Bone-to-Bone and Implant-to-Bone Impingement: A Novel Graphical Representation for Hip Replacement Planning

Abstract

Bone-to-bone impingement (BTBI) and implantto-bone impingement (ITBI) risk assessment is generally performed intra-operatively by surgeons, which is entirely subjective and qualitative, and therefore, lead to sub-optimal results and recurrent dislocation in some cases. Therefore, a method was developed for identifying subject-specific BTBI and ITBI, and subsequently, visualising the impingement area on native bone anatomy to highlight where prominent bone should be resected. Activity definitions and subjectspecific bone geometries, with planned implants were used as inputs for the method. The ITBI and BTBI boundary and area were automatically identified using ray intersection and region growing algorithm respectively to retain the same 'conical clearance angle' obtained to avoid prosthetic impingement (PI). The ITBI and BTBI area was then presented with different colours to highlight the risk of impingement, and importance of resection. A clinical study with five patients after 2 years of THA was performed to validate the method. The results supported the study hypothesis, in that the predicted highest risk area (red coloured zone) was completely/majorly resected during the surgery. Therefore, this method could potentially be used to examine the effect of different pre-operative plans and hip motions on BTBI, ITBI, and PI, and to guide bony resection during THA surgery.

An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

“…Therefore, restriction of flexion is not only caused by implant-to-implant geometry but mostly by the alignment of the implant components in femoral and pelvic bone [33]. The ROM for bone-to-bone impingement, which is known as a major cause of limited ROM of the hip joint, was lower compared to implant-to-implant impingement, which is in line with the literature [23,32,71]. However, it should be carefully noted that the virtual ROMs during external rotation exceeded the clinical expectations [35,55,57], most likely due to the neglected active and passive parts of the soft-tissue structures, which are known to limit the ROM.…”

“…Generally, the motion was started at the initial configuration for each load case and continued until impingement [23,63] was detected. In our approach, impingement between femoral configuration-consisting of the femoral bone, stem, and prosthetic head-and pelvic configuration-consisting of the pelvic bone, acetabular cup, and liner-was recognized.…”

“…Currently, the occurrence of impingement is manually assessed by an orthopedic surgeon, by intraoperatively imposing specific motion patterns while the impingement is detected [23]. To analyze the maximum ROM of different implant designs, several experimental [24][25][26][27][28][29] and computational studies [13,18,20,21,23,[30][31][32][33][34][35][36][37][38], using computer-aided design (CAD), finite element analyses, or multibody simulations, have been conducted. Previous studies described the effect of the orientation of the acetabular cup, prosthetic head size on the impingement, and risk of dislocation [21,39,40].…”

“…Despite these studies, there is, to our knowledge, no approach that can be used to assess ROM in preoperative planning without subjecting the patient to additional radiation by CT scanning. In this regard, due to the high anatomical variability of hip joint geometry, patient-specific geometries are needed to perform more realistic computational preoperative analysis [23,32].…”

A Sensor-Based Screening Tool for Identifying High Pelvic Mobility in Patients Due to Undergo Total Hip Arthroplasty

“…This is in contrast to the current use of radiographs, which can only capture a snapshot in time of pelvic mobility; they are not practical to measure the full extent of variability in pelvic movements. These dynamic measures will also be an important contribution to model-based planning of acetabular cup positioning, based on the bone physiology of patients (captured using a computed tomography (CT) scan) and used to identify potential post-operative prosthetic impingement [33][34][35] or bony impingement [36,37]. Using the device with a dynamic tilt measurement algorithm, the pelvic tilt mapping for activities of daily living can be used to validate and further develop the impingement identification models by measuring the actual effect of pelvic tilt on post-operative impingement.…”