The role of unicompartmental knee arthroplasty (UKA) in spontaneous osteonecrosis of the knee (SONK) remains controversial, even though SONK usually involves only medial compartment of the knee joint. We aimed to compare the survival rate and clinical outcomes of UKA in SONK and medial compartment osteoarthritis (MOA) via a meta-analysis of previous studies. MEDLINE database in PubMed, the Embase database, and the Cochrane Library were searched up to January 2018 with keywords related to SONK and UKA. Studies were selected with predetermined inclusion criteria: (1) medial UKA as the primary procedure, (2) reporting implant survival or clinical outcomes of osteonecrosis and osteoarthritis, and (3) follow-up period greater than 1 year. Quality assessment was performed using the risk of bias assessment tool for non-randomised studies (RoBANs). A random effects model was used to estimate the pooled relative risk (RR) and standardised mean difference. The incidence of UKA revision for any reason was significantly higher in SONK than in MOA group (pooled RR = 1.83, p = 0.009). However, the risk of revision due to aseptic loosening and all- cause re-operation was not significantly different between the groups. Moreover, when stratified by the study quality, high quality studies showed similar risk of overall revision in SONK and MOA (p = 0.71). Subgroup analysis revealed worse survival of SONK, mainly related to high failure after uncemented UKA. Clinical outcomes after UKA were similar between SONK and MOA (p = 0.66). Cemented UKA has similar survival and clinical outcomes in SONK and MOA. Prospective studies designed specifically to compare the UKA outcomes in SONK and MOA are necessary.
Occasionally, patients experience new or increased ankle pain following total knee arthroplasty (TKA). The aims of this study were to determine (1) how the correction of varus malalignment of the lower limb following TKA affected changes in alignment of the ankle and hindfoot, (2) the difference in changes in alignment of the ankle and hindfoot between patients with and without ankle osteoarthritis (OA), and (3) whether the rate of ankle pain and the clinical outcome following TKA differed between the 2 groups. We retrospectively reviewed prospectively collected data of 56 patients (99 knees) treated with TKA. Among these cases, concomitant ankle OA was found in 24 ankles. Radiographic parameters of lower-limb, ankle, and hindfoot alignment were measured preoperatively and 2 years postoperatively. In addition, ankle pain and clinical outcome 2 years after TKA were compared between patients with and without ankle OA.Background
Methods
Authors sought to determine the degree of lateral condylar hypoplasia of distal femur was related to degree of valgus malalignment of lower extremity in patients who underwent TKA. Authors also examined the relationships between degree of valgus malalignment and degree of femoral anteversion or tibial torsion. This retrospective study included 211 patients (422 lower extremities). Alignment of lower extremity was determined using mechanical tibiofemoral angle (mTFA) measured from standing full-limb AP radiography. mTFA was described positive value when it was valgus. Patients were divided into three groups by mTFA; more than 3 degrees of valgus (valgus group, n = 31), between 3 degrees of valgus to 3 degrees of varus (neutral group, n = 78), and more than 3 degrees of varus (varus group, n = 313). Condylar twisting angle (CTA) was used to measure degree of the lateral femoral condylar hypoplasia. CTA was defined as the angle between clinical transepicondylar axis (TEA) and posterior condylar axis (PCA). Femoral anteversion was measured by two methods. One was the angle formed between the line intersecting femoral neck and the PCA (pFeAV). The other was the angle formed between the line intersecting femoral neck and clinical TEA (tFeAV). Tibial torsion was defined as a degree of torsion of distal tibia relative to proximal tibia. It was determined by the angle formed between the line connecting posterior cortices of proximal tibial condyles and the line connecting the most prominent points of lateral and medial malleolus. Positive values represented relative external rotation. Negative values represented relative internal rotation.Background
Methods
Recently, concerns arose over the medial tibial bone resorption of a novel cobalt-chromium (CoCr) implant. This study aimed to investigate the effects of tibial component material, design, and patient factors on periprosthetic bone resorption and to determine its association with clinical outcomes after total knee arthroplasty (TKA). A total of 462 primary TKAs using five types of implants were included. To evaluate tibial periprosthetic bone resorption, we assessed radiolucent lines (RLL) and change in bone mineral density at the medial tibial condyle (BMDMT). Factors related to bone resorption were assessed using regression analysis. Clinical outcomes were also evaluated with respect to periprosthetic bone resorption. Compared to titanium (Ti) implants, CoCr implants showed a higher incidence of complete RLL (23.1% vs. 7.9% at two years post-TKA) and a greater degree of BMDMT reduction. However, there was no significant difference between the implants made of the same material. Increased medial tibial bone resorption was associated with male sex, osteoporosis, larger preoperative varus deformity, longer follow-up period, and lower body mass index. The periprosthetic bone resorption was not associated with clinical outcomes including changes in range of motion and WOMAC score. Furthermore, no cases warranted additional surgery. Periprosthetic bone resorption was associated with implant material but not with implant design. Moreover, patient factors were related to the medial tibial bone resorption post-TKA. However, the periprosthetic bone resorption was not associated with short-term clinical outcomes. We contend that researchers should incorporate integrative considerations when developing and assessing novel implants.
We sought to determine whether there was a difference in the posterior condylar offset (PCO), posterior condylar offset ratio (PCOR) following total knee arthroplasty (TKA) with anterior referencing (AR) or posterior referencing (PR) systems. We also assessed whether the PCO and PCOR changes, as well as patient factors were related to range of motion (ROM) in each referencing system. In addition, we examined whether the improvements in clinical outcomes differed between the two referencing systems. This retrospective study included 130 consecutive patients (184 knees) with osteoarthritis who underwent primary posterior cruciate ligament (PCL)-substituting fixed-bearing TKA. All patients were categorized into the AR or PR group according to the referencing system used. Radiographic parameters, including PCO and PCOR, were measured using true lateral radiographs. The difference between preoperative and postoperative PCO and PCOR values were calculated. Clinical outcomes including ROM and Western Ontario and McMaster University (WOMAC) scores were evaluated preoperatively and at 2 years after TKA. The PCO, PCOR values, and clinical outcomes were compared between the two groups. Furthermore, multiple linear regression analysis was performed to determine the factors related to postoperative ROM in each referencing system.Purpose
Methods
In a prospective multicentre study we investigated
variations in pain management used by knee arthroplasty surgeons
in order to compare the differences in pain levels among patients
undergoing total knee replacements (TKR), and to compare the effectiveness
of pain management protocols. The protocols, peri-operative levels
of pain and patient satisfaction were investigated in 424 patients
who underwent TKR in 14 hospitals. The protocols were highly variable
and peri-operative pain levels varied substantially, particularly
during the first two post-operative days. Differences in levels
of pain were greatest during the night after TKR, when visual analogue
scores ranged from 16.9 to 94.3 points. Of the methods of managing pain, the combined use of peri-articular
infiltration and nerve blocks provided better pain relief than other
methods during the first two post-operative days. Patients managed
with peri-articular injection plus nerve block, and epidural analgesia
were more likely to have higher satisfaction at two weeks after TKR.
This study highlights the need to establish a consistent pain management
strategy after TKR.
We aimed to document the pre-operative expectations in Korean patients undergoing total knee replacement using an established survey form and to determine whether expectations were influenced by sociodemographic factors or pre-operative functional status. Expectations regarding 17 items in the Knee Replacement Expectation Survey form were investigated in 454 patients scheduled for total knee replacement. The levels and distribution patterns of summated expectation and of five expectation categories (relief from pain, baseline activity, high flexion activity, social activity and psychological well-being) constructed from the 17 items were assessed. Univariate analyses and multivariate logistic regression were performed to examine the associations of expectations with the sociodemographic factors and the functional status. The top three expectations were relief from pain, restoration of walking ability, and psychological well-being. Of the five expectation categories, relief from pain was ranked the highest, followed by psychological well-being, restoration of baseline activity, ability to perform high flexion activities and ability to participate in social activities. An age of <
65 years, being employed, a high Western Ontario and McMaster Universities osteoarthritis index function score and a low Short-form 36 social score were found to be significantly associated with higher overall expectations.
Patient satisfaction is becoming increasingly important as a crucial outcome measure for total knee arthroplasty (TKA). We aimed to determine how well commonly-used clinical outcome scales correlate with patient satisfaction after TKA. In particular, we sought to determine whether patient satisfactions correlate better with absolute postoperative scores or preoperative to 12-month postoperative changes. Patient satisfaction was evaluated using four grades (enthusiastic, satisfied, noncommittal, and disappointed) for 438 replaced knees that were followed for longer than one year. Outcomes scales used AKS, WOMAC and SF-36 scores. Correlation analyses were performed to investigate the relation between patient satisfaction and the 2 different aspects of the outcome scales: postoperative scores evaluated at latest follow-ups and pre- to postoperative changes. The WOMAC function score was most strongly correlated with satisfaction (correlation Coefficient = 0.45). Absolute postoperative scores were better correlated with satisfaction than the pre- to postoperative changes for all scales. This study demonstrates that patient satisfaction correlates better with patient-derived and disease specific scales (WOMAC) than physician-driven (AKS) or generic (SF-36) measures. The present study also shows that absolute postoperative status is more important pre- to postoperative change when determining patient satisfaction.
Comprehensive anthropometric information is essential to avoid patella-related complications after TKA. We compared the anthropometric patellar dimensions of Korean and Western patients. In particular, we determined whether the reestablishment of original patellar thickness, residual bony thickness, and pre- to postoperative deviations between the median ridge position and the component center position influence the clinical and radiographic outcomes of TKAs. We measured anthropometric patellar dimensions in 752 osteoarthritic knees treated with TKA in 466 Korean patients and compared them with those of Western patients reported in the literature. We investigated the effects of postoperative overall thickness deviations, residual bony thickness after bone resection, and postoperative deviations of component center positions from median ridge positions versus clinical and radiographic outcomes evaluated 1 year after surgery. Korean patients undergoing TKA had thinner and smaller patellae than Western patients. We found no associations between pre- to postoperative overall thickness differences and clinical and radiographic outcomes and no differences between knees with a residual bony thickness of 12 mm or more and knees with a residual thickness of less than 12 mm, with the exception of WOMAC pain scores. We found no associations between postoperative deviations of component center position and clinical or radiographic outcomes. Our findings indicate bone resection for patellar resurfacing can be flexible without jeopardizing clinical outcome.
We examined the placement of the stem in relation to the medial tibial cortex when using total knee replacements (TKRs) with medially-offset tibial stems in Korean patients. Measurements were performed on the pre- and post-operative radiographs of 246 osteoarthritic knees replaced between January 2005 and May 2006 using the Genesis II or E-motion TKR with a medially-offset stem. Pre-operatively, we measured the distance between the mechanical axis and that of the tibial shaft and post-operatively, that between the midline of the tibial stem and the axis of the shaft. Knees were identified in which there was radiological contact between the tip of the stem and the medial tibial cortex. The mechanical axis was located medial to the axis of the shaft in 203 knees (82.5%). Post-operatively, the midline of the tibial stem was located medial to the tibial shaft axis in 196 knees (79.7%). In 16 knees (6.5%) there was radiological contact between the tibial stem or cement mantle and the medial tibial cortex. Our study has shown that the medially-offset stem in the tibial component may not be a good option for knees undergoing replacement for advanced osteoarthritis in some Korean patients.
We investigated the association between the radiological findings and the symptoms arising from the patellofemoral joint in advanced osteoarthritis (OA) of the knee. Four radiological features, joint space narrowing, osteophyte formation, translation of the patella and focal attrition were assessed in 151 consecutive osteoarthritic knees in 107 patients undergoing total knee replacement. The symptoms which were assessed included anterior knee pain which was scored, the ability to rise from a chair and climb stairs, and quadriceps weakness. Among the radiological features, only patellar translation and obliteration of the joint space had a statistically significant association with anterior knee pain (odds ratio (OR) 4.85; 95% confidence interval (CI) 1.83 to 12.88 and OR 11.23; 95% CI 2.44 to 51.62) respectively. Patellar translation had a statistically significant association with difficulty in rising from a chair (OR 9.06; 95% CI 1.75 to 45.11). Other radiological features, including osteophytes, joint space narrowing, and focal attrition had no significant association. Our study indicates that the radiological findings of patellar translation and significant loss of cartilage are predictive of patellofemoral symptoms and functional limitation in advanced OA of the knee.
This study aimed to determine the correlation between the amount of maximum flexion and the clinical outcome in 207 Koreans (333 knees) undergoing total knee replacement. The association of maximum flexion with clinical outcome was evaluated one year postoperatively using three scoring systems; the American Knee Society score, Western Ontario McMaster Universities Osteoarthritis index and the Short Form-36. The mean maximum flexion decreased post-operatively at 12 months from 140.1° (60° to 160°) to 133.0° (105° to 150°). Only the social function score of the Short Form-36 correlated significantly with maximum flexion (correlation coefficient = 0.180, p = 0.039). In comparative analyses of subgroups divided by a maximum flexion of 120°, we found no significant differences in any parameters except the social function score of the Short Form-36 (41.9
We sought to determine the degree of correlation between the condition of the patellar articular cartilage and patellofemoral symptoms and function in osteoarthritic patients undergoing total knee arthroplasty. The depth of the osteoarthritic lesion, as graded by the Outerbridge classification and its size and location were assessed to determine the condition of the patellar cartilage in 80 consecutive osteoarthritic knees undergoing total knee arthroplasty. The association between the condition of the cartilage and patellofemoral symptoms and function was investigated by correlation analysis. The depth and size of the lesion had a significant but weak correlation with anterior knee pain (r = −0.300 and −0.289; p = 0.007 and 0.009, respectively), whereas location had no significant association (p >
0.05). None had a significant association with patellofemoral functional parameters (chair-rising, stair-climbing, and quadriceps power) (p >
0.05). Our study indicates that patellofemoral symptoms and function are not completely determined by the condition of the cartilage. Caution should be taken when the symptoms and functional limitations are attributed to a lesion in the patellofemoral joint in making a decision regarding patellar resurfacing in total knee arthroplasty.