IntroductionChemerin is a chemotactic peptide which directs leukocytes expressing the chemokine-like receptor ChemR23 towards sites of inflammation. ChemR23 is a G protein-coupled receptor which binds several different ligands, and it is also expressed by other cell types such as adipocytes. In addition to chemotaxis, recent reports suggest that ChemR23 is capable of mediating either inflammatory or anti-inflammatory effects, depending on the type of ligand it binds. In the present study, we aimed to clarify whether human chondrocytes express ChemR23 and chemerin, and whether chemerin/ChemR23 signalling could affect secretion of inflammatory mediators.MethodsTissue sections were taken from human knee joints and labelled with antibodies towards chemerin and ChemR23. Chondrocytes from cartilage tissue were isolated, cultured and assessed for chemerin and ChemR23 expression by PCR and immunolabelling. Receptor activation and intracellular signalling were studied by assessment of phosphorylated mitogen activated protein kinases (MAPKs) and phosphorylated Akt after stimulating cells with recombinant chemerin21-157. Biological effects of chemerin21-157 were investigated by measuring secretion of pro-inflammatory cytokines and metalloproteases in cell supernatants.ResultsBoth serially cultured human articular chondrocytes and resident cells in native cartilage expressed chemerin and ChemR23. Stimulating cells with chemerin21-157 resulted in phosphorylation of p44/p42 MAPKs (ERK 1/2) and Akt (Ser 473). Also, significantly enhanced levels of the pro-inflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8), tumour necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and the matrix metalloproteases MMP-1, MMP-2, MMP-3, MMP-8 and MMP-13 were detected.ConclusionsThese results demonstrate that human chondrocytes express both the receptor ChemR23 and the ligand chemerin. Chemerin21-157 stimulation engaged signal-transduction pathways that further promoted inflammatory signalling in chondrocytes, as judged by an enhanced secretion of cytokines and metalloproteases. Taken together, the previously reported chemotaxis and the present findings suggest that the receptor and its ligand may play pivotal roles in joint inflammation.

Six patients suspected to have piriformis syndrome were operated in the hip region in an attempt to relieve pressure on the sciatic nerve. The piriformis muscle and tendon as well as their relationship to the sciatic nerve were found to be normal. However, the internal obturator muscle was found to be very tense, slightly hyperaemic and pressing the sciatic nerve. During Lasegue's testing on the operating table the internal obturator and not the piriformis muscle impinged on the nerve at an early stage in the hip flexion movement. A sectioning of the tendon to the internal obturator muscle near its insertion at the trochanter was performed. Median pain score was found to be reduced from the preoperative value (8.5) to that at 6 weeks (3.5) (P<0.05) and 3 (3.5) (P<0.05) and 6 months (5.5) (N.S.) postoperatively. No significant reduction of pain was found in a control group of six patients followed during the same period. Three patients who needed opioids preoperatively managed without such drugs 6 months after the operation. Two patients in the operated group were at work 50 and 100% after having been out of work for 3 and 10 years, respectively.

Ten patients, age 60 (48-75 years), with osteoarthritis (OA) of the hip and 10 patients, age 82.5 (60-90 years), with fracture of the collum femoris (FCF; minimum Garden stage III) underwent an open biopsy procedure from the internal obturator tendon in conjunction with a total hip replacement. The histological evaluation revealed that all tendon samples in the OA group revealed scar tissue; the corresponding was found in 50% of patients in the FCF group (P=0.02). There were also more GAGs (P=0.023) and calcium deposits (P=0.001) in the samples from the OA group. The ultrastructural evaluation revealed fewer small and medium-sized fibrils (P=0.001) and more non-collagenous extracellular matrix (ECM) (P=0.003) in the OA group. Taken together, the samples from the internal obturator tendon in the OA group revealed a more degenerative appearance with more scar tissue, change in fibril diameter distribution and more non-collagenous ECM. Our findings suggest that OA and periarticular tendinopathy are closely linked. Further research is needed to determine whether musculotendinous changes in the deep rotators are sequelae of joint pathology, or a contributing factor in the development of degenerative joint change.

Background:Recalcitrant lateral epicondylitis (elbow extensor–origin tendinosis) is a common cause of elbow pain with many treatment options. In the present study, the medium-term results after open release and radiofrequency microtenotomy are reported.Hypothesis:Microtenotomy would provide long-term pain relief that was as good as the open release method.Study Design:Prospective, randomized trial.Methods:Twenty-four patients randomized to either open release or microtenotomy were assessed after 5 to 7 years. Clinical examination and dynamic infrared thermography (DIRT) of both elbows were performed preoperatively and at the medium-term follow-up. Magnetic resonance imaging (MRI) of both elbows was performed at the medium-term follow-up.Results:Significant pain reduction was found using a visual analog scale (VAS) at the medium-term follow-up in both groups compared with the preoperative assessment (P < .005). The Mayo Elbow Performance Score (MEPS) increased significantly in both groups (P < .01). The improvement in grip strength was not significant in either group. There was no significant difference between the groups in terms of VAS, strength, and the MEPS. On the DIRT examinations, there were significantly fewer hot spots at the medium-term follow-up than preoperatively (P = .0067, both study groups together). The MRI examinations revealed grade II changes in the operated elbow in 1 patient in each group at the medium-term follow-up, while all the other MRI examinations revealed a normal tendon.Conclusion:In this prospective, randomized trial with a medium-term follow-up, the results were similar after surgical release and microtenotomy in patients with recalcitrant lateral epicondylitis. The hypothesis was thus verified.