Surgical fixation of distal ulna neck and head fractures

Objectives Distal ulna plate fixation for ulnar neck and head fractures (excluding ulnar styloid fractures) aims to anatomically reduce the distal ulna fracture (DUF) by open reduction and internal fixation, while obtaining a stable construct allowing functional rehabilitation without need for cast immobilization. Indications Severe displacement, angulation or translation, as well as unstable or intra-articular fractures. Furthermore, multiple trauma or young patients in need of quick functional rehabilitation. Contraindications Inability to surgically address concomitant ipsilateral extremity fractures, thus, limiting early active rehabilitation. Stable, nondisplaced fractures. Need for bridging plate or external fixator of distal radiocarpal joint. Surgical technique An ulnar approach, with a straight incision between the extensor and flexor carpi ulnaris. Preservation of the dorsal branch of the ulnar nerve. Reduction and plate fixation with avoidance of plate impingement in the articular zone. Postoperative management Postoperatively, an elastic bandage is applied for the first 24–48 h. In isolated DUF with stable fixation, a postoperative splint is often unnecessary and should be avoided. For the first four weeks, only light weightbearing of everyday activities is allowed to protect the osteosynthesis. Thereafter, heavier weightbearing and activities are allowed and can be increased as tolerated. Results The best available evidence likely shows that for younger patients with a DUF, with or without concomitant distal radius fractures, open reduction and internal fixation can be safely achieved with good functional outcome and acceptable union and complication rates as long as proper technique is ensured.


Introductory remarks
Distal ulna fractures (DUF) are a frequent concomitantinjuryindistal radius fractures (DRF) and to a lesser extent observed as isolated injury.The mechanism of injury is most often a fall on an outstretched hand.The distal ulna comprises the ulnar styloid, ulnar head, and distal ulnar metaphysis (neck).However, a distinction is often made between ulnar styloid pro-cess (USP) fractures and ulnar head and neck fractures.Logan et al. describes ulnar head fractures as either solitary or combined with an extra-articular component of the distal ulna (e.g., ulnar styloid).Ulnar neck fractures are considered so if they are within 5 cm of the distal dome of the ulnar head [16].Ulnar styloid process fractures seldomly occur as a solitary fracture, but are most regularly observed as concomitant injury in distal radius fractures (± 60% of cases) [19].Most USP fractures can be managed nonsurgically without compromising functional outcome [20].However, in case of distal radioulnar joint (DRUJ) instability, triangular fibrocartilage complex pathology, or USP non-union, surgical fixation may be required [3].Szalay et al. demonstrated that fixation of the USP with an angle stable hook plate is a viable and successful option when surgery is indicated [12].Therefore, this article will focus on surgical treatment of distal ulna fractures excluding fractures of the ulnar styloid process.
For the treatment of distal ulnar fractures, excluding USP, evidence is sparse and limited to case series, retrospective studies, and only a few prospectively designed studies [6,7,10,18,19].Distal ulna fractures are observed as a concomitant injury in distal radius fractures in approximately 5% of cases [3].Isolated ulnar head and neck fractures comprise less than 20% of all (non USP) DUF fractures [19].The "Arbeitsgemeinschaft für Osteosynthesefragen" (AO) has established a comprehensive, simple, and frequently used classification, although it does not predict outcome or dictate treatment decisions (.Fig. 1; [1]).
For DUF, necessity of fixation can be debated and is not commonly performed.For example, in elderly patients with DUF and concomitant DRF, conservative management of the DUF with cast immobilization has proven successful after rigid fixation of the DRF [5, 15,21].However, fixation of DUF restores anatomical alignment and congruency of the DRUJ and allows for early mobilization.This is important as over time articular incongruity of the joints in the wrist (DRUJ, radiocarpal and midcarpal) leads to osteoarthritis in over 90% of patients [13].Furthermore, fixation restores tension on the distal oblique bundle which in turn also adds to DRUJ alignment [2].This also could be advantageous to prevent DRUJ instability and subsequently osteoarthritis [2,27].Fixation of DUF also prevents secondary problems related to ulnar and DRUJ instability after mal-or non-union of the distal ulna.
In concomitant DRF, fixation of the radius may restore DRUJ congruency and stability by tension on the distal oblique bundle.However, this is dependent on fracture morphology related to the distal oblique bundle anatomy [15].Therefore, several previous reports have suggested to assess DRUJ stability after DRF fixation and perform DUF fixation in cases of instability [5,10,15].Furthermore, DUF fixation could be advantageous to aid in stability of the radius open reduction and internal fixation (ORIF) and allows early active motion.Other indications for DUF fixation mentioned in literature are fracture angulation of ≥ 10°, ≥ 3 mm of ulnar shortening, or translation ≥ 1/3 of the diaphysis, instability of the distal ulna head/ neck or fracture fragment motion with passive forearm motion and lastly articu-lar displacement [6, 23,26,28].However, it should be noted that these suggested indications are based on expert opinion rather than scientific evidence.
The purpose of this paper is the description of the surgical technique for this delicate procedure.Fig. 3 8 For optimal surgical access, the ulnar approach is applied.Before incision the ulnar styloid is palpated (distal transversal line), the ulnar ridge of the ulna is palpated 5 cm proximal (proximal transversal line).A straight, longitudinal incision between the extensor and flexor carpi ulnaris is made (dashed line), approximately 5 cm in length, starting at the level of the ulnar styloid process (USP).In order to protect the dorsal branch of the ulnar nerve (DBUN), care is taken to limit the incisional depth to the dermis, especially in the distal part of the incision

Surgical Techniques
Before wound closure, DRUJ stability is assessed using the manual shuck examination maneuver [11].Comparison with the uninjured side can be helpful to adequately assess instability.Any residual DRUJ instability can now be addressed depending on the injury pattern.Many specific techniques to achieve this are available; however, USP fracture fixation when present or fixation of the distal ulna to the distal radius in stable rotational position with a Kwire are most frequently used.In this case, DRUJ was stable.The wound is sutured intracutaneously.

Postoperative management
Postoperatively, an elastic bandage is applied for the first 24-48 h.In isolated DUF with stable fixation, a postoperative splint is often not necessary and should be avoided.The goal is to ascertain active range of motion early after surgery, thus, fixation should strive to provide enough stability to allow this.Alternatively, the wrist is placed in a short lower arm splint for pain control and soft tissue healing for 2-4 weeks.This could be indicated in cases with concomitant distal radius fracture ORIF, osteoporotic bone and/or uncertainty of fracture stabilization.
A special indication for postoperative casting could be persistent DRUJ instability after DUF fixation.In this situation the primary choice of treatment is upper arm casting in a stable position for 4-6 weeks, to maximize limitation of pro-and supination.
For the first 4 weeks, only light weightbearing (weight < 2 kg) of everyday activities is allowed to protect the osteosynthesis.Thereafter, heavier weightbearing and activities are allowed and can be gradually increased as tolerated.
Postoperative outpatient clinic evaluation is performed with standard anteroposterior (AP) and lateral radiographs.As a general guideline this could be done at: 2 weeks to assess early surgical failure and any revision at this stage is possible; 6 weeks to assess early signs of consolidation and osteosynthesis integrity (i.e., early signs of bone healing issues like delayed union/non-union could be visible at this point as osteolysis around screws or hardware loosening); 3 months to assess full consolidation of the fracture.At this stage, range of motion can also be assessed and especially forearm rotation should be determined.
Plate removal is indicated in patients with complaints at 6 months or later.

Case report
An 81-year-old woman was admitted to the emergency room (ER) after a fall on her outstretched right hand.During physical examination swelling, functional limitation, dislocation and pain were observed.X-ray imaging showed a volar angulated distal radius and subcapital ulna fracture (.Fig. 11a).After unsuccessful reposition and secondary dislocation the patient was advised to undergo surgery for both distal radius and distal ulna fractures via open reduction internal fixation.Intraoperative fluoroscopy images showed anatomic reduction of the distal radius and ulna fractures (.Fig. 11b).Follow-up X-rays showed adequate fracture healing with maintained radial height, angulation and DRUJ congruency (.Fig. 11c).

Outcome literature
Several studies have analyzed outcome of operative techniques on the distal ulna.Dennison retrospectively reviewed 5 patients with unstable DUF in concomitant DRF, who underwent ORIF [6].All patients went on to union, had good to excellent alignment and motion, and nearly symmetric grip strength.
Ozkan et al. retrospectively identified 277 patients with an ulnar neck fracture associated with a DRF [22].The purpose of their study was to identify factors asso-Hier steht eine Anzeige.Ruchelsman et al. performed Darrach resection of the distal ulna in fractures deemed unreconstructable [24].They hypothesized that when anatomic restoration and stable fixation was not possible that resection would yield satisfactory results.Eleven patients with concomitant DUF underwent a Darrach procedure.At a mean of 42 months follow-up, the modified Gartland and Werley scores were 7 excellent and 4 good.No patients had distal ulna instability and none required secondary surgery.
Five studies compared outcome of fixation of DUF as a concomitant injury of a DRF versus non-operative treatment for the ulna [5,7,14,17,18].Four studies were retrospective in design and only one For both the isolated and concomitant DRF group, the PRWE was worse in the operated group.This study also examined the association of osteoarthritis, found radio-graphic signs in 22 DRUJ (33%) and this was associated with worse PRWE scores.
Range of motion was examined in four studies.Kurozumi et al. found a 30°decreased arc of dorsipalmar flexion in operated DUF patients compared with nonoperative group (129 vs 158, p = 0.01) [14].The other studies found no difference in range of motion.
With regard to bony union, no statistically differences were found in any of the studies.However, sample size and low prevalence of non-union may have led to a type II error.Therefore, no reliable conclusion can be drawn for these data.When all studies are combined, a non-union rate of 3.3% for operated DUFand 0.5% for nonoperative patients is calculated.
Outcomes reported in the literature should be considered with care.In current practice, decision of best approach, positioning of the plate (dorsal, dorsoulnar, ulnar or palmar), and indications for surgery often differ and still pose a challenge in the treatment of distal ulnar fractures.

Fig. 4 8 aFig. 5 8 aFig. 6 8 acFig. 7 9 aFig. 8 8Fig. 9 8 aFig. 10 8
Fig. 4 8 a Skin retractors are used to display the surgical site.The dorsal branch of the ulnar nerve must be identified.The dorsal branch of the ulnar nerved (DBUN) emerges at the dorsal border of the flexor carpi ulnaris on average 5 cm proximal to the pisiform.It then runs subcutaneously and crosses volar over the extensor carpi ulnaris (ECU) [4, 9].Further division of the subcutaneous tissue is therefore performed with spreading scissors until the fascia is encountered.b Blue dashed circle indicates the area where the DBUNcan often be encountered.Yellow line Schematic trajectory of DBUN.Black lines Indicate the volar (lower line) and dorsal (upper line) borders of the ECU tendon

Fig. 11 8
Fig. 11 8 Pre-, intra-, and post-operative images of patient with distal ulnar fracture and concomitant distal radius fracture.a Pre-operative X-ray images in the anteroposterior (AP) and lateral direction.b Intraoperative fluoroscopy image of fully fixated distal radius and distal ulna fractures.c Post-operative X-ray images in AP and lateral direction with osteosynthesis in situ had a prospective design [5].The average age in all studies was above 50 years old, with the highest average age of 82 years old in the study by Lutsky et al.Kurozumi et al. and Cha et al. analyzed functional outcome with the DASH scores and found no difference between surgically and nonoperatively treated patients [5, 14].The patient-rated wrist evaluation (PRWE) was used by Moloney et al. and Glogovac et al, whereby Glogovac et al. did not find a statistically difference between the two treatment modalities [7].Glogovac et al. also analyzed the outcome of Darrach resection.They found no statistical difference between this procedure and operative and non-operative treatment.However, the Darrach group (n = 5) had a PRWE score of 70, indicating severe functional disability.This was compared with a PRWE of 49 for non-operatively and 28 for operatively treated patients [7].Moloney et al., who also performed a subanalysis of isolated DUF, found worse PRWE scores for operated DUF patients [18].Patient rated wrist evaluation scores of 27.5 (standard deviation [SD] 36) were found for operated DUFpatients compared with 7.75 (SD 22) for the non-operative group (p = 0.01) The isolated DUF group had a PRWE score of 7 (SD 19) versus 18 (SD 41) for the DUF with concomitant DRF.

a b Fig. 2 8 a
The patient is placed in supine position with the arm fully abducted and resting on a mobile arm table.The wrist is fully pronated.Optionally the wrist can be slightly elevated to create a better angle of approach (example of elevating technique in .Fig.

3). b The surgeon
-Preoperative radiologic evaluation (including standard X-rays of the injured and unaffected side as well as computed tomography scan) to determine fracture pattern, stability and DRUJ involvement, ulnar variance and DRUJ congruency -Preoperative admission of 2 g cefazoline intravenously within 60 min prior to incisionInstruments and implants

Declarations Conflict of interest
. L.X. van Rossenberg, B.J.M. van der Wall, N. Diwersi, L. Scheuble, F.J.P. Beeres, M. van Heijl and S. Ferree declare that they have no competing interests.For this article no studies with human participants or animals were performed by any of the authors.All studies mentioned were in accordance with the ethical standards indicated in each case.This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material.If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.KimJO, Koh YD (2016) Management of distal ulnar fracture combined with distal radius fracture.J Hand Surg Asian Pac Vol 21:155-160 11.Kim JP, Park MJ (2008) Assessment of distal radioulnar joint instability after distal radius fracture: comparison of computed tomography and clinical examination results.J Hand Surg Am 33:1486-1492