Preoperative Templating Research Articles

Morphological consistency of bilateral hip joints in adults based on the X-ray and CT data

PurposeThe application of the anatomical parameters of the contralateral hip joint to guide the preoperative template of the affected side relies on the bilateral hip symmetry. We investigated the bilateral hip symmetry and range of anatomical variations by measurement and comparison of bilateral hip anatomical parameters.MethodsThis study included 224 patients (448 hips) who were diagnosed with osteoarthritis (OA) and avascular necrosis (AVN) of the femur head, and underwent bilateral primary total hip arthroplasty (THA) in our hospital from January 2012 to August 2020. Imaging data included 224 patients X-ray and 30 CT data at the end of the cohort. Anatomical parameters, including the acetabular abduction angle and trochanteric height, were measured using the Noble method. Postoperative measurements included stem size, difference of leg length and offset.ResultsExcept for the isthmus width, there were no significant differences in the anatomical morphology of the hip joint. Among the demographic factors, there was a correlation between body weight and NSA. Among various anatomical parameters, a correlation was present between medullary cavity widths of T + 20, T, and T − 20. The difference in the use of stem size is not due to the morphological difference of bilateral medullary cavity, but due to the different of 1- or 2-stage surgery.ConclusionBilateral symmetry was present among the patients with normal morphology of the hip medullary cavity, theoretically confirming the feasibility of structural reconstruction of the hip joint using the hip joint on the uninjured side. Additionally, the difference in the morphology of the hip medullary cavity is not present in a single plane but is synergistically affected by multiple adjacent planes.

The Lesser Tuberosity Osteotomy Exposure for Total Shoulder Arthroplasty.

The lesser tuberosity osteotomy (LTO) is a commonly employed technique for mobilizing the subscapularis tendon during anatomic total shoulder arthroplasty that is performed through a deltopectoral approach. During this procedure, the lesser tuberosity is osteotomized from the proximal aspect of the humerus while maintaining the strong tendon-to-bone attachment of the subscapularis tendon insertion. After the shoulder arthroplasty is performed, the lesser tuberosity osseous fragment is then resecured to the proximal aspect of the humerus with heavy nonabsorbable suture, which allows for direct bone-to-bone compression and healing of the fragment to the proximal aspect of the humerus. This technique may be utilized for subscapularis tendon mobilization in any primary and some revision anatomic total shoulder arthroplasty procedures. The procedure is performed as follows. (1) Preoperative planning is performed. (2) The patient is positioned in the semi-upright beach-chair position, and the shoulder girdle and the upper arm are prepared and draped. (3) A standard deltopectoral approach is utilized. (4) A tenotomy of the long head of the biceps tendon is performed, exposing the bicipital groove. (5) An LTO is made from lateral to medial with an oscillating saw and is completed with use of an osteotome. (6) The remaining inferior portion of the subscapularis and capsule are released off of the humerus. (7) The total shoulder arthroplasty is completed up to the point of implantation of the final humeral component. (8) Four drill-holes are made lateral to the bicipital groove and osteotomy site. (9) Heavy nonabsorbable sutures, with or without cerclage wires, are passed from lateral to medial around the humeral stem and passed medial to the osteotomy fragment through the insertion of the subscapularis tendon. (10) The sutures are then tensioned and tied with the arm in 30° of external rotation. (11) The wound is irrigated, dried, and closed in layered fashion. The most commonly accepted alternative approaches include the subscapularis tenotomy and subscapularis peel techniques. The LTO approach technique was developed to take advantage of bone-to-bone healing and to address concerns regarding poor tendon-to-tendon or tendon-to-bone healing in the subscapularis tenotomy and subscapularis peel exposure techniques, respectively. Based on numerous published studies, excellent clinical results are achieved with anatomic total shoulder arthroplasty. When comparing surgical techniques involving the subscapularis in Level-I, randomized controlled trials, no significant differences exist among clinical outcomes, range of motion, or strength between the different techniques. Three-dimensional preoperative templating software allows for the anticipation of potential operative challenges, the prediction of implant limitations, and more accurate assessment of abnormal glenoid morphology and wear patterns.An articulating arm positioner can be helpful in controlling the arm position without the need for an extra surgical assistant.The goal thickness of the LTO is 10 mm. If the osteotomy is made too thin, there is a risk that the repair sutures cut through the lesser tuberosity fragment, leading to subscapularis repair failure.Releasing the capsule from the subscapularis is a critical step to ensure adequate tendon excursion for later repair and restoration of external rotation in arthritic shoulders. However, careful attention must be directed to the position and orientation of the axillary nerve in order to avoid iatrogenic injury during this critical step.Creating the drill-holes lateral to the bicipital groove takes advantage of the very strong and dense bone in that area of the proximal aspect of the humerus, enhancing the integrity of the repair.The tension band suture is critical to aid in further compression of the LTO fragment when the arm is brought into external rotation.Closing the rotator interval substantially increases the strength of the subscapularis repair; however, the closure of the interval must be made with the arm in at least 30° of external rotation in order to avoid iatrogenic motion restriction.Using interrupted nonabsorbable sutures to close the deltopectoral interval at the conclusion of the procedure is helpful in the event that any revision procedure is needed because these sutures will guide the revision surgeon toward making the deltopectoral approach in the correct interval. LTO = lesser tuberosity osteotomyROM = range of motionASES = American Shoulder and Elbow SurgeonsWOOS = Western Ontario Osteoarthritis of the Shoulder indexVAS = visual analog scaleSF-36 = 36-Item Short Form Health SurveySST = Simple Shoulder TestDVT = deep-vein thrombosis.

Templating for Total Hip Arthroplasty in the Modern Age.

Preoperative templating provides several benefits to the patient, surgeon, and hospital. Appropriate implant selection and sizing optimizes surgical workflow and leads to efficient care-delivery systems. Accurate templating establishes intraoperative targets for component position and reduces complications such as leg length inequality, impingement, wear, dislocation, and fracture, all of which lead to decreased patient satisfaction. Recent technological advances in preoperative imaging include a better understanding of patient-specific pelvic motion allowing the surgeon to preoperatively address the risk of lumbar pathology with adjustments in component placement and bearing choice. The introduction of two-dimensional to three-dimensional (3D) radiographs, biplanar low-dose radiographs, and computed tomography scans with 3D reconstructions have all allowed for a more comprehensive preoperative planning in 3D. This article will review the fundamentals of templating before total hip arthroplasty with an emphasis on how to incorporate and implement patient-specific pelvic motion and 3D templating into practice.

Use of Acetate Templates Over Digital Radiographs for Templating in Total Hip Arthroplasty: Technique and Its Validation.

Acetate templates were commonly used for templating for total hip arthroplasty. With digital radiographs having replaced conventional analogue radiographs, newer techniques are required. We describe a method for templating images of digital radiographs using conventional acetate templates, which is independent of a magnification marker or PACS system. Fifty-one patients (64 hips) who were treated with primary THA were prospectively evaluated. Templating was done by keeping the acetate template directly over the digital image of the radiograph on a liquid crystal display (LCD) monitor, after calibrating the linear scale generated by the digital radiography machine. The size of prosthesis predicted on this templating technique was compared with the actual sizes used during the surgery. Inter-observer and intra-observer reliabilities were assessed. Our calibration method was further validated by comparing the size of the cup calculated on postoperative radiograph using digital templating software (mediCAD Hectec GmbH) and the actual size used during surgery. Accurate size was predicted for 36.7% of the acetabular cup and 35.9% of femoral stems. The accuracy within ± one size was 89.9% for acetabular cups and 91.4% for femoral stems. Excellent inter-observer and intra-observer reliability were seen for both femoral and acetabular components. The method described provides an accurate, reproducible, convenient and low-cost technique of preoperative templating. It combines the ease of using acetate templates with the convenience of being able to use digital images, without the need for expensive software.

Intraoperative navigation and preoperative templating software are associated with increased glenoid baseplate screw length and use of augmented baseplates in reverse total shoulder arthroplasty.

BackgroundPreoperative templating software and intraoperative navigation have the potential to impact baseplate augmentation utilization and increase screw length for baseplate fixation in reverse total shoulder arthroplasty (rTSA). We aimed to assess their impact on the (1) baseplate screw length, (2) number of screws used, and (3) frequency of augmented baseplate use in navigated rTSA.MethodsWe compared 51 patients who underwent navigated rTSA with 63 controls who underwent conventional rTSA at a single institution. Primary outcomes included the screw length, composite screw length, number of screws used, percentage of patients in whom 2 screws in total were used, and use of augmented baseplates.ResultsNavigation resulted in the use of significantly longer individual screws (36.7 mm vs. 30 mm, P < .0001), greater composite screw length (84 mm vs. 76 mm, P = .048), and fewer screws (2.5 ± 0.7 vs. 2.8 ± 1, P = .047), as well as an increased frequency of using 2 screws in total (35 of 51 patients [68.6%] vs. 32 of 63 controls [50.8%], P = .047). Preoperative templating resulted in more frequent augmented baseplate utilization (76.5% vs. 19.1%, P < .0001).ConclusionThe difference in the screw length, number of screws used, and augmented baseplate use demonstrates the evolving role that computer navigation and preoperative templating play in surgical planning and the intraoperative technique for rTSA.

Trans-osseous intraoperative limb length measurement in hip replacement surgery

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Discrepancy of the limb length following total hip replacement is one of common complication. To reduce the occurrence, various modalities are used like pre-operative templating, navigation assisted measurements and intraoperative methods. This study was done using trans-osseous method of measurement using hip gauge which provides a faster, simpler assessment of limb length.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;M&lt;/strong&gt;&lt;strong&gt;ethods: &lt;/strong&gt;A prospective study of 25 patients who underwent uncemented hip arthroplasty was taken in the study and the LLD was measured before and after the surgical procedure. Patient were re-assessed for limb length discrepancy after 6 months with functional Harris hip score and radiological analysis on weight bearing standard X-ray antero-posterior view of the pelvis with bilateral hip joint.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;R&lt;/strong&gt;&lt;strong&gt;esults: &lt;/strong&gt;The results showed significant improvement in limb length discrepancy, and analysis of postoperative radiographs found the mean length difference of 2.44 mm and average Harris hip score was 95.5. No device related complications were reported, and none of them complained of the discomfort related to limb-length discrepancy after surgery. &lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;C&lt;/strong&gt;&lt;strong&gt;onclusions: &lt;/strong&gt;Trans-osseous fixed method using hip gauge provides a faster, reproducible and simpler method for the assessment of Limb length and aids with offset placement, acetabular anteversion for precise cup placement. This is a reliable method as it can be used both in the primary and revision hip surgery and most importantly doesn’t require any additional intraoperative imaging.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;

Should we employ preoperative templating in hip hemiarthroplasty after femoral neck fracture? A nested case-control study.

Dislocation following hip hemiarthroplasty is a serious complication. It remains unclear if acetabular morphology is associated with a higher risk of dislocation. The aim of our study was to investigate whether there are differences in hip morphology radiological parameters between patients who have suffered a dislocation episode, and those who have not suffered a dislocation. Between January 2015 and December 2018, a nested case-control study was performed. From 707 patients who underwent hip hemiarthroplasty because of femoral neck fracture, 50 patients (50 hips) suffered an episode of dislocation. They were randomly matched with 94 patients (100 hips) without dislocation (ratio 1:2). Clinical data regarding demographics, medical comorbidities and surgical and radiological parameters were studied. Statistically significantly smaller lateral centre-edge angle (LCEA) and femoral offset (FO) and greater Tönnis angle were found in the dislocation group. No differences in acetabular angle were seen. Neurological impairment prevalence was statistically significantly higher in patients who suffered a dislocation (60% vs. 44%, p = 0.011). The current study suggests that a smaller LCEA and FO, a greater TA, and neurological impairment could be related to a higher risk of hip hemiarthroplasty dislocation after femoral neck fracture in the elderly. We consider that preoperative templating could be helpful in identifying abnormal parameters and carefully planning surgery could lead to changes in treatment strategy, such as choosing a dual-mobility total hip arthroplasty.

Accuracy of Preoperative Templating in Total Hip Arthroplasty With Special Focus on Stem Morphology: A Randomized Comparison Between Common Digital and Three-Dimensional Planning Using Biplanar Radiographs

BackgroundAccurate preoperative planning is a key component of successful total hip arthroplasty (THA). The purpose of the present study was to compare the accuracy and reliability of three-dimensional (hipEOS) and common digital two-dimensional (TraumaCad) templating with special focus on stem morphology. Methods51 patients undergoing THA were randomized to two groups. Preoperative planning was performed on 23 patients with hipEOS (3D) and on 28 patients with TraumaCad (2D) planning software. Planning results were compared with the implanted component size. Inter- and intraobserver reliability as well as planning accuracy of both planning methods with special focus on straight and short stem design were recorded. ResultsIntraobserver reliability of both planning methods was good for component planning (ICC2,1: 0.835-0.967). Interobserver ICC2,1 for stem and cup planning were higher for 3D templating (3D ICC2,1: 0.906-0.918 vs. 2D ICC2,1: 0.835-0.843). Total stem and cup size predictions were within 2 sizes for 3D and within 3 sizes for 2D planning. Comparing short stem planning accuracy of both planning methods, absolute difference between implanted and planned component size was significantly lower in 3D planning (P = .029). There was no significant difference in straight stem (P = .935) and cup (P = .954) planning accuracy. ConclusionOur findings suggest that 3D templating with hipEOS software has a good overall reliability and may have a better planning accuracy of short stem prostheses than digital templating with TraumaCad software. Assuming that the number of implanted short stem prostheses will further increase in coming years, a more precise planning with 3D technique can contribute to improve surgery outcome.

Preoperative Planning for the Foot and Ankle: A Technique Tip

Category:Other; Ankle; Midfoot/ForefootIntroduction/Purpose:Computed tomography (CT) advanced imaging techniques are a valuable tool for orthopedic surgeons when evaluating complex foot and ankle pathology. With advances in CT data processing, surgeons can create custom reformation of the imaging data in real time using postprocessing imaging tools. This article presents a technique describing how to manipulate CT data using two of these tools, multiplanar reformation (MPR) and maximal intensity projection (MIP), to better visualize pathology and allow a more definitive diagnosis preoperatively. Despite their availability on most modern picture archiving and communication systems, most surgeons across orthopaedics disciplines fail to utilize these powerful tools.Methods:Patients with complex midfoot deformities underwent CT scans for diagnosis and preoperative planning. Case 1 underwent percutaneous pinning of multiple metatarsal fractures. Post-operatively she had severe pain localized to the second and third metatarsals. A CT scan obtained in standard axes failed to interpret the multiplanar deformities when viewed initially on PACS. Using MPR/MIP, the axes were rotated to generate a detailed view of the deformities and subsequently template osteotomies. Case two underwent arthrodesis of the second and third tarsometatarsal (TMT) joints for an unstable Lisfranc injury. Post-operatively she presented with severe midfoot pain prohibiting her return to athletics. Radiographs demonstrated normal alignment with hardware obscuring the joints. Standard CT axes were difficult to interpret due to metal artifact and oblique planes of the TMT joints. MPR/MIP reformatting allowed metal artifact reduction through axes adjustment, improving visualization and facilitating diagnosis of nonunion of the second and third TMT fusions.Results:Case One:MIP/MPR allowed manipulation of the CT scan in the axial and coronal planes provided a sagittal reformat of the entire second and third metatarsals. The second metatarsal had a gradual plantarflexion malunion of the diaphysis. The third metatarsal had an acute plantarflexed deformity of the metatarsal neck. Reformatting provided an accurate preoperative template for planned dorsiflexion osteotomies. Case Two: Metal artifact and the oblique orientation of the TMT joints prevented evaluation of previous fusions. MIP/MPR reformatting provided axes which were perpendicular to the TMT joints decreased metal artifact and demonstrated nonunion of the previous fusions. Use of MIP/MPR in this case provided valuable diagnostic information regarding the source of pain and a plan for removal of hardware and revision TMT fusions.Conclusion:The MPR/MIP function is available in most PACS systems and allows customizable CT reformats. The technique is easy to learn and can be done quickly in the office or pre-operative setting. The technology has facilitated streamlined pre- operative planning and improvements in injury visualization numerous times, particularly in complex deformities and trauma. Using MIP/MPR reformats, the authors have been able to identify critical fracture lines and relationships between anatomic structures which may otherwise have been missed or less precisely understood. The authors hope that this article will enhance awareness and encourage others to utilize this powerful technology.

Conventional computed tomography software can be used for accurate pre-operative templating in bipolar hip arthroplasty: A preliminary report

BackgroundThe aim of this study was to investigate the use of pre-operative templating for bipolar hip arthroplasty (BHA) for displaced femoral neck fracture using multiplanar reconstruction (MPR) of computed tomography (CT) images. MethodsNineteen patients who underwent BHA were enrolled in this study. For pre- and post-operative evaluation, a CT scan was performed from the pelvis to the knee joints. MPR of the CT image was done using software to measure the femoral head cup diameter, offset, stem size, length of the modular neck, distance from the neck osteotomy, and femoral anteversion. We compared these parameters pre- and post-operatively. ResultsBoth the femoral head cup diameter and length of the modular neck were found to be significantly different between pre- and post-operative measurements, although the differences were minor. Other parameters, including the femoral offset, were not significantly different between the pre- and post-operative measurements. The size of the femoral stem, cup diameter, and length of the modular neck were consistent with the planned size and accurate (within ±1 size) in more than 84% cases. ConclusionOur pre-operative templating approach for BHA using MPR of CT has potential clinical utility as a complementary tool for pre-operative planning using three-dimensional templating software. Moreover, this technique could be feasible in most hospitals without additional expenditure.

Effects of surgeon experience and patient characteristics on accuracy of digital pre-operative planning in total hip arthroplasty.

The effect of surgeon experience on accuracy of digital pre-operative planning for total hip arthroplasty (THA) remains unclear. The aims of our study were to compare pre-operative planning accuracy between fellow-trained orthopaedic surgeons and residents and to explore whether surgery indication effects the prediction accuracy. We prospectively reviewed 101 patients who underwent pre-operative digital templating for THA in our center from January 2019 to January 2020 with King Mark device. Extracted data included baseline characteristics and indication for primary arthroplasty. Pre-operative digital templating was performed separately by both a fellow-trained surgeon and a resident. Accuracy of each group was compared with the implanted components. The overall adequate pre-operative planning of the acetabular cup (exact or +/-1 size match) by the fellow-trained group was higher compared with the resident's group (77.2 and 64.3% respectively, p = 0.037), whereas the overall adequate pre-operative planning of the femoral stem (exact or +/-1 size match) was higher in the resident's group compared with the fellow-trained group (83.2 and 61.4% respectively, p < =0.001). The fellow-trained group showed better pre-operative planning of complex cases (developmental dysplasia of the hip and avascular necrosis of femoral head) than the resident's group. The experience of the planner does not significantly affect the accuracy of correctly predicting component sizes. However, in complex cases, fellow-trained surgeons should assist residents in digital pre-operative templating for THA.

A new and improved acetabular cup digital templating method and its clinical application.

Preoperative acetabular cup templating has an important auxiliary effect on hip surgery. The traditional acetabular cup templating method requires the measuring person to have some experience in total hip replacement (THA) surgery since the measurement results vary from person to person with differences between different measuring persons. To obtain stable templating results, we designed a new acetabular cup templating method and tested the inter-person measuring differences and measurement accuracy of this method. Meanwhile, the clinical application of this method was preliminarily explored. The pattern of this new method was manual labeling of imaging characteristic points and then programmed automatic measurements. The measurement process was performed entirely by orthopedic graduate students without any experience in hip replacement surgery. The inter-person measuring difference was evaluated by comparing the templating results of three measuring persons. The accuracy of the templating was evaluated by comparing the templating results with the actual size of the prosthesis in the surgery. The correlation between the position of the acetabular cup and the templating error was analyzed to explore the clinical significance of the templating results. This study was a retrospective study which included templating in a total of 406 cases for total hip replacement with cementless cup prosthesis. Digital measurements were performed using the Matlab software from MathWorks. The statistical comparison was performed using Kendall's W test. The results of the three measuring persons were completely identical in 61.8% (251/406) of cases, and the variation in 38.2% (155/406) of cases did not exceed one size of the acetabular cup. The Kendall's W coefficient was 0.977, and p < 0.01. The measurement accuracy is not as good as the traditional method in exactly accurate measurement and ±1 cup size, but it is similar to the traditional method in the ±2 cup sizes. The correlation between the templating error and the position evaluation of the implanted acetabular cups reveals: (1) larger the templating error, larger the proportion of the acetabular cups with poor position; (2) the proportion of acetabular cup with poor position slowly increased when the templating error was from 0 to 1 size, and the proportion rapidly increased when the templating error was from 1 to 2 size. All the patients with clear teardrop bottom and lateral superior edge of acetabulum were able to use our method to predict the size of the acetabular cup. The method has the following advantages: (1) it does not require the measuring person to have any previous experience of the THA surgery, which reduces the labor cost of the templating; (2) the differences between the measuring persons is small, the measurement result can be repeated; (3) it can predict the probability of acetabular cup with poor positioning according to the templating error, and thereby reminding the surgeon to recheck and correct the position of the acetabular cup in time during the surgery.

Classifications in Brief: The Dorr Classification of Femoral Bone.

Classifications in Brief: The Dorr Classification of Femoral Bone.

Alternative Management Of Bone Defect In Primary Total Knee Replacement

Introduction:Bone defects are not common in primary total knee arthroplasty (TKA) contrary to a revision setting. The surgeon must assess the degree of complexity preoperatively and intraoperatively and have a broad armamentarium available during surgery. Multiple surgical options are available to repair or reconstruct the loss of bone, these include: bone cement, bone grafts, metal augments and custom-made implants. Principles to consider in bone loss management are knee and patient-related. Bone defects in primary TKA are usually associated malalignment of the limb combined with severe destruction of the articular cartilage. The treatment options for bone defects in primary TKA should be focus on preserving of the host bone, joint line restoration, balancing the flexion /extension stability and stabilizing the prosthesis.Materials/Methods:We are presenting a 65 years old lady with severe osteoarthritis bilateral varus deformity with severe bone loss over the posterior tibia condyle. Pre operatively multiple radiographs AP, lateral, patella skyline and oblique view are taken. For this patien we taken CT scan for assessment of the bone defect particularly on the tabia side. The pre operative templating of the radiographs is fundamental important in this patient in planning for primary complex TKA . This patient underwent bilateral total knee replacement with semiconstraint implant with mesh and impaction bone grafting over the posterior apesct of proximal tibia.Result:This patient was susseccfully operated with no immediate and post operative complication. Patient which unable to walk because of severe deformity able to gain confidence level to walk and back to her daily living activityDiscussion:Primary and revision TKA will continue to increase, proper management of femoral and tibia bone loss represents a common situation that have to be faced by the orthopaedic surgeon. Whatever technique is used in management of bone loss during knee arthroplasty, certain fundamentals must be applied and the remaining bone structure will guide treatment. For this case the bone defect was severe uncontained less than 50% of the posterior proximal was lost. Impaction grafting with mesh was performed to create back the proximal tibia. It’s give a new solid platform for the tibia tray to be inserted and this may allow the patient to weight bear immediately post operatively. This will avoid from using fully constrain implant which put more stress on the joint. Periarticular defect requiring more than a minimal prosthetic augment, it is imperative to use stemmed components to transfer stress away from join. Reestablishment of well-aligned and stable implants is necessary, but this can’t be accomplished without a sufficient restoration of an eventual bone lossConclusion:There are several treatment options to deal with a specific bone defect in the primary TKA and these options will be dictated by the patient’s factors, the defect factors and surgeon experience. Careful preoperative planning is essential to ensure successful reconstruction with all the appropriate armamentarium prepared.

How should we evaluate robotics in the operating theatre?

The application of robotics in the operating theatre for knee arthroplasty remains controversial. As with all new technology, the introduction of new systems might be associated with a learning curve. However, guidelines on how to assess the introduction of robotics in the operating theatre are lacking. This systematic review aims to evaluate the current evidence on the learning curve of robot-assisted knee arthroplasty. An extensive literature search of PubMed, Medline, Embase, Web of Science, and Cochrane Library was conducted. Randomized controlled trials, comparative studies, and cohort studies were included. Outcomes assessed included: time required for surgery, stress levels of the surgical team, complications in regard to surgical experience level or time needed for surgery, size prediction of preoperative templating, and alignment according to the number of knee arthroplasties performed. A total of 11 studies met the inclusion criteria. Most were of medium to low quality. The operating time of robot-assisted total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is associated with a learning curve of between six to 20 cases and six to 36 cases respectively. Surgical team stress levels show a learning curve of seven cases in TKA and six cases for UKA. Experience with the robotic systems did not influence implant positioning, preoperative planning, and postoperative complications. Robot-assisted TKA and UKA is associated with a learning curve regarding operating time and surgical team stress levels. Future evaluation of robotics in the operating theatre should include detailed measurement of the various aspects of the total operating time, including total robotic time and time needed for preoperative planning. The prior experience of the surgical team should also be evaluated and reported. Cite this article: Bone Joint J 2020;102-B(4):407-413.

3D Printed Patient-Specific Acetabular Jig for Cup Placement in Total Hip Arthroplasty.

IntroductionAcetabular cup placement is an important modifiable factor determining complication rates like aseptic loosening and hip dislocation related to faulty cup placement, which by standard method is largely dependent upon eyeballing and surgeon’s judgment. We evaluated a self-designed, low-cost, patient-specific acetabular jig to guide cup placement in total hip arthroplasty in comparison to conventional technique.MethodsIt was a prospective randomized control study. Thirty-six patients were categorized into group-A & group-B. In group-A, virtually designed acetabular jig was 3 Dimensional (3D) printed and used intra-operatively to guide cup placement. In group-B, the standard method of cup placement was used. Acetabular cup placement was evaluated on post-operative x-rays and compared between two groups.ResultsIn group-A, angle of anteversion were significantly in centre of range of safe zone as compared to group B in which hip is maximally stable with more precision in creating hip centre as compared to group-B without any significant(p = 0.325) increase in surgical time or blood loss.ConclusionComputed tomography (CT) scan based virtual pre-operative templating and cup placement guided by virtually designed, patient-specific acetabular jig is a low-cost tool with a short learning curve which can be designed and made available easily. It is a useful tool in decreasing chances of malpositioning of cup and recreates hip centre close to anatomical one especially in cases where anatomy has been distorted such as bony ankylosis and developmental dysplasia of hip.

Can Body Height Be Used to Predict Knee Implant Sizes?

Introduction: Accuracy of pre-operative templating using radiographs or joint replacement programmes is variable. Implant modularity has increased the number of sizes available and trays used per procedure. Multiple intra-operative implant size trials lead to longer surgery time and greater instrument maintenance costs. It was hypothesised that patient factors could predict the size of implant and tray required, thereby increasing efficiency and reducing operative time. This study aims to identify correlation between implant size and body height to improve efficiency and reduce costs. Method: This prospective cohort study includes patients who underwent primary total knee replacement using the DePuy ATTUNE® Primary Total Knee System between 1st January 2016 to 7th August 2017 performed by a single surgeon, at a single hospital. Post-operative x-rays were reviewed for appropriate implant sizing. The DePuy ATTUNE® Primary Total Knee System has five sets, split into sizes 1-2, 3-5, 6-8 and 9-10. Results: 188 patients (205 knees) were included, 66 male and 122 female. Male height was 174.6cm (152-194.3) with average implant size 8. Female height was 158.7cm (145-177.8) with average implant size 5. The Spearman rank correlation between body height, femoral and tibial size were 0.793 and 0.837 respectively. All men &lt;170cm and &gt;185cm used the 6-8 and 9-10 set respectively. All women &lt;150cm and &gt;170cm used the 3-5 and 6-8 set respectively. Conclusion: The positive correlation identified coincides with existing literature. Using extremes of height and gender, surgeons and theatre staff could predict the likely trial set required, improve theatre efficiency and reduce costs.

Pre-operative templating in THA. Part II: a CT-based strategy to correct architectural hip deformities.

Pre-operative templating for total hip arthroplasty (THA) remains inaccurate due to improper magnification and alignment. We aimed to describe an improved templating strategy using computed tomography (CT) to predict component sizes and offsets with greater accuracy. We analysed 184 CT images acquired for pre-operative templating of primary THA. We aimed to restore native (pre-arthritic) femoral offset and limb length, by raising the head center to the level of the templated cup center cranio-caudally, but maintaining the pathologic (pre-operative) head center medio-laterally (except in medialized hips). Acetabular offset (AO) and femoral offset (FO) were measured on pre-operative CT scans, during acetate templating, and on post-operative true antero-posterior radiographs. The post-operative offsets were within ± 5mm from templated estimates in 174 hips (91%) for AO, in 116 hips (61%) for FO, in 111 hips (58%) for GO, and in 134 hips (70%) for neck cut level. The post-operative hip architecture reproduced the templated hip architecture within ±5mm in 77 hips (40%). The agreement between planned and post-operative parameters was moderate for stem size (0.57), cup size (0.62), AO (0.50), but fair for FO (0.45). The AO decreased in most arthritic types, notably in lateralized hips (6.6mm), but remained unchanged in medialized hips. The FO increased in most arthritic types (1.8-3.1mm) but remained unchanged in medialized and lateralized hips. We described a strategy for pre-operative templating in THA. Despite the accuracy of CT, the authors found significant variations between planned and post-operative reconstructions, which suggest that pre-operative templating should only be used as an approximate guide.

Pre-operative planning in THA. Part III: do implant size prediction and offset restoration influence functional outcomes after THA?

Few studies evaluated clinical benefits of pre-operative templating in total hip arthroplasty (THA). We investigated whether mismatch between planned and real implant sizes and medio-lateral offsets compromises THA outcomes. We reviewed records of 184 primary THAs with pre-operative CT scans used for templating. Acetabular offset (AO), femoral offset (FO) and global offset (GO) were measured on pre-operative CT scans, during acetate templating, and post-operative antero-posterior radiographs. Multivariable analyses were performed to determine if Forgotten Joint Score (FJS) and Oxford Hip Score (OHS) at > 2years were associated with differences between post-operative and planned parameters. The FJS and OHS were not influenced by mismatch of component sizes nor of FO and GO. The FJS was better when the post-operative AO was greater than planned (p = 0.050). The FJS differed among arthritic types (p = 0.015). Multivariable analyses confirmed that older patients had better OHS (beta - 0.16; p = 0.033) and FJS (beta 0.74; p = 0.002), medialized hips had worse FJS (beta - 20.1; p = 0.041) and hips with greater AO than planned had better FJS (beta 1.71; p = 0.024) CONCLUSIONS: Implanting a component of different size than planned did not compromise THA outcomes, but medialized hips had worse scores, and conservative acetabular reaming improved scores.

Observed effect of femoral component undersizing and a collarless design in the development of radiolucent lines in cementless total hip arthroplasty.

BackgroundThe objective of this study was to determine the prevalence of radiolucent lines (RLLs) around the femoral component in a cohort of patients who underwent well-functioning cementless total hip arthroplasty (THA).MethodsA cohort of unrevised Corail (DePuy Synthes, Raynham, MA) femoral components (n = 636) were analyzed at a median follow-up of 6.0 years (interquartile range: 5.2-6.8) with the Oxford Hip Score (OHS) and radiographs. Two independent observers assessed the radiographs for the presence of RLLs.ResultsThe overall prevalence of RLLs in zone 7 was 13% (83/636). Patients with RLLs in zone 7 had an average OHS of 40.3 (15-48), and those who did not have RLLs in zone 7 had an average OHS of 38 (6-48), P = .07. Both groups had an average pain score of 1.6 out of 5, P = .5. The prevalence of RLLs in zone 7 was much less in the collared femoral components (2.6% prevalence) than in the collarless components (23.6% prevalence), but there was heterogeneity between these 2 groups preventing comparison. Logistic regression analysis of only the collarless components identified undersizing as the only predictive (odds ratio = 2.6) factor for RLL development in zone 7.ConclusionsUndersizing the Corail stem is strongly predictive of developing RLLs in zone 7. Preoperative templating for the appropriate size is critical. We observed more RLLs in zone 7 with the collarless design Corail, but a comparison study with the same bearing couple is needed to investigate this further.