this probably represents a different injury.

The details of all the cases included in the final analysis are presented in Table 1 and include an abridged citation to confirm which cases were included (as not all are included in the references of this paper).

Table 1 .

List of all cases of isolated volar DRUJ dislocations identified from the literature

First author	Year	Citation	First author	Year	Citation
Petrevski	2021	AJTES; 5(2): 887–890	Riddoux	1996	Rev Chir Orthop; 82(3): 255–259
Morisaki	2021	J Hand Surg (AP); 26(3): 472–476	Poyatos	1996	Rev Ortop Traumatol; 40(1): 44–46
Glazier	2021	Cureus; 13(6): e15656	Gale	1994	J R Coll Surg Edinb; 39(3): 196–197
Fanjalalaina	2020	Ann Afr Surg; 17(2): 93–96	Newman	1994	Injury; 25(4): 259–261
Jin	2020	BMC Surg; 20(1): 71	Kashyap	1994	Orthopedics; 17(7): 634
Jalal	2019	J Traumatol du Sport; 36(3): 203–206	Singletary	1994	Ann Emerg Med; 23(4): 881–883
Lin	2019	BMC Musculoskelet Disord; 20(1): 368	Schiller	1991	J Bone Joint Surg Am; 73(4): 617–619
Larrivee	2018	Case Rep Orthop; 2018: 4289406	Francobandiera	1990	Med Sci Sports Exerc; 22(2): 155–158
Duryea (2)	2016	Skel Radio; 45(9): 1243–1247	Obiltschnig	1990	Unfallchirurgie; 16: 225–229
Kohyama	2015	Trauma; 17(3): 229–234	Sanders	1989	Orthopedics; 12(11): 1473–1476
Zannou	2015	Case Rep Plast Surg Hand Surg; 2(2): 43–45	Paley	1986	Orthop Rev; 15(4): 228–231
Tang	2014	J Hand Surg (AP); 19(3): 413–417	Rainey	1985	Orthopedics; 8(7): 896–900
Pfaff	2014	Ned Tijdschr Geneeskd; 158: A7433	Morrissy (2)	1979	Clin Orthop Related Res; 198: 141–151
Werthel	2014	Chir Main; 33(5): 364–369	Paszkiewicz	1974	Chir Narzadow Ruchu Ortop Pol; 39(2): 129–132
Vles	2013	Ned Tijdschr Geneeskd; 157(20): A5777	Weseley	1972	J Trauma; 12(12): 1083–1088
Slattery	2013	Eur J Orthop Surg Traumatol; 23 Suppl 2: S203–S205	Dameron (4+1)	1972	Clin Orthop Related Res; 83: 55–63
Tarallo	2013	J Hand Surg Eur; 38(5): 572–574	Head	1971	Brit J Radiol; 44(522): 468
Ellanti	2012	J Hand Surg Eur; 37(1): 72–75	Heiple (2)	1962	J Bone Joint Surg Am; 44: 1387–1394
Mulford	2010	J Trauma; 68(1): E23	Rose-Innes (1+1)	1960	J Bone Joint Surg Br; 42: 515–523
McMurray	2008	Injury Extra; 39: 352–355	Seidenstein	1956	J Bone Joint Surg Am; 38(5): 1137–1141
Garrigues	2007	J Bone Joint Surg; 89(7): 1594–1597	Curr (3)	1946	Brit J Surg; 34: 74–75
Quah	2006	Internet J Orthop Surg; 7(2): 1–4	Cox	1942	Surgery; 12: 41–45
Boulares	2004	Chir Main; 23(6): 313–315	Darrach	1912	Ann Surg; 56(5): 802–803
Mittal	2004	Eur J Trauma Emerg Surg; 11(2): 113–116	Cotton (28)	1912	Ann Surg; 55(3): 368–372
Saito (3)	2003	J UOEH; 25(2): 249–257	Desault	1791	J Chir; 1: 78
Albisson	2003	J Traumatol Sport; 20: 110–113
Sakato	2002	Chir Main; 21(5): 301–304	With ulna styloid fracture
Wallwork	2001	J Hand Surg; 26(3): 454–459	Starnoni	2019	Plast Reconstr Surg Glob Open; 7(10): e2480
Deshmukh	2001	Orthopedics; 24(2): 169–170	Bouri	2016	Int J Surg Case Rep; 22: 12–14
Takami	2000	Arch Orthop Trauma Surg; 120(10): 598–600	Li	2014	JBJS Case Connect; 4: e119
Caranfil	2000	Acta Orthop Belg; 66(5): 517–521	Sonohata	2012	Hand Surg; 17(3): 383–386
Kameyama	2000	J Hand Surg (AP); 5(2): 165–168	Rijal	2012	Eur J Orthop Traumatol; 3(2): 151–154
Kumar	1999	J Emerg Med; 17(5): 873–875	Kikuchi	2005	Hand Surg; 10 (2–3): 319–322
Putzeys	1999	Acta Orthop Belg; 65(3): 376–377	Weseley	1972	J Trauma; 12(12): 1083–1088
Stavrev	1998	Ortop Travmatol; 34(3): 132–134

Figures in parentheses after author indicate number of appropriate cases in a series. +1 refers to a series that also contains a case with an associated ulna styloid fracture.

The cases had an age range, at injury, of 16 to 79 years (n=73) but were more common in younger patients with a median age of 32. The injury is almost twice as common in males (45/71=63%) but does not seem to have a side dominance with 27 (out of 56=48%) being left-sided injuries. Considering the mechanism of injury (n=68), 21 (31%) were caused by a fall, often either with a degree of twisting (stated as supination in 5/21) or increased energy (8/21); 20 (30%) were caused by a twisting injury; 16 (24%) were caused by a direct blow (4/16 state while supinated); 2 (3%) were caused by a punching injury; and in the remaining 9 (13%) the mechanism was unclear. Where stated (n=41), 21 (51%) occurred during sport (ranging from rugby, the most common (5), to yoga, gymnastics, bullfighting and parachuting), 14 (34%) occurred at work and 6 (15%) during some sort of altercation.

Twenty-eight cases (26%) reported associated injures, including six disruptions to the TFCC, which is likely to represent the same mechanism of injury seen with the nine cases with associated ulna styloid fractures. Other soft tissue injuries include three with disruption of the volar distal radioulnar ligament; two with tears of pronator quadratus; and one with injury to the interosseous membrane. In seven there was an associated osteochondral defect of the ulna head caused by impaction against the volar rim of the sigmoid notch. There was one simultaneous radial head dislocation.

In terms of delayed diagnosis, our review of the literature found that 44 (64%) cases (n=69) were identified within 1 week, 8 (12%) within 6 weeks and 17 (25%) were identified later. Further we found that cases in the first half of the series (published pre-2005) have a significantly higher rate of being missed for longer than a week (16/35) compared with those published since then (9/33, p=0.043).

Of the papers where treatment was discussed (n=87), 46 patients were treated with a closed reduction, 41 required an open reduction/procedure, 9 required the DRUJ to be stabilised with a K-wire after reduction, 6 had a procedure to their TFCC and 4 a capsular repair. Twelve patients required some sort of salvage procedure, seven patients underwent a Darrach’s procedure, four a Sauvé–Kapandji and one a matched hemiresection arthroplasty. Eleven out of these 12 salvage procedures were in cases with late presentation, and all were in the early half (pre-2005) of the series. Closed reduction was the definitive treatment in 34 of the 44 injuries diagnosed acutely (77%), whereas 15 out of 17 (88%) injuries diagnosed late required open surgery (p<0.001). There were three cases of late instability after initial closed treatment.

Of the 61 who reported the outcome of the injury, 47 reported good results, 13 fair or reasonable and only 1 poor (despite 15 cases requiring some sort of late reconstruction or salvage procedure). Of the 34 acute cases, successfully treated with closed reduction, 28 reported their outcome: this was reported as good in 27 (96%) and reasonable in 1. It should be noted that all of these outcomes were subjective, and none reported objective outcome measures.

There was no obvious difference in any of the observed parameters in injuries associated with an ulna styloid fracture or not.

Discussion

Isolated volar DRUJ dislocation is a rare injury representing 0.02% of all bony injuries in our hospital. The true incidence is almost certainly less than this as it was only the clustering of cases that brought the condition to our attention. Indeed, none of the authors is aware that they have seen this injury previously.

The only evidence in the literature is from case reports and small retrospective case series. There are no comparative studies, there is universally incomplete data, and most series and results are subjective. It is not possible, therefore, to form absolute conclusions; however, we are able to make some observations and recommendations.

There seems to be agreement that the injury was first identified by Desault in 1777 and published in 1791.³ He described ‘a cadaver case, without history’, but one that was undoubtedly a case of ‘forward luxation of the ulna alone, without fracture’.² Many papers erroneously suggest the first case was instead reported by Darrach in 1912⁴; interestingly, although this paper does describe a case, it is also the first paper to describe the procedure of excision of the distal ulna, which bears his name.⁴ In the same year Cotton and Brickley reviewed the literature and identified no fewer than 27 published cases.²

Desault’s case³ was, by necessity, diagnosed in a cadaver as it pre-dated the invention of the x-ray in 1895 and its wider introduction into clinical practice in the early 1900s. Cotton and Brickley were the first to identify this, explaining that the first 21 of the 27 cases they presented pre-dated the x-ray.² The early surgeons, including Desault, recognised that the injury was not anatomically an ulna dislocation and instead it was ‘the radiocarpal unit that dislocated from the anatomically located ulna’, but accepted the convention of describing the dislocation according to the position of the ulna relative to the radius.⁵ They also described the ‘classical’ clinical findings of a ‘hollow’, ‘sulcus’ or ‘gutter’ on the back of the wrist where the ulna head should be and a ‘narrowed wrist’, due to the ulna lying volar and overlapping the radius (due to the pull of pronator quadratus).⁶ All agreed there would be a painful loss of forearm rotation, usually from a supinated position.^2,5,7

Cotton and Brickley also identified two mechanisms of injury: a ‘forced supination’ or a ‘direct backward shove’³ whereas Darrach’s case was caused by ‘severe pronation’.² More recently these descriptions have been refined⁸ to a forced supination of the forearm on a fixed hand; a forced pronation to the hand with the forearm fixed; and a direct dorsally applied force to the distal ulna. Review of the mechanisms identified in this review would suggest that a direct volarly applied force to the distal radius or carpus would also cause the same lesion.

The injury is reported as ‘frequently missed’; with a figure of 50% often quoted which traces back to Weseley et al’s review of the literature.⁷ Our review suggests a lower figure of 36%. Failure to perform a true lateral radiograph may contribute to the injury being missed.^9,10 In a true lateral radiograph, the proximal scaphoid should overly the lunate and the pisiform should overlap the distal pole of the scaphoid.^9,11 The alternative, referencing the lateral by attempting to get the distal radius and ulna to overlap, is likely to miss the injury.¹¹ Further, as the injury causes a loss of forearm rotation, it may not be possible to get a true lateral radiograph. We recommend that anyone with a significant lack of forearm rotation, with no obvious bony injury should have a CT.^9,11

Treatment of an acute dislocation is by closed reduction under either sedation or anaesthesia. In acute injuries this is successful in 77% of cases. There are several descriptions of techniques for closed reduction, which are essentially unchanged since the early case series. They involve a combination of traction, an attempt to widen the gap between radius and ulna with fingertips pulling the radius radially (the Boyer manoeuvre); pushing the ulna head dorsally; and pronating the wrist.³

Many authors state that a successful closed reduction after three weeks is not possible, based upon publications by Paley et al⁵ and Dameron.⁶ We have identified two cases where this has been successful; however, in one, at 7 months, the reduction needed to be augmented with a K-wire¹²; and in the other, at 10 months, the dislocation recurred and a Sauvé–Kapandji procedure was required.¹³

The presence of the variety of associated soft tissue lesions described in the literature is likely to explain both the inability to achieve a closed reduction in the minority of the acute dislocations and the inability to maintain that reduction. It seems unlikely that the distal ulna could dislocate volarly (or the radiocarpal unit dorsally) without tearing the volar distal radioulnar ligament, and possibly the pronator quadratus muscle. Further displacement is likely to injure the superficial or deep insertion of the TFCC or avulse the ulna styloid, as well as the ECU subsheath. Even higher-energy injuries may damage the interosseous membrane and may even lead to a simultaneous dislocation of the radial head.¹⁴ Forcible dislocations or relocations may cause an associated osteochondral defect of the ulna head caused by impaction against the volar rim of the sigmoid notch, with several authors comparing this to a Hill–Sachs lesion.^15,16

Despite this, 98% of patients treated with simple closed reduction have, at least subjectively, a good outcome. We therefore recommend that closed reduction should be the initial treatment. After reduction, the DRUJ should be tested for stability. If stable, simple immobilisation in an above elbow (or sugar-tong) cast for 4–6 weeks is all that is required. The literature would suggest that unstable joints should be immobilised with transosseous wires for 4–6 weeks. Further, in the case of unstable joints, a subsequent MRI scan has been shown to be useful to identify associated soft tissue injuries and to assess if these are likely to require reconstruction. There is no obvious evidence to support the routine use of MRI prior to reduction of acute, or delayed, injuries.

Open reduction is indicated for late presentation or diagnosis, and volar, dorsal and true ulnar approaches have been described. Here, owing to the high failure rate of closed reduction and the higher need for surgical repair of associated injuries, a pre-op MRI is advised to identify the pathology and guide the approach. Stabilisation procedures, including those described by Sanders and Hawkins¹⁷ and Adams and Berger,¹⁸ have been utilised for instability following the injury, although more frequently in cases of chronic instability. Salvage procedures such as those described by Darrach and Sauvé–Kapandji may also be indicated. The decision as to whether to do a soft tissue reconstruction or a bony procedure is based mainly on the presence or absence of significant damage to the articular surface of the ulna head, as well as the functional demands of the patient.

Finally, it should be noted that some of these descriptions of treatment with ulna head excision are historic and have been performed in younger patients than would now be advocated. A detailed description as to how to manage articular damage with instability in a younger patient has not been published with reference to isolated volar DRUJ dislocation and is beyond the scope of this current paper.

Conclusion

In conclusion, isolated volar DRUJ dislocation is a rare injury accounting for up to 0.02% of all bony injuries. There are, to our knowledge, 99 cases of isolated volar DRUJ dislocation in the literature and a further 9 with an associated ulna styloid fracture.

There are four mechanisms that cause the injury which presents with pain, a narrowed wrist, with a sulcus on the dorso-ulnar aspect and decreased forearm rotation. The diagnosis is usually made with posteroanterior and true lateral radiographs; however, CT is indicated if these are not conclusive.

Closed reduction is sufficient treatment in most acute cases, and post-reduction instability should be treated with K-wire fixation. MRI is indicated in the case of post-reduction instability to identify associated injuries that may need to be addressed surgically. In the cases of late diagnosis, preoperative MRI is indicated to identify associated soft tissue lesions and plan the surgical approach.

A good outcome is expected in most cases, but late reconstructive or salvage surgery is occasionally required, especially with a late diagnosis.