Joint awareness in osteoarthritis of the hip and knee evaluated with the 'Forgotten Joint' Score before and after joint replacement

Good Short-Term Survivorship of Constrained Condylar Revision Knee Implants With Medial Pivot Kinematics: A Level IV Retrospective Study

BACKGROUND

The need for revision total knee arthroplasty surgery is increasing worldwide, and, in many cases, a constrained implant is required to provide joint stability. The purpose of this study was to examine the early loosening and functional outcome of a novel constrained condylar (CCK) revision total knee system designed to have medial pivot (MP) kinematics.

METHODS

A retrospective cohort study was performed, collecting clinical data from all patients who underwent revision total knee arthroplasty using a novel MP CCK system with a minimum four-year clinical follow-up. Patient demographics, survivorship, complications, and Forgotten Joint Score were analyzed based upon chart review.

RESULTS

There were 49 patients available for follow-up, who had a 100% survivorship free of aseptic loosening. All-cause revision survivorship was 92%. There were 4 patients who subsequently underwent rerevision. The causes for rerevision included periprosthetic joint infection in 2 patients, coronal plane instability in one patient, and a traumatic knee dislocation in one patient. There were 45 patients who completed the Forgotten Joint Score, who had an average of 49.8 (± 32.8, range 6.25 to 100).

CONCLUSIONS

At 4 years, mid-term follow-up, this novel CCK revision total knee system designed to have MP kinematics had good patient-reported outcomes with no revision for aseptic loosening. Future studies should evaluate the mid- and long-term survivorship of this innovative implant.

Forgotten joint score associated with prosthesis weight in cementless total hip arthroplasty: a prospective clinical study

Background

This prospective study aimed to investigate the influence of weight difference between implanted prosthesis and removed bone in cementless total hip arthroplasty (THA) on hip awareness and patient-reported outcomes.

Methods

A total of 48 patients (56 hips) who underwent primary THA were prospectively enrolled. Implanted prosthesis and removed bone were weighed intraoperatively. Forgotten Joint Score (FJS) and Western Ontario and McMaster Universities (WOMAC) scores were obtained before and at 1 and 3 months after surgery. Patients were divided into groups A, B, and C according to the percentile of the weight difference.

Results

The mean weight difference of the implanted prosthesis and removed bone was 117.97 ± 47.35 g. A negative correlation was found among the weight differences of the three groups and 1- and 3-month postoperative FJS (correlation coefficients, -0.331 and -0.734, respectively). A positive correlation was found among the weight difference of the three groups and 3-month postoperative WOMAC (correlation coefficient, 0.403). A significant difference in 3-month postoperative FJS and WOMAC scores was found among the three groups. The mean 3-month postoperative FJS (79.00) of group C was significantly lower than that of group A (93.32) (P < 0.05). The mean WOMAC score (15.83) of group A was significantly lower than that of group C (23.67) (P < 0.05).

Conclusion

The implanted prosthesis is larger than the removed bone in cementless THA. The weight difference is negatively correlated with hip function. The weight difference should be minimized to achieve optimal hip joint awareness.

Item-reduced Forgotten Joint Score provides adequate psychometric properties in ACLR patients

Purpose

The purpose of this study was to evaluate content validity, test-retest reliability, internal consistency, construct validity, responsiveness and floor/ceiling effects of Forgotten Joint Score (FJS) for assessing functions in activities of daily living (ADL) following anterior cruciate ligament reconstruction (ACLR) and perform an item reduction of FJS.

Methods

Swedish-speaking ACLR patients in one surgical clinic were eligible. Content validity was evaluated through patient responses and patient and expert clinician relevance ratings, omitting items with low relevance. Principal component factor analysis, Cronbach's ⍺, paired t test, correlations between FJS and Knee Injury and Osteoarthritis Outcome Score (KOOS), Cohen's d effect sizes (ESs) and standardized response mean (SRM) were used to evaluate internal consistency, test-retest reliability, construct validity and responsiveness. Floor/ceiling effects were calculated. FJS was expected to reveal one dominant factor, a Cronbach's ⍺ between 0.70 and 0.95, correlations >0.50 to all KOOS subscores, highest for ADL, moderate ES and SRM, floor/ceiling effects <15%.

Results

One hundred and seventy-six participants (103 for assessing internal consistency, construct validity, responsiveness and floor/ceiling effects; 73 for assessing test-retest reliability and content validity) were included. Item reduction yielded a nine-item FJS (FJS-9). FJS-12 and FJS-9 demonstrated sufficient content validity (95% confidence interval [CI], 2.5-3.1, respectively, 2.9-3.3). FJS-9 was found unidimensional, and FJS-12 was multidimensional. Cronbach's ⍺ was 0.94 for FJS, and the intraclass correlation coefficient > 0.90. FJS showed significant correlations >0.65 to all KOOS subscales, moderate ES and SRM > 0.50. No floor/ceiling effects were found.

Conclusion

FJS-9 demonstrated adequate validity for the evaluation of joint awareness in ACLR patients and can be a valuable tool to assess ADL and joint awareness.

Level of Eidence

Level III.

Item Response Theory Validation of the Forgotten Joint Score for Persons Undergoing Total Knee Replacement

BACKGROUND

The Forgotten Joint Score (FJS), a commonly used patient-reported outcome measure, was developed without fully confirming assumptions such as unidimensionality (all items reflect 1 underlying factor), appropriate weighting of each item in scoring, absence of differential item functioning (in which different groups, e.g., men and women, respond differently), local dependence (pairs of items are measuring only 1 underlying factor), and monotonicity (persons with higher function have a higher score). We applied item response theory (IRT) to perform validation of the FJS according to contemporary standards, and thus support its ongoing use. We aimed to confirm that the FJS reflects a single latent trait. In addition, we aimed to determine whether an IRT model could be fitted to the FJS.

METHODS

Participants undergoing primary total knee replacement provided responses to the FJS items preoperatively and at 6 and 12 months postoperatively. An exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and Mokken analysis were conducted. A graded response model (GRM) was fitted to the data.

RESULTS

A total of 1,774 patient responses were analyzed. EFA indicated a 1-factor model (all 12 items reflecting 1 underlying trait). CFA demonstrated an excellent model fit. Items did not have equal weighting. The FJS demonstrated good monotonicity and no differential item functioning by sex, age, or body mass index. GRM parameters are reported in this paper.

CONCLUSIONS

The FJS meets key validity assumptions, supporting its use in clinical practice and research. The IRT-adapted FJS has potential advantages over the traditional FJS: it provides continuous measurements with finer granularity between health states, includes individual measurement error, and can compute scores despite more missing data (with only 1 response required to estimate a score). It can be applied retrospectively to existing data sets or used to deliver individualized computerized adaptive tests.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Systematic evaluation of the degree of joint amnesia in patients after total hip arthroplasty with direct anterior approach (DAA) compared with posterior approach (PA)

OBJECTIVE

A comparative study of joint amnesia in patients undergoing total hip arthroplasty with the direct anterior approach and posterior approach was conducted through a comprehensive evaluation.

METHODS

The literature on joint amnesia in postoperative patients who underwent total hip arthroplasty by the direct anterior approach and the posterior approach was systematically searched in PubMed, Embase, Web of Science, Cochrane Library, CNKI, CBM, Wanfang, and VIP databases from the time of library construction until February 13, 2023. Meta-analysis was performed using RevMan 5.3 software after independent searching, screening of the literature, data extraction, and quality assessment of the included studies by two investigators in strict accordance with the guidelines for conducting meta-analyses.

RESULTS

A total of one RCT and six cohort studies were included in this meta-analysis. Meta-analysis results indicated that at 1 month postoperatively (MD = 2.08, 95% CI (0.20, 3.96), P = 0.03), 3 months (MD = 10.08, 95% CI (1.20, 18.96), P = 0.03), and 1 year (MD = 6.74, 95% CI (1.30, 12.19), P = 0.02), DAA total hip arthroplasty was associated with better FJS compared to PA at 1 year postoperatively. However, there was no statistical significance in FJS between the two groups at 5 years postoperatively (MD = 1.35, 95% CI (- 0.58, 3.28), P = 0.17).

CONCLUSION

Current evidence suggests that the degree of joint amnesia after THA for DAA was not found to be superior to that of PA. Further, these findings require confirmation by including a larger number of high-quality randomized controlled studies.

STUDY DESIGN

Systematic review; Level of evidence, 3.

Sports activity participation and subjective health status of patients after total hip arthroplasty via the anterolateral-supine approach: a case series study

Background

No reports have been published about participation in sports activity and subjective health status after total hip arthroplasty via the anterolateral approach in the supine position (ALS-THA) in Japanese patients. This study assessed sports activity participation and subjective health status, as well as factors potential associated with these variables, in patients who underwent ALS-THA.

Methods

Of 698 patients who underwent total hip arthroplasty at our institution between 2013 and 2018, questionnaires were sent to 355 patients under 80 years old who had undergone ALS-THA and 242 responded. Patients were asked about their subjective health status, participation in sports activity, the EuroQol 5-dimensions 5-level (EQ-5D-5L), the University of California Los Angeles (UCLA) activity scale score and the Forgotten Joint Score (FJS). Patient characteristics and hospitalization information were also collected. Patients’ subjective health status was categorized as “healthy” or “unhealthy”. Univariate and multivariate logistic regression analyses were performed to determine factors associated with participation in sports activity after ALS-THA and a “healthy” status.

Results

The pre- and postoperative sports activity participation rates were 54.0% and 57.8%, respectively. Most patients (76.8%, n = 182) were considered “healthy”. Age (P = .019) and UCLA activity score (P < .001) were significantly associated with sports activity after ALS-THA. FJS (P = .002) and EQ-5D-5L (P = .004) were significantly associated with a “healthy” status.

Conclusion

Patients participating in sports activity after ALS-THA are older and have higher UCLA activity scores and patients considered “healthy” have higher FJS and EQ-5D-5L scores.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05886-6.

Arthroscopic-assisted robotic bi-unicompartmental knee arthroplasty: a pilot cadaveric study

INTRODUCTION

Although bicondylar arthroplasty showed great functional results, it encounters some difficulties to be performed routinely. On the other hand, arthroscopic techniques tend to replace open surgical techniques in sports medicine but strive to be developed in the field of arthroplasty. This study aimed to assess the feasibility of a micro-invasive bi-compartmental knee arthroplasty using both arthroscopic and robotic technologies (A-BiUKA).

MATERIALS AND METHODS

The study was conducted on complete fresh-frozen and embalmed cadaveric specimens. The main criterion of judgment was the successful positioning of trial implants through a minimal quad-sparing approach. Arthroscopy was used for bone-morphing and burring, supported by an image-free robotic system. Secondary criteria of judgment were axial deviation (measured using the navigation system), operating time, and incision length.

RESULTS

Ten A-BiUKA were performed. Implantation was successful in all cases. The mean preoperative frontal deviation was 179.8° ± 3.2 [175: 185], the mean postoperative frontal deviation was 178.5° ± 2.2 [175: 182], without any outliers. The mean correction was 1.7° ± 1.6 [0: 5]. Once the eight first A-UKA were performed, constituting the learning curve, the mean operative time for the remaining twelves surgeries was 90 min ± 6. The mean skin incision length was 3.35 cm ± 0.13 [3: 4].

CONCLUSION

Associated arthroscopic and robotic technologies allows to perform Bi-UKA procedure using a quad sparing mini-invasive approach. Clinical prospective studies have to confirm the feasibility and the clinical outcomes of this surgery.

Predictors of a forgotten joint after medial fixed-bearing unicompartmental knee arthroplasty

BACKGROUND

A forgotten joint is considered the ultimate goal of joint replacement. We aim to explore the predictive factors of a forgotten joint after fixed-bearing unicompartmental knee arthroplasty (UKA).

METHODS

This retrospective cohort study used prospectively collected data from 302 cases of medial-compartment UKA with a minimum of 2-year follow-up. The primary outcome was the achievement of a forgotten joint after UKA, according to the Forgotten Joint Score (FJS-12) at the last follow-up. Patients with FJS-12 > 84 were considered to have forgotten UKA. Univariate and multivariate logistic regression analyses were conducted with preoperative patient characteristics and surgery-related factors as potential predictors.

RESULTS

Of patients, 94 (31.1%) achieved a forgotten joint post-surgery. Multivariate logistic regression analysis revealed that preoperative hip-knee-ankle angle (HKAA), anatomic lateral distal femoral angle (aLDFA), and postoperative HKAA and HKAA changes were independent predictors of a forgotten joint. The probability of achieving a forgotten joint increased by 29% (OR = 1.29, 95% CI: 1.12-1.51) with a 1° increase in aLDFA. Preoperative HKAA, postoperative HKAA, HKAA changes (ΔHKAA), and outcomes exhibited a non-linear relationship. The probability of achieving a forgotten joint was the highest with preoperative HKAA > 172.0°, postoperative HKAA of 176.0-178.5°, and ΔHKAA < 5.5°.

CONCLUSION

To achieve the forgotten joint state, the ideal HKAA range after medial fixed-bearing UKA is 176.0-178.5° and ΔHKAA should be <5.5°. Patients with smaller preoperative aLDFA and HKAA have a lower probability of achieving a forgotten joint after UKA.

Racial and Socioeconomic Differences in Distance Traveled for Elective Hip Arthroplasty

Introduction:

There are data that disparities exist in access to total hip arthroplasty (THA). However, to date, no study has examined the relationship between distance traveled to undergo THA and patient demographic characteristics, such as race, insurance provider, and income level as well as postoperative outcomes.

Methods:

Data from the Healthcare Cost and Utilization Project, American Hospital Association, and the United States Postal Service were used to calculate the geographic distance between 211,806 patients' population-weighted zip code centroid points to the coordinates of the hospitals at which they underwent THA. We then used Healthcare Cost and Utilization Project data to examine the relationships between travel distance and both patient demographic indicators and postoperative outcomes after THA.

Results:

White patients traveled farther on average to undergo THA as compared with their non-White counterparts (17.38 vs 13.05 miles) (P < 0.0001). Patients with commercial insurance (17.19 miles) and Medicare (16.65 miles) traveled farther on average to receive care than did patients with Medicaid insurance coverage (14.00 miles) (P = 0.0001). Patients residing in zip codes in the top income quartile traveled farther to receive care (18.73 miles) as compared with those in the lowest income quartile (15.31 miles) (P < 0.0001). No clinically significant association was found between travel distance and adverse postoperative outcomes after THA.

Discussion:

Race, insurance provider, and zip code income quartile are associated with differences in the distance traveled to undergo THA. These findings may be indicative of underlying disparities in access to care across patient populations.

The Forgotten Joint Score patient-acceptable symptom state following primary total hip arthroplasty

AIMS

The Forgotten Joint Score-12 (FJS-12) is a validated patient-reported outcome measure (PROM) tool designed to assess artificial prosthesis awareness during daily activities following total hip arthroplasty (THA). The patient-acceptable symptom state (PASS) is the minimum cut-off value that corresponds to a patient's satisfactory state-of-health. Despite the validity and reliability of the FJS-12 having been previously demonstrated, the PASS has yet to be clearly defined. This study aims to define the PASS of the FJS-12 following primary THA.

METHODS

We retrospectively reviewed all patients who underwent primary elective THA from 2019 to 2020, and answered both the FJS-12 and the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) questionnaires one-year postoperatively. HOOS, JR score was used as the anchor to estimate the PASS of FJS-12. Two statistical methods were employed: the receiver operating characteristic (ROC) curve point, which maximized the Youden index; and 75th percentile of the cumulative percentage curve of patients who had the HOOS, JR score difference larger than the cut-off value.

RESULTS

This study included 780 patients. The mean one-year FJS-12 score was 65.42 (SD 28.59). The mean one-year HOOS, JR score was 82.70 (SD 16.57). A high positive correlation between FJS-12 and HOOS, JR was found (r = 0.74; p<0.001), making the HOOS, JR a valid external anchor. The threshold score of the FJS-12 that maximized the sensitivity and specificity for detecting a PASS was 66.68 (area under the curve = 0.8). The cut-off score value computed with the 75th percentile approach was 92.20.

CONCLUSION

The PASS threshold for the FJS-12 at one year following primary THA was 66.68 and 92.20 using the ROC curve and 75th percentile approaches, respectively. These values can be used to achieve consensus about meaningful postoperative improvement to maximize the utility of the FJS-12 to evaluate and counsel patients undergoing THA. Cite this article: Bone Jt Open 2022;3(4):307-313.

The influence of obesity on achievement of a 'forgotten joint' following total knee arthroplasty

INTRODUCTION

Obesity has been associated with poorer outcomes following total knee arthroplasty (TKA); however, data remain sparse on its impact on patients' joint awareness following surgery. This study aims to investigate the impact of body mass index (BMI) on improvement in outcomes following TKA as assessed by the Forgotten Joint Score-12 (FJS-12).

MATERIALS AND METHODS

We retrospectively reviewed 1075 patients who underwent primary TKA from 2017 to 2020 with available postoperative FJS-12 scores. Patients were stratified based on their BMI (kg/m²): < 30, 30.0-34.9 (obese class I), 35.0-39.9 (obese class II), and ≥ 40 (obese class III). FJS-12 and KOOS, JR scores were collected at various time points. Demographic differences were assessed with Chi-square and ANOVA tests. Mean scores between BMI groups were compared using univariate ANCOVA, controlling for observed demographic differences.

RESULTS

Of the 1075 patients included, there were 457 with a BMI < 30, 331 who were obese class I, 162 obese class II, and 125 obese class III. There were no statistical differences in FJS-12 scores between the BMI groups at 3 months (27.24 vs. 25.33 vs. 23.57 vs. 22.48; p = 0.99), 1 year (45.07 vs. 41.86 vs. 40.51 vs. 36.22; p = 0.92) and 2 years (51.31 vs. 52.86 vs. 46.17 vs. 44.97; p = 0.94). Preoperative KOOS, JR scores significantly differed between the various BMI categories (49.33 vs. 46.63 vs. 44.24 vs. 39.33; p < 0.01); however, 3-month (p = 0.20) and 1-year (p = 0.13) scores were not statistically significant. Mean improvement in FJS-12 scores from 3 months to 2 years was statistically greatest for obese class I patients and lowest for obese class III patients (24.07 vs. 27.53 vs. 22.60 vs. 22.49; p = 0.01). KOOS, JR score improvement from baseline to 1 year was statistically greatest for obese class III patients and lowest for non-obese patients (22.34 vs. 25.49 vs. 23.77 vs. 27.58; p < 0.01).

CONCLUSION

While all groups demonstrated postoperative improvement, those with higher BMI reported lower mean FJS-12 scores but these differences were not found to be significant. Our study showed no significant impact of BMI on postoperative joint awareness, which implies that obese patients, in all obesity classes, experience similar functional improvement following TKA.

LEVEL III EVIDENCE

Retrospective Cohort Study.

A Comparison of Clinical Outcomes and Implant Preference of Patients with Bilateral TKA: One Knee with a Patient-Specific and One Knee with an Off-the-Shelf Implant

BACKGROUND

The purpose of this retrospective study was to compare clinical outcome results, perceived function, and overall preference among patients who had undergone staged bilateral total knee arthroplasty (TKA) with a cruciate-retaining, customized implant (customized TKA, or C-TKA) in 1 knee and an off-the-shelf (OTS) implant in the contralateral knee.

METHODS

Forty-seven patients (94 knees) from a single study center who underwent C-TKA in 1 knee and had previously undergone TKA with an OTS implant in the contralateral knee were included in this study. As the primary outcome measures, the Knee injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS, JR) and the Forgotten Joint Score (FJS) were self-administered by the study subjects at a single follow-up time point. Additionally, a follow-up questionnaire to compare patients' perceived joint stability, knee mobility, perceived feeling of the replaced joint, pain levels, and overall preference between their knees was administered.

RESULTS

The average follow-up was 2.3 years (range, 0.7 to 3.8 years) for C-TKA and 6.7 years (range, 1.6 to 11.1 years) for the OTS TKA. Significantly higher KOOS, JR (82 versus 77; p = 0.03) and FJS (68 versus 58; p = 0.04) results were found with C-TKA. The evaluation of the follow-up questionnaire showed that more patients reported having "a little" or "a lot" less pain (49% versus 15%), better perceived mobility (45% versus 12%) and stability (36% versus 13%), and a more "normal" feeling of their knee (60% versus 10%) with the C-TKA implant compared with their OTS counterpart. When patients were asked to directly compare their knees, we found that 72.3% of the patients preferred the knee that received C-TKA over the contralateral OTS knee replacement, with 21.3% seeing no difference and 6.4% preferring the OTS knee replacement.

CONCLUSIONS

We believe that this is the first study to examine patient-reported outcomes of customized and OTS TKA implant designs in the same patient. We conclude that patients in this study cohort who underwent staged bilateral TKA with a C-TKA implant in 1 knee and an OTS prosthesis in the other knee reported better for their patient-specific knee replacement, with higher FJS and KOOS, JR values, and overall, preferred the C-TKA knee more often compared with the OTS knee replacement.

LEVEL OF EVIDENCE

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

Mid-term outcomes following transfemoral revision of total hip arthroplasty for Vancouver B2/B3 periprosthetic fractures

INTRODUCTION

Periprosthetic femoral fractures (PFF) are often the reason for revising total hip arthroplasty (RTHA). Converting these fractures into modified extended trochanteric osteotomy (mETO) facilitates stem revision. Modular revision stems are a common choice with good results. We present mid-term outcomes in patients undergoing RTHA for Vancouver B2/B3 PFF using a tapered, fluted modular stem with an mETO approach.

MATERIALS AND METHODS

A single-center analysis of patients with RTHA for Vancouver B2/B3 PFF using a single modular implant with mETO was performed (2007 - 2019). Clinical outcome (mobility, range of motion, function), radiological outcome (fracture healing, stem subsidence) and patient reported outcome measures (FJS-12, HHS, EQ-5D) were assessed.

RESULTS

Ninety-seven patients (mean age 78.1 years, BMI 25.8 kg/m², 85.6% B2-fractures) were included; 80 patients had complete clinical and radiological follow-ups. Normal unaided gait without limping was achieved in 38/80 patients. After one year fracture / mETO healing occurred in 74/80 patients; 5.3 years after surgery, the respective FJS-12, HHS and EQ-5D (available in 34 patients) averaged 81.3 ± 30.2, 71.4 ± 18.7 and 0.8 ± 0.2. We documented 7 in-hospital deaths, 18.8% postoperative complications and 13.8% revisions with stem revisions being most commonly for subsequent PFF or subsidence.

CONCLUSION

Good clinical and radiological outcomes and rather low complication and revision rates (18.8% and 13.8%) were achieved. FJS-12 showed excellent results in patients undergoing RTHA for Vancouver B2/B3 PFF using a cementless, dual modular titanium revision stem and an mETO approach. Joint awareness was thereby similar to previously reported primary THA results at 5.3 years follow-up.

No difference in PROMs between robotic-assisted CR versus PS total knee arthroplasty: a preliminary study

The purpose of this study was to determine if significant clinical differences exist in patient-reported outcome measures (PROMs) between PS and CR TKAs implanted using robotic-assisted technology. This was an IRB-approved retrospective study from an institutional database evaluating 214 knees in 190 patients. Inclusion criteria included: primary RA-TKA, age 22-89 at the time of surgery, preoperative coronal limb deformity within 15º of neutral alignment, and minimum 1-year follow-up. The PS cohort consisted of 103 patients with 107 RA-TKAs, whereas the CR cohort consisted of 87 patients with 107 RA-TKAs. Cohorts were compared on the basis of demographics and PROMs (KSS knee, KSS function, FJS-12, KOOS-JR, WOMAC, and 5-point satisfaction Likert scale) collected preoperatively and at 1-year follow-up. Statistical analyses comparing measures were conducted via Student's t tests for continuous data and Chi-squared analyses for categorical data. There were no significant differences identified in short-term PROMs at 1-year follow-up between cohorts (all p values > 0.05). 93.1% of patients with CR knees and 94.7% of patients with PS knees reported a satisfaction level of "very satisfied" or "satisfied". Revision arthroplasty occurred in six knees (2.8%, 3 knees in CR cohort, 3 knees in PS cohort) with no differences in overall complications between groups. The use of RA-TKA technology promoted high patient satisfaction scores within this study, independent of CR or PS implant type with no significant differences in PROMs, satisfaction, revisions, or complications between the two groups.

New-Onset Depression After Total Knee Arthroplasty: Consideration of the At-Risk Patient

BACKGROUND

Postoperative new-onset depression (NOD) has gained recent attention as a previously unrecognized complication which may put patients at risk for poor outcomes after elective total hip arthroplasty. We aimed to investigate risk factors for the development of NOD after total knee arthroplasty (TKA) and assess its association with postoperative complications.

METHODS

This is a retrospective, population-level investigation of elective TKA patients. Patients with a preoperative diagnosis of depression were excluded from this study. Two groups were compared: patients who were diagnosed with depression within one year after TKA (NOD) and those who did not (control). The association of both preoperative patient factors and postoperative surgical and medical complications with NOD was then determined using multivariate and univariate analyses.

RESULTS

Of 196,728 unique TKA patients in our cohort, 5351 (2.72%) were diagnosed with NOD within one year of TKA. Age <54 year old, female gender, preoperative anxiety disorder, drug, alcohol, and/or tobacco use, multiple comorbidities, and opioid use before TKA were all associated with a diagnosis of NOD postoperatively (all P < .001). Postoperative NOD was associated with periprosthetic fracture (OR 2.11; 95% CI 1.29-3.52; P = .033), aseptic failure (OR 1.61; 95% CI 1.24-2.07; P = .020), prosthetic joint infection (OR 1.55, 95% CI 1.30-1.85; P < .001), stroke (OR 1.24; 95% CI 1.09-1.42; P = .006), and venous thromboembolism (OR 1.24; 95% CI 1.12-1.37; P < .001).

CONCLUSION

Post-TKA NOD is common and is associated with poor outcomes. This may aid surgeons in developing both anticipatory measures and institute preventative measures for patients at risk for developing NOD.

Patients With High Chronic Postoperative Knee Pain 5 Years After Total Knee Replacement Demonstrate Low-grad Inflammation, Impairment of Function, and High Levels of Pain Catastrophizing

OBJECTIVES

Total knee replacement (TKR) normally provides improvements of physical function and reduces pain. However, ∼20% of the patients report chronic postoperative knee pain. The aims of the present study were to assess the pain, physical function, and physiological characteristics 5 years after TKR surgery.

MATERIALS AND METHODS

Eighty patients were recruited 5 years after TKR and divided into 2 groups based on their average 24-hour knee pain intensity assessed on a visual analog scale (VAS 0 to 10) ("high pain group": VAS≥3; "low pain group": VAS<3). The patients completed the PainDETECT Questionnaire (PDQ), Oxford Knee Score (OKS), Pain Catastrophizing Scale, and Forgotten Joint Score-12. Furthermore, the patients underwent a clinical examination of the knees and high-sensitivity serum C-reactive protein was measured as an inflammatory marker.

RESULTS

A total of 53% of the patients in the high pain group were not satisfied with the outcome, while only 11% of the patients in the low pain group was not satisfied, and the pain intensities in the 2 groups were 5.1 (4.6 to 5 to 6) and 1.1 (0.6 to 1.5) (P<0.001), respectively. Furthermore, the high pain group demonstrates worse scores in: Forgotten Joint Score-12 (P=0.001), OKS function (P<0.001), OKS pain (P<0.001), and Pain Catastrophizing Scale (P<0.001).The high pain group demonstrated increased level of high-sensitivity serum C-reactive protein (4.3 mg/L [3.2 to 5.5] vs. 1.7 mg/L [1.2 to 2.2], P<0.001), and decreased range of motion in the knee (110 vs. 119-degree range of motion, P=0.013).

DISCUSSION

Patients with high chronic postoperative knee pain 5 years after TKR demonstrate decreased physical function, higher levels of catastrophizing thoughts, and increased levels of inflammation.

Good Validity and High Internal Consistency of the Forgotten Joint Score-12 in Patients After Medial Opening Wedge High Tibial Osteotomy

BACKGROUND

The Forgotten Joint Score-12 (FJS-12) was originally developed to assess awareness of an artificial joint. Medial opening wedge high tibial osteotomy (MOWHTO), an alternative surgical method of knee replacement, is a joint-preservation surgery; therefore, joint awareness should be used to evaluate its clinical results. However, FJS-12 has not been validated as a tool to evaluate the postoperative results of MOWHTO. This study aimed to validate FJS-12 in MOWHTO.

METHODS

Patients with bilateral knee surgery, previous knee surgery, flexion contracture >15°, varus alignment >20°, and patients without plate removal surgery were excluded. Finally, 71 knees of 71 patients were analyzed, with a mean follow-up of 34.5 months. The FJS-12 score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were obtained, and the floor and ceiling effect of each score was investigated. Cronbach's α was calculated to determine the internal consistency of FJS-12. Spearman's correlation coefficients between FJS-12 and KOOS were calculated to assess convergent validity.

RESULTS

There were ceiling effects in 3 KOOS subscales (symptoms [25.4%], pain [15.5%], and activities of daily living [25.4%]) but not in FJS-12 (8.5%). No floor effect was noted in any patient-reported outcome measures. The total Cronbach's α was 0.9457 in FJS-12. FJS-12 showed moderate-to-strong positive correlations with all KOOS subscales (r = 0.64-0.72).

CONCLUSION

FJS-12 showed a lower ceiling effect than KOOS and high internal consistency and convergent validity in patients following MOWHTO. With its low ceiling effect, FJS-12 was found to be useful for evaluating patients following MOWHTO.

Vitamin E-enriched polyethylene bearings are not inferior to Arcom bearings in primary total knee arthroplasty at medium-term follow-up

INTRODUCTION

The release of wear particles can be responsible for periprosthetic osteolysis, which can in turn, lead to aseptic loosening. Vitamin E-infused polyethylene (HXLPE Vit-E) has been shown, in vitro, to be more resistant to wear than conventional polyethylene (UHMWPE) by its crosslinking (HXLPE) and its higher resistance to oxidation. After reading a case report of a fracture of a vitamin E-enriched HXLPE bearing, the aim of this retrospective study was to evaluate fracture risk and clinical inferiority or not of vitamin-E HXLPE compared to conventional polyethylene in total knee arthroplasty (TKA).

MATERIALS AND METHODS

Three hundred and forty-nine patients (403 TKAs) were contacted, to find out whether they had undergone revision surgery for any reason after a mean (SD) of 7 (1.5) years. Follow-up control radiographs were analyzed for periprosthetic radiolucent lines (RLL) and loosening. Two different Patient Reported Outcome Measurements Scores (PROMS), KOOS and FJS-12, were utilized to assess the daily functionality and identify potential problems.

RESULTS

No statistically significant difference in revision rate, occurrence of aseptic loosening or RLL nor outcome as measured with PROMS was observed.

CONCLUSIONS

No bearing fractures or clinical inferiority was observed for vitamin E-enriched HXLPE at medium-term follow-up (7 years) compared to conventional Arcom polyethylene.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The ceiling effects of patient reported outcome measures for total knee arthroplasty

BACKGROUND

Patient reported outcome measurements (PROMs) that exhibit a substantial ceiling effect show clustering of participant's scores towards the upper limit of a scale and consequently have low discriminatory power among high end scores. This study aimed to compare ceiling effects at 1 and 2 years postoperatively across commonly usedPROMs for TKA.

HYPOTHESIS

We hypothesized, that the analyzed PROMs differ substantially in regards to their ceiling effect.

PATIENTS AND METHODS

Patients that underwent a primary unilateral TKA and completed pre-operative and post-operative questionnaires were included in the analysis. Participants completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC and OKS preoperatively, and completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC,OKS and FJS postoperatively at 1 and 2 years.

RESULTS

1-year and 2-year follow-up data was available for 380 and 193 patients, respectively. The preoperative mean age was 68.0 (8.5) and mean BMI was 31.4kg/m² (6.6), with a male to female ratio of 49.6% to 50.4%. At 1 year postoperatively, a ceiling effect was seen for the Pain and ADL subscales of the KOOS and the KOOS JR. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a ceiling effect at 2 years postoperatively. We found 9.0% and 14.8% of patients achieving a maximum score in the FJS at 1 and 2 years, respectively, indicating the absence of a substantial ceiling effect.

CONCLUSION

The PROMs studied differ substantially with regards to their ceiling effect and consequently their ability to detect differences between well performing groups. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a substantial ceiling effect at 2 years postoperatively. We recommend using PROMs like the FJS and KOOS-12 with a more evenly distribution of scores across the scale when studying well performing cohorts.

LEVEL OF EVIDENCE

III.

Impact of Obesity on the Forgotten Joint Score Following Primary Total Hip Arthroplasty

BACKGROUND

Obesity is a growing public health concern. This study aims to identify the association of body mass index (BMI) on postoperative Forgotten Joint Score-12 (FJS-12) in patients undergoing primary total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 2130 patients at a single urban, academic, tertiary institution who underwent primary THA from 2016-2020 with available postoperative FJS-12 scores. Patients were stratified into two groups based on their BMI (kg/m²):<30 (nonobese) and ≥30 (obese). FJS-12 scores were collected postoperatively at 3 months, 1 year, and 2 years. Demographic differences were assessed with chi-square and independent sample t-tests. Mean scores between the groups were compared using multilinear regression analysis, controlling for demographic differences.

RESULTS

Of the 2130 patients included, 1378 were nonobese, and 752 were obese. Although obese patients reported lower FJS-12 scores all time periods, there were no statistical differences between the two groups at 3 months (53.61 vs 49.62;P = .689), 1 year (68.11 vs 62.45; P = .349), and 2 years (73.60 vs 65.58; P = .102). A subanalysis comparing patients who were of normal BMI (<25), overweight (25.0-29.9), and obese (≥30) followed a similar inverse trend in scores but showed no statistical differences at all postoperative time points (3m:P = .612,1y:P = .607,2y:P = .253). Mean improvement in FJS-12 scores from 3 months to 1 year (14.50 vs 12.83; P = .041), 1 year to 2 years (5.49 vs 3.13; P = .004), and from 3 months to 2 years (20.00 vs15.96; P < .001) were significantly greater for nonobese patients compared to obese patients.

CONCLUSION

While obesity trended toward lower FJS-12 scores, the differences in scores were not statistically significant compared to nonobese patients. BMI did not influence overall FJS-12 scores; however, obese patients achieved a slightly smaller statistical improvement during the first 2 years, though this may not be clinically significant.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Evaluation of joint awareness after acetabular fracture: Validation of the Forgotten Joint Score according to the COSMIN checklist protocol

BACKGROUND

A fracture of the acetabulum is an uncommon, but serious injury. Established outcome tools do not reflect the patient’s perspective after fracture of the hip joint. Originally designed for post-arthroplasty patients, the Forgotten Joint Score (FJS) is a patient-reported outcome measurement (PROM) tool evaluating the disease-specific health-related quality of life (HR-QoL).

AIM

To validate the FJS in patients after acetabular fracture.

METHODS

In a prospective mono-centric cohort study, we evaluated 100 patients at mean 5.2 ± 3.6 years after a fracture of the acetabulum. The validation study followed the complete COSMIN checklist protocol. For calculation of convergent validity, we used the Tegner-Activity Scale, the Western Ontario and McMaster Universities Osteoarthritis Index, the EuroQol-5D, and a subjective rating of change as an anchor variable.

RESULTS

We confirmed good internal consistency with a Cronbach‘s alpha of 0.95. With an intraclass correlation coefficient of 0.99 (95%CI: 0.97, 0.99), test-retest reliability of the FJS was excellent. Correlation coefficients between the questionnaires were moderate to high ranging from |0.56| to |0.83| (absolute value). No relevant floor or ceiling effects occurred. Standard error of measurement was 3.2 and smallest detectable change (SDC) was 8.8. Thus, changes greater than 8.8 points between two assessments denote a real change in FJS.

CONCLUSION

The FJS is a valid and reliable tool for evaluation of patient-reported outcome in posttraumatic condition after acetabular fracture. The SDC indicating a real clinical improvement was 8.8 points in the FJS. We could confirm responsiveness of the FJS and found no relevant floor- or ceiling effects.

Comparison of Joint Perception Between Posterior-Stabilized and Ultracongruent Total Knee Arthroplasty in the Same Patient

BACKGROUND

Posterior-stabilized and ultracongruent designs are 2 common examples of posterior cruciate ligament-substituting total knee arthroplasty (TKA) prostheses. There is a lack of evidence regarding joint perception differences between ultracongruent and posterior-stabilized TKA. The purpose of this study was to compare the postoperative knee stability, function, and joint perception between ultracongruent and posterior-stabilized TKA in the same patients in order to determine whether there was a difference based on design.

METHODS

This prospective, randomized controlled trial included 50 patients who underwent same-day bilateral TKA utilizing Persona (Zimmer Biomet) posterior-stabilized implants in 1 knee (posterior-stabilized group) and ultracongruent implants in the other knee (ultracongruent group). At 2 years postoperatively, patients were evaluated for knee stability, function, and joint perception. Postoperative static knee anteroposterior stability and femoral rollback were compared. Knee function was evaluated with use of the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Joint perception was compared by evaluating noise generation, side preference, satisfaction, and the Forgotten Joint Score.

RESULTS

The ultracongruent group had more knee anteroposterior laxity (4.5 mm compared with 1.8 mm in the posterior-stabilized group; p < 0.001) and less femoral rollback (4.2 mm compared with 9.0 mm in the posterior-stabilized group; p < 0.001). Knee Society Score and WOMAC scores were not significantly different between groups (all p > 0.05). Although the ultracongruent group showed less noise generation than the posterior-stabilized group (18% compared with 38%, respectively; p = 0.026), there were no differences in side preference, satisfaction, or Forgotten Joint Score (all p > 0.05).

CONCLUSIONS

Both groups had similar joint perception 2 years postoperatively, with obvious differences in noise generation and more sagittal laxity with less femoral rollback in the ultracongruent group.

LEVEL OF EVIDENCE

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

Patient-reported outcome measures (PROMs) following knee arthroplasty: a prospective cohort study protocol

INTRODUCTION

To evaluate the quality of clinical practice, patient-reported outcome measures (PROMs) are important as certain questions could only be answered by the patient himself. PROMs help to get a better understanding what is meaningful to a patient and directly affects daily functioning. To move beyond traditional measures, we are interested in what matters to patients and developed this project. The aim of this article is to provide the protocol for our study collecting PROMs in daily medical practice from patients who undergo knee arthroplasty.

METHODS AND ANALYSIS

This study is a single-site, observational, prospective cohort study. We will recruit patients scheduled for a knee arthroplasty in our medical office, situated in a private clinic. After signed informed consent, patients complete self-reported questionnaires before the surgery, after 4 months, 1 year, 2 years, 3 years, 4 years and 5 years. We will use the following PROMs: Knee injury and Osteoarthritis Outcome Score, Forgotten Joint Score, EuroQol five dimensions and satisfaction. Additionally, the surgeon will complete the objective Knee Society Score. Administration of the questionnaires will be electronically or paper-based. We will assess differences between preoperative and postoperative data with paired t-test for continuous variables and Wilcoxon signed-rank test for categorical variables. To assess subgroup differences, we will use unpaired t-test for continuous variables and Mann-Whitney U test for categorical variables. To assess possible presence of bias, we will conduct sensitivity analyses.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the local ethics committee in Basel, Switzerland. Written informed consent will be obtained from all patients. We will disseminate the results of the study through peer-reviewed journals, national and international conference presentations and presentations to relevant stakeholders through appropriate channels.

Patient-reported outcomes of 7133 distal femoral, patellar, and proximal tibial fracture patients: A national cross-sectional study with one-, three-, and five-year follow-up

BACKGROUND

Few studies have described patient-reported outcome measures (PROMs) in knee fracture patients. We reported knee-specific and generic median PROM scores after knee fracture and identified risk factors for poor outcome defined by low median PROM scores.

METHODS

In a Danish cross-sectional study of 7133 distal femoral, patellar, and proximal tibial fracture patients during 2011-2017, OKS, FJS-12, EQ5D-5L Index, and EQ5D-5L Visual Analogue Scale (VAS), were collected electronically (response rate 53%; median age 60; 63% female). Poor outcome was defined as score lower than median PROM score. Poor outcome risk factors were estimated as odds ratios from binary logistic regression models.

RESULTS

At 0 to one year after knee fracture, median PROM scores were 31 (OKS), 27 (FJS-12), 0.50 (EQ5D-5L Index), and 74 (EQ5D-5L VAS). At >5 years after knee fracture, median OKS score was 40, median FJS-12 score was 54, median EQ5D-5L Index was 0.76, and median EQ5D-5L VAS score was 80. Age > 40 years had higher odds for poor OKS and FJS-12 scores at short- and long-term follow-up after knee fracture. Comorbidity burden, distal femoral fracture, and treatment with external fixation and knee arthroplasty were risk factors for poor outcome at long-term follow-up, for all four PROMs.

CONCLUSIONS

Although knee fracture patients have relatively high knee function and quality of life, their ability to forget about the knee joint after knee fracture is compromised. We identified several important risk factors for poor outcome measured by PROMs at different follow-up periods following knee fracture, which will help direct future quality-improvement initiatives.

Forgotten Joint Score in THA: Comparing the Direct Anterior Approach to Posterior Approach

BACKGROUND

The direct anterior approach (DAA) in total hip arthroplasty (THA) has gained popularity because of potential decreased postoperative pain and quicker recovery after surgery in comparison to the posterior approach (PA). With a growing focus on patient-reported outcome (PRO) measurements after surgery, we sought to determine if one approach led to better PRO scores as determined by the Forgotten Joint Score-12 (FJS-12) questionnaire.

METHODS

A retrospective chart review of primary THAs between September 2016 and September 2019 at a single academic hospital was conducted. Demographic and clinical data in addition to FJS-12 scores were collected. Two groups were created based on THA approach. Frequency rates, means, and standard deviations were used to describe baseline patient characteristics. Differences in demographic data were accounted for using linear regression models.

RESULTS

A total of 1469 cases were identified, with 830 using the DAA and 639 the PA. Significant demographic differences were observed between the 2 groups. However, when controlling for this, there were no differences in FJS-12 scores between approaches at 1 and 1.75 years (P = .232 and P = .486, respectively). At 12 weeks, DAA patients had higher satisfaction (59.21 vs 46.8; P = .006). When controlling for surgeon case volume, no differences in FJS-12 were observed at any of the time points (P = .536, P = .452, and P = .967, respectively) CONCLUSION: DAA THA patients trended toward better PRO scores than their PA counterparts. However, when controlling for surgeon case volume, no differences were observed, which suggests that surgeon case volume and experience have an important effect on patient satisfaction and FJS-12 scores.

Translation and Validation of Forgotten Joint Score for Total Hip Arthroplasty for Indian Population

BACKGROUND

The ultimate success of a total hip replacement lies in patients forgetting about their artificial joints during routine activities. "Forgotten Joint Score (FJS)" is emerging as an important tool in assessing outcomes of total hip arthroplasty. There has been no version of this score available in commonly spoken vernaculars in India. This study aims to formulate and validate the Hindi version of FJS in Indian population.

METHODS

A total of 136 patients with a minimum follow-up of 6 months and a maximum follow-up of 18 months after total hip arthroplasty were asked to fill the translated and adapted version of FJS questionnaire, at two points of time 2 weeks apart. The Hindi version of FJS (I-FJS) was tested for reliability and responsiveness, floor and ceiling effect and validity against modified Harris Hip Score (mHHS). Construct validity was expressed as the Pearson correlation coefficient. Internal consistency was expressed as Cronbach's alpha and test-retest reliability as the intra-class correlation coefficient (ICC).

RESULTS

I-FJS showed excellent internal consistency with Cronbach's alpha of 0.88. Intra-class correlation coefficient (ICC) was 0.94. I-FJS showed good correlation with m-HHS (r = 0.8, p = 0.001). The standard error of measurement was 3.6 and the smallest detectable change was 9.97. There was no floor or ceiling effect observed with I-FJS. Data from this study were insufficient to establish adequate responsiveness of I-FJS.

CONCLUSION

I-FJS is a valid, reliable and reproducible score for hip function in post-THA patients. It is devoid of any floor or ceiling effect. Hindi version of FJS could be an effective tool for studying hip function in the Indian population.

Forgotten Joint Score for early outcome assessment after total knee arthroplasty: Is it really useful?

Background

Forgotten Joint Score (FJS) has become a popular tool for total knee arthroplasty (TKA), but almost all studies had assessment performed 1 year after surgery. There is a need for a sensitive tool for earlier outcome assessment. The aim of this study was to investigate the usefulness of FJS within the first year after TKA.

Methods

This was a cross-sectional study. Patients within the first year after primary TKA were recruited. FJS was translated into the local language with a cross-cultural adaptation and was validated by assessing the correlation with the Western Ontario and McMaster Universities Arthritis Index score (WOMAC). Ceiling and floor effects (highest or lowest 10% or 15%) of both scores were compared. Skewness of scores was assessed with a histogram.

Results

One hundred sixty-three subjects were recruited: 84 (51.5%) had evaluation at 3 months after the operation, 56 (34.4%) at 6 months, and 23 (14.1%) at 12 months. FJS had fewer patients at the highest 10% (10.7% vs. 16.1%, P = 0.046) or 15% (19.6% vs. 32.1%, P = 0.027) at 6 months and within the first year overall (6.7% vs. 13.5%, P <0.001; 14.1% vs. 22.7%, P <0.001). Also, it had more patients at the lowest 10% (16.7% vs. 0%, P <0.001) or 15% (21.4% vs. 0%, P <0.001) at 3 months, 6 months (10.7% vs. 0%, P <0.001), and overall (12.9% vs. 0%, P <0.001; 16.6% vs. 0%, P <0.001). The skewness was much less than WOMAC (0.09 vs. −0.56).

Conclusions

FJS has a low ceiling effect but a high floor effect in the first year after TKA. Such characteristics make it less useful for the general assessment of early patient report outcome after operation.

Global research status and trends of UKA for knee osteoarthritis: a bibliometric analysis

Objective

As an alternative of knee-protection surgery, unicompartmental knee arthroplasty has been widely used for the treatment of knee osteoarthritis and has achieved good clinical results. However, reports on its data and trend are scanty. This article reviewed current status and trend in the research of UKA, and compared different regions, organizations and authors in terms of their contributions to the field.

Methods

The literature on UKA ranging from 2009 to 2019 was searched in the “Web of Science” database, and the search results were visually presented by using Excel and VOS-viewer software packages, and the status quo and development trends of relevant studies were analyzed.

Results

A total of 1264 articles on UKA were identified, of which 330 were the larger studies conducted in the United States. The institution that published most papers was Oxford University, with a total of 109 papers published. MURRAY DW was the largest contributor in this field. The National Institutes of Health was the largest funding agencies of the UKA. Studies could be divided into six clusters in terms of prosthesis design, follow-up investigation, OA etiology, hip-knee association, joint replacement registration, and computer navigation. “Computer-aided navigation” and “gait analysis” promise to be future hot spots in the field of UKA research.

Conclusion

Global trend analysis suggests that UKA research is gradually deepening and the number of papers has been on the rise. The USA was the largest contributor to this field. More research effort should be directed to “Computer-aided navigation”and “gait analysis”, which might be the popular topics in the UKA field in not very distant future.

Determining the Validity, Reliability, and Utility of the Forgotten Joint Score: A Systematic Review

BACKGROUND

With improving patient outcome after total hip and total knee arthroplasty, patient-reported outcome measures (PROMs) have seen a parallel rise in average scores and ceiling effects. The Forgotten Joint Score (FJS) is a PROM that has been previously proposed to reduce this observed ceiling effect. However, the validity and reliability of the FJS has not been well analyzed.

METHODS

The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried using keywords pertinent to FJS, validity, reliability, measurement properties, and PROM. The methodological quality of measurement properties was evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist.

RESULTS

In total, 13 articles met the inclusion criteria and were included in this analysis. Internal consistency was consistently high (Cronbach alpha >0.9). Test-retest reliability was good or excellent (interclass correlation coefficient ≥0.8) in all studies. As for construct validity, all the articles reported a positive rating. Floor and ceiling effects overall were low (<15%). Conflicting results were found for responsiveness and measurement error.

CONCLUSION

There is a strong evidence of good construct validity and test-retest reliability regarding the FJS, with moderate evidence of good internal consistency. Ceiling and floor effects were very low, showing a very promising discriminatory power between patients with a good outcome and patients with an excellent outcome. Therefore, especially in patients expected to achieve high levels of function after total joint replacement, we highly recommend the use of FJS for the long-term assessment of their treatment.

The Forgotten Joint Score-12 as a valuable patient-reported outcome measure for patients after first-time patellar dislocation

BACKGROUND

The aim of this study is to assess joint awareness after first-time patellar dislocation using the Forgotten Joint Score-12 (FJS-12) and to compare performance of this measurement tool to acknowledged patient-reported outcome scores.

METHODS

A retrospective analysis of patients with confirmed first-time patellar dislocation was performed. Patients were assessed with the FJS-12, the Kujala and the WOMAC scores. Reference values for the FJS-12 were obtained from a matched healthy control group with no history of previous knee joint pathology. We calculated Cronbach's alpha, assessed the ceiling effect for all scores, and calculated the Spearman correlation coefficient between them RESULTS: Fifty-six patients (mean follow-up 8.2 years, range 1.6-14.1) with a mean age of 26.4 years were analysed. Compared with the age- and gender-matched control group, the patellar dislocation group showed significantly lower (worse) mean FJS-12 scores (88 vs. 71, P < 0.001). Inter-score correlation between the FJS-12 and the Kujala was high (r = 0.74) and significant (P < 0.001), as well as between FJS-12 and WOMAC (r = 0.81, P < 0.001). Cronbach's alpha of the FJS-12 was 0.92 (95% confidence interval 0.90-0.94). The FJS-12 showed less ceiling effect (16%) compared with the Kujala score (23%) and the WOMAC score (32%).

CONCLUSIONS

The concept of joint awareness has been successfully applied to a patient population after patellar dislocation. The FJS-12 showed less ceiling effect compared with the Kujala and the WOMAC scores, suggesting the score was able to capture subtle knee problems in patients after patellar dislocation.

The Forgotten Joint Score-12 in Swedish patients undergoing knee arthroplasty: a validation study with the Knee Injury and Osteoarthritis Outcome Score (KOOS) as comparator

Background and purpose - Having patients self-evaluate the outcome is an important part of the follow-up after knee arthroplasty. The Forgotten Joint Score-12 (FJS-12) introduced joint awareness as a new approach, suggested to be sensitive enough to differentiate well-functioning patients. This study evaluated the Swedish translation of the FJS-12 and investigated the validity, reliability, and interpretability in patients undergoing knee arthroplastyPatients and methods - We included 109 consecutive patients 1 year after primary knee arthroplasty to assess construct validity (Pearson's correlation coefficient, r), internal consistency (Cronbach's alpha [CA]), floor and ceiling effects, and score distribution. The Knee injury and Osteoarthritis Outcome Score (KOOS) was the comparator instrument for the analyses. Further, 31 patients preoperatively and 22 patients postoperatively were included to assess test-retest reliability (intraclass correlation coefficient [ICC]).Results - Construct validity was moderate to excellent (r = 0.62-0.84). The FJS-12 showed a high degree of internal consistency (CA = 0.96). The ICC was good preoperatively (0.76) and postoperatively (0.87). Ceiling effects were 2.8% in the FJS-12 and ranging between 0.9% and 10% in the KOOS.Interpretation - The Swedish translation of the FJS-12 showed good validity and reliability and can be used to assess outcome after knee arthroplasty. Moreover, the FJS-12 shows promising results in its ability to differentiate well-functioning patients. Future studies on unidimensionality, scale validity, interpretability, and responsiveness are needed for a more explicit analysis of the psychometric properties.

Perception of a Natural Joint After Total Knee Arthroplasty

BACKGROUND

Assessing patients' functional outcomes following total knee arthroplasty (TKA) with traditional scoring systems is limited by their ceiling effects. Patient's Joint Perception (PJP) question of the reconstructed joint is also of significant interest. Forgotten Joint Score (FJS) was created as a more discriminating option. The actual score constituting a "forgotten joint" has not yet been defined. The primary objective of this study is to compare the PJP and the FJS in TKA patients to determine the FJS score that corresponds to the patient's perception of a natural joint.

METHODS

One hundred TKAs were assessed at a mean of 40.6 months of follow-up using the PJP question, FJS, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Correlation between the 3 scores and their ceiling effects were analyzed.

RESULTS

With PJP question, 39% of the patients perceived a natural joint (FJS: 92.9; 95% confidence interval [CI], 89.4-96.4), 12% an artificial joint with no restriction (FJS: 79.5; 95% CI, 65.7-93.3), 36% an artificial joint with minor restrictions (FJS: 70.0; 95% CI, 63.2-76.9), and 13% had major restrictions (FJS: 47.3; 95% CI. 32.8-61.7). PJP has a high correlation with FJS and WOMAC (Spearman's rho, -0.705 and -0.680, respectively). FJS and WOMAC had a significant ceiling effect with both reaching the best possible score in >15%.

CONCLUSION

Patients perceiving their TKA as a natural knee based on PJP have a FJS ≥89. PJP has a good correlation with FJS and may be a shorter, simple, and acceptable alternative.

Translation, cross-cultural adaptation, and validation of the Italian language Forgotten Joint Score-12 (FJS-12) as an outcome measure for total knee arthroplasty in an Italian population

Background

With ever-increasing numbers of patients undergoing elective total knee arthroplasty (TKA) and as TKA is performed in increasingly younger patients, patient demands and expectations have also increased. With improved patient outcomes, new PROMs with heightened discriminatory power in well-performing patients are needed. The present study aimed to translate and validate the Italian version of the Forgotten Joint Score (FJS-12) as a tool for evaluating pre-operative through longitudinal post-operative outcomes in an Italian population.

Methods

In this prospective study, patients with unilateral osteoarthritis, undergoing TKA surgery between May 2015 and December 2017 were recruited to participate in the study. The FJS-12 and WOMAC were collected pre-operatively and at six and 12 months post-operatively. According to the COSMIN checklist, reliability, internal consistency, validity, responsiveness, effect size, and ceiling effects and floor effects were evaluated.

Results

One hundred twenty patients completed the study, 66 of which participated in the evaluation of test-retest reliability. Good test-retest reliability was found (ICC = 0.90). The FJS-12 also showed excellent internal consistency (Cronbach α = 0.81). Construct validity with the WOMAC, as a measure of the Pearson correlation coefficient, was moderate (r = 0.45 pre-operatively; r = 0.46 at 6 months and r = 0.42 at 12 months post-operatively). From six to 12 months, the change was slightly greater for the WOMAC than for the FJS-12 patients (effect size d = 0.94; d = 0.75, respectively). At 12-months follow-up, the ceiling effects reflecting the maximum score were 12% for the FJS-12 and 6% for the WOMAC; however, scores within 10% of the maximum score were comprised 30% of the FJS-12 scores and 59% for the WOMAC.

Conclusion

The Italian FJS-12 demonstrated strong measurement properties in terms of reliability, internal consistency, and construct validity in TKA patients. Furthermore, a more detailed look at ceiling effects shows a superior discriminatory capacity when compared to the WOMAC at 12-months follow-up, particularly in better-performing patients.

Trial registration

clinicaltrials.gov NCT03805490. Registered 18 January 2019 (retrospectively registered).

Can We Help Patients Forget Their Joint? Determining a Threshold for Successful Outcome for the Forgotten Joint Score

BACKGROUND

Clinically important thresholds improve interpretability of patient-reported outcomes. A threshold for a successful outcome does not exist for the Forgotten Joint Score (FJS). The purpose of this study is to determine a threshold score for the FJS, 1 and 2 years after total hip arthroplasty (THA).

METHODS

A retrospective analysis of 247 primary THA recipients between December 2012 and April 2017 was performed. A binary "successful treatment" was defined as achieving a composite criterion of pain, function, and satisfaction. Receiver operator characteristic analysis determined thresholds for successful outcome at 1 and 2 years postoperatively, subanalyzed by demographics. Results were validated by a 75th centile comparison. The ceiling effect of FJS was also assessed.

RESULTS

The average FJS was 70.06 ± 29.39 and 75.05 ± 28.73 at 1 and 2 years, respectively (P < .001). The proportion of patients meeting the composite criteria for success was 66.8% at 1 year and 76.5% at 2 years (P = .017). The receiver operator characteristic analysis for FJS at 1 and 2 years yielded excellent accuracy as defined by area under the curve (0.91 and 0.92, respectively). The threshold values were 73.96 and 69.79 at the respective time points. A mild ceiling effect was found with 16% and 23% of cases achieving a score of 100 at 1 and 2 years, respectively.

CONCLUSION

The FJS has excellent accuracy in demonstrating successful outcome following THA. The FJS threshold for success at 1 and 2 years postoperatively is 73.96 and 69.79, respectively. The higher rates of success at 2 years, along with a rise in the mean FJS, may indicate continued clinical improvement up to 2 years after THA.

Assessment of functional recovery after total hip and knee arthroplasty: An observational study of 95 patients

BACKGROUND

A significant proportion of patients experience functional limitations following total hip and knee arthroplasty (THA and TKA). The purpose of this study was to investigate prospectively the patient-reported and objectively assessed functional recovery following THA and TKA.

METHODS

Patients were recruited at a regional Danish hospital, using a prospective, observational hypothesis-generating cohort design. Primary outcome measures were performance-based function (30-s chair-stand test) and self-reported physical function measured by the Hip Disability and Osteoarthritis Outcome Score (HOOS) for those who had undergone THA, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) for those who had undergone TKA. In addition, patient expectations, the "forgotten joint" scale and pain catastrophizing were measured. Outcome measures were collected at baseline (preoperatively) and at follow-up (4 months postoperatively).

RESULTS

A total of 95 patients (59 who had undergone THA and 36 who had undergone TKA) were recruited. Performance-based function improved only slightly, with a mean difference of 2.9 (95% confidence interval [CI] 1.9, 4.0) for THAs and 1.6 (95% CI 0.4, 2.8) for TKAs. Self-reported physical function improved significantly, with a mean difference of 37.9 (95% CI 31.5, 44.3) for THAs and 28.6 (95% CI 22.7, 34.4) for TKAs. However, dividing the cohort into "improved" and "non-improved" groups based on changes in performance-based function, no clinically relevant predictors for poor performance-based outcome could be found.

CONCLUSIONS

Self-reported outcome measures improved significantly following THA and TKA, whereas performance-based function improved only slightly by the 4-month follow-up. The subgroup that did not improve in performance-based function still reported significant improvements in self-reported outcome measures, demonstrating the difficulty in predicting optimal rehabilitation strategies after THA and TKA.

Does Medial Patellofemoral Osteoarthritis Influence Outcome Scores and Risk of Revision After Fixed-bearing Unicompartmental Knee Arthroplasty?

BACKGROUND

Patellofemoral osteoarthritis (OA) and anterior knee pain sometimes are considered contraindications for unicompartmental knee arthroplasty (UKA). However, several studies have demonstrated excellent patient-reported outcome scores in patients with patellofemoral OA treated with medial mobile-bearing UKA. Because these studies assessed the outcome of mobile-bearing UKA only, we were interested to see whether that finding also applies to fixed-bearing medial UKA.

QUESTIONS/PURPOSES

(1) Does patellofemoral OA influence patient-reported outcome scores after medial fixed-bearing UKA? (2) Does untreated medial patellofemoral OA increase the revision rate after medial fixed-bearing UKA?

METHODS

Between 2008 and 2015, one surgeon performed 308 medial fixed-bearing UKAs of a single design. Of those, 80 (26%) had patellofemoral OA of at least moderate severity (ICRS III or IV), and 228 (74%) did not. During that period, the surgeon did not use patellofemoral OA as a contraindication to UKA. In all, 13 patients (10%) in the patellofemoral OA group were lost before 2-year minimum followup, and 20 (11%) in the control group (without patellofemoral OA) were lost; all other patients were available, seen in the last 5 years, and included in this retrospective study. Mean (± SD) followup in the patellofemoral OA group was 39 ± 25 months, and it was 41 ± 23 in the control group. There were 100 women and 120 men. Patients had a mean age ± SD of 65 ± 10 years and mean ± SD BMI of 29 ± 4.5 kg/m.The intraoperative status of the patellofemoral joint was assessed using the International Cartilage Repair Society (ICRS) classification. The primary study endpoint was the Forgotten Joint Score (FJS-12); we also compared scores on the Lonner PatelloFemoral Score (LPFS), Oxford Knee Score (OKS) and Short-Form 12 (SF-12). With the numbers available, we had 80% power to detect a difference of 12.3 points on the Forgotten Joint Score. A secondary endpoint was femoral or tibial component revision for any reason verified over the phone for each included patient.

RESULTS

With the numbers available, there was no difference in FJS-12 score between the UKA with patellofemoral OA group and the group without patellofemoral OA 71 ± 29 versus 77 ± 26, mean difference - 6; 95% CI, -16 to 4.5; p = 0.270). Likewise, with the numbers available, we saw no differences in LPFS, OKS and SF-12. There was no difference in survivorship from all-cause revision at 4 years between the patellofemoral OA group and the group without patellofemoral OA (98%; 95% CI, 85.8-99.7 versus 99.5%; 95% CI, 96.0-99.2%; p = 0.352).

CONCLUSIONS

Patients with medial osteoarthritis in this single-center study generally benefitted from medial fixed-bearing UKA with good-to-excellent outcomes scores at short term, whether or not medial patellofemoral wear is present.

LEVEL OF EVIDENCE

Level III, therapeutic study.

No difference in joint awareness after TKA: a matched-pair analysis of a classic implant and its evolutional design

PURPOSE

Total knee arthroplasty (TKA) designs continuously evolve with the aim of improving patient outcomes. The purpose of the current study was to compare clinical and patient-reported outcome (PRO) results of a new TKA implant to its predecessor. The hypothesis of this study was that joint awareness and range of motion (ROM) of the newer design would be better than the classic design.

METHODS

One hundred patients undergoing TKA using the newer design (Attune^®) were matched by age and gender to 200 patients with the classic design (LCS^®). All patients underwent computer-navigated (Vector Vision, Brain-Lab, Germany) primary TKA by the same surgeon using the same technique. Data (FJS-12, WOMAC and ROM) were collected preoperatively and at 12 months follow-up at our implant registry.

RESULTS

Compared to preoperative scores, FJS-12, WOMAC and ROM improved significantly at 12 months follow-up. In the Attune group, mean FJS-12 and WOMAC at follow-up were 67.6 (SD 27.8) and 14.8 (SD 14.9) respectively, compared to 70.8 (SD 33.8) and 15 (SD 17.9) in the LCS group. Mean postoperative ROM was similar in both groups (Attune 120°, range 90°-140°, SD 10.4 and LCS 120°, range 85°-140°, SD 10.3).

CONCLUSION

The newer TKA and the predecessor design achieved comparable joint awareness, WOMAC scores and ROM at 1-year follow-up. The benefits expected of the newer design could not be observed in early clinical and PROs. The clinical relevance of this study is that it questions the importance of implant design as the single most important factor for patient outcomes.

LEVEL OF EVIDENCE

III.

High relative reliability and responsiveness of the forgotten joint score-12 in patients with femoroacetabular impingement undergoing hip arthroscopic treatment. A prospective survey-based study

The forgotten joint score-12 (FJS-12) may be an advantageous questionnaire in young patients with high hip function and a low level of pain. We investigated the reliability and the responsiveness of the FJS-12 in patients with femoroacetabular impingement undergoing hip arthroscopic treatment. Fifty patients were included in the reliability study and 34 patients were included in the responsiveness study. Test-retest reliability was assessed with intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC). Responsiveness was assessed from testing correlations between the FJS-12 and the Copenhagen Hip and Groin Outcome Score (HAGOS) of the change score, effect size (ES) and standardized response mean (SRM). Floor and ceiling effect were defined as present if the number of patients obtaining the maximum (100) and minimum score (0) exceeded 15%. The relative reliability was high (ICC = 0.9, 95% CI: 0.8-0.9) and the absolute reliability was low (SEM = 11, MDC_individual = 32, MDC_group = 4.5). The responsiveness was high, and the change score was highly correlated with the subscale 'pain' from the HAGOS and moderately correlated with the subscale 'ADL'. Furthermore, the FJS-12 exceeded or equalled the HAGOS subscales in ES and SRM. Below 15% of the patients scored the maximum or minimum score. The FJS-12 has high reliability, high responsiveness to change and shows no floor or ceiling effect.

Rasch analysis of the Forgotten Joint Score in patients undergoing knee arthroplasty

PURPOSE

The purpose of this study was to test the hypothesis that the "Forgotten Joint Score" (FJS-12) is a unidimensional interval-level scale. Unidimensionality refers to measuring a single attribute, i.e., the single ability to forget the arthroplasty. If this property is not verified, the interpretation of the score can be confusing. Unidimensionality is an essential prerequisite of construct validity and required if FJS-12 response data are to be validly summated into a single score. Interval-level dimension is an essential prerequisite of the parametric statistics. Rasch analysis was used to test our study hypothesis.

METHODS

The FJS-12 questionnaire was validated in 248 unilateral knee arthroplasty patients. Successive analyses were used to select items with good psychometric qualities to constitute the new "FJS". The external validity was assessed with the KUJALA questionnaire.

RESULTS

Quantity of relevant items was greater than 50%. Of the 12 original items, nine showed disturbed thresholds, indicating that patients were unable to discriminate among the five levels for these items. The data set was reanalyzed using a four-level scale. The new analysis indicated that the internal consistency was good (r = 0.84). Three items did not fit with the model and they were removed. The nine items of the final scale defined a unidimensional and linear measure of the forgotten joint, and showed a continuous progression in their difficulty. The perception of difficulty was group-independent. The correlation coefficient was moderate between FJS and KUJALA score (r = 0.4).

CONCLUSIONS

This new and items reduced FJS can be used in clinical practice with good psychometric qualities. It provides a reliable tool to follow up patient's evolution and document changes related to knee arthroplasty. This valid FJS is needed in evaluating patients' assessment, one indicator of quality of care.

LEVEL OF EVIDENCE

III-Therapeutic.

Promising early outcomes of a novel anatomic knee system

PURPOSE

The primary aim of this study was to report the early clinical and radiographic outcomes of patients who have been treated with total knee arthroplasty (TKA) using the Persona knee system. The secondary aim was to compare patient-reported outcomes (PROs) of the Persona knee system to those of the NexGen implant.

METHODS

A registry-based study of a consecutive series of 112 patients (129 knees) treated with the Persona knee system from a single center was conducted. Preoperative, 1-year, and 2-year radiographs and PROs were analyzed. Postoperative radiographs were assessed for radiolucency and component positioning. Patients were monitored for postoperative complications and revision. Two-year PROs were compared to a 1:1 propensity score-matched cohort of patients treated with the NexGen knee system.

RESULTS

Ninety-five percent of knees were within literature-defined safe ranges of the anatomical tibiofemoral axis, tibial varus/valgus angle, femoral flexion/extension angle, and tibial slope. Radiolucency was observed in 0.9% and 1.3% of knees at one and 2 years, respectively. Two-year PRO values demonstrated clinically meaningful improvements from the preoperative values. The cumulative 2-year percent revision was 3.0% (95% confidence interval 1.9-3.8%); there were no revisions due to implant mechanical failure. Patients treated with the Persona knee system had higher KOOS symptom (p = 0.037) and KOOS QOL (p < 0.001) scores compared to patients with the NexGen knee system.

CONCLUSIONS

This knee design demonstrates excellent clinical outcomes, similar or better than the NexGen knee system, at early follow-up.

LEVEL OF EVIDENCE

III.

Joint Perception After Total Hip Arthroplasty and the Forgotten Joint

BACKGROUND

Assessing patients' functional outcomes following total hip arthroplasty with traditional scoring systems is limited by their ceiling effects. The Forgotten Joint Score (FJS) has been suggested as a more discriminating option. The actual score in the FJS which constitutes a "forgotten joint," however, has not been defined. The emerging concept of joint perception led to the development of the Patient's Joint Perception question (PJP) to assess the patient's opinion of their prosthetic joint.

METHODS

Two hundred fifty-seven total hip arthroplasties were assessed at a mean of 68 months of follow-up (range 57-79). Outcomes included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), FJS, and PJP. Correlation of the scores as well as the ceiling effects were analyzed.

RESULTS

The mean FJS was 88.5 (range 27.1-100). PJP was correlated with the FJS and WOMAC (Spearman's rho -0.510 and 0.465, respectively). Fifty-two percent of the patients felt their hip as a natural joint (FJS: 95% confidence interval [CI] 93.3-96.0), 24.1% as an artificial joint with no restriction (FJS: 95% CI 83.1-90.5), and 23.3% as an artificial joint with minor restrictions (FJS: 95% CI 73.8-82.2). Only 0.8% had major restrictions and none reported a non-functional joint. The ceiling effect was high with both the WOMAC and FJS, with 27.2% and 31.9%. In addition, 28.6% of the patients had a WOMAC >10 and 23.4% an FJS <90 while reporting having a natural hip. Furthermore, 21.5% with a perfect WOMAC or 21.9% with a perfect FJS reported having an artificial joint with or without limitation.

CONCLUSION

A forgotten hip perception corresponds to an FJS >93. In 20%-30% of the cases, the WOMAC and FJS failed to identify the forgotten joint, or reached the maximum score when the patients did not feel their hip was natural. The PJP is a simple and reliable tool that enables identification of patients who feel replaced hip is natural.

Minimal important change values for the Oxford Knee Score and the Forgotten Joint Score at 1 year after total knee replacement

Background and purpose - Interpreting changes in Oxford Knee Score (OKS) and Forgotten Joint Score (FJS) following total knee replacement (TKR) is challenged by the lack of methodologically rigorous methods to estimate minimal important change (MIC) values. We determined MIC values by predictive modeling for the OKS and FJS in patients undergoing primary TKR. Patients and methods - We conducted a prospective cohort study in patients undergoing TKR between January 2015 and July 2016. OKS and FJS were completed preoperatively and at 1 year postoperatively, accompanied by a 7-point anchor question ranging from "better, an important improvement" to "worse, an important worsening." MIC improvement values were defined with the predictive modeling approach based on logistic regression, with patients' decisions on important improvement as dependent variable and change in OKS/FJS as independent variable. Furthermore, the MICs were adjusted for high proportions of improved patients. Results - 333/496 (67.1%) patients with a median age of 69 years (61% female) had complete data for OKS, FJS, and anchor questions at 1 year postoperatively. 85% were importantly improved. Spearman's correlations between the anchor and the change score were 0.56 for OKS, and 0.61 for FJS. Adjusted predictive MIC values (95% CI) for improvement were 8 (6-9) for OKS and 14 (10-18) for FJS. Interpretation - The MIC value of 8 for OKS and 14 for FJS corresponds to minimal improvements that the average patient finds important and aids in our understanding of whether improvements after TKR are clinically relevant.

Robot-assisted total hip arthroplasty: Clinical outcomes and complication rate

BACKGROUND

The purpose of this study was to report minimum 2-year outcomes and complications for robotic-arm-assisted total hip arthroplasty (THA).

METHODS

Data were prospectively collected and retrospectively reviewed between June 2011 and April 2014. Inclusion criteria were primary robotic-arm-assisted THAs treating idiopathic osteoarthritis with ≥ 2-year follow-up. Demographics, operating time, complications, 2-year outcome scores and satisfaction, and subsequent surgeries were recorded.

RESULTS

There were 181 cases eligible for inclusion, of which 162 (89.5%) had minimum 2-year follow-up. At the latest follow-up, the mean visual analogue scale was 0.7, satisfaction was 9.3, Harris hip score was 91.1 and forgotten joint score was 83.1. Six (3.7%) intraoperative complications and six (3.7%) postoperative complications were reported. No leg length discrepancies (LLDs) or dislocations were reported.

CONCLUSIONS

Robotic-arm-assisted THA demonstrates favourable short-term outcomes and does not result in a higher complication rate compared to non-robotic THA as reported by the literature.

Normalized gait analysis parameters are closely related to patient-reported outcome measures after total knee arthroplasty

Up till now, only a weak connection could be shown between patient-related outcome measures (PROMs) and measurements obtained by gait analysis (e.g. speed, step length, cadence, ground reaction force, joint moments and ranges of motion) after total knee arthroplasty (TKA). This may result from the methodical problem that regression analyses are performed using data that are not normalized against a healthy population. It does appear reasonable to assume that patients presenting a physiological gait pattern are content with their joint. The more the gait parameters differ from a normal gait pattern the worse the clinical outcome measured by PROMs should be expected to be. In this retrospective study, 40 patients were enrolled who had received a gait analysis after TKA, and whose PROMs had been evaluated. A gender- and age-matched control group was formed out of a group of test persons who had already undergone gait analysis. Gait analysis was undertaken using the motion analysis system 3D Vicon with ten infrared cameras and three strength measuring force plates. The physiological gait analysis parameters were deduced from arithmetic mean values taken from all control patients. The deviances of the operated patients' gait analysis parameters from the arithmetic mean values were squared. From these values, the Pearson correlation coefficients for different PROMs were then calculated, and regression analyses were performed to elucidate the correlation between the different PROMs and gait parameters. In the regression analysis, the normalized cadence, relative gait speed of the non-operated side, and range of the relative knee moment of the operated side could be identified as factors which influence the Forgotten Joint Score (FJS-12). The explanation model showed an increase of the FJS-12 with minimisation of these normalized values corresponding to an approximation of the gait pattern seen in the healthy control group. The connection was strong, having a correlation coefficient of 0.708. A physiological gait pattern after TKA results in better PROMs, especially the FJS-12, than a non-physiological gait pattern does.

Joint awareness in posttraumatic osteoarthritis of the knee: validation of the forgotten joint score in long term condition after tibial plateau fracture

Background

Evaluating patient-reported outcomes (PRO) in early osteoarthritis (OA) of the knee is difficult. Established measurement tools are focused on one of the two major patient groups in knee surgery: young, highly active patients, or older patients with advanced degenerative OA of the knee. Joint awareness in everyday life is a crucial criterion in measuring PRO. The purpose of this study was to validate a German version of the “Forgotten Joint Score” (FJS) in patients after surgical treatment of tibial plateau fractures.

Methods

In this prospective cohort study, clinical and radiological outcomes data were collected from patients after surgical treatment of tibial plateau fractures following a skiing accident. Functional outcome questionnaires were administered including the FJS, the Lysholm-Score, the Tegner-Activity Scale (TAS), the EuroQol-5D (EQ 5-D), and a subjective rating of change. The validation study was carried out according to the COSMIN checklist protocol. The KLS was used to measure the presence and severity of OA on knee radiographs, and correlation with the FJS was measured.

Results

Cronbach‘s alpha was .96 (95%-CI .92, .99) confirming good internal consistency. Test-retest reliability of the FJS was high with an ICC₍₆₇₎ = .91 (95%-CI .85,.95). Furthermore, no relevant floor or ceiling effects were observed. FJS significantly differed in patients with different OA degrees (p = .041). Symptomatic patients had significant lower FJS than asymptomatic patients (p < .001).

Conclusions

This is the first study validating a disease-specific PRO, the FJS, in long-term outcomes after joint fracture. We demonstrated good psychometric properties and a significant correlation between the FJS and the radiologic degree of OA in patients with a history of tibial plateau fracture.

Trial registration

Clinical Trial Registry University of Regensburg Z-2015-0872-2. Registered 01. October 2015.

Birmingham Hip Resurfacing vs Total Hip Arthroplasty: A Matched-Pair Comparison of Clinical Outcomes

BACKGROUND

Birmingham hip resurfacing (BHR) has proven to be a good alternative for younger patients with osteoarthritis. Some have asserted that BHR may yield outcomes which are superior to total hip arthroplasty (THA), and that some studies which failed to show a difference were plagued by ceiling effects and lack of sensitivity of outcome measures. The purpose of this study is to compare outcomes of BHR and THA using the "Forgotten Joint" Score-12 (FJS), a more sensitive score with lesser vulnerability to the ceiling effect.

METHODS

Patients who underwent BHR were matched to patients who underwent posterior THA by computing a propensity score using 5 covariates: age, body mass index, gender, worker's compensation claims, and previous hip surgery. Surgical outcomes were assessed using 6 patient-reported outcome measures, including the FJS, the visual analog scale for pain, and patient satisfaction.

RESULTS

There were 42 patients in the BHR group and 18 patients in the THA group. The FJS was 78.0 for the BHR group and 76.0 for the THA group. The Veterans RAND 12-Item Health Survey Mental Component Summary and Short Form 12 Mental Component Summary were significantly higher in the BHR group. No differences were seen between all other patient-reported outcomes.

CONCLUSION

BHR offers excellent results in young patients that are comparable to THA. As no clinical difference could be shown between BHR and THA, even with the use of the FJS, the choice between BHR and THA should not be based solely on any expectation that either yields superior clinical outcomes compared to the other at short-term follow-up.

Joint awareness after ACL reconstruction: patient-reported outcomes measured with the Forgotten Joint Score-12

PURPOSE

To measure joint awareness in patients who have undergone anterior cruciate ligament (ACL) reconstruction and to investigate medium- and long-term results of the procedure.

METHODS

All patients who had undergone ACL reconstruction with the same arthroscopic surgical technique at our institution between 2011 and 2014 (medium-term follow-up group (Group I)) or between 2000 and 2005 (long-term follow-up group (Group II)) were considered for inclusion in the study. A group of healthy controls were recruited to obtain reference values for the FJS-12 (Forgotten Joint Score-12). Propensity score matching was applied to improve comparability of patients and healthy controls in terms of sex and age.

RESULTS

Fifty-eight patients of the Group I (mean follow-up 31.5 (SD13.4) months, range 12-54), 57 patients of the Group II (mean follow-up 139 (SD15.2) months, range 120-179), and the healthy control samples (100 individuals) were analysed. Significantly lower FJS-12 was found in both groups (Group I: 71.6 and Group II: 70.1), compared to the two matched control groups (88.1 and 90.0).

CONCLUSIONS

The concept of joint awareness was successfully applied to evaluate medium- and long-term results of ACL reconstruction. The clinical relevance of this study is that it extends the construct of joint awareness as a patient-reported outcome parameter to ACL reconstruction surgery.

LEVEL OF EVIDENCE

Level III.