CT based PSI blocks for osteotomies around the knee provide accurate results when intraoperative imaging is used

Abstract

Purpose Correction osteotomies around the knee are common methods for the treatment of varus or valgus malalignment of the lower extremity. In recent years, patient specific instrumentation (PSI) guides were introduced in order to enhance the accuracy of these procedures. The purpose of this study was to determine the accuracy of CT based PSI guides for correction osteotomies around the knee of low volume osteotomy surgeons and to evaluate if CT based PSI blocks deliver a high degree of accuracy without using intraoperative fluoroscopy. Methods Two study arms with CT based PSI cutting blocks for osteotomies around the knee were conducted. Part one: A retrospective analysis of 19 osteotomies was made in order to evaluate the accuracy in the hands of a low volume surgeon on long-leg radiographs. Part two: A cadaveric study with 8 knees was performed for the purpose of analyzing the accuracy without using intraoperative fluoroscopy on pre- and postoperative CT scans. Hip-Knee-Ankle angle (HKA), lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were analyzed. The mean absolute delta (∂) between the planned and postoperative parameters were calculated. The accuracy of both study arms were compared. Results Part one: The mean MPTA ∂, LDFA ∂ and HKA ∂ was 0.9°, 1.9° and 1.5°, respectively. Part two: The mean MPTA ∂ and LDFA ∂ was 3.5° and 2.2°, respectively. The mean ∂ of MPTA is significantly different between clinical patients with fluoroscopic control and cadaveric specimens without fluoroscopic control (P < 0.001). All surgeries were performed without complications such as a hinge fracture. Conclusion The clinical use of PSI guides for osteotomies around the knee in the hands of low volume surgeons is a safe procedure. The PSI guides deliver a reliable accuracy under fluoroscopic control whereas their non-use of intraoperative fluoroscopy leads to a lack of accuracy. The use of fluoroscopic control during PSI guided correction osteotomies is highly recommended. Level of evidence IV – Retrospective and experimental Study

Custom-Made Devices Represent a Promising Tool to Increase Correction Accuracy of High Tibial Osteotomy: A Systematic Review of the Literature and Presentation of Pilot Cases with a New 3D-Printed System

“…An additional study was excluded because it investigated the osteotomy procedure to correct tibial plateau fractures’ non-union [ 12 ]. A total of 28 articles [ 6 , 7 , 8 , 9 , 10 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ] were included in this systematic review ( Figure 1 ).…”

“…Among the included studies, 19 were human studies, four were cadaveric studies, and four were technical notes. One study [ 32 ] presented both a human and a cadaveric series. A medial opening wedge osteotomy surgical technique was described in 26 out of 28 presented studies.…”

“…Regarding to the PTS, the difference between the achieved sagittal alignment and the target was lower than 3° in all the included studies. Among the cadaveric studies, the difference between the target and the obtained MPTA angle was under 1° except in one study [ 32 ] where intraoperative fluoroscopy was not used.…”

“…Five studies [ 8 , 20 , 28 , 29 , 35 ] reported the duration of the surgery, revealing an average surgical time between 26.3 and 61 min. Seven studies [ 8 , 20 , 21 , 28 , 29 , 32 , 35 ] reported the mean intraoperative fluoroscopy shoots, showing an average of figures between 1.3 and 18.8. Four studies reported the hinge fracture frequency, indicating a range from 0 to 24% [ 10 , 29 , 32 , 34 ].…”

“…Seven studies [ 8 , 20 , 21 , 28 , 29 , 32 , 35 ] reported the mean intraoperative fluoroscopy shoots, showing an average of figures between 1.3 and 18.8. Four studies reported the hinge fracture frequency, indicating a range from 0 to 24% [ 10 , 29 , 32 , 34 ].…”