Predicting independence of gait by assessing sitting balance through sitting posturography in patients with subacute hemiplegic stroke.

BACKGROUND: Post-stroke sitting balance is a known predictor of independence of gait after stroke. However, previous studies used only qualitative scales or measured static or dynamic sitting balance alone. OBJECTIVES: To investigate whether quantitative parameters of sitting posturography at post-stroke 1 month can predict independent gait. METHODS: In this prospective cohort study, we enrolled patients with first-ever stroke who could hold a sitting posture at post-stroke 1 month. Sitting balance was assessed using posturography at post-stroke 1 month. Independence of gait was assessed using functional ambulation categories at post-stroke 2 months. We predicted mobility independence at post-stroke 2 months according to sitting balance at post-stroke 1 month. We also assessed the correlation between sitting posturography parameters and clinical scales. RESULTS: We enrolled 27 patients. The limit of stability deviation predicted independent gait at post stroke 2 months (cutoff, 78.4%). Further, there was a high degree of correlation between sitting posturography parameters (weight-bearing distribution deviation and limit of stability deviation) and Berg Balance Scale (ρ = 0.763, ρ = 0.777; p < .001, respectively), Scale for Assessment and Rating of Ataxia (ρ = -0.853, ρ = -0.929; p < .001, respectively), and Fugl-Meyer Assessment scale (upper extremities: ρ = 0.520, ρ = 0.480 [p = .005, p = .011, respectively]; lower extremities: ρ = 0.744, ρ = 0.564 [p < .001, p = .002, respectively]) scores. CONCLUSIONS: Sitting posturography parameters is clinically useful because they can quantitatively assess post-stroke balance and neurological impairment and predict post-stroke independence of gait even when patients cannot reach their arms forward or stand upright.

Suggested Assessments for Sarcopenia in Patients With Stroke Who Can Walk Independently.

OBJECTIVE: To investigate variables for assessment of stroke-related sarcopenia that are alternative options to the current assessment for sarcopenia, which focuses on age-related sarcopenia and also has limitations in addressing sarcopenia due to weakness resulting from stroke. METHODS: Forty patients (17 men, 23 women; mean age, 66.9±15.4 years) with first-ever stroke who can walk independently were included. Muscle mass was determined by measuring ultrasonographic muscle thickness of vastus intermedius, rectus femoris, tibialis anterior, medial gastrocnemius, and biceps brachii muscles in addition to using the skeletal muscle index (SMI) with bioelectrical impedance analysis. Muscle strength was assessed with the Medical Research Council (MRC) sum score as well as handgrip (HG) strength. Physical performance was measured by the Berg Balance Scale (BBS) along with 4-meter gait speed (4MGS). Correlations between each assessment in the three categories were analyzed and adjusted by stroke severity, comorbidity, and nutritional status. RESULTS: For muscle mass, SMI showed the highest correlation with the tibialis anterior muscle (r=0.783, p<0.001) among the other muscles. Regarding muscle strength, the MRC sum score correlated with the HG (r=0.660, p<0.001). For physical performance, the BBS correlated with the 4MGS (r=0.834, p<0.001). The same result was obtained after adjusting for factors of stroke severity, comorbidity, and nutritional status. CONCLUSION: These results suggest that ultrasonographic muscle thickness of the tibialis anterior, the MRC sum score, and BBS might be alternatives to SMI, HG, and usual gait speed for sarcopenia in stroke patients.

Impact of Sleep Disorder as a Risk Factor for Dementia in Men and Women.

Sleep is an essential physiological process, especially for proper brain function through the formation of new pathways and processing information and cognition. Therefore, when sleep is insufficient, this can result in pathophysiologic conditions. Sleep deficiency is a risk factor for various conditions, including dementia, diabetes, and obesity. Recent studies have shown that there are differences in the prevalence of sleep disorders between genders. Insomnia, the most common type of sleep disorder, has been reported to have a higher incidence in females than in males. However, sex/gender differences in other sleep disorder subtypes are not thoroughly understood. Currently, increasing evidence suggests that gender issues should be considered important when prescribing medicine. Therefore, an investigation of the gender-dependent differences in sleep disorders is required. In this review, we first describe sex/gender differences not only in the prevalence of sleep disorders by category but in the efficacy of sleep medications. In addition, we summarize sex/gender differences in the impact of sleep disorders on incident dementia. This may help understand gender-dependent pathogenesis of sleep disorders and develop therapeutic strategies in men and women.

Early Identification of Risk Factors for Mobility Decline Among Hospitalized Older Patients.

OBJECTIVE: The aim of the study was to identify the risk factors for mobility decline among hospitalized older patients early. DESIGN: This is a prospective cohort study. A total of 875 older patients were divided into two groups: older patients with and without mobility decline. The mobility level was measured using the item of functional mobility in the Geriatric Screening for Care 10. The change in mobility between admission and discharge was determined as the dependent variable. There were a total of 18 independent variables, which consisted of three demographic variables, 10 most problematic domains of geriatric care, and five other health-related variables. A multivariable logistic regression analysis was conducted to identify the risk factors for mobility decline during hospitalization. RESULTS: Of the 875 older patients, 135 (15.4%) experienced mobility decline during hospitalization. The multivariable logistic regression analysis revealed female sex, cognitive impairment, and underweight as the risk factors for mobility decline during hospitalization. CONCLUSIONS: The identified risk factors should be considered to identify patients at a risk of mobility decline early and to provide targeted interventions, which can prevent mobility decline.

Does Adequate Lumbar Segmental Motion Reflect Recovery Process in Acute Lumbar Disc Herniation?

OBJECTIVE: To investigate if the extent of lumbar segmental motion is correlated with the recovery process in the form of pain intensity in patients with acute single level lumbar disc herniation (LDH). METHODS: A retrospective review of medical records was performed on patients presented with acute low back pain from January 2011 to December 2017. With prerequisites of undergoing both lumbar spine magnetic resonance imaging and functional radiography, patients with etiologies other than single level LDH were excluded. A total of 46 patients were selected, including 27 patients with disc herniation at L4-5 level and 19 patients at L5-S1 level. Pearson correlation analysis of pain intensity against segmental range of motion (sROM) and percentage of sROM of each lumbar segment was performed at the initial evaluation point and follow-ups. RESULTS: Serial documentation of pain intensity and functional radiography exhibited an inverse correlation between changes in visual analogue scale (VAS) and sROM in single level LDH at L4-5 level (r=-0.69, p<0.05). In addition, percentage of sROM showed a negative correlation with pain intensity at the aforementioned segment (r=-0.74, p<0.05). Initial pain intensity was also inversely correlated to sROM of the affected segment (r=-0.83, p<0.01 at L4-5; r=-0.82, p<0.05 at L5-S1). CONCLUSION: Improvement in sagittal mobility of the affected segment in LDH adequately reflected mitigation of low back pain during the recovery process. This conjunction could illustrate that the involved segment is overcoming natural immobilization, evidently demonstrating an inverse relationship between initial pain intensity and limitation of sagittal range of motion.

Influence of soft tissue balancing and distal femoral resection on flexion contracture in navigated total knee arthroplasty.

PURPOSE: The purpose of this study was to evaluate the influence of intra-operative soft tissue balancing and distal femoral cutting on flexion contracture in navigated TKA. METHODS: This was a prospective cohort study. Fifty-nine patients of primary navigation-assisted TKA were included with over 15° of flexion contracture and excluded valgus knees. Among the cases, 43 cases were performed with soft tissue balancing procedures only, and 16 cases were performed with soft tissue balancing and additional distal femoral bone cutting. The mean preoperative flexion contracture was 17.5° ± 2.7°. The angles of flexion contracture were recorded at each surgical step with navigation. RESULTS: The mean difference in flexion contracture angle between initial angle and angle after medial release was 5.2° ± 2.8°. The mean difference in flexion contracture angle between medial release step and after posterior cruciate ligament (PCL) release was 2.5° ± 2.2°. The mean difference in flexion contracture angle between PCL release step and after routine bone cutting was 3.1° ± 3.2°. The mean difference in flexion contracture angle between after trial insertion and after posterior clearing procedure was 2.7° ± 1.9°. Among the cases, TKA with 2 mm additional bone cutting were performed in 16 cases. The mean difference in flexion contracture angle after additional femoral bone cutting was 4.8° ± 2.1°. CONCLUSION: The medial release and 2 mm additional bone cutting could correct flexion contracture by 5°. The appropriate soft tissue balancing and bone cutting could correct flexion contracture intra-operatively up to 5° in each step. LEVEL OF EVIDENCE: II.

Time-dependent clinical results of rotating-platform total knee arthroplasty according to mechanical axis deviation.

PURPOSE: We hypothesized that the low contact stress (LCS) posterior stabilization system in knees with ≤3° deviation of coronal alignment would provide more favorable clinical outcomes and survival rate over the course of time. MATERIALS AND METHODS: A retrospective study was performed on 253 consecutive cases of primary total knee arthroplasty (TKA). Patients were classified according to the degree of deviation of coronal alignment on the initial postoperative radiograph as Group 1 (≤3° deviation) and Group 2 (>3° deviation). The clinical assessments were performed using the Knee Society score and Hospital for Special Surgery systems and Western Ontario and McMaster Universities index. RESULTS: The survival rate was 97.4% in Group 1 and 96.8% in Group 2. No statistically significant intergroup difference was observed in the clinical scores before surgery and since 1 year after surgery (p>0.05). However, a significant intergroup difference was noted between 6 months to 1 year after surgery (p<0.001). Less than 2 mm radiolucent lines were found more frequently in Group 2. Time-dependent improvement was noted within one year after TKA in both groups. CONCLUSIONS: Most of the expected improvements were achieved at 6 months after surgery in Group 1 and at 1 year after surgery in Group 2. The present study suggests that the LCS system yields time-dependent improvement regardless of coronal alignment deviation.

An improved technique for removing intramedullary antibiotic beads in osteomyelitis of the tibial shaft.

BACKGROUND: The intramedullary insertion of antibiotic-impregnated cement beads is used widely for the treatment of intramedullary infection. This report describes an improved technique for removing chains of antibiotic beads inserted into the intramedullary cavity. METHODS: We examined four cases in three patients of the intramedullary insertion of chains of antibiotic-impregnated cement beads for the treatment of osteomyelitis of the diaphysis of the tibia after the fixation of fractures with interlocking nails. During bead removal, the tip of an intramedullary guidewire was bent into a hook shape and was then engaged with the chain of impacted beads. The guidewire was removed from the intramedullary cavity, permitting the extraction of any beads adhering to the wire. RESULTS: As beads came into contact with the tip of the intramedullary guidewire, they could be extracted easily. No additional incision or bone fenestration was required. CONCLUSIONS: The use of a hook-shaped intramedullary guidewire simplifies the removal of chains of antibiotic-impregnated cement beads without the need for an invasive procedure. This technique makes the use of chains of cement beads a favorable choice for treating intramedullary infection.

Second-look arthroscopy after surgical treatment of Schatzker type II plateau fractures through the lateral submeniscal approach.

MAIN PROBLEM: To evaluate cartilage healing using second-look arthroscopic examination in tibia plateau fracture patients who have undergone open reduction and internal fixation with a submeniscal approach technique. METHODS: Between January 2007 and January 2010, we used second-look arthroscopy during 18-24-month follow-up of 20 patients with Schatzkar type II tibial plateau fractures who had undergone open reduction and internal fixation with a submeniscal approach technique. We classified patients according to step-off, knee range of motion, and Knee Society Score, and compared the results with those obtained by arthroscopy. RESULTS: Radiologically, 16 cases (80 %) were reduced within 2 mm of step-off. In 11 of these cases, according to the Outerbridge classification, we checked for chondromalacia from grade II to III. We observed 2 mm of step-off in four cases, and each had chondromalacia of at least grade III. The Knee Society Score was associated with chondromalacia grade (p < 0.05). CONCLUSION: Even in patients with normal joint range of motion and good clinical and radiological results, the actual condition of the articular cartilage varied significantly. Therefore, more long-term and regular follow-up is needed for proximal plateau fractures.

Comparison of double-bundle anterior cruciate ligament (ACL) reconstruction and single-bundle reconstruction with remnant pull-out suture.

PURPOSE: The purpose of this study was to evaluate the stability and functional outcomes of anterior cruciate ligament (ACL) reconstruction by tensioning of the ACL remnant using pull-out sutures compared with ACL double-bundle reconstruction. METHODS: Forty-four patients were included in single-bundle reconstruction with remnant tensioning group (Group 1), and 56 patients were included in the double-bundle reconstruction group (Group 2). The remnant tissue was tensioned to the direction of posterolateral bundle, which unrelated to the type of remnant bundle. Objective knee stability was evaluated by anterior stress radiography, KT-1000 and lateral pivot shift tests. The Tegner activity scale, International Knee Documentation Committee and OrthopädischeArbeitsgruppeKnie scoring systems were used for clinical evaluation. RESULTS: No statistically significant intergroup differences were observed in mechanical stability and clinical results (n.s). However, surgical time of remnant tensioning group is shorter than double-bundle reconstruction group (P = 0.005). CONCLUSION: Remnant tensioning suture with single-bundle reconstruction could be used with positive results as good as double-bundle technique if a good ACL remnant was found bridging the femur and tibia, rather than debride or damage to the remnant tissue during operation. LEVEL OF EVIDENCE: Retrospective, comparative cohort study, Level IV.

Lymphoma with unusual manifestations resembling acute osteomyelitis in bilateral ankles of an 8-year-old boy: a case report.

Early proper diagnosis of non-Hodgkin's lymphoma is critical. However, without a high index of suspicion, the diagnosis can often be missed because of the nonspecific symptoms and normal plain radiographs. Further, non-Hodgkin's lymphoma can be misdiagnosed as an infectious condition - such as osteomyelitis or septic arthritis - or as an inflammatory disease. The authors report a case of mature B-cell lymphoma of the small intestine or colorectal primary malignancy with peritoneal seeding and multiple bone metastases in an 8-year-old boy. This case report emphasizes the importance of a comprehensive approach with patients, including children with nonspecific symptoms, to orthopedic surgeons.

Revision Posterior Cruciate Ligament Reconstruction with a Modified Tibial-Inlay Double-Bundle Technique.

INTRODUCTION: We present the surgical technique for arthroscopic revision posterior cruciate ligament (PCL) reconstruction with use of the modified tibial-inlay double-bundle method without a change of the patient's position from supine to prone. STEP 1 GRAFT PREPARATION: Create the Achilles tendon allograft as a tibial bone block with two femoral bundles. STEP 2 PATIENT POSITION: With the patient in the supine position, flexion, abduction, and external rotation of the hip and flexion of the knee 60° to 90° can provide easier access to the popliteal area. STEP 3 FEMORAL TUNNEL PREPARATION: Make anterolateral and posteromedial femoral tunnels in a shallow-shallow position using an outside-in technique for the anterolateral bundle and the inside-out technique for the posteromedial bundle. STEP 4 TIBIAL TUNNEL PREPARATION: Make the tibial tunnel with the patient supine with the hip flexed, abducted, and externally rotated and the knee flexed 60° to 90° to provide easier access to the popliteal area. STEP 5 GRAFT PASSAGE: Using a wire loop, pass the graft through the knee joint posterior to the intercondylar notch into the femoral tunnel. STEP 6 GRAFT FIXATION: Use a cannulated screw with a spiked washer to secure fixation of the bone block to the tibia. STEP 7 POSTOPERATIVE REHABILITATION: Rehabilitation after a PCL repair is generally more conservative than the accelerated rehabilitation used after an ACL repair. RESULTS: In our study, twenty-two patients (twenty men and two women; mean age, 37.4 years) were treated with revision PCL reconstruction performed with the described technique and followed for a mean of 39.6 months (range, twenty-four to seventy-two months)14.IndicationsContraindicationsPitfalls & Challenges.

First case report of an intracortical lipoma in an adult tibia.

The current case report describes an adult male with an intracortical lipoma accompanied by cystic changes in the tibial diaphysis. To the best of our knowledge, intracortical lipoma in an adult tibia has not been previously described. An anteroposterior radiograph of the tibia revealed an osteolytic lesion on the diaphysis. Magnetic resonance imaging and computed tomography revealed that the lesion was located in the cortex and consisted of fat and cyst tissue. Surgical excision of the lesion confirmed diagnosis of an intracortical lipoma.

Remnant preservation is helpful to obtain good clinical results in posterior cruciate ligament reconstruction: comparison of clinical results of three techniques.

BACKGROUND: The purpose of the present study was to compare the clinical results of 3 posterior cruciate ligament reconstruction techniques according to the time from injury to surgery and remnant PCL status and to evaluate the efficiency of each technique. METHODS: The records of 89 patients who underwent primary PCL reconstructions with a posterolateral corner sling were analyzed retrospectively. Thirty-four patients were treated by anterolateral bundle (ALB) reconstruction with preservation of the remnant PCL using a transtibial tunnel technique in the acute and subacute stages of injury (group 1). Forty patients were treated with remnant PCL tensioning and an ALB reconstruction using the modified inlay technique in the chronic stage (group 2), and fifteen patients were treated with double-bundle reconstruction using the modified inlay technique (group 3). The double-bundle reconstruction was performed if there was a very weak or no PCL remnant. RESULTS: The mean side-to-side differences in posterior tibial translation on the stress radiographs were reduced from 10.1 ± 2.5 mm in group 1, 10.6 ± 2.4 mm in group 2, and 12.8 ± 3.2 mm in group 3 preoperatively to 2.3 ± 1.4 mm in group 1, 2.3 ± 1.5 mm in group 2, and 4.0 ± 2.5 mm in group 3 at the last follow-up (p < 0.001, p < 0.001, and p < 0.001, respectively). Statistical analyses revealed that group 1 and group 2 were similar in terms of side-to-side difference changes in posterior tibial translation on the stress radiographs; however, group 3 was inferior to group 1 and group 2 at the last follow-up (p = 0.022). The clinical results were not significantly different among the three groups. CONCLUSIONS: Excellent posterior stability and good clinical results were achieved with ALB reconstruction preserving the injured remnant PCL in the acute and subacute stages and remnant PCL tensioning with ALB reconstruction in the chronic stage. The PCL injuries could be surgically corrected with different techniques depending on both the remnant PCL status and the interval between the knee trauma and operation.

Early postoperative analgesic effects of a single epidural injection of ropivacaine administered preoperatively in posterior lumbar interbody spinal arthrodesis: a pilot randomized controlled trial.

BACKGROUND: Despite the suitable characteristics of ropivacaine as an epidural analgesic agent, such as better preservation of motor function and less neurotoxicity, we are aware of no data on its clinical application in pain management following lumbar spine surgery. The purpose of the present study was to evaluate the preemptive analgesic effects and safety of a single epidural injection of ropivacaine during lumbar arthrodesis. METHODS: We performed a randomized, double-blinded, intention-to-treat study. Patients with planned one-level posterior lumbar interbody arthrodesis were randomly assigned to either the injection group (n = 32) or the control group (n = 34). The injection group received a 10-mL epidural injection of 0.1% ropivacaine twenty minutes before the skin incision at the planned vertebral level, and the control group received an epidural injection of 10 mL of 0.9% saline solution. A numeric rating scale (from 0 to 10) was measured at seven time points after surgery (at two, four, eight, twelve, twenty-four, and forty-eight hours and at the time of discharge), and the frequency of pushed-button patient-controlled analgesia and total fentanyl consumption were assessed at similar time points (up to two, up to four, up to eight, up to twelve, up to twenty-four, and up to forty-eight hours after surgery). Postoperative nausea and vomiting, the duration of the hospital stay, and the Likert satisfaction score at the time of discharge were evaluated. RESULTS: There were no significant differences between the two groups preoperatively. The numeric rating scale score was higher until twelve hours (p < 0.05) and the frequency of button pushes was higher at every time point except eight to twelve hours (p < 0.05) in the control group as compared with the injection group. Fentanyl consumption until eight to twelve hours (p < 0.05) and total consumption (p < 0.001) at discharge were higher in the control group. There were no differences between the two groups in terms of postoperative nausea and vomiting, the duration of hospital stay, or the mean satisfaction score, and no transient motor weakness was seen in relation to epidural injection of ropivacaine. CONCLUSIONS: A single-dose epidural injection of 0.1% ropivacaine before lumbar spine surgery is effective for reducing early postoperative pain without related complications such as transient motor weakness.

The isometry of two different paths for remnant-preserving posterior cruciate ligament reconstruction.

PURPOSE: It is reported that the length of the posterior cruciate ligament (PCL) fibres increases as the knee flexes, and the magnitude of the length change reaches up to 9.8 mm throughout the range of motion, which exceeds the range of failure strain. Therefore, we postulated that a compensatory mechanism must be recruited to overcome this large strain in order to maintain physiologic function as a key component of joint kinematics. Our main objective was to compare the length change pattern for the linear distance between the femoral and tibial tunnels with the length change patterns derived from a real isometer test of different curvatures. METHODS: We utilized ten intact cadaveric knees and created a vertical femoral tunnel (5 mm medial to the roof of the intercondylar notch and 5 mm proximal from the articular margin) and lateral tibial tunnels (5 mm proximal to the posterior bony ridge on the lateral side of the PCL fibre) and performed a 3D-CT scan at 0º, 30º, 60º, 90º, and 120º. The distances between the femoral and tibial tunnels were calculated from the 3D coordinates. Real isometry was checked both (1) over the PCL and (2) under the PCL using an isometer with an accuracy of 0.1 mm. RESULTS: The path over the PCL had the longest intra-articular length, followed by the path under the PCL, and the lengths measured by CT, respectively. The path over the PCL had a more curved path compared with the path under the PCL and the lengths measured by CT. The lengths measured by CT showed significantly larger excursion than the real isometer test. The path over the PCL showed the least excursion through the range of motion, followed by the path under the PCL, and the lengths measured by CT, respectively. CONCLUSION: Our findings suggested that a more curved PCL path has better isometry because the curvature of the PCL compensates for the length change between 0º and 60º flexion. In remnant preservation PCL reconstruction, the passage of graft over the PCL would have increased intra-articular length and better isometry compared with straight under the PCL path. LEVEL OF EVIDENCE: Basic science study.

High tibial open wedge osteotomy below the tibial tubercle: clinical and radiographic results.

PURPOSE: The purpose of this study was to evaluate the clinical and radiographic results of open wedge HTO below the tubercle for genu varum in relatively young patients. METHODS: Thirty-seven knees in 19 patients with genu varum treated by open wedge HTO below the tubercle between 2001 and 2008 were retrospectively studied. Median follow-up was 36 months (12-108), and median patient age at the time of surgery was 26 years (16-45). Clinical results were evaluated using Lysholm knee scores and Hospital for Special Surgery knee scores. Satisfaction with the results of surgery (0-10 points) was subjectively evaluated using operative scar (1-5 points) and leg shape (1-5 points) results at follow-up. Radiographic evaluations were made using: (1) tibiofemoral angles, (2) mechanical axis deviations, (3) varus-valgus inclinations of the tibial plateau, (4) tibial slopes, and (5) Insall-Savati and (6) Blackburne-Peel ratios. RESULTS: All but one patient achieved radiographic healing and union at the osteotomy site at an average of 3 months postoperatively. Average Lysholm knee score improved from 89.4 ± 8.7 preoperatively to 98.6 ± 2.5 at final follow-up (P = 0.0001), and mean HSS score improved from 91.1 ± 5.6 preoperatively to 98.5 ± 2.0 at final follow-up (P = 0.0001). Mean patient satisfaction score at final follow-up was 8.6 ± 1.0, and mean tibiofemoral angle increased from -1.6° preoperatively to 7.7° at final follow-up (P < 0.0001). The point where the mechanical axis crosses the tibial plateau also shifted significantly from 15.0% preoperatively to 50.6% at final follow-up (P = 0.0002). However, mean posterior tibial slope did not change significantly (9.7° preoperatively and 8.7° at final follow-up; P = NS), and neither did patella heights as measured by Insall-Savati and Blackburne-Peel ratios. CONCLUSION: Both functional assessment and radiographic measures indicated that HTO below the tibial tubercle leads to significant improvements in radiographic parameters and knee function without changes in patellar height or posterior tibial slope. The results obtained support the hypotheses that opening wedge HTO below the tibial tubercle should be recommended in relatively young patients with genu varum. LEVEL OF EVIDENCE: Therapeutic study, Level IV.

Less femoral lift-off and better femoral alignment in TKA using computer-assisted surgery.

PURPOSE: A comparison has been made between navigation-assisted and conventional measured resection total knee arthroplasty (TKA), under the hypothesis that navigation assistance would improve the precision and consistency of component alignment and femoral component rotation. METHODS: The following radiographic parameters were measured: mechanical femorotibial angle, coronal and sagittal component angle, and femoral component rotation. Femoral condylar lift-off was checked by axial radiographs, and thresholds for outliers were set at 1.0 mm. RESULTS: Clinical results obtained using Knee Society and Hospital for Special Surgery systems were not statistically different. The mean mechanical femorotibial angle was 2.2° (SD: 0.9) in the conventional group and 1.7° (SD: 0.7) in navigation group (p = 0.001). The mean coronal femoral component angle was 89.2° (SD: 2.2) in conventional group and 90.4° (SD: 1.8) in navigation group (p = 0.006). The mean transepicondylar-posterior condylar axis angle was 1.7° (SD: 0.9) in conventional group and 1.2° (SD: 0.5) in navigation group (p = 0.008). Femoral condylar lift-off greater than 1 mm occurred more frequently (p = 0.000) in conventional group. CONCLUSION: Coronal plane stability and precision of femoral component rotation were impacted by navigation system. The use of a navigation system with measured resection TKA can help optimize coronal stability and parallel component position. LEVEL OF EVIDENCE: Retrospective case control study, Level IV.

Comparison of the clinical outcomes after total knee arthroplasty with the LCS rotating platform mobile bearing knee system and the PFC Sigma RP-F mobile bearing knee system.

BACKGROUND: We compared clinical outcomes after total knee arthroplasty with the Low Contact Stress (LCS) rotating platform mobile bearing knee system and the Press Fit Condylar Sigma rotating platform high flexion (PFC Sigma RP-F) mobile bearing knee system. METHODS: Fifty cases of total knee arthroplasty were performed with the PFC Sigma RP-F mobile bearing knee system and sixty-one cases were performed with the LCS mobile bearing total knee arthroplasty. The average duration of follow-up was 2.9 years. RESULTS: The mean Hospital for Special Surgery (HSS) knee score was 62.1 (range, 52 to 75) in the LCS group and 61.9 (range, 50 to 74) in the Sigma RP-F group preoperatively, and 90.1 (range, 84 to 100) in the LCS group and 89.8 (range, 83 to 100) in the Sigma RP-F group at the final follow-up. The mean preoperative flexion contracture was 6.7° (range, 0° to 10°) in the LCS group and 9.3° (range, 0° to 15°) in the Sigma RP-F group preoperatively. The mean range of motion was 124.6° (range, 105° to 150°) in the LCS group and 126.1° (range, 104° to 145°) in the Sigma RP-F group at the final follow-up. CONCLUSIONS: After a minimum duration of follow-up of two years, we found no significant differences between the two groups with regard to the range of knee motion or the clinical or radiographic results.