To support and facilitate the rehabilitation of patients with physical limitations and aid the therapist, several robotic structures are being studied. Among the structures, the cable-driven robots stand out. The cable-driven robots are structures actuated by cables and have the advantages of being flexible and reconfigurable for each patient. The objective of this paper is to develop a theoretical model for knee flexion/extension force and moment using a cable-driven robot. The proposed model is necessary for elaborating a referential to which diagnosis can be made and the improvement of the patient evaluated. The presented theoretical model was validated through experiments with twelve sedentary and healthy volunteers. The first procedure tested ten subjects in three thigh angles for knee flexion motion; the second procedure tested two subjects in flexion and extension for the same thigh angle. The results show the validity of the model for 88.58% of the tests in an ANOVA analysis with a 99% confidence interval. The similarity of data for different gender, ages, and intrinsic factors was noted, implying that the model is representative and independent of the subject’s individuality. Differences between flexion and extension values were observed, which need to be studied in the future.

While the physical correlates of knee osteoarthritis are well documented, less well documented are aspects of psychological functioning that may affect overall health and functional status. This paper describes the findings of a cross-sectional analysis that examined the strength of the relationship between selected psychological factors and the walking ability of adults with knee joint osteoarthritis. The variables assessed were pain, depression, levels of self-efficacy for pain and other-symptoms management, walking endurance, walking speed, and perceived exertion when walking. The sample, including 57 persons with unilateral and 43 persons with bilateral radiographic and symptomatic knee osteoarthritis, mean age, 69.9 ± 1 years, underwent standard assessment procedures on a single test occasion using several validated questionnaires and a series of walking tests on level ground. Bivariate and multiple regression analyses revealed that (a) higher pain and other-symptoms self-efficacy scores were associated with lower levels of pain (r = −0.29, −0.20.), perceived exertion during a walking task (r = −0.29, −0.31), and depression scores (r = −0.46, −0.54) (p < 0.001); (b) subjects with higher levels of self-efficacy for managing symptoms other than pain also recorded faster and fast speed walking velocities than those with lower self-efficacy scores (r = 0.30, 0.31) (p < 0.001); (c) self-efficacy for pain was the strongest predictor of pain intensity, and self-efficacy for symptom management was the strongest predictor of perceived exertion during walking, depression, and pain self-efficacy. Although no cause–effect relationship can be deduced from a cross-sectional analysis, these data imply that efforts to heighten self-efficacy for pain and other-symptoms management may influence the affective status, function, and effort-related perceptions of people with knee osteoarthritis quite significantly.

Objectives: A randomized controlled trial (RCT) showed magnetic resonance imaging for patients waiting for knee arthroscopy did not reduce the number of arthroscopies. Our study aimed to identify decisions made by orthopedic surgeons about whether patients on a waiting list should proceed to arthroscopy, and to describe surgeons’ decisions.

Methods: Five surgeons were asked to Think Aloud (TA) as they made their decisions for twelve patients from the original RCT. Audiotapes of the decision making were transcribed for analysis.

Results: For five patients, surgeons agreed about proceeding with arthroscopy, although reasoning differed. In no cases did surgeons agree about not proceeding to arthroscopy. Agreement was more likely in patients with clinically diagnosed meniscal abnormality, and less likely in patients with osteoarthritis.

Conclusions: Surgeons’ decisions were influenced by patient wishes. For some patients, the decision to proceed with arthroscopy was based solely on clinical diagnosis; MRI may not be advantageous in these instances. Surgeons disagreed more often than they agreed about the decision to proceed with arthroscopy, particularly when OA was diagnosed. This has implications for decision making in the current NHS patient choice environment. Patients may choose a treatment provider from a list of available providers at time of original clinical assessment and diagnosis. The treating surgeon does not necessarily re-examine the patient until the day of surgery. Given the variation between surgeons about the merits of proceeding with arthroscopy, surgeons may end up in the invidious position of providing surgery to patients whom they do not believe will benefit from arthroscopy.

Objectives: Registers have proven to be a valuable instrument in the evaluation of arthroplasty procedures and the performance of implants. The aim of this study was to describe the structure, functioning, and content of arthroplasty registers in Europe and other parts of the world.

Methods: A search of technical reports was carried out through the Internet and in Medline/PubMed. The exhaustiveness of the information was confirmed using the links to Web pages of other registers and contacts with key people. Aims, methods in data collection and evaluation, internal structure and organization, participants, validity of the data, and other variables were assessed for each arthroplasty register using a qualitative content analysis of the texts.

Results: Fifteen arthroplasty registers were identified which published sufficient information to conduct a comparative analysis. Eight additional registers were identified but no information was available on the Internet or in English. Most registers were initiatives of an orthopaedic society receiving governmental funding. Data were collected using standardized clinical forms and additional information from clinical-administrative datasets or other registers (mortality, implant costs, hip fractures). The main outcome measure of these registers is survival of the prostheses. Registers use the Internet and their annual reports as the main strategy for the dissemination and feed-back of their results.

Conclusions: Scientific or professional societies and the public health administration should collaborate in the development of arthroplasty registers. To adequately assess the results of observational data information on the structure, the process of arthroplasty interventions and patients characteristics should be collected.

Objectives: Chondral defects of the knee cartilage are prevalent. Autologous chondrocyte implantation (ACI) and mosaicplasty are increasingly used to treat symptomatic knee defects. This study assessed the costs and health status outcomes after ACI and mosaicplasty.

Methods: Patients were eligible to participate in this cross-sectional study if they received ACI or mosaicplasty at the Royal National Orthopaedic Hospital between 1997 and 2001 or were on a waiting list for ACI. Secondary-care resource use was collected to 2 years postoperatively using a resource collection proforma. Participants responded to postal questions about sociodemographic characteristics and knee-related (Modified Cincinnati Knee Rating System) and general health status (EQ-5D).

Results: Fifty-three ACI, twenty mosaicplasty, and twenty-two patients waiting for ACI participated. The average cost per patient was higher for ACI (£10,600: 95 percent confidence interval [CI], £10,036–£11,214) than mosaicplasty (£7,948: 95 percent CI, £6,957–£9,243). Postoperatively, ACI and mosaicplasty patients (combined) experienced better health status than those waiting for ACI. ACI patients tended to have better health status outcomes than mosaicplasty patients (not statistically significant). Estimated average EQ-5D social tariff improvements for quality-adjusted life year (QALY) calculations were 0.23 (ACI) and 0.06 (mosaicplasty). Average costs per QALY were £23,043 (ACI) and £66,233 (mosaicplasty). The incremental cost effectiveness ratio (ICER) for providing ACI over mosaicplasty was £16,349.

Conclusions: Average costs were higher for ACI than mosaicplasty. However, both the estimated cost per QALY and ICER for providing ACI over mosaicplasty fell beneath an implicit English funding threshold of £30,000 per QALY. Prospective studies should include measures of utility to confirm the estimated cost utility ratios of ACI and mosaicplasty.

Background and objective: We assessed the analgesic efficacy of postoperative epidural infusions of ropivacaine 0.1 and 0.2% combined with sufentanil 1 μg mL−1 in a prospective, randomized, double-blinded study.

Methods: Twenty-two ASA I—III patients undergoing elective total-knee replacement were included. Lumbar epidural blockade using ropivacaine 0.75% was combined with either propofol sedation or general anaesthesia for surgery. After surgery, the epidural infusion was commenced. Eleven patients in each group received either an epidural infusion of ropivacaine 0.1% with 1 μg mL−1 sufentanil (Group 1) or ropivacaine 0.2% with 1 μg mL−1 sufentanil (Group 2) at a rate of 5–9 mL h−1. All patients had access to intravenous pirinatrimide (piritramide) via a patient-controlled analgesia (PCA) device.

Results: Motor block was negligible for the study duration in both groups. There was no significant difference with the 100 mm visual analogue scale (VAS) scores, with the consumption of rescue analgesia or with patient satisfaction. Patients in Group 1 experienced significantly less nausea (P < 0.05) than those in Group 2. Both treatment regimens provided effective postoperative analgesia with only a minimal use of supplemental opioid PCA.

Conclusions: We recommend the use of ropivacaine 0.1% with 1 μg mL−1 sufentanil for postoperative analgesia after total knee replacement as it provides efficient pain relief with no motor block of the lower limbs. In addition, compared with 0.2% ropivacaine with sufentanil, the mixture reduces local anaesthetic consumption without compromise in patient satisfaction or VAS scores. Patients even experience less nausea.

We studied a number of factors that may be associated with urinary retention, in particular the method of postoperative analgesia delivery, in 47 men and 69 women undergoing lower limb joint replacements. The following factors were studied: age, gender, height, weight, previous history of urinary retention, presence of symptoms suggestive of urinary tract obstruction, type of anaesthetic (general anaesthetic or spinal anaesthetic), type of postoperative analgesia (intramuscular or patient-controlled analgesia with morphine) and the total dose of morphine given. Urinary retention developed in 18.1% of patients. Stepwise logistic regression analysis was used to identify independent explanators of an increased probability of developing urinary retention. Three factors emerged – male gender, increasing age and the use of patient-controlled analgesia.

The efficacy of an integrated autotransfusion regimen, including pre-donation and perioperative salvage of autologous blood, was prospectively evaluated in 2884 patients undergoing total hip (n=2016) or knee arthroplasty (n = 480), and hip revision (n = 388) with either balanced general, regional, or integrated epidural/general anaesthesia. Allogenic concentrated red blood cells were transfused in the presence of symptomatic anaemia or when haemoglobin concentration was < 6gdL−1 (10gdL−1 in patients affected by cerebrovascular or coronary artery disease) after all salvaged and pre-donated autologous blood had been transfused. A total of 278 patients (9.6%) received allogenic blood. Risk factors for allogenic blood transfusion were: preoperative haemoglobin concentration < 10gdL−1 (after autologous blood pre-donations) (Odds ratio: 8.7; 95% CI: 6.5–16.8; P=0.004), hip revision versus hip or knee arthroplasty (Odds ratio: 5.8; 95% CI: 3.9–8.5; P=0.0001) and inability in obtaining the number of predonations required by the Maximum Surgery Blood Order on Schedule (Odds ratio: 3.4; 95% CI: 2.7–4.1; P=0.0001). The incidence of perioperative complications, including wound infection and haematoma, as well as myocardial ischaemia, respiratory failure and thromboembolic complications, was higher in those patients requiring allogenic blood transfusion (29.8%) than that observed in patients receiving only autologous blood (6.6%) (P=0.0005); while the mean time duration from surgical procedure to patient discharge from the orthopaedic ward was shorter in those patients not receiving allogenic blood transfusion (12 days; 25–75th percentiles: 8–14 days) than in those patients who required perioperative transfusion with allogenic blood (15 days; 25–75th percentiles: 10–17 days) (P=0.0005). In conclusion, this prospective study highlighted the clinical relevance of applying an extensive and integrated autotransfusion regimen in order to reduce allogenic blood transfusion and associated complications in patients undergoing major joint replacement.

Objectives: To examine the influence of a picture archiving and communication system (PACS) on the length of stay (LOS) for patients receiving total hip replacement (THR) or total knee replacement (TKR) procedures.

Methods: A before-and-after design was used. Data were collected on all THR and TKR procedures at Hammersmith Hospital from 1993–96. A regression approach was used to examine the influence of PACS on LOS. Factors such as patient age, sex, and physician were controlled for.

Results: Type of admission and discharge, month of procedure, complications, and number of procedures all significantly influenced LOS for patients undergoing THR. For patients receiving TKR, age, sex, admission, prosthetic complications, number of procedures, and PACS significantly influenced LOS.

Conclusions: While this study shows an apparent reduction of 25% in the average LOS for TKR patients at the time PACS was introduced, this is unlikely to be a true PACS effect and no similar reduction in LOS was shown for THR patients.

The increasing use of ambulatory surgery requires methods of anaesthesia that allow patients to be discharged soon after the operation is completed. Spinal anaesthesia is usually simple and quick, and the incidence of post-spinal headache has been reduced by using non-cutting small-gauge needles. Limiting the spread of spinal anaesthesia, as long as it still provides analgesia for surgery, should reduce the haemodynamic effects and speed recovery. Restricted spinal anaesthesia, intended to be unilateral using 0.18% hypobaric bupivacaine via a 25G or 27G Whitacre unidirectional needle, was compared with epidural anaesthesia (using a mixture of lignocaine and prilocaine) in 64 matched-pair patients undergoing ambulatory arthroscopy. Motor blockade, assessed for the specific myotomes L2 to S1, was significantly more unilateral in the spinal group. Two patients in the spinal group and nine patients in the epidural group were treated for hypotension (P < 0.05). One patient in the spinal group developed a post-spinal headache. One patient in the epidural group rated the anaesthesia poor.

This present study investigated the effects of intraarticular morphine administration in 1mg and 5mg doses on post-operative pain relief and analgesic requirements for patients undergoing arthroscopic procedures. At the end of the operation patients were randomly allocated in a double-blinded fashion into three groups. The control group (Group 1) received normal saline 20 mL intraarticularly. The patients in the second and third groups received intraarticular morphine sulphate 1 and 5mg in saline 20 mL, respectively. Post-operative pain was assessed on the 1st, 6th and 24th hour by visual analogue scale (VSA). Supplementary analgesic requirement and possible complications were also followed. The intensity of pain and analgesic requirement were reduced more in the morphine 5mg group than in the control group. It is concluded, that the administration of intraarticular morphine 5mg provides long-lasting and effective analgesia after knee arthroscopy.