We have modified and standardized the technique of minimally invasive operative treatment of intra-articular calcaneal fractures using the 2-point distractor through changes in positioning of the patient, intraoperative radiological viewing, screw placement adjustments, and postoperative care. We believe that this technique should be preferred over ORIF. The main advantage of this technique is the reduced rate of wound complications (2.7%) compared to ORIF (16.7%) in our study population. Another important benefit is the possibility of performing the procedure immediately without waiting for consolidation of the soft tissue. This primarily affects the patient since an immediate operation reduces the pressure on the soft tissue and consequently reduces the level of pain, and it is also of socioeconomic interest as the duration of hospitalization is reduced due to less post-operative swelling. Last but not least, the overall arthrodesis rate of 4.7% at the Traumacenter Linz is comparable to the literature, although we treat all types of fracture morphologies via minimally invasive means, regardless of the amount of comminution. Also, if necessary, a secondary arthrodesis is technically easier to perform after minimally invasive procedures.
Many studies have been published concerning the optimal method of treating intra-articular calcaneal fractures. (1–3,6,9,11–15) Most of them lacked a representative number of patients, and therefore, a general consensus is still undetermined. (1,2,14)
At the Traumacenter Linz, the demographic analysis revealed relatively young patients (mean 43.3 years) which reflects the high socioeconomic influence of this fracture occurrence. Also, there is a male predominance of 3.8:1 in the study cohort. Causes of injury were high-energy trauma in the majority of patients. In accordance with the international literature, falls from heights are the most likely causes of injuries.(16) Contrary, Alexandridis et al. (17) and Bohl et al. (18) reported a lower incidence of falls, but a higher rate of traffic accidents (49%).
Open reduction and internal fixation (ORIF) has been the preferred therapy for intra-articular fractures in recent decades. (1,2) The generally accepted approach for visualization of the fracture site is the extended L-shaped lateral approach, which is considered the gold standard. (1) Independent of the approach in ORIF, a consolidation of the soft tissues is recommended. (2,5,19) However, it can take 2-4 weeks before the so-called "wrinkle-sign" occurs and swelling decreases. (2,5) Al-Mudhaffar et al. reported an increased incidence of wound healing problems when the operative procedures were performed within the first week post-injury in an open setting. (19) Rammelt et al. concluded that an operative intervention after two weeks also increases the complication rate, which could be explained by increasing fracture consolidation prior to surgery and a resulting need for higher force with reduction. (5) In our proposed technique, the surgery is intended to be performed within the first three days after injury. Even in cases with edematous tissue, our method did not lead to an increase in wound healing disturbances. The earlier the surgery was performed, the easier the mobilization of the fragments became.
To overcome problems with wound complications, wound infections, and skin necrosis specifically, many minimally invasive methods to reduce and fix calcaneal fractures have been proposed. (15) At the Traumacenter Linz, this rate was 2.7% using the 2-point distraction method. We believe this is not only a consequence of the operative technique, but also a result of early surgical intervention with hematoma evacuation, reduction, and stabilization thereby leading to a decrease in internal pressure.
In a meta-analysis, Fan et al. compared the clinical results after minimally invasive techniques to those after ORIF. The study reported a lower soft tissue complication rate, and reduced duration of the operative procedure itself. Also, functional results were almost equivalent for the two groups. (13)
The minimally invasive technique has become a standardized procedure at the Traumacenter Linz, and about 86% of all operatively treated fractures have been utilized in the 2-point distractor technique.
Comparisons between the different methods of minimally invasive techniques and ORIF methods are difficult due to a lack of standardized measures, different techniques, and a low number of patients. (12,15,20,21)
Wallin et al. published a systematic review on the clinical results after minimally invasive techniques used to treat calcaneal fractures. The functional results after Sanders type II-IV compared with ORIF were promising, although most of the studies had low levels of evidence. Soft tissue complications and duration of the procedure were lower in the minimally invasive group. They did not discuss whether minimally invasive techniques or ORIF led to better anatomic reductions and functional results. (15)
In a randomized controlled study, Kumar et al. found a lower rate of wound healing problems, and better functional outcomes in the minimally invasive group compared with those after ORIF. The authors postulated, that better functional outcomes can be explained by a lower wound complication rate and a better anatomical reconstruction. (22) In terms of anatomic reconstruction, ORIF is still considered the goldstandard for intra-articular fractures. (1,2,9,13)
In 2007, Schepers et al. presented their results on minimally invasive methods with a follow-up of three years. Functional results after minimally invasive techniques were lower compared to those reported after ORIF. The infection and wound complication rates were similar to those of ORIF. Subtalar joint motion could be restored to nearly 70% compared to the uninjured side. The secondary arthrodesis rate was higher than in Buckley’s study from 2002. (23,24)
The most crucial factor for gaining a satisfactory result, according to Veltman, is the absence of complications. (1) Also, other authors concluded that the best results were achieved when both, the operative procedure, and aftercare were complication-free. (2,3) Patients with comorbidities such as vascular diseases, diabetes, and nicotine abuse are more prone to these perioperative complications. (2) Also, patients over the age of 60 years are more likely to be affected by postoperative complications and subtalar arthritis, although this may be linked to the higher rate of comorbidities in elderly. (2)
The published rate of arthrodesis is between 0 and 15% after minimally invasive surgery, 0-12% after ORIF, and 3.8-17% after conservative means. (23–32) The subtalar arthrodesis rate of 0% described by Park et al. was based on a relatively low number of patients and only one year follow-up. (29) In extremely complex intra-articular fractures, a primary subtalar arthrodesis is deemed the method of choice to achieve satisfactory results in the given situation. (2)
The secondary subtalar osteoarthritis rate requiring arthrodesis after minimally invasive techniques was 4.7%. Between 2007 and 2015, this arthrodesis rate was almost constant. No primary subtalar arthrodesis was performed in our group of patients. The secondary arthrodesis rate of 4.7% after operative intervention in our study is comparable to the current body of literature. In a study published by Buckley et al., 37 of 218 (16.9%) patients required an arthrodesis, and 7 of 206 operatively treated patients (3.4%) required a secondary operative intervention. (33) More prospective randomized studies with longer follow-up periods are required to compare the results of minimally invasive techniques with ORIF and conservative treatment.
After conservatively treated calcaneal fractures, a 6-fold higher likelihood of arthrodesis has been published compared to primarily surgically treated patients. Furthermore, patients with Sanders Type IV, and patients with a Boehler angle of 0 degrees had a notably increased risk of secondary subtalar arthrodesis. (34) In general, operative reconstruction of calcaneal fractures provides a better tissue situation in cases which require a secondary subtalar arthrodesis thereby also leading to better long-term results. (9)
Previous literature reported, that functional results after minimally invasive treatment are equivalent to those of ORIF. (35,36) Based on these functional results, together with lower complication rates, two recent studies have argued that minimally invasive techniques are considered superior to open techniques in the treatment of intra-articular fractures. (13,15)