The management of the terrible triad injuries is still challenging. Although surgical treatment is effective for the vast majority of patients medically suitable for operation, the high incidence of complication should not be neglected [16–19]. With the increasing knowledge of elbow mechanism and pathology of terrible triad injury, many studies have presented good radiological and clinical results [7, 9, 20]. Unfortunately, elbow stiffness is still a common complication, which severely decreases the patients’ quality of life [21–23]. Many factors may influence the treatment results of TTI, including the fracture type of radial head and coronoid process, the surgical incision, the time between injury and surgery and the degree of ligament injury [24–27]. Identifying the potential risk factors for elbow stiffness after surgery treatment of TTI may assist surgeons taking preventive measures and improving the treatment of theses serious injuries, but there have been little studies published so far.
The most important findings of our study were that time between injury and surgery > seven days and the presence of ipsilateral upper limb injury increased the risk of elbow stiffness after surgical treatment of TTI. In the present study, the time from injury to surgery longer than seven days was associated with more than nine-fold increase in the risk of elbow stiffness. Different studies have evaluated the timing of elbow operation and stiffness. In a retrospectively study, Hong et al [15] examined the heterotopic ossification after elbow fracture surgery and reported that the risk of heterotopic ossification increased 10.62 times when the time to surgery was more than seven days. In another study, Tunalı et al [11] evaluated risk factors for stiffness after distal humerus plating and found that patients with the time to surgery > seven days were more likely (2.59 times) to suffer elbow stiffness. Similarly, Lindenhovius et al [28] compared the acute and subacute treatment of TTI and showed that earlier management could obtain a better flexion arc. In addition, Wigger et al [29] reported that the risk of post-traumatic elbow stiffness increased 1.12-fold for each additional day until the definitive operation was underwent after the initial injury. In line with these studies, we observed that the longer time between injury and surgery could increase the risk of elbow stiffness after surgery treatment of TTI. This phenomenon could be attributed to the fact that the patients who underwent delayed surgery may have had more severe soft-tissue damage and needed more time for the swelling to subside so as to avoid the wound complications [30].
Concurrent ipsilateral upper limb injuries in this study were associated with nearly 12-fold increase in the risk of elbow stiffness when a considerable number of factors noted to be risk in previous studies were controlled. The ipsilateral limb injury has been considered as a risk factor for worse outcome in different orthopedic disorders [31, 32]. In relation specifically to terrible triad injury, the available evidence is scarce. In 2013, Wigger et al [29] investigated different factors associated with restrictive heterotopic ossification (HO) after elbow trauma and found that ipsilateral injury accounted for 37% of cases in restrictive HO group while only 28% in non-restrictive HO group. Although no significant difference was observed between the two groups, the trend was still worth noting that the ipsilateral injury potentially affected the range of elbow motion. Additionally, Allemann et al worked on the predictive factors of complication and adverse outcomes in 149 patients with isolated or combined fractures in ipsilateral upper limb [33]. They found that, compared with the isolated articular fracture group, the combined fractures group was more likely to occur joint contractures (25% vs 8.3%, p = 0.009) and severe heterotopic ossifications (80.7% vs 13.6%, p < 0.001). In another study, Dickens et al [34] reported that periarticular fractures on both sides of the elbow, which defined as bipolar fractures were significantly associated with deceased range of elbow motion and worse outcome in patients with open elbow fractures. In any case, the multiple injuries in the ipsilateral upper limb always reflected greater soft tissue injuries and a more serious injury. The serious soft tissue injuries and concurrent ipsilateral limb fractures, often requiring a delayed surgery, prolonged operation course and longer time of immobilization after operation, may explain the elbow stiffness after surgical treatment of TTI.
The present study has also supported the previous literatures reporting the association of high-energy injury and elbow stiffness. In a retrospectives study, Zheng et al [35] retrospectively investigated 169 patients with elbow stiffness and noted that the risk of sever elbow stiffness was markedly higher in high-energy trauma group (OR 4.45, p = 0.03). Dickens et al [34] reviewed 136 patients with open elbow fractures and found that high-energy injury was associated with limited range of elbow motion. This is not surprising, given the association between injury mechanism with the degree of osseous and soft tissue damage-that is, the higher the force, the more serious osseous and soft tissue injury and the more likely to develop elbow stiffness.
On the contrary, our study has not found support for the different managements of radial head fracture as a risk factor of elbow stiffness. Yan et al [36] analyzed 39 patients with terrible triad injury who were treated with either radial head reconstruction or radial head replacement and found that the rate of elbow stiffness was significantly higher in repair group than replacement group (21.1% vs 5%). In a recent study, Ostergaard et al [14] investigated 62 patients who had surgery for TTI and found that elbow stiffness was the most common indication for reoperation (21%) and radial head treatment was the only risk factor for reoperation. However, the most important difference with reports indicating a positive association of radial head treatment and elbow stiffness, is that the injury mechanism was controlled in our study. The high-energy injury often resulted in comminuted radial head fractures, which were difficult for open reduction and internal fixation and always required radial head replacement for early rehabilitation.
There are several limitations in our study. First of all, because of the retrospective nature of the study, selection bias was unavoidable. But, after carefully selected patients according to the inclusion and exclusion criteria, the readers could be able to identify which cases our results best apply. Secondly, the study was performed nearly a seven-year period in two hospitals and the operations were conducted by several different surgeons, all of which might result in potential selection bias. However, considering these operations were all performed by experienced surgeons in the tertiary-care referral centers and the principle of dealing with terrible triad injury remaining constant, we believed that these were not a relevant limitation of the present study. Thirdly, the sample size of patients was relatively small, which would limit the number of risk factors evaluated. In future, a lager sample size, multi-center study with a high level of evidence should be conducted to further verify our findings. However, despite these limitations, to our knowledge, this is the first study to perform a detailed risk factor analysis for elbow stiffness after surgical treatment of TTI. Knowledge of these risk factors will be valuable in improving the treatment of terrible triad injury.