Aims

Vascular compromise due to arterial injury is a rare but serious complication of a proximal humeral fracture. The aims of this study were to report its incidence in a large urban population, and to identify clinical and radiological factors which are associated with this complication. We also evaluated the results of the use of our protocol for the management of these injuries.

Aims

Robotic arm-assisted surgery offers accurate and reproducible guidance in component positioning and assessment of soft-tissue tensioning during knee arthroplasty, but the feasibility and early outcomes when using this technology for revision surgery remain unknown. The objective of this study was to compare the outcomes of robotic arm-assisted revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) versus primary robotic arm-assisted TKA at short-term follow-up.

Aims. Accurate diagnosis of chronic periprosthetic joint infection (PJI) presents a significant challenge for hip surgeons. Preoperative diagnosis is not always easy to establish, making the intraoperative decision-making process crucial in deciding between one- and two-stage revision total hip arthroplasty (THA). Calprotectin is a promising point-of-care novel biomarker that has displayed high accuracy in detecting PJI. We aimed to evaluate the utility of intraoperative calprotectin lateral flow immunoassay (LFI) in THA patients with suspected chronic PJI. Methods. The study included 48 THAs in 48 patients with a clinical suspicion of PJI, but who did not meet European Bone and Joint Infection Society (EBJIS) PJI criteria preoperatively, out of 105 patients undergoing revision THA at our institution for possible PJI between November 2020 and December 2022. Intraoperatively, synovial fluid calprotectin was measured with LFI. Cases with calprotectin levels ≥ 50 mg/l were considered infected and treated with two-stage revision THA; in negative cases, one-stage revision was performed. At least five tissue cultures were obtained; the implants removed were sent for sonication. Results. Calprotectin was positive (≥ 50 mg/l) in 27 cases; out of these, 25 had positive tissue cultures and/or sonication. Calprotectin was negative in 21 cases. There was one false negative case, which had positive tissue cultures. Calprotectin showed an area under the curve of 0.917, sensitivity of 96.2%, specificity of 90.9%, positive predictive value of 92.6%, negative predictive value of 95.2%, positive likelihood ratio of 10.6, and negative likelihood ratio of 0.04. Overall, 45/48 patients were correctly diagnosed and treated by our algorithm, which included intraoperative calprotectin measurement. This yielded a 93.8% concordance with postoperatively assessed EBJIS criteria. Conclusion. Calprotectin can be a valuable tool in facilitating the intraoperative decision-making process for cases in which chronic PJI is suspected and diagnosis cannot be established preoperatively. Cite this article: Bone Joint J 2024;106-B(5 Supple B):118–124

Aims

Femoral component anteversion is an important factor in the success of total hip arthroplasty (THA). This retrospective study aimed to investigate the accuracy of femoral component anteversion with the Mako THA system and software using the Exeter cemented femoral component, compared to the Accolade II cementless femoral component.

Aims

Research on hip biomechanics has analyzed femoroacetabular contact pressures and forces in distinct hip conditions, with different procedures, and used diverse loading and testing conditions. The aim of this scoping review was to identify and summarize the available evidence in the literature for hip contact pressures and force in cadaver and in vivo studies, and how joint loading, labral status, and femoral and acetabular morphology can affect these biomechanical parameters.

Aims

This study aimed to establish the optimal fixation methods for calcaneal tuberosity avulsion fractures with different fragment thicknesses in a porcine model.

The purposes of this study were to report the accuracy of stem anteversion for Exeter cemented stems with the Mako hip enhanced mode and to compare it to Accolade cementless stems. We reviewed the data of 25 hips in 20 patients who underwent THA through the posterior approach with Exeter stems and 25 hips in 19 patients with Accolade stems were matched for age, gender, height, weight, disease, and approaches. There was no difference in the target stem anteversion (20°–30°) between the groups. Two weeks after surgery, CT images were taken to measure stem anteversion. The difference in stem anteversion between the plan and the postoperative CT measurements was 1.2° ± 3.8° (SD) on average with cemented stems and 4.2° ± 4.2° with cementless stems, respectively (P <0.05). The difference in stem anteversion between the intraoperative measurements and the postoperative CT measurements was 0.75° ± 1.8° with Exeter stems and 2.2° ± 2.3° with Accolade stems, respectively (P <0.05). This study demonstrated a high precision of anteversion for Exeter cemented stems with the Mako enhanced mode and its clinical accuracy was better with the cemented stems than that with the cementless stems. Although intraoperative stem anteversion measurements with the Mako system were more accurate with the cemented stems than that with the cementless stem, the difference was about 1° and the accuracy of intra-operative anteversion measurements was quite high even with the cementless stems. The smaller difference in stem anteversion between the plan and postoperative measurements with the cemented stems suggested that stem anteversion control was easier with cemented stems under the Mako enhanced mode than that with cementless stems. Intraoperative stem anteversion measurement with Mako total hip enhanced mode was accurate and it was useful in controlling cemented stem anteversion to the target angle

Aims

Disorders of bone integrity carry a high global disease burden, frequently requiring intervention, but there is a paucity of methods capable of noninvasive real-time assessment. Here we show that miniaturized handheld near-infrared spectroscopy (NIRS) scans, operated via a smartphone, can assess structural human bone properties in under three seconds.

Aims

To examine the long-term outcome of arthrodesis of the hip undertaken in a paediatric population in treating painful arthritis of the hip. In our patient population, most of whom live rurally in hilly terrain and have limited healthcare access and resources, hip arthrodesis has been an important surgical option for the monoarticular painful hip in a child.

Aims

Navigation devices are designed to improve a surgeon’s accuracy in positioning the acetabular and femoral components in total hip arthroplasty (THA). The purpose of this study was to both evaluate the accuracy of an optical computer-assisted surgery (CAS) navigation system and determine whether preoperative spinopelvic mobility (categorized as hypermobile, normal, or stiff) increased the risk of acetabular component placement error.

Aims

Intraoperative pressure sensors allow surgeons to quantify soft-tissue balance during total knee arthroplasty (TKA). The aim of this study was to determine whether using sensors to achieve soft-tissue balance was more effective than manual balancing in improving outcomes in TKA.

The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA, the tibial cutting surface is decided parallel to the femoral cutting surface (or trial component) with in-line traction. These approaches are categorized as unrestricted KA because there is no consideration of leg alignment or component orientation. Restricted KA is an approach where the periarthritic joint surface is replicated within a safe range, due to concerns about extreme alignments that have been considered ‘alignment outliers’ in the neutral mechanical alignment approach. More recently, functional alignment and inverse kinematic alignment have been advocated, where bone cuts are made following intraoperative planning, using intraoperative measurements acquired with computer assistance to fulfill good coordination of soft-tissue balance and alignment. The KA-TKA approach aims to restore the patients’ own harmony of three knee elements (morphology, soft-tissue balance, and alignment) and eventually the patients’ own kinematics. The respective approaches start from different points corresponding to one of the elements, yet each aim for the same goal, although the existing implants and techniques have not yet perfectly fulfilled that goal

Aims

Hip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane.

Abstract. Objectives. High tibial osteotomy for knee realignment is effective at relieving symptoms of knee osteoarthritis but the operation is surgically challenging. A new personalised treatment with simpler surgery using pre-operatively planned measurements from computed tomography (CT) imaging and 3D-printed implants and instrumentation has been designed and is undergoing clinical trial. The aim of this study was to evaluate the early clinical results of a preliminary pilot study evaluating the safety of this new personalised treatment. Methods. The single-centre prospective clinical trial is ongoing (IRCCS Istituto Ortopedico Rizzoli; IRB-0013355; ClinicalTrials.gov NCT04574570), with recruitment completed and all patients having received the novel custom surgical treatment. To preserve the completeness of the trial reporting, only surgical aspects were evaluated in the present study. Specifically, the length of the implanted osteosynthesis screws was considered, being determined pre-operatively eliminating intraoperative measurements, and examined post-operatively (n=7) using CT image processing (ScanIP, Synopsys) and surface distance mapping. The surgical time, patient discharge date and ease of wound closure were recorded for all patients (n=25). Results. Over the study period the average surgical time (skin incision to suture) reduced from 54 to 31 minutes (range: 17–62, n=25). It was noted that wound closure was easier than the conventional surgery due to the lower profile of the implant. Over seventy percent of patients were discharged day 2 post-op. The position, orientation and length of all screws matched the pre-operative configuration to within approximately 1mm. Conclusions. The early trial results are promising from a clinical perspective. It was evident that surgical time was saved because no intraoperative screw length measurements were required, and the use of custom instrumentation significantly reduced the surgical inventory. The reduced invasiveness and ease of surgery may contribute to faster patient recovery compared to conventional techniques. The full trial results will be reported later this year. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Abstract. Objectives. There is renewed interest in bi-unicondylar arthroplasty (Bi-UKA) for patients with medial and lateral tibiofemoral osteoarthritis, but a spared patellofemoral compartment and functional cruciate ligaments. The bone island between the two tibial components may be at risk of tibial eminence avulsion fracture, compromising function. This finite element analysis compared intraoperative tibial strains for Bi-UKA to isolated medial unicompartmental arthroplasty (UKA-M) to assess the risk of avulsion. Methods. A validated model of a large, high bone-quality tibia was prepared for both UKA-M and Bi-UKA. Load totalling 450N was distributed between the two ACL bundles, implant components and collateral ligaments based on experimental and intraoperative measurements with the knee extended and appropriately sized bearings used. 95th percentile maximum principal elastic strain was predicted in the proximal tibia. The effect of overcuts/positioning for the medial implant were studied; the magnitude of these variations was double the standard deviation associated with conventional technique. Results. For all simulations, strains were an order of magnitude lower than that associated with bone fracture. Highest strain occurred in the spine, under the anteromedial ACL attachment, adjacent to transverse overcut of the medial component. Consequently, Bi-UKA had little effect on strain: <10% increases were predicted when compared to UKA-M with equivalent medial cuts/positioning. However, surgical overcutting/positional variation that resulted in loss of anteromedial bone in the spine increased strain. The biggest increase was for lateral translation of the medial component: 44% and 42% for UKA-M and Bi-UKA, respectively. Conclusions. For a large tibia with high bone quality, Bi-UKA with a well-positioned lateral implant had no tangible effect on the risk of tibial eminence avulsion fracture compared to UKA-M. Malpositioning of the medial component that removes bone from the anterior spine could prove problematic for smaller tibiae. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Aims

Hip arthroplasty does not always restore normal anatomy. This is due to inaccurate surgery or lack of stem sizes. We evaluated the aptitude of four total hip arthroplasty systems to restore an anatomical and medialized hip rotation centre.

INTRODUCTION. The restoration of physiological kinematics is one of the goals of a total knee arthroplasty (TKA). Navigation systems have been developed to allow an accurate and precise placement of the implants. But its application to the intraoperative measurement of knee kinematics has not been validated. The hypothesis of this study was that the measurement of the knee axis, femoral rotation, femoral translation with respect to the tibia, and medial and lateral femorotibial gaps during continuous passive knee flexion by the navigation system would be different from that by fluoroscopy taken as reference. MATERIAL – METHODS. Five pairs of knees of preserved specimens were used. The e.Motion FP ® TKA (B-Braun Aesculap, Tuttlingen, Germany) was implanted using the OrthoPilot TKA 4.3 version and Kobe version navigation system (B-Braun Aesculap, Tuttlingen, Germany). Kinematic recording by the navigation system was performed simultaneously with fluoroscopic recording during a continuous passive flexion-extension movement of the prosthetic knee. Kinematic parameters were extracted from the fluoroscopic recordings by image processing using JointTrack Auto ® software (University of Florida, Gainesville, USA). The main criteria were the axis of the knee measured by the angle between the center of the femoral head, the center of the knee and the center of the ankle (HKA), femoral rotation, femoral translation with respect to the tibia, and medial and lateral femorotibial gaps. The data analysis was performed by a Kappa correlation test. The agreement of the measurements was assessed using the intraclass correlation coefficient (ICC) and its 95% confidence interval. RESULTS. The respective CCIs were as follows: HKA angle 0.839 [0.820; 0.856]; femoral translation 0.560 [0.517; 0.600]; femoral rotation 0.652 [0.616; 0.686]; medial femorotibial gap 0.905 [0.894; 0.916]; lateral femorotibial gap 0.767 [0.740; 0.791]. DISCUSSION. Measurements of TKA kinematics by the navigation system and by fluoroscopy were consistent for HKA angle and medial and lateral femorotibial gaps, but not for femoral translation and femoral rotation. These differences can be explained by a methodological bias. At the end of this work, the specific navigation system cannot be considered as a reliable instrument for measuring the kinematics of a TKA

Robotic-assisted technology in total knee arthroplasty (TKA) aims to increase implantation accuracy, with real-time data being used to estimate intraoperative component alignment. Postoperatively, Perth computed tomography (CT) protocol is a valid measurement technique in determining both femoral and tibial component alignments. The aim of this study was to evaluate the accuracy of intraoperative component alignment by robotic-assisted TKA through CT validation. A total of 33 patients underwent TKA using the MAKO robotic-assisted TKA system. Intraoperative measurements of both femoral and tibial component placements, as well as limb alignment as determined by the MAKO software were recorded. Independent postoperative Perth CT protocol was obtained (n.29) and compared with intraoperative values. Mean absolute difference between intraoperative and postoperative measurements for the femoral component were 1.17 degrees (1.10) in the coronal plane, 1.79 degrees (1.12) in the sagittal plane, and 1.90 degrees (1.88) in the transverse plane. Mean absolute difference between intraoperative and postoperative measurements for the tibial component were 1.03 degrees (0.76) in the coronal plane and 1.78 degrees (1.20) in the sagittal plane. Mean absolute difference of limb alignment was 1.29 degrees (1.25), with 93.10% of measurements within 3 degrees of postoperative CT measurements. Overall, intraoperatively measured component alignment as estimated by the MAKO robotic-assisted TKA system is comparable to CT-based measurements

Introduction. Primary robotic-arm assisted total hip arthroplasty (THA) yields more accurate and reproducible acetabular cup placement, nonetheless, data is scarce in terms of outcomes. The purpose of the present study was to report on patient-reported outcomes (PROMs) in a large group of patients who underwent robotic-arm assisted THA. The authors hypothesized that (1) patients who underwent robotic-arm assisted primary THA would achieve favorable and significant improvement in PROMs, (2) an accurate and reproducible acetabular cup placement with respect to the defined SafeZones would be obtained, and (3) a low rate of THA dislocation would be observed. Methods. Prospectively collected data were retrospectively reviewed between April 2012 to May 2017. Primary THA using Mako Robotic-Arm [Mako Surgical Corp. (Stryker), Fort Lauderdale, FL, USA] with minimum two-year follow-up for the Harris Hip Score (HHS) and the Forgotten Joint Score-12 (FJS-12) were included. Exclusion criteria were: bodymass index (BMI) > 40 kg/m2, age < 21-year old, worker's compensation, or unwilling to participate. Visual analog scale (VAS) for pain and patient satisfaction were obtained. Intraoperative measurements for leg-length, global offset, acetabular inclination and version were documented. Results. 501 hips were included (57.29% females), follow-up was 43.99 ± 15.59 months. Average age was 58.70 ± 9.41 years, and the BMI was 28.41 ± 4.55 kg/m2. The group reported HHS of 90.87 ± 13.45, FJS-12 of 79.97 ± 25.87, VAS of 1.20 ± 2.06, and patient satisfaction of 8.85 ± 2.08. Intraoperative values for acetabular inclination and version were 40.0° ± 2.2 ° and 20.5° ± 2.4° respectively. Revision due to instability was 0.2%. Conclusions. Patients who received primary robotic-arm assisted THA reported excellent results at 44-month follow-up for multiple PROMs. Consistency in acetabular cup placement accuracy was achieved in regard to the Lewinnek and Callanan safe-zones