Distinct patterns of cytokines, chemokines, and growth factors in synovial fluid after ACL injury in comparison to osteoarthritis

This study analyzed knee synovial fluid after anterior cruciate ligament (ACL) tear and in osteoarthritis (OA) to test the hypotheses that concentrations of cytokines, chemokines, and growth factors differ (a) by diagnosis and (b) after ACL tear by time from injury and presence/absence of concomitant meniscus tear. Synovial fluid samples were collected from two groups, ACL tears (with or without meniscus tear) (N = 13) and Kellgren-Lawrence grade 3 and 4 OA (N = 16), undergoing clinically indicated aspiration of the knee joint. Multiple cytokines, chemokines, and growth factors were assessed using a multiplexed 45-protein panel. Comparisons were made for the concentrations of all molecules between ACL tear and OA patients, isolated versus combined ACL and meniscus tears, and categorized by time from injury: acute or early subacute (<15 days, N = 8) versus late subacute or chronic (>15 days and <3 months, N = 5). ACL tear patients have higher levels of six molecules (IL-4, IL-5, IL-13, PlGF-1, bNGF, TNF-α) in knee synovial fluid compared to OA patients. Isolated ACL tears express higher levels of IL-4, IL-13 and IFN-γ and lower levels of IL-7 than ACL tears with a concomitant meniscus tear. SDF-1α, PlGF-1, IL-1RA, HGF, bNGF, and BDNF levels are elevated immediately after injury and drop off significantly in the late subacute phase (after 15 days). Synovial fluid from knees with ACL tears have elevated metabolic activity compared to knees with OA. The cytokine profiles after ACL tears are influenced by the time from injury and the presence of meniscus tears. These findings offer valuable insights into the levels of cytokines, chemokines, and growth factors in the knee after ACL injury, information which may have important implications for the diagnosis, prognosis and treatment of this common pathology.

Patients' Characteristics Can Predict Clinical Outcomes Following Hip Arthroscopy by Reflecting the Patterns of Labral Tears: A Retrospective Observational Study

PURPOSE

To evaluate the relationship between morphological differences in labral tears and clinical features of the hip joint in patients who underwent hip arthroscopy.

MATERIALS AND METHODS

We retrospectively analyzed data from patients who underwent arthroscopic surgery for the treatment of labral tears. Hip labral tears were morphologically classified as longitudinal peripheral tears (group L), radial fibrillated tears (group FI), radial flaps (group FL), and an unstable labrum (group U). Radiographically, the center-edge angle, acetabular roof obliquity, vertical-center-anterior angle, alpha angle, femoral head-neck offset ratio, and crossover sign were evaluated and compared among the groups. The relationship between labral morphology and these radiographic findings, as well as clinical findings, such as age, gender, preoperative range of hip motion, and the clinical outcomes using modified Harris Hip Score (mHHS) were also examined.

RESULTS

This study included fifty patients. Groups L and FI were often observed in late middle-aged patients with relatively shallow acetabular coverage. Group FL tears were frequently observed in young males with radiographic features, such as femoroacetabular impingement (FAI), compared to the other groups. Group U comprised mostly young females with relatively shallow acetabular coverage compared to the other groups. For the postoperative mHHS, group FL showed the best score among all groups, with a significant difference between groups FL and FI (p = 0.034).

CONCLUSIONS

Our study revealed that morphologically, different labral tears were associated with different clinical features and radiological findings. Especially, our study can provide predictive findings for hip arthroscopists that younger males with FAI show better clinical outcomes when compared to middle-aged females with shallow acetabulum, which is indicative of degenerative hip labral tears.

LEVEL OF EVIDENCE

IV case series.

Posterior Ankle Arthroscopy for Flexor Hallucis Longus Entrapment: A Case Report

Introduction:

Stenosing tenosynovitis is a chronic disorder frequently observed in finger triggering of a digit. Regarding the toes, although entrapment of the flexor hallucis longus (FHL) has already been reported in a few cases among sports players, the clinical condition is uncommon. Besides, the case without any specific causes is particularly rare.

Case Report:

We report the case of a 26-year-old male with FHL entrapment. Even though he was unaware of any cause, he felt tenderness on the posteromedial side of his left ankle, and his great toe was locked in the flex position. Magnetic resonance imaging indicated effusion in the tendon sheath of the FHL and the possibility of a partial tear of the FHL. We hypothesized that the scar tissue secondary to the partial tear of the FHL may have been irritated at the retrotalar pulley below the sustentaculum tali, where the FHL glides. Therefore, posterior ankle arthroscopy was performed for the treatment of the FHL entrapment.

Conclusion:

Orthopedic surgeons should list this pathology as a differential diagnosis of posterior ankle pain, even in non-athletes.

A Novel Technique of Arthroscopic Ankle Lateral Ligament Repair Using a Knotless Suture Anchor

Background:

Although arthroscopic lateral ligament repair (ALLR) with suture anchors for chronic lateral ankle instability has become widely accepted, some complications have been reported as well. Establishment of a new technique is essential for better clinical outcomes after ALLR.

Purpose

To report a novel technique and good clinical results of ALLR using a knotless suture anchor.

Study Design:

Case series; Level of evidence, 4.

Methods:

We examined 30 patients (16 men and 14 women) who underwent ALLR. The mean age of the patients was 30.0 years, and the average period of postoperative monitoring was 21 months. The Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale was used for clinical evaluation postoperatively, and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) for patient-reported results. Surgical complications were also examined.

Results:

The JSSF ankle-hindfoot scale showed a significant improvement from preoperatively to follow-up (from 72.1 to 96.1; P < 0.001), and the SAFE-Q was significantly improved in all subscales (pain and pain-related, physical function and daily living, social function, shoe-related, and general health and well-being; P < 0.004 for all). Complications included residual joint pain due to remaining osteophytes in 1 case, scar pain of the accessory anterolateral portal in 2 cases, and positive Tinel sign indicative of superficial peroneal nerve irritation at the anterolateral portal in 1 case.

Conclusion:

The clinical results of the novel ALLR technique were overall satisfactory. Knot-related complications, one of the main reasons for postoperative complications, were reduced by using a knotless suture anchor.

Conventional computed tomography software can be used for accurate pre-operative templating in bipolar hip arthroplasty: A preliminary report

BACKGROUND

The aim of this study was to investigate the use of pre-operative templating for bipolar hip arthroplasty (BHA) for displaced femoral neck fracture using multiplanar reconstruction (MPR) of computed tomography (CT) images.

METHODS

Nineteen patients who underwent BHA were enrolled in this study. For pre- and post-operative evaluation, a CT scan was performed from the pelvis to the knee joints. MPR of the CT image was done using software to measure the femoral head cup diameter, offset, stem size, length of the modular neck, distance from the neck osteotomy, and femoral anteversion. We compared these parameters pre- and post-operatively.

RESULTS

Both the femoral head cup diameter and length of the modular neck were found to be significantly different between pre- and post-operative measurements, although the differences were minor. Other parameters, including the femoral offset, were not significantly different between the pre- and post-operative measurements. The size of the femoral stem, cup diameter, and length of the modular neck were consistent with the planned size and accurate (within ±1 size) in more than 84% cases.

CONCLUSION

Our pre-operative templating approach for BHA using MPR of CT has potential clinical utility as a complementary tool for pre-operative planning using three-dimensional templating software. Moreover, this technique could be feasible in most hospitals without additional expenditure.

Successful Transcatheter Arterial Embolisation for a Traumatic Iliacus Hematoma: A Case Report

A traumatic iliacus hematoma is rare and usually occurs in patients after a fall involving a lower back injury. Although the hematoma may compress the femoral nerve causing femoral nerve palsy, the gold standard treatment for this condition has not been established. Here we report transcatheter arterial embolisation as a useful treatment strategy for a traumatic iliacus hematoma.

Platelet-Rich Plasma Released From Polyethylene Glycol Hydrogels Exerts Beneficial Effects on Human Chondrocytes

Osteoarthritis (OA) is a debilitating joint disease resulting from chronic joint inflammation and erosion of articular cartilage. A promising biological treatment for OA is intra-articular administration of platelet-rich plasma (PRP). However, immediate bolus release of growth factors limits beneficial therapeutic effects of PRP, thus necessitating the demand for sustained release platforms. In this study, we evaluated the therapeutic value of PRP released from a polyethylene glycol (PEG) hydrogel on articular chondrocytes/cartilage explants derived from OA patients. Lyophilized PRP (PRGF) was encapsulated in PEG hydrogels at 10% w/v and hydrogel swelling, storage modulus and degradation and PRGF release kinetics were determined. PRGF releasate from the hydrogels was collected on day 1, 4, and 11. Encapsulation of PRGF at 10% w/v in PEG hydrogels had minimal effect on hydrogel properties. PRGF was released with an initial burst followed by sustained release until complete hydrogel degradation. Effect of PRGF releasates and bolus PRGF (1% w/v PRGF) on patient-derived cartilage explants or chondrocytes was assessed by chondrocyte proliferation (pico-green assay), gene expression for COL1A1, COL2A1, MMP13, COX2, and NFKB1 (real-time polymerase chain reaction), and measurement of nitric oxide concentration (Griess' assay). Compared to bolus PRGF, PRGF releasates enhanced chondrocyte proliferation, suppressed the expression of genes like MMP13, NFKB1, COL1A1, and COL2A1 and reduced levels of nitric oxide. Taken together, these results indicate that release of PRGF from PEG hydrogels may improve the therapeutic efficacy of PRP and merits further investigation in an animal model of OA. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2401-2410, 2019.

Does the duration to bipolar hip arthroplasty for femoral neck fracture influence on postoperative muscular strength?

BACKGROUND

The primary purpose of this study was to compare the postoperative muscular strength and functional performance between early versus late bipolar hip arthroplasty (BHA) intervention for femoral neck fracture classified by the duration from the onset to surgery.

METHODS

Twenty-one patients who could walk at 12 months or more after BHA were enrolled into this study. We examined the muscular strength of hip flexion, extension, abduction, and knee extension of these patients. Time of one-leg standing, timed up and go test, pain grade by visual analog scale, and Barthel index were also evaluated as functional indices. We classified these patients into two groups by the duration from the onset to surgery, namely: within 3 days until BHA (early OP) and more than 4 days (late OP) to compare these indices at the latest follow-up.

RESULTS

The mean days until operation were 2.3 days in the early-OP group and 5.9 days in the late-OP group, showing a significant difference between the two groups. Muscular strength and other functional indices were also found to have no significant differences between these two groups.

CONCLUSION

Our study suggests that the delay to operate might not severely compromise the muscular strength around the hip joint for least 1.5 years among ambulatory patients.

Clinical Outcomes of Total Ankle Arthroplasty With Total Talar Prosthesis

BACKGROUND

Total ankle arthroplasty (TAA) has been developed to treat patients with end-stage ankle osteoarthritis (OA). However, there is often difficulty in treating complicated pathologies such as ankle OA with subtalar joint OA and severe talar collapse. Therefore, this study aimed to explore the short-term results and complications of TAA with total talar prosthesis, known as combined TAA, as the new techniques to treat such complicated pathology.

METHODS

We examined postoperative results including ankle range of motion, Japanese Society for Surgery of the Foot (JSSF) scale, and complications. There were 22 patients (15 women), with mean follow-up of 34.9 (range, 24-53 months), and the mean age was 72 (range, 62-80) years. The main indications for combined TAA included osteoarthritis (18 patients), rheumatoid arthritis (3 patients), and talar osteonecrosis with osteoarthritis (one patient).

RESULTS

The mean range of motion improved from 4.0 to 14.4 degrees in dorsiflexion and from 23.8 to 32.0 degrees in plantarflexion. The JSSF scale improved from 50.5 to 91.5 points. Prolonged wound healing occurred in 3 patients, and medial malleolus fracture occurred in 4 patients.

CONCLUSION

Combined TAA was a reliable procedure for the treatment of not only ankle OA following avascular necrosis of talus but also of degeneration of both ankle and subtalar joints.

LEVEL OF EVIDENCE

Level IV, case series.

Denosumab Treatment Improved Health-Related Quality of Life in Osteoporosis: A Prospective Cohort Study

Improving patient health-related quality of life (HRQOL) and prevention of bone fracture are important components of the treatment of osteoporosis. Our aim in this study was to evaluate the effect of denosumab treatment in improving HRQOL among patients with osteoporosis. Our analysis was based on 332 patients with osteoporosis, followed for 24 months. All patients received denosumab (60 mg) subcutaneously every 6 months. Bone mineral density (BMD) was assessed at the distal radius, with serum concentration of calcium, phosphate, P1NP, and TRACP5b also measured. HRQOL assessment included pain (visual analogue scale [VAS]) and the EQ-5D questionnaire. A multivariate analysis was performed to identify the possible confounders associated with deterioration in the EQ-5D utility score in response to denosumab treatment. Denosumab treatment yielded a 3.4% increase in BMD at 24 months. Serum levels of TRACP5b and P1NP decreased significantly, from baseline, at 6 months, with no effect on calcium and phosphate levels. Pain VAS and EQ-5D utility score improved significantly, from baseline, at 6 months, with the EQ-5D utility score correlating with the BMD at all time points of measurement over the 24-month period of observation. Knee osteoarthritis and multiple comorbidities were significantly associated with a worse HRQOL in response to denosumab treatment. Denosumab treatment increased BMD, with improvements in BMD correlating with improved HRQOL, supporting a possible benefit of using denosumab for the treatment of osteoporosis. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Evidence for Genetic Contribution to Variation in Posttraumatic Osteoarthritis in Mice

OBJECTIVE

Recombinant inbred mouse strains generated from an LG/J and SM/J intercross offer a unique resource to study complex genetic traits such as osteoarthritis (OA). We undertook this study to determine the susceptibility of 14 strains to various phenotypes characteristic of posttraumatic OA. We hypothesized that phenotypic variability is associated with genetic variability.

METHODS

Ten-week-old male mice underwent surgical destabilization of the medial meniscus (DMM) to induce posttraumatic OA. Mice were killed 8 weeks after surgery, and knee joints were processed for histology to score cartilage degeneration and synovitis. Micro-computed tomography was used to analyze trabecular bone parameters including subchondral bone plate thickness and synovial ectopic calcifications. Gene expression in the knees was assessed using a QuantiGene Plex assay.

RESULTS

Broad-sense heritability ranged from 0.18 to 0.58, which suggested that the responses to surgery were moderately heritable. The LGXSM-33, LGXSM-5, LGXSM-46, and SM/J strains were highly susceptible to OA, while the LGXSM-131b, LGXSM-163, LGXSM-35, LGXSM-128a, LGXSM-6, and LG/J strains were relatively OA resistant. This study was the first to accomplish measurement of genetic correlations of phenotypes that are characteristic of posttraumatic OA. Cartilage degeneration was significantly positively associated with synovitis (r = 0.83-0.92), and subchondral bone plate thickness was negatively correlated with ectopic calcifications (r = -0.59). Moreover, we showed that 40 of the 78 genes tested were significantly correlated with various OA phenotypes. However, unlike the OA phenotypes, there was no evidence for genetic variation in differences in gene expression levels between DMM-operated and sham-operated knees.

CONCLUSION

For these mouse strains, various characteristics of posttraumatic OA varied with genetic composition, which demonstrated a genetic basis for susceptibility to posttraumatic OA. The heritability of posttraumatic OA was established. Phenotypes exhibited various degrees of correlations; cartilage degeneration was positively correlated with synovitis, but not with the formation of ectopic calcifications. Further investigation of the genome regions that contain genes implicated in OA, as well as further investigation of gene expression data, will be useful for studying mechanisms of OA and identifying therapeutic targets.

Downregulation of aquaporin 9 decreases catabolic factor expression through nuclear factor‑κB signaling in chondrocytes

Aquaporins (AQPs) are small integral membrane proteins that are essential for water transport across membranes. AQP9, one of the 13 mammalian AQPs (including AQP0 to 12), has been reported to be highly expressed in hydrarthrosis and synovitis patients. Given that several studies have identified signal transduction as an additional function of AQPs, it is hypothesized that AQP9 may modulate inflammatory signal transduction in chondrocytes. Therefore, the present study used a model of interleukin (IL)‑1β‑induced inflammation to determine the mechanisms associated with AQP9 functions in chondrocytes. Osteoarthritis (OA) and normal cartilage samples were subjected to immunohistological analysis. In addition, matrix metalloproteinase (MMP)3, MMP13 and a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS‑5) mRNA and protein analysis was conducted in normal human articular chondrocytes from the knee (NHAC‑Kn) stimulated with IL‑1β by reverse transcription‑polymerase chain reaction (RT‑qPCR) and western blotting, respectively. AQP9 knockdown was also performed by transfection of AQP9‑specific small interfering RNA using Lipofectamine. AQP1, 3, 7, 9 and 11 mRNA expression levels were detected in OA human chondrocytes and in IL‑1β‑treated normal human chondrocytes. The levels of AQP9, MMP‑3, MMP‑13 and ADAMTS‑5 mRNA were increased by treatment with 10 ng/ml IL‑1β in a time‑dependent manner, while knockdown of AQP9 expression significantly decreased the mRNA levels of the MMP3, MMP13 and ADAMTS‑5 genes, as well as the phosphorylation of IκB kinase (IKK). Treatment with a specific IKK inhibitor also significantly decreased the expression levels of MMP‑3, MMP‑13 and ADAMTS‑5 in response to IL‑1β stimulation. Furthermore, immunohistochemical analysis demonstrated that AQP9 and inflammatory markers were highly expressed in OA cartilage. In addition, the downregulation of AQP9 in cultured chondrocytes decreased the catabolic gene expression in response to IL‑1β stimulation through nuclear factor‑κB signaling. Therefore, AQP9 may be a promising target for the treatment of OA.

Molecular influence of anterior cruciate ligament tear remnants on chondrocytes: a biologic connection between injury and osteoarthritis

OBJECTIVE

Anterior cruciate ligament (ACL) injury initiates a cascade of events often leading to osteoarthritis (OA). ACL reconstruction does not alter the course of OA, suggesting that heightened OA risk is likely due to factors in addition to the joint instability. We showed that torn ACL remnants express periostin (POSTN) in the acute phase of injury. Considering that ACL injury predisposes to OA and that POSTN is associated with cartilage metabolism, we hypothesize that ACL injury affects chondrocytes via POSTN.

DESIGN

Cartilage was obtained from osteoarthritic patients and ACL remnants were collected from patients undergoing ACL reconstruction. Crosstalk between ACL remnants and chondrocytes was studied in a transwell co-culture system. Expression of POSTN and other anabolic and catabolic genes was assessed via real-time polymerase chain reaction (PCR). Immunostaining for periostin was performed in human and mouse cartilage. The impact of exogenous periostin and siRNA-mediated ablation of periostin on matrix metabolism and cell migration was examined. Furthermore, the effect of anabolic (transforming growth factor beta 1 [TGF-β1]) and catabolic (interleukin 1 beta [IL-1β]) factors on POSTN expression was investigated.

RESULTS

ACL remnants induced expression of POSTN, MMP13 and ADAMTS4. Periostin levels were significantly higher in osteoarthritic compared to normal cartilage. Exogenous periostin induced MMP13 expression and cell migration, and repressed COL1A1 expression while POSTN knockdown inhibited expression of both anabolic and catabolic genes and impeded cell migration. TGF-β1 and IL-1β treatment did not alter POSTN expression but influenced chondrocyte metabolism as determined by quantification of anabolic and catabolic genes via real-time PCR.

CONCLUSIONS

ACL remnants can exert paracrine effects on cartilage, altering cellular homeostasis. Over time, this metabolic imbalance could contribute to OA development.

Depletion of aquaporin 1 decreased ADAMTS‑4 expression in human chondrocytes

Inflammation serves an important role in the progression of osteoarthritis (OA), and IL-1β may act as a catabolic factor on cartilage, reducing the synthesis of primary cartilage components type II collagen and aggrecan. Aquaporin 1 (AQP1) is a 28-kDa water channel formed of six transmembrane domains on the cell membrane. AQP1 is highly expressed in the anus, gallbladder and liver, and is moderately expressed in the hippocampus, ependymal cells of the central nervous system and articular cartilage. It was hypothesized that AQP1 may be highly expressed in OA cartilage and that it may increase the expression of catabolic factors during inflammatory OA progression. Therefore, the present study evaluated AQP1 functions in human OA articular chondrocytes. Primary chondrocytes were isolated from human hip and knee cartilage tissues, cultured and transfected with AQP1-specific small interfering RNA with or without subsequent IL-1β treatment. In vitro explant culture from hip cartilages were also prepared. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to assess the expression of AQP genes in human articular cartilage, AQP1 immunohistochemistry of the cartilages and explant culture, as well as RT-quantitative PCR, western blotting and immunocytochemistry/immunofluorescence of OA chondrocytes to evaluate the expression of AQP1, and catabolic and anabolic factors. RT-PCR results demonstrated that AQP0, 1, 3, 7, 9, and 11 were expressed in OA chondrocytes. Immunohistochemistry revealed that AQP1 was highly expressed in the superficial to middle zones of OA articular cartilages. Additionally, AQP1 mRNA was significantly higher in OA cartilage and IL-1β treatment significantly increased AQP1 expression in hip explant cartilage. Furthermore, AQP1 downregulation decreased a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-4 expression in OA chondrocytes, though it did not affect other associated genes. Immunofluorescence showed that AQP1 and ADAMTS-4 were co-localized. These findings indicated that AQP1 depletion may decrease ADAMTS-4 expression in human OA chondrocytes. Therefore, regulating AQP1 expression may be a strategy to suppress catabolic factors during OA progression.

Consecutive Bilateral Hip Arthroscopy for Symptomatic Bilateral Femoroacetabular Impingement in an Elite Rugby player: A Case Report

We report a case of concurrent bilateral hip arthroscopy for symptomatic bilateral femoroacetabular impingement (FAI) performed under the single anesthesia on an elite rugby player. A 27-year-old rugby player who played for a top league had bilateral hip joint pain. Physical examination revealed bilateral tenderness in the anterior area of the hips, with positive impingement signs. Based on the findings of hip radiography and magnetic resonance imaging, the patient's symptoms were diagnosed as bilateral FAI with hip labral tears. Bilateral hip arthroscopy under the single anesthesia was performed due to refractory symptoms. He returned to regular rugby games without any symptoms in either hip. Bilateral hip arthroscopic surgery under the single anesthesia should be an effective treatment for typical and symptomatic FAI, even in elite athletes.

Arthroscopic Debridement of a Talar Cyst and Bone Grafting with the Osteochondral Autograft Transfer System A Case Report

Simple bone cysts compose approximately 3% of all primary bone tumors and most commonly occur in the metaphyseal regions of the proximal humerus and femur. The percentage of the talus with suspected bone tumors is reported to be 0.003%. Therefore, talar cysts are rare but sometimes present as aggressive lesions, and they can affect any of the tarsal bones. Recently, an arthroscopic approach to these lesions has been developed that is less invasive than conventional open surgery. In the present case study, we profile a 65-year-old female patient who received arthroscopic debridement of a bone cyst from the medial aspect of the talus with the osteochondral autograft transfer system (OATS). By using the OATS core harvester, we penetrated into the tumor. After the cylindrical bone plug was pulled out, the tumor was removed and artificial bone granules were firmly packed into the cavity with intralesional arthroscopy. Then, the cylindrical bone plug previously harvested by OATS was implanted at the site with careful precision. This intervention resulted in a relative restoration of talar dome anatomy and ultimately restored the patient to activity with minimal discomfort. Therefore, arthroscopic debridement with OATS has the potential to be a useful option in dealing with debilitating osteochondral cystic lesions.

Cyclin-Dependent Kinase Inhibitor-1-Deficient Mice are Susceptible to Osteoarthritis Associated with Enhanced Inflammation

Osteoarthritis (OA) is a multifactorial disease, and recent data suggested that cell cycle-related proteins play a role in OA pathology. Cyclin-dependent kinase (CDK) inhibitor 1 (p21) regulates activation of other CDKs, and recently, we reported that p21 deficiency induced susceptibility to OA induced by destabilization of the medial meniscus (DMM) surgery through STAT3-signaling activation. However, the mechanisms associated with why p21 deficiency led to susceptibility to OA by the STAT3 pathway remain unknown. Therefore, we focused on joint inflammation to determine the mechanisms associated with p21 function during in vitro and in vivo OA progression. p21-knockout (p21^-/- ) mice were used to develop an in vivo OA model, and C57BL/6 (p21^+/+ ) mice with the same background as the p21^-/- mice were used as controls. Morphogenic changes were measured using micro-CT, IL-1β serum levels were detected by ELISA, and histological or immunohistological analyses were performed. Our results indicated that p21-deficient DMM-model mice exhibited significant subchondral bone destruction and cartilage degradation compared with wild-type mice. Immunohistochemistry results revealed p21^-/- mice susceptibility to OA changes accompanied by macrophage infiltration and enhanced MMP-3 and MMP-13 expression through IL-1β-induced NF-κB signaling. p21^-/- mice also showed subchondral bone destruction according to micro-CT analysis, and cathepsin K staining revealed increased numbers of osteoclasts. Furthermore, p21^-/- mice displayed increased serum IL-1β levels, and isolated chondrocytes from p21^-/- mice indicated elevated MMP-3 and MMP-13 expression with phosphorylation of IκB kinase complex in response to IL-1β stimulation, whereas treatment with a specific p-IκB kinase inhibitor attenuated MMP-3 and MMP-13 expression. Our results indicated that p21-deficient DMM mice were susceptible to alterations in OA phenotype, including enhanced osteoclast expression, macrophage infiltration, and MMP expression through IL-1β-induced NF-κB signaling, suggesting that p21 regulation may constitute a possible therapeutic strategy for OA treatment. © 2017 American Society for Bone and Mineral Research.

Therapeutic efficacy of intra-articular hyaluronan derivative and platelet-rich plasma in mice following axial tibial loading

Objective

To investigate the therapeutic potential of intra-articular hyaluronan-derivative HYADD^® 4-G and/or platelet-rich plasma (PRP) in a mouse model of non-invasive joint injury.

Methods

Non-invasive axial tibial loading was used to induce joint injury in 10-week-old C57BL/6J mice (n = 86). Mice underwent a single loading of either 6 Newton (N) or 9N axial tibial compression. HYADD^® 4-G was injected intra-articularly at 8 mg/mL or 15 mg/mL either before or after loading with or without PRP. Phosphate-buffered-saline was injected as control. Knee joints were harvested at 5 or 56 days post-loading and prepared for micro-computed tomography scanning and subsequently processed for histology. Immunostaining was performed for aggrecan to monitor its distribution, for CD44 to monitor chondrocyte reactive changes and for COMP (cartilage oligomeric matrix protein) as an index for cartilage matrix changes related to loading and cartilage injury. TUNEL assay was performed to identify chondrocyte apoptosis.

Results

Loading initiated cartilage proteoglycan loss and chondrocyte apoptosis within 5 days with slowly progressive post-traumatic osteoarthritis (no cartilage degeneration, but increased synovitis and ectopic calcification after 9N loading) at 56 days. Mice treated with repeated HYADD^® 4-G (15 mg/mL) or HYADD^® 4-G (8 mg/mL) ± PRP or PRP alone exhibited no significant improvement in the short-term (5 days) and long-term (56 days) consequences of joint loading except for a trend for improved bone changes compared to non-loaded joints.

Conclusion

While we failed to show an overall effect of intra-articular delivery of hyaluronan-derivative and/or PRP in reversing/protecting the pathological events in cartilage and synovium following joint injury, some bone alterations were relatively less severe with hyaluronan-derivative at higher concentration or in association with PRP.

Surgical management of the peroneus quartus muscle for bilateral ankle pain: a case report

The peroneus quartus muscle is an accessory muscle seen in the lateral compartment of the lower leg. Although the peroneus quartus muscle is asymptomatic in general, it sometimes becomes pathologic. We present the rare case of bilateral ankle pain with crepitation caused by the peroneus quartus muscle. Magnetic resonance imaging should be considered to assist with diagnosing this condition. Foot and ankle surgeons should consider it in the preoperative differential diagnosis when patients present with posterior ankle pain.

Surgical Management of Irreducible Dislocation of the Peroneus Longus Tendon A Case Report

Peroneal tendon dislocation is often overlooked because the mechanism of injury is similar to that of lateral ligament sprains and the frequency of the disease is low. Therefore, it is difficult to treat peroneal tendon dislocation when diagnosed in the chronic state. Furthermore, because irreducible peroneal tendon dislocation has multiple causes, treatment is much harder. Herein, we present a rare case of irreducible dislocation caused by a complex pathogenesis. Surgical treatment yielded good results. Orthopedic surgeons should be aware of this issue and consider it in the preoperative simulation.

Inflammation and Degeneration in Cartilage Samples from Patients with Femoroacetabular Impingement

BACKGROUND

Femoroacetabular impingement (FAI) has been reported as a cause of hip pain in young patients and is suggested as the trigger for hip osteoarthritis (OA). The goal of this study was to quantify the metabolic profiles of articular tissues (cartilage, synovium, and labrum) harvested from patients with FAI and with end-stage OA. In addition, we sought to investigate the development of secondary OA in hips with FAI.

METHODS

Tissue samples were obtained from thirty hips undergoing arthroscopic surgery for FAI with or without labral tear and thirty hips undergoing total hip arthroplasty for OA. Quantitative real-time polymerase chain reaction (PCR) was performed to determine the gene expression of inflammatory cytokines and metabolic (anabolic and catabolic) enzymes. The differences in gene expression in articular tissues from the patients with FAI were also evaluated on the basis of clinical parameters (age range and alpha angle).

RESULTS

The messenger RNA (mRNA) expression of the inflammatory cytokines interleukin-1 beta (IL-1β) and IL-8 and of matrix metalloproteinase (MMP)-3 (a catabolic gene) in both the synovium and the labrum, and the expression of collagen type I alpha 1 (an anabolic gene) in the labrum, was higher in the samples from hips with OA than in those from hips with FAI (p < 0.05). In cartilage, however, the mRNA expression of the inflammatory cytokines and the catabolic genes MMP-13 and ADAMTS-4 (a disintegrin and metalloproteinase with thrombospondin motifs-4) was higher in the FAI samples compared with the OA samples (p < 0.01). When the expression of inflammatory cytokines was evaluated among the three types of tissues within each disease group, the expression levels were the highest in cartilage within the FAI samples (p < 0.01). In FAI cartilage, we found higher gene expression of aggrecan (ACAN) and ADAMTS-4 in the samples from patients with larger alpha angles (≥60°) (p < 0.01).

CONCLUSIONS

Our results indicate that the metabolic conditions of articular cartilage in FAI and OA are different and that the expression of genes associated with inflammation is greater in the articular cartilage of patients with FAI compared with the synovium and the labrum. The metabolic changes were heightened by mechanical impingement.

CLINICAL RELEVANCE

The articular cartilage from the impingement lesion in patients with FAI showed biologically higher inflammation and degeneration, supporting the concept that FAI may be a trigger for joint degeneration.

p21 deficiency is susceptible to osteoarthritis through STAT3 phosphorylation

Introduction

Osteoarthritis (OA) is a multifactorial disease, and recent studies have suggested that cell cycle–related proteins play a role in OA pathology. p21 was initially identified as a potent inhibitor of cell cycle progression. However, it has been proposed that p21 is a regulator of transcription factor activity. In this study, we evaluated the role of p21 in response to biomechanical stress.

Methods

Human chondrocytes were treated with p21-specific small interfering RNA (siRNA), and cyclic tensile strain was introduced in the presence or absence of a signal transducer and activator of transcription 3 (STAT3)-specific inhibitor. Further, we developed an in vivo OA model in a p21-knockout background for in vivo experiments.

Results

The expression of matrix metalloproteinase (MMP13) mRNA increased in response to cyclic tensile strain following transfection with p21 siRNA, whereas the expression of aggrecan was decreased. Phospho-STAT3 and MMP-13 protein levels increased following downregulation of p21, and this was reversed by treatment with a STAT3 inhibitor. p21-deficient mice were susceptible to OA, and this was associated with increased STAT3 phosphorylation, elevated MMP-13 expression, and elevation of synovial inflammation. The expression of p21 mRNA was decreased and phosphorylation of STAT3 was elevated in human OA chondrocytes.

Conclusions

The lack of p21 has catabolic effects by regulation of aggrecan and MMP-13 expression through STAT3 phosphorylation in the cartilage tissue. p21 may function as a regulator of transcriptional factors other than the inhibitor of cell cycle progression in the cartilage tissue. Thus, the regulation of p21 may be a therapeutic strategy for the treatment of OA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0828-6) contains supplementary material, which is available to authorized users.

Comparison of the Sliding and Femoral Head Rotation among Three Different Femoral Head Fixation Devices for Trochanteric Fractures

Background

Recently, various femoral head fixation devices (HFDs) for trochanteric fractures have become available. However, there are some cases in which femoral head rotation with excessive sliding of the HFD is observed and it is often followed by cutout. The purpose of this study is to compare the ability of the three types of HFDs to prevent femoral head rotation.

Methods

Between July 2005 and December 2009, 206 patients aged over 60 years with trochanteric fractures who had undergone surgical treatment using a short femoral nail in our institution were enrolled into the study. We used the gamma 3 nail (GMN) as the screw-type HFD in 66 cases, the gliding nail (GLN) as a non-cylindrical blade in 76 cases, and the proximal femoral nail antirotation (PFNA) as a cylindrical blade in 64 cases. The sliding length of HFDs and the occurrence of femoral head rotation were evaluated by assessing radiographs as the main outcome, and the results were compared among these devices.

Results

A comparison of the degree of sliding in the GMN group showed that femoral head rotation was observed significantly more frequently in cases with rotation. Further, it appeared that femoral head rotation occurred more frequently in comminuted fractures. However, no significant differences between the sliding lengths of the different HFDs were observed among three groups. Femoral head rotation was observed in 15 cases of GMN (22.7%), 0 case of GLN, and 5 case of PFNA (7.8%). Significant differences with regard to the occurrence of femoral head rotation were observed among the three groups. Furthermore, significant differences were also observed between GLN and PFNA with respect to the occurrence of femoral head rotation.

Conclusions

The ability to stabilize femoral head appears to be greater with blade-type materials than with screw-type materials. Furthermore, we believe that a non-cylindrical blade is preferable to a cylindrical blade for the surgical treatment of comminuted, unstable trochanteric fractures in order to prevent femoral head rotation and cut-out.

Accurate and Easy Measurement of Sliding Distance of Intramedullary Nail in Trochanteric Fracture

Background

In daily clinical practice, it is essential to properly evaluate the postoperative sliding distance of various femoral head fixation devices (HFD) for trochanteric fractures. Although it is necessary to develop an accurate and reproducible method that is unaffected by inconsistent postoperative limb position on radiography, few studies have examined which method is optimal. Therefore, the purpose of this study is to prospectively compare the accuracy and reproducibility of our four original methods in the measurement of sliding distance of the HFD.

Methods

Radiographs of plastic simulated bone implanted with Japanese proximal femoral nail antirotation were taken in five limb postures: neutral, flexion, minute internal rotation, greater external rotation, and flexion with external rotation. Orthopedic surgeons performed five measurements of the sliding distance of the HFD in each of the flowing four methods: nail axis reference (NAR), modified NAR, inner edge reference, and nail tip reference. We also assessed two clinical cases by using these methods and evaluated the intraclass correlation coefficients.

Results

The measured values were consistent in the NAR method regardless of limb posture, with an even smaller error when using the modified NAR method. The standard deviation (SD) was high in the nail tip reference method and extremely low in the modified NAR method. In the two clinical cases, the SD was the lowest in the modified NAR method, similar to the results using plastic simulated bone. The intraclass correlation coefficients showed the highest value in the modified NAR method.

Conclusions

We conclude that the modified NAR method should be the most recommended based on its accuracy, reproducibility, and usefulness.

P21 deficiency delays regeneration of skeletal muscular tissue

The potential relationship between cell cycle checkpoint control and tissue regeneration has been indicated. Despite considerable research being focused on the relationship between p21 and myogenesis, p21 function in skeletal muscle regeneration remains unclear. To clarify this, muscle injury model was recreated by intramuscular injection of bupivacaine hydrochloride in the soleus of p21 knockout (KO) mice and wild type (WT) mice. The mice were sacrificed at 3, 14, and 28 days post-operation. The results of hematoxylin-eosin staining and immunofluorescence of muscle membrane indicated that muscle regeneration was delayed in p21 KO mice. Cyclin D1 mRNA expression and both Ki-67 and PCNA immunohistochemistry suggested that p21 deficiency increased cell cycle and muscle cell proliferation. F4/80 immunohistochemistry also suggested the increase of immune response in p21 KO mice. On the other hand, both the mRNA expression and western blot analysis of MyoD, myogenin, and Pax7 indicated that muscular differentiation was delayed in p21KO mice. Considering these results, we confirmed that muscle injury causes an increase in cell proliferation. However, muscle differentiation in p21 KO mice was inhibited due to the low expression of muscular synthesis genes, leading to a delay in the muscular regeneration. Thus, we conclude that p21 plays an important role in the in vivo healing process in muscular injury.

Oxidative stress-induced apoptosis and matrix loss of chondrocytes is inhibited by eicosapentaenoic acid

Eicosapentaenoic acid (EPA) is an antioxidant and n-3 polyunsaturated fatty acid that reduces the production of inflammatory cytokines. We evaluated the role of EPA in chondrocyte apoptosis and degeneration. Normal human chondrocytes were treated with EPA and sodium nitroprusside (SNP). Expression of metalloproteinases (MMPs) was detected by real-time polymerase chain reaction (PCR) and that of apoptosis-related proteins was detected by western blotting. Chondrocyte apoptosis was detected by flow cytometry. C57BL/6J mice were used for the detection of MMP expression by immunohistochemistry and for investigation of chondrocyte apoptosis. EPA inhibited SNP-induced chondrocyte apoptosis, caspase 3 and poly(ADP-ribose) polymerase cleavage, phosphorylation of p38 MAPK and p53, and expression of MMP3 and MMP13. Intra-articular injection of EPA prevented the progression of osteoarthritis (OA) by inhibiting MMP13 expression and chondrocyte apoptosis. EPA treatment can control oxidative stress-induced OA progression, and thus may be a new approach for OA therapy.

Cyclin‑dependent kinase inhibitor p21 does not impact embryonic endochondral ossification in mice

Endochondral ossification at the growth plate is regulated by a number of factors and hormones. The cyclin-dependent kinase inhibitor p21 has been identified as a cell cycle regulator and its expression has been reported to be essential for endochondral ossification in vitro. However, to the best of our knowledge, the function of p21 in endochondral ossification has not been evaluated in vivo. Therefore, the aim of this study was to investigate the function of p21 in embryonic endochondral ossification in vivo. Wild-type (WT) and p21 knockout (KO) pregnant heterozygous mice were sacrificed on embryonic days E13.5, E15.5 and E18.5. Sagittal histological sections of the forearms of the embryos were collected and stained with Safranin O and 5-bromo-2′-deoxyuridine (BrdU). Additionally, the expression levels of cyclin D1, type II collagen, type X collagen, Sox9, and p16 were examined using immunohistochemistry, and the expression levels of p27 were examined using immunofluorescence. Safranin O staining revealed no structural change between the cartilage tissues of the WT and p21KO mice at any time point. Type II collagen was expressed ubiquitously, while type X collagen was only expressed in the hypertrophic zone of the cartilage tissues. No differences in the levels of Sox9 expression were observed between the two groups at any time point. The levels of cyclin D1 expression and BrdU uptake were higher in the E13.5 cartilage tissue compared with those observed in the embryonic cartilage tissue at subsequent time points. Expression of p16 and p27 was ubiquitous throughout the tissue sections. These results indicate that p21 may not be essential for embryonic endochondral ossification in articular cartilage of mice and that other signaling networks may compensate for p21 deletion.

Tibial tubercle osteotomy with screw fixation for total knee arthroplasty

This study investigated the efficacy of tibial tubercle osteotomy (TTO) with screw fixation as part of the surgical treatment of primary complicated total knee arthroplasty (TKA) and revision TKA. From January 2000 to April 2011, 15 patients (15 knees) underwent revision TKA and 20 patients (21 knees) underwent primary TKA. The average patient age was 68.7±8.7 years. Patients underwent follow-up at the authors' institution for an average of 60.6±32.9 months. Comparison of preoperative and postoperative Knee Society Scores and Knee Society Functional Scores showed significant postoperative improvement (P<.05). Moreover, postoperative range of motion of the knee improved from 88.5°±33.8° to 104.3°±18.2° (P<.05). Radiographic assessment showed that the average period to bone union was 10.8±5 weeks (range, 5-28 weeks), the average length of the bone fragment was 59.4±5.9 mm, the average width at the proximal end was 18.9±2.9 mm, and the average thickness at the proximal end of the osteotomy was 10.3±1.2 mm. Tibial tubercle osteotomy provided wide exposure for TKA while protecting the extensor mechanism. Solid bone-to-bone fixation was achieved using TTO with 2 screws, and although the overall complication rate was 8.3%, none of the complications were associated with TTO itself. It is recommended that the bone fragment be 60 mm long, 20 mm wide, and 10 mm thick at the proximal end. Appropriate size of the osteotomized bone and solid screw fixation are essential to prevent complications during this procedure.

Satisfactory results at 8 years mean follow-up after ADVANCE® medial-pivot total knee arthroplasty

BACKGROUND

Although good overall results have been reported with TKA, certain problems and limitations remain, primarily due to postoperative differences in joint kinematics, when compared with the normal knee. ADVANCE® Medial-Pivot TKA involves replicating the medial pivoting behavior observed in normal knees. Here, we aimed to investigate the clinical and radiological results and complications of TKA using this implant, at mid-term follow-up.

METHODS

From January 2001 to March 2012, we retrospectively selected 76 patients (85 knees; mean age at operation, 70.2±8.1 years; range, 51-88 years) with a mean follow-up period of 93.1±14.3 months (range, 72-132 months). Indications for TKA included primary degenerative osteoarthritis (60 knees), rheumatoid arthritis (22 knees), osteonecrosis (two knees), and osteoarthritis following high tibial osteotomy (one knee). The clinical and radiographic results were evaluated.

RESULTS

Kaplan-Meier survivorship analysis indicated a success rate of 98.3% (95% confidence interval, 96.6-99.9%). Comparison of pre- and postoperative knee extension angles and ranges of motion showed significant improvement postoperatively, in both the Knee Society Scores (KSS) and Knee Society Functional Scores (KSFS) (p<0.05). In one case, radiographic assessment indicated implant loosening due to infection; however, despite this complication, significant improvement of postoperative varus or valgus deformity angles were noted in all cases (p<0.05).

CONCLUSION

Patients undergoing ADVANCE® Medial-Pivot TKA achieved excellent clinical and radiographic results without any implant-related failures at mid-term follow-up.

LEVEL OF EVIDENCE

Level IV.

PTEN regulates matrix synthesis in adult human chondrocytes under oxidative stress

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was identified as an important tumor suppressor gene. PTEN functions as a negative regulator of phosphoinositol-3-kinase (PI3K)-Akt and MEK/ERK signaling. The PI3K-Akt pathway is critical for cell survival, differentiation, and matrix synthesis. Oxidative stress is considered a critical factor in the onset and progression of osteoarthritis (OA). Therefore, we investigated the function of PTEN in OA chondrocytes under oxidative stress. Chondrocytes were treated with insulin-like growth factor-1 (IGF-1) and/or tert-butyl hydroperoxide (tBHP), which causes oxidative stress. The expression levels of type2 collagen (Col2a1) and aggrecan were analyzed by real-time PCR, and phosphorylation of Akt and ERK1/2 was analyzed by Western blotting. Chondrocytes were treated with PTEN-specific small interfering RNA (siRNA), as well as IGF-1 and/or tBHP. PTEN and IGF-1 expressions in OA chondrocytes were increased. The downregulation of PTEN expression increased the expression levels of Col2a1 and aggrecan, and increased proteoglycan synthesis under oxidative stress. Oxidative stress decreased the phosphorylation of Akt and increased that of ERK1/2. The downregulation of PTEN expression increased Akt phosphorylation, but did not increase that of ERK 1/2. Our results suggest that PTEN regulates matrix synthesis via the PI3K-Akt pathway under oxidative stress.

Evaluation of patellofemoral joint in ADVANCE Medial-pivot total knee arthroplasty

PURPOSE

ADVANCE Medial Pivot (MP) (Wright Medical) total knee arthroplasty (TKA) was established to replicate normal tibio-femoral knee joint kinematics, however, its influence on the patello-femoral (PF) joint is unclear. The purpose in this study was to assess the PF joint conditions in Advance MP TKA, via radiography and three-dimensional image-matching software.

METHODS

Ten subjects with osteoarthritis were treated with the ADVANCE MP TKA. Pre-operatively and one month after surgery, skyline views at 30, 60, and 90° of flexion were taken, and patella shift and tilt were measured. With 2D-3D registration techniques using software, implant orientations were matched with the pre-operative CT and changes in the anterior part of the femoral prosthesis, condylar twist angle (CTA) for femoral rotation, and tibial rotation were evaluated. The relationships between morphological and rotational changes were evaluated.

RESULTS

There were significant differences in patella tilt at 60° and patella shift at all angles between pre- and post-operation (p < 0.05). No correlation was found between morphological changes in the anterior femur with patella tilt and shift. A positive correlation between postoperative CTA and patella shift at 90° was found (p < 0.05); however, no correlation was found between rotational alignment of the tibial component and patella tilt and shift.

CONCLUSIONS

ADVANCE MP TKA changed patello-femoral joint kinematics, compared to that found before surgery. The kinematic features were mainly due to the design concepts for tibio-femoral joint motion, indicating the difficulty to reproduce normal patello-femoral joint kinematics after TKA.