This present study introduced a novel osteotomy instrumentation (fretsaw, jig, cable passer hook) as a substitute tool while oscillating saw was unavailable in THA. As far as we know, this is the first introduced substitute device that requires low-tech cleaning and sterilization within an acceptable time frame and meets satisfying osteotomy results, as well as the functional requirements, in THA surgery.
Several studies have shown that long operative times are associated with perioperative complications. Prolonged operation time can increase the risk of blood loss and periprosthetic joint infection (PJI), which may be associated with extended hospital, financial hardship, and even hazard of mortality for patients [11–13]. In this study, the average osteotomy time was a little longer in the new osteotomy instrumentation group than it in the oscillating saw group, yet there was no significant difference in the total operation time between two groups. This osteotomy instrumentation was an efficient tool as an oscillating saw and did not prolong the entire operation time. Thus, this fully functional, detachable, and flexible instrumentation could be the ideal choice rather than the chisel for osteotomy when the oscillating saw is deactivated. Besides, complications have occasionally been reported during THA, which includes bleeding, soft tissue damage, and fractures [14]. The major sources of bleeding in THA are the ischiofemoral ligament and posterior labrum, bleeding may occur if the surgeon performs an aggressive femoral neck osteotomy using an oscillating saw [15]. The inadvertent penetration of the oscillating saw into the soft tissue leading to neurovascular branch damage may cause postoperative pain and neural and vascular complications, although the reported rate of severe damage is rather low [16]. Unlike the oscillating saw, which requires a force toward the bone and the tissues from above, the fretsaw is placed around the bone and directed away from the adjacent soft tissue through the bone. Thus, there is no risk of overshooting or surrounding tissue and trochanter damage during the osteotomy. In addition, this instrumentation resulted in a flat osteotomy surface with no risk of notch generation and fracture of the trochanter or contralateral femoral neck. Therefore, it may offer a safe method of femoral neck osteotomy with a reduced risk of trapping soft tissue and periprosthetic femoral fracture.
The major objectives of THA include postoperative improvement of self-reported physical functioning, pain relief, and quality of life [17]. In this study, improvement in the HHS and VAS was observed in both groups. There was no significant difference in the postoperative HSS and VAS between the oscillating saw group and the new osteotomy instrumentation group at the 6-month follow-up (P > 0.05). These results demonstrated that the new osteotomy device could be used as a novel osteotomy technique in THA, which had no influence on physical rehabilitation and pain subsided.
Besides, there are still great challenges for surgeons to deal with complicated hip joint disease caused by congenital disease, rheumatic disease, and other serious diseases [18]. In these cases, the fused hips are difficult to dislocate and reconstruct accurately. The surgeon may encounter a struggle with an inconvenient osteotomy position and a higher risk of neurovascular branch damage during the cutting process, which can prolong the entire operation time. With our newly designed instrumentation, the femoral head does not have to be dislocated prior to osteotomy, since the fretsaw could easily surround the femoral neck through the cable passer hook. In this case, the osteotomy can easily be performed in situ with no need to excessively release the soft tissues, which results in less bleeding, enhanced stability, and faster rehabilitation [19].
Over the decades, many researches have been conducted to explore and advance for THA. In the thousands of study topics in this therapeutic method, surgical methods, postoperative outcomes, and materials remain the major focus [20]. However, so far as we know, this study is the first to focus on the femoral neck osteotomy tool and introduces and evaluates whether this novel osteotomy instrumentation could accomplish the accurate femoral neck osteotomy during THA surgery. Our clinical data and follow-up outcomes show that the collaboration of the fretsaw, jig, and cable passer hook can accomplish a safe, minimally invasive, efficient, and precise femoral neck osteotomy.
Nevertheless, this study had several limitations. First, the small sample size of the study resulted in low credibility of conclusions. Second, the jig could not fix the femoral neck well, which required a reformative jig with acumination. Finally, patients with severe hip ankylosis, femoral neck fracture or deformity of the femoral neck were excluded.
Therefore, the study conclusions still require further verification. Osteotomy instrumentation needs to be modified to fit the surgery. Randomized controlled trials with larger sample sizes, higher quality, and a longer follow-up will be conducted to confirm the results. Third, the osteotomy tools in both groups were only used in patients with a relatively normal femoral neck. Patients with more severe deformity of the femoral neck or hip ankyloses were not included in this study.