Patient-reported outcome measures are a cornerstone of outcome assessment in orthopaedics. However, completing the pencil and paper questionnaires in clinic is something of a burden to the individual patient and the health care institution. We do not provide much in the way of incentives to collect PRO data. Lengthy questionnaires and hidden data analysis offer no direct benefit to the individual patient nor the clinician. Employing ePRO, utilising tablet PCs for questionnaire completion, can improve this situation considerably. Swift and cost-effective data management and instant availability of results using intuitive graphical display make questionnaire completion more rewarding. Direct feedback of PRO data during the consultation can inform the individual's care. Completing electronic questionnaires also makes computer-adaptive testing (CAT) possible. CAT creates dynamic questionnaires, adapting to the individual symptom burden of the individual patient. CAT both increases measurement precision and reduces the number of questions required. As such, ePRO assessment may help to maximise the efficiency and the utilisation of PRO data.

Aim

To investigate the validity of threshold values for the Oxford Hip and Knee Score (OHS and OKS) for treatment success 12 months after total knee or hip replacement.

Aim

To evaluate the association of BMI and improvement in patient-reported outcomes after TKA.

Aims

To validate the English language Forgotten Joint Score-12 (FJS-12) as a tool to evaluate the outcome of hip and knee arthroplasty in a United Kingdom population.

Obese patients undergoing total knee arthroplasty (TKA) face increased risks of complications such as joint infection and early revision. However, the influence of obesity on measures of patient function following TKA is poorly defined.

Knee arthroplasty outcome data for procedures carried out over an eight month period was extracted from a regional database in the UK. We analysed the impact of weight categories (BMI<30, BMI=30–34.9, and BMI≥35) on the Forgotten Joint Score – 12 (FJS-12) and Oxford Knee Score (OKS). Data was available preoperatively and 12 months postoperatively. Physical and mental health was assessed with the SF-12 one year after surgery.

Data from 256 patients were available. 49.6% had a BMI<30, 27.4% had a BMI 30–34.9 and 23.1% had a BMI≥35. Mean FJS-12 results at 1-year were 48.7 points for patients with a BMI<30, 40.7 points for patients with a BMI=30–34.9 and 34.0 points for patients with a BMI≥35. Effect sizes for change from baseline to 12-month post-op were 3.0 (Cohen's d) in patients with BMI<30 and d=2.2 in patients with BMI≥35. Mean OKS results at 1 year were 36.9 (BMI<30), 33.7 (BMI=30–34.9) and 32.0 (BMI≥35) respectively. Effect sizes for change from baseline to 12-month was d=2.1 (BMI<30) and d=1.9 (BMI≥35). Differences between BMI groups with regard to post-operative change were statistically significant for the FJS-12 (p=0.038) but not for the OKS (p=0.229).

This study highlights that outcome scores may differ in their ability to capture the impact of obesity on patient function following TKA. The FJS-12 showed significant differences in outcome based on patient obesity category, whereas the OKS did not detect between group differences.

Objectives

To assess the responsiveness and ceiling/floor effects of the Forgotten Joint Score -12 and to compare these with that of the more widely used Oxford Hip Score (OHS) in patients six and 12 months after primary total hip arthroplasty.

Objectives

The Oxford Hip and Knee Scores (OHS, OKS) have been demonstrated to vary according to age and gender, making it difficult to compare results in cohorts with different demographics. The aim of this paper was to calculate reference values for different patient groups and highlight the concept of normative reference data to contextualise an individual’s outcome.

Introduction

Periprosthetic femur fractures are a serious complication after hip replacement surgery. In an aging population these fractures are becoming more and more common. Open reduction and plate osteosynthesis is one of the available treatment options.

Since cementless stem fixation in hip arthroplasty is becoming more and more common, the overall incidence of intraoperative femoral fractures has risen considerably. Depending on primary or revision arthroplasty, literature reports fracture rates between a few percent up to one third of the cases.

In this study, methods commonly applied in the field of structural testing were customized for this specified interference fit situation. A cementless hip system (ABG II, Stryker) was used on animal bones and biomechanical bones.

Transient excitation in the form of regular hammer strokes and sinusoidal excitation using a shaker served as an input. The output of the system under test was measured on the greater trochanter using a piezoelectric accelerometer.

The signals were digitized with a high-speed data acquisition system and analyzed in real-time with spectrum analysis software.

Analysis included threshold detection in the time domain to determine the time delay between the input and output transducer. Spectrum analysis in the frequency domain included FFT analysis and frequency response function analysis to identify shifts of fundamental frequencies and harmonics to describe the vibrational changes with increasing stability.

A digital imaging system was set up to take pictures of the metal-bone site to measure inducible displacement with each hammer impact and correlate it with the vibrometry results. Furthermore a strain gauge circularly mounted around the proximal femur monitored accurately any hairline fracture.

This study shows that changes of the vibrational spectrum are directly related to implant fit. The range of interest is well in the sonic range, which apparently is the reason for many surgeons to listen and ‘feel’ carefully during advancing the broach or the final implant into the femur.

The study is trying to extract critical vibrational parameters correlated with stability and femoral integrity. Due to the different dimensions of the tested animal bones and lack of soft tissue damping, further experiments on cadavers need to be carried out.

Vibrational spectrum analysis could prove to be a useful tool to readily assess implant stability and femoral integrity. It seems to be most beneficial in revision surgery or minimally invasive hip replacement, where the risk of femoral fractures is increased or fissures could easily be missed.

Objective: To compare multi surgeon reliability of the classification systems of H. A. King and R.W. Coonrad and to analyse controversial classified curve patterns.

Design: Three scoliosis surgeons and one orthopedic fellow were presented the AP radiographs of seventy adolescent idiopathic scoliosis patients. All reviewers assigned a type to each curve according to the classification systems of H. A. King [1] and R. W. Coonrad [2].

Subjects: Interobserver agreement and intraobserver reproducibility were tested. Kappa coefficients were used to test reliability. Between the observers, the divergent assignments to curve patterns were analysed in quantitative as well as in qualitative terms. An error analysis was performed.

Results: For King’s classification, paired comparisons revealed a mean interobserver kappa coefficient of 0.45, and for Coonrad’s classification system 0.38, respectively. According to Svanholm et al., these values indicate poor reliability in terms of interobserver agreement. Error analyses for both classification systems revealed that the reason for poor reproducibility is disagreement on structural upper thoracic and structural lumbar curves among the observers.

Conclusion: Neither King’s nor Coonrad’s method appear to have sufficient interobserver reliabilty. In order to improve reliability we recommend unequivocal description of structural stigmata of upper thoracic and lumbar curves.

Objective: To evaluate the long term radiological and clinical outcome after posterior correction of adolescent right thoracic idiopathic scoliosis with Cotrel-Dubousset instrumentation (CDI) and Harrington rod instrumentation (HRI).

Design: Retrospective comparative analysis.

Subjects: Out of preoperative standing radiographs of 229 patients 30 pairs of female patients, one patient with Harrington rod instrumentation (HRI) and the other with Cotrel-Dubousset instrumentation (CDI), could be identified. Curves within pairs were comparable with regard to curve magnitude (thoracic and lumbar) and level of stable and neutral vertebrae. Follow up examination included a clinical review, long cassette upright PA and lateral radiographs of the spine and two patient outcome questionnaires. Mean follow up time for CDI patients was 128 months and for HRI patients 198 months respectively.

Outcome measures: The pain questionnaire according to Moskowitz [1] was used to assess back pain. A customized questionnaire was used to assess whether patients were satisfied with their postoperative cosmetic appearance.

Results: In 92 per cent of the patients L2 was the lowest instrumented vertebra. The thoracic Cobb angle in the HRI group was corrected from 64° to 42° (34%) and in the CDI group from 66° to 24° (58%). Group differences were significant (p=0.004). The lumbar Cobb angle in the HRI group was corrected from 41° to 24° (41%) and in the CDI group from 44° to 21° (52%) respectively. Group differences were significant (p=0.03). The lumbar lordosis below the fusion could be improved postoperatively in CDI patients (L2–L5: 31° to 37°), whereas it remained unchanged in HRI patients (L2–L5: 32°). Group differences were significant (p=0.005). The overall cosmetic appearance was better in the CDI group (CDI 76% excellent and good, HRI 71%, p=0.04).

15% of the CDI patients and 24% of the HRI patients reported frequent low back pain episodes. Group differences were significant (p=0.008). A high correlation between incidence of low back pain and low degrees of lumbar lordosis below the fusion was revealed in HRI patients (p=0.02).

Conclusion: With Cotrel-Dubousset instrumentation better correction of the thoracic and lumbar curves in the frontal plane and better restoration of the lumbar lordosis distal the fusion is achievable. The lack of restoration of lumbar lordosis below the fusion in HRI patients may have some impact on the higher incidence of low back pain episodes found in this group. The postoperative cosmetic result was better in patients with Cotrel-Dubousset instrumentation.