Articular surface integrity assessed by ultrasound is associated with biological characteristics of articular cartilage in early-stage degeneration.

Early diagnosis of articular cartilage damage and repeated evaluation of treatment efficacy are essential for osteoarthritis treatment. In this study, we established a simple ultrasound grading system for early degenerative articular cartilage and investigated its relationship with cartilage biological characteristics. The ultrasound grading system were based on surface integrity (S1a: continuous high-echo lines, S1b: discontinuous or weak high-echo lines, S2: surface irregular) and cartilage echogenicity (E1: with > 50%, E2: < 50% hypoechoic area of total cartilage layer) and verified by surface roughness (Ra; µm) and histological staining. Ra was lower in S1 than in S2, and the percentage of hypoechoic and safranin O-stained areas was positively correlated. Then we examined its relationship with histopathological evaluation (OARSI grade), gene expression, and protein production in responded to pro-inflammatory cytokine (IL-1ß) stimulation. OARSI grades were different among S grades. The superficial layer of S1 had higher expression of Collagen10, aggrecan, Sox9, and lower expression of Collagen1 and BMP2 than that of S2. S1 responded more pronouncedly to IL-1ß in IL-6, IL-8, and CCL2 production than S2. There was no difference among the E-grades. Taken together, our findings indicate that ultrasound assessment using surface integrity can reflect the biological characteristics of early degenerative articular cartilage.

Meniscus surface texture is associated with degenerative changes in biological and biomechanical properties.

Meniscal degeneration is defined by semi-quantitative assessment of multiple histological findings and has been implicated in biomechanical dysfunction, yet little is known about its relationship with biological properties. This paper aimed to quantitatively evaluate degenerative findings in human meniscus to examine their relationship with gene expression and biomechanical properties, and to extract histological findings that reflect biological properties like gene expression and cytokine secretion. This study included lateral menisci of 29 patients who underwent total knee arthroplasty. The menisci were divided into six samples. For each sample, Pauli's histological evaluation and corresponding quantitative assessment (surface roughness, DNA content, collagen orientation, and GAG content) were performed, with surface roughness showing the highest correlation with the histological evaluation in a single correlation analysis (r = 0.66, p < 0.0001) and multivariate analysis (p < 0.0001). Furthermore, surface roughness was associated with gene expression related to meniscal degeneration and with tangent modulus which decreases with increasing degeneration (r = - 0.49, p = 0.0002). When meniscal tissue was classified by surface integrity, inflammatory cytokine secretion tended to be higher in severe degenerated menisci. These results suggest that the evaluation of meniscal surface texture could predict the degree of degeneration and inflammatory cytokine secretion.

Chronic Expanding Hematoma After Metal-on-Metal Total Hip Arthroplasty.

A 76-year-old woman who underwent bilateral metal-on-metal total hip arthroplasty fell 3 years after this procedure and subsequently incurred continuous pain in her buttock. Plain radiographs showed no fracture and no loosening of the hip prosthesis. Magnetic resonance imaging revealed an abnormal, large, thick-walled mass with heterogeneous signal intensity at the right buttock. The prerevision diagnosis was adverse reaction to metal debris. The mass was surgically resected, and the metal femoral head was replaced by a dual-mobility prosthesis. The intraoperative and histological analyses indicated an expanding hematoma. Cobalt ion concentrations of whole blood and effusion around the hematoma-1.9 µg/L and 1.3 µg/L, respectively-were not indicative of adverse reaction to metal debris. Transcatheter arterial embolization was performed 2 days postoperatively. The hematoma was reduced and was not present after 9 months. The diagnosis of a periprosthetic soft tissue mass after metal-on-metal total hip arthroplasty should be carefully reached with magnetic resonance imaging and assessment of blood metal ion concentrations. Expanding hematoma should be considered a potential diagnosis if metal ion concentrations are not increasing and magnetic resonance imaging shows a periprosthetic mass with a heterogeneous lesion. Embolization is useful for the management of an expanding hematoma. [Orthopedics. 2017; 40(6):e1103-e1106.].

Comparison between component designs with different femoral head size in metal-on-metal total hip arthroplasty; multicenter randomized prospective study.

BACKGROUNDS/AIMS: We prospectively studied 78 prostheses with conventional femoral head and 86 prostheses with large head (Magnum) of metal-on-metal total hip arthroplasty (MoM THA) with two years follow-up. METHODS: Clinical outcomes and blood metal ion were evaluated. RESULTS: There were no significant differences of clinical outcomes between groups. 1.17 ± 1.01 µg/L of blood cobalt ion in Magnum was significantly lower than 1.99 ± 2.34 µg/L in conventional group. No dislocation was observed in Magnum while one dislocation in conventional group. MoM THA with large head is useful if the implants are positioned in appropriate alignment, however longer follow-up will be necessary. CLINICAL TRIAL REGISTRATION: NCT01010763 (registered on ClinicalTrials.gov).

Are acetabular component alignment guides for total hip arthroplasty accurate?

The acetabular component orientation of total hip arthroplasty is of critical importance to the clinical results. Although navigation systems have recently been introduced, acetabular component alignment guides are still used in most of ordinary hospitals. However, the accuracy of alignment guides themselves has not been evaluated. Fifteen types of alignment guide were examined. In all the alignment guides, the angles actually indicated and those stated by manufacturers were different. Our results showed that usage of modern alignment guides inherently misleads anteversion into decrease by a mean of 6 degrees (maximum, 12 degrees ) and inclination into increase by a mean of 2 degrees (maximum: 4 degrees ). Such setting of alignment guides could be one of the factors of error in acetabular component orientation.

Clinical efficacy of mechanical thromboprophylaxis without anticoagulant drugs for elective hip surgery in an Asian population.

To evaluate the clinical efficacy of mechanical thromboprophylaxis after elective hip surgery, we reviewed 3016 patients who underwent hip surgery at 5 centers. Primary total hip arthroplasty (THA), revision THA, and pelvic or femoral osteotomies were performed in 2648, 298, and 70 patients, respectively. Epidural anesthesia, intraoperative calf bandage, early mobilization, and intermittent pneumatic compression postoperatively with additional use of elastic stockings were the basic regimen for thromboprophylaxis. Postoperatively, no cases of fatal pulmonary embolism (PE) were encountered. One symptomatic PE and 4 symptomatic deep vein thrombosis cases were identified, all of which were successfully treated using heparin and warfarin. By 6 months, no deaths had occurred. We conclude that mechanical thromboprophylaxis without anticoagulant drugs is safe and effective for elective hip surgeries in our patient population.

Comparison between highly cross-linked and conventional polyethylene in total knee arthroplasty.

The use of highly cross-linked polyethylene in total knee prostheses is still controversial. The aim of the present study was to compare radiographic and clinical results of using conventional and highly cross-linked polyethylene in cruciate retaining total knee prostheses of completely the same design. Two hundred and two consecutive total knee arthroplasties (NexGen CR, Zimmer) were performed using the same procedure. The first consecutive 113 knees had conventional polyethylene insert and following consecutive 89 knees had highly cross-linked polyethylene insert (Prolong, Zimmer). Differences in the age, gender, and diagnosis between two groups were not statistically significant. Preoperative range of motion (ROM) of the knee, and Knee Society Score (KSS) was better in highly cross-linked polyethylene group. Clinical and radiographic results were evaluated at two years after operation. The difference of ROM and KSS between groups was not statistically significant. There was no revision surgery. No knee exhibited osteolysis, aseptic loosening, or polyethylene failure. There was no early catastrophic clinical failure due to use of the new material.

Acetabular component orientation in intra- and postoperative positions in total hip arthroplasty.

INTRODUCTION: In total hip arthroplasty (THA), acetabular component orientation has critically important effects on dislocation, range of motion, polyethylene wear, pelvic osteolysis, and component migration. The differences in the pelvic orientation in the intraoperative lateral position for insertion of acetabular component during operation and that in the postoperative supine position for evaluation of acetabular component orientation will be one of the factors, which make outliers in acetabular component orientation. We compared acetabular component orientation between intraoperative lateral position and postoperative supine position in 100 consecutive primary THAs. MATERIALS AND METHODS: A total of 100 consecutive primary THAs (between October 2004 and December 2005) in 100 patients performed by a single surgical team were investigated. Intraoperative anteroposterior radiographs of pelvis in the lateral position and postoperative anteroposterior radiographs of pelvis in the supine position were taken. Acetabular component orientation (vertical tilt and anteversion) were measured using computer software. RESULTS: The absolute values of difference between measurements in the two positions were 5.3 degrees +/- 4.5 degrees (mean +/- SD) for vertical tilt and 5.1 degrees +/- 3.7 degrees for anteversion. The difference in the vertical tilt between the two positions was significant (P < 0.0001). CONCLUSION: The difference in the acetabular component orientation between the two positions, which might be caused by the difference between intra- and postoperative pelvic orientation, should be considered during THA.

Range of motion of standard and high-flexion cruciate retaining total knee prostheses.

Recently, use of high-flexion design was introduced in cruciate-retaining (CR) total knee prostheses. The purpose of this study was to prospectively compare the ranges of motion (ROMs) of 89 knees with standard and 87 knees with high-flexion CR total knee prostheses. Differences in age, gender, diagnosis, preoperative ROM of the knee, and Knee Society Score between the 2 groups were not statistically significant. At 12-month follow-up, average ROM was 112.0 degrees +/- 12.6 degrees for standard, and 115.3 degrees +/- 13.4 degrees for high-flexion CR prosthesis (P = .101). To our knowledge, this is the first report on the ROM with the high-flexion CR total knee prosthesis. Using the technique of anterior referencing for femoral component sizing and using a fixed 7 degrees slope for the tibial component, we found no significant differences between groups with regard to ROM, clinical, or radiographic parameters.

Wear particle analysis of highly crosslinked polyethylene isolated from a failed total hip arthroplasty.

Polyethylene wear particles are one of the most important factors affecting the results of total hip arthroplasty (THA). To reduce wear generation and to achieve better long-term results of THA, highly crosslinked polyethylene (HXPE) has recently been introduced and come into wide use. Thus far, however, there have been no reports on in vivo analysis of HXPE wear particles. We isolated HXPE wear particles from periprosthetic tissue of a failed THA and analyzed using scanning electron microscope. The number of particles was 5.33 x 10(7) g(-1). Particle size (equivalent circle diameter) was 0.66 +/- 0.40 microm (mean +/- standard error). Aspect ratio and roundness were 1.37 +/- 0.26 and 1.44 +/- 0.67, respectively. All the particles were round shaped, and "fibrils" or "shreds" were not detected. Thus far, this was the first report on in vivo wear particle analysis of HXPE. HXPE generated less, smaller, and rounder particles, compared with the corresponding reported values for particles generated from conventional polyethylene. These characteristics might affect macrophage response, osteolysis, and long-term results of THA with HXPE.

Flexion gap preparation opens the extension gap in posterior cruciate ligament-retaining TKA.

It has been reported that preparation of the flexion gap results in significant widening of the prepared extension gap in posterior stabilized (PS) total knee arthroplasty (TKA). To date, there is a paucity of data regarding cruciate ligament-retaining (CR) TKA. Changes in the extension gap caused by preparation of the flexion gap were measured in 42 varus osteoarthritic knees undergoing CR TKA. The extension gap was first prepared and then measured before and after preparation of the flexion gap. The extension gap increased significantly on both the medial and lateral sides (18.8-20.0 and 21.7-22.7 mm, respectively) (P < 0.01). Preparation of the flexion gap also resulted in significant widening of the extension gap on CR TKA. However, amount of extension gap increase in CR TKA was smaller than previous reports on PS TKA.