Introduction

There is no doubt that the future of limb lengthening lies with internal lengthening. Complication rates are reduced and patient satisfaction is increased. The evolution of internal lengthening peaked with the dual direction, easily inserted and externally controlled PRECICE Nail. It has excelled in performance in accuracy and satisfaction. Its versatility increased with smaller sizes and increased excursion. A field safety notice was issued was issued in October 2021 by the parent company NuVasive. The advice was monitoring of current cases and a hold on implantation until after a review of process. At the National Orthopaedic Hospital Cappagh we elected to remove all implanted nails and assess the nail integrity and physiological changes associated with implantation.

Introduction

Aneurysmal bone cysts commonly found in lower limbs are locally aggressive masses that can lead to bony erosion, instability and fractures. This has major implications in the lower limbs especially in paediatric patients, with potential growth disturbance and deformity. In this case series we describe radical aneurysmal bone cyst resection and lower limb reconstruction using cable transport and syndesmosis preservation.

Introduction

Hip arthrodiastasis for paediatric hip conditions such as Perthes disease is growing in popularity. Intended merits include halting the collapse of the femoral head and maintaining sphericity by minimising the joint reaction force. This can also be applied to protecting hip reconstruction following treatment of hip dysplasia. Our aim was to assess functional outcomes and complications in a cohort of paediatric patients.

The vast majority of total hip replacements (THR) implanted today enable modularity by means of a tapered junction; based on the Morse taper design introduced for cutting tools in the 19^th Century ¹. Morse-type tapers at the head-stem junction provide many benefits, key for a successful surgical outcome such as wider component selection and restoration of better biomechanics ². However, moving from mono-block to modular designs has not been without its issues. Fluid ingress and motion at the interface has led to a complex multifactorial degradation mechanism better known as fretting-corrosion ³. Fretting-corrosion products created at the junction are commonly associated with adverse local tissue reactions ⁴.

There is a wide variation in the taper junction of THR differing quite significantly from Morse's original design. Performance of the taper junction has been found to vary with different designs ^5,6. However, there is still a lack of common understanding of what design inputs makes a ‘good’ modular taper interface. The aim of this study was to better understand the links between implant design and fretting-corrosion initially focussing on the role of angular mismatch between male and female taper. A combination of experimental approaches with the aid of computational models to assist understanding has been adopted. A more descriptive understanding between taper design, engagement, motion and fretting-corrosion will be developed.

Three different sample designs were created to represent the maximum range of possible angular mismatches seen in clinically available THR modular tapers (Matched: 0.020 ±0.002 °, Proximal: 0.127 ±0.016 °, Distal: −0.090 ±0.002 °). Head-stem components were assembled at 2 kN. Motion and fretting-corrosion at the interface was simulated under incremental uniaxial sinusoidal loading between 0.5–4 kN at 8 intervals of 600 cycles. The different types of motions at the interface was measured using a developed inductance circuit composed of four sensing coils, digital inductance converter chip (LDC1614, Texas Instruments, US) and microcontroller (myRIO, National Instruments, US). Fretting-corrosion was measured using potentiostatic electrochemical techniques with an over potential of +100 mV vs OCP (Ivium, NL). Complimentary finite element (FE) models were created in Ansys (Ansys 19.2, US).

Under uniaxial loading, the ‘matched’ modular taper assemblies corroded most and allowed the greatest pistoning motion due to a seating action. ‘Distal’ and ‘proximal’ engaged modular tapers showed reduced corrosion and seating when compare to the ‘matched’ components. However the kinetics of corrosion and motion were interface dependent. It is hypothesized, and complimented by FEA analysis, that lower initial contact stress in the ‘matched’ modular tapers allows for greater subsidence and depassivation of the oxide layer and higher corrosion. ‘Matched’ modular tapers allowed less rotational and toggling motions compared to mismatched tapers, suggesting a reduced mismatch might perform better once the heads have seated over time. Future work involves tests conducted under a surgically relevant impaction force and physiological loading kinematics to develop this descriptive link between taper design, engagement and performance.

The study aimed to develop and assess a new classification system for Segmentation Defects of the Vertebrae (SDV), a frequent cause of congenital scoliosis. Existing nomenclature for the wide range of SDV phenotypes is inadequate and confusing eg ‘Jarcho-Levin syndrome’.

A multidisciplinary group of the International Consortium for Vertebral Anomalies and Scoliosis (ICVAS) met to formulate a new classification system, based primarily on radiology. SDV are identified by number affected, contiguity, and spinal region(s). The size, shape and symmetry of the thoracic cage, and rib number, symmetry and fusion are included, and familiar vertebral morphology terms retained, together with accepted syndrome names. The terms spondylocostal and spondylothoracic dysostosis apply only to phenotypes typified by the monogenic disorders due to mutated DLL3, MESP2, LNFG and HES7 genes.

Five ICVAS members (Group 1) then independently assessed 10 new cases, inter-observer reliability assessed using kappa. Seven independent radiologists (Group 2) then assessed the same cases before and after introduction to the new system. Inter-observer reliability for Group 1 yielded a kappa value of 0.21 (95% confidence intervals (CI) 0.052, 0.366, p=0.0046). For Group 2, before introduction to the new system, 1/70 responses (1.4%) agreed with the Group 1 consensus,12 different diagnoses were offered, and 38/70 (54.3%) responses were ‘Unknown’. After introduction to the new system 47/70 responses (67.1%; 95% CI 55.5, 77.0) agreed with Group 1 consensus, a 65.7% improvement (95% CI 52.5, 75.6, p< 0.00005). The system was well received by 6/7 radiologists.

The new system was found to be reliable and acceptable.

Ethics approval: None

Interest Statement: None

The anterolateral surgical exposure to the distal tibia for pilon fractures has become more popular. One of the potential benefits over the commonly used anteromedial approach is a reduction in wound complications due to the improved soft tissue coverage of the anterolateral tibia. Minimal data exists regarding the rate of complications with the anterolateral approach. The purpose of this study was to evaluate wound complications in the early postoperative period associated with the use of the anterolateral approach for pilon fractures.

Methods: A retrospective review was conducted to identify all operatively treated pilon fractures at our university level 1 trauma center from September 2005 through July 2007. Sixty-eight pilon fractures were identified. All patients were treated with a staged protocol utilizing immediate external fixation followed by delayed open reduction and internal fixation based upon the condition of the soft tissue envelope. Patients who had an anterolateral surgical approach were identified and their medical records were reviewed for the first six weeks postoperatively to determine the rate of wound complications. The endpoint of six weeks was chosen to identify complications related to the surgical exposure alone.

Results: Thirty-six of the sixty-eight patients with pilon fractures had an anterolateral surgical exposure. One additional patient had an anterolateral incision performed for revision of a previously treated pilon fracture. 97% of these fractures were AO/OTA 43-C (three C1, nine C2, and twenty-three C3). The median time delay to definitive fixation was 19 days (10–38 days). Sixteen (44.4%) of the fractures were open, ten of which were Gustilo type III (five IIIA, four IIIB, and one IIIC). Eight of the thirty-seven patients had wound complications related to the anterolateral incision within the first six weeks of definitive fixation. Six patients (16%) had minor complications which were successfully treated with dressing changes and oral antibiotics, and two (5%) had major complications, with evidence of deep wound infection that required formal irrigation and debridement.

Conclusion: In a case series with a high rate of complex open pilon fractures, open reduction and internal fixation utilizing an anterolateral approach provided good exposure of the distal tibia with a low incidence of early wound complications.

Significance: Pilon fractures, especially high energy complex open ones, have a high risk of wound complications. Avoiding complications is the key in managing high energy pilon fractures. This case series provides evidence that the anterolateral approach has a low rate of wound complications in the most complex pilon fractures.