Pseudoarthrosis after spinal fusion is an important complication leading to revision spine surgeries. Iliac Crest Bone Graft is considered the gold standard, but with limited availability and associated co-morbidities, spine surgeons often utilize alternative bone grafts.

Determine the non-inferiority of a novel submicron-sized needle-shaped surface biphasic calcium phosphate (BCP<µm) as compared to autograft in instrumented posterolateral spinal fusion.

Adult patients indicated for instrumented posterolateral spinal fusion of one to six levels from T10-S2 were enrolled at five participating centers. After instrumentation and preparation of the bone bed, the randomized allocation side of the graft type was disclosed. One side was grafted with 10cc of autograft per level containing a minimum of 50% iliac crest bone. The other side was grafted with 10cc of BCP<µm granules standalone (without autograft or bone marrow aspirate). In total, 71 levels were treated. Prospective follow-up included adverse events, Oswestry Disability Index (ODI), and a fine-cut Computerized Tomography (CT) at one year. Fusion was systematically scored as fused or not fused per level per side by two spine surgeons blinded for the procedure.

The first fifty patients enrolled are included in this analysis (mean age: 57 years; 60% female and 40% male). The diagnoses included deformity (56%), structural instability (28%), and instability from decompression (20%). The fusion rate determined by CT for BCP<μm was 76.1%, which compared favorably to the autograft fusion rate of 43.7%. Statistical analysis through binomial modeling showed that the odds of fusion of BCP<μm was 2.54 times higher than that of autograft. 14% of patients experienced a procedure or possible device-related severe adverse event and there were four reoperations. Oswestry Disability Index (ODI) score decreased from a mean of 46.0 (±15.0) to a mean of 31.7 (±16.9), and 52.4% of patients improved with at least 15-point decrease.

This data, aiming to determine non-inferiority of standalone BCP<μm as compared to autograft for posterior spinal fusions, is promising. Ongoing studies to increase the power of the statistics with more patients are forthcoming.

Introduction Modern metal-on-metal hip resurfacing (RHA) was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release.

Patients and methods 71 patients (< 65 yrs) were randomly assigned to receive either a RHA (n=38) or a conventional metal-on-metal (MoM) THA (n=33). Functional outcomes were assessed preoperatively, at 6, 12 and 24 months. Cobalt and chromium blood levels were analyzed preoperatively, at 3, 6, 12 and 24 months.

Results All functional outcome scores improved highly significant for both groups. At 12 and 24 months the UCLA Activity score was significantly higher for the RHA patients, the OHS only at 24 months. However, in spite of randomization UCLA scores also appeared to be higher in RHA patients at baseline. RHA patients were more satisfied at 12 months. Cobalt concentrations were significantly higher for RHA only at 3 and 6 months. Chromium levels remained significantly higher for RHA until 24 months. No pseudotumors were encountered in either group so far. One RHA was revised for early aseptic loosening and in two THA's a cup insert was exchanged for recurrent dislocation.

Conclusion RHA patients scored significantly higher on UCLA, OHS and satisfaction at some intervals, however, as for the UCLA preoperative levels were already in favor of RHA. Chromium blood levels were significantly higher for RHA, whereas for cobalt this was only observed up to 6 months. The true value of RHA against THA will be determined by longer follow-up and a possible shift of balance between their respective (dis)advantages.

Introduction

Total hip arthroplasty in young patients is still associated with high failure rates, especially at the acetabular side. Purpose of this study was to evaluate the long-term results of the Alloclassic cementless Zweymüller total hip prosthesis in patients younger than 50 years at the time of surgery.

Background: Unclear aetiology in scoliotic and kyphotic deformities of the spine are responsible for uncertainty in treatment options. To clarify aetiology a constant reference to what normal growth and optimal construction of the entire spine should be at the end of growth is lacking.

Examination of sitting children and consequent testing of muscular tightness can be useful in understanding the different disturbances of growth that keep the spine apparently away from an optimal configuration and thereby optimal function. Prolonged sitting of children exists only 200 years or less.

Goal:

- Better understanding of the role of the central nervous system, especially the cord and roots in proper and improper growth of the human spine.

Methods:

- Present obvious important and consistent clinical observations in children in sitting and supine position with early and advanced adolescent deformities, both kyphotic and scoliotic by photographic studies and video fragments.

Results: We discovered by alteration of our brace-configuration that applying lordotic forces exclusively on the thoracolumbar spine gives excellent correction of kyphotic and scoliotic deformities progressing in adolescence. In a study of 32 patients with double curves > 25° all scoliotic curves significantly (p< 0,001) reduced by correcting with a forced lordotic fulcrum.

Extended clinical examination of children with proven or suspected spinal deformities revealed a complex of consistent findings in different sitting positions and functional tests in supine and standing positions.

Discussion: By looking for scientific support for these phenomena in (bio-)mechanical literature the work of Milan Roth was disclosed in his complete width. His embryologic studies, (neuro) anatomical and radiological findings with their explanations, alongside interesting cadaver-, mechanical- and neuro-anatomical experiments and models can bring his concept of neuro-spinal relationship in growth and misgrowth back to orthopaedic daylight. Even Nicoladoni saw a century ago that a cascade of structural alterations take place around the “core”-unit of the spine: the boundaries of the central canal to let it stay on its place and in the shortest configuration possible in scoliosis, by suspected tensile and compressive forces.

Anatomical and biomechanical consequences of keeping the spine upright in standing, but more important in the sitting positions seems to fit. Children do sit for prolonged periods only in the last one or two centuries!

It can be shown that the presence of these tension related clinical signs are easily leading to high compressive forces with deformation of the ventral parts in the TL-junction while sitting In literature evidence of torsion facilitating anatomical features can be found to clarify why some spines deform in scoliosis an not in pure kyphosis

Conclusions: By recognising positive effects of creating lordosis at the thoracolumbar junction of the spine and consistent clinical findings in early deformations scientific support was found by early experimental work of Roth. With a leading role of the central nervous system in growth of the spine of standing and sitting vertebrates by steering a tension based system, deformation can be understood as adaptations. Consequences for preventive measures and therapeutic strategies in deformities seems inevitable.

Type I and II collagen-based scaffolds, with and without attached chondroitine sulphate (CS), were implanted without additional chondrocytes into full-thickness defects in the trochlea of young adult rabbits. We hypothesise that the chemical composition of the matrix will have a direct effect on the speed of repopulation and the phenotypic expression of the subchondral repair cells.

Evaluation of the repair process was performed with routine histology and with two quantitative histological grading systems, four and twelve weeks after implantation.

Four weeks after implantation, type I collagenous scaffolds were completely filled with a cartilage-like repair tissue. By contrast, type II collagenous scaffolds showed a superficial zone of cartilaginous tissue, and in many defects chondrocyte-like cells at the interface of the implant material with the subchondral bone. In collagen type II filled lesions larger areas of the scaffolds were completely devoid of repair tissue. Control defects showed a repair reaction that was very similar to that observed in defects filled with a type I scaffold.

After 12 weeks, the subchondral defect was largely replaced by bone and the differences between the scaffolds were less pronounced. The quantitative blind score of the sections confirmed that the scores of the control defect and of the collagen type I based scaffolds were slightly higher as compared to the type II based scaffolds. Irrespective of the type of scaffold, there was a trend that the scaffolds with CS scored slightly higher than those without CS.

We conclude that different types of scaffold induce different repair reactions. Collagen types I based scaffolds seem superior to guide progenitor cells from a subchondral origin into the defect. Repair cells in collagen type II based scaffolds seem to assume a chondrocyte-like phenotype, which could have a negative effect on the mobility of the repair cells.