A Simple Method for Measurement of Femoral Anteversion-Validation and Assessment of Reproducibility

Controlled rotation of long bones by guided growth: A proof of concept study of a novel plate in cadavers

Our novel plate design has been developed for controlled rotation of long bones by guided growth. The objective of this proof-of-concept study was to evaluate the precision of the rotation in the femur. Twelve cadaverous femora of six adults (right = 6, left = 6) underwent an osteotomy at the level of the physeal scar. The plates were inserted on each side of the distal femur. Growth was simulated by axial distraction of the bone segments. The femur was stabilized using a unilateral external fixator. Femoral torsion was assessed with computed tomography (CT) and with an electric goniometer before and after distraction. The obtained rotation was compared to the predicted rotation based on the dimension of the plate and the bone. All femora were rotated as intended. The mean obtained rotation was 26.3° (95% confidence interval [CI]: 23.5-29.0) and the mean predicted rotation was 28.2° (95% CI: 26.9-29.5) (p > 0.82). The mean axial distraction was 19.5 mm (95% CI: 17.7-21.3). The predicted rotation of the femora was similar to the obtained values on CT and by goniometer. The obtained rotation occurred as a result of an axial distraction of approximately 2 cm. This suggests a potential for controlled rotation of the femur based on the circumference of the bone and plate dimensions that occurs simultaneously with axial distraction. Clinical significance: These findings suggest a possible clinical application in the treatment of maltorsion in children by guided growth, where theplate design guides the bone into torsional axial growth correcting the deformity.

Analysis of Computed Tomography-Based Technique for Measuring Femoral Anteversion: Implications for Measuring Rotation After Femoral Intramedullary Nail Insertion

OBJECTIVES

To assess the reliability of the current computed tomography (CT)-based technique for determining femoral anteversion and quantify the prevalence and magnitude of side-to-side differences.

DESIGN

Cross-sectional cohort study.

SETTING

Academic trauma center.

PATIENTS

We reviewed CT scans from 120 patients with bilateral full-length axial cuts of both femurs. Two hundred forty femurs with no fractures or other identifying features in their femora were included. Ten unique data sets were created to measure anteversion of the left and right sides.

MAIN OUTCOME MEASUREMENTS

Intraobserver and interobserver reliability were calculated using intraclass correlation coefficients (ICCs) and pooled absolute differences. The mean absolute difference between the sides was determined using a fixed-effects model.

RESULTS

Interobserver reliability was high (ICC: 0.85, 95% confidence interval [CI]: 0.83-0.88). The pooled mean absolute magnitude of variation between reviewers was small at 1.6 degrees (95% CI: 1.4-1.8 degrees) per scan. The intraobserver reproducibility was high (ICC: 0.91, 95% CI: 0.88-0.93) with a mean error of 2.7 degrees (95% CI: 2.2-3.1 degrees) per repeat viewing of the same scan by the same person. The magnitude of side-to-side variation was 2.0 degrees (95% CI: 1.5-2.6 degrees). Twenty-one subjects (18%, 95% CI: 12%-25%) had a mean side-to-side calculated femoral anteversion difference of ≥10 degrees, whereas 6 (5%, 95% CI: 2-10) subjects had a calculated mean side-to-side difference of ≥15 degrees.

CONCLUSIONS

CT based femoral anteversion measurement techniques demonstrate good precision. Only 1 in 20 patients had side-to-side differences of 15 degrees or more.

CAPAbility: comparison of the JOURNEY II Bi-Cruciate Stabilised and GENESIS II total knee arthroplasty in performance and functional ability: protocol of a randomised controlled trial

Background

Osteoarthritis of the knee is a common condition that is expected to rise in the next two decades leading to an associated increase in total knee replacement (TKR) surgery. Although there is little debate regarding the safety and efficacy of modern TKR, up to 20% of patients report poor functional outcomes following surgery. This study will investigate the functional outcome of two TKRs; the JOURNEY II Bi-Cruciate Stabilised knee arthroplasty, a newer knee prosthesis designed to provide guided motion and improve knee kinematics by more closely approximating a normal knee, and the GENESIS II, a proven existing design.

Aim

To compare the change in Patient-reported Outcome Measures (PROMs) scores of the JOURNEY II BCS and the GENESIS II from pre-operation to 6 months post operation.

Methods

CAPAbility is a pragmatic, blinded, two-arm parallel, randomised controlled trial recruiting patients with primary osteoarthritis due to have unilateral TKR surgery across two UK hospitals. Eligible participants (n = 80) will be randomly allocated to receive either the JOURNEY II or the GENESIS II BCS knee prosthesis. Baseline measures will be taken prior to surgery. Patients will be followed at 1 week, 6 to 8 weeks and 6 months post-operatively. The primary outcome is the Oxford Knee Score (OKS) at 6 months post-operatively. Secondary outcomes include: other PROMs, biomechanical, radiological (computerised tomography, (CT)), clinical efficacy and safety outcomes. An embedded qualitative study will also investigate patients’ perspectives via interview pre and post surgery on variables known to affect the outcome of TKR surgery. A sub-sample (n = 30) will have additional in-depth interviews to explore the themes identified. The surgeons’ perspectives on the operation will be investigated by a group interview after all participants have undergone surgery.

Discussion

This trial will evaluate two generations of TKR using PROMS, kinematic and radiological analyses and qualitative outcomes from the patient perspective.

Trial registration

International Standard Randomised Controlled Trials Number Registration, ID: ISRCTN32315753. Registered on 12 December 2017.

Use of Inherent Anteversion of an Intramedullary Nail to Avoid Malrotation in Comminuted Femur Fractures: A Prospective Case- Control Study

OBJECTIVES

To (1) evaluate using the inherent anteversion of a second or third generation femoral nail to set the version of the femur during locked intramedullary nailing of comminuted femoral shaft fractures (Espinosa Technique [ET]) and compare it with our traditional method (traditional group [TG]) and (2) assess the variation of anteversion because of the inherent play in the nail itself.

DESIGN

A prospective IRB-approved study.

SETTING

Academic US Level 1 Trauma Center.

PATIENTS

Fifty-two consecutive patients with comminuted femur fractures all completed the study.

INTERVENTION

The first 27 patients had the anteversion determined using the patellar shadow and lesser trochanter (TG), and the next 25 patients were treated by ET.

MAIN OUTCOME MEASURE

Computed tomography scanogram for femoral anteversion and length in the normal versus operated femur.

RESULTS

A >15 degree difference from native to operated legs was found in 8/27 TG (29%, 95% CI 15.3%-54.2%), with a mean difference of 11.6 ± 10.2 degrees (95% CI 8.8-16.17) verses 1/25 in the ET group (2.5%, 95% CI 0%-15.3%), with a mean difference of 4.8 ± 6.2 degrees (95% CI 1.38-8.9) (P = 0.0068). There was a 5 degree variability in our ability to center the proximal locking screw in the femoral head and 5 degrees variation in distal locking.

CONCLUSIONS

The inherent anteversion of a second generation nail can be used to minimize malrotation of the femur after comminuted fractures during locked intramedullary nailing in patients with normal anteversion and is superior to our present fluoroscopic technique.

LEVEL OF EVIDENCE

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