A total of 189 patients underwent elbow surgery during the study period, of whom 38 had been treated with a hinged elbow fixator. Four patients were excluded; two patients were treated by another department without consultation of a dedicated elbow trauma surgeon and in two other patients the fixator was removed in another hospital. A total number of 34 patients with a median follow-up of 13 (P25-P75 = 8–21) months were analyzed (Fig. 3). 24 (71%) operations were performed by a surgical team that was classified as experienced and treated 8 patients (89%) with a simple elbow dislocation and 16 (64%) patients with a complex dislocation. The hinged external fixator surgery was performed a median of seven (P25-P75 = 0–20) days after trauma and was removed a median of 48 (P25-P75 = 42–57) days later.
An overview of patient and injury characteristics, with a subdivision into simple and complex dislocations, is shown in Table 1. The median age was 49 (P25-P75 = 29–61) years in a predominantly male cohort (n = 20, 59%). Twentyfive (74%) patients suffered a complex dislocation, of which 21 were managed acutely. In 19 (56%) patients, the mechanism of injury was valued as low energy.
Nine (26%) patients developed one or more fixator-related complications and eight (24%) patients required one or more secondary interventions due to these fixator-related problems (Table 2). Only one patient with a simple dislocation developed a complication and required a secondary intervention, being a joint incongruence for which the fixator was realigned. The other eight patients all had a complex dislocation. The complications in this group were pintract infections (n = 6 patients), redislocation (n = 1), muscle hernia (n = 1) and hardware failure (n = 1), for which treatment with antibiotics (n = 1), incision and drainage (n = 4), fixator realignment (n = 1) and fixator exchange (n = 2) was carried out.
Non-fixator injury-related complications encountered were elbow stiffness (n = 6), ulnar nerve entrapment (n = 4), arthrosis (n = 2), heterotopic ossification (n = 2), joint crepitus for which radial head screws were removed (n = 2), wound fistula (n = 1), and joint incongruency that was solely related to the trauma and had nothing to do with the hinged external fixator (n = 1). For these non-fixator injury-related complications, 11 patients required one or more re-interventions.
An overview of data regarding presence of severe pain and limitations in activities of daily living and work/sports is presented in Table 3. None of the patients reported severe pain at the end of follow-up. Only two patients, with a complex dislocation, required pain medication at discharge. Two patients with a complex dislocation experienced restrictions in ADL and work at the end of follow-up.
The median range of motion of the total cohort at the last patient visit was 140° flexion (P25–P75 = 120°–145°), 15° constraint in extension (P25–P75 = 10°–23°), 90° pronation (P25–P75 = 90°–90°), and 80° supination (P25–P75 = 56°–90°).
A subanalysis showed that 24 (71%) patients were treated by an experienced surgical team, of which only 3 (13%) developed a fixator-related complication and 3 (13%) underwent a secondary intervention. The other ten (29%) patients of this cohort were operated by a general surgical team: six (60%) of them faced fixator-related complications and five (50%) required a secondary intervention.
The most important finding of this study is that applying a hinged elbow fixator in patients with a simple or complex elbow dislocation yielded—although the injury was severe—excellent range of motion: the median arcs of flexion–extension and pronation-supination were 125° and 170°, respectively. The hinged elbow fixator was applied for both acute management and as revision surgery to treat joint incongruency or a stiff elbow. Retrospectively, 34 patients were included over a period of 12 years, which provides one of the larger cohorts in literature regarding the use of hinged external fixators for elbow dislocations.
Data from this study present excellent outcomes with only a small rate of complications (26%) and few patients with persisting pain or severely limitations (6%), which is in line with current literature. In the series of Hopf et al., one out of 26 patients reported mild resting pain and six patients reported moving pain . Iordens et al. showed median pain scores (VAS) of 0.5 (P25–P75 = 0.0–1.9) at one year follow-up . Hackl et al. showed that early mobilization enables patients to return to work earlier; however, the number of patients limited in their activities of daily living, work or sports were not reported .
Due to a lack of comprehensive understanding of the pathogenesis of elbow stiffness, outcomes after the treatment of elbow dislocations are often unsatisfying. The attempt to maintain stability by prolonged immobilization produces a high rate of post-traumatic stiffness [1, 6]. According to several studies, the treatment with a hinged external fixator is an effective supplement to open reduction and internal fixation (ORIF) to improve ligamentous and articular stability as well as the range of motion after an elbow dislocation [6, 7]. Active and passive motion with slow stretching of the elbow during the early postoperative period is crucial in postoperative physical therapy to prevent the emergence of heterotopic ossification, which is seen in up to 75% of the cases [12, 19, 20]. An important determinant for a favorable clinical outcome is the compliance of the patient . If the patient does not cooperate postoperatively, even a good surgical result with anatomic reduction and reconstruction of the joint may lead to an unfavorable clinical result. Therefore, it is important to involve a dedicated rehabilitation team in the postoperative treatment of these patients, who—in our setting—started directly in week 1 after surgery and continued until progression in function was limited.
Because correct mounting the external fixator is technically demanding, the presence of an experienced surgical team was included in the results. In the hands of the experienced surgeon, even complex fracture dislocations of the elbow or their sequelae can be sufficiently reconstructed, which allows a good clinical outcome [1, 14].
A qualitative functional range of motion of the elbow was considered as > 120° flexion and a minimal flexion–extension arc of > 120°. An open arthrolysis, indicated by a stiff elbow, was performed in a patient whose ROM was less than functional. Ahmed & Mistry considered an arc of motion of less than 30° to 130° in a joint that is unresponsive to bracing and therapy as a stiff elbow and therefore as an indication for capsulectomy . Kuhn et al. proposed a capsulolysis if there is a limitation of 30° or more in extension . Treatment with a hinged external fixator was not part of their management. No other studies report on specific ROMs as indication treatment of elbow stiffness.
Other studies regarding hinged external fixators analyzed up to 27 patients [3, 10, 12, 22, 23]. With 34 included patients in the current series, it is among the largest cohort studies to report range of motion for hinged external fixators as a treatment in elbow dislocations to date. Cheung et al. included 100 patients, however, they reported only on the complications of hinged external fixation .
The hinged external fixator was applied as soon as possible after trauma or after diagnosing persisting instability as a result of extensive arthrolysis for stiff elbow. The fixator was removed after 6–8 weeks, predominantly. This was consistent with other studies [3, 12, 22, 23].
Regarding the range of motion, only one study showed better range in the flexion–extension arc . However, this study exclusively analyzed patients with a simple elbow dislocation. In any of the other published studies, range of motion was inferior to the data presented in this study [3, 10, 20, 23]. The excellent functional results presented, despite serious injury with mostly complex dislocations, might be related to a team with great dedication regarding not only the surgical stabilization of the joint, but also the compliance of postoperative exercises (with the help of a dedicated physical therapist), which is on of the main determinants for a good elbow function. Due to the surgical technique we used, all patients were allowed to have full functional recovery by unrestricted motion exercises postoperatively. The only limitation regarding range of motion was caused by pain, which could be treated sufficiently with painkillers.
The fixator-related complication rate in the current study was 26%, which is low compared with other studies, that report rates ranging between 37 and 57% [3, 10, 22, 23]. Hopf et al. reported a complication rate of 23%, which is comparable to the current results . Only Sakai et al. showed fewer fixator-related complications: 17% . It is tempting to speculate that this might be due to the fact that all procedures were performed by the same surgeon. Cheung et al., who included 100 patients and specifically reported on the complications of hinged external fixation by 2 surgeons, found that 15% of the patients developed minor complications and 10% developed major fixator-related complications . The authors abandoned the use of dynamic external fixators due to these numbers and due to the difficulty of identifying and maintaining the true joint axis.
The possible superior results in the current study together with studies in which only one or two surgeons are involved compared with other studies might suggest that surgeon experience could have contributed to a lower complication rate [9, 20]. This conclusion is supported by the subanalysis that shows less complications in the patients treated by an experienced surgical team. Based on this, results may benefit from centralizing applying a hinged external fixator. A larger hospital volume further reduces morbidity and mortality . Our results hint that an experienced surgical team with better familiarity to this specific treatment can achieve better results.
The most important limitations of the present study are the retrospective nature and the relatively small number of patients included. The follow-up in this study ended when the patient was discharged from outpatient visit. No reliable statements can be done regarding ROM, complications or re-interventions in the period after the last visit to the hospital.
Although we realize that we included a heterogeneous group of patients (acute management of simple and complex elbow dislocations and revision surgery for joint incongruency or stiff elbow), the indication for elbow fixator placement was the same for all patients: creating joint stability and allowing for early active mobilization to improve outcome.
A hinged elbow fixator applied by a dedicated elbow surgeon in cases of elbow instability after elbow dislocations can result in excellent joint function. Fixator-related complications are mostly mild and only temporary. The results in the current study suggest that surgeon experience may have contributed to a lower complication rate. Based on this, results may benefit from centralizing applying a hinged external fixator.