Background

Total Shoulder Arthroplasty (TSA) has been shown to improve the function and pain of patients with severe degeneration. Recently, TSA has been of interest for younger patients with higher post-operative expectations; however, they are treated using traditional surgical approaches and techniques, which, although amenable to the elderly population, may not achieve acceptable results with this new demographic. Specifically, to achieve sufficient visualization, traditional TSA uses the highly invasive deltopectoral approach that detaches the subscapularis, which can significantly limit post-operative healing and function. To address these concerns, we have developed a novel surgical approach, and guidance and instrumentation system (for short-stemmed/stemless TSA) that minimize muscle disruption and aim to optimize implantation accuracy.

Development

Surgical Approach: A muscle splitting approach with a reduced incision size (∼6–8cm) was developed that markedly reduces muscle disruption, thus potentially improving healing and function. The split was placed between the infraspinatus and teres-minor (Fig.1) as this further reduces damage, provides an obvious dissection plane, and improves access to the retroverted articular surfaces. This approach, however, precludes the use of standard bone preparation methods/instruments that require clear visualization and en-face articular access. Therefore, a novel guidance technique and instrumentation paradigm was developed.

Minimally Invasive Surgical Guidance: 3D printed Patient Specific Guides (PSGs) have been developed for TSA; however, these are designed for traditional, highly invasive approaches providing unobstructed access to each articular surface separately. As the proposed approach does not offer this access, a novel PSG with two opposing contoured surfaces has been developed that can be inserted between the humeral and scapular articular surfaces and use the rotator cuff's passive tension to self-locate (Fig.2). During computer-aided pre-operative planning/PSG design, the two bones are placed into an optimized relative pose and the PSG is constructed between and around them. This ensures that when the physical PSG is inserted intra-operatively, the bones are locked into the preoperatively planned pose.

New Instrumentation Paradigm: With the constraints of this minimally invasive approach, a new paradigm for bone preparation/instrumentation was required which did not rely on en-face access. This new paradigm involves the ability to simultaneously create glenoid and humeral guide axes – the latter of which can guide humeral bone preparation and be a working channel for tools – by driving a short k-wire into the glenoid by passing through the humerus starting laterally (Fig.3). By preoperatively defining the pose produced by the inserted PSG as one that collinearly aligns the bones’ guide axes, the PSG and an attached c-arm drill guide facilitate this new lateral drilling technique. Subsequently, bone preparation is conducted using novel instruments (e.g. reamers and drills for creating holes radial to driver axis) powered using a trans-humeral driver and guided by the glenoid k-wire or humeral tunnel.

Introduction

Total hip arthroplasty has become an increasingly common procedure. Improper cup position contributes to bearing surface wear, pelvic osteolysis, dislocations, and revision surgery. The incidence of cup malposition outside of the safe zone (40° ± 10° abduction and 15° ± 10° anteversion) using traditional techniques has been reported to be as high as 50%. Our hypothesis is that computer assisted navigation will improve cup placement in total hip arthroplasty compared with traditional techniques.

Methods

This study retrospectively evaluated the position of 425 consecutive cups placed during primary total hip arthroplasty performed over a two-year period, from 8/1/2012 to 8/1/2014. All cups were placed with a direct-anterior muscle-sparing approach with computer-assisted imageless navigation by a single surgeon. Real-time intraoperative “screen shots” were taken of cup placement. Standard antero-posterior postoperative radiographs of the pelvis were taken within 6 weeks of surgery in the operating surgeon's office using the same standardized protocol for each patient. The radiographs were evaluated by two separate investigators for final abduction and anteversion utilizing the same method as other studies. Statistics were descriptive in nature.

INTRODUCTION

The Articular Surface Replacement XL system (ASRXL) with metal-on-metal (MoM) of the articular surfaces was produced by DePuy Orhopaedics since 2003 for total hip replacement. In 2010 following the notification received from the National Joint Registry (NJR) of England and Wales concerning the excessive failure rate of the ASR system (approximately 13% at 5 years), the DePuy send the recall of the product. All operated patients were checked.

MATERIALS AND METHODS

We enrolled in our Followup 106 patients (51 males, 55 females, mean age 63.6) with a total of 107 implants (one is a bilateral case), subjected with clinical and instrumental investigations.

The controls were performed annually; for the patients who presented positive clinical-instrumental condictions and values of Chromium (Cr) and Cobalt (Co)> 7 mg /l it has been proposed followup closer, every 6 months for the entire life of the implant.

For the evaluation of the cases in our study, we used the following scales:

Clinical Score: Harris Hip Score (pain and functional limitation)

The analysis of ionemia was made at the Clinical Chemistry at Charing Cross Hospital in London.

Introduction

Acetabular reconstruction of a total hip arthroplasty (THA) for a case with severe bone loss is most challenging for surgeon. Relatively high rate of failure after the reconstruction surgery have been reported. We have used Kerboull-type acetabular reinforcement devices with morsellised or bulk bone allografts for these cases. The purpose of this study was to examine the midterm results of revision THA using Kerboull-type acetabular reinforcement devices.

Patients and methods

We retrospectively reviewed 20 hips of revision THA (20 patients) between February 2002 and August 2010. The mean age of the patients at the time of surgery was 67.4 years (range 45–78). All of the cases were female. The mean duration of follow-up was 6.5 years (range 2.1–10.4). The reasons of revision surgeries were aseptic loosening in 10 hips, migration of bipolar hemiarthroplasty in 8 hips, and rheumatoid arthritis in 2 hips. We classified acetabular bone defects according to the American Academy of Orthopaedic Surgeons (AAOS) classification; we found two cases of Type II and eighteen cases of Type III. In terms of bone graft, we performed both bulk and morsellised bone grafts in 6 hips and morsellised bone grafts only in 14 hips. We assessed cup alignment using postoperative computed tomography (CT) and The post-operative and final follow-up radiographs were compared to assess migration of the implant. We measured the following three parameters: the angle of inclination of the acetabular device (Fig. 1); the horizontal migration (Fig. 2a); and vertical migration (Fig. 2b). Substantial migration was defined as a change in the angle of inclination of more than 3 degrees or migration of more than 3 mm. The pre- and postoperative hip functions were evaluated using the Japanese Orthopaedic Association (JOA) hip score.

Background

Composite screws of uncalcined and unsintered hydroxyapatite (HA) particles and poly-l-lactide (PLLA) were developed as completely absorbable bone fixation devices. So far the durability of HA-PLLA composite screws is unclear when used for the fixation of acetabular bone graft in total hip arthroplasty under full-weight conditions. We have used this type of screw for the fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty since 2003. Hence, we conducted a follow-up study to assess the safety and efficacy of these screws when used for cemented socket fixation.

Methods

During 2003–2009, HA-PLLA composite screws were used for fixation of acetabular bone graft in cemented or reverse-hybrid primary THA in 106 patients (114 cases). All the THAs were performed through direct lateral approaches, and postoperative gait exercise with full weight bearing usually started two days after surgery. One patient died of an unrelated disease and seven patients were lost to follow-up within 5 years. Finally, 98 patients (106 cases) were followed up for over 5 years and were reviewed retrospectively (follow-up rate, 93%). Radiographic loosening of the acetabular component was assessed according to the criteria of Hodgkinson et al., and the radiolucent line around the socket was evaluated in all zones, as described by DeLee and Charnley.

Introduction

The General Social Survey estimates that 19 million Americans shoot firearms, with 10% of this population being over the age of 65. More reverse total shoulder arthroplasty (rTSA) are seeking to return to physical activity after surgery, but the effects of shooting a firearm on the fixation of a rTSA implant are unknown. This study will seek to examine the recoil effect of a firearm on a rTSA baseplate fixation, by recording the forces absorbed by a shooter and applying these forces to a rTSA implant assembly in laboratory conditions.

Methods

A total of 5 shooters over a range of heights and bodyweights fired a single action 12 gauge shotgun with 3 ounce slugs 5 times each. An accelerometer was rigidly fixated to the barrel of the firearm to record impulse values upon firing. 8 reverse shoulder baseplate/glenosphere assemblies (Equinoxe, Exactech, Inc) were fixated to 15 lb/ft3 density rigid polyurethane bone substitute blocks for drop tower testing. Displacement was measured before and after testing using digital displacement indicators by applying a physiologically relevant 357N shear load parallel to the face of the glenosphere, and a nominal 50N compressive axial load perpendicular to the glenosphere as shown in Figure 1. Measurements were taken for the S/I axis, and the sample was rotated 90 degrees for the A/P axis. The glenosphere/baseplate assemblies were loaded in a drop tower apparatus at 0° of abduction and 90° flexion to replicate the orientation of the joint seen while shooting. The drop tower utilized a 1.079kg weight set at 8” with a rubber impulse specific materil between the weight and impactor to reproduce the highest average impulse seen in shooting. A total of 50 drops were performed, to simulate two rounds of trap shooting at 25 shots each. A Student's one-tailed, paired t-test was used to identify whether or not significant loosening occurred, where p<0.05 denoted a significant difference.

Introduction

Reverse Total Shoulder Arthroplasty (rTSA) is currently advised against in patient populations with movement disorders, due to potential premature failure of the implants from the use of walking assistive devices. The objective of this study is to measure the amount of displacement induced by the simulated loading of axillary crutches on a rTSA assembly in a laboratory mimicking immediate postoperative conditions.

Methods

8 reverse shoulder baseplate/glenosphere assemblies (Equinoxe, Exactech, Inc) were fixated to 15 lb/ft3 density rigid polyurethane bone substitute blocks. Displacement of the assemblies in the A/P and S/I axes was measured using digital displacement indicators by applying a physiologically relevant 357N shear load parallel to the face of the glenosphere, and a nominal 50N compressive axial load perpendicular to the glenosphere. Westerhoff et al. reported in vivo shoulder loads while ambulating with axillary crutches had a maximum resultant force of 170% times the patient's bodyweight with the arm at 45.25° of abduction1. This was recreated by applying a 1435.4N compressive load (Average bodyweight of 86.1kg*170%) to a humeral liner and reverse shoulder assembly in an Instron testing apparatus at 45.25° of abduction as shown in Figure 1. The glenosphere was rotated about the humeral component through the arc of the axillary crutch swing, from −5° of extension to 30° of flexion as shown in Figure 2 for 183,876 cycles2. The number of cycles was based on number of steps taken in a day from pedometer data reported by Tudor Locke et al. for patients with movement disorders, extrapolated out to a 6 week postoperative recovery period3. A Student's one-tailed, paired t-test was used to identify whether or not significant displacement occurred, where p<0.05 denoted a significant difference.

Introduction

The goal of total hip arthroplasty (THA) is to reduce pain, restore function but also activity levels for general health benefits or social participation. Thus evaluating THA patient activity can be important for diagnosis, indication, outcome assessment or biofeedback.

Methods

Physical activity (PA) of n=100 primary THA patients (age at surgery 63 ±8yrs; 49M/51F; 170 ±8cm, 79.8 ±14.0kg) was measured at 8 ±3yrs follow-up. A small 3D accelerometer was worn for 4 successive days during waking hours at the non-affected lateral upper leg. Data was analyzed using validated algorithms (Matlab) producing quantitative (e.g. #steps, #transfers, #walking bouts) and qualitative (e.g. cadence, temporal distribution of events) activity parameters. An age matched healthy control group (n=40, 69 ±8yrs, 22M/18F) served as reference.

Introduction

Unicompartmental knee arthroplasty is in particular promoted for knee OA patients with high demands on function and activity. This study used wearable inertial sensors to objectively assess function during specific motion tasks and to monitor activities of daily living to verify if UKA permits better function or more activity in particular with demanding tasks.

Methods

In this retrospective, cross-sectional study, UKA patients (Oxford, n=26, 13m/13f, age at FU: 66.5 ±7.6yrs) were compared to TKA patients (Vanguard, n=26, 13m/13f, age: 66.0 ±6.9yrs) matched for gender, age and BMI (29.5 ±4.6) at 5 years follow-up.

Subjective evaluation of pain, function, physical activity and awareness of the joint arthroplasty was performed by means of four PROMs: VAS pain, KOOS-PS, SQUASH (activity) and Forgotten Joint Score (FJS),

Objective measurement of function was performed using a 3D inertia sensor attached to the sacrum while performing gait test, sit-stand and block-step tests. To derive functional parameters such as walking cadence or sway during transfers or step-up previously validated algorithms were used (Bolink et al., 2012).

Daily physical activity was objectively monitored with a 3D accelerometer attached to the lateral side of the unaffected upper leg during four consecutive days. Activity parameters (counts and times of postures, steps, stairs, transfers, etc.) were also derived using validated algorithms. Data was analysed using independent T-test, Mann-Whitney U test and Pearson's correlation.

INTRODUCTION

Highly cross-linked polyethylene (XLPE) inserts have shown significant improvements in decreasing wear and osteolysis in total hip arthroplasty [1]. In contrast to that, XLPE has not shown to reduce wear or aseptic loosening in total knee arthroplasty [2,3,4].

One major limitation is that current wear testing in vitro is mainly focused on abrasive-adhesive wear due to level walking test conditions and does not reflect “delamination” as an essential clinical failure mode [5,6].

The objective of our study was to use a highly demanding daily activities wear simulation to evaluate the delamination risk of polyethylene materials with and without vitamin E stabilisation.

MATERIALS & METHODS

A cruciate retaining fixed bearing TKA design (Columbus® CR) with artificially aged polyethylene knee bearings (irradiation 30 & 50 kGy) blended with and without 0.1% vitamin E was used under medio-lateral load distribution and soft tissue restrain simulation. Daily patient activities measured by Bergmann et al. [7] in vivo, were applied for 5 million knee wear cycles in a combination of 40% stairs up, 40 % stairs down, 10% level walking, 8% chair raising and 2% deep squatting with up to 100° flexion [8] (Fig. 1).

The specimens were evaluated for gravimetric wear and analysed for abrasive-adhesive and delamination wear modes.

Objective

In this study, we aim to compare total bone amount extracted in total knee arthroplasty in implant design and the bone amount extracted through intercondylar femoral notch cut.

Material and Method

In this study, we implemented 10 implants on a total of 50 sawbones from 5 different total knee arthroplasty implant brands namely Nex-Gen Legacy (Zimmer, Warsaw, IN, USA), Genesis 2 PS (Smith&Nephew, Memphis, TN, USA), Vanguard (Biomet Orthopedics Inc., Warsaw, IN, USA), Sigma PS (De Puy, Johnson&Johnson, Warsaw, IN, USA), Scorpio NRG PS (Stryker Co., Kalamazoo, USA). Equal or the closest sizes of each brand on anteroposterior plane were selected, and cuts were made following standard technique(see Fig 1 and 2). Extracted bone pieces were measured in terms of volume and length on three planes, and statistically analysed. The volume of all pieces available after each femoral incision was measured according to Archimedes’ principles. Furthermore, the volume of each intercondylar femoral notch pieces was measured separately from other pieces but with the same method. The measurement of intercondylar femoral notch pieces on 3 planes (medial-lateral, anterior-posterior, superior-inferior) was made using Kanon slide gauge (Ermak Ltd, Istanbul, TR). Femoral notch incision pieces were scanned with CAD/CAM technology using three-dimensional scanner 1 SeriesTM (Dental Wings Inc, Montreal, QC, Canada), and the measurements were confirmed with DWOS CAD 4.0.1 software (Dental Wings Inc, Montreal, QC, Canada)(see figure 3a-e). The volume of 10 intercondylar femoral notch pieces performed through the set of each brand was averaged, and considered as the incision volume of that particular brand.

Introduction

Modular hip replacement systems use Morse tapers as an interlocking mechanism to connect ball heads to femoral stems. Even though this interlocking mechanism generally performs successfully for decades, failures due to disassociation of the ball head from the stem are reported in the literature. Therefore, this failure mechanism of a possible loosening is usually evaluated in the course of the development of femoral stems. The disassembly force is a possible parameter to characterize the strength of the interlocking mechanism. Thus, the aim of the current study was to examine the impact of different taper parameters on the disassembly force of ceramic ball heads from titanium stem tapers by finite element studies.

Materials and Methods

A 2D axisymmetric finite element model was developed to simulate the disassembly procedure. First ball head and taper were assembled with a force of 4 kN. Afterwards the system was unloaded to simulate the settlement. Disassembly was simulated displacement controlled until no more adhesion between ball head and taper occurred. Isotropic elastic material behavior was modelled for the ceramic ball head while elastic-plastic material behavior was modelled for the titanium taper. Different angular gaps (0.2°, 0.15°, 0.1°, 0.05°, 0°, −0.05°, −0.1°) and different taper topography parameters regarding groove depth (12, 15 µm), groove distance (210, 310 µm) and plateau width (1, 5, 10, 20 µm) were examined. Frictional contact between ball head and taper was modelled.

Introduction

Modular acetabular liners are fixed in metal shells by a taper locking mechanism. Male tapers of the liner and female tapers of the metal shell have different taper angles resulting in an angular gap. Depending on the specific manufacturing tolerances varying angular gaps may result and, thus, different contact mechanics may be generated that could alter the stresses within the acetabular liner. Therefore, the aim of the current study was to experimentally determine stresses in a ceramic liner depending on different angular gaps under in vivo like loading conditions.

Materials and Methods

Two ceramic liners were instrumented at the outer contour with five strain gauge (SG) rosettes each (Fig.1). First, metal shells were axially seated in an asymmetric press-fit model with 0.5 mm under-reaming, then liners were assembled with a 2 kN axial load. SG5 was placed at the flat area of the liner, the other four were placed circumferentially in 90 degrees offset on the rear side. SG2 and SG4 were mounted opposite to each other in press-fit direction while SG1 and SG3 were placed in the non-supported direction. Three inclination angles (0°, 30°, 45°) were tested under in vivo relevant loads of 4.5 and 11 kN. Four positive angular gaps (A1=0.162°±0.007°, A2=0.084°±0.002°, A3=0.054°±0.004°, A4=0.012°±0.005°) and one negative angular gap (A5=−0.069°±0.006°) were examined. For all tests a mid-tolerance clearance between liner and ball head of 70 µm was chosen. Strain data were converted to stresses and compared using a paired 2-sided Wilcoxon Signed Rank Test at an α-level of 0.05.

Background

The knee joint morphology varies according to gender and morphotype of the patients.

Objectives

To measure the dimensions of the proximal tibia and distal femur of osteoarthritic knees in a group of patients from the same ethnic group (Arabs) and to compare these measurements with the dimensions of six total knee implants.

INTRODUCTION

Understanding the relationship between knee specific tissue behavior and joint contact mechanics remains an area of focus. Seminal work from 1990's established the possibility to optimize tissue properties for recreation of laxity driven kinematics (Mommersteeg et al., 1996). Yet, the uniqueness and validity of such predictions could be strengthened, especially as they relate to joint contact conditions. Understanding this interplay has implications for the long term performance of joint replacements.

Development of instrumented knee implants, highlighted by a single use tibial insert trial with embedded sensor technology (VERASENSE, Orthosensor Inc.), may offer an avenue to establish the relationship between tissue state and joint mechanics. Utilization of related data also has the potential to confirm computational predictions, where both rigid body motions and associated reactions are explicitly accounted for. Hence, the goal of this work was to evaluate an approach for optimization of ligament properties using joint mechanics data from an instrumented implant during laxity style testing. Such a framework could be used to inform joint balancing techniques, improve long term implant performance, and alternatively, qualify factors that may lead to poor outcomes

METHODS

Experimentation was performed on a 52 year old male, left, cadaveric specimen. Joint arthroplasty was performed using standard practice by an experienced orthopedic surgeon. To mimic passive intraoperative loading, laxity loading at 10°, 45° and 90° flexion, which consisted of discrete application of anterior-posterior (± 100N), varus-valgus (± 5 Nm) and internal-external (± 3 Nm) loads at each angle, was performed using a simVITROTM robotic musculoskeletal simulator (Cleveland Clinic, Cleveland, OH). Experimental results included relative tibiofemoral kinematics and sensor measured metrics (Fig 1).

The finite element model was developed from specimen-specific MRIs and solved using Abaqus/Explicit. The model included the rigid bones, appropriately placed implants and relevant soft-tissue structures (Fig. 1). Ligament stiffness values were adopted from the literature and included a 6% strain toe region. Sets of nonlinear springs, defined using MR imaging, comprised each ligament/bundle. Optimization was performed, which minimized the root mean squared difference between VERASENSE measured tibiofemoral mechanics and the model predicted values. Ligament slack lengths were the control variables and the objective included each loading state and all contact metrics (θ, AFD, ML, and LL).

Introduction

Improper soft-tissue balancing can result in postoperative complications after total knee arthroplasty (TKA) and may lead to early revision. A single-use tibial insert trial with embedded sensor technology (VERASENSE from OrthoSensor Inc., Dania Beach, FL) was designed to provide feedback to the surgeon intraoperatively, with the goal to achieve a “well-balanced” knee throughout the range of motion (Roche et al. 2014). The purpose of this study was to quantify the effects of common soft-tissue releases as they related to sensor measured joint reactions and kinematics.

Methods

Robotic testing was performed using four fresh-frozen cadaveric knee specimens implanted with appropriately sized instrumented trial implants (geometry based on a currently available TKA system). Sensor outputs included the locations and magnitudes of medial and lateral reaction forces. As a measure of tibiofemoral joint kinematics, medial and lateral reaction locations were resolved to femoral anterior-posterior displacement and internal-external tibial rotation (Fig 1.). Laxity style joint loading included discrete applications of ± 100 N A-P, ± 3 N/m I-E and ± 5 N/m varus-valgus (V-V) loads, each applied at 10, 45, and 90° of flexion. All tests included 20 N of compressive force. Laxity tests were performed before and after a specified series of soft-tissue releases, which included complete transection of the posterior cruciate ligament (PCL), superficial medial collateral ligament (sMCL), and the popliteus ligament (Table 1). Sensor outputs were recorded for each quasi-static test. Statistical results were quantified using regression formulas that related sensor outputs (reaction loads and kinematics) as a function of tissue release across all loading conditions. Significance was set for p-values ≤ 0.05.

Introduction

Computer-assisted orthopaedic surgery (CAOS) has been shown to assist in achieving accurate and reproducible prosthesis position and alignment during total knee arthroplasty (TKA) [1]. The most prevalent modality of navigator tracking is optical tacking, which relies on clear line-of-sight (visibility) between the localizer and the instrumented trackers attached to the patient. During surgery, the trackers may not always be optimally positioned and orientated, sometimes forcing the surgeon to move the patient's leg or adjust the camera in order to maintain tracker visibility. Limited information is known about tracker visibility under clinical settings. This study quantified the rotational limits of the trackers in a contemporary CAOS system for maintaining visibility across the surgical field.

Materials and Methods

A CAOS system (ExactechGPS®, Blue-Ortho, Grenoble, FR) was set up in an operating room by a standard surgical table according to the manufacture's recommendation. A grid with 10×10 cm sized cells was placed at the quadrant of the surgical table associated with the TKA surgical field [Fig. 1A,B]. The localizer was set up to aim at the center of the grid. A TKA surgical procedure was then initiated using the CAOS system. Once the trackers-localizer connection was established, the CAOS system constantly monitored the root mean square error (RMS) of each tracker. The connection was immediately aborted if the measured RMS was above the defined threshold. Therefore, “visibility” was defined as the tracker-localizer connection with proper accuracy level. An F tracker from the tracker set (3 trackers with similar characteristics) was placed at the center of each cell by a custom fixture, facing along the +Y axis [Fig. 1]. The minimum and maximum angles of rotation around the Z axis (RAZ_MIN and RAZ_MAX) and X axis (RAX_MIN and RAX_MAX) for maintaining tracker visibility were identified. For each cell, the rotational limit of the tracker was calculated for each axis of rotation as the difference between the maximum and minimum angles (RLX and RLZ).

Introduction

While total knee arthroplasty (TKA) improves postoperative function and relieves pain in the majority of patients with end stage osteoarthritis, its ability to restore normal knee kinematics is debated. Cadaveric studies using computer-assisted orthopaedic surgery (CAOS) system [1] are one of the most commonly used methods in the assessment of post-TKA knee kinematics. Commonly, these studies are performed with an open arthrotomy; which may impact the knee kinematics. The purpose of this cadaveric study was to compare the knee kinematics before and after (open or closed) arthrotomy.

Materials and Methods

Kinematics of seven non-arthritic, fresh-frozen cadaveric knees (PCL presumably intact) was evaluated using a custom software application in an image-free CAOS system (ExactechGPS, Blue-Ortho, Grenoble, FR). Prior to the surgical incision, one tracker was attached to the diaphysis of each tibia and femur. Native intact knee kinematics was then assessed by performing passive range of motion (ROM) three separate times, from full extension to at least 110 degrees of flexion, with the CAOS system measuring and recording anatomical values, including flexion angle, internal-external (IE) rotation and anterior-posterior (AP) translation of the tibia relatively to the femur, and the hip-knee-ankle (HKA) angle. Next, an anterior incision with a medial parapatellar arthrotomy was performed, followed by acquisition of the anatomical landmarks used for establishing an anatomical coordinate system in which all the anatomical values were evaluated [2]. The passive ROM test was then repeated with closed and then open arthrotomy (patella manually maintained in the trochlea groove). The anatomical values before and after knee arthrotomy were compared over the range of knee flexion using the native knee values as the baseline.

Introduction

One main perceived drawback for the adoption of computer assisted orthopedic surgery (CAOS) during total knee arthroplasty (TKA) relates to the increased surgical time compared to the use of standard mechanical instrumentation [1]. This study compared the time efficiency between a next generation CAOS system (ExactechGPS®, Blue-Ortho, Grenoble, FR) and conventional mechanical instrumentation, and assessed the impact of surgeon experience level on the efficiency.

Materials and methods

Surgical time was retrospectively reviewed on 63 primary TKAs performed by a board-certified orthopedic surgeon (PP) using a cemented postero-stabilized knee system (Optetrak Logic PS, Exactech, Gainesville, FL), grouped as 1) Group I (control): 21 TKAs using conventional mechanical instruments; 2) Group II: 21 TKAs performed using the CAOS system with an early experience level (first 21 cases); and 3) Group III: 21 TKAs using the CAOS system with an advanced experience level (beyond 30 cases). Surgical time was compared across the three groups (with significance defined as p<0.05).

Introduction

Computer-assisted orthopaedic surgery (CAOS) has been shown to help achieve accurate, reliable and reproducible prosthesis position and alignment during total knee arthroplasty (TKA) [1]. A typical procedure involves inputting target resection parameters at the beginning of the surgery and measuring the achieved resection after bone cuts. Across CAOS systems, software/hardware design, mechanical instrumentation, and system-dependent work flow may vary, potentially affecting the intraoperative measurement of the achieved resection. This study assessed the cumulative effect of system-dependent differences between two CAOS systems by comparing the alignment deviation between the measurement of the achieved resection and the targeted parameters.

Materials and Methods

TKA resections were performed on 10 neutral whole leg assemblies (MITA knee insert and trainer leg, Medial Models, Bristol, UK) by a board-certified orthopaedic surgeon (BH) using System I (5 legs, ExactechGPS®, Blue-Ortho, Grenoble, FR) and System II (5 legs, globally established manufacturer). The surgeon was deemed as “experienced” user (>30 surgeries) with both systems. The target parameters for the TKA resections, as well as major differences between the two systems are summarized in Table 1A. The deviations of the intraoperative alignment measurements on the achieved distal femoral and proximal tibial resection from the target were calculated and compared between the two systems with significance defined as p<0.05.

Background

Continuous epidural anesthesia or femoral nerve block has decreased postoperative pain after total knee arthroplasty to some extent. Although the established efficacy of these pain relief method, some adverse events such as hematoma or muscle weakness are still problematic. Intraoperative local infiltration of analgesia (LIA) has accepted as a promising pain control method after total knee arthroplasty. The safety and efficacy of LIA has been reported, although there are still limited evidence about the effect of LIA on quadriceps function and recovery of range of motion in early post-operative phase. The purpose of this study is to compare the quadriceps function and range of motion after TKA between the LIA with continuous epidural anesthesia and continuous epidural anesthesia alone.

Methods

Thirty patients with knee osteoarthritis who underwent primary TKA were included in this study. Patients who took anticoagulants were treated continuous epidural anesthesia alone (n=11) and the other patients were treated with LIA with continuous epidural anesthesia (n=19). A single surgeon at our department performed all surgeries. Surgical procedure and rehabilitation process was identical between two groups. Before the implantation, analgesic drugs consisting of 20 ml of 0.75 % ropivacaine and 6.6 mg of dexamethasone were injected into the peri-articular tissues. In each group, fentanyl continuous epidural patient-controlled analgesia (PCA) was also used during 48-h post-operative period. Knee flexion and extension angle were evaluated before surgery, post-op day 3, 7, 10 and 14. The quadriceps function was evaluated by quadriceps peak torque at 30° and 60° flexion using VIODEX. The peak torque was recorded preoperatively, day 14 and 3 month after surgery. The difference between two groups was analyzed by Mann Whitney U-test using Prism 6, a statistical software.

INTRODUCTION

Golf is considered low-impact sport, but concerns exist about whether golf swing can be performed in safe manner after THA. The purpose of this study was to clarify dynamic hip kinematics during golf swing after THA using image-matching techniques.

METHODS

This study group consisted of eight right-handed recreational golfers with 10 primary THAs. Each operation was performed using a posterolateral approach with combined anteversion technique. Nine of ten polyethylene liners used had elevated portion of 15°. Continuous radiographic images of five trail and five lead hips during golf swing were recorded using a flat panel X-ray detector (Fig. 1) and analyzed using image-matching techniques (Fig. 2). The relative distance between the center of cup and femoral head and the minimum liner-to-stem distance were measured using a CAD software program. The cup inclination, cup anteversion, and stem anteversion were measured in postoperative CT data. Hip kinematics, orientation of components, and cup-head distance were compared between patients with and without liner-to-stem contact by Mann-Whitney U test.

Introduction

Initial large-scale clinical studies of porous tantalum implants have been generally promising with well-fixed implants and few cases of loosening [1–3]. An initial retrieval study suggests increased bone ingrowth in a modular tibial tray design compared to the monoblock design [4]. Since micromotion at the bone-implant interface is known to influence bone ingrowth [5], the goal of this study was to determine the effect of implant design, bone quality and activity type on micromotion at the bone-implant interface, through FE modeling.

Patients & Methods

Our case-specific FE model of bone was created from CT data (68 year-old female, right tibia, Fig-1). Isotropic properties of cortical and trabecular bone were derived from the calibrated CT data. Modular and monoblock porous tantalum tibial implants were virtually placed in the tibia following surgical guidelines. All models parts were 3D meshed with 4-noded tetrahedral elements (MSC.MARC-Mentat 2013, MSC Software Corporation, USA). Frictional contact was applied to the bone-tantalum interface (µ=0.88) and UHWMPE-Femoral condyle interface (µ=0.05) with all other interfaces bonded. Loading was applied to simulate walking, standing up and descending stairs. For each activity, a full load cycle [6] was applied to the femoral condyles in incremental steps. The direction and magnitude of micromotions were calculated by tracking the motions of nodes of the bone, projected onto the tibial tray. Micromotions were calculated parallel to the implant surface (shear), and perpendicularly (tensile). We report the maximum (resultant) micromotion that occurred during a cycle of each activity. The bone properties were varied to represent a range in BMD (−30%BMD, Norm, +30%BMD). We compared design type, bone quality and activity type considering micromotion below 40 µm to be favorable for bone ingrowth [5].

Introduction

Wound condition after primary total knee arthroplasty (TKA) is important for prevention of periprosthetic infection. Any delay in wound healing will cause deep infection, which leads to the arthroplasty failure. Prevention of soft tissue problems is thus essential to achieve excellent clinical results. However, it is unknown as to the important surgical factors affecting the wound healing using detailed wound score after primary TKA so far.

It was hypothesized that operative technique would affect wound healing in primary TKA. The purpose of the present study was to investigate and to clarify the important surgical factors affecting wound score after primary TKA.

Methods

A total of 139 knees in 128 patients (mean 73 years) were enrolled. All primary TKAs were done by single surgeon. All patients underwent unilateral or bilateral TKA using Balanced Knee System®, posterior stabilized (PS) design (Ortho Development, Draper, UT) or Legion®, PS design (Smith and Nephew, Memphis, TN) under general and/or epidural anesthesia. Patients with immunosuppressive therapy, hypokalemia, poor nutrition (albumin < 3.4 g/dL), diverticulosis, infection elsewhere, uncontrolled diabetes mellitus (HbA1C>7.0%), obesity (Body Mass Index > 35 kg/m2), smoking, renal failure, hypothyroidism, alcohol abuse, rheumatoid arthritis, posttraumatic arthritis, and previous knee surgery were excluded. Hollander Wound Evaluation Score (HWES) was assessed on postoperative day 14. We evaluated age, sex, body mass index, HbA1C (%), preoperative femorotibial angle (FTA) on plain radiograph. In addition, intraoperative patella eversion, intraoperative anterior translation of the tibia, patella resurfacing, surgical time, tourniquet time, unidirectional barbed suture and length of skin incision were also evaluated as surgical factors. Multiple regression analysis was done using stepwise method to identify the surgical factors affecting HWES.

Introduction

A longer operative time will lead to the development of any postoperative complications in total knee arthroplasty (TKA). According to previous reports, a significant increase in TKA procedure time done by novice surgeons was observed compared to high-volume surgeons. Our purpose was to investigate and to clarify the important maneuver necessary for novice surgeons to minimize a surgical time in TKA.

Methods

A total of 300 knees in 248 patients, averaged 74.6 ± 8.7 years, were enrolled. All primary TKAs were done using same instruments (Balanced Knee System®, PS design, Ortho Development, Draper, UT) and same measured resection technique at 14 facilities by 25 orthopedic surgeons. Surgeons were divided into three surgeon groups (4 experts, 9 medium volume surgeons, 12 novices). All methods were approved by our institution's ethics committee.

We divided the operative technique into 5 steps to make comparisons of step-by-step surgical time among surgeon groups of different levels. We defined Phase 1 as performing surgical exposure from skin incision to insertion of the intramedullary rod into the femur. Thereafter, the distal and AP surface of the femur, proximal tibia, the chamfer and PS box of the femur, and patella were resected in Phase 2. In Phase 3, a setup the trial component and a keel of the tibia were done after a confirmation of appropriate ligament balance using the spacer block. Then, a bone surface was irrigated with 2000ml of saline after the removal of the trial component. Subsequently, permanent components were fixed with use of bone cement in Phase 4. Finally, the final irrigation using 2000ml saline and wound closure were done in Phase 5. Every phase of the surgical time was recorded in each TKA.

As a statistical analysis, operation data including length of skin incision, component size, operation time in each phase, and ratio of surgical time in each phase to whole surgical time, were compared using non-repeated measures of ANOVA and a post hoc Bonferroni correction. The threshold for statistical significance was set at a p value of less than 0.05.

Introduction

The trochlea of a typical patellofemoral replacement or anterior flange of a total knee replacement usually extends past the natural trochlea and continues onto the femoral anterior cortex. One reason for this is that it allows a simple patella button to be permanently engaged in the trochlea groove in an attempt to ensure stability. On the natural patella, the apex helps to guide it into the trochlea groove as the knee moves from full extension into flexion.

The aim is to study whether a generalised patella can be created that is close in form to a healthy patella.

Method

MRI scans were taken of 30 patellae. Characteristics of these patellae (height, width, thickness, apex angle) were measured. The apex angle was found to be similar between patellae (mean=126 degrees, sd = 8.8), as were the ratios between height and width (mean width/height = 1.05, sd = 0.07) and between thickness and width (mean width/thickness = 1.8, sd = 0.19).

These patellae were then segmented to create a surface including cartilage, resulting in 30 STL (stereolithography) files in which the surfaces are represented by triangle meshes.

To design the average patella the individual patellae were aligned to a standard frame of reference by placing a set of landmarks on the proximal/distal, medial/lateral and anterior/posterior extents of each (fig.1). The vertical axis was defined as passing parallel to the proximal/distal points and the horizontal as passing parallel to the medial/lateral points when looking along the computed vertical axis. The origin centre of the frame of reference was chosen to be mid-way between these points. The mean width was then computed and each patella scaled linearly around the origin to give them all equal width.

All the aligned patellae were then averaged together to provide a composite cartilaginous patella. The averaging process was achieved by taking one patella as a seed. The patella chosen for seed was that whose parameters were closest to the average width, height and thickness. An approximately normal vector was passed a point ‘P’ on the seeds, and the points at which these intersected the other models were then determined. The closest intersection point to ‘P’ on each model was chosen and these averaged together. ‘P’ is then replaced in the model with this average point. The averaging process then continues with all the remaining points on the seed model in the same manner to build the average models.

Introduction

Patient Specific Instrumentation (PSI) has the potential to allow surgeons to perform procedures more accurately, at lower cost and faster than conventional instrumentation. However, studies using PSI have failed to convincingly demonstrate any of these benefits clinically. The influence of guide design on the accuracy of placement of PSI has received no attention within the literature.

Our experience has suggested that surgeons gain greater benefit from PSI when undertaking procedures they are less familiar with. Lateral unicompartmental knee replacement (UKR) is relatively infrequently performed and may be an example of an operation for which PSI would be of benefit. We aimed to investigate the impact on accuracy of PSI with respect to the area of contact, the nature of the contact (smooth or studded guide surfaces) and the effect of increasing the number of contact points in different planes.

Method

A standard anatomy tibial Sawbone was selected for use in the study and a computed tomography scan obtained to facilitate the production of PSI. Nylon PSI guides were printed on the basis of a lateral UKR plan devised by an orthopaedic surgeon. A control PSI guide with similar dimensions to the cutting block of the Oxford Phase 3 UKR tibial guide was produced, contoured to the anterior tibial surface with multiple studs on the tibial contact surface. Variants of this guide were designed to assess the impact of design features on accuracy. These were: a studded guide with a 40% reduction in tibial contact area, a non-studded version of the control guide, the control guide with a shim to provide articular contact, a guide with an extension to allow distal referencing at the ankle and a guide with a distal extension and an articular shim. All guides were designed with an appendage that facilitated direct attachment to a navigation machine (figure 1). 36 volunteers were asked to place each guide on the tibia with reference to a 3D model of the operative plan. The order of placement was varied using a counterbalanced latin square design to limit the impact of the learning effect. The navigation machine recorded deviations from the plan in respect of proximal-distal and medial-lateral translations as well as rotation around all three axes. Statistical analysis was performed on the compound translational and rotational errors for each guide using ANOVA with Bonferroni correction with statistical significance at p<0.05.

Introduction

Wear and corrosion between head and stem tapers of modular hip implants have recently been related to clinical failures, possibly due to high friction moments in poorly lubricated joints [1–2]. In-vivo measurements have revealed reversing joint friction moments in the hip during a gait cycle [3], which may foster relative motion between the modular components. Blood, soft tissue or bone debris at the taper interface during assembly can lead to decreased stability or increased stress concentrations due to non-uniform loading [4]. The purpose of this study is to investigate the influence of taper contamination and the assembly force on the seating characteristic of the head on the stem incorporating realistic reversing joint friction moments.

Methods

Cobalt chrome heads (M-SPEC, 36mm, +1.5mm; n=5) were assembled on titanium femoral stems (Corail 12/14, both components Depuy Synthes; n=5) by quasistatic axial push-on forces (F=0.5kN, 1kN, 2kN). Heads were modified by milling a flat plane, to which the joint load was applied alternately to point A and point B for 20 cycles to provide reversing moments (heel-strike FA=1971N, MA=5.4Nm; toe-off FB=807N, MB=4.6Nm; Fig. 1). All 6 degrees of freedom of relative displacement between head and stem were determined in the unloaded state and after each loading cycle. A coordinate measurement machine (accuracy ±2µm) was used to determine the components positions. Pull-off forces were measured after the last loading cycle. Each taper was tested in pristine condition and then contaminated with a bone chip (1.7±0.2mg).

Introduction

The advance of surgical technique and implant design have led to improvement in total hip arthroplasty (THA), and short stem THA is now gaining number as a treatment option for younger patients to preserve bone in the proximal femur for a future revision. The SMF stem is shorter stem, and requires a slightly higher neck resection and implanted in slight varus to contact at lateral cortex. Developmental dysplasia of the hip (DDH) is the most common cause to hip osteoarthritis (OA) in Japan, and the morphology of the dysplastic femur is narrow canal and increased anteversion. Thus, the purpose of this study is to evaluate the SMF stem design can fit for Japanese patients, using CT based 3-D template planning.

Methods

We evaluated 30 patients who required THA in our institution. Inclusion criteria are hip OA, but cases with post-trauma, post-osteotomy, and any other hip disease in childhood are excluded. Patients were selected with their femoral anteversion, based on the dispersion of anteversion in dysplastic hip population, which was reported by Noble and collegues in 2003. Preoperative planning with ZedHip software (Lexi, Japan) was performed by established protocol. The center of socket was placed at 15mm proximal from teardrop and medialized to primary acetabulum, with 40° of radiographic inclination and 20° of anteversion. Neck resection of femur was 20mm proximal from the top of smaller trochanter, and stem was placed with lateral fit at distal and medial fit at calcar with appropriate size. Stem offset was selected by leg extension and balanced shenton line. Finally, ROM simulation was performed and the socket anteversion was arranged to achieve the optimal ROM. And then, SMF stem alignment and appropriate fitting was evaluated in Japanese OA cases.

Introduction

In total knee arthroplasty (TKA), the setting position of component and the angle influence surgical results. 3D matching evaluation method using the CT before and after operation was a useful method as a rating system after operation. The anterior femoral cortical line (AFCL) is an anatomical landmark for determining intraoperative femoral component rotation in total knee arthroplasty (Fig.1). Our aim in this study is to evaluate the effectiveness of the JIGEN (Jig Engaged 3D Pre-Operative Planning System for TKA) (LEXI, Japan) operation support system using AFCL.

Patients and methods

We performed TKA used GENUS MB (Adler, Italy) by January, 2015 from October, 2013. As for 5 male knees, 37 woman knees, the operation average age were 68 years old. The operation was based on each insertion parameter of the rod in marrow provided by a preoperative plan by the JIGEN system and at first installed a target device in the femoral front and manufactured a insertion point and inserted a rod in the marrow to plan insertion depth (Figure 1). We performed CT photography of the whole lower limbs after operation like preoperation and femoral component setting was located after operation using evaluation software (LEXI, Japan) and evaluated it.

Purpose

The purpose of this study was to evaluate periprosthetic bone mineral density (BMD) changes around a cementless short tapered-wedge stem and determine correlations between BMD changes and various clinical factors, including daily activity, after total hip arthroplasty (THA) with a short tapered-wedge stem.

Methods

The study included 65 patients (65 joints) who underwent THA with a TriLock stem. At baseline, and 6, 12, and 24 months postoperatively, BMDs of the seven Gruen zones were evaluated using dual-energy X-ray absorptiometry. Correlations were determined between BMD changes and clinical factors, including the Harris hip score, body mass index, University of California at Los Angeles (UCLA) activity rating score, age at surgery, and initial lumbar BMD.

Introduction

Measuring the step off during total knee replacement (TKR) is a newly developed operative strategy (“spacer technique”; Heesterbeek et al, KSSTA 2014;22(3):650–9) to determine the optimal contact point (CP) of the femur with the tibia postoperative and to balance the posterior cruciate ligament (PCL) in cruciate-retaining TKR. Engineers have calculated the ideal step off for every size of the TKR, for which the tibiofemoral contact point in 90° will be at the designed position. With this study we determined the postoperative CP in CR-TKA and investigated whether (adverse) clinical outcome was correlated with the CP.

Methods

23 patients presenting with non-inflammatory osteoarthritis, a good functioning PCL, and indication for surgery with a PCL-retaining TKR were selected. Intraoperative PCL balancing was performed with the spacer technique. At 3 months postoperative, a pair of mediolateral radiographs was made using a set-up used for radiostereometric analysis (RSA). The patient was positioned standing with the operated leg in 90 degrees, 50% weight-bearing, knee flexion on a 30 cm-step. Model-based RSA software (RSAcore) was used to determine the 3D positions of the femur and tibia component, that were exported to custom-written software for determining the CP. The CP was defined as the point with the smallest distance between both the medial and lateral femur condyles and tibia plateau. It is expressed as the ratio of the anterior-posterior CP distance and the maximum anterior-posterior tibia plateau size, with 0 being anterior, 1 being posterior. Patients with reduced flexion capacity at follow-up, leading to manipulation under anaesthesia and/or scopic releases, were categorized as COMP, the other patients as no-COMP. CP was compared between these groups.

Introduction

We report 10-year clinical outcomes of a prospective randomised controlled study on uni-compartmental knee arthroplasty using an active constraint robot.

Measuring the clinical impact of CAOS systems has generally been based around surrogate radiological measures with currently few long-term functional follow-up studies reported. We present 10 year clinical follow up results of robotic vs conventional surgery in UKA.

Material and methods

The initial study took place in 2004 and included 28 patients, 13 in the robotic arm and 15 in the conventional arm. All patients underwent medial compartment UKA using the ‘OXFORD’ mobile bearing knee system. Clinical outcome at 10 years was scored using the WOMAC scoring system.

Introduction

Dislocation continues to be a common complication of total hip arthroplasty (THA) [1]. Although many factors affect the prevalence of dislocation, achieving proper intraoperative soft tissue tension is one of the main surgical goals to reduce this risk. However, a sensor to measure the soft tissue of ball joints i.e. hip and shoulder has not yet been developed. The sensor enables surgeons to adjust the size or position of the implants depending on soft tissue tension. Hence, we have developed a sensor-instrumented modular femoral head for THA to measure soft-tissue tension intraoperatively [2]. This study demonstrates the possibility of a soft tissue tension and joint angle data connection using a wireless system.

Materials and Methods

The sensor-instrumented modular femoral head that we developed was made of epoxy resin with linear strain gauges (BTM-1C, Tokyo Sokki, Japan) inside the head and a triple-axis gyroscope (MPU-6500). Strain outputs and angle data from the gyroscope were transferred to a computer via a 2.4 GHz wireless link (RN42, Bluetooth Module).

Data logging was performed by a custom program using C++ (Microsoft Visual Studio 2012) via both wired and wireless link. The strain gauges were embedded inside the head. For the calibration study, the sensor was fixed in a clamping block of an angle vice to permit changes in the direction of force. The calibration jig with the angle vice was placed on top of a low-friction two-dimensional translation table that eliminated horizontal constraints. A constant vertical force was applied using a vertical die set. The experimental setup is shown in Fig. 1. Instead of a portable battery, a DC electric power supply is used (bottom left). A picture of the Gyroscope and the radio module is inserted (bottom right). The force values and applied angles were changed recording strain gauge and angle outputs.

Objective

In Total Knee Arthroplasty (TKA), it is important to adjust the difference of the flexion-extension gap (gap difference) to get the good range of motion and the sufficient stability. However the effect of the gap adjustment on the post-operative knee flexion angle(KFA) is unknown. We investigated the relationship between the gap difference and the postoperative KFA improvement rate.

Methods

179 knees that underwent LCS RP TKA were investigated more than 6 months after surgery(Feb/2013∼Sep/2014). The patients were 49 men and 130 women, of average age 70.6 years (50∼88) and BMI 26.3 (17.0∼55.2). Among them, 175 knees were knee osteoarthritis and 2 joints were rheumatoid arthritis, 2 joints were avascular necrosis. The extension gap was typically prepared with a measured resection, and a small temporary flexion bone gap was prepared with a 4mm resection of the femoral posterior condyle using the pre-cut method(fig 1). Then we measured the gaps under the installation of the Pre-cut Trial(PT; Kaneyama 2011)by the off-set spacer with 1mm increments in patella reduction position(fig 2,3). The final amount of bone resection was determined by comparison of the measured gaps and gaps required for implantation. We calculated the differences between the final extension gap and the final flexion gap and their relationship with knee flexion angles at 6 months postoperatively were analyzed.

Introduction

It has been postulated that the larger femoral head size may be associated with reduced risk of dislocation after total hip arthroplasty(THA). However, Dislocation after THA has a multifactorial etiology with variables such as femoral head size, type of cup, stem and surgical approach.

Objectives

The objectives of this study is to evaluate the association between femoral head component head size, surgical approach, surgeon's experience and the rate of dislocation after THA.

Introduction

Neck and cup impingement resulted in producing larger amount of wear and risk for dislocation after total hip arthroplasty. DDH had more complex to adjust combined cup and femoral neck anteversion during surgery. Dislocation is the second most prevalent complication in total hip replacement with a 2–4% incidence. These resulted in significant financial burden to health care system. Sixteen million US dollars or more cost had in Japanese health insurance system every year. Purpose of this study was to evaluate neck-cup impingement with neck changeable M/L taper Kinectiv stem for DDH patients.

Materials & Methods

Single surgeon's series were analyzed neck cup impingement of 1152 primary total hip surgeries with DDH. 269 hips in men, surgical approach were 754 mini-one antero-lateral, 284 mini- Watson-Jones, and 114 Hardinge. Acetabular cups were seated 20 degrees anteversion. Kinectiv Stem (Zimmer, Warsaw, IN) was inserted manually with standard technique. Femoral head selection was performed 26mm CoCr basis. 32mm were used for 75 years old or more, and 36mm were 80 years or older. First trial was performed with straight type of neck and 26mm femoral head based on preoperative templating. At neck and head trial to evaluated antero-superior impingement with “flex+add.+IR” and postero-inferior impingement with “ext.+add.+ER”. If the neck and cup impingement occurred even if no dislocation, necks were replaced counter version or larger offset.

Introduction

Outpatient total joint arthroplasty (TJA) is emerging as a viable alternative to the historically accepted hospital-based inpatient TJA in the United States. Several studies have focused on the financial advantages of outpatient TJA, however little research has discussed patient reported outcome measures (PROM) and the overall patient experience. The purpose of this study is to compare PROM data in patients undergoing outpatient vs. inpatient total knee arthroplasty (TKA) performed in the first year of a newly opened outpatient facility.

Methods

An internal quality metric database analysis was performed on patients undergoing TKA between 2/14/14 and 5/1/2015. Outpatient TKA was performed at an ambulatory surgery center. Three-hundred and forty-three TKA patients (both inpatient and outpatient) between the ages of 37–65 years old were included. The Oxford Hip, VAS Pain, and Treatment Satisfaction Questionnaires were completed pre-operatively, and at 3- and 6-months post-op.

The Treatment Satisfaction Questionnaire asks 8 questions including “how well did the surgery on your joint increase your ability to perform regular activities?” Patients chose from poor, fair, good, very good, and excellent. Chi-squared analyses determined differences in percentages between outpatient and inpatient PROM. Independent samples t-tests determined significant improvements between pre-op and 6 month post-op PROM scores.

Introduction

Outpatient total joint arthroplasty (TJA) is emerging as a viable alternative to the historically accepted hospital based inpatient TJA in the United States. Several studies have focused on the financial advantages of outpatient TJA, however little research has discussed patient reported outcome measures (PROM) and the overall patient experience. This is a retrospective comparison of PROM data in patients undergoing outpatient vs. inpatient total hip arthroplasty (THA).

Methods

An internal quality metric database analysis was performed on patients undergoing THA between 2/14/14 to 5/1/2015. Outpatients underwent THA at a newly opened ambulatory surgery center. Inpatients underwent THA in a hospital setting. Ninety-six outpatients and 152 inpatients between the ages of 29–65 years old were included. The Oxford Hip, VAS Pain, and Treatment Satisfaction Questionnaires were completed pre-operatively, and at 3- and 6-months post-op.

The Treatment Satisfaction Questionnaire asked 8 questions including “how well did the surgery on your joint increase your ability to perform regular activities?” Patients chose from poor, fair, good, very good, and excellent. Chi-squared analyses determined differences in percentages between outpatient and inpatient PROM. Independent samples t-tests determined significant improvements between pre-op and 3 month post-op PROM scores.

Introduction

The metal-on-metal (MoM) total hip prosthesis is widely used. However, the adverse reactions such as pseudotumor around the total hip prosthesis are observed. This is considered the effect of the corrosion of alloy which includes metal ion release and the wear particle generation. As materials for total hip prostheses, cobalt chromium (Co-Cr) alloy is used because of the wear resistance and corrosion resistance. The passive film on the surface of alloy contributes to corrosion resistance. The passive film is removed easily with friction. Therefore, metal ion is released from bare metal. However, this removal of passive film can be restored because of oxidation reaction with neighboring environment. The modular MoM total hip prosthesis such as acetabular component-femoral head or taper junction which connect femoral head and stem have friction interfaces. The friction amplitudes must be different among these interfaces. However, how sliding amplitude affects on removal of a passive film is unclear. The main purpose of this study was to investigate the effect of the sliding amplitude of the reciplocating micromotion on removal and reformation of the passive film of Co-Cr alloy.

Methods

The behavior of the passive film was observed by measuring the electric potential of the alloy. Co-Cr alloy (ASTM F75) pin specimen and common tablet specimen were immersed in simulated body fluid PBS(−) and abraded with friction testing machine. The electronic potential between the pin and the Ag/AgCl reference electrode (RE-1C, ALS, Tokyo, Japan) were measured using a high impedance electrometer (HE-104E, HOKUTO DENKO, Tokyo, Japan). The friction amplitude was chosen from 0.2–2 mm. The reciprocating cycle was 1 Hz. The load of 10 N applied on the pin by a weight.

Purpose

Most of revision TKA needs bone reconstruction. The success of revision TKA depends on how well the bone reconstruction can be done. The method of reconstruction includes bone cementing, metal augmentation, allogenic bone graft, APC and tumor prosthesis, etc.

In moderate to severe bone defect, allograft is needed. However, allogenic bone graft is surgically demanding and needs long operation time, which is very risky to the elderly patients. The authors revised an alternative method of bone defect reconstruction using cementing method with multiple screws augmentation.

Methods

There were 12 cases of patients with large defect which could not be reconstructed with metal augment from April 2012 to April 2014. The authors performed 3 to 5 screws fixation on the defect site. Sclerotic bone is prepared with burring for better cementing. 3 ∼ 5 screws according to the size of defect. The length of screw fixation was determined as deep to the bone until stable fixation just beneath the implant. When drilling for the screw insertion, intramedullary guide is put into the medullary canal so as not to interfere with implant insertion. The defect is filled with cement during prosthesis fixation. Weight bearing was permitted on postoperative 3rd day, as usual manner of primary TKA.

Introduction

In DDH cases often have high anteversion. They also often have high hip center. THA for those cases sometimes requires subtrochanteric derotational/shortening osteotomy. To achieve good results of the surgery, accurate preoperative planning based on biomechanics of the high anteversion cases, method for accurate application of the plan, and stable fixation are very important. At ISTA 2008, we have reported that the location of the anteversion exist several centimeters below the lesser trochanter. Independently from the extent of anteversion, femoral head, grater trochanter, and lesser trochanter are aligned in the same proportion. We have also reported in 2007, in improper high anteversion cases, many cases grow osteophytes posterior side of femoral head to reduce it functionally. In 2014, we reported about development of the stem for subtrochanteric osteotomy. (ModulusR)[Fig.1] In the present study, we established systematic planning way for estimate proper derotation and shortening and apply it for the surgery.

Methods

Leg alignment during walking were well observed. According to the CT, 3D geometry of the femur, anteversion in hip joint and its compensation by the osteophyte, and knee rotation were measured. It was divided into proximal part and distal part at several centimeter below the lesser trochanter. Adequate hip local anteversion was determined by local original anteversion – compensation if IR-ER can be done. Keeping that anteversion for the proximal part, distal part was rotated as knee towards front. Thus derotation angle was decided. Using 3D CAD (Magics®) proper size of Modulus R was selected and overlapping with canal was extracted then its center of gravity was calculated. This level is decided as the height of osteotomy to obtain equal fixation to both proximal and distal part.[Fig.2] If the derotation angle is less than 15 degree, modular neck adjustment was selected first. By trial reduction and motion test, according to the instability osteotomy was performed. In the high hip center cases, original hip center was reconstructed. Shortening length was determined not to make leg elongation more than 3cm. ModulusR were used for the replacement and fixation of the osteotomy.

Background

Infection is one of the most severe comlications of the total arthroplasty. We sometimes encounter cases, which are very hard to finish repeated recurrence. Usage of steroids, immunosuppressants, and biologics would possibly effect to the incidence of the prosthetic infection and to the result of its treatment. Biologics have drastically decreased the number of the total arthoplasic patients, on the other hand, we must be more careful about the infectious conditions. For the infection two stage revision surgery; first removal and antibiotics cement spacer insertion then reimplantation later; is often chosen but sometimes one time antibiotics cement spacer cannot stop the infection and requires multi times spacer insertion. In those cases the dead spaces, poor blood supply and tight skin could be the cause of the recurrence. For these cases we had been performing musclo-cutaneal flap and successfully finish the infection.

Objectives

Our objectives are to review infection cases treated with musclo-cutaneal flap and compare with treatment without it. Methods: Since 2004 to 2013, 6 infection cases were treated. Our standard policy is 2-staged revision. In the first surgery, the prosthesis was removed and cement spacer was inserted. If no evidence of the remained infection was found reimplantation would be done in the second surgery. Otherwise debridement and cement spacer were repeated. In 3 cases, the infection could be finished without musclo-cutaneal flap but in 3 cases musclo-cutaneal flap was finally done then the infection was finished. The clinical courses were reviewed.

Introduction

Many factors can influence post-operative kinematics after total knee arthroplasty (TKA). These factors include intraoperative surgical conditions such as ligament release or quantity of bone resection as well as differences in implant design. Release of the medial collateral ligament (MCL) is commonly performed to allow correction of varus knee. Precise biomechanical knowledge of the individual components of the MCL is critical for proper MCL release during TKA. The purpose of this study was to define the influences of the deep medial collateral ligament (dMCL) and the posterior oblique ligament (POL) on kinematics in TKA.

Materials and Methods

This study used six fresh-frozen cadaveric knees with intact cruciate ligaments. All TKA procedures were performed by the same surgeon using CR-TKA with a CT-free navigation system. Each knee was tested at 0°, 20°, 30°, 60°, and 90° of flexion. One sequential sectioning sequence was performed on each knee, beginning with femoral arthroplasty only (S1), and thereafter sequentially; medial half tibial resection with spacer (S2), ACL cut (S3), tibial arthroplasty (S4), release of the dMCL (S5), and finally, release of the POL (S6). The same examiner applied all external loads of 10 N-m valgus and 5 N-m internal and external rotation torques at each flexion angle and for each cut state. The AP locations of medial and lateral condyles were determined as the lowest point on each femoral condyle. All data were analyzed statistically using paired t-test. A significant difference was determined to be present for P < .05.

Introduction

Resorptive bone remodeling secondary to stress shielding has been a concern associated with cementless total hip arthroplasty (THA). At present, various types of cementless implants are commercially available. The difference in femoral stem design may affect the degree of postoperative stress shielding. In the present study, we aimed to compare the difference in bone mineral density (BMD) change postoperatively in femurs after the use of 1 of the 3 types of cementless stems.

Methods

Ninety hips of 90 patients who underwent primary cementless THA for the treatment of osteoarthritis were included in this study. A fit-and-fill type stem was used for 28 hips, a tapered-rectangular Zweymüller type stem was used for 32 hips, and a tapered-wedge type stem was used for 30 hips. The male/female ratio of the patients was 7/21 in the fit-and-fill type stem group, 6/26 in the tapered-rectangular Zweymüller type stem group, and 6/24 in the tapered-wedge type stem group. The mean age at surgery was 59.9 (39–80) in the fit-and-fill type stem group, 61.7 (48–84) in the tapered-rectangular Zweymüller type stem group and 59.6 (33–89) in the tapered-wedge type stem group. To assess BMD change after THA, we obtained dual-energy X-ray absorptiometry scans preoperatively and at 6, 12, 24, and 36 months postoperatively.

Purpose

Medial tibial condylar fractures (MTCFs) are rare but a serious complication after unicompartmental knee arthroplasty (UKA). The reasons for MTCFs was thought to be associated with the surgical procedures that are the halls for the guide pins, extended cut of the posterior tibial cortex, an incorrect positioning of the tibial keel groove, and an excessive force application when placing the tibial component. However, the relationship between MTCFs and the alignment of the tibial component has not been proven. The purpose of the study was to investigate the effect of the tibial component alignment to the MTCFs using the finite element method (FEM)

Materials and Methods

We used three-dimensional (3D) image model of the tibia (Sawbones: Washington, US) on the FEM analysis software (ANSYS Design Space ver. 12, Tokyo, Japan). We measured the bone stresses in the 3D image model of the tibia at the site of the medial metaphyseal cortex and the anterior/posterior cortex. The tibial component was placed 0°, 3°varus, 3°valgus, 6°varus, and 6° valgus relative to the tibial anatomical axis in the coronal plane (Figure 1). In sagittal plane, tibial component was positioned 7° posterior inclination relative to the tibial anatomical axis. And, making an additional vertical groove at the posterior cortex by the extended sagittal saw cut of 2° and 10° posterior inclination, the impact of posterior cortical bone stress was evaluated (Figure 2). A load of 900 N was applied to the center of the tibial component parallel to the tibial axis, the maximum bone stress was subsequently calculated. Furthermore, to evaluate the stress distribution, we calculated the bone mass of the 3D bone model below the tibia component under the various alignment of the tibial component (Figure 3).

Purpose

To investigate the tibiofemoral rotational profiles during surgery in navigated posterior-stabilized (PS) total knee arthroplasty (TKA) and investigated the effect on postoperative maximum flexion angles.

Materials and Methods

At first, twenty-five consecutive subjects (24 women and 1 man; age: mean, 77 years; range, 58–85 years) with varus osteoarthritis treated with navigated PS TKA (Triathlon, Stryker, Mahwah, NJ) were enrolled in this study. Kinematic parameters, including the tibiofemoral rotational angles from maximum extension to maximum flexion, were recorded thrice before and after PCL resections, and after implantation. The effect of PCL resection and component implantation on tibiofemoral rotational kinematics was statistically evaluated. Then, the effect of tibiofemoral rotational alignment changes on the postoperative maximum angles were retrospectively examined with 96 subjects (84 women, 12 men; average age, 76 years; age range, 56–88 years) who underwent primary TKA.

Introduction

While fixation on the acetabular side in resurfacing implants has been uncemented, the femoral component is usually cemented. The most common causes for early revision in hip resurfacing are femoral head and or neck fractures and aseptic loosening of the femoral component. Later failures appear to be more related to adverse soft-tissue reactions due to metal wear. Little is known about the effect of cementing techniques on the clinical outcome in hip resurfacing, since retrieval analysis of failed hip resurfacing show large variations. Two cementing techniques have dominated. The indirect low viscosity (LV) technique as for the Birmingham Hip resurfacing (BHR) system and the direct high viscosity (HV) technique as for the Articular Surface replacement (ASR) system. The ASR was withdrawn from the market in 2010 due to inferior short and midterm clinical outcome. This study presents an in vitro experiment on the cement mantle parameters and penetration into ASR resurfaced femoral heads comparing both techniques.

Methods

Five sets of paried frozen cadavar femura (3 male, 2 female) were used in the study. The study was approved by ethics committee. Plastic ASR replicas (DePuy, Leeds, UK), femoral head size 47Ø were used. The LV technique was used for the right femora (Group A, fig. 1 and 3) while the HV technigue was used for the left femora (Group B. Fig 2 and 4). The speciments were cut into quadrants. An initiial visual, qualitative evaluation was followed by CT analysis of cement mantle thickness and cement penetration into bone.

Introduction

Peri-articular local anesthetic injections reduce post-operative pain in total knee arthroplasty and assist recovery. It is inconclusive whether intra-operative injection of peri-articular morphine is locally effective. The aim of this study is whether the addition of morphine to peri-articular injections in only unilateral knee improves post-operative pain, range of motion, swelling in patients with simultaneous bilateral total knee arthroplasty.

Materials and Methods

A prospective single-center double-blinded randomized controlled trial was undertaken to assess the local efficacy of adding morphine to intra-operative, peri-articular anesthesia in simultaneous bilateral total knee arthroplasty. Twenty eight patients with 56 TKAs were randomly divided into 2 groups, unilateral TKA with intraoperative peri-articular injection with adding morphine and the other side TKA without adding morphine. The morphine group received an intraoperative, peri-articular injection of local anesthetic (Ropivacaine 150mg), epinephrine (50μg), ketoprofen (25mg) and methylpredonisolone sodium (20mg) plus 0.1mg/kg of morphine. The no-morphine group received the same amount of local anesthetic, epinephrine, ketoprofen and methylpredonisolone sodium without morphine. The operating surgeon, operating staff, patients, physiotherapists, ward nursing staff and data collectors remained blinded for the duration of study. All surgeries were performed by the same operating team. A standard medial parapatellar approach was used in all operations. Post-operative analgesia was standardized to all participants with celecoxib daily for 3 weeks. Primary outcomes included visual analog pain scores (VAS), ROM and swelling of the thigh. Secondary outcomes included WOMAC and adverse outcomes.

Objective

Computed tomography based three-dimensional surgical preoperative planning (3D-planning) has been expanded to achieve more precise placement of knee and hip arthroplasties. However, few reports have addressed the utility of 3D-planning for the total elbow arthroplasty (TEA). The purpose of this study was to assess the reliability and precision of 3D planning in unlinked TEA.

Methods

Between April 2012 and April 2014, 17 joints in 17 patients (male 4, female 13) were included in this study. Sixteen patients were rheumatoid arthritis and one was osteoarthritis and the average age at the time of the procedure was 61 years (range 28–88). Unlinked K-NOW total elbow system (Teijin-Nakashima Medical. Co. Ltd.) was used in all cases and 3D planning was performed by Zed View (Lexi.Co.). After the appropriate size and position of the prosthesis were decided on the 3D images [Figure 1], the position of the bone tunnel made for the insertion of humeral and ulnar stem was recorded on axial, sagittal, and coronal plane (4 point measurements for humerus, and 6 points for ulna, See Figure 2). After the elbow was exposed via a posterior approach, bone resection and reaming was performed according to the 3D planning. The surgeon took an appropriate adjustment to align the prosthesis properly during the surgery. The final position of the stem insertion was recorded immediately prior to set the prostheses. We analyzed the accuracy of stem size prediction, the correlation between preoperative and final measurements, and postoperative complications.

Introduction

Despite the lack of data regarding the diagnostic validity of synovial aspiration in Girdlestone hips a Girdlestone-aspiration is often performed before reimplantation to detect a possible persistence of infection during two staged revision total hip arthroplasty (THA). The aim of this study was to assess the diagnostic performance of the synovial aspiration in Girdlestone hips, without a PMMA-Spacer, for the detection of infection persistence prior to THA reimplantation.

Methods

Seventy four patients undergoing a two staged revision THA surgery between 2006 and 2013 were included in this retrospective cohort study. Both synovial cultures and CRP values were acquired before explantation of the THA and of the Girdlestone hip before reimplantation. An antibiotic holiday of 14 days was observed prior to synovial aspiration.

A PJI was defined according to the following criteria: intraarticular presence of pus or a sinus tract, a periprosthetic membrane indicative of infection in the histological analysis, or a positive microbiological isolation in a minimum of two samples.

INTRODUCTION

The efficacy of tranexamic acid (TXA) to reduce blood loss in various surgical procedures has been proven. However, there is little data about the effect of TXA on blood loss, rate of blood transfusion and thromboembolic events during periacetabular osteotomy (PAO). The reduction of blood loss during PAO promotes postoperative mobilization and reduces the risk of complications, associated with blood transfusions. The aim of the following study was to determine, if TXA can reduce both blood loss and the rate of blood transfusions. In addition we analyzed whether TXA was associated with an increased risk of thromboembolic events.

METHODS

A consecutive series of 96 PAO procedures was reviewed to compare the groups immediately prior to and following the routine implementation of TXA. The TXA group received a continuous infusion of TXA with a rate of 10mg/kg/h. The outcome was blood transfusion rate, total blood loss, length of hospital stay, and thromboembolic events.

Introduction

Femoral component design is a key part of hip arthroplasty performance. We have previously reported that a hip resurfacing offered functional improved performance over a long stem. However resurfacing is not popular for many reasons, so there is a growing trend towards shorter femoral stems, which have the added benefit of ease of introduction through less invasive incisions. Concern is also developing about the impact of longer stems on lifetime risk of periprosthetic fracture, which should be reduced by the use of a shorter stem. For these reasons, we wanted to know whether a shorter stem offered any functional improvement over a conventional long stem. We surmised that longer stems in hip implants might stiffen the femoral shaft, altering the mechanical properties.

Materials and Methods

From our database of over 800 patients who have been tested in the lab, we identified 95 patients with a hip replacement performed on only one side, with no other lower limb co-morbidities, and a control group:

All groups were matched for BMI and gender.

Participants were asked to walk on an instrumented treadmill. Initially a 5 minute warm up at 4 km/h, then tests at increasing speed in 0.5 km/h increments. Maximum walking speed was determined by the patients themselves, or when subjects moved from walking to running.

Ground reaction forces (GRF) were measured in 20 second intervals at each speed. Features were calculated based on the mean GRF for each trial, and on symmetry measures such as first peak force (heel strike), second peak force (toe-off), the rate at which the foot was loaded and unloaded, and step length.

Introduction

Total hip replacement is one of the most successful orthopaedic surgeries, not least because of the introduction of modular systems giving surgeons the flexibility to intraoperatively adapt the geometry of the artificial joint to the patient's anatomy. However, taper junctions of modular implants are at risk of fretting-induced postoperative complications such as corrosion, which can lead to adverse tissue reactions. Interface micro-motions are suspected to be a causal factor for mechanical loading-induced corrosion, which can require implant revision.

The aim of this study was to determine the micro-motions at the stem-head taper interface during daily activities and the influence of specific material combinations.

Materials & Methods

The ball heads (ø 32mm, 12/14, size L, CoCr or Al2O3) were quasi-statically assembled to the stems (Ti or CoCr, Metha, Aesculap AG, Germany, v=0.5 kN/s, F=6 kN, n=3 each, 10° adduction/ 9° flexion according to ISO 7206-4) and then loaded sinusoidally using a material testing machine (Mini Bionix II, MTS, USA, Figure 1). The peak forces represented different daily activities [Bergmann, 2010]: walking (2.3 kN), stair climbing (4.3 kN) and stumbling (5.3 kN). 2,000 loading cycles (f=1 Hz) were applied for each load level. Six eddy-current sensors, placed between stem and head, were used to determine the displacement (interface micro-motion and elastic deformation) between head and stem (Figure 1). A finite element model (FEM) based on CAD data was used to determine the elastic deformation of the prostheses for the experimentally tested activities (Abaqus, Simulia, USA). Tie-junctions at all interfaces prevented relative movements of the adjacent surfaces. The resultant translations at the centre of the ball head were determined using a coordinate transformation and a subsequent subtraction of the elastic deformation.

INTRODUCTION

Peri-prosthetic fungal infection is generally considered more difficult to cure than a bacterial infection. Two-stage exchange is considered the gold standard of surgical treatment. A recent study, however, reported a favorable outcome after one stage exchange in selected cases where the fungus was identified prior to surgery.

The routine one stage exchange policy for bacterial peri-prosthetic infection involves the risk of identifying a fungal infection mimicking bacterial infection solely on intraoperative samples, i.e. after reimplantation, realizing actually a one stage exchange for fungal infection without pre-operative identification of the responsible fungus, which is considered to have a poor prognosis. We report two such cases of prosthetic hip and knee fungal infection. Despite this negative characteristic, no recurrence of the fungal infection was observed.

CASE N°1: A 78 year old patient was referred for loosening of a chronically infected total hip arthroplasty (Staphylococcus aureus and Streptococcus dysgalactiae). One stage exchange was performed. Intraoperative bacterial cultures remained sterile. Two fungal cultures were positive for Candida albicans. Antifungal treatment was initiated for three months. No infection recurrence was observed at three year follow up.

CASE N° 2: A 53-year-old patient was referred for loosening of a chronically infected total knee prosthesis (Staphylococcus aureus methicillin susceptible, Klebsiella pneumoniae and Staphylococcus epidermidis). One stage exchange was performed. Intraoperative bacterial cultures remained sterile. Five fungal cultures were positive for Candida albicans. Antifungal treatment was initiated for three months. No infection recurrence was observed at two-year follow-up.

DISCUSSION

This experience suggests that eradication of fungal infection of a total hip or knee arthroplasty may be possible after one stage exchange even in cases where the diagnosis of fungal infection was not known before surgery, when the fungus was not identified and its antifungal susceptibility has not been evaluated before surgery. It is however not possible to propose this strategy as a routine procedure.

INTRODUCTION

One of the main goals of total knee arthroplasty (TKA) is to restore an adequate range of motion. The posterior femoral offset (PFO) may have a significant influence on the final flexion angle after TKA. The purpose of the present study was to compare the conventional, radiologic measurement of the PFO before and after TKA to the intra-operative, navigated measurement of the antero-posterior femoral dimension before and after TKA implantation.

MATERIAL

100 consecutive cases referred for end-stage knee osteo-arthritis have been included. Inclusion criteria were the availability of pre-TKA and post-TKA lateral X-rays and a navigated TKA implantation. There was no exclusion criterion.

INTRODUCTION

The diagnosis of peri-prosthetic infection may be difficult. But this diagnosis can guide antibiotic prophylaxis and implementation of intraoperative bacteriological samples. The hypothesis of this study was that a composite score using clinical, radiological and biological data could be used for positive and negative diagnostic of infection before reoperation on prosthetic hip or knee.

MATERIAL

200 reoperations on hip and knee arthroplasty for any cause were analyzed retrospectively. 100 cases concerned infected cases, while the diagnosis of infection was excluded in the other 100 cases.

INTRODUCTION

Measurement of range of motion is a critical item of any knee scoring system. Conventional measurements used in the clinical settings are not as precise as required. Smartphone technology using either inclinometer application or photographic technology may be more precise with virtually no additional cost when compared to more sophisticated techniques such as gait analysis or image analysis. No comparative analysis between these two techniques has been previously performed. The goal of the study was to compare these two technologies to the navigated measurement considered as the gold standard.

MATERIAL

Ten patients were consecutively included. Inclusion criterion was implantation of a TKA with a navigation system.

INTRODUCTION

The efficacy and safety of the tourniquet are discussed, in particular with regard to the blood saving and tissue damage induced by ischemia. The quality of exsanguination and tissue necrosis in the compression zone are significant prognostic factors. The objective of this study was to evaluate the efficacy and safety of a new tourniquet system combining efficient and controlled exsanguination (figure 1) and ischemia maintained by pressure on a minimal surface (figure 2). The hypothesis tested was that the new system allowed tourniquet to reduce blood loss compared to conventional withers without increasing the risk of complications.

MATERIAL

Two groups of 30 patients undergoing total knee arthroplasty (TKA) were compared. There were 39 women and 21 men with a mean age of 67 years and a mean BMI of 34. The study group was operated with the innovative tourniquet and followed prospectively. The control group was operated with the traditional tourniquet and analyzed retrospectively.

INTRODUCTION

Total knee arthroplasty (TKA) is an effective technique to treat end-stage osteoarthritis of the knee. One important goal of the procedure is to restore physiological knee kinematics. However, fluoroscopy studies have consistently shown abnormal knee kinematics after TKA, which may lead to suboptimal clinical outcomes. Posterior slope of the tibial component may significantly impact the knee kinematics after TKA. There is currently no consensus about the most appropriate slope. The goal of the present study was to analyze the impact of different prosthetic slopes on the kinematics of a PCL-preserving TKA. The tested hypothesis was that the knee kinematics will be different for all tested tibial slopes.

MATERIAL

PCL-retaining TKAs (Optetrak Logic CR, Exactech, Gainesville, FL) were performed by fellowship trained orthopedic surgeons on six fresh frozen cadaver with healthy knees and intact PCL. The TKA was implanted using a computer-assisted surgical navigation system (ExactechGPS®, Blue-Ortho, Grenoble, FR). The implanted tibial baseplate was specially designed (figure 1) to allow modifying the posterior slope without repeatedly removing/assembling the tibial insert with varying posterior slopes, avoiding potential damages to the soft-tissue envelope.

Introduction

Opening wedge high tibial osteotomy is an attractive surgical option for physically active patients with early osteoarthritis and varus malalignment. Unfortunately use of this surgical technique is frequently accompanied by an unintended increase in the posterior tibial slope, resulting in anterior tibial translation, and consequent altered knee kinematics and cartilage loading(1).

To address this unintended consequence, it has been recommended that the relative opening of the anteromedial and posterolateral corners of the osteotomy are calculated pre-operatively using trigonometry (1). This calculation assumes that the saw-cut is made parallel to the native posterior slope; yet given the current reliance on 2D images and the ‘surgeon's eye’ to guide the saw-cut, this assumption is questionable.

The aim of this study was to explore how accurately the native posterior tibial slope is reproduced with a traditional freehand osteotomy saw-cut, and whether novel 3D printed patient-specific guides improve this accuracy.

Methods

26 fourth year medical students with no prior experience of performing an osteotomy were asked to perform two osteotomy saw-cuts in foam cortical shell tibiae; one freehand, and one with a 3D printed surgical guide (Embody, London) that was designed using a CT scan of the bone model. The students were instructed to aim for parallelity with a hinge pin which had been inserted (with the use of a highly conforming 3D printed guide) parallel to the posterior slope of the native joint.

For the purpose of analysis, the sawbones were consistently orientated along their mechanical and anatomical tibial axes using custom moulded supports. Digital photographs taken in the plane of the osteotomy were analysed with ImageJ software to calculate the angular difference in the sagittal plane between the hinge-pin and saw-cut. Statistical analysis was performed with SPSS v21 (Chicago, Illinois); a paired t-test was used to compare the freehand and patient-specific guide techniques. Statistical significance was set at a p-value <0.05.

Introduction

Positive expectations can increase compliance with treatment and realistic expectations may reduce postoperative dissatisfaction. Recently there are articles regarding expectations of patients from their TKA in western literature and only few articles based on Korean populations which don't encompass the whole spectrum of expectations in Korean patients. In all those articles based on pre-operative expectation, results were applied to whole expectation category uniformly not differentially. We aimed to document the pre-operative expectations in Korean patients undergoing total knee replacement using an established survey form and to determine whether expectations were influenced by socio-demographic factors and socio-demographic factors influences expectation items in particular category uniformly or differentially.

Methods

Expectations regarding 19 items in the Knee Replacement Expectation Survey form were investigated in 228 patients scheduled for total knee replacement. The levels and distribution patterns of individual and summated expectation of five expectation categories; relief from pain, baseline activity, high flexion activity, social activity and psychological wellbeing, constructed from the 19 items were assessed. Univariate analyses and Binary logistic regression were performed and analyzed to examine the association of expectations with the socio-demographic factors.

Introduction

Unicompartmental knee arthroplasty (UKA) is becoming an increasingly popular option in single compartment osteoarthritis. As a result, diverse re-operations including revisions to total knee arthroplasty (TKA) has also increase. The objective of this study is to investigate the distribution of causes of re-operations after UKA and to analyze the types of re-operations.

Method

We retrospectively reviewed 691 UKAs performed on 595 patients between January 2003 and December 2011. Except in one case, all UKAs were performed for medial compartment osteoarthritis of the knee. The UKAs were performed in 487 (81.8%) women and 108 (18.2%) men. The mean age at the time of UKA was 61.5 years (47 to 88 years). Mobile-bearing designs were implanted in 627 (90.7%) knees (626- Oxford knee and 1- Scorpio knee) and fixed designs were implanted in 64 (9.3%) knees (42- Tornier and 18- Zimmer). The mean interval between UKA and second operation was 15.4 months (10 days to 10 years) and between second and third operation was 7.7 months (5 weeks to 17 months). In the re-operation group, there were 50 knees (48 patients) with 38 female and 10 male patients.

Introduction

Recent advances in nano-surface modification technologies are improving osseointegration response between implant materials and surrounding tissue. Living cells have been shown to sense and respond to cues on the nanoscale which in turn direct stem cell differentiation. One commercially practical surface treatment technique of particular promise is the modification of titanium implant surfaces via electrochemical anodization to form arrays of vertically aligned, laterally spaced titanium oxide (TiO2) nanotubes on areas of implants where enhanced implant–to-bone fixation is desired. Foundational work has demonstrated that the TiO2 nanotube surface architecture significantly accelerates osteoblast cell growth, improves bone-forming functionality, and even directs mesenchymal stem cell fate. The initial in vitro osteoblast cell response to such TiO2 nanotube surface treatments and corresponding in vivo rabbit tissue response are evaluated.

Methods

Arrays of 30, 50, 70, 100nm diameter TiO2 nanotubes formed onto titanium surfaces were compared to grit blasted titanium controls in vitro (Figure 1). SEM micrographs of bovine cartilage chondrocytes (BCCs) on the nanotube surfaces were evaluated after 2 hours, 24 hours, and 5 days of culture. Additionally 20 samples each of various nanotube diameters and the non-nanotube treated titanium controls were evaluated after exposure to human mesenchymal stem cell (hMSC) after 2 hours and 24 hours.

The left tibia and right tibia of four rabbits were implanted with disk shaped titanium implants (5.0 mm dia. × 1.5 mm) with and without TiO2 nanotubes. The front side of each implant faced the rabbit tibia bone and the back side of the implant had screw holes for post-in vivo tensile testing. After 4 weeks, the bones with implants were retrieved for mechanical testing and histology analysis.

Comparative osteogenic behavior on metal oxide nanotube surfaces applied to other implant material surface chemistries including ZrO2, Ta, and Ta2O5 were also evaluated along with TiO2 nanotubes formed on a thin films of titanium on the surface of zirconia and CoCr alloy orthopedic implants.

Introduction

Failure of the polyethylene glenoid component is the most common complication of Total Shoulder Arthroplasty (TSA) and accounts for a majority of the unsatisfactory results after this procedure. Nowadays, most of the shoulder prostheses consist of metal on polyethylene bearing components. Repetitive contact between the metal ball and the polyethylene socket produces progressive abrasion of the implant if the moving part is made of polyethylene. Its debris may then lead to an active osteolysis and implant loosening. Failure of the glenoid component is often manifested clinically by pain, loss of function, and the presence of a clunking noise and leads to revision surgery.

The use of ceramic balls aims at the reduction of this phenomenon. In many studies regarding knee and hip replacement it has been shown that the use of ceramic on polyethylene (CoP) is more beneficial in terms of polyethylene wear and failure, when compared to metal on polyethylene (MoP).

Since a human shoulder is very different from a hip and a knee, it is not a self-centering, neither congruent joint. And its stability is provided by healthy muscles of the rotator cuff. We decided to compare CoP against MoP in semi- force controlled test setup. Where, for a given governing angular motion the translational motion was a function of contact (frictional) forces between the tested couple (humeral head and PE).

This is to our knowledge the first study to address in direct comparison wear in TSA in semi force controlled test setup.

Materials and methods

Up today, there is no test standard for wear testing of TSA. A customised joint simulator was used to create worst-case scenario motion allowing for simulation of the muscles in two perpendicular axes: inferior – superior (I-S) and anterior – posterior (A-P). Were a governing angular motion (GAM) was the abduction – adduction (±30°) in I-S. A system of springs was created so that the I-S translation and the A-P rotation were a result of the GAM. The stiffens of the springs was tuned based on the MoP pair initial kinematic (1000 cycles) to result in: about 2mm I-S translation, and about ±10° A-P rotation.

All samples were tested at the same test station in order to obtain maximal repeatability. Axial load was in range of 100N to 750 N.

Three articulating couples for each material were tested for total of 2M cycles. Standard midterm gravimetric measurements were conducted at each 0.5 M cycles.

Objectives

Proximal tibial fracture is one of the most common postoperative complications of unilateral knee arthroplasty (UKA). The objective of the present study is to investigate the risk factors of these fractures, occurred after UKA in our facility.

Method

We performed 314 UKAs between May 2006 and December 2013. All cases were done using Oxford UKA. Proximal tibial fractures were observed in 5 cases. 4 cases were female and 1 case was male, and the age at the operation ranged from 73 to 90. All cases were osteoarthritis. 4 cases were diagnosed as stress fracture with minimum displacement, and 1 case was fracture with displacement. We investigated the risk factors of the tibial fracture among those 5 cases. Low bone mineral density(BMD), the presence of medial tibial cortex pinhole, excessive vertical cut, and adjacence of keel and posterior tibia cortex were estimated as risk factors.

Introduction

We report a case which total knee arthroplasty (TKA) was able to be performed on schedule for the patient with occult fracture of proximal tibia which seemed to have occurred three months prior to the surgery, and has healed in short period of time by the use of Teriparatide.

Case report

The patient is 84-year-old female, having right knee pain for past 7 years. Her knee pain increased by passive extension maneuver that was done by a bonesetter 3 months prior to the surgery. On her initial visit, the X-ray finding was severe medial osteoarthritis, and femorotibial angle (FTA) in the upright film was 197°, but there was no other disorder including fracture. Since the bone mineral density (BMD) of affected femoral neck was 62%YAM, and affected lateral femoral condyle as well as lateral tibial condyle seemed very porotic, we started using daily 20μg Teriparatide injection from 3 months prior to the surgery. Proximal tibial fracture was presented in the X-ray taken on the day before surgery, but since adequate bone union has already been formed, surgery was performed on schedule. Tibial implant with long stem was used for just to be certain. Thanks to the Teriparatide, the condition of cancellous bone in cut surface was excellent, and reaming of the tibia through fracture area felt very solid.

Introduction

The French paradox regarding cemented femoral components has not been resolved, so we compared the mechanical behavior of a French stem, the CMK stem (Biomet, Warsaw, IN, USA), with a collarless, polished, tapered stem (CPT, Zimmer, Warsaw, IN, USA) using an original biomechanical instrument.

Materials and Methods

Two size-3 CPT stems and two size-302 CMK stems stems were fixed with bone cement into a composite femur soaked in vegetable oil to simulate wet condition. The composite femur was attached to a biomechanical testing instrument after stem implantation, and a 1-Hz dynamic sine wave load (3000 N) was applied to the stems for a total of 1 million cycles. An 8-hour unload period was set after every 16 hours of load. Femur temperature was maintained at 37°C during testing. The femoral canal was prepared for the CPT stems by standard rasping; for the CMK stems, however, the French method was used, in which cancellous bone was removed with a reamer. One CMK stem (CMK-1) was inserted into a femur without collar contact (>2 mm above the calcar), and the other (CMK-2) was inserted into a femur with collar contact. Stem subsidence was measured at the stem shoulder. Compressive force and horizontal cement movement were measured via rods set at the cement–bone interface on the medial, lateral, anterior, and posterior sides of the proximal and distal portions of the composite femurs.

Introduction

The conventional bone resection technique in TKA is recognized as less accurate than computer-assisted surgery (CAS) and patient-matched instrumentation (PMI). However, these systems are not available to all surgeons performing TKAs. Furthermore, it was recently reported that PMI accuracy is not always better than that of the conventional bone resection technique. As such, most surgeons use the conventional technique for distal femur and proximal tibia resection, and efforts to improve bone resection accuracy with conventional technique are necessary. Here, we examined intraoperative X-rays after bone resection of the distal femur and proximal tibia with conventional bone resection technique. If the cutting angle was not good and the difference from preoperative planning was over 3º, we considered re-cutting the bone to correct the angle.

Methods

We investigated 117 knees in this study. The cutting angle of the distal femur was preoperatively determined by whole-length femoral X-ray. The conventional technique with an intramedullary guide system was used for distal femoral perpendicular resection to the mechanical axis. Proximal tibial cutting was performed perpendicular to the tibial shaft with an extramedullary guide system. The cutting angles of the distal femur and proximal tibia were estimated by intraoperative X-ray with the lower limb in extension position. When the cutting angle was over 3º different from the preoperatively planned angle, re-cutting of distal femur or proximal tibia was considered.

Introduction

This study reports outcomes of 35 revisions of a recalled metal-on-metal (MOM) monoblock prosthesis performed by a single surgeon.

Methods

We prospectively collected data on all patients who underwent revision of a recalled metal-on-metal monoblock prosthesis between 2010 and 2015. Average follow-up was 2.5 years post-revision and 6.9 years post-primary procedure. We evaluated the cohort for age, BMI, gender, existence of medical comorbidities, and post-op complications. We compared pre and post-revision cup abduction angles, anteversion angles, combined angles, cup sizes, and Harris Hip Scores. Cobalt and chromium levels were followed throughout the study period for each patient.

Introduction

Even a number of studies have reported clinical outcomes after revision total knee arthroplasty (revision TKA), little information is still available on whether outcomes of patients undergoing a revision TKA as a second stage procedure because of infected TKA are poorer than those of the patients undergoing a single-stage revision TKA because of non-infectious causes. In addition, use of various revision prostheses in most previous studies may limit solid interpretation of the outcomes after revision TKA. This study sought to determine whether outcomes in patients undergoing revision TKA due to infected TKA would be different from those in patients undergoing revision TKA due to non-infectious causes.

Materials and Methods

We assessed 71 cases undergoing revision TKAs with use of a same revision system (Scorpio TS®, Stryker, Mahwah, NJ) from October 1999 to February 2012. All patients followed more than two years and mean follow-up period was 67 months (range: 24 – 168 months). Of them, thirty five patients underwent revisions due to infected TKA (group for infected TKA) while 36 patients due to non-infectious causes including loosening, wear, and/or instability (group for non-infected TKA). All patients in the group for infected TKA underwent two-stage revision surgeries while all patients in the group for non-infected TKA single stage revision surgeries. Comparative variables between two groups were preoperative range of motion (ROM) and American knee society (AKS) scores, postoperative ROM and AKS scores assessed at latest follow-up, amount of bone loss and requirement of stem assessed during the surgeries, and survival rate.

Introduction

Total knee arthroplasty (TKA) is a proven treatment method for advanced knee arthritis in terms of pain relief, function restoration, and quality-of-life improvement. The TKA use has increased significantly over the past decade and the growing rate is more prominent in Asian countries. Thus, the revision TKA may also increase in recent days, which represents a burden to the national health care system. To the best of our knowledge, little information is currently available regarding the incidence and related factors of revision TKA in Asian countries on the basis of nationwide database. This study sought to find the incidence of revision TKA and related factors in South Korea using national database from 2007 to 2012.

Material and Method

Data collected by the Health Insurance Review Agency of Korea, from 260,068 TKA patients between 2007 and 2012, were used to estimate the incidence of revision TKA according to age group, gender and hospital TKA and manufacturer prosthesis volume (i.e., the number of TKA procedures carried out at a given hospital, and the number of procedures performed using a given manufacturer's prosthesis, respectively). Age group and hospital and manufacturer volumes were categorized into three groups and TKA incidence rates were computed for groups stratified according to age, gender and hospital and manufacturer volumes.

Purpose

Topical application of tranexamic acid (TXA) to bleeding wound surfaces reduces blood loss in patients undergoing some major surgeries, without systemic complications. The objective of this study was to determine if TXA applied topically reduced postoperative bleeding and transfusion rates after primary total hip arthroplasty (THA) and primary bipolar hemiarthroplasty (BA).

Methods

We retrospectively compared 77 patients undergoing hip arthroplasty surgery in which tranexamic acid was routinely used, to a group of 70 patients from a similar time frame prior to the introduction of tranexamic acid use. In the former group 40 patients had THA and 37 patients BA; in the latter group 35 patients underwent THA and 35 patients BA. In both THA and BA, the joint was bathed in TXA solution (at a concentration of 3.0 g TXA per 100 mL saline) at three points during the procedure. The primary outcome was blood loss calculated from the difference between the preoperative hemoglobin level and the corresponding lowest postoperative value or hemoglobin level prior to transfusion.

Introduction

Revision total knee arthroplasy (TKA) has been often used with a metal block augmentation for patients with poor bone quality. However, bone resorption beneath metal block augmentation has been still reported and little information about the reasons of the occurrence of bone resorption is available. The aim of the current study is to identify a possibility of the potential occurrence of bone resorption beneath metal block augmentation, through evaluation of strain distribution beneath metal block augmentation in revision TKA with metal block augmentation, during high deep flexion.

Materials and Method

LOSPA, revision TKA with a metal block augmentation (Baseplate size #5, Spacer size #5, Stem size Φ9, L30, Augment #5 T5) was considered in this study. For the test, the tibia component of LOSPA was implanted to the tibia sawbone (left, #3401, Sawbones EuropeAB, Malmö, Sweden), which was corresponded to a traditional TKR surgical guideline. The femoral component of LOSPA was mounted to a customized jig attached to the Instron 8872 (Instron, Norwood, MA, USA), which was designed specially to represent the angles ranged from 0° to 140° with consideration of a rollback of knee joint (Figure. 1). Here, a compressive load of 1,600N (10N/s) was applied for each angle. Strain distribution was then measured from rossete strain gauge (Half Bridge type, CAS, Seoul, Korea) together (Figure 1).

Purpose

Investigating the effects of femoral stem length on hip and knee muscle strength.

Methods

The study included 20 patients having undergone total knee prostheses (TKP) due to coxarthrosis and 10 healthy subjects. Of the 20 patients, 10 underwent conventional TKP and 10 had Thrust Plate Prothesis (TPP). For the assessment of the patients’ muscle strength of operated and non-operated hips (Gl. medius and Gl. Maximus) and knees (Quadriceps Femoris-QF), the Hand-Held Dynamometer (HHD) was used.

BACKGROUND

Abnormal glenoid version positioning has been recognized as a cause of glenoid component failure caused by the rocking horse phenomenon. In contrast, the importance of the glenoid inclination has not been investigated.

MATERIALS AND METHODS

The computed tomography scans of 152 healthy shoulders were evaluated. A virtual glenoid component was positioned in 2 different planes: the maximum circular plane (MCP) and the inferior circle plane (ICP). The MCP was defined by the best fitting circle of the most superior point of the glenoid and 2 points at the lower glenoid rim. The ICP was defined by the best fitting circle on the rim of the inferior quadrants. The inclination of both planes was measured as the intersection with the scapular plane. We defined the force vector of the rotator force couple and calculated the magnitude of the shear force vector on a virtual glenoid component in both planes during glenohumeral abduction.

Introduction

In revision surgery, detection of periprosthetic joint infection is of prime importance. Valuable preoperative and intraoperative diagnostic tests and tools are necessary. The classical standard procedures are puncture and bacteriology examination, frozen section intraoperative and powerfield micro analysis.

Since autumn 2014 a new device for detection of periprosthetic joint infection is available, named Synovasure. It is a fast test for the detection of Alpha defensing, which plays a major role in the antimicrobial defence and only occurs in inflammatory processes.

„The alpha-defensin test is an immunoassay that measures the concentration of the alpha-defensin peptide in human synovialfluid. A-Defensin is an antimicrobial peptide that is secreted into the synovial fluid by human cells in response to pathogenic presence” (Deirmengian C et al., CORR 2014).

Summarized, the evidence of Alpha defensin indicates infection. It is produced by CD Diagnostics (Wynnewood, PA, USA) and merchandised by Zimmer (Warsaw, IL, USA).

We are using Synovasure in daily routine at our department since September 2014. The aim of this conducted study is to present our first clinical experience and to report our results of the first 54 cases.

Material and Methods

At our department Synovasure is standardly used in hip and knee revision surgery.

Additionally an intraoperative frozen section and a standard bacteriology were performed. The explanted endprosthesis were sent to examination by sonification in order to gain culture of the sonification fluid and were further examined by Multiplex PCR. A pathologist with more than 15 years of experience conducted the frozen section. The results of Synovasure were matched with all above examinations in order to describe specifity and sensitivity of it.

INTRODUCTION

Total knee replacement is mostly done with alignment rods in order to achieve a proper Varus / Valgus alignement. Other techniques are computer assisted navigation or MRI based preoperative planning. iASSIST™ is a computer assisted stereotaxic surgical instrument system to assist the surgeon in the positioning of the orthopaedic implant system components intra-operatively.

It is imageless and the communication between the PC and the “Pod's” does not require any direct camera view, it is a bluethooth comunication system. This study presents preliminary results utilizing iASSIST™.

The aim of this study was to test and compare radiographic alignment, functional outcomes, and perioperative morbidity of the iASSIST™ Knee system versus conventional total knee arthroplasty.

METHODS

In a prospective randomized trial we investigated 60 patients with osteoarthritis of the knee joint. Each surgical procedure was conducted by highly experienced surgeons. In both groups the implant Legacy LPS-Flex Fixed Bearing Knee was used (Zimmer®, Warsaw, Indiana). The groups were equally divided and randomized by hazard. For clinical evaluation, the Short Form-36 and Knee Society Score were obtained. For the radiological assessment mediCAD® Classic, a digital measurement system, was used. The aim of the study was the comparison of results after 3 months.

Introduction

Computer Tomography (CT) imaging has been limited to beam hardening artefacts until now. Literature has failed to describe sensitivity and specifity for loosening of endoprothesis in CTs, as metal artefacts have always influenced the diagnostic value of CTs.

In recent years a new technology has been developed, the Dual Energy CT. Dual Energy CT scanners simultaneously scan with two tubes at different energy levels, most commonly 100kVp and 140kVp. Furthermore pictures gained from Dual Energy CTs are post-processed with monoenergetic reconstruction, which increases picture quality while further reducing metal artefacts.

This promising technology has increased the diagnostic value preventing more radiation for the patients, for example in detection of kidney stones or to map lung perfusion. In the musculoskeletal imaging it has not been established yet and further clinical investigations are necessary.

Thus the aim of this study is to describe sensitivity and sensibility for endoprothesis loosening of this novel technology.

Material and Methods

53 prospective patients (31 total hip- and 22 total knee-arthoplasties) who were planned for revision surgery underwent preoperative Dual Energy CT examination. All scans were performed with a second-generation, dual-energy multi-detector CT scanner. And all pictures were post-processed with monoenergetic reconstruction.

Radiologists were blinded for patient´s history. Senior consultants, who are specialized in arthroplasty of the hip and the knee, performed surgery. Intraoperative information was used as gold standard.

Introduction

Many factors can influence post-operative kinematics after total knee arthroplasty (TKA). These factors include intraoperative surgical conditions such as ligament release or quantity of bone resection as well as differences in implant design. Release of the medial collateral ligament (MCL) is commonly performed to allow correction of varus knee. Precise biomechanical knowledge of the individual components of the MCL is critical for proper MCL release during TKA. The purpose of this study was to define the influences of the deep medial collateral ligament (dMCL) and the posterior oblique ligament (POL) on valgus and rotatory stability in TKA.

Materials and Methods

This study used six fresh-frozen cadaveric knees with intact cruciate ligaments. All TKA procedures were performed by the same surgeon using CR-TKA with a CT-free navigation system. Each knee was tested at 0°, 20°, 30°, 60°, and 90° of flexion. One sequential sectioning sequence was performed on each knee, beginning with an intact knee (S0), and thereafter femoral arthroplasty only (S1), tibial arthroplasty (S2), release of the dMCL (S3), and finally, release of the POL (S4). The same examiner applied all external load of 10 N-m valgus and a 5 N-m internal and external rotation torque at each flexion angle for the each cutting state. All data were analyzed statistically using one-way ANOVA and we investigated the correlation between the medial gap and the rotation angle. A significant difference was determined to be present for P < .05.

Aim

The aim of this study is to evaluate the effect of three-dimensional (3D) simulation with 3D planning software ZedKnee® (ZK) in total knee arthroplasty (TKA).

Materials and methods

The participants in this study were all TKA patients whose operations were simulated by using ZK. The alignment of all components was evaluated with the ZK valuation software in postoperative computer tomography. Thirty patients (43 knees) met the inclusion criteria. 6 patients were male and 24 patients were female. The mean age of the 30 patients was 72 years old. Diagnoses for surgery were: osteoarthritis- 40 knees, rheumatoid arthritis- 2 knees and osteonecrosis- 1 knee. TKA was performed using the measured resection technique. The distal femur axis where the intramedullary rod would be inserted was drawn manually on the 3D image. Then, the angle between the distal femoral axis and the mechanical axis was measured. The rotational angles of the femoral components were determined from the automatically calculated angle between the posterior condylar axis and the surgical epicondylar axis (SEA) by using ZK. The ZK data used during the operation was the posterior condylar angle, the angle between the distal femoral axis and the mechanical axis and implant size.

Introduction

In the previous study regarding the relationship among maximum hip flexion, the pelvis, and the lumbar vertebrae on the sagittal plane, we have found in X-rays that the lumbo lordotic angle (LLA) and the sacral slope angle (SSA) have a large impact on hip flexion angle. We examined hip flexion angles to the various height of the objects (half round plastic tube) placed under the subject's lower back and compared the passive hip flexion angles in the supine position between younger and middle age groups.

Participants

The participants were 14 healthy volunteers: 7 females with an average age of 17 years (Group 1: G-1), 7 females with an average age of 45 years (Group 2: G-2). The average BMI (Body Mass Index) of volunteers was less than 25, and their Tomas Tests were negative.

Introduction

Deformity after femoral osteotomy varies between patients. Some researchers reported good results when using cemented stems for the hips after femoral osteotomy, but there are many disadvantages that obstruct ideal fixation using cemented stems. Therefore, we developed cementless custom-made stems and inserted those using a computed tomography (CT) –based navigation system

Methods

Eighteen dysplastic hips of 15 patients after intertrochanteric osteotomy were investigated in the present study. Individual computed tomography data were used to manufacture cementless custom-made femoral stems out of Ti-6Al-4V. The proximal 1/3 of each stem was coated using porous coating covered with hydroxyapatite coating. The stems were inserted using a CT-based fluoro navigation system for accuracy of insertion. The average patient age at time of surgery was 66 years, and the average follow-up period was 3.5 years.

Background

Ankle arthroplasty is increasingly used to reduce pain and improve or maintain joint mobility in end-stage ankle arthritis. Both treatments show similar results with regard to functional outcome scores and sport related activities. However, the rates of complications and reoperations were higher after ankle replacement. Particularly for the first implant designs, with more promising results for newer designs.

One of these newer designs is the Mobility Total Ankle System. Short term results in recent literature describe an improvement of functional outcomes; however complication rates vary widely, ranging from 9 to 37% and the 4-year survival rates ranging between 84 and 98 percent. Therefore, the aim of this study was to assess the clinical and radiographic short term results of the Mobility prosthesis.

Methods

Between March 2008 and September 2013, 67 primary total ankle arthroplasties with the Mobility prosthesis were performed, in 64 patients, by one experienced foot and ankle surgeon.

Complications, reoperations, failures and the survival rate were retrospectively examined.

Patient reported outcomes were assessed with the use of the FFI score and visual analogue scale (VAS) for pain. Prosthesis alignment was measured on the first weightbearing radiographs of the ankle according to the procedure described by Rippstein et al.1 (Fig. 1).

Purpose

With growing attention being paid to quality and cost effectiveness in healthcare, outcome evaluations are becoming increasingly important. This determination can be especially difficult in reverse shoulder arthroplasty (RSA) given the complex pathology and extensive disabilities in this patient population. Several different scoring systems have been developed and validated for use in various shoulder pathologies. The purpose of this study was to assess the use three outcome scores in a population of patients undergoing RSA. We aim to demonstrate the validity of three outcome scores in patients undergoing RSA, and to determine if one score or a combination of scores is superior to others.

Methods

Using a database of patients treated with RSA, we assessed preoperative and postoperative Constant Scores, American Shoulder and Elbow Surgeons (ASES) scores, and subjective shoulder values (SSV) in 148 shoulders. The outcomes at each scoring period were described and the scores were compared to one another as well as to active range of motion using linear regression modeling.

Introduction

Accurate acetabular cup orientation could lead to successful surgical results in total hip arthroplasty (THA). We introduce a novel CT-based three-dimensional (3D) planning system, HipCOMPASS (Fg.1) and TARGET (Fig.2), which enable to design suitable alignment not only cup also surgical devices calculatingly, according to each pelvic inclination.

Patients and methods

We performed THA in 13 patients (10 female and 3 men) between September 2014 and April 2014. Average age were 67 years old. THA operation was based on each parameter of the cup and device, providing a preoperative planning by ZedView system. HipCOMPASS and TARGET is linked with ZedView software, which is simultaneously calibrated adjustable parameters on this devices. Cup alignment was assessed by ZedView as well.

Background

In this study, we investigated the long-term clinical results and survivorship of minimally invasive unicompartmental knee arthroplasty (UKA) by collecting cases that have been implanted for >10 years ago.

Methods

Medial UKA on 180 cases in 142 patients was performed over a period of 1 year after the first introduction of minimally invasive UKA from January 2002 to December 2002. Among these, 166 cases in 128 patients who underwent Oxford phase 3 medial UKA using the minimally invasive surgery, with the exclusion of 14 cases including 10 cases of follow-up loss and 4 cases of death, were selected as the subject. The mean age of the patients at the time of surgery was 61 years, and the duration of the follow-up was minimum 10 years. All the preoperative diagnosis was osteoarthritis of the knee joint. Clinical and radiographic assessments were measured by the Knee Society clinical rating system, and the survival analysis was confirmed by the Kaplan–Meier method with 95% confidence interval (CI).

Purpose

To identify the modes of failure after total knee arthroplasty (TKA) in patients ≤ 55 years of age and to compare with those ≥ 56 years of age in patients who underwent revision TKA.

Materials and Methods

We retrospectively reviewed 256 revision TKAs among patients who underwent TKA for knee osteoarthritis between January 1992 and December 2012. The causes of TKA failure were analyzed and compared between those ≤ 55 years of age and those ≥ 56 years of age. The age at the time of primary surgery was ≤ 55 years in 30 patients (31 knees) and ≥ 56 years in 210 patients (225 knees).

Background

Management of the patella with poor bone stock remains a challenge in revision total knee arthroplasty (TKA). The purpose of this study was to evaluate the results of a novel surgical technique in which widely available wires and acrylic bone cement are used in the reconstruction of a deficient patella.

Methods

Twenty-eight patients (30 knees) underwent revision TKA in which a deficient patella was treated with an onlay-type prosthesis and bone-augmenting procedure, using transcortical wiring. The technique was indicated when the thickness of remnant patella was less than 8mm with variable amounts of the peripheral rim. The remaining patellar height ranged from 3.2mm to 7.3mm. Follow-up was available for all patients with a mean of 36.6 months (range, 24 to 55 months).

Introduction

A stem extension improves fixation stability of a tibial component. We need caution not to contact the tibial cortex with an offset adaptor. A symmetric tibial stem design often requires the component's re-positioning with negative effects. Therefore, the objective of this study was to validate clinical efficacy of a tibial baseplate with asymmetric stemmed position (TB-ASP) using aligning outlier rate. We hypothesized that TB-ASP design will be better aligned without unessential offset adaptor than a tibial baseplate with symmetric stemmed position (TB-SSP).

Methods

TB-ASP was designed based on the anthropometric standard model (58 female cadavers, 54.7±11.4 years)(Figure 1.). To validate the stem position, 3D bone models of 20 OA patients (71.8±7.2 years) was reconstructed. All virtual surgery has done by one surgeon with consistent surgical procedure for the analysis criteria.

An analysis of TB-ASP's aligning outlier was proceeded by following steps; 1) aligning tibial baseplate to the line from medial 1/3 tuberosity to the center of PCL, 2) selecting tibial baseplate's size for maximal bone coverage without problematic overhang, 3) trying to displace tibial baseplate and stem extension(120mm long) not to contact tibial cortex. A case invading tibial cortex was considered to be an outlier. The ratio using offset adaptor was compared to those of TB-SSP. Statistical analysis was performed using paired t-test.

Introduction

The acetabular cup should be properly oriented to prevent dislocation and to reduce wear and leg length discrepancy. Despite advances in surgical techniques and instrumentation, achieving proper cup placement in total hip arthroplasty (THA) is challenging with potentially large variations of cup position and limited accuracy. We evaluated whether cup placement on anatomical location ensured original center of rotation (COR) and surgeon's experiences of THA reduced variations in acetabular component positioning.

Methods

We retrospectively reviewed 145 patients (145 hips) of unilateral THAs with normal contralateral structures of acetabulum and femoral head. All surgeries were performed using the modified posterolateral approach that preserves short external rotator muscles. All of the 145 THAs were performed by two surgeons, who were in the same teaching hospital, but had differences in surgical experience and expertise for THA. The patients were divided into two groups based upon surgical experience: (1) the highly experienced surgeon's group: who had previously performed over 1000 THAs (YSK, 101 hips), and (2) the less experienced novice's group: who had performed fewer than 30 THAs (YWL, 44 hips). Real vertical distances, from the COR to the inter-tear drop line, and the real horizontal distances, from the COR to the lateral wall of the tear drop, were measured preoperatively using picture archiving communication system (PACS) based precise method. Postoperative ones were measured and equalized by use of a magnification marker placed on preoperative plain radiographs. And cup inclination was measured directly on the AP radiographs and anteversion was calculated by trigonometric functions. The patient's mean age was 52.1 years (range, 20–86).

Background

Theoretically, improved material properties of new alumina matrix composite (AMC) material, Delta ceramics, are expected to decrease concerns associated with pure alumina ceramics and allow manufacturing thinner liners and consequent larger heads. However, limited short-term clinical results are available and mid-term results of these effects are unclear.

Questions/Purposes

(1) Does AMC material decrease the rate of ceramic fracture and noise, concerns of previous-generation ceramics, following change of material properties? (2) Does the possible use of larger heads consequent to manufacturing thinner liners decrease dislocation rate and affect inguinal pain? (3) Do any other complications associated with the use of AMC ceramics occur?

Introduction

The pathophysiology of osteonecrosis of femoral head (ONFH) is uncertain for most cases with speculation of vascular impairment and changes in cell biology due to multi-factorial etiologies including corticosteroid, alcohol, smoking, trauma, radiation or caisson disease and genetic. Extracorporeal shockwave therapy (ESWT) began with an incidental observation of osteoblastic response pattern during animal studies in the mid-1980 that generated an interest in the application of ESWT to musculoskeletal disorders. The mechanism of shockwave therapy is not fully understood but several reports showed better clinical outcomes and promoted bone remodelling and regeneration effect of the femoral head after ESWT in ONFH. Therefore, we compared the clinical results of the use of extracorporeal shock wave therapy (ESWT) on the patients with ONFH in radiographic staging.

Methods

We evaluated 24 patients with 32 hip joints diagnosed ONFH treated with ESWT from 1993 to 2012. Average follow-up period was 27 months, and patients were average 47.8 aged. Association Research Circulation Osseous (ARCO) staging system was used to grade radiographic stage before treatment. All the patients were divided to two groups; group 1 (ARCO stage I,II), group 2 (ARCO stage III). Comparative analysis was done between two groups with visual analogue scale (VAS) score and Harris hip score (HHS) at pre-treatment, 3, 6, 12 and 24 months after treatments. The failure was defined when radiographic stage was progressed or arthroplasty surgery was needed due to clinical exacerbation.

Introduction

Ultra high molecular weight polyethylene (UHMWPE) has been used successfully as a bearing material in hip, knee, and shoulder joint replacements. However, there are problems to cause a failure in UHMWPE component, which are wear behavior and creep deformation. Continuous bearing motion and dynamic load have occurred to UHMWPE wear debris caused osteolysis in periprosthetic tissue and to plastic deformation of joint component, and subsequent aseptic loosening of components. Therefore, many studies have being carried out in order to reduce wear debris and to improve mechanical strength from UHMWPE, and there is tremendous improvement of mechanical property in UHMWPE from gamma irradiated conventional UHMWPE (GIPE), highly crosslinked PE (XLPE), and XLPE with vitamin E1, 2. Friction has a significant one of the factors effect on the wear and creep deformation. In this study, the short-term frictional behaviors of three typical types of GIPE, remelted XLPE (R-XLPE), and s annealed XLPE (A-XLPE), and XLPE with Vitamin E against Co-Cr alloy were compared under three levels of contact pressures which occured in hip, knee, and shoulder joints.

Methods

Friction tests were conducted with UHMWPE against Co-Cr alloy by using pin-on-disk type triboteter. For test, tribotester performed in a repeat pass rotational slidintg motion with a velocity of 60rpm. Applied contact pressure selected three kinds of levels, 5, 10, and 20MPa which were within the range of maximum contact pressures for total hip, knee, and shoulder joint replacements. To analyze the frictional effect of UHMWPE type, it conducted t-test and p-values less than 0.05 were used to determine the statistically significant difference.

Purpose

To observe the follow-up results of standard cemented bipolar hemiarthroplasty with double loop and tension band wiring technique for treatment of unstable intertrochanteric hip fractures in elderly patients with osteoporosis.

Materials and Methods

From May 2000 to May 2006, 86 cemented bipolar hemiarthroplasties were performed in elderly patients who had unstable intertrochanteric fractures. The mean age at the time of surgery was 82 years old. The average follow-up period were 5.3 years. We evaluated post-operative results after operation by clinical and radiographic methods.

Introduction

Patient matched instrumentation (PMI) have been proposed the accuracy of bone cuts through custom cutting blocks and provide the proper alignment of total knee arthroplasty (TKA). On the other hand, there are some reports that the introduction of PMI for guiding bone cuts could increase the incidence of malalignment in primary TKA. Recent comparisons between patient-specific cutting guides and quantitative assessments of postoperative alignment have revealed the presence of outliers with respect to coronal alignment. The purpose of this study was to assess the implanted component alignment post-operatively between one type of MRI based PMI (Visionaire; Smith & Nephew, Inc, Memphis, Tenn) and conventional surgical instrumentation (CI) using radiographs and CT scan.

Methods

32 knees in 32 patients (25 women) with medial type knee osteoarthritis were underwent cruciate retaining TKA between September 2013 and May 2015, and were included in this study. Preoperative MRI scanning of the hip, knee, and ankle was performed for PMI group (n=12) and CT scanning was performed for CI group (n=20) 6 weeks before surgery according to a standard scanning protocol to determine the surgical epicondylar axis (SEA). Postoperatively, we compared operation time, blood loss, and mechanical alignment of two groups. Post-surgical mechanical alignments such as hip-knee-ankle angle (HKA), frontal femoral component angle (FFC), and frontal tibial component angle (FTC) were determined using long leg radiographs (Fig. 1). CT scans were used to assess the condylar twist angle (CTA) made by SEA and posterior condylar axis (Fig. 2). Each measurement was performed by two, blinded independent observers, and interclass correlation for each measurement was calculated. A student's two-tailed t test was used to compare the two cohorts, with statistical significance set at a p-value of <0.05.

Introduction

Rapid recovery protocols (RRP) for joint replacements have been shown to improve efficiency, reduce costs, and minimize adverse outcomes in academic health systems. The purpose of this study is to evaluate if RRP can be safely implemented in a community health system for total knee arthroplasty.

Methods

This study used a retrospective cohort of 3,608 patients who underwent primary unilateral total knee arthroplasty from January 1, 2013 to December 31, 2014. 60 Patients were excluded because data or surgery could not be verified: BMI less than 18.5 or greater than 60 kg/m∘2 or if the surgical time was less than 45 seconds or greater than 180 minutes, and bilateral surgery. Data was obtained from querying the health system's inpatient database containing information for all joint replacements within the system. Patients were compared in two groups: those who received a RRP after surgery versus those who received traditional post-op care. The main outcome measure was all-cause 30-day readmissions. Multivariate logistic regression was used to calculate the odds for all-cause 30-day readmission for patients who received RRP versus traditional care when controlling for age, gender, race, insurance status (Medicare versus no Medicare), obesity, diabetes, renal disease, tobacco use, and ASA score (less than 3 versus 3 or greater).

Introduction

The purpose of this study was to experimentally evaluate impingement and dislocation of total hip replacements while performing dynamic movements under physiological-like conditions. Therefore, a hardware-in-the-loop setup has been developed, in which a physical hip prosthesis actuated by an industrial robot interacts with an in situ-like environment mimicked by a musculoskeletal multibody simulation-model of the lower extremity.

Methods

The multibody model of the musculoskeletal system comprised rigid bone segments of the lower right extremity, which were mutually linked by ideal joints, and a trunk. All bone geometries were reconstructed from a computed tomography set preserving anatomical landmarks. Inertia properties were identified based on anthropometric data and by correlating bone density to Hounsfield units. Relevant muscles were modeled as Hill-type elements, passive forces due to capsular tissue have been neglected. Motion data were captured from a healthy subject performing dislocation-associated movements and were fed to the musculoskeletal multibody model. Subsequently, the robot moved and loaded a commercially available total hip prosthesis and closed the loop by feeding the physical contact information back to the simulation model. In this manner, a comprehensive parameter study analyzing the impact of implant position and design, joint loading, soft tissue damage and bone resection was implemented.

Introduction

Wear of the ultra-high molecular weight polyethylene (UHWMPE) component and the subsequent aseptic loosening remains a primary reason for late revision of total knee replacements (TKRs).[1] While improved measurement techniques have provided more quantitative information on the wear of surgically retrieved inserts, it is not well understood how observed damage patterns translate to volume loss of polyethylene in vivo. The overall purpose of this study is to investigate the relationship of damage patterns and volume loss at the articular surface of total knee replacements. We hypothesize that damage patterns are reliable predictors of volume loss.

Methods

Two different investigators independently analyzed damage patterns and volume loss on 43 revision- and 21 postmortem-retrieved MG II (Zimmer Inc.) tibial UHMWPE components. Areas of damage patterns on the articular surfaces were outlined with a video microscope (SmartScope, OGP) and were separated into four spatially exclusive categories (Fig. 1): delamination, pitting, striations and polishing. Articular surfaces were digitized with a low-incidence laser coordinate measuring machine (SmartScope, OGP). Autonomous reconstruction, a previously described and validated method,[2] calculated volume loss on the medial and lateral sides of each component. To investigate the predictability of volume loss using observed patterns, stepwise linear regression models were rendered in PASW Statistics 18 (SPSS Inc).

Background

Unexplained pain is one of the most common complications after Oxford UKAs. We have retrospectively reviewed the patients who underwent Oxford UKAs and investigated those patients with prolonged pain and found that many of these patients had strong tenderness over the Hunter canal and they were well treated with Hunter canal block or administration of Pregabalin. We have checked the details of these prolonged pain and key to the treatment will be discussed.

Methods

Between May 2006 and September 2014 we have performed 316 Oxford UKAs. There were 47 males and 269 females with average age of 70.4 years old (46–90). The patients were followed up for at least 6 months (6 months to 8.0 years, mean follow-up period of 3.1 years). The patients were examined both clinically and radiologically.

Objective

We have been using continuous epidural block and local infiltration cocktail for the pain management after TKA since 2005, and good pain control has been acquired with this method. During the past few years we have changed our protocol of postoperative pain management. We have stopped the administration of Loxoprofen starting next morning of the operation, instead Celecoxib was given starting before the operation. We have started mixing steroid to the intraoperative local infiltration cocktail to reduce acute pain as well as swelling. We also have stopped using suction drain, and delayed the timing of CPM start from day 2 to day 3.

Methods

This is case control study, and 78 cases of unilateral TKA were investigated for the study. All cases were anesthetized with continuous epidural block with intravenous dosage of phentanyl and propofol. Compositions of local infiltration cocktail are 40ml 0.75% Ropivacaine, 60ml saline, 0.5ml epinephrin. Group1 (n=40) used this cocktail independently, and Group2 (n=38) used this cocktail with addition of 40mg of triamcinolone(Fig.1). Local infiltration cocktail was used during operation, which was injected to the whole joint capsule. In group1 Loxoprofen was given starting next morning, in group 2 Celecoxib was given starting at 7am on the day of operation. In group1 suction tube was left for 2 days, where as in group2 no suction tube was used postoperatively, and continuous epidural block catheter was removed on postoperative day 2 in both groups. CPM was started at postoperative day 2 in group 1 and postoperative day 3 in group 2. Numerical Rating Scale (NRS) was used to analyze the pain. Circumferences of knee and thigh, as well as ROM of knee joint were measured periodically.

Aim

We report on our experience of 206 BHR procedures in patients aged 50 years or less with a minimum ten year follow-up. Clinical outcome scores, body mass index (BMI), gender and age were analysed to investigate resurfacing outcomes.

Methods

200 patients (158 males and 42 females) with an average operation age of 43.33 years (SD ±5.66) were investigated. There were 6 bilateral procedures The mean follow-up period was 12.44 years (SD ±1.71). The arthroplasties were completed between April 1999 and December 2002 by one surgeon. Data and outcome measurements were collected prospectively and analysed retrospectively. We evaluated Harris Hip Scores, Short Form-36 (SF-36v2) Scores, Tegner Activity Score Scores and McMaster Universities Osteoarthritis Index Scores (WOMAC) comparatively at preoperative, six month and yearly intervals.

Aim

Adverse tissue reactions have been a concern in relation to metal components, particularly in hip replacements. We look at a possible correlation between hip joint effusion and metal ion levels.

Materials and methods

56 patients,(42M, 14F) agreed to the study. All had metal-on-mental arthroplasties. Average age was 64.2 (SD 9.8). All patients were asymptomatic.

Ultrasound examination performed by one ultrasonographer, using a Sonosite M-Turbo machine with a C60X/5-2 MHz transducer.

Cobalt levels were assessed using an inductively coupled plasma mass spectrometer. Chromium levels were assessed using a graphite furnace atomic absorption spectrometer.

Introduction

Recently, a mobile-fluoroscopy unit was developed which can capture subjects performing unconstrained motions, more accurately replicating everyday demands that patients place on their TKA. The objective of this study was to analyze normal knee and various TKA while subjects perform both traditional and more challenging activities while under surveillance of a mobile fluoroscopy unit.

Methods

Two hundred and seventy-five knees were evaluated using mobile fluoroscopy, which tracks the patient and the joint of interest as they perform a set of activities. Mobile fluoroscopic surveillance was used to investigate patients with customized TKA and off the shelf TKA as well as subjects with posterior stabilized (PS) or posterior cruciate retaining (PCR) TKAs while performing the following activities: (1) deep knee bend, (2) chair-rise, (3) walking up and down steps, (4) normal walking, and/or (5) walking up and down a ramp (Figure 1). The mobile fluoroscopic unit captures images at 60 Hz using a flat panel X-ray detector and the unit follows the patient, using a marker-less system, while the patients perform each activity. Each video was digitized and analyzed to determine the 3D kinematics.

Introduction

Currently, knee and hip implants are evaluated experimentally using mechanical simulators or clinically using long-term follow-up. Unfortunately, it is not practical to mechanically evaluate all patient and surgical variables and predict the viability of implant success and/or performance. More recently, a validated mathematical model has been developed that can theoretically simulate new implant designs under in vivo conditions to predict joint forces kinematics and performance. Therefore, the objective of this study was to use a validated forward solution model (FSM) to evaluate new and existing implant designs, predicting mechanics of the hip and knee joints.

Methods

The model simulates the four quadriceps muscles, the complete hamstring muscle group, all three gluteus muscles, iliopsoas group, tensor fasciae latae, and an adductor muscle group. Other soft tissues include the patellar ligament, MCL, LCL, PCL, ACL, multiple ligaments connecting the patella to the femur, and the primary hip capsular ligaments (ischiofemoral, iliofemoral, and pubofemoral). The model was previously validated using telemetric implants and fluoroscopic results and is now being used to analyze multiple implant geometries. Virtual implantation allows for various surgical alignments to determine the effect of surgical errors. Furthermore, the model can simulate resecting, weakening, or tightening of soft tissues based on surgical errors or technique modifications.

Background

To conduct a systematic review and network meta-analysis of RCTs with the aims of comparing relevant clinical outcomes (i.e. VAS, WOMAC total and sub-score score, Lequesne Algofunctional index, joint space width change and adverse events) between diacerein, glucosamine and placebo.

Methods

Medline and Scopus databases were searched from inception to August 29th, 2014, using PubMed and Scopus search engines and included RCTs or quasi-experimental designs comparing clinical outcomes between treatments. Data were extracted from original studies. A network meta-analysis was performed by applying weight regression for continuous outcomes and a mixed-effect Poisson regression for dichotomous outcomes.

Background

To improve implant positioning in total knee arthroplasty (TKA) patient-specific instrumentation (PSI) has been introduced as alternative for conventional instrumentation (CI). Though the PSI technique offers interesting opportunities in TKA, there is no consensus about the effectiveness of PSI in comparison with CI and results concerning soft-tissue balancing remain unclear. Therefore, the primary aim of the present study was to investigate the varus-valgus laxity in extension and flexion in patients receiving a TKA using PSI compared with CI. Additionally, radiological, clinical and functional outcomes were assessed.

Methods

In this prospective randomization controlled trial, 42 patients with osteoarthritis received a Genesis II PS (Smith & Nephew, Memphis, Tennessee), with either PSI (Visionaire, Smith & Nephew) or CI (Smith & Nephew). Patients visited the hospital preoperative and postoperative after 6 weeks, 3 and 12 months. One-year postoperative varus-valgus laxity was measured in extension and flexion on stress radiographs. Additional assessments included: the hip-knee-ankle angle on long-leg radiographs, femoral and tibia component rotation on CT-scans, radiolucency, the Knee Society Score (KSS), VAS pain, VAS Satisfaction, Knee injury and Osteoarthritis Outcome score (KOOS), Patella score (Kujala), the University of California Los Angeles activity score (UCLA), the anterior-posterior laxity in 20° and 90° knee flexion, adverse events and complications. The outcome measures were compared using independent t-tests, non-parametric alternatives and repeated measurements, with a significance level of p<0.05.

BACKGROUND

During revision hip arthroplasty, removal of a well-fixed, ingrown metal acetabular component may not be possible. Therefore, a new polyethylene liner can be cemented into the existing shell via the cement locking mechanism. We report the indications, technique, and results of cementing an acetabular liner into a well-fixed cementless acetabular shell.

PATIENTS AND METHODS

All patients were given informed consent to participate in this study, and the study was approved by our hospital institutional review board. Of 95 revision total hip arthroplasty (THA) between 2005 and 2014, five hips in 5 patients (4 female and a male) were operated by the cemented socket into metal shell technique. The mean age was 70.6 years (range, 59–84 years) (Table 1).

Introduction

Hip Resurfacing has been shown to be a valuable treatment for younger osteoarthritis patients related to functional outcomes. On the other hand, there is a higher risk for potential neck fractures and there is serious concern over metal-ion release and related health risks associated with the current metal-on-metal designs. Neck-preserving, short-stem implants may be a good alternative for younger patients. The current study investigated patient-reported outcomes from resurfacing and total hip arthroplasty (THA) with a neck preserving, short-stem implant (Corin MiniHip®).

Methods

Hip disability and osteoarthritis outcome scores (HOOS) from a young group of patients (n= 52, age 48.9±6.1 years) who underwent hip resurfacing surgery and a cohort of patients who underwent MiniHip® THA surgery (n=73, age 48.2±6.6) were compared. MANCOVA analysis was conducted including follow-up period as covariate. To compare complexity of the surgical intervention, the average durations for both types of surgery were compared using non-parametric testing (Mann-Whitney's U).

Introduction

11%–19% of patients are unsatisfied with outcomes from Total Knee Arthroplasty (TKA). This may be due to problems of alignment or soft-tissue balancing. In TKA, often a neutral mechanical axis is established followed by soft tissue releases to balance and match the flexion/extension gaps with the distal femoral and proximal tibial resections at right angles to the mechanical axis. Potential issues with establishment of soft tissue balance are due to associated structures such as bone tissue of the knee, the static (or passive) stabilizers of the joint (medial and lateral collateral ligaments, capsule, and anterior and posterior cruciate ligaments), and the dynamic (or active) stabilizers around the knee. An optimized balance among these systems is crucial to the successful outcome of a TKA. Additionally, the importance of correct femoral rotation has been well documented due to its effect on patella alignment and flexion instability, range of motion, and polyethylene wear.

There are several methods used in TKA procedures to establish femoral component rotation. The more prominent ones are a conventional method of referencing to the posterior condylar axis with a standard external rotation of 3° (PCR), anterior-posterior line or “Whiteside's line” (AP axis), transepicondylar axis (TEA) (Figure 1), and the gap balancing technique, however, it is not yet clear, which method is superior for femoral rotational component alignment.

In the current study, we sought to investigate an alternative method based on soft-tissue, dynamic knee balancing (DKB) while using an alternative analysis approach. DKB dictates femoral component rotation on the basis of ligament balance and force measures. DKB has become more prominent in TKA surgeries. While retaining ligament balance in TKA, it is possible that this technique also leads to higher precision of rotational alignment to the anatomical axis. The primary objective of this study was to compare efficiency of DKB versus other methods for rotational implant alignment based on post-surgery computed tomography (CT).

Methods

31 patients underwent computer-navigated total knee arthroplasty for osteoarthritis with femoral rotation established via a flexion gap balance device (Synvasive eLibra). Alternative, hypothetical alignments were assessed based on anatomical landmarks during the surgery. Postoperative computed tomography (CT) scans were analyzed to investigate post-surgery rotational alignment. Repeated measures ANOVA and Cochran's Q test were utilized to test differences between the DKB method and the other techniques.

Introduction

The application of digital radiography in orthopaedic settings has facilitated the improvement in the retention and utilization of these images in pre and post-operative assessments [1]. In addition to the cost-effectiveness of such technology the use of digital imaging combined with advanced computer image processing software such as TraumaCadTM software system (TraumaCad, BRAINLAB, Westchester, IL, USA) can provide more accurate details about patients in total hip replacement arthroplasty (THA), a process traditionally called preoperative templating [2] by which intraoperative complications are minimized and overall surgical time is reduced[3]. In a study of 486 patients we demonstrated that patients demographic had significant effect on the outcome of the measurement and utilizing them in a predictive model had helped with improving the results [4]. In this study, we aimed to improve and optimize the proposed algorithm by utilizing more patients’ information and improving the model by using a nonlinear relationship. Our main hypothesis in this study was that the model would significantly predict the actual implant size based on the preoperative assessments.

Method

We analyzed the outcome of digital radiographs of 1018 patients who were treated with THA.

Digital radiographs were acquired in the anteroposterior view of the pelvis centered over the pubic symphysis. The hip was internally rotated 10° to 15°. We evaluated multiple interactions and nonlinear models and developed the most significant model based on the available clinical data.

Introduction

A variety of patient reported outcome (PRO) surveys have been established and validated to evaluate the effectiveness of surgical interventions. The Hip Disability and Osteoarthritis Outcome Score (HOOS) has been validated as one method to evaluate the effectiveness of total hip arthroplasty patients. This PRO facilitates the assessment of factors that alter patient outcomes in hip arthroplasty. This retrospective study assesses the effect of psychological post-operative expectations on HOOS in total hip arthroplasty patients. In this pilot study, patient data was collected for 499 patients using the AAOS established Musculoskeletal Outcomes Data Evaluation and Management System (MODEMS) [1] and HOOS surveys.

Method

Patient data was matched using similar preoperative HOOS scores to allow for comparable room for improvement in HOOS score postoperatively. These patients were placed into groups of high performers and low performers. HOOS is based on a 0 to 100 scale, 100 as the best. High performers were defined as those with a ratio of change in HOOS score between preoperative and postoperative over the highest difference in score possible (reaching a postoperative HOOS of 100) of 1. Low performers were defined as those with the aforementioned ratio, but under the value of 0.3. Using these defined groups we were able to compare the summation of patient specific MODEMS scores using a univariate regression. The HOOS growth ratio is calculated based on the following.

HOOS growth ratio = (HOOS postop – HOOS preop)/(100-HOOS preop)

A principal component analysis (PCA) was conducted to identify the significant group of factors that could identify changes in the outcome of 41 patients (20 low performers and 21 high performers).

Introduction

Previous studies of ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) hip bearings have focused on outcomes following primary surgery. Less is known about the utilization or outcomes of ceramic bearings in revision total hip arthroplasty (R-THA) for the Medicare population in the US. We asked (1) what is the utilization of ceramic bearings for R-THA in the Medicare population and how has it evolved over time; (2) does the use of C-PE bearings influence outcomes following R-THA as compared with metal-on-polyethylene (M-PE); and (3) does the use of COC bearings influence outcomes following R-THA as compared with M-PE?

Methods

A total of 31,809 Medicare patients (aged > 65y) who underwent R-THA between 2005 and 2013 with known bearing types were identified from the Medicare 100% inpatient sample administrative database. Outcomes of interest included relative risk of readmission (90 days) or infection, dislocation, rerevision, or mortality at any time point after revision. Propensity scores were developed to adjust for selection bias in the choice of bearing type at revision surgery. Cox regression incorporating propensity score stratification (10 levels) was then used to evaluate the impact of bearing surface selection on outcomes, after adjusting for patient-, hospital-, and surgeon-related factors.

Introduction

Previous studies of retrieved CoCr alloy femoral heads have identified imprinting of the stem taper surface features onto the interior head bore, leading researchers to hypothesize that stem taper microgrooves may influence taper corrosion. However, little is known about the role of stem taper surface morphology on the magnitude of in vivo corrosion damage. We designed a matched cohort retrieval study to examine this issue.

Methods

From a multi-institutional retrieval collection of over 3,000 THAs, 120 femoral head-stem pairs were analyzed for evidence of fretting and corrosion using a visual scoring technique based on the severity and extent of fretting and corrosion damage observed at the taper. A matched cohort design was used in which 60 CoCr head-stem pairs with a smooth stem taper were matched with 60 CoCr head-stem pairs having a micro-grooved surface, based on implantation time, flexural rigidity, apparent length of taper engagement, and head size. This study was adequately powered to detect a difference of 0.5 in corrosion scores between the two cohorts, with a power of 82% and 95% confidence. Both cohorts included CoCr and Ti-6-4 alloy femoral stems. A high precision roundness machine (Talyrond 585, Taylor Hobson, UK) was used to measure surface morphology and categorize the stem tapers into smooth vs. micro-grooved categories. Fretting and corrosion damage at the head/neck junction was characterized using a modified semi-quantitative adapted from the Goldberg method by three independent observers. This method separated corrosion damage into four visually determined categories: minimal, mild, moderate and severe damage.

Purpose

The purpose of this study is to evaluate the clinical outcomes and and radiological findings of primary total hip arthroplasty(THA) performed by using cemented polished femoral stem.

Materials and Methods

We retrospectively reviewed 91 hips (84 patients) that had undergone primary THA with cemented polished femoral stem after follow-up more than 10 years. The mean age at surgery was 57 years old (47 to 75). Mean follow up period was 12. 8 years(10.1 to 14). Clinical evaluation was performed using Harris hip score. The radiographic evaluation was performed in terms of the cementing technique, including of subsidence within the cement mantle, radiolucent lines at the cement-bone or cement-stem interface, cortical hypertrophy, and calcar resorption.

Purpose

This studyevaluated the results of the acetabular medial wall osteotomy to reconstruct the acetabulum in dysplastic hip during total hip athroplasty.

Materials and Methods

A total of 30 hips of 30 patients who underwent THA between March 1999 and October 2002 were clinically and radiogically evaluated. The average age at the time of operation was 46.5 years (range: 17 to 73 years), and the mean follow-up period was 5 years (range: 5.3 to 8.7 years). 26 cases, a cementless hemispherical acetabular cup and 4 cases, reinforced ring were inserted in the true acetabulum. Only 2 hips needed structural bone graft.

Introduction

Significant reduction in the wear of current orthopaedic bearing materials has made it challenging to isolate wear debris from simulator lubricants. Ceramics such as silicon nitride (SiN), as well as ceramic-like surface coatings on metal substrates have been explored as potential alternatives to conventional implant materials. Current isolation methods were designed for isolating conventional metal, UHMWPE and ceramic wear debris. The objective of this study was to develop methodology for isolation and characterisation of modern ceramic or ceramic-like coating particles and metal wear particles from serum lubricants under ultra-low wearing conditions. Sodium polytungstate (SPT) was used as a novel density gradient medium due to its properties, such as high water solubility, the fact that it is non-toxic and acts as a protein denaturant, coupled with a large density range of 1.1–3.0 g/cm3 in water.

Methods

SiN nanoparticles (<50nm nanopowder, Sigma-Aldrich) and clinically relevant cobalt-chromium wear debris were added to 25% (v/v) bovine serum lubricant at concentrations of 0.03 and 0.3 mm3/ million cycles. The particles were isolated by a newly developed method using SPT gradients. The sample volume was reduced by centrifuging the lubricant at 160,000 g for 3 h at 20°C. Then, re-suspended pellet was digested twice with 0.5 mg/ml proteinse K for 18 hours at 50°C in the presence of 0.5% (w/v) SDS. Particles were then isolated from partially hydrolysed proteins by density gradient ultracentrifugation at 270,000 g for 4 h using SPT gradients [Figure 1]. At the end of centrifugation, particles were pelleted at the bottom of the centrifuge tube, leaving protein fragments and other impurities suspended higher up the tube. Isolated particles were then washed with pyrogen free water, dispersed by sonication and filtered through 15 nm polycarbonate membrane filters for SEM and EDX analysis.

Introduction

Silicon nitride (SiN) is a recently introduced bearing material for THR that has shown potential in its bulk form and as a coating material on cobalt-chromium (CoCr) substrates. Previous studies have shown that SiN has low friction characteristics, low wear rates and high mechanical strength. Moreover, it has been shown to have osseointegration properties. However, there is limited evidence to support its biocompatibility as an implant material. The aim of this study was to investigate the responses of peripheral blood mononuclear cells (PBMNCs) isolated from healthy human volunteers and U937 human histiocytes (U937s) to SiN nanoparticles and CoCr wear particles.

Methods

SiN nanopowder (<50nm, Sigma UK) and CoCr wear particles (nanoscale, generated in a multidirectional pin-on-plate reciprocator) were heat-treated for 4 h at 180°C and dispersed by sonication for 10 min prior to their use in cell culture experiments. Whole peripheral blood was collected from healthy donors (ethics approval BIOSCI 10–108, University of Leeds). The PBMNCs were isolated using Lymphoprep® as a density gradient medium and incubated for 24 h in 5% (v/v) CO2at 37°C to allow attachment of mononuclear phagocytes. SiN and CoCr particles were then added to the phagocytes at a volume concentration of 50 µm3 particles per cell and cultured for 24 h in RPMI-1640 culture medium in 5% (v/v) CO2 at 37°C. Cells alone were used as a negative control and lipopolysaccharide (LPS; 200ng/ml) was used as a positive control. Cell viability was measured after 24 h by ATPLite assay and tumour necrosis factor alpha (TNF-α) release was measured by sandwich ELISA. U937s were co-cultured with SiN and CoCr particles at doses of 0.05, 0.5, 5 and 50 µm3 particles per cell for 24h in 5% (v/v) CO2 at 37 C. Cells alone were used as a negative control and camptothecin (2 µg/ml) was used as a positive control. Cell viability was measured after 0, 1, 3, 6 and 9 days. Results from cell viability assays and TNF-α response were expressed as mean ±95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis.

Introduction

Titanium nitride (TiN) coatings are used in total hip arthroplasty to reduce friction of bearing couples or to decrease the allergic potential of orthopaedic alloys. Little is known about performance of currently manufactured implants, since only few retrieval studies were performed, furthermore they included a small number of implants manufactured over 15 years ago.

Aim of study

To examine wear and degradation of retrieved TiN coated femoral heads articulating with ultra-high molecular weight polyethylene (UHMWPE).

Introduction

Backside wear of polyethylene (PE) inlays in fixed-bearing total knee replacement (TKR) generates high number of wear debris, but is poorly studied in modern plants with improved locking mechanisms.

Aim of study

Retrieval analysis of PE inlays from contemporary fixed bearing TKRs - to evaluate the relationship between backside wear and liner locking mechanism and material type and roughness of the tibial tray.

Introduction

Dislocation of an uncemented total hip replacement (THR) can cause damage to the femoral hear, when it passes through the rim of metal acetabular shell. This can lead to metal transfer on the surface of the head or chipping of bulk head material. Although dislocation is one of most common complications in total hip arthroplasty (THA), little is known if causes any further damage to the articulating surface of ceramic heads in long term observations.

Aim of the study

To evaluate, if dislocations of THR with ceramic on polyethylene bearing causes structural damage to the articulating surface of the femoral head in a follow-up of minium 10 years

Introduction

In a recent study we evaluated the clinical and radiographic long-term results as well as the serum metal concentrations of 105 cementless primary total hip prosthesis, performed between November 1992 and May 1994 with a 28-mm high-carbide-concentration metal-on-metal articulating surfaces. Forty-one patients who had had a total of forty-four arthroplasties were available for follow-up evaluation at a minimum of seventeen years postoperatively.

The median serum cobalt concentration of the patients with their hip replacement as the only source of cobalt was 0.7 µg/L (range 0.4–5.1µg/L), showing no significant difference to the previous study after a minimum of 10 years follow-up. We were investigating the systemic dissemination, which in turn, did not show more severe effects, such as carcinogenicity or renal failure. There are many complex issues associated with the analysis of metal ions, including collecting technique, analysis and reporting of the results. At the AAOS in March 2013, the Hip Society mentioned, that systemic ion levels are just one factor in the evaluation and should not be relied upon solely to determine the need for revision surgery. Furthermore, the correlation between cobalt or chromium serum, urin or synovial fluid levels and adverse local tissue reactions is incompletely understood.

Patients and Methods

In our present study we evaluated the serum, urin as well as the joint aspirate metal concentrations, of cementless total hip arthroplasties with a high-carbon, metal-on-metal bearing (Metasul®) at a mean of eighteen-years follow-up. We performed a correlation analysis to evaluate the relationship between these values and to determine whether elevated serum metal concentrations are associated with elevated and local metal concentrations and with early failure of metal-on-metal articulations.

Material and Methods

In a prospective randomized study of two groups of 65 patients each, we compared the acetabular component position when usingthe imageless navigation system compared to the freehand conventional technique for cementless total hip arthroplasty. The position of the component was determined postoperatively on computed tomographic scans of the pelvis.

Results

There was no significant difference for postoperative mean inclination (p=0.29), but a significant difference for mean postoperativ acetabular component anteversion (p=0.007), for mean deviation of the postoperative anteversion from the target position of 15°(p=0.02) and for the outliers regarding inclination (p=0.02) and anteversion (p<0.05) between the computer-assisted and the freehand-placement group.

Introduction

EOS® is a low dose imaging system which allows the acquisition of coupled AP and lateral high-definition images while the patient is in standing position. HipEos has been developped to perform pre-surgical planning including hip implants selection and virtual positioning in functional weight-bearing 3D. The software takes advantage of the real size 3D patient anatomical informations obtained from the EOS exam. The aim of this preliminary study on 30 consecutive THP patients was to analyze the data obtained from HipEos planning for acetabular and femoral parameters and to compare them with pre and post-operative measurements on standing EOS images.

Material and methods

Full body images were used to detect spino-pelvic abnormalities (scoliosis, pelvic rotation) and lower limbs discrepancies. One surgeon performed all THP using the same type of cementless implants (anterior approach, lateral decubitus). The minimum delay for post-op EOS controls was 10 months. A simulation of HipEos planning was performed retrospectively in a blinded way by the same surgeon after the EOS controls. All measurements were realized by an independent observer. Comparisons were done between pre and post-op status and the “ideal planning” taking in account the parameters for the restitution of joint offset and femur and global limb lengths according to the size of the selected implants. Regarding cup anteversion, the data included the anatomical anteversion (with reference to the anterior pelvic plane APP) and functionnal anteversion (according to the horizontal transverse plane in standing position).

Introduction

The combination of spinal fusion and THP is not exceptional. Disorders of the pelvic tilt and stiffness of the lumbosacral junction modify the adaptation options while standing or sitting. Adjusting the cup can be difficult and THP instability is a potential risk. This study reports an experience with EOS® simultaneous measurements on AP and lateral views of spine and hips in THP patients.

Material and methods

29 men and 45 women were included in this prospective study. 21cases had bilateral THP. Patients were separated into two groups: long fusions including the thoraco-lumbar junction (group 1) and shorter fusions below L1 (group 2). We analyzed the impact of the arthrodesis on the position of the pelvis by measuring variations of the sacral slope (SS) and APP angle. Cup position was defined by coronal inclination and functional anteversion in the horizontal plane standing and sitting. We compared the data to a previous series of 150 THP patients with asymptomatic and non fused spine.

Introduction

Rottinger published a description of an anterior muscle sparing approach to the hip. It utilizes the same muscle interval as the classic WatsonJones approach between the gluteus medius laterally and tensor fascia lata medially. However, this technique has the disadvantage of needing asplit table and a sterile bag to mobilize the operative leg as extension, adduction and external rotation are the key points for femoral preparation. This study describes our experience for an equivalent of the Watson Jones approach with a simplified technique for the femoral preparation.

Material and Methods

Incision starts 1cm distal and 3cm posterior to the ASIS and continues distally for about 8–10 cm along the straightline joining the lateral edge of the patella. It can be extended proximally or distally if necessary. The surgeon is placed posteriorly and the assistant anteriorly. The hip is dislocated with extension and external rotation to osteotomize the femoral neck. During the preparation of the acetabulum the femur is pushed posteriorly with internal rotation. Steinman pins are placed around the acetabulum to improve visualization for reaming and implanting theacetabular components. The femur is then exposed in a simplified way. The operated limb remains on the table. It is adducted above the contralateral limb and rotated outward to allow the femoral metaphysis to protrude. The foot is placed on the edge of the table beside the assistant, the knee is maintained with 45° flexion. The hip capsule is released postero-laterally to improve the femur exposure using Hohman retractors without cutting the short external rotator muscles. Femoral preparation is performed in this position. Once the appropriate implant is selected, the desired head trials are placed. The hip is reduced and the length and stability can be checked with the leg free. In case of isolated cup revision, the femoral head can be conserved. In case of femoral revision, a femorotomy can be easily performed due to the possibility of extended and stable exposure of the femur. Table 1 summarizes the main data of the series.

BACKGROUND

Despite many years of clinical experience the optimal bearing choice in total hip arthroplasty (THA) remains controversial. This study aims to directly compare the three widely used bearing surfaces: metal-on-highly crosslinked polyethylene (MoHXLPE), ceramic-on-ceramic (CoC) and metal-on-metal (MoM), regarding clinical and radiologic outcome parameters.

METHODS

From November 1999 to November 2001, 300 primary THAs were performed using the uncemented Alloclassic Variall cup and stem (Zimmer Inc., Warsaw, Indiana). The patients were divided into three groups according to the bearing couple implanted, with 100 persons in each group (MoHXLPE, CoC, MoM). Radiographic and clinical data was collected preoperative and at the last follow-up.

Purpose

There are still some controversies over the routine use of negative suction drainage after primary total hip arthroplasty (THA). In this study we are to know the benefits of new suction drainage management strategy after primary THA.

Materials and methods

From 2010 to 2012, two hundred patients who had unilateral primary THA were randomly allocated into two groups. One group had negative suction drainage immediately after THA (Group 1). In the other group, the suction drainage was inserted but negative pressure was applied more than 12 hours after surgery, in the morning postoperative day one (Group 2). All surgeries were performed by one single hip surgeon using the same technique and postoperative rehabilitation protocol was all same. We checked the amount of blood loss, changes in hemoglobin (Hb), volume of blood transfusion, superficial or deep wound infection and hematoma. Clinical results were evaluated using HHS score.

Objectives

C-reactive protein(CRP) Used as screening test for acute periprosthetic joint infection has high sensitivity and low specificity. So there are many reasons except acute infection after total knee arthroplasty to elevate CRP level but it is unclear what reasons exactly were concerned. We therefore performed this study to determine the Causes of elevated CRP level in the early-postoperative period after primary total knee arthroplasty.

Methods

Between 2005 and 2013, 502 patients undergone primary total knee arthroplasty were included. We excluded patients performed total knee arthroplasty with inflammatory arthritis and revision total knee arthroplasty, We measured the serial CRP levels in the all cases and then found cases with CRP level show elevation-depression-elevation pattern(bimodal graph) or >23.5mg/dl. We analyzed causes of elevated CRP level of that

Objectives

To evaluate the clinical and radiographic outcomes of total knee arthroplasty using Vega® Knee System (B Braun-Aesculap, Tuttlingen, Germany) [Fig. 1] designed to allow high flexion by shortening the length of posterior condylar flange of femoral component after at least 2 year and to assess the occurrence of periprosthetic osteolysis and loosening at final follow-up.

Materials and Methods

Of the patients who underwent total knee arthroplasty using Vega® Knee System between April 2011 and May 2013, 40 patients (46 knees) were enrolled. The mean age of the patients at the time of surgery was 72.3 years and the mean follow-up period was 29.4 months. Clinical parameters, including Knee Society Knee score, Knee Society Function score, maximal flexion and range of motion were evaluated. Relationship between postoperative maximal flexion and radiographic factors including the posterior tibial slope, the femoral condylar offset and the change of the posterior flange length of femoral condyle was analyzed. Also, the occurrence of periprosthetic osteolysis and loosening was assessed.

Introduction

Open wedge high tibial osteotomy (OWHTO) is an operation by the proper load re-distribution in the treatment for medial uni-compartmental arthritis of the knee joint. However, for the proper load re-distribution, stable fixation is mandatory. For the stable fixation, plate should be contoured to the bony surface and screws should be inserted from the central area of the medial side to the hinge area of the lateral side in the proximal fragment because most failures occur at the relatively lesser supported lateral hinge area. Therefore, the purpose of this study was to evaluate the screw insertion angle and orientation that is inserted to the direction of the lateral hinge with an anatomical plate that is post-contoured with a surface geometry of the proximal tibia after the OWHTO. The hypothesis of this study was that the position and orientation would be different according to the correction degree (median value 10 mm) and surgical technique (uni-planar vs bi-planar).

Materials and Methods

Thirty-one uni-planar and thirty-eight bi-planar osteotomies were evaluated. Postoperative CT data obtained after OWHTO were used for the 3D reconstruction of the proximal tibia. Anterior dimension (L1) and posterior dimension (L2) of the proximal tibia were measured in sagittal plane from tibial spine. Screw insertion points using four holes were even distributed using L1 and L2 value. As screw insertion angle was set from four holes to lateral hinge of the ‘Safe Zone’. Those four angles were measured in the axial and coronal plane. These were compared according to the correction degree and surgical technique.

Introduction

A large proportion of patients with osteoarthritis of the knee, present with bilateral symptoms at the outpatient department. A simultaneous total knee arthroplasty (TKA) procedure is available for such patients. The first operation in a simultaneous surgery may provide information to the operator to determine component size, soft tissue balancing, and estimate gap size for the second operation, while the second team usually conducts an operation in a confined space on the contralateral side during closure for the first operation, which can disturb cooperation during the second operation and may lead to more intra-operative surgical errors. We hypothesized that the circumstances of the two consecutive operations of a simultaneous bilateral TKA are different, could lead to different outcomes of overlapping bilateral TKAs. We therefore addressed the following research questions to determine whether there would be differences in short-term clinical outcomes, radiographic results, and implanted component size between the two sides

Methods

A retrospective review of 451 consecutive patients, who underwent simultaneous bilateral TKA between January 2011 and April 2012, was conducted. Bilateral TKAs were performed with the senior surgeon conducting the main procedure (from skin incision to implantation of first prosthesis until prior closure of the first knee) on the right side first and subsequently the left side with a second team. At 1 year after surgery, clinical outcome scores (the Knee Society Knee and Function scores, WOMAC score), radiologic findings were evaluated and clinical results as postoperative blood loss, operation time were compared between bilateral sides.

Introduction

Medial open wedge high tibial osteotomy (HTO) is a generally accepted surgical method for medial unicompartmental osteoarthritis with varus malalignment of the lower extremity. However, several authors have suggested the possibility of unintentional secondary changes during open wedge HTO, which include posterior tibial slope angle (PTS) change, tibial rotation change and medial–lateral slope change of the knee joint line, may influence knee kinematics and produce poor clinical outcomes. We sought to analyze postoperative changes in three-dimensional planes using a virtual wedge osteotomy 3D model. Pre- and post-operative changes in the medial proximal tibial angle (MPTA) in the coronal plane, posterior tibial slope (PTS) in the sagittal plane, and axial tibial rotation were measured as dependent variables. And this study was attempted to determine their mutual relationships and to clarify which independent variables, including hinge axis angle and gap ratio, affect tibial rotation change and PTS change by applying the identified hinge position.

Method

A total of 17 patients with 19 knees underwent HTO and were evaluated with 3D-CT before and after surgery. A 3D model was constructed by applying reverse engineering software.

Background

When reversing the hard-soft articulation in inverse shoulder replacement, i.e. hard inlay and soft glenosphere (cf. Figure 1), the tribological behaviour of such a pairing has to be tested thoroughly. Therefore, two hard materials for the inlay, CoCr alloy and alumina toughened zirconia ceramic (ceramys®) articulating on two soft materials, conventional UHMWPE and vitamin E stabilised, highly cross-linked PE (vitamys®) were tested in a joint simulator.

Methods

The simulator tests were performed at Endolab GmbH, Rosenheim, Germany, analogue to standardised gravimetric wear tests for hip prosthesis (ISO 14242-1) with load and motion curves adapted to the shoulder. The test parameters differing from the standard were the maximum force (1.0 kN) and the range of motion. A servo-hydraulic six station joint simulator (EndoLab) was used to run the tests up to 5*106 cycles with diluted calf serum at 37° C as lubricant. Visual inspection and mass measurements were done at 0.1, 0.5, 1, 2, 3, 4 and 5 million cycles using a high precision scale and a stereo microscope, respectivly.