Outcome Of Total Knee Replacement Research Articles

To study surgical outcome of various surgical procedures of lateral release in valgus knee in total knee arthroplasty

<p class="abstract"><strong>Background:</strong> Fixed valgus deformity presents a major challenge in total knee arthroplasty (TKA), especially in moderate or severe cases. In knee arthritis, fixed-varus deformity (50 to 55%) is three times more frequent than fixed-valgus deformity (10 to 15%). Valgus deformity occurs more commonly in rheumatoid arthritis and also in osteoarthritis with hypoplasia of the lateral femoral condyle. Valgus deformity is often associated with flexion or external rotation contracture of the knee. In this study we aim to study the surgical outcome of total knee replacement in valgus deformity via standard medial parapatellar approach using various techniques like Pie –Crusting release of lateral structures or combined technique of pie crusting and standard release of lateral structures. Aim: To evaluate surgical outcome of various surgical techniques via standard medial parapatellar approach in fixed valgus deformity in Total Knee Arthroplasty.</p><p class="abstract"><strong>Methods:</strong> The present study involved both male and female patients with osteoarthritis of knee with valgus deformity. In present series, 26 consecutive patients of osteoarthritis with valgus deformity operated with total knee replacement were included. Previously operated cases of high tibial osteotomy and patients having contraindication for TKA were excluded from the study.<strong></strong></p><p class="abstract"><strong>Results:</strong> Valgus angle in this study was between 13 to 27 degree with average 17.84 degree. These results were comparable to many such similar studies. In our study, post operatively, knee society score was average 87.69 and function knee score was 82.5. Mean range of motion was 105 degree. In our study, mean tibiofemoral alignment improved from 17.84 valgus to 4.7 valgus.</p><p class="Default"><strong>Conclusions:</strong> Knee society score is excellent with both techniques and there is no difference in both techniques Iliotibial band and posterolateral capsule are most common structures that require release. Initial ligament balancing should be done with pie crusting and then sequential lateral release if require. </p>

Multifactorial analysis of patient dissatisfaction after TKR – the influence of psychological factors

Objectives:The published rates of dissatisfaction following total knee replacement (TKR) range between 11-18%, with residual symptoms and psychological distress being important features. The aims of this study were to identify the prevalence and causes of dissatisfaction in a cohort of private practice patients, and to describe a post-operative management program which may improve satisfaction with their replaced knee in these patients.Methods:A cohort of 375 patients with unilateral TKR was evaluated to identify patients who were dissatisfied with TKR. Dissatisfied and satisfied patients were matched in terms of age, gender, follow-up duration and BMI. Psychological evaluation was performed using the pain catastrophizing scale (PCS), Depression, Anxiety and Stress Scale (DASS) and the Multidimensional Health Locus of Control (MHLC) scale. The pre and post-operative Oxford knee scores (OKS) and range of motion (ROM), preoperative grade of osteoarthritis, and prevalence of comorbidities were also compared between groups. Patients indicating dissatisfaction with their TKR were then followed up by phone on a second occasion 12months later. Those that indicated enduring dissatisfaction were invited to participate in a chronic pain program utilising cognitive behavioural therapy, desensitisation and coping strategies. Patients referred to the program were screened by the therapists for inclusion and enrolled into a flexible course of therapy. Pre- and post- intervention questionnaires will be used to determine the effect of the program on satisfaction rates (5-point Likert scale) and psychological responses to pain.Results:The final cohort consisted of 301 patients (response rate 80%), with 24 patients (6.5%) dissatisfied with the result of TKR. Persistent pain was the most common reason for dissatisfaction (n=10). Dissatisfied patients reported a significantly (P = 0.03) higher mean PCS score (mean±SD, 11.3±10.3), compared to satisfied patients (5.4±6.3) and a significantly (P = 0.02) higher depression component of the DASS (3.5±3.3 vs 1.4±1.6). In addition, dissatisfied patients returned a significantly (P = 0.02) lower internal locus of control (16.6±8.2 vs 21.3±8.2). The dissatisfied group also exhibited a reduced improvement in the OKS and ROM, as well as a lower preoperative grade of osteoarthritis compared to satisfied patients. Preliminary analysis revealed that five patients (21%) became satisfied with their knee despite no intervention occurring between measurements. Of the remaining patients, five patients (21%) did not think their ongoing issues were severe enough to warrant further intervention, and nine patients (38%) were referred directly to the program. It is expected that these results will shed new light on the potential management options for these patients that identify as dissatisfied after a primary unilateral TKR.Conclusion:Dissatisfied patients exhibit higher scores for catastrophisation and depression, with lower self confidence in managing their knee symptoms. In addition, they have lesser improvements in the OKS and ROM. Thus, both physical as well as psychological factors contribute to dissatisfaction. Identification of these factors can help in planning focused interventions to address dissatisfaction. This is the longest follow-up of such a cohort; our results so far indicate that 21% of such patients can improve spontaneously with time which challenges some conventional beliefs. The results of the 38% of patients who remain dissatisfied and will undergo the program will determine whether such an intervention will be worthwhile in this difficult clinical situation.

Outcomes of primary total knee arthroplasty in patients with Parkinson’s disease: A Case Control Comparison Study

Introduction and Aims:There is considerable debate and a paucity of evidence regarding whether Total Knee Replacement (TKR) is of benefit in patients with Parkinson’s disease (PD) and knee osteoarthritis, and whether PD would compromise the outcome of TKR. Therefore, we aimed to compare the effect of TKR on range of motion and Oxford Knee Scores (OKS) between PD patients and age-matched controls at 1 year follow-up.Methods:A cohort of 45 knees from 35 patients was identified as having a confirmed diagnosis of Parkinson’s disease and received a primary TKR between January 2004 and December 2015, which was extracted from a clinical database (Socrates, v3.5, Orthosoft, AUS) maintained by two orthopaedic surgeons in two hospitals. An age-matched control group (mean age: 73 years) of 45 knees from 41 patients without Parkinson’s disease was randomly computer-generated from the same database. The indication for TKR in both groups was osteoarthritis, an independent assessment of each knee to meet appropriate selection criteria for TKR, as well as preoperative physician review for medical comorbidities. Outcome measures analysed in the study were the difference in pre-operative range of motion (RoM) and 12-point Oxford Knee Scores and at 1-year follow-up respectively. Postoperative complications and revisions were also recorded during the follow-up period.Results:In the PD group, RoM improved from a mean of 100 degrees preoperatively to 114 degrees at 12 months, compared to the control group which improved from a mean of 102 degrees to 114 degrees respectively. OKS in the Parkinson’s group improved from a mean of 23 preoperatively to 38 at 12 months compared to 23 preoperatively and 40 at 12 months in the control group. After adjusting for sex, we found that the difference in the ROM and OKS between the Parkinson’s and control groups was not significantly different (p = 0.9725; 0.6450 respectively). Furthermore, in all Parkinson’s patients the minimal clinically important difference for OKS (≥6) was achieved at 1-year follow-up (4). There were no mortalities during the study follow-up period, with 4 complications in the PD group (DVT, superficial infection) and two in the control group (DVT, bowel pseudo-obstruction).Conclusions:This study demonstrates that TKR provides comparable outcomes with regard to range of movement and ambulatory function in patients with Parkinson’s disease who are also suffering from severe osteoarthritis. We also feel that TKR has an acceptable complication profile in this subgroup of patients. The presence of PD does not appear to compromise the outcome of TKR in these patients, and the same indications for TKR should therefore apply as for the general OA population.

Preoperative pain sensitization and total knee replacement outcome

Preoperative pain sensitization and total knee replacement outcome

Translation and validation of the 12-item Oxford knee score for use in Finland

BackgroundThe focus in the reporting of results after total knee replacement (TKR) has changed from surgeon/radiologist-based scores to patient-reported outcome measures (PROMs). The questionnaires used in subjective outcome are often originally published in English and need to be validated in different languages. The aim of our study was to investigate the feasibility, validity, reliability, and responsiveness of the Finnish language version of the Oxford Knee Score (OKS-S) questionnaire.MethodsThe original OKS questionnaire was translated using a forward/backward protocol. The OKS-S questionnaire was sent to 225 patients who were scheduled to undergo TKR surgery. The assessment was repeated 1 year after the index operation. Half of the patients also received the RAND-36 questionnaire with the OKS-S questionnaire and the other half the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. 30 patients twice received the OKS-S questionnaire preoperatively for the test-retest assessment.ResultsFeasibility was acceptable with a response rate of 96% in both pre- and postoperative assessments. Correlation between OKS-S questionnaire and all domains of the KOOS questionnaire and the physical domains in the RAND-36 questionnaire was high, and confirmed both good criterion and convergent validity. Content validity was good since no ceiling or floor effect was observed. In the test-retest assessment, all but 2 patients were within the 95% limits of agreement. Responsiveness was large according to effect sizes.ConclusionsOur data suggests that the OKS-S questionnaire is suitable for the assessment of both the preoperative status and the outcome of TKR in Finnish speaking patients.

Prospective study of clinical and functional outcome of total knee replacement in osteoarthritic knee

<p class="abstract"><strong>Background:</strong> Total knee arthroplasty (TKA) is now a reliable treatment for osteoarthritis. The aim of this study was to study the clinical and functional outcome of total knee arthroplasty using knee society score and to find association between knee functional score and knee clinical score.</p><p class="abstract"><strong>Methods:</strong> We conducted a prospective analysis of 40 cases of osteoarthritis knee patients at a tertiary care centre in Mumbai over a period of two years. Those patients who underwent total knee arthroplasty were assessed clinically and functionally using knee society score.<strong></strong></p><p class="abstract"><strong>Results:</strong> The mean preoperative knee clinical score (KCS) was 49.40±13.79 which was increased to a postoperative score of 86.08±5.64 at the end of 6 month. Similarly the mean preoperative knee functional score (KFS) was 32.75±11.79 which was increased to a postoperative score of 84.43±9.59 at the end of 6 month. There was significant increase in KCS and KFC score during follow up at 1, 3 and 6 month interval. There was significant association between knee functional score and knee clinical score at every interval.</p><p><strong>Conclusions:</strong> Total knee arthroplasty improves the functional ability of the patient and the ability of the patient to get back to pre-disease state, which is to have a pain free mobile joint, as reflected by the improvement in the post-op knee clinical score and knee functional score.</p>

Guided Imagery for Total Knee Replacement: A Randomized, Placebo-Controlled Pilot Study.

To determine the effect of guided imagery (GI) on functional outcomes of total knee replacement (TKR), explore psychological and neuroimmune mediators, and assess feasibility of study implementation. Investigator-blinded, randomized, placebo-controlled pilot study. Hospital, surgeon's office, participant's home. 82 persons undergoing TKR. Audiorecordings of TKR-specific GI scripts or placebo-control audiorecordings of audiobook segments. Gait velocity and Western Ontario and McMaster Universities Arthritis Index (WOMAC) Function scale. Outcomes for 58 participants (29 receiving GI and 29 controls) were analyzed at 6 months after surgery. The most frequent reason for noncompletion was protocol-driven exclusion at 6 months for having the contralateral knee replaced before the study endpoint (n = 15). With imaging ability as a moderator, gait velocity, but not WOMAC Function score, was significantly improved at 6 months in the GI group. Participants in the GI group, but not the control group, had lower WOMAC Pain scores at 3 weeks after surgery than at baseline. Hair cortisol concentration was significantly lower at 6 months after surgery than at baseline in the GI group but not the control group. GI group participants had lower treatment adherence but greater treatment credibility than the control group. Randomized controlled trials of GI in the TKR population are feasible, but inclusion/exclusion criteria influence attrition. Further studies are needed to elaborate this study's findings, which suggest that guided imagery improves objective, but not patient-reported, outcomes of TKR. Hair cortisol concentration results suggest that engagement in a time-limited guided imagery intervention may contribute to stress reduction even after the intervention is terminated. Further investigation into optimal content and dosing of GI is needed.

Outcome of Total Knee Replacement via Two Approaches in Indian Scenario.

This study was designed to assess the early and late clinical and functional outcome based on Knee Society Score in patients undergoing total knee replacement (TKR) by medial parapatellar approach/midvastus approach. A total of 52 patients were included in the study of whom 28 patients were operated by medial parapatellar approach and 24 by midvastus approach. Patients were assessed on the basis of Knee Society Score, along with other parameters such as duration of hospital stay, blood loss during, and after surgery. The patients were followed up at 2 weeks, 6 weeks, 3 months, 6 months, and 1 year. The knee objective score showed significant better scores in midvastus group at 2 weeks, 6 weeks, and 3 months, but the score in both the groups was not significant at 6 months and 1 year. The knee functional score showed significant better score in midvastus group at the end of 2 and 6 weeks. However, score in both the groups was not significant by the end of 3 months, 6 months, and 1 year. Patients' satisfaction and expectation scores were similar in both groups at all time intervals. The functional outcome of TKR surgery by midvastus approach was better in the first 3 months in comparison to medial parapatellar approach.

Evaluation of Outcomes of Total Knee Replacement with and without a Navigation System

The aim of this study was to compare the results of TKA performed with the use of a navigation system vs. conventional knee arthroplasty and to evaluate the effectiveness of navigation system support in TKA. We evaluated patients undergoing TKA for osteoarthritis in the years 2011-2013. Columbus prostheses were implanted in 84 knees. Group 1 included patients in whom TKA was performed with the use of the OrthoPilot Navigation System, and Group 2 was a control group of patientsundergoing conventional TKA. Group 1 ultimately comprised 30 patientsat a mean age of 71.8 years, while Group 2 consisted of 30 patients at a mean age of 73.5 years. Radiographic parameters were evaluated according to the mechanical axis of the leg. Clinical evaluation relied on the VAS and KSSscores. Mean operation time was 94 minutes in Group 1.It was shorter in Group 2, with a mean of 75 minutes. Postoperative VAS scores did not differ betweenthe groups. Significant improvement was noted between pre- and postoperative in KSS scores in both groups. The control group showed more valgus mechanical axis deviation than varus deviation. In experienced hands, navigated surgery time may be similar to that of conventional TKA and give superior results, both clinical and radiographic.

Patient-based outcome analysis is important to determine the success of total knee arthroplasty: result of a focus group discussion.

BackgroundTotal knee replacement (TKR) results in an excellent outcome in terms of pain relief. The reporting of outcomes was traditionally focused on implant survivorship and objective outcomes such as range of motion, knee stability, and radiographic alignment. However, patients and doctors had differing perceptions of all domains of outcome, especially subjective quality of life domains such as emotions and social functioning. In this study, we tried to find out the expectations of Indian patients regarding TKR and assess the level of satisfaction among our patients from their view point using focus group discussion (FGD), and whether these expectations have an impact on outcomes and patient satisfaction.Materials and methodsThis study was conducted in the Department of Orthopedics, Government Medical College, Kozhikode, Kerala, India, in November 2014. Patients between the ages 60 and 65 years who met inclusion criteria were selected. A total of 50 patients were selected for FGDs. Among them, 42 patients participated in FGD. The remaining eight did not appear for the discussion. A total of four FGD sessions were conducted.Results and discussionIt was found that there is a discrepancy between the satisfaction levels of patient and surgeon. There is a difference in satisfaction level achieved depending on socioeconomic, geographic, and cultural characteristics.ConclusionNewer methods of TKR outcome assessment combining radiological outcome, surgeon-based assessment, and patient satisfaction based on their socioeconomic status and cultural characteristics should be developed for different populations.

Evaluation of results of total knee replacement by computer assisted navigation and conventional techniques

Introduction: Accurate component implantation and eventually the overall limb alignment are the essential requirements of a successful knee arthroplasty. Computer assisted navigation came into vogue with a claim of precision in aligning the limb as compared with the conventional jig based technique. This retrospective study evaluates the results of fifteen cases of total knee arthroplasty performed by the conventional technique and five cases, by the computer assisted navigation. Methods: This retrospective study was carried out at Ayushman hospital and Chirayu medical college, Bhopal from1993 to 2014. All patients selected, were suffering from tri -compartmental osteoarthritis of the knees having severe pain and varus deformity, except one who had post traumatic secondary osteoarthritis.. In fifteen cases total knee arthroplasty was done by using the jig based conventional technique whereas computer assisted navigation was used in five cases. Results: Intraoperatively less blood loss and a comparatively comfortable immediate post operative period were observed. However there was no appreciable advantage noticed in the long term results. Conclusion: Computer navigation by virtue of its feedback on screen during the surgery helped, to improve the accuracy of aligning the mechanical axis, whereas in the conventional jig based surgery, dependence was entirely on visual perception of the angles and cuts.

Outcome of total knee replacement following explantation and cemented spacer therapy.

Background: Infection after total knee replacement (TKR) is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation.Patients and methods: A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient’s group comprised of 53% (18) males and 47% (16) females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years). We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. Results: We reported 31.4% (11) reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation) after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation) after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation.Conclusion: No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation. Our data point out to the fact that a longer time interval between explantation and re-implantation reduces the rate of reinfection. From our point of view, the optimal timing for re-implantation depends on various specific factors and therefore it should be defined individually.

Early failure with the Journey-Deuce bicompartmental knee arthroplasty.

The aim of this study was to evaluate the early functional outcome and survivorship of a bicompartmental knee arthroplasty implant (Journey-Deuce) in a cohort of patients with combined medial and patellofemoral degenerative osteoarthritis. Fifteen patients with a mean age of 57years were followed up prospectively and evaluated with clinical examination, Oxford knee score and radiology imaging. Poor pain scores, concerns about the tibial fixation, early aseptic loosening of the tibial component and a revision rate of 60% at a minimum follow-up of 54months are reported. Implantation of this prosthesis was stopped at our institution well before the first revision due to an unfavourable early clinical response. This was further endorsed by an unacceptable revision rate. The outcome of the Journey-Deuce bicompartmental knee replacement was considerably worse than the published outcome of total knee replacement.

Influence of somatization and depressive symptoms on the course of pain within the first year after uncomplicated total knee replacement: a prospective study

Approximately 10-25% of patients are reportedly dissatisfied with the results of bicondylar knee prosthesis implantation. The purpose of this study was to evaluate the effect of depressive symptoms and particularly somatization dysfunction on outcomes after total knee replacement (TKR). One hundred fifty patients were enrolled in this prospective study. Pre-operatively, depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9) and somatization was assessed using the PHQ-15. The primary outcome measure was self-assessed knee function evaluated with the Knee Osteoarthritis Outcome Score (KOOS). Pain was measured on a numerical rating scale (NRS). The secondary outcome measures were the KOOS subscales and patient satisfaction. Intergroup differences were tested using an independent t-test. The odds ratio was used to determine the probability of an unsatisfactory outcome. At 12months post-operatively, patients with depressive symptoms and particularly patients with somatization dysfunction usually had a significantly higher NRS score at rest and during activities, a lower knee function before and after surgery, and higher dissatisfaction. Psychopathologic factors, particularly somatization dysfunction, have an impact on TKR outcomes. Preoperative screening and concurrent treatment of the diagnosed psychological disorder may improve patient-perceived outcomes.

Prosthetic alignment after total knee replacement is not associated with dissatisfaction or change in Oxford Knee Score: A multivariable regression analysis

BackgroundApproximately 18% of the patients are dissatisfied with the result of total knee replacement. However, the relation between dissatisfaction and prosthetic alignment has not been investigated before. MethodsWe retrospectively analysed prospectively gathered data of all patients who had a primary TKR, preoperative and one-year postoperative Oxford Knee Scores (OKS) and postoperative computed tomography (CT). The CT protocol measures hip–knee–ankle (HKA) angle, and coronal, sagittal and axial component alignment. Satisfaction was defined using a five-item Likert scale. We dichotomised dissatisfaction by combining ‘(very) dissatisfied’ and ‘neutral/not sure’. Associations with dissatisfaction and change in OKS were calculated using multivariable logistic and linear regression models. Results230 TKRs were implanted in 105 men and 106 women. At one year, 12% were (very) dissatisfied and 10% neutral. Coronal alignment of the femoral component was 0.5 degrees more accurate in patients who were satisfied at one year. The other alignment measurements were not different between satisfied and dissatisfied patients. All radiographic measurements had a P-value>0.10 on univariate analyses. At one year, dissatisfaction was associated with the three-months OKS. Change in OKS was associated with three-months OKS, preoperative physical SF-12, preoperative pain and cruciate retaining design. DiscussionNeither mechanical axis, nor component alignment, is associated with dissatisfaction at one year following TKR. Patients get the best outcome when pain reduction and function improvement are optimal during the first three months and when the indication to embark on surgery is based on physical limitations rather than on a high pain score. Level of evidence2

Results and outcomes of total knee replacement in osteoarthritis patients

Results and outcomes of total knee replacement in osteoarthritis patients

Effectiveness of structured exercise program on the functional outcomes in total knee replacement

Background: Total knee replacement (TKR) surgery has become the most successful surgery for patients with severe debilitating arthritis. Numerous factors influence the outcomes in TKR Post-operative physiotherapy and rehabilitation greatly influences the outcome of TKR. Despite the high incidence of TKR in recent years there is no post-operative rehabilitation approach being incorporated correctly to address the muscular and functional deficits following surgery. Objective: The main objective of the study is to analyze the effectiveness of structured rehabilitation program on the functional outcome of patients following total knee replacement. Materials & Methods: All patients who were planned to undergo elective primary TKR were recruited. Subjects posted for revision TKR, rheumatoid arthritis posted for TKR, immediate post-operative complications like deep vein thrombosis, signs of infection, TKR for Post-fracture cases were excluded. Eighty subjects enrolled for the study were randomly allocated to control and experimental group using simple random sampling. The control group receives standard care and experimental group receive structured exercise program comprising range of motion, staged training of quadriceps, vastus medialis strengthening exercises, early balance training and functional retraining. Outcomes including pain severity, knee joint mobility, isometric muscle strength, six minute walk test and functional outcome using KOOS scale were measured post-surgery and after 3 months follow up. Results: In experimental group, follow up measures of pain severity (p-.0001), knee joint extension range (p-.0016), isometric strength of hamstrings (p-0008) shows statistically significant results than control group. Whereas, in experimental group, follow up measures of knee flexion range (p-< .0001), isometric strength of quadriceps (p-

The utilization of smart trials in PCL retaining knees

Technical issues such as instability, mal-rotation, and mal-alignment continue to be issues leading to total knee replacement revision. Soft tissue balancing is critical to successful address these issues for successful total knee replacement outcomes. Intra-op sensors can now be used to dynamically balance knees in real time and mitigate negative outcomes.

Acceptability of a Guided Imagery Intervention for Persons Undergoing a Total Knee Replacement.

Guided imagery (GI) has been recommended as a mind-body therapy for pain relief following orthopaedic surgery, but little is known about the acceptability of the intervention. Describe the perceptions of patients undergoing total knee replacement (TKR) surgery regarding the acceptability of a customized GI intervention to promote TKR outcomes. Narrative and survey data collected during a randomized controlled trial of the GI intervention were analyzed to assess the acceptability of the intervention. Most participants were satisfied with and actively engaged in the intervention, and they perceived it to be helpful. For the smaller group of participants who did not find the intervention to be acceptable, reasons for dissatisfaction and barriers to engagement were identified. Guided imagery is an acceptable intervention for many persons undergoing TKR surgery. The results of this study can provide information to further develop a targeted and customized GI intervention for this population.

Early outcome after total knee replacement using computed tomography-based patient-specific cutting blocks versus standard instrumentation.

To compare early outcome of total knee replacement (TKR) using computed tomography (CT)-based patient-specific cutting blocks versus standard instrumentation. 40 men and 44 women (90 knees) aged 45 to 88 (mean, 65) years who underwent TKR using standard instrumentation were compared with 39 men and 43 women (90 knees) aged 44 to 85 (mean, 64) years who underwent TKR using CT-based patient-specific cutting blocks. A single surgeon performed all TKRs through the medial parapatellar approach using a cemented prosthesis, with the posterior cruciate ligament retained and the patella resurfaced. Respectively in the standard and patient-specific instrumentation groups, 74 and 70 patients were followed up for a mean of 30 and 14 months. The mean Oxford Knee Score was 19 and 19 preoperatively, 34 and 34 at 3 months, and 37 and 40 at 12 months (p=0.02). 71% and 88% of patients achieved good-to-excellent outcome (Oxford Knee Score of >34) at 12 months (p=0.008). The respective mean EQ-5D score was 54 and 52 preoperatively, 73 and 76 at 3 months, and 77 and 78 at 12 months. 18% and 2% of patients required a blood transfusion (p=0.0002), with a mean blood loss of 292 and 254 g/l (p=0.049). The mean tourniquet time was 45 minutes in both groups. There was no infection or revision in either group. Compared with standard instrumentation, the use of CT-based patient-specific cutting blocks for TKR achieved higher Oxford Knee Score at 12 months and lower blood loss and transfusion rate.