Introduction

Acetabular fractures demonstrate an overall incidence of about 2–8% of all fractures and may rapidly lead to long lasting physical limitations and functional disability [1]. Regarding internal fracture fixation, various surgical access strategies such as the ilioinguinal approach, the Kocher–Langenbeck approach and the Stoppa approach have proven to be effective. However, sufficient visualisation of the fracture site to achieve anatomical reduction is always a challenge in these approaches which could have a significant impact on the functional outcome [2]. In this context, the less invasive anatomical pararectus approach suggests an alternative access route to surgically stabilise displaced acetabular fractures. Its anatomical tissue-conserving shape protects important functional structures and demonstrates particular advantages in terms of visualisation compared to other approaches. This allows better possibilities for anatomical fracture reduction, achieving a step-free reduction in more than 90% of cases [3]. Radiological evaluation also showed a comparable outcome with other minimally invasive surgical procedures while achieving shorter operation time [4, 5]. In this context, a significantly improved reduction in joint space with similar complication rates was found, when the pararectus approach was compared to the ilioinguinal approach [6]. A crucial aspect in the rehabilitation process following comminute acetabular fractures is the early recovery of mobility. Current surgical interventions that require extensive dissection of major hip muscles demonstrated to have a negative impact on walking quality [7, 8]. Although the pararectus approach indicates to be a promising anatomical access to address acetabular fractures involving the quadrilateral plate, clinical studies on the early postoperative biomechanical outcome and functional mobility are still missing. Instrumented gait analysis can serve as a viable quality tool in the objective assessment of human movement in a clinical setting [9]. In so far, acetabular fractures using the anterior ilioinguinal or the posterior Kocher–Langenbeck approach demonstrated incomplete recovery of hip and pelvic biomechanics including limited mobility and an altered functional outcome after surgery [10,11,12]. However, most of these gait studies examined patients more than 12 months after surgery, and the immediate postoperative result, therefore, is only partially reflected. The pararectus approach is expected to result in less muscle damage and due to its minimally invasive character it is intended to achieve an early and fast recovery after surgery [13, 37]. Using a patient adjusted walking speed for our matched controls would have been beneficial for data comparison. Another limitation of this study is that no biomechanical long-term adaptions using the pararectus approach were investigated. However, the main study aim was to evaluate gait restoration during the early postoperative phase (up to 6 months after surgery) where full weight bearing is regained and supervised physical therapy is completed. Since no group comparisons regarding other surgical treatments were performed in this study, we also cannot directly state whether the pararectus approach provides a significant advantage to other treatment strategies. In this context, a systematic comparison might be suggested in the future.

Conclusion

Patients with isolated unilateral acetabular fractures treated using the pararectus approach showed an almost physiologic dynamic joint mobility of the lower extremities and clinically demonstrated a good hip function. However, reduced joint moments and vertical ground reaction forces during walking and stair descend indicate that deficits in weight bearing capacity and dynamic motor control are still present. In this context, a diminished self-reported physical and mental state compared to healthy controls was also observed. Nonetheless, our findings confirm that lower extremity joint mobility during walking and stair climbing can recover in a very early phase after surgery. Thus, the less invasive pararectus approach appeared to be a viable treatment strategy of acetabular fractures to achieve a promising functional baseline for the ongoing rehabilitation process.