The elbow is more susceptible to motion loss than any other joint after trauma [20, 21]. The aim of treatment for elbow stiffness due to trauma, is to achieve a functional range of movement and a pain-free, stable joint [1,2,3,4, 22]. The disorder can be treated nonoperatively or surgically. A failed trial of non-operative therapy is a strong indication for performing a surgical release [2,3,4]. Depending on the operating surgeon’s expertise level in elbow arthroscopy, status of the ulnar nerve, formation and location of HOs, extent of the contracture, and articular surface damage, arthroscopic techniques may be preferred to relieve simple contractures [23, 24]. Therefore, an open arthrolysis is the most commonly reported, traditional treatment method [2, 25, 26], using which, a mean ROM of 103° (Range: 85°–129°) and a mean gain of 51° (Range: 38°–60°) have been achieved, with a mean complication rate of 23% (Range: 0–59%), as reported in a systematic review of 637 operated patients across 21 different studies .
There is a lack of evidence regarding the optimal time interval from the time of injury after which, a surgical release is indicated. Older studies have advocated a longer waiting time of 12–24 months (from injury to operation), in order to ensure the maturation of bone and reduce the recurrence rate. However, these studies have ignored the progressive fibrosis of the surrounding soft tissues, like capsules, collateral ligaments, and muscles, during this waiting period . Muscle atrophy can also appear when range of motion at the elbow is limited over a long period, which would negatively impact the postoperative rehabilitation program, wherein active cycles of flexion-extension and forearm rotation exercises are encouraged and are required to be performed by each patient [28, 29]. Patients with symptoms of ulnar nerve motor dysfunction (with or without disability) will be at a higher risk of aggravation of the nerve injury due to ischemia and compression, caused by a constant dysfunctional extension at the elbow, or following continuous pressure from a surrounding HO [30, 31]. The articular cartilage also deserves special attention, as it could be damaged and destroyed when the elbow is immobilized, or limited to a small ROM, or hinged acting with an abnormal articular surface or structure (such as trochlea) over a long period [32, 33]. Such degradation of the articular cartilage would contribute to secondary joint arthrosis, which in turn, will further aggravate elbow stiffness, pain, and instability. Additionally, a long-term stiffness of the elbow would significantly inconvenience patients in their daily activities and has a great negative impact on the quality of life [34, 35]. Most patients would want to resolve this issue as early as possible.
Sun et al. found in their systematic review of 27 studies with 836 patients, published between 1989 and 2017 that the patients operated earlier (surgical timing: 6–10 months) achieved the highest mean gain in ROM (71°, from 39° preoperatively to 110° at the final follow-up), which was higher than that achieved by the patients operated at 11–20 months (62°) and at > 20 months (58°), respectively. The mean rate of complications was also lower in the group operated earlier (17.0%), as compared to the median (22.7%) and the long (21.4%) interval groups. However, the statistical significance of these differences was not analysed in their study. They recommended an early surgical release, so that the patient could have a shorter rehabilitative period and could return to work earlier . The results of our study are similar. There were no significant differences in postoperative elbow ROM (p = 0.067), MEPS (p = 0.350) and its score ratings (p = 0.329), pain level (p = 0.227), ulnar nerve symptom (p = 0.187), and individual complication rates (all p values > 0.05), among the three ER, MR and LR groups. This meant that an early arthrolysis would not negatively affect postoperative elbow motion capacity and functional outcome. Also, the risk of postoperative complications would be the same as with a late arthrolysis procedure. In another relevant study, Haglin found that patients who achieved an ROM of at least 100° postoperatively had a significantly shorter mean time interval from initial injury to initial arthrolysis than in those who had failed to achieve a similar ROM (35 vs. 103 weeks, p < 0.0005) . Koh also reported that the time from the initial injury to surgical release, with a cut-off value at 19 months, was the only independent factor affecting the final elbow ROM . More importantly, Zheng reported that a long period of elbow stiffness (> 5 years) could negatively influence the functional outcome (MEPS, p = 0.016) and increase the risk of complications (p = 0.002) after a subsequent arthrolysis.
Traditionally, surgeons waited for at least 1 year after initial trauma to intervene surgically, due to a high risk of recurrence of HO . Recent studies have however, reported good results following an early excision (at < 1 year) with no difference in the HO recurrence rates as compared to a delayed surgery [7, 38]. Chen retrospectively reviewed 164 patients with HO, who underwent open arthrolysis, and divided them into two groups, with the HO excision performed at an average 23.0 months after initial injury (range: 9–204 months) and an early excision group, who underwent the excision procedure at average 6.1 months (range: 3–8 months). They finally found no significant difference between the two groups with respect to postoperative ROM, MEPS and complications, especially for HO recurrence (p = 0.942) . Similarly, in our study, no significant difference in HO recurrence (p = 0.275) was found among the three groups. The HOs generally mature in approximately 3 to 6 months , and based on our findings, we would recommend an early excision at 6 to 10 months after the initial injury. However, it is important to wait until a mature HO, with well-demarcated cortical margins and trabeculations is observed radiologically, and signs of new bone formation such as pain, local tenderness, swelling, and hyperaemia have resolved. A careful management of the HO intraoperatively with an appropriate postoperative rehabilitation regimen (rather than implementing stressful and violent exercise), is essential.
For now, there is a consensus that non-operative treatment should be attempted for at least 6 months, before considering an operative modality [2,3,4]. Non-operative treatment methods like dynamic or static progressive splinting may be effective, possibly due to the mechanism of soft-tissue relaxation. In patients with a relatively mild contractures, following an elbow injury sustained < 6 months back, there has been a reported improvement of 35–50° in elbow ROM with conservative management . Currently, the utilization of an active or passive stretching of the elbow during exercise is under debate. Several authors have discussed the use of CPM (Continuous Passive Motion) devices in the postoperative phase, to prevent recurrent elbow joint stiffness [22, 41, 42]. Although there are concerns that passive-aggressive elbow exercises may lead to an increased likelihood of heterotopic bone formation, there is little evidence to clarify the relationship between passive motion and HO. We advise that passive range of motion exercises should be performed progressively, and under supervision, with a low load and within tissue tolerance. The patient should be relaxed and should not experience much pain when passive stretching is applied to the elbow. During the preoperative period, we always advise patients to keep on attempting to practice the elbow ROM and forearm rotation by bouncing a ball actively, by taking the affected elbow up and down by themselves, and rolling it forward and backward. A violent training is forbidden while performing a rehabilitation program in case of HO occurrence.
In addition to the retrospective nature of the study, the relatively heterogeneous case series (due to a low prevalence of elbow stiffness) and the fewer number of patients analysed were also limitations, which made more meaningful statistical comparisons among the three groups (especially with respect to complications) difficult. The intra-group (pre- and post-operatively) and inter-group (3 groups post-operatively) evaluations of the elbow muscle and grip-strength were not included in this study, which was also a limitation.