The Oxford knee score and its subscales do not exhibit a ceiling or a floor effect in knee arthroplasty patients: an analysis of the National Health Service PROMs data set

Overcoming floor and ceiling effects in knee arthroplasty outcome measurement

Aims

To map the Oxford Knee Score (OKS) and High Activity Arthroplasty Score (HAAS) items to a common scale, and to investigate the psychometric properties of this new scale for the measurement of knee health.

Methods

Patient-reported outcome measure (PROM) data measuring knee health were obtained from the NHS PROMs dataset and Total or Partial Knee Arthroplasty Trial (TOPKAT). Assumptions for common scale modelling were tested. A graded response model (fitted to OKS item responses in the NHS PROMs dataset) was used as an anchor to calibrate paired HAAS items from the TOPKAT dataset. Information curves for the combined OKS-HAAS model were plotted. Bland-Altman analysis was used to compare common scale scores derived from OKS and HAAS items. A conversion table was developed to map between HAAS, OKS, and the common scale.

Results

We included 3,329 response sets from 528 patients undergoing knee arthroplasty. These generally met the assumptions of unidimensionality, monotonicity, local independence, and measurement invariance. The HAAS items provided more information than OKS items at high levels of knee health. Combining both instruments resulted in higher test-level information than either instrument alone. The mean error between common scale scores derived from the OKS and HAAS was 0.29 logits.

Conclusion

The common scale allowed more precise measurement of knee health than use of either the OKS or HAAS individually. These techniques for mapping PROM instruments may be useful for the standardization of outcome reporting, and pooling results across studies that use either PROM in individual-patient meta-analysis.

Not all questions are created equal: the weight of the Oxford Knee Scores questions in a multicentric validation study

BACKGROUND

The Oxford Knee Score (OKS) has been designed for patients with knee osteoarthritis and has a widespread use. It has 12 questions, with each question having the same weight for the overall score. Some authors have observed a significant ceiling effect, especially when distinguishing slight postoperative differences. We hypothesized that each questions' weight will depend significantly on the patient's sociodemographic data and lifestyle.

METHODS

In this international multicentric prospective study, we included patients attending a specialist outpatient knee clinic. Each patient filled out 3 questionnaires: (a) demographic data and data pertaining to the OKS, (b) the standard OKS, and (c) the patient gave a mark on the weight of the importance of each question, using a 5-point Likert scale (G OKS). Linear regression models were used for the analysis.

RESULTS

In total 203 patients (106 female and 97 male) with a mean age of 64.5 (±12.7) years and a mean body mass index (BMI) of 29.34 (±5.45) kg/m2 were included. The most important questions for the patients were the questions for pain, washing, night pain, stability, and walking stairs with a median of 5. In the regression models, age, gender, and driving ability were the most important factors for the weight of each of the question.

CONCLUSION

The questions in the OKS differ significantly in weight for each patient, based on sociodemographic data, such as age, self-use of a car, and employment. With these differences, the Oxford Knee Score might be limited as an outcome measure. Adjustment of the OKS that incorporates the demographic differences into the final score might be useful if the ceiling effect is to be mitigated.

LEVEL OF EVIDENCE

Level II prospective prognostic study.

Cooled radiofrequency ablation versus cryoneurolysis of the genicular nerves for the symptomatic pain management in knee osteoarthritis: a study protocol of a prospective, randomized, single-blinded clinical trial

BACKGROUND

Cooled radiofrequency ablation (CRFA) and cryoneurolysis (CRYO) are two novel methods of genicular neurolysis to relief pain in symptomatic knee osteoarthritis (KOA). In this study, the two methods will be compared, giving us the opportunity to investigate their efficacy, safety and complications.

METHODS

In this prospective randomized trial 70 patients with KOA will be recruited using a diagnostic block of four genicular nerves. Two groups will be created through software randomization: a CRFA group (35 patients) and a CRYO group (35 patients). The target of the interventions will be four genicular nerves; the superior medial, superior lateral, inferior medial, as well as the medial (retinacular) genicular branch from vastus intermedius. The primary outcome of this clinical trial will be the efficacy of CRFA or CRYO at 2-, 4-, 12-and 24-weeks post-intervention using the Numerical Rating Pain Scale (NRPS). The secondary outcomes are the safety of the two techniques, as well as the clinical evaluation using the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford Knee Score (OKS), and the 7-point scale of Patient Global Impression of Change (PGIC).

DISCUSSION

These two novel techniques can block pain transmission through genicular nerves in different ways. In contrast to cryoneurolysis, the CRFA method has been well documented in the past. This is the first clinical trial to compare CRFA vs CRYO and draw conclusions about their safety and efficacy.

TRIAL REGISTRATION

ISRCTN87455770 [ https://doi.org/10.1186/ISRCTN87455770 ]. Registered 29/3/2022, first patient recruited 31/8/2022.

Metabolic equivalent of task scores avoid the ceiling effect observed with conventional patient-reported outcome scores following knee arthroplasty

The metabolic equivalent of task (MET) score examines patient performance in relation to energy expenditure before and after knee arthroplasty. This study assesses its use in a knee arthroplasty population in comparison with the widely used Oxford Knee Score (OKS) and EuroQol five-dimension index (EQ-5D), which are reported to be limited by ceiling effects. A total of 116 patients with OKS, EQ-5D, and MET scores before, and at least six months following, unilateral primary knee arthroplasty were identified from a database. Procedures were performed by a single surgeon between 2014 and 2019 consecutively. Scores were analyzed for normality, skewness, kurtosis, and the presence of ceiling/floor effects. Concurrent validity between the MET score, OKS, and EQ-5D was assessed using Spearman's rank. Postoperatively the OKS and EQ-5D demonstrated negative skews in distribution, with high kurtosis at six months and one year. The OKS demonstrated a ceiling effect at one year (15.7%) postoperatively. The EQ-5D demonstrated a ceiling effect at six months (30.2%) and one year (39.8%) postoperatively. The MET score did not demonstrate a skewed distribution or ceiling effect either at six months or one year postoperatively. Weak-moderate correlations were noted between the MET score and conventional scores at six months and one year postoperatively. In contrast to the OKS and EQ-5D, the MET score was normally distributed postoperatively with no ceiling effect. It is worth consideration as an arthroplasty outcome measure, particularly for patients with high expectations.

Measurement properties of PROMIS short forms for pain and function in patients receiving knee arthroplasty

BACKGROUND

While there are a few studies on measurement properties of PROMIS short forms for pain and function in patients with knee osteoarthritis, nothing is known about the measurement properties in patients with knee arthroplasty. Therefore, this study examined the measurement properties of the German Patient-Reported Outcomes Measurement Information System (PROMIS) short forms for pain intensity (PAIN), pain interference (PI) and physical function (PF) in knee arthroplasty patients.

METHODS

Short forms were collected from consecutive patients of our clinic's knee arthroplasty registry before and 12 months post-surgery. Oxford Knee Score (OKS) was the reference measure. A subsample completed the short forms twice to test reliability. Construct validity and responsiveness were assessed using scale-specific hypothesis testing. For reliability, Cronbach's alpha, intraclass correlation coefficients, and agreement using standard error of measurement (SEM_agr) were used. Agreement was used to determine standardised effect sizes and smallest detectable changes (SDC90). Individual-level minimal important change (MIC) was calculated using a method of adjusted prediction.

RESULTS

Of 213 eligible patients, 155 received questionnaires, 143 returned baseline questionnaires and 119, 12-month questionnaires. Correlations of short forms with OKS were large (│r│ ≥ 0.7) with slightly lower values for PAIN, and specifically for men. Cronbach's alpha values were ≥ 0.84 and intraclass correlation coefficients ≥ 0.90. SEM_agr were around 3.5 for PAIN and PI and 1.7 for PF. SDC90 were around 8 for PAIN and PI and 4 for PF. Follow-up showed a relevant ceiling effect for PF. Correlations with OKS change scores of around 0.5 to 0.6 were moderate. Adjusted MICs were 7.2 for PAIN, 3.5 for PI and 5.7 for PF.

CONCLUSION

Our results partly support the use of the investigated short forms for knee arthroplasty patients. The ability of PF to differentiate between patients with high perceived recovery is limited. Therefore, the advantages and disadvantages should be strongly considered within the context of the intended use.

Patella resurfacing is not associated with a difference in the Oxford knee score after total knee arthroplasty but stair descent is enhanced

BACKGROUND

The primary aim was to assess the Oxford knee scores (OKS) on patients who underwent a total knee arthroplasty (TKA) with patellar resurfacing compared to those who did not. Secondary aims were to identify: (1) factors associated with resurfacing, (2) the effect of resurfacing on specific components of the OKS related to patellofemoral function, (3) the influence on patient satisfaction, and (4) whether a subgroup of patients had an improved outcome when resurfacing was undertaken.

METHODS

A retrospective cohort study was undertaken using outcome data from the arthroplasty database held at the study centre. Patient demographics and OKS were collected preoperatively and at 1 and 2 years postoperatively. Patient satisfaction was assessed at 1 and 2 years postoperatively.

RESULTS

Three thousand one hundred and twenty-two patients met the inclusion criteria of which 46.5% (n = 1453) underwent resurfacing. There were no differences in the OKS change at 1 or 2 years between those undergoing and not undergoing resurfacing (difference 0.2, p ≥ 0.469). Patients undergoing resurfacing were more likely to be female (odds ratio (OR) 1.53, 95% CI 1.30-1.79, p < 0.001), undergo a posterior stabilised knee (OR 6.87, 95% CI 5.71-8.27, p < 0.001) or had a worse response to question 5-standing from a chair, (p = 0.011) or 12-stair descent, (p = 0.017) of the OKS preoperatively. There was no difference in postoperative patient satisfaction (p ≥ 0.180). There was a significantly greater improvement in question 12 of the OKS at 1 year (p = 0.019) in the resurfaced group. There were no patient-related factors or symptoms that were associated with a clinically significant (≥ 5 points) greater postoperative OKS.

CONCLUSION

Patella resurfacing was not associated with a clinically important improvement in OKS. No specific indications for patella resurfacing were identified that offered an improved outcome, but when it was undertaken there was a greater improvement in the ability to descend stairs. Level of evidence Retrospective diagnostic study, Level III.

Association between VTE and antibiotic prophylaxis guideline compliance and patient-reported outcomes after total hip and knee arthroplasty: an observational study

BACKGROUND

Surgical site infection (SSI) and venous thromboembolism (VTE) are associated with high burden and cost and are considered largely preventable following total knee or hip arthroplasty (TKA, THA). The risk of developing VTE and SSI is reduced when prophylaxis is compliant with evidence-based clinical guidelines. However, the association between VTE and antibiotic prophylaxis clinical guideline compliance and patient-reported outcome measures (PROMs) after THA/TKA is unknown. This study aims to explore whether care that is non-compliant with VTE and antibiotic guideline recommendations is associated with PROMs (Oxford Hip/Knee Score and EQ-5D Index scores) at 90- and 365-days after surgery.

METHODS

This prospective observational study included high-volume arthroplasty public and private sites and consenting eligible participants undergoing elective primary THA/TKA. We conducted multiple linear regression and linear mixed-effects modelling to explore the associations between non-compliance with VTE and antibiotic guidelines, and PROMs.

RESULTS

The sample included 1838 participants. Compliance with VTE and antibiotic guidelines was 35% and 13.2% respectively. In adjusted modelling, non-compliance with VTE guidelines was not associated with 90-day Oxford score (β = - 0.54, standard error [SE] = 0.34, p = 0.112) but was significantly associated with lower (worse) 365-day Oxford score (β = - 0.76, SE = 0.29, p = 0.009), lower EQ-5D Index scores at 90- (β = - 0.02 SE = 0.008, p = 0.011) and 365-days (β = - 0.03, SE = 0.008, p = 0.002).. The changes in Oxford and EQ-5D Index scores were not clinically important. Noncompliance with antibiotic guidelines was not associated with either PROM at 90- (Oxford: β = - 0.45, standard error [SE] = 0.47, p = 0.341; EQ-5D: β = - 0.001, SE = 0.011, p = 0.891) or 365-days (Oxford score: β = - 0.06, SE = 0.41, p = 0.880 EQ-5D: β = - 0.010, SE = 0.012, p = 0.383). Results were consistent when complications were included in the model and in linear mixed-effects modelling with the insurance sector as a random effect.

CONCLUSIONS

Non-compliance with VTE prophylaxis guidelines, but not antibiotic guidelines, is associated with statistically significant but not clinically meaningful differences in Oxford scores and EQ-5D Index scores at 365 days.

Comparison of the clinical and patient-reported outcomes between medial stabilized and posterior stabilized total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Total knee arthroplasty (TKA) is effective in relieving pain and improving function in patients with end-stage knee osteoarthritis. Both medial stabilized total knee arthroplasty (MS-TKA) and posterior stabilized total knee arthroplasty (PS-TKA) can achieve satisfactory clinical results, but comparisons between MS-TKA and PS-TKA have yielded contradictory conclusions. This systematic review and meta-analysis were performed to investigate the differences in clinical and patient-reported outcomes (PROMs) between MS-TKA and PS-TKA.

METHODS

In December 2020, systematic searches of the following databases were undertaken: Pubmed, Embase, Cochrane Library, Clinical Trials.gov. Studies with PROMs comparing MS-TKA to PS-TKA were included. Meta-analysis was conducted for range of motion (ROM), Knee Society Score (KSS), Knee Society Functional Score (KFS), Forgotten Joint Score (FJS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Oxford Knee Score (OKS).

RESULTS

There were 17 studies included in this review, 13 studies used for quantitative analysis, and 4 studies used for qualitative synthesis. Meta-analysis concluded that the WOMAC mean difference (MD) for MS-TKA was 1.55 higher than for PS-TKA (MD = -1.55; 95 %CI = -2.45 to -0.64, P = 0.0008); however, this difference was less than the minimum clinically important difference (MCID) value of 15. Assessment using the OKS determined that the MD for PS-TKA was 0.58 higher than for MS-TKA (MD = 0.58; 95 %CI = 0.25 to 0.91, P = 0.0006); again, this MD was less than the MCID value of 5. There were no significant differences between MS-TKA and PS-TKA when assessed by ROM (P = 0.23), KSS (P = 0.13), KFS (P = 0.61), or FJS (P = 0.22).

CONCLUSION

Derived from numerous sources, utilizing a multitude of validated functional and patient-reported outcome assessment tools, there was no clinically evident advantage of MS-TKA compared to PS-TKA.

REGISTRATION

The registration number on PROSPERO is CRD42021228555.

Medial stabilised total knee arthroplasty achieves comparable clinical outcomes when compared to other TKA designs: a systematic review and meta-analysis of the current literature

PURPOSE

The purpose of this study was to perform a systematic review and meta-analysis to compare clinical and patient-reported outcome measures of medially stabilised (MS) TKA when compared to other TKA designs.

METHODS

The Preferred Reporting Items for Systematic Review and Meta-Analyses algorithm was used. The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and EMCARE databases were searched to June 2020. Studies with a minimum of 12 months of follow-up comparing an MS TKA design to any other TKA design were included. The statistical analysis was completed using Review Manager (RevMan), Version 5.3.

RESULTS

The 22 studies meeting the inclusion criteria included 3011 patients and 4102 TKAs. Overall Oxford Knee Scores were significantly better (p = 0.0007) for MS TKA, but there was no difference in the Forgotten Joint Scores (FJS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS)-Knee, KSS-Function, and range of motion between MS and non-MS TKA designs. Significant differences were noted for sub-group analyses; MS TKA showed significantly worse KSS-Knee (p = 0.02) and WOMAC (p = 0.03) scores when compared to Rotating Platform (RP) TKA while significantly better FJS (p = 0.002) and KSS-knee scores (p = 0.0001) when compared to cruciate-retaining (CR) TKA.

CONCLUSION

This review and meta-analysis show that MS TKA designs result in both patient and clinical outcomes that are comparable to non-MS implants. These results suggest implant design alone may not provide further improvement in patient outcome following TKA, surgeons must consider other factors, such as alignment to achieve superior outcomes.

LEVEL OF EVIDENCE

III.

Presenteeism and work ability: development of the Persian version of the Stanford Presenteeism Scale (P-SPS-6) and measurement of its psychometric properties

Background

Presenteeism is recognized in Iran’s hospitals, however little research has been done to understand and tackle the phenomenon because of a lack of valid tools to measure presenteeism. This study aimed to develop a Persian version of the Stanford Presenteeism Scale (SPS-6) and measure its psychometric properties. Another goal was to examine the relationship between presenteeism and work ability using a sample of 250 nurses.

Methods

The forward–backward translation process and cross-cultural adaptation of the scale were performed according to a standard method. The psychometric properties of the scale were measured using face and content validity, construct validity based on confirmatory factor analysis (CFA), and internal consistency. Work ability score (WAS) was used to assess discriminative validity and examine the relationship between presenteeism and work ability. Measures of Job Satisfaction and Emotional Exhaustion were used to assess convergent validity with the developed presenteeism scale.

Results

Mean content validity index and content validity ratio were 1 and 0.93 respectively. CFA verified the two-dimensional structure of the scale. Cronbach's alpha was 0.77. There were positive relationships between P-SPS-6 and Job Satisfaction, and P-SPS-6 and WAS. There was a significant negative relationship between P-SPS-6 and Emotional Exhaustion.

Conclusion

Our findings suggested that the P-SPS-6 had appropriate psychometric properties for studying presenteeism in employees using the Persian language. Given the negative relationship between presenteeism and work ability and the negative consequences associated with it, it is necessary to regularly evaluate this stressor and to emphasize purposeful intervention programs to control or reduce it.

Evidence for the validity of a patient-based instrument for assessment of outcome after revision knee arthroplasty

AIMS

To estimate the measurement properties for the Oxford Knee Score (OKS) in patients undergoing revision knee arthroplasty (responsiveness, minimal detectable change (MDC-90), minimal important change (MIC), minimal important difference (MID), internal consistency, construct validity, and interpretability).

METHODS

Secondary data analysis was performed for 10,727 patients undergoing revision knee arthroplasty between 2013 to 2019 using a UK national patient-reported outcome measure (PROM) dataset. Outcome data were collected before revision and at six months postoperatively, using the OKS and EuroQol five-dimension score (EQ-5D). Measurement properties were assessed according to COnsensus-based Standards for the selection of health status Measurement Instruments (COSMIN) guidelines.

RESULTS

A total of 9,219 patients had complete outcome data. Mean preoperative OKS was 16.7 points (SD 8.1), mean postoperative OKS 29.1 (SD 11.4), and mean change in OKS + 12.5 (SD 10.7). Median preoperative EQ-5D index was 0.260 (interquartile range (IQR) 0.055 to 0.691), median postoperative EQ-5D index 0.691 (IQR 0.516 to 0.796), and median change in EQ-5D index + 0.240 (IQR 0.000 to 0.567). Internal consistency was good with Cronbach's α 0.88 (baseline) and 0.94 (post-revision). Construct validity found a high correlation of OKS total score with EQ-5D index (r = 0.76 (baseline), r = 0.83 (post-revision), p < 0.001). The OKS was responsive with standardized effect size (SES) 1.54 (95% confidence interval (CI) 1.51 to 1.57), compared to SES 0.83 (0.81 to 0.86) for the EQ-5D index. The MIC for the OKS was 7.5 points (95% CI 5.5 to 8.5) based on the optimal cut-off with specificity 0.72, sensitivity 0.60, and area under the curve 0.66. The MID for the OKS was 5.2 points. The MDC-90 was 3.9 points. The OKS did not demonstrate significant floor or ceiling effects.

CONCLUSION

This study found that the OKS was a useful and valid instrument for assessment of outcome following revision knee arthroplasty. The OKS was responsive to change and demonstrated good measurement properties. Cite this article: Bone Joint J 2021;103-B(4):627-634.

The Medical Gloves Assessment Tool (MGAT): Developing and validating a quantitative tool for assessing the safety and ergonomic features related to medical gloves

BACKGROUND

Medical gloves play a very important role in protecting health care workers and patients. It is very important to pay attention to the safety and ergonomic properties of medical gloves in their protective function.

AIM

To develop a quantitative tool for evaluating the safety and ergonomic properties of the medical gloves.

METHODS

Five hospitals with a total of 185 health care workers participated in the research. The domains and items of the tool were developed based on an expert's panel, interviews with health care workers and a literature review. Face, content and construct validity was used for validation. Reliability was also evaluated using internal consistency.

RESULTS

The final tool included 26 items in six domains, including tactile sensation, dexterity, grip strength, fitting, reliability and hand hygiene. The Cronbach's alpha was 0.82 for the total scale.

CONCLUSION

The final tool had good validity and reliability. The findings of this study led to the development of a comprehensive standard tool that can be used to assess the ergonomic and safety status of medical gloves.

IMPLICATIONS FOR NURSING MANAGEMENT

With this tool, problems related to medical gloves can be identified among nurses, and the necessary interventions can be predicted.

Translation and Validation of the Hospital for Special Surgery Pediatric Functional Activity Brief Scale for French Paediatric Populations

Purpose: Physical activity level is a prognostic variable for patients with injuries. Self-report questionnaires exist to obtain these measures; however, they are not accessible to all populations because of language barriers. Therefore, the purpose of this study was to translate and validate the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) for francophones. Method: We translated the HSS Pedi-FABS using the forward–reverse translation approach and validated it among bilingual adults and an expert panel before administering it to a paediatric population. A repeated-measures crossover design was used: forty-three middle school students, aged 13.1 (SD 0.75) years, were randomly administered either the English or the French questionnaire. Two days later, all participants completed the other version. The translated questionnaire was assessed for its convergent validity (Spearman’s r correlation coefficients [ rs]), internal consistency (Cronbach’s α), and reliability (standard error of measurement [SEM]). Results: All assessments had a significance level of p < 0.001 with an excellent Spearman’s r correlation coefficient between the participants’ total scores on the translated questionnaires ( rs = 0.911). The overall scores for the questionnaire and the individual items of the questionnaire revealed excellent internal consistency (α = 0.868) and reliability (SEM = 0.334). Conclusions: The validated and reliable translated questionnaire can be used by researchers and clinicians to assess physical activity levels in French paediatric populations.

The preoperative Oxford Knee Score is an independent predictor of achieving a postoperative ceiling score after total knee arthroplasty

Aims

The primary aim of this study was to assess whether the postoperative Oxford Knee Score (OKS) demonstrated a ceiling effect at one and/or two years after total knee arthroplasty (TKA). The secondary aim was to identify preoperative independent predictors for patients that achieved a ceiling score after TKA.

Methods

A retrospective cohort of 5,857 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, body mass index (BMI), OKS, and EuroQoL five-dimension (EQ-5D) general health scores were collected preoperatively and at one and two years postoperatively. Logistic regression analysis was used to identify independent preoperative predictors of patients achieving postoperative ceiling scores. Receiver operating characteristic curve was used to identify a preoperative OKS that predicted a postoperative ceiling score.

Results

The ceiling effect was 4.6% (n = 272) at one year which increased significantly (odds ratio (OR) 40.3, 95% confidence interval (CI) 30.4 to 53.3; p < 0.001) to 6.2% (n = 363) at two years, when defined as those with a maximal score of 48 points. However, when the ceiling effect was defined as an OKS of 44 points or more, this increased to 26.3% (n = 1,540) at one year and further to 29.8% (n = 1,748) at two years (OR 21.6, 95% CI 18.7 to 25.1; p < 0.001). A preoperative OKS of 23 or more and 22 or more were predictive of achieving a postoperative ceiling OKS at one and two years when defined as a maximal score or a score of 44 or more, respectively.

Conclusion

The postoperative OKS demonstrated a small ceiling effect when defined by a maximal score, but when defined by a postoperative OKS of 44 or more the ceiling effect was moderate and failed to meet standards. The preoperative OKS was an independent predictor of achieving a ceiling score. Cite this article: Bone Joint J 2020;102-B(11):1519–1526.

Cross-Cultural Adaptation of the Greek Versions of the Lysholm Knee Scoring Scale and Tegner Activity Scale

Purpose

The Lysholm Knee Scoring Scale (LKSS) and the Tegner Activity Scale (TAS) are widely used instruments for assessing knee function and activity level in various knee pathologies, especially knee ligament injuries. The purpose of this study was to translate and cross-culturally adapt the Greek versions of the Lysholm Knee Scoring Scale (Gr-LKSS) and Tegner Activity Scale (Gr-TAS) and assess their reliability and validity in Greek patients suffering from various knee problems.

Materials and methods

Translation of the LKSS and TAS questionnaires was done according to established international guidelines. Fifty-five patients (32 males and 23 females; mean age: 24 ±7 years; range: 17-54 years) with various knee pathologies completed the Gr-LKSS and Gr-TAS along with the Greek versions of International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, the Knee Outcome Survey Activities of Daily Living Scale (KOS-ADLS) and the Oxford Knee Score (OKS). Test-retest reliability was evaluated with the intraclass correlation coefficient (ICC) in 53 (96%) individuals, who completed the questionnaires again after 48-72 hours while abstaining from all forms of treatment. Internal consistency for the Gr-LKSS was measured using Cronbach’s alpha and criterion-related validity was evaluated with the Pearson's correlation coefficient (r) in relation to control questionnaires (IKDC, KOS-ADLS, OKS). The distribution of floor and ceiling effects were also determined.

Results

There were no problems during the forward-backward translation and cultural adaptation of the Gr-LKSS and Gr-TAS. Criterion-related validity was confirmed with moderate to high associations of Gr-LKSS and Gr-TAS (after injury) with the IKDC and KOS-ADLS (Pearson’s r ranging between 0.61-0.71 and 0.64-0.73, respectively). However, weak correlations were yielded between both questionnaires with the OKS (r=0.14-0.19). The internal consistency for Gr-LKSS was high (Cronbach's alpha: 0.779) and the test-retest reliability was high for both questionnaires (Gr-LKSS: ICC=0.950; Gr-TAS before and after injury: ICCs of 0.877 and 0.876, respectively).

Conclusion

The cultural adaptation and validity of Gr-LKSS and Gr-TAS were successfully accomplished. These questionnaires are recommended for use in the evaluation of soft tissue knee disorders in both clinical practice and research.

Outcomes of Computer-Assisted Surgery Compared with Conventional Instrumentation in 19,221 Total Knee Arthroplasties: Results After a Mean of 4.5 Years of Follow-Up

BACKGROUND

Studies have shown improved alignment in association with the use of computer-assisted surgery (CAS) as compared with conventional instrumentation during total knee arthroplasty (TKA) but have failed to show a consistent clinical benefit. The aim of the present study was to compare the revision rates and functional outcomes following TKA performed with either CAS or conventional instrumentation. Recognizing that selection bias may arise from the preferential use of CAS in difficult or complex cases, the implant survival data and postoperative functional scores were analyzed with reference to whether the surgeon routinely performed TKA with use of CAS or conventional instrumentation.

METHODS

Revision rates and functional data in terms of the Oxford Knee Score (OKS) at 6 months, 5 years, and 10 years were obtained from the New Zealand Joint Registry (NZJR) for 19,221 TKAs performed from 2006 to 2018.These data were analyzed by comparing 2 cohorts of patients: those managed by high-volume surgeons who routinely used CAS ("routine CAS" surgeons) and those managed by high-volume surgeons who routinely used conventional instrumentation ("routine conventional" surgeons). The mean duration of follow-up was 4.5 years (range, 0 to 12 years).

RESULTS

The revision rate per 100 component-years was 0.437 for the "routine CAS" surgeons, compared with 0.440 for the "routine conventional" surgeons (p = 0.724). For patients <65 years of age, the revision rate per 100 component-years was equivalent for the "routine CAS" and "routine conventional" surgeons (0.585 compared with 0.508; p = 0.524). The OKS scores were similar at 6 months (38.88 compared with 38.52; p = 0.172), 5 years (42.26 compared with 41.77; p = 0.206), and 10 years (41.59 compared with 41.74; p = 0.893) when comparing the 2 cohorts. Surgeons who had performed >50 TKAs with use of CAS took 10 minutes longer on average than those who used conventional instrumentation (92 compared with 82 minutes; p = 0.012).

CONCLUSIONS

The present study demonstrated no difference in survivorship or functional outcome scores to support using CAS for TKA. Experienced surgeons using CAS had longer operative durations than comparable surgeons using conventional instrumentation.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Unicondylar knee arthroplasty following a patellectomy

We present a case of a 59-year-old woman with a history of a right-sided patellectomy. She presented with right-sided anteromedial osteoarthritis. A unicondylar knee arthroplasty was performed. In the literature, we found only a few similar cases, with varying results. The woman in this case showed excellent postoperative clinical results. We concluded that a patellectomy may not be a contraindication for unicondylar knee arthroplasty in patients with isolated medial compartment osteoarthritis.

Pain relieve without impairing muscle function after local infiltration anaesthesia in primary knee arthroplasty: a prospective randomized study

PURPOSE

Purpose of the current study was to compare early effectiveness of pain relieve of 3 in 1 regional pain catheter to local infiltration anesthesia (LIA) in primary total knee arthroplasty (TKA). Secondary endpoint was quadriceps muscle strength after both procedures.

MATERIAL AND METHODS

A single-center, prospective, randomized controlled trial was performed. Patients eligible to TKA were either randomized into group 3 in 1 regional pain catheter (C), or group local infiltration anesthesia (L). Pain relieve was assessed by visual analogue scale (VAS) at rest and under physical activity (PA) prior to surgery (t0) and at days one through six. In addition, quadriceps muscle strength ( = straight leg raise) was tested according to the Manual Muscle Testing Scale. Functional outcome was measured using the Oxford Knee Score (OKS) preoperatively and 6 months postoperatively.

RESULTS

121 patients were included in the study. 59 (48.8%) patients were allocated to group C, 62 (51.2%) patients to Group L. No differences concerning pain level evaluated by VAS could be detected between the groups at any time. Comparing straight leg raise test group L was significantly superior over the complete postoperative period (p < 0.03). The mean OKS decreased significantly (p < 0.001) from preoperatively 34.2 ± 7.5 points to 16.9 ± 6.0 points at the six months final follow-up. Regarding OKS there were no intergroup differences at the final follow-up at 6 months postoperative.

CONCLUSION

There is no significant difference in pain relieve comparing LIA to 3 in 1 catheter in perioperative pain management in TKA. The advantage of LIA is unimpaired quadriceps muscle function in the short-term follow-up.

An Overview and Predictors of Achieving the Postoperative Ceiling Effect of the WOMAC Score Following Total Knee Arthroplasty

BACKGROUND

To describe the ceiling effect for the components of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and identify preoperative independent predictors for patients who achieve maximal scores (ceiling effect) after total knee arthroplasty (TKA).

METHODS

A retrospective cohort of 2589 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, WOMAC and Short Form 12 (SF-12) scores were collected preoperatively and 1 year postoperatively. Logistic regression analysis was used to identify independent preoperative predictors of patients achieving ceiling scores.

RESULTS

The ceiling effect was 26.8% (n = 695) for the pain score, 6.4% (n = 165) for the function score, and 21.2% (n = 548) for the stiffness score. Lower body mass index (P = .001), absence of gastric ulceration (P = .04), absence of anemia (P = .02), absence of depression (P = .004), and absence of back pain (P < .001) and better preoperative WOMAC pain and SF-12 physical (P = .01) and mental (P < .001) scores were associated with a ceiling WOMAC pain score. Male gender (P = .03), lower body mass index (P = .040), absence of gastric ulceration (P = .004), and absence of back pain (P < .001) and better preoperative SF-12 physical (P = .02) scores were associated with a ceiling WOMAC function score. Male gender (P = .001), absence of back pain (P < .001), and better preoperative WOMAC stiffness score (P = .005) and SF-12 mental (P = .001) scores were associated with a ceiling WOMAC stiffness score.

CONCLUSION

The WOMAC pain and stiffness components demonstrated a high ceiling effect but in contrast the functional score had a low ceiling effect. The absence of back pain was a common predictive factor for all 3 components and had the greatest impact upon the likelihood of achieving a ceiling score.