There has long been conflicts regarding clinical relevance in fixation of ulnar styloid fractures. A recent meta-analysis revealed functional scores favoring distal radius fractures without concomitant ulnar styloid fractures while the outcome difference was not significant in patients with and without ulnar styloid fractures [14]. In literature review, most of those studies anecdotally evaluated ulnar styloid fractures based on the outcomes of concomitant distal radius fractures and commonly introduced bias assuming more complicated presentation in surgical treated ulnar styloid fractures than non-surgical cases to reach a conclusion of no significant difference [15]. Besides, surgical concerns existed almost uniquely in styloid base fractures owing to both fixation feasibility [7] and cadaveric demonstration [16]. However, wrist function could be adversely affected in several additional ways such as fracture line extension, disruption of secondary stabilizers, and associated TFCC injury [17]. Principles of management may include anatomical restoration, fracture fixation and TFCC repair. Our previous study suggested early fixation of ulnar styloid fractures to yield better outcome than late surgery [18].
In comparing patient characteristics between two groups, significant difference was only noted in the item of concomitant DRF; significantly higher incidence was noted in group B than group A (p = 0.034). It may reasonably correspond to the common concerns of ulnar styloid base fracture in surgically treated cases as well as cadaveric research. In contrary, presentation of styloid tip avulsion in fracture orientation and fragmentation was insufficiently defined and generally overlooked even if there was concurrent DRF and DRUJ instability. There were 10 cases of concomitant DRFs in our study. All except one were chronic ulnar styloid fractures, which underwent subsequent surgical fixation owing to persistent ulnar wrist pain and decreased range of motion while the concomitant DRFs had been well reduced and fixed with locking plates. The case with acute injury was presented in Figure 2; surgical fixation of ulnar styloid base fracture was performed simultaneously since remarkable DRUJ laxity was noted following double plating of the DRF. In addition to the commonly mentioned styloid base fracture, we presented difference fracture patterns and proposed an innovated fixation option with favorable treatment outcomes.
Being a morphological categorization, Gaulke classification was proposed to further divide the ulnar styloid fractures according to fracture location and orientation [12].
Fracture displacement was found to independently affect healing of ulnar styloid in different fracture patterns. Given a wide range of nonunion rate in ulnar styloid fractures [19], Gaulke classification established a morphological categorization with predictive value to serve a guidance for treatment. In our series, four cases in group A were classified as B Gaulke B types; two were IB and two, IIB. The remaining six cases included one IA, three IC and two 2A. However, the fracture pattern in the two cases classified as IIB was identified from lateral view (Fig 3) instead of anteroposterior view that was originally defied in Gaulke classification. Owing to the diversity of fracture patterns, we emphasize that meticulous radiographic survey in different projections is crucial to facilitate correct diagnosis and proper management. On the other hand, the majority of group B were categorized as 2A (13 cases) and 2C (seven cases); only one case was 2B. In the index surgery for group A, fixation using small anchors allowed those tiny fracture fragments in group A to be sutured and fixed back to distal ulna, and yielded comparable outcome to tension band wiring of styloid base fractures in group B. In spite of slightly better functional results based on MMWS and QuickDASH in group B than A, the difference was insignificant.
Excision of bony fragment plus transosseous tissue repair has been recommended in two studies [6, 8] in symptomatic ulnar styloid avulsion fractures with small bony fragments. A recently published cadaveric study further documented the location and importance of ulnar collateral ligament around the ulnar styloid [20] in addition to TFCC and capsular insertion traditionally mentioned in the literature. Refined small anchors with double-loaded ultra-braid suture allowed avulsion bony fragments to be sutured back feasibly and efficiently while traditional transosseous suture techniques still could serve as an augmentation by securing regional tissue and capsule to the distal ulna.
The incidence of surgical complication was comparable for both groups. Nonunion and residual DRUJ instability was slightly more common in group B. Radiographic resorption of ulnar styloid fragments was observed in both groups. None of those patients presented symptomatic instability and received revision surgery. Implant-related complication rate was significantly higher in group B (p = 0.021). Symptoms of implant irritation or migration with subsequent removal surgery were commonly seen in group B, but none was in group A. Local discharge around the percutaneous Kirschner wire for DURJ fixation was noted only in one patient of group A, and soon subsided with wire removal. None in group A exhibited migration or loosening of suture anchor and underwent secondary surgery.
The main limitations of this study include small cohort number and heterogeneity of fracture characteristics. Analysis of trauma mechanism with correlation to functional outcome is not allowed based on retrospective reviews of medical records. In addition, a follow-study is necessary to elucidate the long-term effect of the index surgery on wrist function and DRUJ sequelae.