An increase in metal ion levels is seen after implantation of all MoM hip prosthesis due to release from the surface directly, more so during articulation and corrosion of the bearing surfaces. The bearing surfaces in MoM prosthesis consist of cobalt, chromium and molybdenum. Several case-reports of cobalt toxicity due to a MoM prosthesis have been published in the last decade. Cobalt intoxication may lead to a variety of symptoms: neuro-ocular toxicity (tinnitus, vertigo, deafness, blindness, convulsions, headaches and peripheral neuropathy), cardiotoxicity and thyroid toxicity. Nausea, anorexia and unexplained weight loss have been described. Systemic effects from metal ions even with well functioning implants or with ion concentrations lower than those associated with known adverse effects may exist and warrant investigation. The aim of this study is to investigate self-reported systemic complaints in association with cobalt ion concentrations in patients with any type of MoM hip prosthesis. A cohort study was conducted. Patients with both unilateral and bilateral, resurfacing and large head metal on metal total hip arthroplasties were included for the current study. Blood metal ion concentrations (cobalt and chromium) were measured by inductively coupled plasma mass spectrometry (ICP-MS). Based on the known cobalt toxicity symptoms of case-reports and toxicology reports a new non-validated questionnaire was developed. questions were subdivided in general questions/symptoms, vestibular symptoms, neurological symptoms, emotional health and cardio- and thyroid toxicity symptoms. Independent samples T test, Fishers Exact Test and Pearsons (R) correlation were used. Analysis was performed on two groups; a low cobalt ion concentration group and a high cobalt ion concentration group A total of 62 patients, 36 (58%) men and 26 (42%) women, were included with a mean age at surgery of 60.8 ± 9.3 years (41.6 – 78.1) and a mean follow up of 6.3 ± 1.4years (3.7 – 9.6). In these patients a total of 71 prosthesis were implanted: 53 unilateral and 9 bilateral. Of these, 44 were resurfacing and 27 large head metal on metal (LHMoM) total hip arthroplasties. Mean cobalt and chromium ion concentrations were 104 ± 141 nmol/L (9 – 833) and 95 ± 130nmol/L (6 – 592), respectively. Based on the different thresholds (120 – 170 or 220 nmol/L) the low cobalt ion concentration group consisted of 44 (71%), 51 (82%) or 55 (89%) subjects respectively. No differences were found in general characteristics, independently of the threshold. The composite score of vestibular symptoms (vision, hearing, tinnitus, dizziness) was significantly higher (p < .050) in all high cobalt ion concentrations groups, independent of the threshold value This study aimed to detect a trend in self-reported systemic complaints in patients with metal-on-metal hip arthroplasty due to raised cobalt ion concentrations. Vestibular symptoms were more common in high cobalt ion concentration groups independent of the three threshold levels tested. The upper limit of acceptable cobalt ion concentrations remains uncertain. With regards to proactively inquired, self-reported symptoms the threshold where effects may be present could be lower than values currently applied in clinical follow-up. It is unknown what exposure to elevated metal ion concentrations for a longer period of time causes with aging subjects. Further research with a larger cohort and a more standardized questionnaire is necessary to detect previously undiscovered or under-reported effects.

Anterior knee pain following primary total knee replacement (TKR) is a common problem with average reported rates in the literature of approximately 10%. Symptoms are frequently attributed to the patellofemoral joint, and the treatment of the patella during total knee replacement is controversial. There is no article in the literature that the authors know of that has specifically evaluated the effect of patella rim cautery on TKR outcome. This is a denervation technique that has historically been employed, with no evidence base. A prospective comparative cohort study was performed to compare the outcome scores of patients who underwent circumferential patella rim cautery, with those who did not. Patients who had undergone a primary TKR were identified from the unit's arthroplasty database. Two cohorts, who were age and gender matched, were established. None of the patients had their patella resurfaced, but all had a patellaplasty. The Low Contact Stress TKR (Depuy International) was used in all cases. The effect of circumferential patella rim cautery on the Oxford Knee Score (OKS) and the more anterior knee pain specific Patellar Score (PS) a minimum of 2 years post surgery was evaluated. Previous reports have suggested that a change of 5 points in the OKS represents a clinical difference. A sample size calculation based on an effect size of 5 points with 80% power and a p-value of 0.05 would require a minimum of 76 patients in each group. There were 94 patients who had undergone patellaplasty only, and 98 patients who had supplementary circumferential patella rim cautery during their primary TKR. The mean OKS were 34.61 and 33.29 respectively (p=0.41), while the PS scores were 21.03 and 20.87 (p=0.87). No statistically significant differences were noted between the groups for either outcome score. Patella rim cauterisation is unnecessary in primary TKR

Discitis in childhood is rare. It can be difficult to diagnose, particularly in the younger child, often leading to a delay in initiation of appropriate treatment. It is not known whether it represents an infective or an inflammatory process. Our aim was to review all cases treated at a regional children's hospital since the introduction of the departmental database. A retrospective review (64,058 cases), for the period 1990-2008 was performed. 12 cases were identified (3 male/9 female), with a biphasic age distribution; eight [mean 22 months old (12-32)] and four [mean 12 years old (11-13)]. Mean time to diagnosis from onset was 22 days, (5-49). Symptoms varied with age, no one less than 28 months complained of back pain, while all over 28 months did, to a varying degree. All the younger children presented primarily with a gait abnormality. 92% (11/12) were apyrexial on admission. WBC and CRP were normal in 83% (10/12). Venous blood cultures were negative in 89% (8/9). Only ESR was mildly raised, mean 30 (10-65). Radiographs showed loss of intervertebral disc height in 91% (10/11), earliest by 10 days following onset symptoms, mean 28 days. A technetium bone scan was performed in 42% (5/12) and an MRI of the lumbar spine, in 58% (7/12). All were positive for discitis. All occurred in the lumbar spine, 50% at L3/4. Antibiotics were used in 11/12 (92%), flucloxacillin alone in the majority 9/11. One had non-steroidal medication alone. No form of brace was used. Mean follow-up was 13.3 months (2-36). In all, symptoms had resolved by mean 6.5 weeks (2-12). No recurrence was noted. The common features of childhood discitis are presented; knowledge of these may aid the physician to come to a more rapid diagnosis of this uncommon paediatric condition

Meniscal tears commonly occur after a traumatic twisting injury to the knee (acute) or can form over time (degenerate). Symptoms include pain, swelling, and ‘locking’ of the knee. These symptoms are also commonly associated with osteoarthritis (OA). In some cases of OA, degenerative meniscal tears can also be present making it difficult to determine the cause of symptoms. Furthermore, acute meniscal lesions may be associated with early stage OA but often no radiological signs are evident. Many metabolites associated with joint disorders are released into the synovial fluid providing a real-time snap shot of joint pathology. The ability to examine concentrations of specific metabolites within synovial fluid could provide invaluable clinical information about the cause and stage of joint pathology. We have tested the hypothesis that ‘high resolution 1H-NMR can discriminate between osteoarthritic and meniscal tear-related metabolites within human synovial fluids and aid in clinical diagnosis.’. Method. Synovial fluid samples have been obtained during arthroscopy or knee replacement from patients with varying degrees of joint pathology (cartilage graded 0-4; meniscal tears classified as acute or degenerative). Samples were also taken from patients undergoing Anterior Cruciate Ligament (ACL) reconstruction with no additional pathology. Samples were analysed using 500 MHz 1H NMR spectroscopy. Chemical shifts were referenced to known concentration NMR internal standard (TSP), peaks identified by reference to published synovial fluid NMR spectra (1) and peak integrals measured using the Bruker software Topspin 2.0. Results. Spectroscopy revealed a number of differences in metabolites between OA, meniscal tear and ACL pathologies. These included significantly increased concentrations of glutamate, n-acetyl glycoprotein and β-hydroxybutyrate in OA (n=10) and acute meniscal tears (n=6) compared to ACL samples (p<0.05, T-test, n=6). Specific metabolites were also able to discriminate between OA with no meniscal tear and OA with meniscal tear synovial fluids. For example, concentrations of n-acetyl glycoproteins, glutamate and CH3 lipids were significantly increased in OA without tears (n=10) compared to OA plus meniscal tears (n=12); conversely ceramide concentrations were significantly increased in OA plus tears compared to OA only samples (p<0.05, T-test). Discussion. Our preliminary data indicate that the metabolic profiles of synovial fluid differ between OA, OA plus meniscal tear and ACL injuries. OA samples have increased concentrations of n-acetyl glycoproteins which can be indicative of degradative products from cartilage matrix such as hyaluronic acid. The increased concentrations of glutamate in OA may reflect activation of nociceptive, degradative and inflammatory processes (2). These metabolite concentrations were also increased in acute meniscal tear synovial fluids, which may reflect early signs of cartilage pathology. The differing levels of metabolites seen in OA alone compared to OA with meniscal tears may ultimately be a useful indicator of whether cartilage or meniscal pathology predominates within the joint