Aims

The objective of this study was to compare simulated range of motion (ROM) for reverse total shoulder arthroplasty (rTSA) with and without adjustment for scapulothoracic orientation in a global reference system. We hypothesized that values for simulated ROM in preoperative planning software with and without adjustment for scapulothoracic orientation would be significantly different.

Aims

Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies.

Aims

Despite limited clinical scientific backing, an additional trochanteric stabilizing plate (TSP) has been advocated when treating unstable trochanteric fractures with a sliding hip screw (SHS). We aimed to explore whether the TSP would result in less post operative fracture motion, compared to SHS alone.

Dual mobility hip arthroplasty utilizes a freely rotating polyethylene liner to protect against dislocation. As liner motion has not been confirmed in vivo, we investigated the liner kinematics in vivo using dynamic radiostereometry. 16 patients with Anatomical Dual Mobility acetabular components were included. Markers were implanted in the liners using a drill guide. Static RSA recordings and patient reported outcome measures were obtained at post-op and 1-year follow-up. Dynamic RSA recordings were obtained at 1-year follow-up during a passive hip movement: abduction/external rotation, adduction/internal rotation (modified FABER-FADIR), to end-range and at 45° hip flexion. Liner- and neck movements were described as anteversion, inclination and rotation. Liner movement during modified FABER-FADIR was detected in 12 of 16 patients. Median (range) absolute liner movements were: anteversion 10° (5–20), inclination 6° (2–12), and rotation 11° (5–48) relative to the cup. Median absolute changes in the resulting liner/neck angle (small articulation) was 28° (12–46) and liner/cup angle (larger articulation) was 6° (4–21). Static RSA showed changes in median (range) liner anteversion from 7° (-12–23) postoperatively to 10° (-3–16) at 1-year follow-up and inclination from 42 (35–66) postoperatively to 59 (46–80) at 1-year follow-up. Liner/neck contact was associated with high initial liner anteversion (p=0.01). The polyethylene liner moves over time. One year after surgery the liner can move with or without liner/neck contact. The majority of movement is in the smaller articulation between head and liner

Aims

The aim of this study was to assess and compare active rotation of the forearm in normal subjects after the application of a short-arm cast (SAC) in the semisupination position and a long-arm cast (LAC) in the neutral position. A clinical study was also conducted to compare the functional outcomes of using a SAC in the semisupination position with those of using a LAC in the neutral position in patients who underwent arthroscopic triangular fibrocartilage complex (TFCC) foveal repair.

The Step Holter is a software and mobile application that can be used to easily study gait analysis. The application can be downloaded for free on the App Store and Google Play Store for iOS and Android devices. The software can detect with an easy calibration the three planes to detect the movement of the gait. Before proceeding with the calibration, the smartphone can be placed and fixed with a band or stowed into a long sock with its top edge at the height of the joint line, in the medial side of the tibia. The calibration consists in bending the knee about 20 to 30 degrees and then making a rotation movement, leaving the heel fixed to the ground as a rotation fulcrum. After calibration, the program records data related to lateral flexion, rotation, and bending of the leg. This data can be viewed directly from the smartphone screen or transmitted via a web link to the Step Holter web page . www.stepholter.com. by scanning a personal QR code. The web page allows the users to monitor the test during its execution or view data for tests done previously. By pressing the play button, it is possible to see a simulation of the patient's leg and its movement. With the analyze button, the program is capable of calculating the swing and stance phase of every single step, providing a plot with time and percentages. Finally, with the Get Excel button, test data can be conveniently exported for more in-depth research. The advantage of this application is not only to reduce the costs of a machine for the study of gait analysis but also being able to perform tests quickly, without expensive hardware or software and be used in specific spaces, without specialized personnel. Furthermore, the application can collect important data concerning rotation that cannot be highlighted with the classic gait analysis. The versatility of a smartphone allows tests to be carried out not only during walking but also by climbing or descending stairs or sitting down or getting up from a chair. This software offers the possibility to easily study any kind of patients; Older patients, reluctant to leave their homes for a gait analysis can be tested at home or during an office control visit. Step Holter could be one small step for patients, one giant leap for gait study simplicity. For any figures or tables, please contact authors directly

Aims

The aim of this study was to conduct the largest low contact stress (LCS) retrieval study to elucidate the failure mechanisms of the Porocoat and Duofix femoral component. The latter design was voluntarily recalled by the manufacturer.

Aims

The introduction of a novel design of total knee arthroplasty (TKA) must achieve outcomes at least as good as existing designs. A novel design of TKA with a reducing radius of the femoral component and a modified cam-post articulation has been released and requires assessment of the fixation to bone. Radiostereometric analysis (RSA) of the components within the first two postoperative years has been shown to be predictive of medium- to long-term fixation. The aim of this study was to assess the stability of the tibial component of this system during this period of time using RSA.

Aims

Scapular notching is a frequently observed radiographic phenomenon in reverse shoulder arthroplasty (RSA), signifying impingement of components. The purposes of this study were to evaluate the effect of glenoid component size and glenosphere type on impingement-free range of movement (ROM) for extension and internal and external rotation in a virtual RSA model, and to determine the optimal configuration to reduce the incidence of friction-type scapular notching.

Objectives. The objective of this study was to quantify the relative movement between the articular surfaces in the tibiotalar and subtalar joints during normal walking in asymptomatic individuals. Methods. 3D movement data of the ankle joint complex were acquired from 18 subjects using a biplanar fluoroscopic system and 3D-to-2D registration of bone models obtained from CT images. Surface relative velocity vectors (SRVVs) of the articular surfaces of the tibiotalar and subtalar joints were calculated. The relative movement of the articulating surfaces was quantified as the mean relative speed (RS) and synchronization index (SI. ENT. ) of the SRVVs. Results. SI. ENT. and mean RS data showed that the tibiotalar joint exhibited translational movement throughout the stance, with a mean SI. ENT. of 0.54 (. sd. 0.21). The mean RS of the tibiotalar joint during the 0% to 20% post heel-strike phase was 36.0 mm/s (. sd. 14.2), which was higher than for the rest of the stance period. The subtalar joint had a mean SI. ENT. value of 0.43 (. sd. 0.21) during the stance phase and exhibited a greater degree of rotational movement than the tibiotalar joint. The mean relative speeds of the subtalar joint in early (0% to 10%) and late (80% to 90%) stance were 23.9 mm/s (. sd. 11.3) and 25.1 mm/s (. sd 9.5). , respectively, which were significantly higher than the mean RS during mid-stance (10% to 80%). Conclusion. The tibiotalar and subtalar joints exhibited significant translational and rotational movement in the initial stance, whereas only the subtalar joint exhibited significant rotational movement during the late stance. The relative movement on the articular surfaces provided deeper insight into the interactions between articular surfaces, which are unobtainable using the joint coordinate system. Cite this article: C-B. Phan, D-P. Nguyen, K. M. Lee, S. Koo. Relative movement on the articular surfaces of the tibiotalar and subtalar joints during walking. Bone Joint Res 2018;7:501–507. DOI: 10.1302/2046-3758.78.BJR-2018-0014.R1

Objectives

To validate the precision of digitally reconstructed radiograph (DRR) radiostereometric analysis (RSA) and the model-based method (MBM) RSA with respect to benchmark marker-based (MM) RSA for evaluation of kinematics in the native hip joint.

Introduction. Femoroacetabular impingement (FAI) is a morphological hip joint deformity associated with pain and early degenerative changes. Cam-type FAI is prevalent in young male athletes. While biomechanical deficiencies (decreased hip muscle strength and range of motion (ROM)) have been associated with symptomatic cam-type FAI (sFAI), results have been conflicting and little is known about biomechanical characteristics during dynamic tasks. Objectives. (1) Compare coronal-plane hip muscle strength, activation and joint rotation during movement tasks in sFAI hips against healthy controls. (2) Investigate the effect of hip internal rotation ROM (IR-ROM) on these outcomes. Methods. 11 sFAI and 24 well-matched healthy control hips from 18 young adult male athletes were recruited (Table.1). Passive hip IR-ROM was measured with goniometry. Weight-normalised hip abductor and adductor isometric maximal voluntary contraction torques were quantified with handheld dynamometry. Gluteus medius and adductor longus activation and hip coronal-plane kinematics were collected with surface electromyography (EMG) and motion-capture during time-defined phases of sit-to-stand (Fig.1) and single-leg-squat (Fig.2) tasks. Effect of sFAI with hip IR-ROM as a separate independent variable was calculated with 1-way MANCOVA. Results. sFAI had significantly less IR-ROM (19.25°±5.94) than controls (28.83°±7.24) (p<0.001). During the sit-to-stand ascent phase, significantly more hip abduction (F=4.93, p=0.03) was observed in sFAI (13.06°±3.16) compared to controls (10.16°±3.72). With IR-ROM differences controlled for, significantly higher gluteus medius:adductor longus EMG activation ratio (F=4.32, p=0.046) was observed in the same phase in sFAI (0.16±0.34) compared to controls (−0.11±0.31). No other significant results were found. Conclusion. sFAI hips demonstrate altered muscle activation and movement patterns when ascending from seated positions compared to controls, with reduced hip IR-ROM in sFAI hips influencing findings. Abductor and adductor function imbalance may explain why sFAI increases risk of early degenerative changes. Despite study limitations (no imaging for sFAI diagnosis), these findings should be considered when optimising rehabilitation in this population. For any figures and tables, please contact the authors directly

Aims

The objective of this study was to investigate bone healing after internal fixation of displaced femoral neck fractures (FNFs) with the Dynamic Locking Blade Plate (DLBP) in a young patient population treated by various orthopaedic (trauma) surgeons.

Total knee arthroplasty (TKA) is an exceptionally successful and robust treatment for disabling knee disease, but many efforts continue to improve patient postoperative satisfaction and performance. One approach to improving performance is to restore TKA motions closer to those in healthy knees. Based upon an idealized model of knee motions, it is possible to design tibiofemoral articulating surfaces to promote natural kinematics and force transfer (Fiedler et al., Acta Bioeng Biomech, 2011). Such an asymmetric design is expected to promote rollback in stance phase that continues through deeply flexed activities. The purpose of this study is twofold: (1) To determine if a TKA designed on a theoretical basis achieves the proposed motions in vivo, and (2) To track postoperative kinematic patterns with examinations at 6–12 weeks, 6 months and one year postoperatively. This paper reports results of the initial cohort that has completed 6–12 week and 6-month examinations. Eight patients, including 3 females, with unilateral TKA for varus osteoarthritis provided written informed consent prior to beginning the study. Patients averaged 66±9 years, 168±14cm, and 28±3 BMI. Patients performed three weightbearing activities observed using pulsed x-ray flat-panel imaging at 30Hz: stepping up from flexion to extension on a 20cm step, lunging to maximum flexion with the foot placed on a 20 cm step, and kneeling to maximum flexion with the shin placed on a padded support. Three-dimensional knee kinematics were quantified using model-image registration to determine flexion, tibial internal rotation, anteroposterior movement of the femoral condyles (relative to the tibial AP center) and average center of rotation (CoR) in the transverse plane. During the maximum-flexion lunge and kneeling activities subjects exhibited average knee flexion of 104°–110° and tibial internal rotation of 2°–6° (Table 1). At 6–12 weeks, the medial/lateral condyles were at −3mm/−8mm and −1mm/−6mm during maximum flexion lunge and kneeling, respectively. During the stair activity from 0° to 70° flexion, there were small tibial internal rotations (1°/5°) and anterior medial (2mm/5mm) and lateral (3mm/3mm) condylar translations at both time points (Figure 1). The average CoRs for the stair activity were medial +18% and +5% for the 6–12 week and 6-month exams, respectively. It has long been assumed knee kinematics change during a patient's first one or two postoperative years. In our early post-op cohort, changes in weight-bearing kinematics over the first 6 postoperative months are small. In maximal flexion activities, patients exhibited flexion similar to similar cohorts studied at least one year post-op (Clin Orthop, 410:131–138, 2003). Similarly, kinematics during the weight-bearing step activity were similar in pattern and magnitude to those previously reported for posterior cruciate-retaining (CR) TKA at least one year post-op (Clin Orthop, 426:187–193, 2004). The average CoRs were medial for the stair activity, which is normal for healthy knees but uncommon for CR TKA. Early post-op results with an asymmetric CR TKA implant intended to promote physiologic motion show flexion and stair kinematics similar to many successful CR designs at longer follow-up. The medial CoR indicates closer-to-physiologic motion than commonly is observed in CR TKA

Aims

Computer hexapod assisted orthopaedic surgery (CHAOS), is a method to achieve the intra-operative correction of long bone deformities using a hexapod external fixator before definitive internal fixation with minimally invasive stabilisation techniques.

The aims of this study were to determine the reliability of this method in a consecutive case series of patients undergoing femoral deformity correction, with a minimum six-month follow-up, to assess the complications and to define the ideal group of patients for whom this treatment is appropriate.

Shortness of an extremity due to different causes is an issue that may adversely affect human life functional and psychologically. In this study, in the light of previous studies, it is aimed to develop a new expandable intramedullary system, providing lengthening in order to remove previous problems and complications and to annihilate leg length discrepancies at present and future without second surgical intervention as far as possibble by lenghtening the intramedullary nail. To this end, a new electromechanically activated intramedullary nail has been designed and generated. The intramedullary nail was designed to perform extremity lengthening electro-mechanically. The 3D design of the system is performed with computer software and the rapid and metal prototype of the system has been produced. The intramedullary nail system is comprised of three main units; Mechanical transmission unit, Electronic unit, Lengthening unit. The nail system is designed to function both mechanically and electronically complying with the requirement. This also provides an advantage that if any one (mechanic or electronic) fails, the lengthening process can continue with the other. Compression tests are applied in order to evaluate the strength of the system. The deformation values of the parts are recorded and stress values of each parts were calculated. The new system needs only 300N loading for mechanical lengthening. When 800N is considered as average human weight, the implant must withstand minumum 2400N load. Considering the safety conditions, we applied 4000N load on the new system. At 4000N, the whole system shows only 1.465 mm deformation which is less than the gap between the two bone parts. Also, when the system is implanted inside the bone, the loads are distributed proportionally between the bone and the implant. So, except for extraordinary conditions, the newly developed system is highly rigid and safe. In each applied method, lots of complications whether general or method-specific are seen. When the methods like Albizzia, ISKD and FITBONE avaliable and widely used today are examined separately, complications specific to these methods can be clearly observed [1–12]. Bliskunov Nail, Albizzia Nail and ISKD [13–18] have mechanical working principles and in these systems, lengthening process is obtained by rotational movement of the extremity. This rotational movement causes complications like pain, dislocation and uncontrolled lengthening [11,13,16,19–21]. In our newly developed system, only axial stimulation is needed for the activation of the mechanism. This is one of the advantages of our system. Both the mechanical unit and the electronical units are designed to be extended 0.1 mm at each activation. This means that the optimal amount of distraction (1mm/day) can be achieved in a controlled way. In other systems, the distraction amount can not be fully controlled and complications seen on other systems [1, 6, 8–10], like distruption of callus due to the excessive distraction and nonunion of the bone can be encountered. The success of the system at practice will be examined with in-vivo animal experiments and according to the results, it will be ready for use on human by performing necessary restorations

Introduction. Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femolo-tibial joint as well as posterior-stabilized (PS) polyethylene insert, even if PCL is sacrificed after TKA. The purpose of this study is an investigation of in vivo kinematics of femolo-tibial joint with use of CS polyethylene insert before and after PCL resction using computer assisted navigation system intra-operatively in TKA. Materials and Methods. Twenty-four consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker) were performed using computer assisted navigation system. In all patients, difference between extension and flexion gap was under 3mm after bony cut of femur and tibia. During surgery, CS polyethylene tibial trial insert were inserted after trial implantation of femoral and tibial components, before and after resection of PCL, respectively. The kinematic parameters of the soft-tissue balance, and amount of coronal (valgus/varus), sagittal (anterior/posterior) and rotational relative movement between femur and tibia were obtained by interpreting kinematics, which display tables throughout the range of motion (ROM) (Figure1). During record of kinematics, the surgeon gently lifted the experimental thigh three times, flexing the hip and knee. In each ROM (30, 45, 60, 90, max degrees), the data were analyzed with paired t-test, and an ANOVA test, and mean values were compared by the multiple comparison test (Turkey HSD test) (p < 0.05). Results. In coronal (valgus/varus) movement, there are no difference between before and after resection of PCL in all ROM. Regarding to amount of sagittal movement of tibia, tibia was slightly shifted approximately 0.75mm posteriorly in 60 degrees of flexion (p=0.013). There are no significance between before and after PCL resection in the other ROM. In addition, concerning ROM, maximum extension angle is significantly lower, and maximum flexion angle is significantly higher after than before PCL resection. Discussion. These results demonstrated that CS polyethylene insert might have a stability of femoro-tibial joint nearly after PCL resection as well as before PCL resection. The main design feature of Triathlon CS insert is single radius and rotary arc, in addition, the posterior lip is same as that of Triathlon CR, which can be the factor to avoid paradoxical anterior movement and to permit internal and external rotation between femoral and tibial component. This study was localized at point of certain situation that difference between extension and flexion gap is under 3mm after bony cut of femur and tibia during surgery. Due to the design features and benefits, there is a high possibility that use of CS insert without PCL can lead same stability as PCL remained, and improvement of ROM. Based on these backgrounds, it is suggested that CS insert may have an additional choice of PCL resection in case of tight gap of flexion in TKA

Background. A navigation system is useful tool to evaluate the intraoperative knee kinematics. Rheumatoid arthritis (RA) patients often need to have TKA operation, however, there are few TKA kinematics studies comparing RA and Osteoarthritis (OA) patients. Objective. The purpose of this study was to evaluate intraoperative TKA kinematics, and to describe the difference of kinematics between RA and OA patients. Materials and methods. Seventy-four patients, 86 knees were included in this study. Unilateral posterior stabilized TKAs were performed (male 14, female 72, age 70 ± 1.1 years) using navigation system. Sixty-one knees had OA and 25 had RA. Evaluation items are coronal gaps, AP translation and rotation. Coronal gaps were defined as the distance between the femoral and tibial cut surface. Medial and lateral gaps are also measured. AP translation was defined as the sagittal movement between the center of femoral and tibial condyle. Rotation was defined as axial difference of axis between femur and tibia. All items were evaluated by navigation system at every 10 degrees of knee flexion from 0 degrees of extension to 140 degrees of deep flexion. Results. In extension range, mean medial joint gaps (RA / OA) were 22.5 / 21.6 mm at 0 degree and decreased to 17.3 /15.0mm at 40 degrees, respectively. They were significantly different at 40 degrees. Lateral joint gaps were 16.4, 15.5mm at zero degree and slightly decreased to 21.0 / 20.0 mm at 40 degrees. In flexion range, mean medial joint gaps were 17.3 / 17.2 mm, 20.9 / 21.6 mm and 34.9 / 37.3 mm at 50 / 90 mm and 140 degrees. Mean lateral joint gaps were 16.4 / 15.5 mm, 21.8 / 21.6 mm and 29.0 / 31.4 mm. Both gaps were increased as knee was bent deeply(see Figure 1). Regarding to AP translation, femoral component was once moved 6.5 / 6.1 mm forward up to 50 degrees, then moved 25.8 / 23.5 mm backward with flexion. There was no significant difference (see Figure 2). Rotation kinematics showed significant difference in early flexion range. Consecutive external rotation of femur was recognized in RA group, but internal rotation was occurred in OA group from 0 to 60 degrees. External rotation was recognized in both groups from 60 degrees to deep flexion (see Figure 3). Conclusion. In this study, although joint gaps and AP translation were almost similar between RA and OA, it became clear that most significant difference was rotation movement in early range of knee flexion. It recognized opposite rotation between two groups. The limitation of this study was the situation of under anesthesia and no muscle strain were loaded during the measurement of knee kinematics. However, navigation system is available not only for the accurate implantation but also the measurement of intra operative knee kinematics

Introduction. The low-contact stress (LCS) knee prosthesis is a mobile-bearing design with modifications to the tibial component that allow for meniscal-bearing (MB) or rotating-platform (RP). The MB design had nonconstrained anteroposterior and rotational movement, and the RP design has only nonconstrained rotational movement. The anterior soft tissues, including patellar tendon (PT), prevent anterior dislocation of the MB. The PT may consistently be exposed to overstressing. Therefore, we hypothesized that the PT thickness and width in MB prosthesis revealed more morphological changes than those of RP prosthesis due to degeneration of the PT induced by much mechanical stress of the MB movement. To confirm this hypothesis, we analyze the PT thickness and width induced by mobile-bearing inserts. Objectives. Sixty LCS prostheses in 30 patients were analyzed. The average follow-up time was 61 months. MB prosthesis was used on one side of the knee and RP prosthesis was used on the contralateral side of the knee. All patients were chosen from group with no clinical complication, and all had achieved passive full extension and at least 90°of flexion. The average Hospital for Special Surgery Score was 94.6 ± 2.7. Methods. We measured the thickness and width of PT at joint line level, which were confirmed by sagittal section using ultrasound in knee extension between MB and RP design prosthesis. Results. The mean thickness of PT was 4.7 mm (1.2) with MB and 4.7 mm (1.0) with RP design prosthesis. The mean width of PT was 30.6 mm (3.2) with MB and 31.3 mm (3.5) with RP design prosthesis. No significant differences were found between both groups. Conclusion. The current results showed that the PT thickness and width in MB prosthesis did not reveal more morphological changes than those of RP prosthesis due to degeneration of the PT induced by much mechanical stress of the MB movement. The possible reasons are the following: (1) We did not remove infra-patellar fat pad, which might play shock absorber of mechanical stress from MB, and prevent from significant degeneration of PT, (2) MB inserts did not stimulate the middle of the PT directly, unlike LCS A/P-Glide inserts, and might come into contact with the both ends of the PT and (3) MB inserts did not move so as to cause degeneration in the PT

The interaction between the lumbosacral spine and the pelvis is dynamically related to positional change, and may be complicated by co-existing pathology. This review summarises the current literature examining the effect of sagittal spinal deformity on pelvic and acetabular orientation during total hip arthroplasty (THA) and provides recommendations to aid in placement of the acetabular component for patients with co-existing spinal pathology or long spinal fusions. Pre-operatively, patients can be divided into four categories based on the flexibility and sagittal balance of the spine. Using this information as a guide, placement of the acetabular component can be optimal based on the type and significance of co-existing spinal deformity.

Cite this article: Bone Joint J 2015;97-B:1017–23.