The Accuracy of Patient-Specific Instrumentation with Laser Guidance in a Dynamic Total Hip Arthroplasty: A Radiological Evaluation

Abstract

The functional positioning of components in a total hip arthroplasty (THA) and its relationship with individual lumbopelvic kinematics and a patient’s anatomy are being extensively studied. Patient-specific kinematic planning could be a game-changer; however, it should be accurately delivered intraoperatively. The main purpose of this study was to verify the reliability and accuracy of a patient-specific instrumentation (PSI) and laser-guided technique to replicate preoperative dynamic planning. Thirty-six patients were prospectively enrolled and received dynamic hip preoperative planning based on three functional lateral spinopelvic X-rays and a low dose CT scan. Three-dimensional (3D) printed PSI guides and laser-guided instrumentation were used intraoperatively. The orientation of the components, osteotomy level and change in hip length and offset were measured on postoperative CT scans and compared with the planned preoperative values. The length of surgery was compared with that of a matched group of thirty-six patients who underwent a conventional THA. The mean absolute deviation from the planned inclination and anteversion was 3.9° and 4.4°, respectively. In 92% of cases, both the inclination and anteversion were within +/− 10° of the planned values. Regarding the osteotomy level, offset change and limb length change, the mean deviation was, respectively, 1.6 mm, 2.6 mm and 2 mm. No statistically significant difference was detected when comparing the planned values with the achieved values. The mean surgical time was 71.4 min in the PSI group and 60.4 min in the conventional THA group (p < 0.05). Patient-specific and laser-guided instrumentation is safe and accurately reproduces dynamic planning in terms of the orientation of the components, osteotomy level, leg length and offset. Moreover, the increase in surgical time is negligible.

Achieving Precise Cup Positioning in Direct Anterior Total Hip Arthroplasty: A Narrative Review

“…Guidance by patient-specific instrumentation may further increase accuracy [ 55 , 74 ]. A recent meta-analysis by Constantinescu et al reported favorable results for patient-specific instrumentation regarding the deviation from preoperative planning for anteversion, inclination and positioning within the Lewinnek safe zones compared to standard instrumentation [ 55 ].…”

“…A recent meta-analysis by Constantinescu et al reported favorable results for patient-specific instrumentation regarding the deviation from preoperative planning for anteversion, inclination and positioning within the Lewinnek safe zones compared to standard instrumentation [ 55 ]. Feretti et al reported that when using patient-specific instrumentation, 92% of the implants were within 10° deviation from the planned anteversion and inclination, while there was a slight increase in surgical time [ 74 ]. Disadvantages are limited choice in implant options, additional costs, and additional radiation exposure due to the planning CT.…”

Femoral Anteversion in Total Hip Arthroplasty: Retrospective Comparison of Short- and Straight-Stem Models Using CT Scans

“…In order to improve the accuracy regarding the as-physiological-as-possible placement of the stem in total hip arthroplasty (THA), the use of patient-specific instrumentation with laser guidance to reduce the risk of femoral anteversion should be considered. Ferretti et al [ 5 ] demonstrated that using a positioning system enables the accurate positioning of the stem and cup. When applied, operating times are not significantly prolonged and even improve in correlation with the user’s learning curve [ 5 ].…”

“…To achieve optimal results, the femoral stem fixation should satisfy several requirements, including ease of handling during surgery, preservation of bone stock and soft tissue, and stable long-term fixation [ 2 , 3 , 4 ]. Not only should the surface texture, geometric configuration, and choice of implant material be carefully considered, but the appropriate operative approach is also necessary in order to achieve the best possible results [ 5 ]. Furthermore, reconstructing the individual’s hip geometry is crucial in order to achieve optimal force distribution and range of motion while minimizing the risk of aseptic loosening, component wear, and dislocation [ 6 , 7 , 8 ].…”

Comparison of Three 3D Segmentation Software Tools for Hip Surgical Planning

“…Even osteoporosis is characterised by changes in bone biologic material and structural distraction with the consequent reduction in the resistance of bone tissue that predisposes to an increased risk of fractures [ 11 ]. In all these clinical situations, an anatomical 3D model results in being helpful in surgical planning [ 12 , 13 ] and communication with the patients [ 14 , 15 ]. Moreover, it has been demonstrated that the anatomical 3D model helps reduce surgery duration [ 16 , 17 ] and intra-operative blood loss, allowing better surgical outcomes [ 18 ].…”