Assuring the happy total knee replacement patient

Navigated functional alignment total knee arthroplasty achieves reliable, reproducible and accurate results with high patient satisfaction

PURPOSE

The decision on which technique to perform a total knee arthroplasty (TKA) has become more complicated over the last decade. Perceived limitations of mechanical alignment (MA) and kinematic alignment (KA) have led to the development of the functional alignment (FA) philosophy. This study aims to report the 2-year results of an initial patient cohort in terms of revision rate, PROMs and complications for Computer Aided Surgery (CAS) Navigated FA TKA.

METHODS

This paper reports a single surgeon's outcomes of 165 consecutive CAS FA TKAs. The final follow-up was 24 months. Pre-operative and post-operative patient-reported outcome measures, WOMAC and KSS, and intra-operative CAS data, including alignment, kinematic curves, and gaps, are reported. Stress kinematic curves were analysed for correlation with CAS final alignment and CAS final alignment with radiographic long-leg alignment. Pre- and post-operative CPAK and knee phenotypes were recorded. Three different types of prostheses from two manufacturers were used, and outcomes were compared. Soft tissue releases, revision and complication data are also reported.

RESULTS

Mean pre-operative WOMAC was 48.8 and 1.2 at the time of the final follow-up. KSS was 48.8 and 93.7, respectively. Pre- and post-operative range of motion was 118.6° and 120.1°, respectively. Pre-operative and final kinematic curve prediction had an accuracy of 91.8%. CAS data pre-operative stress alignment and final alignment strongly correlate in extension and flexion, r = 0.926 and 0.856, p < 0.001. No statistical outcome difference was detected between the types of prostheses. 14.5% of patients required soft tissue release, with the lateral release (50%) and posterior capsule (29%) being the most common.

CONCLUSION

CAS FA TKA in this cohort proved to be a predictable, reliable, and reproducible technique with acceptable short-term revision rates and high PROMs. FA can account for extremes in individual patient bony morphology and achieve desired gap and kinematic targets with soft tissue releases required in only 14.5% of patients.

LEVEL OF EVIDENCE

IV (retrospective case series review).

Comparison of Femoral Component Rotation between Robotic-Assisted vs. Soft-Tissue Tensor Total Knee Arthroplasty with Anatomic Implants

Background and Objectives: Total knee arthroplasty (TKA) is the most effective treatment method for end-stage osteoarthritis. One of the most important aspects of this surgery is adequate implant positioning, as it guarantees the desired outcome of restoring limb biomechanics. Surgical technique is being continuously improved along with hardware development. There are two novel devices designed to help establish proper femoral component rotation: soft-tissue tensor and robotic-assisted TKA (RATKA). This study compared the femoral component rotation achieved with the use of three methods: RATKA, soft tissue tensioner and the conventional measured-resection technique, all of them utilizing anatomical design prosthesis components. Materials and Methods: A total of 139 patients diagnosed with end-stage osteoarthritis underwent total knee arthroplasty between December 2020 and June 2021. After the surgery, they were divided into three groups depending on procedure technique and implant type: Persona (Zimmer Biomet) + Fuzion Balancer, RATKA + Journey II BCS or conventional TKA + Persona/Journey. Postoperatively, a computed tomography examination was performed in order to measure femoral component rotation. All three groups were compared independently during statistical analysis. Fisher's exact, Kruskal-Wallis and Dwass-Steel-Crichtlow-Fligner tests were used for particular calculations. Results: Statistically significant differences in femoral component rotation between groups were noticed. However, in terms of values other than 0° in external rotation, no significant variance was revealed. Conclusions: Additional total knee arthroplasty instruments seem to improve the outcomes of the surgery, providing better component positioning than in the conventional measured-resection technique based only on bone landmarks.

Using a patella reduced technique while balancing a TKA results in restored physiological strain in the collateral ligaments: an ex vivo kinematic analysis

INTRODUCTION

Poor soft tissue balance in total knee arthroplasty (TKA) often results in patient dissatisfaction and reduced joint longevity. Patella-in-place balancing (PIPB) is a novel technique which aims to restore native collateral ligament behavior without collateral ligament release, while restoring post-operative patellar position. This study aimed to assess the effectiveness of this novel technique through a detailed ex vivo biomechanical analysis by comparing post-TKA tibiofemoral kinematics and collateral ligament behavior to the native condition.

MATERIALS AND METHODS

Eight fresh-frozen cadaveric legs (89.2 ± 6 years) were tested on a validated dynamic knee simulator, following computed tomography imaging. Specimens were subjected to passive flexion (10-120°), squatting (35-100°), and varus/valgus laxity testing (10 Nm at 0°, 30°, 60°, 90° flexion). An optical motion capture system recorded markers affixed rigidly to the femur, tibia, and patella, while digital extensometers longitudinally affixed to the superficial medial collateral ligament (MCL) and lateral collateral ligament (LCL) collected synchronized strain data. Following native testing, a Stryker Triathlon CR TKA (Stryker, MI, USA) was performed on each specimen and the identical testing protocol was repeated. Statistical analyses were performed using a linear mixed model for functional motor tasks, while Wilcoxon signed-rank test was used for laxity tests (p < 0.05).

RESULTS

Postoperative laxity was lower than the native condition at all flexion angles while post-operative ligament strain was lowered only for MCL at 30° (p = 0.017) and 60° (p = 0.011). Postoperative femoral rollback patterns were comparable to the native condition in passive flexion but demonstrated a more pronounced medial pivot during squatting.

CONCLUSIONS

Balancing a TKA with the PIPB technique resulted in reduced joint laxity, while restoring collateral ligament strains. The technique also seemed to restore kinematics and strains, especially in passive flexion.

The Effect of Posterior Cruciate Ligament Release on Kinematics and Outcomes in Primary Total Knee Arthroplasty With a Dual-Pivot Conforming Polyethylene

BACKGROUND

Ultracongruent bearings are increasingly utilized in total knee arthroplasty (TKA); however, implications of surgical technique on knee kinematics and outcomes with these bearings are not well understood. This study's purpose was to evaluate the relationship of 3-dimensional knee kinematics and patient-reported outcome measures (PROMs) in a dual-pivot congruent bearing TKA with and without posterior cruciate ligament (PCL) release.

METHODS

Forty patients undergoing TKA with an asymmetric ultracongruent bearing were prospectively enrolled for gait analysis preoperatively and 4 months postoperatively. Three-dimensional gait analysis was performed utilizing infrared motion capture. Knee kinematic data and PCL disposition were analyzed for correlations with PROMs.

RESULTS

The PCL was fully released in 52.5% (21/40) of cases. Greater maximum anteroposterior femoral translation correlated with lower Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (rho = -0.596, P = .012), greater Knee Society Score pain with level walking (rho = 0.411, P = .101), and greater Knee Society Score pain while climbing stairs (rho = 0.469, P = .058) at 4-month follow-up. The PCL-release group was associated with greater maximum femoral anteroposterior translation (9.8 vs 5.5 mm, P = .053) and greater maximum internal tibial rotation (-6.2° vs -3.0°, P = .040), supporting a more anterior-based position of the medial condyle. The PCL released group had lower median Knee Injury and Osteoarthritis Outcome Score for Joint Replacement scores (70.7 vs 76.3, P = .031) and reported that their knees "sometimes or always" feel normal less frequently (81.8% vs 92.3%, P = .576).

CONCLUSION

With this asymmetric ultracongruent bearing TKA, preservation or partial titration release of the PCL, as opposed to full PCL release, appears to minimize deleterious anterior femoral translation and internal tibial rotation, which is correlated with optimized patient-reported outcomes.

LEVEL OF EVIDENCE

II.

Can digital engagement improve outcomes for total joint replacements?

Background

Patient activation and engagement can improve outcomes of medical and surgical care by increasing involvement of patients in their care plan. We designed a digital engagement tool to improve surgical cancellation and post-surgical outcomes for adult patients undergoing total joint replacements by providing patient education materials via email or text, in small increments throughout the perioperative period.

Methods

We assessed the tool's impact using a quasi-experimental design comparing patients scheduled for surgery January–June 2017 (pre-intervention) versus January–June 2018 (post-intervention). Post-intervention patients with digital contact information in the medical record were automatically enrolled. We extracted de-identified administrative data for all patients during both time periods and utilized an intent-to-treat approach including all post-intervention patients regardless of enrollment. Surgical cancellation and post-surgical outcomes (length of stay, discharge to home and revisits and readmissions) were compared between periods using adjusted regression models. We also examined associations between measures of engagement with the intervention and outcomes.

Results

A total of 2027 joint replacement patients were included (720 hip replacements; 1307 knee replacements). Adjusting for gender, age and insurance type, both hip and knee patients in the post-intervention group were more likely to have a cancelled surgery, but cancellations were less likely to be on the day of surgery compared to pre-intervention patients. Post-intervention patients were also less likely to have length of stay >2 days. Forty- three per cent of hip and 47% of knee patients in the post-period received the intervention and most were highly engaged. Higher engagement was associated with lower odds of surgical cancellation, shorter stays and higher odds of discharge home.

Conclusion

Findings suggest that utilization of a digital patient engagement tool translates into improved hospital efficiency and patient outcomes, particularly for those highly engaged.

Tibial baseplate position and posterior cruciate ligament status impact patient-reported outcomes in conforming dual-pivot bearing total knee arthroplasty

Background

In an effort to optimize clinical outcomes and enhance stability, ultracongruent bearings have been increasingly used in primary total knee arthroplasty (TKA). The importance of the posterior cruciate ligament (PCL) and optimal sagittal tibial baseplate position in ultracongruent bearing TKA remains unknown. This study sought to determine whether these modifiable, surgical-technique-dependent variables meaningfully impact patient-reported outcome measures.

Methods

A total of 759 primary TKAs of the same dual-pivot design performed using a consistent surgical technique between January 2016 and April 2019 were retrospectively reviewed. PCL status was recorded, and anteroposterior (AP) tibial baseplate position and posterior tibial slope were measured by two independent blinded raters. Patient-reported outcomes related to pain, function, satisfaction, and activity level were analyzed in relationship to PCL status, posterior tibial slope, and AP tibial baseplate position, in addition to other pertinent covariates.

Results

Median age and body mass index of the cohort were 68.3 years and 33.4 kg/m², respectively, with 73% being female. In multivariate analysis, partial or full release of the PCL was predictive of a knee “always” feeling normal (odds ratio 1.42, P = .041). Furthermore, tibial baseplate position closer to the middle of the tibia was associated with greater improvements in pain with level walking, pain while climbing stairs, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement total scores (P ≤ .079).

Conclusion

In congruent dual-pivot bearing TKA, partially or fully releasing the PCL and AP tibial baseplate position closer to the middle of the tibia may provide greater improvement in pain and function scores at minimum 1-year follow-up.

Evaluating the "Patella-Friendly" Concept in Total Knee Arthroplasty: A Minimum 15-Year Follow-Up Outcome Study Comparing Constant Radius, Multiradius Cruciate-Retaining, and Nonanatomical Cruciate-Retaining Implants

BACKGROUND

Patella-friendly femoral components were developed in order to reduce anterior knee pain and patellofemoral complications in total knee arthroplasty (TKA), but their effect on long-term outcome is still unclear.

METHODS

We retrospectively evaluated prospectively collected data from 3 groups consisting of 100 patients (100 knees in each). In group A, the constant radius a-MP, in group B the multiradius cruciate-retaining Genesis II, and in group C the nonanatomic, multiradius, cruciate-retaining AGC TKA was implanted. Patients of all groups were matched for age, gender, side, body mass index, and length of follow-up. Preoperative and postoperative clinical outcome data in the form of Knee Society System (KSS), Short Form-12, Western Ontario and McMaster University Osteoarthritis Index, and Oxford Knee Score were available at regular intervals for groups A and B. For patients of group C, KSS score data were available at the same time intervals. In all groups, the patellofemoral compartment was assessed using the Clinical Patella Score scale. Anterior knee pain, secondary patella resurfacing, implant failure, and radiological outcome were assessed in patients of all groups.

RESULTS

At 10-year and 15-year follow-up, patients of group A showed statistically significant (s.s.) higher (all P = .000) KSS values as compared to those of groups B and C. At 15-year follow-up, patients of group B showed s.s. higher (P = .001) KSS values as compared to those of group C. At 10-year and 15-year follow up, patients of group A showed s.s. higher (all P = .00) Western Ontario and McMaster University Osteoarthritis Index and Oxford Knee Score values as compared to those of group B. At 15-year follow-up only, patients of group A showed s.s. higher (P = .00) Short Form-12 (physical) values as compared to those of group B. In terms of Clinical Patella Score, patients in group A had s.s. higher values (P = .05) when compared to those of groups B and C. Anterior knee pain was recorded in 4.4% of TKAs in group A, 7.5% in group B, and 17.2% in group C. One (1.1%) patient in group A, 3 (3.25%) in group B, and 7 (8%) in group C underwent secondary resurfacing.

CONCLUSION

Anatomical, patella-friendly, constant radius femoral components outperform others in reducing anterior knee pain and patella complications in TKA in which the patellae are left nonresurfaced.

Distal femoral valgus cut angle in degenerative varus knees of an Arabic population

PURPOSE

This study aimed to determine the natural distribution of the distal femoral valgus cut angle (VCA) among an Arabic population; the percentage of patients whose VCA fell within the range of 5-6°; and whether demographic variables, severity of the pre-operative varus, and morphological femoral parameters would correlate with the VCA. To our knowledge, VCA measurement of degenerative varus knees among an Arabic population has not been reported previously in the literature.

METHODS

A total of 492 knees (246 patients) were included. The VCA was measured on pre-operative hip-to-ankle radiographs according to a standard protocol. Patient characteristics and radiographic parameters were recorded.

RESULTS

The mean VCA was 6.03 ± 1.69°, with 230 knees (46.7%) falling within the (5-6°) range. The VCA significantly differed according to the patient's age (p = 0.02), sex (p = 0.009), height (p = 0.03), degree of varus (p < 0.001), hip offset (p = 0.013), and the presence of excessive lateral coronal bowing of the femur (p = 0.01). Among these, the degree of varus was the only significant factor on the multivariable regression analysis (p = 0.005).

CONCLUSION

The mean VCA in our population was 6.03°; however, the wide distribution of the VCA in our patients does not support the use of a fixed value. The severity of the pre-operative varus seems to be an independent factor with a positive correlation to the VCA and may also provide a clue to the ideal VCA if measurement of this angle is not available.

Balance and quality of life after total knee arthroplasty

OBJECTIVE

To evaluate the change in balance and quality of life in patients undergoing total knee arthroplasty for primary gonarthrosis.

METHOD

Patients aged 60 years or older were evaluated in relation to the balance and quality of life before total knee arthroplasty and six months after surgery. To assess balance, this study used the Motor Scale Test for the Elderly; quality of life was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire and the Short Form Health Survey. A control group consisting of healthy adults, age- and gender-paired, was used to compare the balance after surgery results.

RESULTS

Twenty-eight patients completed the study, of a total of 37 arthroplasties. The mean age was 70.18 ± 6.17 years. All variables were statistically significant (p ≤ 0.05) for improved balance and quality of life after arthroplasty. It was observed that, after knee arthroplasty, the level of balance does not reach that expected for healthy individuals (p ≤ 0.05).

CONCLUSION

Total knee arthroplasty is effective at improving balance six months after surgery, as well as all domains of quality of life. However, it is not able to restore balance to a level comparable to that of healthy individuals.

Development and validation of a shared decision-making instrument for health-related quality of life one year after total hip replacement based on quality registries data

RATIONALE, AIMS AND OBJECTIVES

Clinicians considering improvements in health-related quality of life (HRQoL) after total hip replacement (THR) must account for multiple pieces of information. Evidence-based decisions are important to best assess the effect of THR on HRQoL. This work aims at constructing a shared decision-making tool that helps clinicians assessing the future benefits of THR by offering predictions of 1-year postoperative HRQoL of THR patients.

METHODS

We used data from the Swedish Hip Arthroplasty Register. Data from 2008 were used as training set and data from 2009 to 2012 as validation set. We adopted two approaches. First, we assumed a continuous distribution for the EQ-5D index and modelled the postoperative EQ-5D index with regression models. Second, we modelled the five dimensions of the EQ-5D and weighted together the predictions using the UK Time Trade-Off value set. As predictors, we used preoperative EQ-5D dimensions and the EQ-5D index, EQ visual analogue scale, visual analogue scale pain, Charnley classification, age, gender, body mass index, American Society of Anesthesiologists, surgical approach and prosthesis type. Additionally, the tested algorithms were combined in a single predictive tool by stacking.

RESULTS

Best predictive power was obtained by the multivariate adaptive regression splines (R²  = 0.158). However, this was not significantly better than the predictive power of linear regressions (R²  = 0.157). The stacked model had a predictive power of 17%.

CONCLUSIONS

Successful implementation of a shared decision-making tool that can aid clinicians and patients in understanding expected improvement in HRQoL following THR would require higher predictive power than we achieved. For a shared decision-making tool to succeed, further variables, such as socioeconomics, need to be considered.

Do Medial Pivot Kinematics Correlate With Patient-Reported Outcomes After Total Knee Arthroplasty?

BACKGROUND

Many total knee arthroplasty (TKA) implants are designed to facilitate a medial pivot kinematic pattern. The purpose of this study was to determine whether intraoperative medial pivot kinematic patterns are associated with improved patient outcomes.

METHODS

A retrospective review of consecutive primary TKAs was performed. Sensor-embedded tibial trials determined kinematic patterns intraoperatively. The center of rotation (COR) was identified from 0° to 90° and from 0° to terminal flexion, and designated medial-pivot or non-medial pivot based on accepted criteria. Patient-reported outcomes were measured preoperatively and at minimum one-year follow-up.

RESULTS

The analysis cohort consisted of 141 TKAs. Mean age and median BMI were 63.7 years and 33.8 kg/m², respectively. Forty-percent of TKAs demonstrated a medial pivot kinematic pattern intraoperatively. A medial pivot pattern was more common with posterior cruciate-retaining (CR) and posterior cruciate-substituting/anterior lipped (CS) implants when compared to posterior stabilized (PS) TKAs (P ≤.0150). Regardless of bearing type, minimum one-year Knee Society scores and UCLA activity level did not significantly differ based on medial vs non-medial pivot patterns (P ≥.292). For patients with posterior cruciate-sacrificing implants, there were trends for greater median improvement in Knee Society objective (46 vs 31.5 points, P =.057) and satisfaction (23 vs 14 points, P =.067) scores in medial pivot knees.

CONCLUSION

A medial pivot pattern may not significantly govern clinical success after TKA based on intraoperative kinematics and modern outcome measures. Further research is warranted to determine if a particular kinematic pattern promotes optimal clinical outcomes.

The medial border of the tibial tuberosity as an auxiliary tool for tibial component rotational alignment during total knee arthroplasty (TKA)

PURPOSE

The objective of this study was to quantify the amount of ensuing internal rotation of the tibial component when positioned along the medial border of the tibial tubercle, thus establishing a reproducible intraoperative reference for tibial component rotational alignment during total knee arthroplasty (TKA).

METHODS

The angle formed from the tibial geometric centre to the intersection of both lines from the middle of the tibial tuberosity and its medial border was measured in 50 patients. The geometric centre was determined on an axial CT slice at 10 mm below the lateral tibial plateau and transposed to a slice at the level of the most prominent part of the tibial tuberosity. Similar measurements were taken in 25 patients after TKA, in order to simulate the intraoperative appearance of the tibia after making its proximal resection.

RESULTS

This angle was found to be similar (n.s.) in normal and post-TKA tibiae [median 20.4° (range 15°-24°) vs. 20.7° (range 16°-25°), respectively]. In 89.3 % of the patients, the angle ranged from 17° to 24°. No statistical difference (p n.s.) was found between women and men in both normal [median -20.7° (range 16°-25°) vs. 19.9° (range 15°-24°)] and post-TKA tibiae [median 21.4° (range 19°-24°) vs. 20° (range 16°-25°)].

CONCLUSION

This study found that in 90 % of the patients, the medial border of the tibial tuberosity is internally rotated 17°-24° in relation to the line connecting the middle of the tuberosity to the tibial geometric centre. Since this anatomical landmark may be more easily identifiable intraoperatively than the commonly used "medial 1/3", it can provide a better quantitative reference point and help surgeons achieve a more accurate tibial implant rotational position.

LEVEL OF EVIDENCE

Cohort and case control studies, Level III.

Patient's Height and Hip Medial Offset Are the Main Determinants of the Valgus Cut Angle During Total Knee Arthroplasty

BACKGROUND

Valgus cut angle (VCA), defined as the angle between the anatomical and the mechanical axes of femur, is an important parameter upon which a critical step of knee arthroplasty is based. Some variables have been proposed to affect the magnitude of this cut. However, little information is available regarding whether a generic value can be used, or if a patient-specific value from a long leg X-ray, or factors that can be determined preoperatively, is necessary to accurately set the VCA.

METHODS

Standard standing 3-joint views were used to measure a number of anatomical measurements in 358 limbs, 202 patients (116 women, 86 men). Neck-shaft angle, medial offset, femoral length (FL), distal femoral articular angle, and VCA were measured. Demographic data including gender and height were extracted from hospital charts. The correlation of VCA with each of the other factors was evaluated using linear regression and t-test and finally multivariate analysis.

RESULTS

The average VCA was 5.76° (range 4-8). Gender and distal femoral articular angle were not related to VCA (P = .343 and .995). FL was found to be a function of height with similar effects on multivariate analysis. Only the height (or FL) and femoral offset were identified as independent factors, with a negative correlation for the former (P < .001) and a positive correlation for the latter (P < .001).

CONCLUSION

Femoral offset and height are the 2 independent factors determining VCA. Other parameters are indirectly related to these 2 factors. Tall patients with a small femoral offset have smaller VCA and short patients with a large offset have larger VCA. The wide variety of VCA values does not support using a generic value for all patients during knee arthroplasty.

Affective temperament does not influence satisfaction after total knee arthroplasty

BACKGROUND

Inherent temperament of the patient may predict the outcome of the surgical procedure. The purpose of this study was to ascertain whether negative affective temperament affects patient satisfaction and outcome measures.

METHODS

This prospective study included 143 patients who underwent total knee arthroplasty for primary arthrosis. Preoperatively, the Memphis, Pisa, Paris and San Diego-Auto questionnaire was used to define the temperament of the patient. Knee Society Score (KSS) and short form-36 (SF-36) outcome measures were used to evaluate the functional outcome.

RESULTS

No relationship was determined between temperament and satisfaction (P = .734). Overall, the satisfaction rate of the procedure in our patients was 93%. The KSS improved from a mean of 47.9 to 70.1 (F = 124.275; P < .05) and the SF-36 physical component summary, and SF-36 mental component summary scores improved to a mean of 39.5 and 43.04 points, respectively.

CONCLUSION

Temperament was not found to have any effect on patient satisfaction. However, patient satisfaction was directly related to better functional outcomes.

Changes in physical activity following total hip or knee arthroplasty: a matched case-control study from the EPIC-Norfolk cohort

Objective:

To assess self-reported physical activity changes pre- compared to post-operatively in patients undergoing total hip or knee arthroplasty, and to compare this to an age- and gender-matched cohort of people who have not undergone arthroplasty.

Design:

Population-based prospective cohort study.

Setting:

Norfolk, United Kingdom.

Subjects:

People who had undergone hip or knee arthroplasty, compared to an age- and gender-matched non-arthroplasty cohort.

Intervention:

Primary total hip or knee arthroplasty.

Main measures:

Physical activity, measured using the EPIC Physical Activity Questionnaire (EPAQ2).

Results:

A total of 400 people from the EPIC-Norfolk community cohort were identified who had undergone hip or knee arthroplasty. In all, 767 people were identified to form an age- and gender-matched non-arthroplasty cohort. Mean post-operative follow-up was 43 months post-total hip and 41 months post-total knee arthroplasty. There was a statistically significant reduction from pre- to post-arthroplasty in the number of flights of stairs climbed weekly (hip: mean difference (MD): 6.8; P < 0.01; knee: MD: 10.2; P < 0.01), duration of walking (hip: MD: 1.4 hours/week; P = .02; knee: MD: 2.2 hours/week; P < 0.01) and duration of total recreational activity (hip: MD: 1.1 hours/week; P = 0.02). Compared to the non-arthroplasty cohort, duration of physical activity was lower post-total hip arthroplasty (MD: 1.8 hours/week; P = 0.01). The number of flights of stairs climbed weekly (MD: 12.0; P < 0.01), total recreational activity (MD: 1.7 hours/week; P = 0.04) and physical activity energy expenditure (MD: 5.7 Mets-hours/week; P = 0.05) were lower for people post-total knee arthroplasty compared to the matched controls.

Conclusions:

Physical activity did not increase, and in some instances decreased, following total hip or knee arthroplasty.

Psychiatric disease as a risk factor in fast-track hip and knee replacement

Recent studies suggest that patients with psychiatric disorders tend to do worse than patients without a psychiatric diagnosis when undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA). Whether this is due to their psychiatric condition, pharmacological treatment, a combination of the two, or something else has not been thoroughly analyzed-and there are no internationally accepted guidelines for perioperative management of psychiatric patients. This overview summarizes our current knowledge on perioperative risks in patients with preoperative psychiatric disorders and the possible role of psychotropic drugs in the perioperative course. This will be useful when planning future strategies for improvement of surgical outcome following hip and knee arthroplasty.

Postoperative Pain After Primary Total Knee Arthroplasty: Comparison of Local Injection Analgesic Cocktails and the Role of Demographic and Surgical Factors

BACKGROUND

It has been reported that pain-related outcomes after total knee arthroplasty (TKA) may vary with different analgesic techniques and with patient demographics. The purposes of this study were to compare local infiltration of regular bupivacaine (periarticular infiltration [PAI] group) vs liposomal bupivacaine (LBUP group) and to examine the effect of patient characteristics on postoperative pain after TKA.

METHODS

The study sample included 665 consecutive TKA cases performed between December 2011 and August 2013. The primary outcome measures were the average visual analog scale (VAS) pain score and the percent of VAS pain scores that indicated no pain. Multivariable regression analyses investigated the effect of age, race, ethnicity, body mass index, gender, surgeon, and analgesic protocol on outcomes. For the analgesic groups, the "PAI" group received injections of a cocktail including bupivacaine, ketorolac, and morphine, whereas the "LBUP" group received injections of LBUP.

RESULTS

The regression analysis demonstrated that postoperative pain was higher in females (P < .001) and younger patients (P < .001). Although overall average VAS pain scores were not significantly different, when specific postoperative days were evaluated, the LBUP group had lower pain scores from day 1 to 5 (P < .014). There were no differences in VAS scores based on patient body mass index (P = .250), race (P = .205), or ethnicity (P = .961) in this sample.

CONCLUSION

This multivariate regression analysis study showed that in patients undergoing primary TKA, postoperative pain was lower in males, older patients, and those treated with LBUP. Awareness of these factors may assist in developing patient-specific multimodal postoperative pain and education protocols that reduce opioid reliance and related adverse events.

The use of patient-reported outcomes after routine arthroplasty: beyond the whys and ifs

The limitations and benefits of patient-reported outcome measures, in defining the merits of arthroplasty surgery, are discussed.

The influence of diabetes mellitus on the post-operative outcome of elective primary total knee replacement: a systematic review and meta-analysis

Total knee replacement (TKR) is an effective method of treating end-stage arthritis of the knee. It is not, however, a procedure without risk due to a number of factors, one of which is diabetes mellitus. The purpose of this study was to estimate the general prevalence of diabetes in patients about to undergo primary TKR and to determine whether diabetes mellitus adversely affects the outcome. We conducted a systematic review and meta-analysis according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. The Odds Ratio (OR) and mean difference (MD) were used to represent the estimate of risk of a specific outcome. Our results showed the prevalence of diabetes mellitus among patients undergoing TKR was 12.2%. Patients with diabetes mellitus had an increased risk of deep infection (OR = 1.61, 95% confidence interval (CI), 1.38 to 1.88), deep vein thrombosis (in Asia, OR = 2.57, 95% CI, 1.58 to 4.20), periprosthetic fracture (OR = 1.89, 95% CI, 1.04 to 3.45), aseptic loosening (OR = 9.36, 95% CI, 4.63 to 18.90), and a poorer Knee Society function subscore (MD = -5.86, 95% CI, -10.27 to -1.46). Surgeons should advise patients specifically about these increased risks when obtaining informed consent and be meticulous about their peri-operative care.

The natural history of pain and neuropathic pain after knee replacement: a prospective cohort study of the point prevalence of pain and neuropathic pain to a minimum three-year follow-up

A small proportion of patients have persistent pain after total knee replacement (TKR). The primary aim of this study was to record the prevalence of pain after TKR at specific intervals post-operatively and to ascertain the impact of neuropathic pain. The secondary aim was to establish any predictive factors that could be used to identify patients who were likely to have high levels of pain or neuropathic pain after TKR. A total of 96 patients were included in the study. Their mean age was 71 years (48 to 89); 54 (56%) were female. The mean follow-up was 46 months (39 to 51). Pre-operative demographic details were recorded including a Visual Analogue Score (VAS) for pain, the Hospital Anxiety and Depression score as well as the painDETECT score for neuropathic pain. Functional outcome was assessed using the Oxford Knee score. The mean pre-operative VAS was 5.8 (1 to 10); and it improved significantly at all time periods post-operatively (p < 0.001): (from 4.5 at day three to five (1 to 10), 3.2 at six weeks (0 to 9), 2.4 at three months (0 to 7), 2.0 at six months (0 to 9), 1.7 at nine months (0 to 9), 1.5 at one year (0 to 8) and 2.0 at mean 46 months (0 to 10)). There was a high correlation (r > 0.7; p < 0.001) between the mean VAS scores for pain and the mean painDETECT scores at three months, one year and three years post-operatively. There was no correlation between the pre-operative scores and any post-operative scores at any time point. We report the prevalence of pain and neuropathic pain at various intervals up to three years after TKR. Neuropathic pain is an underestimated problem in patients with pain after TKR. It peaks at between six weeks and three-months post-operatively. However, from these data we were unable to predict which patients are most likely to be affected.