A Randomized, Controlled Trial of Total Knee Replacement.

BACKGROUND: More than 670,000 total knee replacements are performed annually in the United States; however, high-quality evidence to support the effectiveness of the procedure, as compared with nonsurgical interventions, is lacking. METHODS: In this randomized, controlled trial, we enrolled 100 patients with moderate-to-severe knee osteoarthritis who were eligible for unilateral total knee replacement. Patients were randomly assigned to undergo total knee replacement followed by 12 weeks of nonsurgical treatment (total-knee-replacement group) or to receive only the 12 weeks of nonsurgical treatment (nonsurgical-treatment group), which was delivered by physiotherapists and dietitians and consisted of exercise, education, dietary advice, use of insoles, and pain medication. The primary outcome was the change from baseline to 12 months in the mean score on four Knee Injury and Osteoarthritis Outcome Score subscales, covering pain, symptoms, activities of daily living, and quality of life (KOOS4); scores range from 0 (worst) to 100 (best). RESULTS: A total of 95 patients completed the 12-month follow-up assessment. In the nonsurgical-treatment group, 13 patients (26%) underwent total knee replacement before the 12-month follow-up; in the total-knee-replacement group, 1 patient (2%) received only nonsurgical treatment. In the intention-to-treat analysis, the total-knee-replacement group had greater improvement in the KOOS4 score than did the nonsurgical-treatment group (32.5 vs. 16.0; adjusted mean difference, 15.8 [95% confidence interval, 10.0 to 21.5]). The total-knee-replacement group had a higher number of serious adverse events than did the nonsurgical-treatment group (24 vs. 6, P=0.005). CONCLUSIONS: In patients with knee osteoarthritis who were eligible for unilateral total knee replacement, treatment with total knee replacement followed by nonsurgical treatment resulted in greater pain relief and functional improvement after 12 months than did nonsurgical treatment alone. However, total knee replacement was associated with a higher number of serious adverse events than was nonsurgical treatment, and most patients who were assigned to receive nonsurgical treatment alone did not undergo total knee replacement before the 12-month follow-up. (Funded by the Obel Family Foundation and others; MEDIC ClinicalTrials.gov number, NCT01410409.).

Serum 25-hydroxyvitamin D, calcium and parathyroid hormone levels in Native and European populations in Greenland.

Ca homoeostasis is important to human health and tightly controlled by powerful hormonal mechanisms that display ethnic variation. Ethnic variations could occur also in Arctic populations where the traditional Inuit diet is low in Ca and sun exposure is limited. We aimed to assess factors important to parathyroid hormone (PTH) and Ca in serum in Arctic populations. We included Inuit and Caucasians aged 50-69 years living in the capital city in West or in rural East Greenland. Lifestyle factors were assessed by questionnaires. The intake of Inuit diet was assessed from a FFQ. 25-Hydroxyvitamin D (25OHD2 and 25OHD3) levels were measured in serum as was albumin, Ca and PTH. The participation rate was 95 %, with 101 Caucasians and 434 Inuit. Median serum 25OHD (99·7 % was 25OHD3) in Caucasians/Inuit was 42/64 nmol/l (25, 75 percentiles 25, 54/51, 81) (P<0·001). Total Ca in serum was 2·33/2·29 mmol/l (25, 75 percentiles 2·26, 2·38/2·21, 2·36) (P=0·01) and PTH was 2·7/2·2 pmol/l (25, 75 percentiles 2·2, 4·1/1·7, 2·7) (P<0·001). The 69/97 Caucasians/Inuit with serum 25OHD <50 nmol/l differed in PTH (P=0·001) that rose with lower 25OHD levels in Caucasians, whereas this was not the case in Inuit. Ethnic origin influenced PTH (ß=0·27, P<0·001) and Ca (ß=0·22, P<0·001) in multivariate linear regression models after adjustment for age, sex, BMI, smoking, alcohol and diet. In conclusion, ethnic origin influenced PTH, PTH response to low vitamin D levels and Ca levels in populations in Greenland. Recommendations are to evaluate mechanisms underlying the ethnic influence on Ca homoeostasis and to assess the impact of transition in dietary habits on Ca homoeostasis and skeletal health in Arctic populations.

Knee Osteoarthritis Patients Can Provide Useful Estimates of Passive Knee Range of Motion: Development and Validation of the Copenhagen Knee ROM Scale.

BACKGROUND: Knee arthroplasty does not always require extensive long-term follow-up. If knee range of motion (ROM) could be assessed reliably by patients, some follow-up visits might be replaced by patient-reported outcome measures, and this additional information could be reported directly to registers. We developed and tested the validity and reliability of a simple scale for patients to self-report their passive knee ROM. METHODS: Through an iterative process, we created a 2-item scale with 11 illustrations of knee motion in 15° increments. The validity and reliability was tested in knee osteoarthritis and arthroplasty patients at different treatment stages, many with poor ROM. Patient estimates were compared to passive goniometer measurements performed blindly by a physiotherapist and a junior orthopedic surgeon. RESULTS: The mean difference between 100 patients' (70.9 years) estimates and goniometer measurements was -0.7° (standard deviation, 12.3°) for flexion and 1.1° (standard deviation, 11.6°) for extension, both not significant. Correlation was 0.79 and 0.63, and kappa values at retest were 0.84 and 0.66. For flexion < 110°, sensitivity of patient estimates was 88% and specificity was 88%. For a limit of 100°, values were 95% and 81%. For extension deficits >10°, sensitivity was 78% and specificity 70%. Values were 100% and 66% for a 15° limit. CONCLUSION: The Copenhagen Knee ROM Scale is a patient-friendly and feasible alternative to passive ROM measurement for registers, research, and selected clinical use. This scale appears reliable and valid compared to reports of similar tools, and patient estimates are better correlated to goniometer measurements.

Thresholds for the Oxford Hip Score after total hip replacement surgery: a novel approach to postoperative evaluation.

BACKGROUND: This is a prospective cohort study to define the thresholds to distinguish patients with a satisfactory or unsatisfactory outcome after total hip replacement (THR) based on patient-reported outcome measures (PROMs) including the Oxford Hip Score (OHS), and using patient satisfaction and patient-perceived function as global transition items. The thresholds are intended to be used as a tool in the process of determining which patients are in need of postoperative outpatient evaluation. METHODS: One hundred and three THR patients who had completed a preoperative questionnaire containing the OHS questionnaire were invited to complete the same questionnaire and supplementary questions at a mean of 6 (4-9) months after surgery. Correlations between outcome measures and anchors were calculated using Pearson's correlation coefficient. Thresholds were established by receiver operating characteristic (ROC) analysis, using multiple anchors. RESULTS: Significant correlations were found between outcome measures and anchors. Thresholds were determined for outcome measures coupled with satisfaction, patient-perceived function and a combination thereof using a cut-off of 50 and 70. CONCLUSIONS: We have established a set of thresholds for Oxford scores that may help determine which THR patients are in need of postoperative evaluation. These thresholds can be implemented in clinical practice. LEVEL OF EVIDENCE: Level 3.

Absence of a Tourniquet Does Not Affect Fixation of Cemented TKA: A Randomized RSA Study of 70 Patients.

We aimed to determine whether not using a tourniquet in cemented TKA would affect migration of the tibial component measured by radiosterometric analysis (RSA). Seventy patients were randomized into a tourniquet group and a non-tourniquet group and using model-based RSA, the migration of the tibial component was analyzed. Primary and secondary outcome measures were maximum total point motion (MTPM) and translations and rotations. Follow-up period was 2 years. The tibial component was well fixated in both groups and no significant difference in migration between the two groups was detected (P=0.632). Mean MTPM (SD) was 0.47 mm (0.16) in the tourniquet group and 0.45 mm (0.21) in the non-tourniquet group. Absence of tourniquet indicates that stable fixation of the tibial component can be achieved in cemented TKA.

Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability.

Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective 10-year RSA. This is the first evaluation of the multicenter cohort after 3-years. All patients received E-XLPE liners (E1, Biomet) and porous-titanium coated cups (Regenerex, Biomet). There was no difference (P=0.450) in median femoral head penetration into the E-XLPE liners at 3-years comparing cobalt-chrome heads (-0.028mm; inter-quartile range (IQR) - 0.065 to 0.047) with ceramic heads (-0.043mm, IQR - 0.143to0.042). The 3-year follow-up indicates minimal E-XLPE liner penetration regardless of head material and minimal early cup movement.

Faster recovery without the use of a tourniquet in total knee arthroplasty.

BACKGROUND AND PURPOSE: Tourniquet application is still a common practice in total knee arthroplasty (TKA) surgery despite being associated with several adverse effects. We evaluated the effects of tourniquet use on functional and clinical outcome and on knee range of motion (ROM). PATIENTS AND METHODS: 70 patients who underwent TKA were randomized into a tourniquet group (n = 35) and a non-tourniquet group (n = 35). All operations were performed by the same surgeon and follow-up was for 1 year. Primary outcomes were functional and clinical outcomes, as evaluated by KOOS and knee ROM. Secondary outcomes were intraoperative blood loss, surgical time and visibility, postoperative pain, analgesic consumption, and transfusion requirements. RESULTS: Patients in the non-tourniquet group showed a better outcome in all KOOS subscores and better early knee ROM from surgery to week 8. No difference was detected at the 6- and 12-month follow-ups. Postoperative pain and analgesic consumption were less when a tourniquet was not used. Surgical time and visibility were similar between groups. Intraoperative blood loss was greater when not using a tourniquet, but no postoperative transfusions were required. INTERPRETATION: This study shows that TKA without the use of a tourniquet results in faster recovery in terms of better functional outcome and improved knee ROM. Furthermore, reduced pain and analgesic use were registered and no intraoperative difficulties were encountered.

Danish surgeons allow the most athletic activities after total hip and knee replacement.

BACKGROUND AND PURPOSE: Counselling patients for or against athletic activities after well performed total hip arthroplasty (THA) and total knee arthroplasty (TKA). Level of evidence is low, and the current international guidelines are based on North American expert opinions in 2001 and 2008. Could technical and operative development and social or cultural differences apply for different counselling? METHODS: All Danish experts in head of departments performing more than 100 THAs or TKAs per year, were invited to fill in a questionnaire regarding the most popular sport activities in the Danish 60-69 years old population RESULTS: Response rate was 74 and 89% for the TKA and THA departments, respectively. A pronounced variation between the departments was observed and compared to the latest published US recommendations in 2007, the present Danish recommendations are significantly more liberal. Athletic activities are now allowed by 87% of the Danish arthroplasty departments. Of these 55% allow for high-impact activities after THA compared to 21% in US in 2007 (p < 0.0001). Recommendations for TKA patients are less liberal. Only 38% of the departments allow for high-impact activities after TKA compared to the 55% after THA (p < 0.0001). INTERPRETATION: Based on the pronounced variation between departments and the fact that a highly significant trend was observed over 5 years on an undocumented basis it was concluded that there is an imminent need for a higher scientific level on this issue­which hopefully can develop in a few years using PROMs in large scale follow-up studies.

No superior performance of hydroxyapatite-coated acetabular cups over porous-coated cups.

BACKGROUND AND PURPOSE: Hydroxyapatite (HA) coating is believed to improve bone-implant ingrowth and long-term survival of prostheses. Recent studies, however, have challenged this view. Furthermore, HA particles may produce third-body wear and initiate aseptic loosening of implants. We report the performance of HA- and porous-coated acetabular cups in a prospective randomized trial. METHODS: This was an 8-year follow-up study of our previously published prospective randomized study to compare clinical outcomes, survival, periprosthetic bone mineral density, migration, and wear rates of HA- and porous-coated acetabular cups. Dual X-ray absorptiometry (DXA) and Ein Bild Roentgen Analyse (EBRA) measurements were used. 100 patients who underwent unilateral cementless total hip arthroplasty were randomized to either porous-coated cups or HA-coated cups. Patients were examined preoperatively and at 3, 6, and 9 months, and also 1, 3, and 8 years after surgery. 81 patients were available for 8-year follow-up, 40 with porous-coated cups and 41 with HA-coated cups. RESULTS: Age, sex, bone mineral density, and clinical results (Harris hip score) were similar in the 2 groups. The survival, wear, and migration patterns of the cups were also similar in both groups. The results of periprosthetic bone mineral density scans in region of interest 2 was in favor of the porous-coated cups, but there were no differences between the 2 groups in all the remaining regions of interest. INTERPRETATION: HA coating had no statistically significant effect on clinical results, survival, wear, or migration at the 8-year follow-up.

Total knee replacement plus physical and medical therapy or treatment with physical and medical therapy alone: a randomised controlled trial in patients with knee osteoarthritis (the MEDIC-study).

BACKGROUND: There is a lack of high quality evidence concerning the efficacy of total knee arthroplasty (TKA). According to international evidence-based guidelines, treatment of knee osteoarthritis (KOA) should include patient education, exercise and weight loss. Insoles and pharmacological treatment can be included as supplementary treatments. If the combination of these non-surgical treatment modalities is ineffective, TKA may be indicated. The purpose of this randomised controlled trial is to examine whether TKA provides further improvement in pain, function and quality of life in addition to optimised non-surgical treatment in patients with KOA defined as definite radiographic OA and up to moderate pain. METHODS/DESIGN: The study will be conducted in The North Denmark Region. 100 participants with radiographic KOA (K-L grade ≥2) and mean pain during the previous week of ≤ 60 mm (0-100, best to worst scale) who are considered eligible for TKA by an orthopaedic surgeon will be included. The treatment will consist of 12 weeks of optimised non-surgical treatment consisting of patient education, exercise, diet, insoles, analgesics and/or NSAIDs. Patients will be randomised to either receiving or not receiving a TKA in addition to the optimised non-surgical treatment. The primary outcome will be the change from baseline to 12 months on the Knee Injury and Osteoarthritis Outcome Score (KOOS)(4) defined as the average score for the subscale scores for pain, symptoms, activities of daily living, and quality of life. Secondary outcomes include the five individual KOOS subscale scores, EQ-5D, pain on a 100 mm Visual Analogue Scale, self-efficacy, pain pressure thresholds, and isometric knee flexion and knee extension strength. DISCUSSION: This is the first randomised controlled trial to investigate the efficacy of TKA as an adjunct treatment to optimised non-surgical treatment in patients with KOA. The results will significantly contribute to evidence-based recommendations for the treatment of patients with KOA. TRIAL REGISTRATION: Clinicaltrials.gov reference: NCT01410409.

The Role of Preoperative Radiologic Severity, Sensory Testing, and Temporal Summation on Chronic Postoperative Pain Following Total Knee Arthroplasty.

OBJECTIVES: Knee osteoarthritis (KOA) can be associated with local and central sensitization. As an indicator of the central gain, facilitated temporal summation of pain (TSP) has been found in KOA patients. This facilitation is predictive of the development of chronic postoperative pain after total knee arthroplasty (TKA). Other studies have suggested hypoesthesia/hypoalgesia to thermal stimuli as a feature in KOA. This study investigated associations between preoperative TSP, thermal sensitivity, and radiologic severity for the development of chronic postoperative pain after TKA. METHODS: Radiologic KOA (Kellgren and Lawrence), TSP, and thermal stimuli were collected, preoperatively. Clinical knee pain intensity (VAS 0-10) was assessed before and 12 months following TKA. Patients were categorized into a chronic postoperative pain group if they experienced <30% pain reduction of the initial pain after 12 months. RESULTS: In total, 19% of the patients were categorized as chronic pain patients and presented facilitated preoperative TSP (P<0.05) and a trend towards increased heat pain threshold (P=0.077) compared with patients with normal recovery. Pearson correlations found that preoperative TSP (R=0.193; P=0.013), Kellgren and Lawrence (R=-0.168; P=0.027), warm detection threshold (R=0.195; P=0.012), and heat pain threshold (R=0.196; P=0.012) were associated with pain intensity 12 months after TKA where TSP was identified as an independent factor. DISCUSSION: This study showed that preoperatively facilitated TSP in KOA patients was predictive of the development of chronic postoperative pain following TKA. Furthermore, this study is the first to find an association between preoperative hypoalgesia to heat and the development of chronic postoperative pain following TKA.

Bone remodelling of the proximal femur after total hip arthroplasty with 2 different hip implant designs: 15 years follow-up of the thrust plate prosthesis and the Bi-Metric stem.

INTRODUCTION: The thrust plate prosthesis (TPP) was introduced to preserve bone in patients undergoing total hip arthroplasty. We assessed the long-term results of hip arthroplasty in patients who received the TPP compared to a traditional intramedullary stem (Bi-Metric). METHODS: In this prospective observational cohort study, we evaluated bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA), radiological imaging and clinical outcome using Harris Hip Score (HHS). Twenty patients received the TPP (group A) and 18 patients received the Bi-Metric stem (group B). Baseline was the 1st postoperative day, and subsequent follow-up was performed at 6 months, 1, 2, 8, 12 and 15 years after surgery. A four regions of interest (ROI) protocol was developed to assess BMD. RESULTS: In ROI1, bone resorption was significantly higher for group A at 6 months with a mean difference of 10% (95% confidence interval [CI], 4-16; p = 0.003) and 8% (95% CI, 1-15; p = 0.03) at 8 years. Regarding ROI4, group A had a lesser decrease in general compared to group B. The radiological findings did not reveal any subsidence or detectable implant migration. HHS improved from 53 (23-69) to 93 (55-100) in group A and from 51 (24-72) to 94 (78-100) in group B. CONCLUSION: The TPP was not found to be inferior to the Bi-Metric stem regarding bone preservation. The decrease in BMD in ROI4 was greater in group B. Clinical and radiological results also revealed that the TPP was not inferior to the Bi-Metric stem.

Age Interactions on Pain Sensitization in Patients With Severe Knee Osteoarthritis and Controls.

OBJECTIVES: Widespread pressure hyperalgesia, facilitated temporal summation of pain (TSP), and impaired conditioned pain modulation (CPM) have been found in knee osteoarthritis (KOA) patients compared with controls and these parameters have further been suggested to be altered in the elderly. This study investigated the influence of age on pressure hyperalgesia, TSP, and CPM in patients with KOA and controls. MATERIALS AND METHODS: One hundred thirty-three severe KOA patients and 50 age-matched and sex-matched asymptomatic controls were assessed by cuff algometry and handheld pressure algometry. Pain sensitivity was assessed around the head of the gastrocnemius muscle to identify mild pain detection threshold (MPDT) and pressure tolerance threshold (PTT). TSP was assessed by visual analogue scale scores of the pain evoked by 10 repetitive cuff stimulations. CPM was assessed as the difference in PTT before and during cuff-induced tonic arm pain. Pressure pain thresholds (PPTs) were assessed by handheld algometry at the tibialis anterior muscle. Two subgroups were analyzed in the age range below and above 65 years. Pearson correlations between age and pain parameters were applied. RESULTS: Patients demonstrated reduced MPDT, PTT, and PPT (P<0.01), facilitated TSP (P<0.02), and a trend toward impaired CPM (P=0.06) compared with controls. A negative correlation was found between MPDT, PTT, and PPT and age (P<0.05) but no age-related association was found for TSP and CPM. DISCUSSION: Pressure hyperalgesia was affected by age whereas dynamic pain mechanisms such as TSP and CPM were unaffected suggesting that these parameters are robust for a larger age range and reliable for long-term follow-up studies.

Criteria used when deciding on eligibility for total knee arthroplasty--Between thinking and doing.

BACKGROUND: Clinical decision-making in total knee arthroplasty (TKA) is a complex process needing further clarification. The aim of this study was to compare TKA eligibility criteria considered most important by orthopedic surgeons (OSs) to characteristics of patients with knee osteoarthritis (OA) eventually found eligible for TKA. METHODS: Nine OSs chose the five criteria most important when deciding on TKA eligibility. Cross-sectional data from 200 patients found either eligible (n=100) or not eligible (n=100) for TKA by one of the nine OS, were analyzed in a regression analyses with TKA eligibility as the dependent variable. RESULTS: Radiographic severity (n=8), pain (n=9), functional disability (n=8) and not responding to the recommended non-surgical treatment (n=7) were considered most important by OSs. Associations (P<0.25) between TKA eligibility and criteria found important by the OS were demonstrated for worse radiographic severity and more functional limitations, but not for pain and not responding to the recommended non-surgical treatment. Furthermore, more comorbidities and higher Body Mass Index (BMI) were associated with TKA-eligibility, but not found important for TKA eligibility by the OS. CONCLUSION: Radiographic severity and functional limitations were confirmed as drivers for TKA eligibility, while pain was not. Not responding to non-surgical treatment was not included in the decision-making, suggesting low uptake of clinical guidelines in clinical practice. This study highlights the complexity of the decision-making with some overlap between the criteria that OSs think they apply and what is actually applied in clinical practice.

DXA scanning of acetabulum in patients with cementless total hip arthroplasty.

The aim of this study was to evaluate the reproducibility of bone mineral density (BMD) measurements of the periprosthetic bone in patients with hemispherical acetabular cups in cementless total hip arthroplasty (THA). Thirty patients were treated for primary osteoarthrosis with cementless THA. Dual-energy X-ray absorptiometry (DXA) scanning was performed with a pencil-beam bone densitometer (Norland XR-36). Accuracy and reproducibility was determined by double measurements of BMD in four regions of interest (ROI). The influence of patient postures including various pelvic inclination angles was evaluated as well. Pitman test for a combined netROI revealed a standard deviation ratio of 3.2 for the anterio-posterior scans related to the lateral position. The Wilkinson ROIs showed a high intraobserver agreement. With pelvic tilt increasing until 20 degrees , the precision of DXA scanning decreased. In conclusion, reproducibility of DXA scanning was high. This study demonstrated that the patients can be scanned in the supine position, and BMD measurement of the periacetabular bone can be performed using the Wilkinson model with four rectangular ROIs.

Chronic postoperative pain after primary and revision total knee arthroplasty.

OBJECTIVES: Clinical experience suggests that patients with osteoarthritis (OA) undergoing revision total knee arthroplasty (TKA) experience more chronic complications after surgery compared with patients receiving primary TKA. This study aimed to investigate the difference in pain, mobility, and quality of life (QoL) in patients after revision TKA compared with patients after primary TKA. METHODS: A total of 99 OA patients after revision TKA surgery and 215 patients after primary TKA surgery were investigated in a cross-sectional study using: a pain description of current pain (non-existent, mild, moderate, severe, or unbearable), the pain intensity visual analogue scale, the Knee Society Score, and the Osteoarthritis Research Society International questionnaire. RESULTS: Nineteen percent after primary TKA surgery and 47% after revision TKA surgery experienced severe to unbearable chronic postoperative pain. After revision TKA surgery patients reported higher pain intensities during rest (P=0.039), while walking (P=0.008), and on average over the last 24 hours (P=0.050) compared with the patients after primary TKA surgery. Patients after revision TKA surgery had reduced walking distance (P=0.001), increased use of walking aids (P=0.015), and showed an overall decreased QoL (P<0.001) compared with patients after primary TKA surgery. No significant improvement was found in walking distance (P=0.448) for patients before revision TKA surgery compared with after revision TKA surgery. DISCUSSION: More than twice as many patients have pain after revision surgery compared with patients after primary TKA. Patients after revision TKA surgery have reduced function, poorer QoL, and higher pain intensity compared with patients after primary TKA surgery.

Widespread sensitization in patients with chronic pain after revision total knee arthroplasty.

Pain and sensitization are major issues in patients with osteoarthritis both before and after total knee arthroplasty (TKA) and revision TKA (re-TKA). The aim of this study was to assess sensitization in patients with and without chronic pain after re-TKAs. Twenty patients with chronic knee pain and 20 patients without pain after re-TKA participated. Spreading of pain was evaluated as the number of pain sites using a region-divided body chart. The pressure pain threshold (PPT) and pressure pain tolerance (PTT) were assessed by cuff algometry at the lower leg. Temporal summation of pain was assessed by recordings of the pain intensity on a visual analog scale (VAS) during repeated cuff pressure stimulations. Conditioning pain modulation (CPM) was recorded by experimental tonic arm pain by cuff pressure stimulation and assessment of PPTs on the knee, leg, and forearm using handheld pressure algometry. Participants with pain after re-TKA compared to participants without pain demonstrated: (1) significantly more pain sites (P=.004), (2) decreased cuff PPTs and PTTs at the lower leg (P<.001), (3) facilitated temporal summation (P<.001), and (4) impaired CPM (P<.001). Additionally, significant correlations between knee pain intensity and cuff PPTs, temporal summation, and CPM and between total duration of knee pain and temporal summation were found (P<.05). This study demonstrated widespread sensitization in patients with pain after re-TKA and highlighted the importance of ongoing nociceptive input for the chronification process. This has important implications for future revisions, and precautions should be taken if patients have widespread sensitization.