Intraoperative avulsion fracture of the intercondylar eminence in Oxford mobile-bearing unicompartmental knee arthroplasty: Case report.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) can provide good postoperative results and long term survival, but there may be complications. We present a rare case of avulsion fracture of the intercondylar eminence during UKA surgery. CASE PRESENTATION: An 88-year-old man had right-knee pain with anteromedial osteoarthritis. Oxford partial knee UKA (Zimmer Biomet, Warsaw, IN) was performed by the senior author by the under-vastus approach using Microplasty instruments. During the final check of the range of motion, an avulsion fracture of the intercondylar eminence occurred at the terminal extension. A 4.0 mm cannulated cancellous screw was inserted into the intercondylar eminence from just in front of the anterior cruciate ligament to the posterior tibial cortex. Six months postoperatively, bony fusion was confirmed by lateral radiography. Two years after the surgery, the patient was fully satisfied. The flexion angle was 125°, but still with an extension limit of 10°. DISCUSSION: Avulsion fracture of the intercondylar eminence can be caused by hyperextension and/or the ACL becoming tighter in full extension of the knee. In this patient, avulsion fracture also probably occurred due to increased tension of the ACL in the fully extended position. After making the horizontal cut, we inserted a thin metal plate to prevent deeper vertical cuts, but an excessive horizontal cut was a possible cause of the fracture. As treatment for avulsion fracture of the intercondylar eminence, fixation of the cannulated cancellous screw resulted in uneventful bone fusion. We recommend having a cannulated cancellous screw at hand for such complications and for other potential intraoperative problems, such as tibial plateau fracture. Further investigation into limited postoperative extension might be needed. CONCLUSION: Our patient had intraoperative avulsion fracture of the intercondylar eminence, a relatively rare complication of Oxford UKA which is probably caused by the extension being tight and/or an excessive horizontal cut. Having a cannulated cancellous screw at hand is advised, and attention should be paid to postoperative limit of extension.

Current concept of kinematic alignment total knee arthroplasty and its derivatives.

The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA, the tibial cutting surface is decided parallel to the femoral cutting surface (or trial component) with in-line traction. These approaches are categorized as unrestricted KA because there is no consideration of leg alignment or component orientation. Restricted KA is an approach where the periarthritic joint surface is replicated within a safe range, due to concerns about extreme alignments that have been considered 'alignment outliers' in the neutral mechanical alignment approach. More recently, functional alignment and inverse kinematic alignment have been advocated, where bone cuts are made following intraoperative planning, using intraoperative measurements acquired with computer assistance to fulfill good coordination of soft-tissue balance and alignment. The KA-TKA approach aims to restore the patients' own harmony of three knee elements (morphology, soft-tissue balance, and alignment) and eventually the patients' own kinematics. The respective approaches start from different points corresponding to one of the elements, yet each aim for the same goal, although the existing implants and techniques have not yet perfectly fulfilled that goal.

Approximately 80% of Japanese osteoarthritic patients fall out of the safety range in restricted kinematically-aligned total knee arthroplasty in an analysis of preoperative long-leg radiograms.

BACKGROUND: Restricted kinematically-aligned total knee arthroplasty (KA-TKA) is a reasonable modification to avoid the alignment outlier that may cause implant failure. However, despite a noted high incidence of constitutional varus in Japanese individuals, there has been no investigation into how many knees require the restriction in restricted KA-TKA (RKA-TKA) among Japanese patients. Therefore, we conducted a study using preoperative long-leg radiograms. METHODS: We studied long-leg radiographs of 228 knees in 114 consecutive patients. The numbers of knees within the safety range and their corrective osteotomy angle in the restriction algorithms advocated by Almaawi et al. (2017) and MacDessi et al. (2020) were evaluated. RESULTS: According to the algorithms used by Almaawi et al. and MacDessi et al., out of 228 knees, 46 (20%) and 39 (17%) fell within the safety range, respectively. The mean correction angles of the hip-knee-ankle angle, lateral distal femoral angle and medial proximal tibial angle were 2.8 ± 3.4°, 0.4 ± 1.4° and 2.4 ± 2.8° in the algorithm used by Almaawi et al., while they were -4.9 ± 4.7°, 1.1 ± 2.5° and -6.0 ± 3.4° in the algorithm used by MacDessi et al. Most of the knees needed to be restricted in order to perform RKA-TKA, regardless of the algorithm used. CONCLUSIONS: Based on a preoperative analysis of long-leg radiograms in a Japanese population, most knees fall out of the safety range in RKA-TKA. Surgeons must consider whether to allow component outlier or to perform corrective osteotomy that likely requires soft tissue release.

Bearing Separation From the Lateral Wall of the Tibial Component Is a Risk of Anterior Dislocation of the Mobile Bearing in Oxford Unicompartmental Knee Arthroplasty.

BACKGROUND: Bearing dislocation is a serious complication after Oxford unicompartmental knee arthroplasty. Bearing separation from the lateral wall can cause it to spin (90° horizontal rotation) and eventually dislocate because there is just a 2 mm difference in height in both the lateral and medial sides from the bottom of the bearing, compared with the anterior (5 mm) and posterior (3 mm) sides. The details of this problem have not been previously examined. METHODS: Twenty-one dislocations in 12 patients were retrospectively analyzed. Bearing separation was defined as the bearing position being sufficiently distant from the lateral wall of the tibial component to allow spinning. We analyzed the incidence of separation, the direction and the recurrence of the dislocations, and their causes and treatments. RESULTS: Five of the 12 patients had separation. Of the total of 21 dislocations, 11 occurred in cases of separation (52%). Seven of 11 anterior dislocations were found to have separation, whereas nine of 13 posterior dislocations occurred without separation (P = .0237). Three of 5 patients with separation had recurrence of dislocation, and eventually 2 underwent revision to fixed-bearing unicompartmental knee arthroplasty. CONCLUSION: Bearing separation from the lateral wall of the tibial component can cause bearing dislocation, especially in an anterior direction. To prevent separation, the wall-bearing distance should be evaluated before the keel slot preparation, with manipulation as necessary. Conversely, posterior dislocation was predominant in our nonseparation cases.

Low photoelastic and optical properties in RO-SnO-P2O5 (R = Zn, Ba, Sr) glasses.

We report transparent RO-SnO-P2O5 (R=Zn, Ba, Sr) glasses with low photoelastic constant less than ∼1 B (1×10(-12) Pa(-1)) and high refractive index more than ∼1.65. The BaO or SrO substitution effect of SnO on optical properties is nearly the same as ZnO substitution of the ternary zinc tin-phosphate glass without hazardous oxide. A new series of BaO-SnO-P2O5 glass characterized with a very low photoelastic constant of ∼0.08 B, high refractive index (∼1.66), and better water durability is a candidate for precise polarization control devices such as optical filters and beam splitters.

Zero photoelastic zinc tin phosphate glass without lead oxide.

The photoelastic constant (PEC) is evaluated for 15 zinc tin phosphate glasses in a series of xZnO-(67-x)SnO-33P(2)O(5) where x is 0-30 mol. % at 0.5-7 mol. % intervals. The phase retardation of polarized light, passing through a disk sample with applying various uniaxial loads, was measured for PEC determinations by using a frequency stabilized transverse Zeeman He-Ne laser as a polarized light source. The substitution of ZnO for SnO results in the increase of PEC from negative to positive values in the range of -1.43 and +1.45×10(-12) Pa(-1). The minimum PEC value of 0.04±0.02×10(-12) Pa(-1) was experimentally obtained in the 18.5 mol. % ZnO-48.5 mol. % SnO-33 mol. % P(2)O(5) glass.

Elucidation of codoping effects on the solubility enhancement of Er3+ in SiO2 glass: striking difference between Al and P codoping.

The codoping effect mechanism of Al and P on the solubility enhancement of Er(3+) ion in SiO(2) glass was clarified by electron spin-echo envelope modulation spectroscopy. It turned out that doped P ions preferentially coordinate to the Er(3+) ion to form a "solvation shell structure", and the environment is similar to that in phosphate glass, while doped Al ions do not form such a selective solvation structure, taking octahedral coordination. This striking difference indicates that the primary roles of the P-doping and the Al-doping are attributed to "enthalpy of mixing" and to "entropy of mixing", respectively.

Comparative study of harvest-site complications following coronary artery bypass grafting between the radial artery and the saphenous vein in identical patients.

PURPOSE: The aim of this study was to assess the early outcome for complications associated with the radial artery harvest site, in comparison to using the saphenous vein, in patients harvested for both vessels. METHODS: During the last 2 years, 134 radial arteries were used in 133 patients, and the saphenous vein was also concomitantly used in 94 patients. We assessed the post-harvest forearm perception using a questionnaire that contained two statements regarding pain and numbness in those 94 patients. The incidences of the harvest-site hematoma and infection were also compared between both the arms and legs where the grafts were harvested. RESULTS: Numbness of the harvest site was indicated in 26.6% (radial artery) and 33.0% (saphenous vein), respectively (P = 0.4252). Hematoma was found in 6.4% and 12.8%, respectively (P = 0.2152). On the other hand, the incidences of pain and wound infection were significantly lower in the radial artery sites (pain: 1.1% vs 23.4%, P = 0.0002; infection: 2.1% vs 11.7%, P = 0.0182). CONCLUSIONS: Our early experience suggests that the use of the radial artery is safe and also demonstrates a lower incidence of harvest-site complications than saphenous vein harvesting in patients where both vessels are used as harvest sites.

Determining the best procedure for radial artery harvest: prospective randomized trial for early postharvest complications.

OBJECTIVE: Although useful procedures for radial artery harvest have been reported, forearm circulation and collateral perfusion after radial artery harvesting remain unknown. To assess an optimal radial artery harvest technique for forearm circulation, we designed a prospective randomized trial. METHODS: Ninety patients were divided into 3 groups of 30 patients. Electrocautery, an ultrasonic scalpel, or sharp scissors and hemoclips were used to harvest radial arteries in groups 1, 2, and 3, respectively. The incidences of harvest site pain, numbness, swelling, discomfort, hematoma, and infection were compared. With forearm thermography, recovery times from cooled down 5 degrees back to rest temperature were compared between groups. All patients had postoperative forearm angiography at 1 and 12 months. RESULTS: Although there were no differences in the incidences of pain, swelling, and discomfort, the incidence of numbness was significantly lower in group 3 (P = .003). The temperature recovery time was significantly shorter in group 3 (P = .0009). On postoperative angiography at 1 month, the incidence of the development of interosseous arteries was significantly higher in group 3 (86.7%) than in groups 1 (23.3%) and 2 (36.7%). The 12-month study, however, showed that there was no difference among groups (73.3%, 80.0%, and 93.3% in groups 1, 2, and 3, respectively). CONCLUSIONS: These results suggest that sharp dissection with scissors and clips may be better for early postharvest forearm circulation and can decrease the incidence of hand numbness. However, there were no differences among the 3 methods with respect to forearm circulation 12 months after radial artery harvest.

Co-expression of parathyroid hormone and chromogranin A in secondary hyperparathyroidism: a functional marker for secretory activity of hyperplastic nodules.

The relationship between secretion of parathyroid hormone (PTH) and biologic characteristics, including cell proliferation or monoclonality, is not yet fully understood. To evaluate secretory activity of glands or nodules histopathologically, we focused on the co-expression of chromogranin A (CgA) and parathyroid hormone (PTH) in each gland or nodule. A total of 55 glands from 38 patients with normal parathyroid glands, hyperplastic glands (diffuse and nodular) and primary adenomas were compared. Co-expression of PTH and CgA was decreased to 44.4% in diffuse hyperplastic glands, and to 39.6% in 91 hyperplastic nodules, in contrast to normal glands and primary adenomas that showed constant co-expression of PTH and CgA. Immunohistochemical study of PTH showed a coarse granular pattern predominantly in PTH-positive/CgA-positive nodules, and a dot-like pattern mainly in PTH-positive/CgA-negative nodules. Laser scanning microscopy and immunoelectron microscopy confirmed that a dot-like pattern is based on a positive reaction of PTH at the Golgi apparatus. MIB-1 LI was 12.6 +/- 11.6 in PTH-positive/CgA-positive, and 19.3 +/- 27.3 in PTH-positive/CgA-negative nodules. In conclusion, a combination of PTH and CgA could provide more information about the physiologic state of secretory activity of each nodule than does the simple observation of PTH immunoreactivity.

[Investigation of CD68 positive monocytes/macrophage(CD68+ Mo/M phi) in urine and infiltrated tissue of various kidney diseases in children].

In order to investigate the participation of monocytes/macrophages(Mo/M phi) in the progression of various kidney diseases of children, Mo/M phi in urine and that infiltrating renal tissue were both measured as the number of CD68 positive Mo/M phi (CD68+ Mo/M phi), using anti-CD68 antibody. The number of CD68+ Mo/M phi infiltrating in one glomerulus was significantly higher in Henoch-Schönlein purpura nephritis(HSPN) (p < 0.01) in comparison with that in minimal change nephrotic syndrome(MCNS) (p < 0.01), and a high tendency was found in IgA nephropathy (IgAN), proliferative glomerulonephritis (non-IgAN), focal segmental glomerulosclerosis(FSGS) and membranoproliferative glomerulonephritis (MPGN), respectively. The number of CD68+ Mo/M phi infiltrating one mm2 of tubulo-interstitium area was significantly higher in HSPN(p < 0.05), FSGS(p < 0.01), Alport's syndrome(p < 0.01), respectively, than that in MCNS. The number of CD68+ Mo/M phi in one milliliter of urine correlated significantly with both that infiltrating the glomerulus and the tubulo-interstitium(both p < 0.01). Moreover the number of urine CD68+ Mo/M phi in a clinically active stage was significantly higher than that in an inactive stage in the AGN(p < 0.05), IgAN(p < 0.05), HSPN(p < 0.05), non-IgAN(p < 0.01) and MPGN groups(p < 0.05), respectively. From these results, 1) It was suggested that the Mo/M phi infiltrating renal tissue participated in the development of various kidney diseases. 2) It was predicted that CD68+ Mo/M phi in urine reflected both the number of Mo/M phi infiltrating the glomerulus and that in the tubulo-interstitium. 3) It was suggested that the number of CD68+ Mo/M phi in urine indicated clinical activity in proliferative glomerulonephritis groups of children.