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Purpose: Cementless unicompartmental knee replacement (UKR) was introduced to address some of the problems that can occur following cemented UKR. The aim of this study was to report the 5-year experience of the first 512 medial cementless Oxford UKR implanted by two surgeons for the recommended indications.Methods: The first consecutive 512 cementless Phase 3 Oxford UKRs implanted by two surgeons for the recommended indications between June 2004 and October 2013 were prospectively identified and followed up independently. All the procedures were carried out through a minimally invasive approach without eversion or dislocation of the patella. Patients were assessed clinically pre-operatively and at 1, 2, 5, 7 and 10 years after surgery with functional outcome scores and radiographs.Results: There were eight reoperations of which six were revisions giving a 5-year survival of 98 % (95 % CI 94-100 %). At a mean follow-up of 3.4 years (1.0-10.2), the mean OKS was 43 (SD 7), AKSS (objective) was 81 (SD 13), and AKSS (functional) was 86 (SD 17). The first 120 cases had a minimum follow-up of 5 years (mean 5.9; range 5-10.2). In these patients, the mean OKS was 41 (SD 8), AKSS (objective) was 81 (SD 14), and AKSS (functional) was 82 (SD 18). There were no femoral radiolucencies and no complete tibial radiolucencies. 11 % of tibial components had partial radiolucent lines; the remaining 89 % had no radiolucencies.Conclusion: The clinical results are as good as or better than those previously reported for cemented fixation. The radiographic results are better with secure bony attachment to the implants in every case.Level Of Evidence: IV. [ABSTRACT FROM AUTHOR]

Purpose: Lateral progression of arthritis following medial unicompartmental knee arthroplasty (UKA), although infrequent, is still the most common reason for revision surgery. Treatment options normally include conversion to total knee arthroplasty. An alternative strategy for some patients may be addition of a lateral UKA. We report the first results of staged bi-compartmental UKA (Bi-UKA) strategy.Methods: We retrospectively selected from our UKA database patients who underwent a lateral UKA to treat a symptomatic lateral osteoarthritis progression after a medial UKA. The analysis included a clinical and radiological assessment of each patient.Results: Twenty-five patients for a total of 27 knees of staged Bi-UKA were carried out in a single centre. The mean time interval between primary medial UKA and the subsequent lateral UKA was 8.1 years (SD ± 4.6 years). The mean age at the time of the Bi-UKA was 77.1 years (SD ± 6.5 years). The median hospital stay was 3 (range 2-9 days) days, and the mean follow-up after Bi-UKA was 4 years (SD ± 1.9 years). The functional scores showed a significant improvement as compared to the pre-operative status (paired t test, p = 0.003). There were no radiological evidences of failure. None of the patients needed blood transfusion, and there was no significant complications related to the surgical procedure without further surgeries or revisions at final follow-up.Conclusions: These results suggest that addition of a lateral UKA for arthritis progression following medial UKA is a good option in appropriately selected patients.Level Of Evidence: Observational study without controls, Level IV. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate clinical outcome, failures, implant survival, and complications encountered with cementless fixation in unicompartmental knee arthroplasty (UKA).Methods: A systematic review of the literature on cementless fixation in UKA was performed according to the PRISMA guidelines. The following database was comprehensively searched: PubMed, Cochrane, Medline, CINAHL, Embase, and Google Scholar. The keywords "unicompartmental", "unicondylar", "partial knee arthroplasty", and "UKA" were combined with each of the keyword "uncemented", "cementless" and "survival", "complications", and "outcome". The following data were extracted: demographics, clinical outcome, details of failures and revisions, cumulative survival, and complications encountered. The risk of bias of each study was estimated with the MINORS score and a further scoring system based on the presence of the primary outcomes.Results: From a cohort of 63 studies identified using the above methodology, 10 papers (1199 knees) were included in the final review. The mean follow-up ranged from 2 to 11 years (median 5 years). The 5-year survival ranged from 90 to 99 % and the 10-year survival from 92 to 97 %. There were 48 revisions with an overall revision rate of 0.8 per 100 observed component-years. The most common cause of failure was progression of osteoarthritis in the retained compartment (0.9 %). The cumulative incidence of complications and revisions was comparable to that reported in similar studies on cemented UKAs. The advantages of cementless fixation include faster surgical time, avoidance of cementation errors, and lower incidence of radiolucent lines.Conclusions: Cementless fixation is a safe and effective alternative to cementation in medial UKA. Clinical outcome, failures, reoperation rate, and survival are similar to those reported for cemented implants with lower incidence of radiolucent lines.Level Of Evidence: IV. [ABSTRACT FROM AUTHOR]

Purpose: Chondrocalcinosis can be associated with an inflammatory arthritis and aggressive joint destruction. There is uncertainty as to whether chondrocalcinosis represents a contraindication to unicompartmental knee arthroplasty (UKA). This study reports the outcome of a consecutive series of patients with chondrocalcinosis and medial compartment osteoarthritis treated with UKA matched to controls.Methods: Between 1998 and 2008, 88 patients with radiological chondrocalcinosis (R-CCK) and 67 patients with histological chondrocalcinosis (H-CCK) were treated for end-stage medial compartment arthritis with Oxford UKA. One-to-two matching was performed to controls, treated with UKA, but without evidence of chondrocalcinosis. Functional outcome and implant survival were assessed in each group.Results: The mean follow-up was 10 years. The mean Oxford Knee Score (OKS) at final follow-up was 43, 41 and 41 in H-CCK, R-CCK and control groups (change from baseline OKS was 21, 18 and 15, respectively). The change was significantly higher in H-CCK than in control but was not significantly different in R-CCK. Ten-year survival was 96 % in R-CCK, 86 % in H-CCK and 98 % in controls. Although the survival in H-CCK was significantly worse than in control, only one failure was due to disease progression.Conclusion: The presence of R-CCK does not influence functional outcome or survival following UKA. Pre-operative radiological evidence of CCK should not be considered to be a contraindication to UKA. H-CCK is associated with significantly improved clinical outcomes but also a higher revision rate compared with controls.Level Of Evidence: Case control study, Level III. [ABSTRACT FROM AUTHOR]

Introduction: The Musculoskeletal Infection Society (MSIS) has defined specific clinical and laboratory criteria for the diagnosis of periprosthetic joint infection (PJI). In this study we assessed the diagnostic utility of MSIS microbiological and histological criteria for PJI in 138 cases of septic and aseptic knee implant failure.Materials and Methods: Intra-operative samples from 60 cases of knee septic implant failure (SIF) and 78 cases of aseptic implant failure (AIF), defined on the basis of clinical, laboratory and operative findings/surgical management, were analysed microbiologically and histologically. Findings were correlated with the final clinical diagnosis and the specificity, sensitivity, accuracy, positive and negative predictive value of MSIS microbiological and histological criteria for knee PJI were assessed.Results: 80% of SIF cases showed culture of the same organism from two or more samples (ie MSIS microbiological criteria for definite PJI); 8.3% grew an organism from one sample, and 11.7% showed no growth from any sample. 23.1% of AIF cases grew an organism from one sample and 76.9% showed no growth from any sample. MSIS histological criteria for PJI identified 96.7% of SIF cases. The sensitivity, specificity, accuracy and positive and negative predictive value of MSIS histological criteria for PJI were 96.7%, 100%, 98.6%, 100% and 97.5%, respectively. MSIS microbiological and histological criteria identified all AIF cases.Conclusions: Knee PJI is more often identified by current MSIS histological than microbiological criteria. A significant proportion of SIF cases show either no growth or growth of an organism from only one sample. AIF is identified by both MSIS microbiological and histological criteria. Correlation of clinical, radiological and laboratory findings is required for the diagnosis of knee PJI. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament-deficient (ACLD) knee kinematics during high-demand activities are poorly understood. We have devised a new method, using gait analysis, to more accurately assess 3-D in vivo kinematics of the knee. This has enabled us to report on how knee kinematics are altered after ACL rupture, during running and cutting. Fifteen unilaterally ACLD subjects were assessed using a 12-camera 100 Hz VICON motion analysis system. Simultaneous electromyographical (EMG) recordings were used to assess the role of the sensorimotor system in knee joint stability. All subjects were able to perform demanding cutting activities without experiencing symptoms of instability. We found that running produces fundamentally different kinematic patterns to those seen during walking. Tibiofemoral translation in the anteroposterior plane is controlled to within normal limits. Conversely, coronal translation and rotation are poorly controlled. We found that the injured leg was maintained in greater extension during the stance phase of all running activities studied and that the quadriceps muscle was active for longer during this period. We believe that low-demand activities, such as walking, do not reproduce kinematics relevant to ACLD instability and that future investigations into functional instability in the ACLD knee should focus on coronal and rotational displacements. [ABSTRACT FROM AUTHOR]

Purpose: Shortening of the patella tendon has been noted after total knee arthroplasty and has been associated with diminished functional outcomes. Traumatic and/or ischaemic injury peri-operatively are suggested causes. The Oxford domed lateral unicompartmental knee arthroplasty (UKA) requires a vertical incision through the patella tendon to facilitate orientation of the proximal tibial saw cut; this may induce scarring or impair vascularity of the tendon and can cause shortening. This study investigated the hypothesis that the trans-patella tendon incision increases the incidence of patella tendon shortening after domed lateral UKA when compared to flat lateral UKA performed without the trans-patella tendon incision. Methods: The radiographs of 50 patients who underwent domed lateral UKA, using the trans-patella tendon approach, and a cohort of 30 patients who underwent flat lateral UKA, in which an incision through the patella tendon was not employed, were reviewed retrospectively. The patella tendon length (PTL) and the Insall-Salvati ratio were measured. In addition, pre-operative and post-operative clinical scores were recorded using both the OKS and AKSS. A change in PTL of greater than or equal to 10 % was considered to be significant. Results: In the domed lateral UKA group, 13 patients demonstrated a >10 % change in the PTL at 1-year post-surgery (2 shortened and 11 lengthened). In the flat lateral UKA group, nine patients demonstrated a significant change in the PTL at 1-year post-surgery (2 shortened and 7 lengthened). Conclusion: This study demonstrated that using a trans-patella approach during lateral domed UKA surgery did not significantly increase patella tendon shortening and did not result in reduced clinical outcomes. Level of evidence: Retrospective, comparative study, Level III. [ABSTRACT FROM AUTHOR]

Purpose: Indications for unicompartmental knee arthroplasty (UKA) vary between units. Some authors have suggested, and many surgeons believe, that medial UKA should only be performed in patients who localise their pain to the medial joint line. This is despite research showing a poor correlation between patient-reported location of pain and radiological or operative findings in osteoarthritis. The aim of this study is to determine the effect of patient-reported preoperative pain location and functional outcome of UKA at 1 and 5 years. Methods: Preoperative pain location data were collected for 406 knees (380 patients) undergoing Oxford medial UKA. Oxford Knee Score, American Knee Society Scores and Tegner activity scale were recorded preoperatively and at follow-up; 272/406 (67 %) had pure medial pain, 25/406 (6 %) had pure anterior knee pain, and 109/406 (27 %) had mixed or generalised pain. None had pure lateral pain. The primary outcome interval is 1 year; 132/406 patients had attained 5 years by the time of analysis, and their 5-year data are presented. Results: At 1 and 5 years, each group had improved significantly by each measure [mean ΔOKS 15.6 (SD 8.9) at year 1, 16.3 (9.3) at year 5]. There was no difference between the groups, nor between patients with and without anterior knee pain or isolated medial pain. Conclusions: No correlation is demonstrated between preoperative pain location and outcome. We conclude that localised medial pain should not be a prerequisite to UKA and that it may be performed in patients with generalised or anterior knee pain. Level of evidence: Therapeutic, Level II. [ABSTRACT FROM AUTHOR]

The principles of shared decision making are well documented but there is a lack of guidance about how to accomplish the approach in routine clinical practice. Our aim here is to translate existing conceptual descriptions into a three-step model that is practical, easy to remember, and can act as a guide to skill development. Achieving shared decision making depends on building a good relationship in the clinical encounter so that information is shared and patients are supported to deliberate and express their preferences and views during the decision making process. To accomplish these tasks, we propose a model of how to do shared decision making that is based on choice, option and decision talk. The model has three steps: a) introducing choice, b) describing options, often by integrating the use of patient decision support, and c) helping patients explore preferences and make decisions. This model rests on supporting a process of deliberation, and on understanding that decisions should be influenced by exploring and respecting "what matters most" to patients as individuals, and that this exploration in turn depends on them developing informed preferences. [ABSTRACT FROM AUTHOR]

This article describes a technique to manage dislocations of mobile bearing lateral unicompartmental knee replacements. When dislocations occur, the bearing usually subluxes medially over the medial wall of the tibial component into the intercondylar notch. By positioning small fragment screws with their heads above the vertical wall, thereby increasing the height of the wall, subsequent dislocations can be prevented. Seven cases treated in this manner are reported, of which one of the seven has redislocated. In the remaining six, their clinical outcomes are comparable to the outcomes of those without dislocations. Level of evidence Retrospective case series, Level IV. [ABSTRACT FROM AUTHOR]

Between January 1995 and Jul 1997, 474 patients with anterior knee pain resistant to conservative treatment were referred for MR of the knee. The MR examination consisted of routine sequences with an additional patellofemoral dynamic examination using a technique that has been developed at this institution. The dynamic study examines both knees simultaneously, with the patient supine and the quadriceps loaded. No gating or restraint apparatus is needed. Patellar subluxation or tilt was present in 188(40%) of cases, bilateral in 104 and unilateral in 84 cases (right 39, left 45). It was classified as mild in 51%, moderate in 39% and severe in 10%. Subluxation was more prevalent in females than males (42% vs. 37%) and this was most obvious in the severe group where 68% were female. In 90 knees selected at random, four measurements of patellofemoral morphology were obtained using reconstructed images from a volume gradient echo sequence. These measurements were correlated with the degree of subluxation or tilt. A tibial tubercle distance greater than 20 mm, a femoral sulcus angle greater than 150 degrees, sulcus depth less than 4 mm were specific for subluxation but no measurement proved to be sufficiently sensitive to preclude a tracking study. MRI can be used to define more precisely the anatomy of the extensor mechanism and its relationship to the femur and tibia, in both a static and dynamic setting. In this way, patients with anterior knee pain can be classified more accurately and the outcomes of treatment more reliably assessed. [ABSTRACT FROM AUTHOR]

Outside of the laboratory, bacterial cells are constantly exposed to stressful conditions, and an ability to resist those stresses is essential to their survival. However, the degree of stress required to bring about cell death varies with growth phase, amongst other parameters. Exponential phase cells are significantly more sensitive to stress than stationary phase ones, and a novel hypothesis has recently been advanced to explain this difference in sensitivity, the suicide response. Essentially, the suicide response predicts that rapidly growing and respiring bacterial cells will suffer growth arrest when subjected to relatively mild stresses, but their metabolism will continue: a burst of free-radical production results from this uncoupling of growth from metabolism, and it is this free-radical burst that is lethal to the cells, rather than the stress per se. The suicide response hypothesis unifies a variety of previously unrelated empirical observations, for instance induction of superoxide dismutase by heat shock, alkyl-hydroperoxide reductase by osmotic shock and catalase by ethanol shock. The suicide response also has major implications for current [food] processing methods. [ABSTRACT FROM AUTHOR]

Injection of picrotoxin solutions into the pericardium of lobsters, Homarus americanus, to produce final, estimated blood concentrations of between 8×10M and 4.5×10M led to disruption of the normal motor output to the scaphognathite. The phase separation of the starts of the bursts in the D1 and D2 muscles (Young, 1975) was reduced on the average by 49%; that of L1 and L2 muscles by 16%. The durations of the D1 and L1 bursts increased by 94% and 48% respectively. The phase separation between the starts of the levator and depressor portions of the cycle was not altered. Whilst rhythmic activity persisted ventilatory rates were depressed, and reversals and ventilatory pauses continued to occur. The rate of reversals and their pattern were not greatly altered. Inexplicably, tonic, synchronous spikes occurred in all four groups of muscles, levator and depressor, during periods of severe disruption. It was concluded that in spite of this, the observations supported the proposals of Young (1975) that (a) recruitment of the D2 and L2 bursts normally is delayed partly by inhibition from D1 and L1 units respectively, and (b) termination of D1 and L1 bursts results normally from inhibition due to activity in D2 and L2 units respectively. The findings also indicated that the synaptic mechanism determining timing within the depressor and levator sessions differs fundamentally from that operating between sessions. One mechanism may be based on picrotoxin-sensitive, and the other on picrotoxin-insensitive inhibition. [ABSTRACT FROM AUTHOR]

This article focuses on superior macular sparing in central retinal artery occlusion due to sickle cell anaemia. A 32-year-old African male with homozygous sickle cell disease (SS disease) presented to the eye casualty with a 24-h history of blurred vision in the right eye. He had consumed several pints of alcohol on the two evenings prior to presentation, but had failed to ensure a full rehydration with water. Ocular complications in SS disease are unusual. They are much more common in sickle cell thalassaemia (Sthal) and sickle cell C disease (SC). The postulated reason is that in SS disease, the severe anaemia and thus low haematocrit lead to a lower blood viscosity than in Sthal or SC where anaemia is less marked and the haemoglobins exist in a higher concentration.