gms | German Medical Science

Objectives: When performing minimally-invasive hip arthroplasty, use of a surgical extension table is considered state of the art. Disadvantages of using an extension table are the difficulty in intraoperatively assessing the leg length and the extra time needed for trained personnel to move the leg during surgery. Our study's objective was to compare the intraoperative accuracy of prosthetic positioning during surgery with an extension table or a conventional operating table.

Methods: This retrospective study included data from medical records of 324 patients who underwent hip arthroplasty at a cantonal hospital in Switzerland from 2014 to 2016. All patients were operated in the same manner by a senior surgeon. Patients were grouped according to the type of operating table used - conventional table (T0) or extension table (T1). Cases were excluded if they underwent a bilateral operation, had hip arthroplasty to treat fractures around the hip or had revision surgery. Variables included in the analyses were basic demographics, operative conditions, and medical outcomes. Inferential analyses were performed in Stata (version 15) using the following tests: chi square, Fisher's exact, t-test or Mann Whitney U. The alpha level was set at p<0.05. The leg length was measured pre- and postoperatively with the mediCAD® planning tool.

Results: A surgical extension table was used in 161 (49.7%) patients. No significant differences in age, body mass index, gender or body side were found between the groups. A statistically significant difference in the median length of hospitalization days occurred (T0 = 7 [interquartile range (IQR) 6-8], T1 = 6 [IQR 6-7] p<0.0001). However, the median duration of the operative procedure was shorter in T0 (55 minutes [IQR 48-67] than in T1 (60 minutes [IQR 54-69]) (p=0.002) and the median blood loss during surgery was lower (T0 = 400 ml [IQR 300-500], T1 = 500 ml [IQR 300-600], p=0.0175). The median postoperative discrepancy in the leg length was less in the group with the conventional operating table (T0 =1 mm [IQR 0-3], T1 = 2 mm [IQR 0-4], p=0.0122). The only four dislocations occurred in T1 and 7% of the entire study cohort had complications (T0 = 9%, T1 = 5%, p=0.102).

Conclusion: We conclude that operating without an extension table achieves higher precision in terms of minimizing leg length discrepancy, lower blood loss during surgery, and shorter operative time.