Methods

The medical records of 75 patients who underwent surgery between 2000 and 2020 were retrospectively reviewed, and 44 patients who were alive and available for follow-up (at a mean of 9.7 years postoperatively) were included in the study. Leg length discrepancy was measured on whole-leg radiographs, and functional assessment was performed with PROMs (Toronto Extremity Salvage Score (TESS) and Comprehensive Outcome Measure for Musculoskeletal Oncology Lower Extremity (COMMON-LE)) with two different aspects. The thresholds for unfavourable PROMs were determined using anchor questions regarding satisfaction, and the risk factors for unfavourable PROMs were investigated.

Methods

This retrospective study included 255 patients who underwent 305 OUKAs with cementless tibial components. There were 52 males and 203 females. Their mean age was 73.1 years (47 to 91), and the mean follow-up was 1.9 years (1.0 to 2.0). In 217 knees in 187 patients in the conventional group, tibial cuts were made orthogonally to the tibial axis. The varus group included 88 knees in 68 patients, and tibial cuts were made slightly varus using a new osteotomy guide. Anterior and posterior KCDs and the origins of fracture lines were assessed using 3D CT scans one week postoperatively. The KCDs and rate of fracture were compared between the two groups.

Methods

The study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured.

Methods

A non-systematic search on PubMed was performed using keywords such as “impingement” or “tilt deformity” to find early anatomical descriptions of FAI. Relevant references from these primary studies were then followed up.

Methods

A total of 53 patients who underwent curved PAO (CPO) for DDH from January 2014 to April 2017 were selected. Three (5.7%) of them were lost to follow-up. Therefore, the data from 58 hips, contributed by 50 patients (44 women and 6 men), were included in the analysis. Pre- and postoperative computed tomography (CT) scans from the pelvis to the knee joint were performed and transferred to a 3D template software (Zed Hip; Lexi, Tokyo, Japan). The pelvic plane axis was defined according to the functional pelvic plane. The pre- and postoperative lateral and anterior 3D center-edge (CE) angles were measured on the coronal and sagittal views through the center of the femoral head. The pre- and postoperative 3D center-edge (CE) angles and femoral anteversion were measured and compared with clinical outcomes, including postoperative ROM.

Materials & Methods

Twenty-four patients (26 knees; 19 females, 7 males) underwent medial UKA were involved in this study. Average age was 74.8 ± 7.2 years. The mean preoperative active range of motion were − 4.1° ± 6.3°in extension and 123.2° ± 15.5° in flexion. All UKAs were performed using fixed bearing type UKA (Zimmer Biomet, ZUK), with adjusting the posterior slope of the proximal tibial bone cut according to the original geometry of the tibia. Routine lateral radiographies of the knee were examined preoperatively, 6 months after the surgery. PTS and knee extension angles with maximal active knee extension (mEXT) and one-leg standing (sEXT) were radiographically measured. We used the fibular shaft axis (FSA) for the sagittal mechanical axis of the tibia. PTS was defined as the angle between the medial tibial plateau and the perpendicular axis of FSA. Extension angles (mEXT and sEXT) were defined as the angles between FSA and distal femoral shaft axis (positive value for hyperextension). The changes of PTS and the influences of PTS on sEXT at each time period were analyzed using simple linear regression analysis (p<0.05).

Materials and Methods

A hundred knees of 88 consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker) were performed using computer assisted navigation system. The kinematic parameters of the soft-tissue balance, and amount of coronal relative movement between femur and tibia were obtained by interpreting kinematics, which display graphs throughout the range of motion (ROM) in the navigation system. Femoro-tibial alignments were recorded under the stress of varus and valgus before the procedure and after implantation of all components. In each ROM (0, 30, 60, 90, 120 degrees), the data of coronal relative movement between femur and tibia (tolerability) were analyzed before and after implantation. Furthermore, correlations between tolerability of varus/valgus and clinical improvement revealed by ROM and Knee society score (KSS) were analyzed by logistic regression analysis.

Material & Method

83 patients over 65 years old with osteoarthritic knees were involved in this study. All patients underwent CR-TKAs (Persona CR^R). The means and ranges of demographics were as follows: age; 74.5 years old (65–89), Hip-Knee-Ankle (HKA) angle; 12.4 (−6.2–22.5) in varus. We asked patients to fulfill the questionnaire including KSS-2011, FJS-12, EQ-5D and GLFS-25 at 1-year postoperative follow-up visit. KSS-2011 consisted of 4 categories of questions; patient satisfaction (PS), symptoms, patient expectations (PE), functional activities (FA).

We evaluated the correlation of PS to other PROMs using simple linear regression analyses (p<0.001).

Materials and Method

Seventy-three patients with varus type osteoarthritic (OA) knees underwent PS-TKA (Persona PS^R) were involved in this study. The mean age was 76.6 years old and preoperative HKA angle was 14.3 degrees in varus. Tibial bone cut was performed using standard extra-medullary guide with 7 degrees of posterior slope.

The tibial slopes were radiographically measured by post-operative lateral radiograph with posterior inclination in plus value. The angle between the perpendicular line of the proximal fibular shaft axis and the line drawn along the superior margin of the proximal tibia represented the tibial slope angle. We assessed one-year postoperative clinical outcomes including active range of motion (ROM), patient satisfaction and symptoms scores using 2011 Knee Society Score (2011 KSS).

The influences of posterior tibial slope on one-year postoperative parameters were analyzed using simple linear regression analysis (p<0.05).

Material & Method

The subjects were 94 patients underwent primary unilateral PS-TKA for varus type OA knees. The surgical technique was MPGT in 47 patients and MRT in 47 patients.

An originally developed off-set type tensor device was used to evaluate intraoperative soft tissue balance. In MPGT, medial release was limited until the spacer block corresponding to the bone thickness from proximal lateral tibial plateau could be easily inserted. Femoral component size and external rotation angle were adjusted depending on the differences of center gaps and varus angles between extension and flexion before posterior femoral condylar resection.

The knee stabilities at extension and flexion were assessed by stress radiographies at 1 and 3 years after TKA; varus-valgus stress test at extension and stress epicondylar view at flexion. We measured medial and lateral joint openings (MJO, LJO) at both knee extension and flexion.

MJOs and LJOs at 2 time periods were compared in each group using paired t-test. Each joint opening distance was compared between 2 groups using unpaired t-test. The significance level was set as P < 0.05.

Material & Method

The subjects were 140 patients underwent primary unilateral PS-TKA for varus type OA knees. The surgical technique was MPGT in 70 patients and MRT in 70 patients. There were no significant differences between two groups in the pre-operative clinical features including age, sex, ROM and deformity.

Originally developed off-set type tensor device was used to evaluate both center gap and varus angle with 40 lbs. of joint distraction force. The extension gap preparation was identical in both group. In MPGT group, femoral component size and external rotation angle were adjusted depending on the differences of center gaps and varus angles between extension and flexion before posterior femoral condylar osteotomy.

The knee stabilities at extension and flexion were assessed by stress radiographies; varus-valgus stress test with extension and stress epicondylar view with flexion, at one-month and one-year after TKA. We measured joint opening distance (mm) at medial and lateral compartment at both knee extension and flexion.

Joint opening distances were compared between two groups using unpaired t-test, and the difference between medial and lateral compartment in each group was compared using paired t- test (p<0.05).

Material and Methods

90 patients (80 females and 10 males) were involved in this study. The mean age at TKA was 75.2 ± 5.8 years. Patients were subjected to 3 meters timed up and go test (TUG) to evaluate ambulatory function. TUG was performed at 6 time periods; before surgery, 2 weeks, 1, 3, 6 months, and 1 year after surgery. We also asked the patients to fill out the questionnaire of patient satisfaction category in the New Knee Society Score at 1 year after TKA.

The sequential changes in TUG were analyzed using repeated measures ANOVA (p<0.05). The influences of each parameter (age, TUGs) on the patient satisfaction score were analyzed with simple regression analysis (p<0.05).

Materials & Methods

Sixty patients with varus osteoarthritis (OA) of the knee underwent CR-TKAs were included in this study. The mean age was 73.6 years old. Preoperative average varus deformity (HKA angle) was 12.5 degrees with long leg standing radiographs.

The knee stability and laxity at extension were assessed by stress radiographies; varus-valgus stress X-ray at one-month after operation. We measured joint separation distance (mm) at medial compartment with valgus stress as medial joint opening (MJO), and distance at lateral compartment with varus stress as lateral joint opening (LJO) at knee extension position. To analyze ligament balance; relative lateral laxity comparing to the medial, varus angle was calculated.

New Knee Society Score (NKSS) was used to evaluate the patient satisfaction at one-year after TKA.

We measured basic ambulatory functions using 3m timed up and go test (TUG) at one-year after surgery.

The influences of stability and laxity parameters (MJO, LJO and varus angle at extension) on one-year patient satisfaction and ambulatory function (TUG) was analyzed using single linear regression analysis (p<0.01).

Methods

Osteoarthritis was surgically induced by destabilization of the medial meniscus in eight-week-old C57BL/6 male mice. SRT1720 was administered intraperitoneally twice a week after surgery. Osteoarthritis progression was evaluated histologically using the Osteoarthritis Research Society International (OARSI) score at four, eight, 12 and 16 weeks. The expression of SIRT1, matrix metalloproteinase 13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), cleaved caspase-3, PARP p85, and acetylated nuclear factor (NF)-κB p65 in cartilage was examined by immunohistochemistry. Synovitis was also evaluated histologically. Primary mouse epiphyseal chondrocytes were treated with SRT1720 in the presence or absence of interleukin 1 beta (IL-1β), and gene expression changes were examined by real-time polymerase chain reaction (PCR).

Patients and Methods

This was a registry-based comparison of 1163 patients who had been treated for an isolated unstable pelvic ring fracture with (386 patients) or without (777 patients) EF. An isolated pelvic ring fracture was defined by an Abbreviated Injury Score (AIS) for other injuries of < 3. An unstable pelvic ring fracture was defined as having an AIS ≥ 4. The primary outcome of this study was mortality. A subgroup analysis was carried out for patients who required blood transfusion within 24 hours of arrival in the Emergency Department and those who had massive blood loss (AIS code: 852610.5). Propensity-score matching was used to identify a cohort like the EF and non-EF groups.

Patients and Methods

A total of 71 patients with 82 osteotomies were included in the study. Their mean age was 62.9 years (37 to 80). The classification of the type of osteotomy was based on whether it extended beyond the fibular head. The level of the osteotomy was classified according to the height of its endpoint.

Patients and Methods

The study involved 638 shoulders in 334 patients (175 men, 159 women, mean age 62.6 years; 25 to 81) with unilateral symptomatic rotator cuff tears. The cross-sectional area (CSA) of the LHB tendon in the bicipital groove was measured pre-operatively in both shoulders using ultrasound. There were 154 asymptomatic rotator cuff tears in the contralateral shoulder. Comparisons were made between those with a symptomatic tear, an asymptomatic tear and those with no rotator cuff tear. In the affected shoulders, the CSAs were compared in relation to the location and size of the rotator cuff tear.

Patients and Methods

A total of 60 TKAs (30 kinematically and 30 mechanically aligned) were performed in 60 patients with varus osteoarthritis of the knee using a navigation system. The angles of orientation of the joint line in relation to the floor, the conventional and true mechanical axis (tMA) (the line from the centre of the hip to the lowest point of the calcaneus) were compared, one year post-operatively, on single-leg and double-leg standing long leg radiographs between the groups. The range of movement and 2011 Knee Society Scores were also compared between the groups at that time.

Methods

Seventy-four consecutive medial UKAs were enrolled in this study. All the patients received a conventional fixed bearing UKA. Pre-operative (preop) and postop limb alignment was examined using long leg radiograph and lower limb alignment changes were calculated. Femoral and tibial osteotomy thickness were measured during surgery. Medial tibial joint line change was defined as polyethylene thickness minus tibial osteotomy thickness and sawblade thickness (1.27mm). Positive values indicated a tibial joint line elevation. Medial femoral joint line change was defined as femoral distal component thickness (6.5mm) minus femoral distal osteotomy thickness and sawblade thickness. Positive values indicated a femoral joint line reduction. Medial joint distraction width was also calculated by tibial joint line elevation plus femoral joint line reduction. The correlation of lower limb alignment change with polyethylene insert thickness, the medial tibial joint line elevation, femoral joint line reduction, or joint distraction width were analyzed.

Methods

A total of 96 TKAs of 69 patients and 61 UKAs of 50 patients were included. All patients presented with severe knee OA with hip-knee-ankle angle (HKA) ranged from −25 degree to −10 degree, preoperatively. Mean HKAs in TKA group and UKA group were −14.95º and −13.38º, respectively. PROs were assessed using Knee Society Score (KSS 2011), PainDETECT score (PD), and Pain Catastrophizing Scale (PCS) at a mean follow up of 58.65 months for TKA and 58.05 months for UKA. Kaplan-Meier survival analysis was performed to assess implant survival. Complication rate was also assessed. All data were compared between TKA group and UKA group.

Materials and Methods

Sixty-one consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker) were performed using computer assisted navigation system. During surgery, using a tensor device, after bony cut of femur and tibia, joint gaps were assessed in 0 and 90 degrees in flexion. Then, CS polyethylene tibial trial insert were inserted after trial implantation of femoral and tibial components, before and after resection of PCL, respectively. The kinematic parameters of the soft-tissue balance, and amount of coronal and sagittal relative movement between femur and tibia were obtained by interpreting kinematics, which display tables throughout the range of motion (ROM) in the navigation system. In each ROM (30, 45, 60, 90, max degrees), the data were analyzed with a ANOVA test, and mean values were compared by the multiple comparison test (Turkey HSD test) (p< 0.05).

Methods

Between March 2014 and March 2015, forty patients with varus osteoarthritis underwent primary TKA. All of the cases were using same types of implant (Triathlon; Stryker Orthopedics, Mahwah, NJ, USA), with an image-free navigation system (Stryker 4.0 image-free computer navigation system; Stryker). PCL was retained and cruciate substituting (CS) inserts were used in all cases. The mean age at the time of surgery was 71.7 ± 6.8 years old (ranging: 62 – 85). The mean follow-up was 10.9 ± 6.4 months. After minimum release of medial and lateral soft tissue, resection of anterior cruciate ligaments, and protection of PCL, registration and kinematic measurements were performed prior to bone resection. The kinematic measurements were performed again after implantation. The center of proximal tibial and distal femur were defined during registration. The point of proximal tibia was projected to the mechanical axis of femur and the distance between the projected point and the distal femur at 90° of flexion were measured and defined as femorotibial AP position. Distal relative to the center of distal femur indicates as minus, and proximal relative to the point indicates as plus. The correlation between the intraoperative changes of AP position and postoperative maximum flexion angles were investigated.

Introduction

In total knee arthroplasty, patients sometimes have pain in the posterolateral part of the knee. One possible cause is the impingement of the popliteus tendon against femoral components. In the literature, the incidence has been reported to be 1–4%. The purpose of this study was to compare of two prostheses on the amount of posterolateral overhang of the femoral component using Three-dimensional (3-D) templating software.

Methods

Sixty TKAs—30 kinematic and 30 mechanical aligned—were performed in patients with varus-type osteoarthritis using a navigation system. Using postoperative double-leg and single-leg standing long leg radiographs, joint line orientation angle to the floor, conventional mechanical axis (cMA), and true mechanical axis (tMA; line from hip center to the lowest point of calcaneus) were compared between the two groups. One-year after surgeries, range of motion and the patient-derived score of the 2011 Knee Society Score (2011 KSS), which includes four categories: symptoms, patient satisfaction, patient expectations, and functional activities, e.g., walking/standing, standard activities, advanced activities, and discretionary activities, were compared between the two groups

Materials & Methods

Seventy nine patients with varus type osteoarthritic knees underwent TKA were subjected to this study. The mean age of surgery was 72.4 years old. Preoperative standing coronal deformity was 9.6 degrees in varus. TUG test results in less duration with faster ambulatory function. TUG (seconds) was measured at 3 time periods; pre-operatively, at hospital discharge and 1year after surgery. To standardize TUG recovery time during 1 year after TKA, we defined TUG recovery rate as the percentage of recovery time to the pre-operative TUG as shown in the following equation. TUG recovery rate (%) = (TUG pre-op –TUG 1y po) / TUG pre-op ×100

We also evaluated the knee stability at hospital discharge and 1year after surgery. The knee stability at extension and flexion were assessed by varus and valgus stress radiography using Telos (10kg) and stress epicondylar view with 1.5kg weight at the ankle respectively. Image analyzing software was used to measure joint separation distance (mm) at medial as medial joint opening (MJO) and at lateral as lateral joint opening (LJO) at both knee extension and flexion. (Fig.1)

The sequential change of TUG was analyzed using repeated measures ANOVA (p<0.05). The influence of joint opening distances (MJO and LJO at extension and flexion) on TUG 1y po and TUG recovery rate were analyzed using simple linear regression analysis (p<0.05).

Materials and Methods

Twenty five consecutive subjects (24 women, 1 men; average age, 77 years; age range, 58–85 years) with varus osteoarthritis undergoing navigated BCS TKA (Journey II, Smith&Nephew) were enrolled in this study. An image-free navigation system (Stryker 4.0 image-free computer navigation system; Stryker) was used for the operation. Registration was performed after minimum medial soft tissue release, ACL and PCL resection, and osteophyte removal. Then, kinematics including tibiofemoral rotational angles from maximum extension to maximum flexion were recorded. The measurements were performed again after implantation. We compared the kinematics with the kinematics of paired matched fifty subjects who underwent conventional posterior stabilized (PS) TKA (25 subjects with Triathlon, Stryker; 25 subjects with PERSONA, ZimmerBiomet) using navigation statistically.

Objective

We compared intra-operative soft tissue balance between medial gap technique (MGT) and measured resection technique (MRT) in PS-TKAs.

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.

Materials and Methods

Twenty-four consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker) were performed using computer assisted navigation system. In all patients, difference between extension and flexion gap was under 3mm after bony cut of femur and tibia. During surgery, CS polyethylene tibial trial insert were inserted after trial implantation of femoral and tibial components, before and after resection of PCL, respectively. The kinematic parameters of the soft-tissue balance, and amount of coronal (valgus/varus), sagittal (anterior/posterior) and rotational relative movement between femur and tibia were obtained by interpreting kinematics, which display tables throughout the range of motion (ROM) (Figure1). During record of kinematics, the surgeon gently lifted the experimental thigh three times, flexing the hip and knee. In each ROM (30, 45, 60, 90, max degrees), the data were analyzed with paired t-test, and an ANOVA test, and mean values were compared by the multiple comparison test (Turkey HSD test) (p < 0.05).

Objective

In this study, we analyzed the effect of TKA on the ambulatory function by quantitative measurement using 2 simple performances test: TUG and ST.

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.

Objective

We introduced a new surgical technique (medial gap technique: MGT) according to modified gap technique regarding medial knee stability as important. The intra-operative soft tissue balance and post-operative knee stability were compared between MGT and MRT in posterior-stabilized (PS) TKA for varus type osteoarthritic knees.

Methods

We retrospectively analyzed 55 patients (43 women, 12 men) with osteoarthritis who underwent TKA using the same mobile-bearing CR-type implant (e.motion; B. Braun Aesculap, Germany). The mean age at the time of surgery was 74.2 (SD 7.3) years. The exclusion criteria for this study included valgus deformity, severe bony defect requiring bone graft or augmentation, revision TKA, active knee joint infection, and bilateral TKA. Intraoperative soft-tissue balance parameters such as varus ligament balance and joint component gap were measured in the navigation system (Orthopilot 4.2; B. Braun Aesculap) while applying 40-lb joint distraction force at 0°, 10°, 30°, 60°, 90°, and 120° of knee flexion using an offset-type tensor with the patella reduced. Varus ligament balance was defined as the angle (degree, positive value in varus imbalance) between the seesaw and platform plates of the tensor that was obtained from the values displayed by the navigation system. To determine clinical outcome, we measured knee flexion angle using a goniometer with the patient in the supine position before and 2 years after surgery. Correlations between the soft-tissue parameters and postoperative knee flexion angle were analyzed using simple linear regression models. Pre- and postoperative knee flexion angle were also analyzed in the same manner.

Materials and Methods

In surgery, the femoral neck was cut and prepared without using a box chisel, reamer or broaches, instead, a series of trial stems were used with the method of impaction technique. After impaction of cancellous bone with the final size of the trial stem, the stem is fixed by bone cement without taking any cement mantle. Full weight bearing was allowed for all patients from the next day of the surgery. We investigated short-term clinical and radiographic results and the incidence of complication that was related to this technique. Post-operative radiological results with the minimum follow-up of 12 months after surgery were analyzed in 31 joints (25 cases) with this technique. The mean age at the time of surgery was 66.3 years (46∼82). The mean duration after surgery was 62 months (14∼108).

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.

Methods

A cemented stem model was used for this study with a CPT stem into composite femur.

Three sizes of CPT stems (No. 1, No. 2 and No. 3) and one size composite femur were prepared for this study. We inserted two stems for each size, for a total of six stems. Composite femurs were reamed with a No. 3 rasp, and various size of stem was fixed with cement in each composite femur to make a various thicknesses of cement mantle. Two to three tantalum marker balls were injected into the cement in each femur before cement was hardened. 1-Hz dynamic load applied to the stems for half a-million cycles. Each 16 hours of loading was followed by 8 hours without loading. We used micro-CT before and after loading to measure the movement of the tantalum balls in three dimensions. And we analyzed occupation ratio of stem in the femoral canal by computed reconstructed three dimensional model of bone cement and stem.

Material and Methods

Twenty osteoarthritic varus knees were included in this study. After implantation of the trial components, PCL stiffness was measured using the original tension analyzer intra-operatively. Elastic modulus of PCL was calculated at 90 and 120 degrees knee flexion on two types of bearing surface.

Material and Method

Sixty patients with varus osteoarthritis of the knee underwent TKAs (30 CR TKAs: CR and 30 PS TKAs: PS). Mean varus deformity in standing position was 11.1 degrees in CR, and 12.6 degrees in PS. All TKAs were performed by a single surgeon with measured resection technique. The external rotation of posterior femoral condyle osteotomy was performed according to surgical epicondylar axis in pre-operative CT. We measured intra-operative soft tissue balance using an offset-type tensor with 40 lbs of joint distraction force at 0, 10, 30, 45, 60, 90, 120 and 135 degrees of flexion. The joint component gap (mm) and varus angle (degrees) were measured at each flexion angles.

One month, six months and one year after surgery, we evaluated the knee stability at extension by varus and valgus stress radiography using Telos (10kg) and at flexion by epicondylar view with 1.5kg weight at the ankle. We measured joint separation distance at medial as medial joint looseness (MJL) and at lateral as lateral joint looseness (LJL). Intra-operative measurements and post-operative joint stabilities were compared between CR and PS using unpaired t-test. The change of joint looseness in each group was analyzed using repeated measures ANOVA.

Methods

We investigated 12 hips in 10 patients who underwent THA. Preoperative CT imaging of the hip was performed, and 3-D reconstruction of the greater trochanter was used to visualize the bony impressions that indicate the insertions of the obturator internus and externus muscles (Fig 1A). We performed preoperative 3-D templating of two different femoral prosthesis (flat tapered-wedge stem: J-Taper, cylindrical straight stem: PerFix910) and then evaluated the extent of damage to the OA during the stem placement (Fig 1B, 1C). The extent of damage to the OA was classified using the following scale: grade 0, no damage of the insertion area; grade 1, less than 1/3; grade 2, equal to or more than 1/3–2/3; grade 3, equal to or more than 2/3; grade 4, complete.

Methods

We examined 12 patients (19 knees) implanted with a low contact stress (LCS) mobile-bearing TKA system using a two- to three-dimensional registration technique as previously reported [1]. All 12 patients were diagnosed with medial knee osteoarthritis. The in vivo kinematics of dynamic deep knee flexion under WB and non-WB (NWB) conditions were compared. We evaluated the knee range of motion, femoral axial rotation relative to the tibial component, anteroposterior translation, and kinematic pathway of the femorotibial contact point for both the medial and lateral sides.

Materials and Methods

Twenty-six patients with varus osteoarthritis undergoing navigated posterior-stabilized TKA (Triathlon, Stryker, Mahwah, NJ) were enrolled in this study. An image-free navigation system (Stryker 4.0 image-free computer navigation system; Stryker) was used for the operation. Registration was performed after minimum soft tissue release and osteophyte removal. Then, maximum internal and external rotational stress was manually applied on the knee with maximum extension and 90° flexion by the same surgeon, and the rotational angles were recorded using the navigation system. After knee implantation, the same rotational stress was applied and the rotational angles were recorded again. In addition, ROM was measured before surgery and at 1 month after surgery. The correlation between the amount of pre- and postoperative tibial rotation and ROM was statistically evaluated.

Methods

Twenty CR TKAs were performed in patients with moderate varus-type osteoarthritis (10° < varus deformity <20°) using the tibia first technique guided by a navigation system (Orthopilot). During the process of medial release, knee kinematics including tibial internal rotation and anterior translation during knee flexion were assessed using the navigation system at 3 points; (1) after anterior cruciate ligament resection (pre-release), (2) medial tibial and femoral osteophyte removal and release of minimum deep layer of medial collateral ligament (minimum release) and (3) release of semimembranosus (semimembranosus release). In addition, the kinematics after all prostheses implantation (semimembranosus release group) were assessed and compared with those assessed in another 20 patients in which only minimum release was performed (minimum release group).

Methods

Thirty-three hips from 24 consecutive patients undergoing THA were enrolled. The mean age was 65.3 years. Preoperative diagnoses included hip osteoarthritis in 27 hips, rheumatoid arthritis in 4 hips, idiopathic osteonecrosis in 1 hip, femoral neck fracture in 1 hip. Preoperative CT of the hip region was obtained and three-dimensional (3D) reconstruction of the greater trochanter was performed to visualize the bony impressions, that we called the obturator tendon attachment (OTA), indicating the attachment area of the obturator internus and externus muscles.

Material & Method

120 varus type osteoarthritic knees implanted with PS TKAs (NexGen LPS flex: Zimmer) were subjected to this study. All TKAs were performed using measured resection technique with anterior reference.

The femoral component size was evaluated intra-operatively using conventional femoral sizing jig. The selected femoral component size was expressed by the antero-posterior (AP) size increase (mm) comparing to that of original femoral condyles. Gap measurements were performed using a newly developed offset type tensor device applying 40lbs (178N) of joint distraction force. Firstly, conventional osteotomy gaps (mm) were measured at extension and flexion. Secondary, component gaps (mm) after femoral trial placement with PF joint reduced were evaluated at 0° and 90° of knee flexion.

To compare conventional osteotomy gaps and component gaps, estimated extension and flexion gaps were calculated by subtracting the femoral component thickness at extension (9mm) and flexion (11mm) from conventional osteotomy gaps respectively. The decrease of gap at extension and flexion were calculated with estimated gaps subtracted by component gaps. The simple linear regression analysis was used to evaluate the influence of selected femoral component size on the decrease of gap after femoral component placement.

Methods

Thirty UKAs for isolated medial compartmental osteoarthritis or idiopathic osteonecrosis were assessed. The mean age was 71.8±8.5 years old (range: 58–85), and the average coronal plane femorotibial angle (FTA) was 181.2±3.2 degree preoperatively. All the patients received a conventional medial Zimmer Unicompartmental High Flex Knee System (Zimmer Inc, Warsaw, Ind). The actual values of the proximal and posterior femoral osteotomy were calculated by adding the thickness of the bone saw blades to the thickness of the bony cut. Using a UKA tensor which designed to facilitate intra-operative soft tissue tension throughout the range of motion (ROM), the original gap before the femoral osteotomy, the component gap after the femoral osteotomy, and component placement were assessed under 20 lb distraction forces. (Figure 1)