Intraoperative Kinematics in Posterior Cruciate Ligament Retaining Total Knee Arthroplasty Using Different Inserts.

We analyzed the intraoperative kinematics of total knee arthroplasty (TKA) using a navigation system to investigate the influence of different inserts on kinematics. This was a retrospective observational study. The Vanguard individualized design (33 patients, 33 knees) XP and anterior-stabilized (AS) inserts were used in TKA for osteoarthritis. Kinematic data were intraoperatively recorded. The range of motion, tibiofemoral rotational angle, anteroposterior translation of the femur, and varus-valgus laxity were compared between the two inserts (XP vs. AS). There was no significant difference in the range of motion (extension: XP, 3.7° ± 3.3° vs. AS, 3.8° ± 3.3°, p = 0.84; flexion: XP, 138.1° ± 10.2° vs. AS, 139.0° ± 13.3°, p = 0.73). With the AS insert, the tibia was gradually internally rotated as the knee was flexed. At maximum extension, the internal rotation was smallest with AS (XP 6.5° ± 4.0° vs. AS 5.1° ± 3.4°, p = 0.022), which was also associated with smaller anterior femoral translation (maximum extension: XP, 14.1 ± 4.8 mm vs. AS, 11.3 ± 4.7 mm, p = 0.00036; 30°: XP, 23.7 ± 5.6 mm vs. AS, 20.7 ± 5.1 mm, p = 0.000033; 45°: XP, 24.4 ± 4.9 mm vs. AS, 23.2 ± 4.5 mm, p = 0.0038). The AS was associated with a lower varus-valgus laxity (30° XP 4.1° ± 3.4 vs. AS 3.3° ± 2.7°, p = 0.036; 60°: XP, 3.2° ± 3.0° vs. AS, 2.4° ± 3.3°, p = 0.0089). The AS insert facilitated sequential tibiofemoral rotation with varus-valgus stability in mid-flexion without restricting the range of motion.

Long-term conservative treatment outcomes for midshaft clavicle fractures: a 10-to-30-year follow-up.

BACKGROUND: Few reports exist on the long-term outcomes of midshaft clavicle fracture conservative treatments. Therefore, this study investigated the long-term outcome of this treatment in patients with midshaft clavicle fractures. METHODS: Patients were treated conservatively for midshaft clavicle fractures with a figure-of-eight bandage between 10 and 30 years ago. Subsequently, a telephone survey was used to follow-up these patients, and 38 were successfully evaluated. The mean term after trauma was 17.0 years. Afterward, the American Shoulder and Elbow Surgeons Shoulder (ASES) score and Shoulder pain and disability index (SPADI) on the affected and unaffected sides were calculated based on the filled questionnaires. We defined patients whose ASES and SPADI on the affected side were worse than the unaffected side as the symptomatic group. Furthermore, plain radiographs measured proportional changes in clavicular length and displacement. RESULTS: The ASES scores of the affected side were significantly lower than those of the unaffected side, and the SPADI of the affected side was significantly higher than that of the unaffected side. Furthermore, the symptomatic group's proportional changes in clavicular length and displacement were significantly larger than the asymptomatic group. CONCLUSION: The affected shoulder side was more symptomatic than the unaffected side 10 to 30 years after the trauma when midshaft clavicle fractures were treated conservatively. Moreover, several patients became symptomatic for fractures with a larger proportional change in clavicular length or displacement.

Incidence of clinical vertebral fractures and hip fractures of the elderly (65 years or over) population-large-scale data analysis using claim database in Kure City, Hiroshima, Japan.

Using the claim database, we investigated the incidence rate of clinical vertebral fractures per 1,000 in the elderly residents, over 65 years of age, in Kure city. The incidence rate, of clinical vertebral fractures, was 15.58 (7.29 male, 21.17 female, 2.90 female/male ratio). PURPOSE: To elucidate the incidence of clinical vertebral and hip fractures using the claim database, in those over 65 years of age in Kure city, and to compare with the previous reports. METHODS: We used, for residents in 2015, the medical care information of the National Health Insurance or Senior Elderly Care System in Kure City (Hiroshima Prefecture, Japan). Those with vertebral fractures as disease name, and either treatment/operation/hospitalization were defined as clinical vertebral fractures. Among the claim database, we extracted the clinical vertebral fracture and investigated the number of occurrences and the incidence rate per 1,000. We also investigated the incidence rate of hip fractures and compared those to the clinical vertebral fractures. RESULT: The incidence rate of clinical vertebral fractures of the elderly population (65 years or over) per 1,000 was 15.58 (7.29 male, 21.17 female, 2.90 female/male ratio). In both men and women, the incidence rate increased with aging. The incidence rate of hip fractures per 1,000 was 9.17 (3.55 male, 12.96 female, 3.65 male/female ratio). Clinical vertebral fractures were more frequent than hip fractures, and the ratio of incidence rate of vertebral fractures to hip fractures was 1.70 (male, 2.05, female, 1.63). For both fractures, the incidence rate increases with age, apart from the women where the incidence of vertebral fracture reduces slightly in the older age group CONCLUSION: This is the first report that investigated the incidence rate of the clinical vertebral fractures using the claim database, which covered almost the whole number of 230,000 population area.

Technical Considerations and Accuracy Improvement of Accelerometer-Based Portable Computer Navigation for Performing Distal Femoral Resection in Total Knee Arthroplasty.

BACKGROUND: Accelerometer-based computer navigation has been shown to be highly accurate for performing distal femoral and proximal tibial component alignment in total knee arthroplasty (TKA), although the procedure for the femoral component is less accurate than for the tibial component. METHODS: First, 30 knees without hip osteoarthritis or proximal femoral surgeries were selected. Sequential hip adduction, abduction, and flexion were performed, and the femoral head was monitored fluoroscopically in the coronal plane before TKA. Significantly more movement was detected during hip adduction than during abduction and flexion. Then, postoperative femoral and tibial component alignment was retrospectively evaluated in 48 TKAs before fluoroscopic monitoring (early group) and in the next 61 TKAs with femoral registration using smaller adduction movements to avoid large femoral head movements (later group). Another 47 TKAs treated with the conventional intramedullary method for the distal femoral component and the extramedullary method for the proximal tibial component were also analyzed (IM and EM group) for historic control. RESULTS: Significantly large variances in the femoral component implantation of the early group were detected in both the coronal and sagittal planes. The sagittal femoral implantation angle of the early group (4.6 ± 3.0°) was significantly larger than that of the later group (3.2 ± 1.8°) when 3.5° was the target for both groups. No significant difference was detected in the variances of either the coronal or sagittal tibial component implantation, although the coronal tibial implantation angle was significantly smaller (-1.3 ± 1.3°valgus) in the early group than in the other groups. CONCLUSION: Accelerometer-based navigation sometimes has technical issues during registration associated with hip adduction. We showed that femoral registration without large adduction movements will enable more accurate femoral implantation. Surgeons should also keep in mind that the coronal tibial component is likely to be in valgus alignment (about 1°) even if a neutral angle (0°) is selected with this particular device.

Intra-operative gaps affect outcome and postoperative kinematics in vivo following cruciate-retaining total knee arthroplasty.

PURPOSE: The following investigation evaluates the effect of intra-operative gaps after posterior cruciate ligament-retaining total knee arthroplasty using two-dimensional/three-dimensional registration and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). METHODS: Patients were divided into two groups according to their 90°-0° component gap changes using a device designed by our laboratory. The wide gap group was defined as more than 3 mm (4.3 ± 0.7 mm), and the narrow gap group was defined as less than 3 mm (1.3 ± 1.3 mm). RESULTS: Under non-WB (weight bearing) conditions, the wide flexion gap group (N = 10) showed a significant anterior displacement of the medial femoral condyle as compared with the narrow flexion gap group (N = 20). Despite no significant differences observed under WB conditions, both femoral condyle positions during flexion were significantly more posterior than during extension. WOMAC of the tight gap group showed worse scores for two functional items demanding knee flexion (bending to floor and getting on/off toilet). CONCLUSION: The large flexion gap could influence the late rollback under non-WB conditions and better WOMAC functional scores in the flexion items. Three to four millimetre laxity at 90°-0° component gaps may be adequate and might be necessary to carry out daily life activities.

Different femorotibial contact on the weight-bearing: midflexion between normal and varus aligned knees after total knee arthroplasty.

PURPOSE: The influence of residual malalignment on biomechanical analysis after total knee arthroplasty (TKA) is currently uncertain. The hypothesis is that postoperative alignment would influence the in vivo kinematics after TKA, under weight-bearing conditions but not under non-weight-bearing condition. The purpose of the present study was to compare weight-bearing and non-weight-bearing conditions and to evaluate the effect of the postoperative alignment on the in vivo kinematics after posterior cruciate ligament-retaining TKA during midflexion using 2-dimensional/3-dimensional registration. METHODS: Thirty knees of 30 patients with pre-operative varus deformity were divided into 2 groups according to their postoperative alignment: the normal alignment group (N = 21) and the varus alignment group (N = 9). RESULTS: Under weight-bearing conditions, the varus alignment group showed a significant posterior displacement of the medial femoral condyle (flexion: 80°, 90° P < 0.05) and a significant anterior displacement of the lateral femoral condyle (flexion: 10° P < 0.01, 20° P < 0.05, and extension: 10°, 20° P < 0.01, 30°, 40° P < 0.05) as compared with the normal alignment group. In contrast, no significant difference in the medial and lateral femoral condyle positions under non-weight-bearing conditions was observed between the normal and varus alignment groups. CONCLUSION: The postoperative alignment influenced knee kinematics under weight-bearing conditions. The weight load influenced knee kinematics through posterior tibial slope and induced greater lateral femoral condyle mobility, which might explain the better clinical and functional outcome. These findings contribute to gaining a proper understanding of the in vivo kinematics of the postoperative varus alignment and might be useful for orthopaedic surgeons in the achievement of patient satisfaction. LEVEL OF EVIDENCE: III.

Significant effect of the posterior tibial slope on the weight-bearing, midflexion in vivo kinematics after cruciate-retaining total knee arthroplasty.

The purpose of the present study was to compare weight bearing (WB) and non-WB conditions, and to evaluate the effect of the posterior tibial slope (PTS) on the in vivo kinematics of 21 knees after posterior cruciate ligament-retaining total knee arthroplasty during midflexion using 2-dimensional/3-dimensional registration. During WB, medial pivot and bicondylar rollback were observed. During non-WB, both the medial and lateral condyles moved significantly more anteriorly as compared to the WB state. These patients were divided into 2 groups according to their PTS. The large PTS group showed a significant posterior displacement of the medial femoral condyle as compared with the small PTS group, but no significant difference was observed at the lateral femoral condyle during both WB and non-WB. The PTS influenced knee kinematics through gravity (124/125).

Significant effect of the posterior tibial slope and medial/lateral ligament balance on knee flexion in total knee arthroplasty.

PURPOSE: The intra-operative femorotibial joint gap and ligament balance, the predictors affecting these gaps and their balances, as well as the postoperative knee flexion, were examined. These factors were assessed radiographically after a posterior cruciate-retaining total knee arthroplasty (TKA). The posterior condylar offset and posterior tibial slope have been reported as the most important intra-operative factors affecting cruciate-retaining-type TKAs. The joint gap and balance have not been investigated in assessments of the posterior condylar offset and the posterior tibial slope. METHODS: The femorotibial gap and medial/lateral ligament balance were measured with an offset-type tensor. The femorotibial gaps were measured at 0°, 45°, 90° and 135° of knee flexion, and various gap changes were calculated at 0°-90° and 0°-135°. Cruciate-retaining-type arthroplasties were performed in 98 knees with varus osteoarthritis. RESULTS: The 0°-90° femorotibial gap change was strongly affected by the posterior condylar offset value (postoperative posterior condylar offset subtracted by the preoperative posterior condylar offset). The 0°-135° femorotibial gap change was significantly correlated with the posterior tibial slope and the 135° medial/lateral ligament balance. The postoperative flexion angle was positively correlated with the preoperative flexion angle, γ angle and the posterior tibial slope. Multiple-regression analysis demonstrated that the preoperative flexion angle, γ angle, posterior tibial slope and 90° medial/lateral ligament balance were significant independent factors for the postoperative knee flexion angle. The flexion angle change (postoperative flexion angle subtracted by the preoperative flexion angle) was also strongly correlated with the preoperative flexion angle, posterior tibial slope and 90° medial/lateral ligament balance. CONCLUSION: The postoperative flexion angle is affected by multiple factors, especially in cruciate-retaining-type TKAs. However, it is important to pay attention not only to the posterior tibial slope, but also to the flexion medial/lateral ligament balance during surgery. A cruciate-retaining-type TKA has the potential to achieve both stability and a wide range of motion and to improve the patients' activities of daily living.

Mucoid degeneration of the posterior cruciate ligament: a case report.

We report a case of mucoid degeneration of the posterior cruciate ligament (PCL). A 37-year-old male had suffered from right knee pain for several years. The active range of motion of his right knee was -30 extension and 100 flexion, with terminal pain. Magnetic resonance imaging (MRI) showed low proton density and T2WI with fat saturation-high signals in the PCL. Arthroscopic resection of the PCL was carried out, with immediate relief of his symptoms. This was a very rare case of mucoid degeneration of the PCL in a young healthy man. If this disease is considered preoperatively, it can be diagnosed based on characteristic MRI findings.

Dislocation of the shoulder joint with ipsilateral humeral shaft fracture: two case reports.

INTRODUCTION: A combination of the shaft fracture of the humerus with shoulder dislocation is a rarely documented injury. Moreover, few reports describe a long-term outcome after a follow-up period over 10 years. The present article is the first report of long-term clinical results obtained with this combined injury. MATERIALS AND METHODS: We present two cases of the dislocation of the shoulder joint with ipsilateral humeral shaft fracture. One is an anterior dislocation and the other is posterior. The anterior dislocation was closely reduced on the date of injury, but the posterior dislocation required open reduction 6 weeks after the injury because it was missed at the initial diagnosis and identified 4 weeks after the injury. In the latter case, shoulder pain and limitation of the motion persisting after the first surgery had to be treated by anterior acromioplasty and arthrolysis of the shoulder. In both cases, the humeral fracture was fixed by retrograde intramedullary nailing using a Küntscher nail and successful bone union was achieved. RESULTS: At over 10-year follow-up examination, both patients had no limitation in activities of daily living and no restrictions to their normal occupation. The radiographs of the shoulder joint demonstrated good clinical results, with no degenerative change or osteonecrosis. CONCLUSION: We have experienced two cases of dislocation of the shoulder joint with ipsilateral humeral shaft fracture and reported long-term results over 10 years. Good clinical results were demonstrated in both cases.