RESUMEN
Objective:To investigate the effect of vector sum concept in fine-tuning posterior column screw channel via ilioinguinal approach for the treatment of bi-column acetabular fracture.Methods:A retrospective cohort study was conducted to analyze the clinical data of 42 patients with acetabular double column fracture admitted to Weifang People′s Hospital from July 2015 to May 2021, including 22 males and 20 females, aged 23-77 years [(49.3±16.3)years]. The ilioinguinal approach was used in all patients with the anterior column fixed with a plate and posterior column fixed with a lag screw. The vector sum concept was used intraoperatively to fine-tune the posterior column screw channel in 19 patients (channel fine-tuning group): namely, a 2.5 mm Kirschner wire was inserted into the bony channel of the posterior column screw under fluoroscopy of iliac oblique and obturator oblique positions; when the Kirschner wire was not located in the middle of the ischial ramus under single fluoroscopy, the vector only needed to be adjusted in one direction, with zero in the other direction; when the Kirschner wire was not located in the middle of the ischial ramus under fluoroscopy of both the iliac oblique and obturator obturator oblique positions, the sum of the deviation vectors in the two directions was calculated before fine-tuning. The vector sum concept was not used to fine-tune the posterior column channel screw in 23 patients (channel non-fine-tuning group). The time of posterior column screw placement, intraoperative blood loss, frequency of guide wire adjustment and fracture healing time were recorded and compared between the two groups. At 6 months after operation, the quality of fracture reduction and hip function were assessed by Matta score and Merle D′Aubigne-Postel score, respectively. The complications were observed.Results:All patients were followed up for 7-71 months [(35.7±8.5)months]. In channel fine-tuning group, the time of posterior column screw placement was (5.1±1.5)minutes, with intraoperative blood loss of (798.8±83.9)ml, frequency of guide wire adjustment of (1.8±0.5)times and fracture healing time of (12.4±3.2)weeks; while these parameters [(39.8±12.0)minutes, (1 119.3±172.0)ml, (5.6±1.6)times and (15.6±4.2)weeks] were significantly shorter or less in channel non-fine-tuning group ( P<0.05 or 0.01). There were no significant difference in the quality of fracture reduction and hip function between the two groups at 6 months postoperatively (all P>0.05). After operation, symptoms of lateral femoral cutaneous nerve was found in seven patients, superficial incision infection in two who was healed after debridement and dressing change, deep venous thrombosis of lower limbs in three. There was no significant difference in the incidence of postoperative complications between the two groups [channel fine-tuning group: 26%(5/19), channel non-fine-tuning group: 30%(7/23)] ( P>0.05). Conclusion:For bi-column acetabular fractures via ilioinguinal approach, application of vector and concept to fine-tune the posterior column screw channel is beneficial for rapid screw placement into the osseous channel, significant reduction of intraoperative blood loss and early fracture healing.