Glen Richardson

I can’t get no satisfaction after my total knee replacement: rhymes and reasons

Satisfaction is increasingly employed as an outcome measure for a successful total knee replacement (TKR). Satisfaction as an outcome measure encompasses many different intrinsic and extrinsic factors related to a persons experience before and after TKR. The Swedish Knee Arthroplasty Registry has previously demonstrated on a large population study that 17% of TKR recipients are not satisfied with their TKR outcome. This finding has been replicated in other countries. Similar significant factors emerged from these registry studies that are related to satisfaction. It would appear that satisfaction is better after more chronic diseases and whether the TKR results in pain relief or improved function. Importantly, unmet pre-operative expectations are a significant predictor for dissatisfaction following a TKR. It may be possible to improve rates by addressing the issues surrounding pain, function and expectation before embarking on surgery.

Continued stabilization of trabecular metal tibial monoblock total knee arthroplasty components at 5 years—measured with radiostereometric analysis

Background and purpose The trabecular metal tibial monoblock component (TM) is a relatively new option available for total knee arthroplasty. We have previously reported a large degree of early migration of the trabecular metal component in a subset of patients. These implants all appeared to stabilize at 2 years. We now present 5-year RSA results of the TM and compare them with those of the NexGen Option Stemmed cemented tibial component (Zimmer, Warsaw IN). Patients and methods 70 patients with osteoarthritis were randomized to receive either the TM implant or the cemented component. RSA examination was done postoperatively and at 6 months, 1 year, 2 years, and 5 years. RSA outcomes were translations, rotations, and maximum total point motion (MTPM) of the components. MTPM values were used to classify implants as “at risk” or “stable”. Results At the 5-year follow-up, 45 patients were available for analysis. There were 27 in the TM group and 18 in the cemented group. MTPM values were similar in the 2 groups (p = 0.9). The TM components had significantly greater subsidence than the cemented components (p = 0.001). The proportion of “at risk” components at 5 years was 2 of 18 in the cemented group and 0 of 27 in the TM group (p = 0.2). Interpretation In the previous 2-year report, we expressed our uncertainty concerning the long-term stability of the TM implant due to the high initial migration seen in some cases. Here, we report stability of this implant up to 5 years in all cases. The implant appears to achieve solid fixation despite high levels of migration initially.

The role of perceived injustice in the prediction of pain and function after total knee arthroplasty.

&NA; Perceived injustice prospectively predicted more severe postsurgical pain after total knee arthroplasty, even when controlling for other pain‐related psychological variables. &NA; Emerging evidence suggests that the appraisal of pain and disability in terms of justice‐related themes contributes to adverse pain outcomes. To date, however, research on the relation between perceived injustice and pain outcomes has focused primarily on individuals with musculoskeletal injuries. The primary aim of this study was to investigate the role of perceived injustice in the prediction of pain and disability after total knee arthroplasty (TKA). The study sample consisted of 116 individuals (71 women, 45 men) with osteoarthritis of the knee scheduled for TKA. Participants completed measures of pain severity, physical disability, perceptions of injustice, pain catastrophizing, and fear of movement before surgery, and measures of pain and disability 1 year after surgery. Prospective multivariate analyses revealed that perceived injustice contributed modest but significant unique variance to the prediction of postsurgical pain severity, beyond the variance accounted for by demographic variables, comorbid health conditions, presurgical pain severity, pain catastrophizing, and fear of movement. Pain catastrophizing contributed significant unique variance to the prediction of postsurgical disability. The current findings add to a growing body of evidence supporting the prognostic value of perceived injustice in the prediction of adverse pain outcomes. The results suggest that psychosocial interventions designed to target perceptions of injustice and pain catastrophizing before surgery might contribute to more positive recovery trajectories after TKA.

Metal-on-metal hip surface replacement

Metal-on-metal resurfacing of the hip (MoMHR) has enjoyed a resurgence in the last decade, but is now again in question as a routine option for osteoarthritis of the hip. Proponents of hip resurfacing suggest that its survival is superior to that of conventional hip replacement (THR), and that hip resurfacing is less invasive, is easier to revise than THR, and provides superior functional outcomes. Our argument serves to illustrate that none of these proposed advantages have been realised and new and unanticipated serious complications, such as pseudotumors, have been associated with the procedure. As such, we feel that the routine use of MoMHR is not justified.

Validation of the Injustice Experiences Questionnaire Adapted for Use withPatients with Severe Osteoarthritis of the Knee

Objective: Recent research has linked perceptions of injustice to problematic recovery outcomes for individuals with musculoskeletal injuries. However, the measure currently used to assess perceived injustice is not readily applicable to individuals who have a pain condition, such as osteoarthritis (OA), where pain onset is insidious as opposed to traumatic. The purpose of this study was to validate a modified version of the Injustice Experiences Questionnaire (IEQ-chr) for patients with OA of the knee. Methods: The IEQ-chr was administered along with measures of pain catastrophizing, fear of movement, depressive symptoms, pain severity and physical function to 110 individuals with severe OA of the knee. Results: Principal component analyses yielded a factor structure similar to that in the original validation study. The IEQ-chr had high internal consistency (Chronbach alpha=0.88), and was significantly correlated with pain catastrophizing, fear of movement, depressive symptoms, pain severity and physical function. Regression analyses revealed that the IEQ-chr contributed significant unique variance to prediction of pain severity and physical function, beyond the variance accounted for by measures of pain catastrophizing and fear of movement. Conclusions: The findings of the present study support the construct validity of the IEQ-chr in the context of osteoarthritis, and suggest that this measure may be useful in psychosocial assessment of individuals at risk for adverse pain outcomes. The discussion addresses theoretical and clinical implications of these findings.

Intraoperative passive knee kinematics during total knee arthroplasty surgery

Surgical navigation systems for total knee arthroplasty (TKA) surgery are capable of capturing passive three‐dimensional (3D) angular joint movement patterns intraoperatively. Improved understanding of patient‐specific knee kinematic changes between pre and post‐implant states and their relationship with post‐operative function may be important in optimizing TKA outcomes. However, a comprehensive characterization of the variability among patients has yet to be investigated. The objective of this study was to characterize the variability within frontal plane joint movement patterns intraoperatively during a passive knee flexion exercise. Three hundred and forty patients with severe knee osteoarthritis (OA) received a primary TKA using a navigation system. Passive kinematics were captured prior to (pre‐implant), and after prosthesis insertion (post‐implant). Principal component analysis (PCA) was used to capture characteristic patterns of knee angle kinematics among patients, to identify potential patient subgroups based on these patterns, and to examine the subgroup‐specific changes in these patterns between pre‐ and post‐implant states. The first four extracted patterns explained 99.9% of the diversity within the frontal plane angle patterns among the patients. Post‐implant, the magnitude of the frontal plane angle shifted toward a neutral mechanical axis in all phenotypes, yet subtle pattern (shape of curvature) features of the pre‐implant state persisted.

The Knee Adduction Moment During Gait is Associated With the Adduction Angle Measured During Computer-Assisted Total Knee Arthroplasty

Computer-assisted surgery can be used to measure 3-dimensional knee function during arthroplasty surgery; however, it is unknown if the movement of the knee measured during surgery is related to the in vitro, dynamic state of the knee joint, specifically the knee adduction moment during gait, which has been related to implant migration. The purpose of this study was to determine if the preoperative adduction moment is correlated with the knee abduction/adduction angle measured intraoperatively. A statistically significant correlation was found between the mean (r(2) = 0.59; P = .001) and peak (r(2) = 0.53; P = .003) preoperative knee adduction moment and the mean abduction/adduction angle measured intraoperatively. The association found in this study suggests the potential for incorporating functional information that relates to surgical outcome into surgical decision making using computer-assisted surgery.

Minimizing infection risk: fortune favors the prepared mind.

Despite advances in care, infection in total joint arthroplasty remains a serious problem that has yet to be solved. Reported infection rates range from <0.5% in highly specialized centers to a high of 2% as reported at a national level. The epidemiology of total joint arthroplasty remains challenging because of the relatively low, but significant, incidence of infection. Still, there are variables that can be addressed that have demonstrated evidence regarding reduction in infection rates. These variables include optimizing medical conditions in the preoperative period such as anemia, blood glucose, and nutrition. In the perioperative period, administration of parenteral antibiotics within 1 hour of incision is a must. The effect of the operating room environment is less clear, but it is evident that traffic flow in the operating room has a negative effect on infection rates. Skin preparation with chlohexidine is now the agent of choice, and evidence exists that iodophor impregnated occlusive dressings add value. Razors should not be used. Surgical staples for closure have an increased risk of superficial infection as compared to subcuticular sutures. In the postoperative period, early, persistent wound drainage should be managed aggressively. There is no evidence to support the use of parenteral antibiotics past 24 hours in routine cases. Patients should be advised about prophylaxis for infection when undergoing dental work and other high-risk procedures. There is a strong movement to extend this prophylactic period indefinitely, as opposed to 2 years postoperatively. Finally, and perhaps most importantly, it is the surgeons responsibility to be aware of all these issues and to strongly advocate for patient safety in ensuring that infection risk is minimized.

Knee Kinematics Feature Selection for Surgical and Nonsurgical Arthroplasty Candidate Characterization

Keywords: Knee Kinematic, Biomechanical Data, Feature Selection, Complexity Measures, Arthroplasty. Abstract: The purpose of this study is to investigate a method to select a set of knee kinematic data fatures to characterize surgical vs nonsurgical arthroplasty subjects. The kinematic features are generated from 3D knee kinematic data patterns, namely, rotations of flexion-extension, abduction-adduction, and tibial internal-external recorded during a walking task on a dedicated treadmill. The discrimination features are selected using three types of statistical complexity measures: the Fisher discriminant ratio, volume of overlap region, and feature efficiency. The interclass distance measurements which the features thus selected induce demonstrate their effectiveness to characterize surgical and nonsurgical subjects for arthroplasty.

Higher periprosthetic fracture rate associated with use of modern uncemented stems compared to cemented stems in femoral neck fractures

Introduction: Hemiarthroplasty is the preferred treatment for displaced femoral neck fractures in elderly patients. Recently, short tapered-wedge cementless stems have increasingly been used in this population. However, historic data has consistently shown higher rates of periprosthetic fracture with uncemented stems in hip fracture patients. This study aims to evaluate the rate of periprosthetic fracture requiring re-operation and all-cause mortality between cemented and uncemented femoral stem designs including more recent short tapered-wedge cementless stems in hip fracture patients. Methods: A retrospective chart and radiographic review of patients received bipolar hemiarthroplasty for femoral neck fractures from 2010–2016. Patients biologically (age ≥ 65 years) or physiologically (American Society of Anesthesiologists (ASA) class ≥ 3) elderly were eligible. The uncemented group was subdivided into tapered-wedge stems (a broach only system) and reamed uncemented stems. The primary outcome was periprosthetic fracture requiring re-operation. Results: We included 657 patients in total, with 296 and 361 patients in the uncemented and cemented stem groups respectively. In the uncemented group there were 197 tapered-wedge and 99 reamed uncemented stems. There was a significantly higher rate of periprosthetic fracture requiring re-operation in the uncemented group (3.0% vs. 0.6%) (p ≤ 0.05). There were no significant differences in rates of all-cause mortality, infection or all-cause re-operation. Conclusions: Compared to modern uncemented femoral stem designs, cemented stems yield lower rates of periprosthetic fracture requiring re-operation, without increasing risk of all-cause mortality. Tapered-wedge stems had similar rates of re-operation due to periprosthetic fracture as reamed uncemented stems.