Abnormal quantitative sensory testing is associated with persistent pain one year after TKA.

BACKGROUND: Up to 15% of patients report at least moderate persistent pain after TKA. Such pain may be associated with the presence of widespread hyperalgesia and neuropathic-type pain. QUESTIONS/PURPOSES: We asked if there was a difference among patients who report moderate to severe pain or no pain at least 12 months after TKA regarding (1) pressure pain threshold, (2) thermal (cold/heat) pain and detection thresholds, and (3) self-reported neuropathic pain. PATIENTS AND METHOD: Fifty-three volunteers were recruited from patients reporting no pain or moderate to severe pain, according to the Knee Society Score©. Differences between the moderate-to-severe and no-pain groups regarding pressure pain, heat and cold thresholds, and self-reported neuropathic-type pain were analyzed using independent t-tests. RESULTS: Patients in the moderate-to-severe pain group exhibited reduced pressure pain threshold in the knee with the TKA (p=0.025) and at the elbow (p=0.002). This group also showed greater pain sensitivity to cold at the knee (p=0.008) and elbow (p=0.010), and increased heat pain sensitivity at the elbow (p=0.032). Cold and heat detection thresholds were impaired in this group at the elbow (cold, p=0.034; heat, p=0.010), although only heat detection was impaired at the knee (p=0.009). The moderate-to-severe pain group also reported more neuropathic-type pain (p=0.001). CONCLUSION: Persistent pain after TKA was associated with widespread pressure, cold hyperalgesia, and greater neuropathic-type pain. LEVEL OF EVIDENCE: Level III, prognostic study.

Functional outcomes comparing Triathlon versus Duracon total knee arthroplasty: does the Triathlon outperform its predecessor?

PURPOSE: Total knee arthroplasty (TKA) prosthesis designs are constantly evolving to obtain greater functional performance. The aim of this study is to compare the functional outcomes between the newer single radius (SR) Triathlon prosthesis with its multiradius (MR) predecessor the Duracon. METHOD: We analysed 1,012 primary TKA procedures which used either the Triathlon SR prosthesis or the Duracon MR prosthesis (338 Triathlon, 674 Duracon). Patients were assessed using the Knee Society score (KSS), range of movement measurements, pain and walking assessments at time points pre-operatively, one year and two years postoperatively. RESULTS: Both groups were similar pre-operatively in terms of age, gender and body mass index (BMI). At one year postoperatively the Triathlon group had a significantly better flexion (P = 0.005) and KSS (function score P = 0.037, knee score P = 0.000). At two years postoperatively the Triathlons had maintained a significantly better KSS (function score P = 0.046, knee score P = 0.000) and also knee flexion (P = 0.02). Pain assessments at two years were significantly better in the Triathlon group (P = 0.002) with 66.3 % of patients experiencing no pain at that point compared to 54.4 % with Duracon knees. CONCLUSION: This data supports the proposition that the use of Triathlon TKA results in improved outcomes for patients when compared to the Duracon TKA.

Stiffness after total knee arthroplasty: does component alignment differ in knees requiring manipulation? A retrospective cohort study of 281 patients.

This study aims to evaluate component alignment in a large cohort of total knee arthroplasties (TKAs) and ascertain whether alignment in TKAs undergoing postoperative manipulation under anesthetic is significantly different from those achieving good function. A retrospective review of 281 consecutive primary TKAs was performed. All TKAs underwent computed tomographic scanning (Perth computed tomography knee protocol). Of 281 TKAs, 21 (7.4%) underwent manipulation, performed at a mean of 8.1 weeks (range, 3-14 weeks) after surgery. No statistically significant difference was seen between groups for any of 12 parameters of alignment. Postoperative stiffness with the need for manipulation under anesthetic is multifactorial in origin. This study found insufficient evidence to support the theory that component alignment contributes significantly to the etiology of this difficult problem.

Computer navigation vs conventional total knee arthroplasty: five-year functional results of a prospective randomized trial.

Seventy-one patients were randomly allocated to undergo either computer-navigated or conventional arthroplasty. A statistically significant improvement in alignment was seen in the computer-navigated cohort. Five-year functional outcome was assessed using the Knee Society, Short Form-36, Western Ontario and McMaster Universities Osteoarthritis Index, and a patient satisfaction score. At 5 years, 46 patients were available for assessment (24 navigated and 22 conventional knees). No patients had undergone revision. No statistically significant difference was seen in any component of any measure of outcome between navigated and conventional cohorts. Longitudinal data showed function to be well maintained with no difference in functional score between 2 and 5 years in either cohort. Despite achieving better alignment, 5 years postoperatively, the functional outcome with computer-navigated knee arthroplasty appears to be no different to that implanted using a conventional jig-based technique.

Morbidity of navigated vs conventional total knee arthroplasty: a retrospective review of 327 cases.

A retrospective review of 146 patients undergoing navigated total knee arthroplasty (NTKA) and 181 patients undergoing conventional total knee arthroplasty (CTKA) was undertaken to establish whether NTKA, with its avoidance of intramedullary instrumentation, resulted in less early postoperative morbidity than CTKA. Cohorts were well matched in terms of age, sex, body mass index, and American Society of Anesthesiologists grade. Statistically significantly longer operative and tourniquet times were seen with NTKA. Blood transfusion requirements were significantly higher in CTKA. No statistically significant differences were seen in any other measure of postoperative morbidity (length of stay, hemoglobin drop, transfusion rate, postoperative anemia, time to achieve 70° flexion, and thromboembolic phenomena). In large, well-matched cohorts, NTKA offered no benefit in terms of early postoperative morbidity when compared with conventional jig-based techniques.

Three-dimensional component alignment and functional outcome in computer-navigated total knee arthroplasty: a prospective, randomized study comparing two navigation systems.

Computer navigation in total knee arthroplasty produces better component alignment than conventional techniques. Different navigation systems exist. We undertook a prospective, randomized study comparing 2 navigations systems (Stryker Full Navigation and Stryker Articular Surface Mounted [ASM] navigation systems). Three-dimensional component alignment (Perth computed tomographic knee protocol) and function at 1 year (Knee Society Scores) were assessed. Forty patients participated (20 fully navigated and 20 ASM-navigated total knee arthroplasties). Cohorts were well matched according to sex, age, and body mass index. No statistically significant difference was seen in any parameter of 3-dimensional component alignment or function between cohorts. Operative time for the ASM cohort was significantly less than the fully navigated cohort (P = .001). Both systems performed equally well, and therefore, surgeon preference should determine which system is used.

Variation in age and physical status prior to total knee and hip replacement surgery: a comparison of centers in Australia and Europe.

OBJECTIVE: To investigate whether variation exists in the preoperative age, pain, stiffness, and physical function of people undergoing total knee replacement (TKR) and total hip replacement (THR) at several centers in Australia and Europe. METHODS: Individual Western Ontario and McMaster Universities Osteoarthritis Index data (range 0-100, where 0 = best and 100 = worst) collected within 6 weeks prior to primary TKR and THR were extracted from 16 centers (n = 2,835) according to specified eligibility criteria. Analysis of covariance was used to evaluate differences in pain, stiffness, and physical function between centers, with adjustment for age and sex. RESULTS: There was marked variation in the age of people undergoing surgery between the centers (TKR mean age 67-73 years; F[6,1004] = 4.21, P < 0.01, and THR mean age 63-72 years; F[14,1807] = 7.27, P < 0.01). Large differences in preoperative status were observed between centers, most notably for pain (TKR adjusted mean pain 52.5-61.1; F[6,1002] = 4.26, P < 0.01, and THR adjusted mean pain 49.2-65.7; F[14,1802] = 8.44, P < 0.01) and physical function (TKR adjusted mean function 52.7-61.4; F[6,1002] = 5.27, P < 0.01, and THR adjusted mean function 53.3-71.0; F[14,1802] = 6.71, P < 0.01). Large effect sizes (up to 0.98) reflect the magnitude of variation between centers and highlight the clinical relevance of these findings. CONCLUSION: The large variations in age and preoperative status indicate substantial differences in the timing of joint replacement across the centers studied, with potential for compromised surgical outcomes due to premature or delayed surgery. Possible contributing factors include patient preferences, the absence of concrete indications for surgery, and the capacity of the health care systems.

Good alignment after total knee arthroplasty leads to faster rehabilitation and better function.

The aim of this study was to identify what aspects of implant alignment and rotation affect functional outcome after total knee arthroplasty (TKA). One hundred and fifty-nine total knee arthroplasties were performed at the authors' institution between May 2003 and July 2004. All patients underwent an objective and independent clinical and radiological assessment before and after surgery. A computed tomography scan was performed at 6 months. The alignment parameters that were measured included sagittal femoral, coronal femoral, rotational femoral, sagittal tibial, coronal tibial, and femorotibial mismatch. The cumulative error score, which represents the sum of the individual errors, was calculated. Functional outcome was measured using the Knee Society Score. Good coronal femoral alignment was associated with better function at 1 year (P = .013). Trends were identified for better function with good sagittal and rotational femoral alignment and good sagittal and coronal tibial alignment. Patients with a low cumulative error score had a better functional outcome (P = .015). These patients rehabilitated more quickly and their length of stay in hospital was 2 days shorter.

Does pain predict outcome in hips with osteonecrosis?

It generally is accepted that without specific treatment 70-80% of hips with clinically diagnosed osteonecrosis will progress to collapse. However, there are conflicting reports regarding the relationship between pain and outcome before femoral head collapse. Some surgeons are reluctant to operate on patients with asymptomatic or minimally symptomatic hips, assuming that these patients have a better prognosis than patients with pain. This study reviewed the outcome of 328 hips in 235 patients with nontraumatic osteonecrosis, all treated with core decompression and grafting. The preoperative stage, the extent of necrosis, and the Harris pain scores were correlated with the clinical and radiographic outcomes. Mean followup was 46 months. Patients with hips treated surgically did better as a group than patients with hips treated without surgery. A direct correlation was found between outcome and the stage and size of the necrotic lesion. Hips that had femoral head collapse were more painful than hips that did not have collapse and had a poorer outcome. Before collapse, outcome was correlated with the size of the necrotic lesion but there was no correlation with the preoperative pain level. These findings, although limited to patients with hips which had core decompression and grafting, support the observations of investigators who reported that most asymptomatic hips with osteonecrosis would progress without specific treatment. They also may apply to hips which have other forms of prophylactic treatment. Although several factors must be considered in determining the optimum treatment of hips with early stages of osteonecrosis, prophylactic treatment should not be withheld specifically because of the absence or paucity of pain.