Introduction

Partial knee arthroplasty (PKA) has demonstrated the potential to improve patient satisfaction over total knee arthroplasty. It is however perceived as a more challenging procedure that requires precise adaptation to the complex mechanics of the knee. A recently developed PKA system aims to address these challenges by anatomical, compartment specific shapes and fine-tuned mechanical instrumentation. We investigated how closely this PKA system replicates the balance and kinematics of the intact knee.

INTRODUCTION

Trabecular Titanium is an open-cell regular structure composed by hexagonal cells of controlled pore, manufactured by Electron Beam Melting (EBM) technology, that allows moulding of cellular solid structures. The Lima Delta TT revision cups are One and Revision, which is characterized by a caudal hook and fins. Both allow internal modularity and cranial TT augments.

The aim of this prospective study is to evaluate the short to medium-term clinical and radiographic outcomes of acetabular revision cups in TT.

Summary:

Smaller increments in the antero-posterior dimensions of femoral components allows significant improvements in balancing of the knee after TKA with restoration of more normal soft-tissue stability.

Engineered bone tissue to recreate the continuity of damaged skeletal segments is one of the field of interest of tissue engineering. Trabecular titanium has very good mechanical properties and high in vitro and in vivo biocompatibility: it can be used in biomedical applications to promote osteointegration demonstrating that it can be successfully used for regenerative medicine in orthopaedic surgery (1). Purpose of this investigation was to evaluate the behavior of adipose tissue derived stem cells (hASCs) cultured on scaffolds of Trabecular TitaniumTM (Lima-Lto) (TT). hASCs are considered to be multipotent mesenchymal stem cells that are easily induced to differentiate into functional osteoblasts both in vitro and in vivo (2).

The hASCs were obtained from the subcutaneous adipose tissue of healthy donors during total hip replacement procedures after digestion with collagenase. They were seeded on monolayer and on the TT scaffolds, and incubated at 37 degrees C in 5% CO2 with osteogenic medium or control medium. The expression of bone-related genes using RT-PCR, time course of alkaline phosphatase activity and morphological investigation with Scanning Electron Microscopy (SEM) were performed to evaluate the osteogenic differentiation of hASCs. Alkaline phosphatase activity, marker of the differentiation toward the osteogenic pattern, was significantly higher in hASCs grown with osteogenic medium than in cells grown with control medium, both in monolayer and TT scaffolds; moreover, also alkaline phosphatase of hASCs grown on TT scaffolds in the presence of control medium increased with time, differently from that of cells grown on monolayer. The osteogenic differentiated hASCs expressed the bone-related genes type I collagen, osteocalcin, Runx-2 and alkaline phosphatase. SEM observations showed that hASCs differentiated toward osteoblast-like cells: they produced a big amount of extracellular matrix that covered the surface of the porous scaffolds with bridges between the pore walls. These data suggest that hASCs are able to adhere to TT scaffolds, to acquire an osteoblastic phenotype and to produce abundant extracellular matrix, with but also without osteogenic medium. We can therefore conclude that this material carries osteinductive properties being responsible of ostegenic differentiation; consequently, this scaffold/cells construct is effective to regenerate damaged tissue and to restore the function of bone tissue.

Since 1999 we have adopted the ceramic on ceramic bearing in total hip arthroplasty. We started with sandwich liners, abandoned afterwards in favor of all ceramic liners. We witnessed the progressive evolution of the diameters of the femoral heads from 28 mm to the actual 40 mm. Out of more than 500 implants, we experienced 1 case of fracture of the ceramics, 5 cases of squeaking and 5 dislocations. A total of 5 implants underwent revision.

Patients and Methods: In 1999 we started using a ceramic-ceramic bearing in THA with the SPH blind cup (Lima Lto, San Daniele del Friuli) that had a “sandwich” liner. The stem used was the F2L modular stem (Lima Lto.). In 2 years (1999–2000) we performed 32 total hip arthroplasties in 32 patients with these implants. From 2001 we started using an all-ceramic liner and two kind of stems: Modulus and C2 (Lima Lto). We performed from 2001 to 2003 76 total hip arthroplasties with these implants. From 1999 to 2003 the only diameter available for the heads was 28 mm. Starting from 2004, 32 and 36 mm heads were available. We implanted 391 ceramic-ceramic implants (23 28mm, 138 32mm and 230 36mm heads) using the Delta Cup (Lima Lto.). We’ve implanted 12 heads of 40 mm size. The stems used were the Modulus or the C2 stem.

We performed, from 1999, to March 2009 511 implants in 465 patients (46 bilateral). 320 patients were women, 145 men. Mean follow up is 5.3 years (6 months-10 years). Mean age was 68,4 years (18–80).

Results: The mean Harris Hip Score was 93,2 considering the overall population at last follow up (mean 5,3 years, range 6 months- 10 years). In 1 case we experienced the fracture of the liner. 5 implants had dislocations and 1 case needed revision. The other 4 implants were treated conservatively with excellent results at final follow up.

We had 5 cases of squeaking: in 1 case it recovered itself, in 2 cases the phenomenon is occasional and in 1 case it’s persistent. No revision surgery has been required by these 4 patients. 1 patient developed squeaking after a subdislocation and needed revision for substitution of the head.

We revised 3 other implants: 2 for infection and 1 for a periprosthetic fracture.

On the radiological side there were no signs of mobilization of the cup or of the stem.

We found radiolucent lines in 35 cases: 13 in zone 1 according to Gruen, 6 in zone 2 and 16 in zone 3. Radiolucent lines were always less than 2 mm wide and stable at all radiographic controls.

Discussion: The use of the ceramic-ceramic bearing in total hip replacement has become in the last years more and more widespread. This has been sustained by very strong data available in the literature about the results of these bearing surfaces at a long term follow up. Our experience shows excellent clinical and radiological results at a medium-long term follow up and are consistent with those published in the literature.

The skeleton is tuned for sensing and responding to mechanical forces: a global bone strain moves the extra-cellular fluid through the lacunocanalicular network of compact bone, so gene expression of osteocytes is mechanically modulated by extra cellular fluid flow shear stress. Several studies showed that shear stress modulates bone cells gene expression: in vitro mechanical stimulation impacts the levels of alkaline phosphatase, cAMP, intracellular calcium, NO, prostaglandin E2, c-fos, COX-2, osteopontin and osteocalcin. Aim of this study is to investigate the effect of shear stress on SAOS-2 human osteoblasts proliferation, bone matrix production and mineralization, using a biostable polyurethane as scaffold and a perfusion bioreactor.

Polyurethane scaffolds with an average porediameter of 624 micron were utilized. Scaffolds were sterilized and placed in to standard well-plates (condition A) and into a bioreactor with forced perfusion at a rate of 3 ml/min (condition B). Human osteosarcoma cell lineSAOS-2 was obtained from the ATCC and cultured in McCoy’s 5A modified medium. A suspension of 7′105 osteoblasts was added onto the top of each scaffold. Medium was changed every 3 days and sampled for osteopontin and-osteocalcin ELISA kits. After 16 days culture DNA and calcium contents were measured, light microscopy and SEM analysis were performed.

In condition B, in comparison to A, we observed 33% higher cells proliferation, 12.6-fold higher osteopontin secretion, 99.6-foldhigher osteocalcin secretion and 8-fold higher calcium deposition. Microscopy observations revealed that in condition A osteoblasts were few with thin discontinuous extracellular matrix; in contrast shear stress induced 3D modeling of cells and matrix organization, so several cells were in multilayer with highly developed matrix and no surfaces were cell free.

Statically cultured osteoblasts showed normal proliferation, but a very low matrix synthesis. Into bioreactor, which provides physiological levels of shear stress, the osteoblasts proliferated and showed increased metabolic activity.

Introduction In the past years a lot of interest has been raised on the mini-invasive surgical techniques in many fields of orthopaedic surgery.However,true innovative techniques have been rarely proposed,other then reducing the length of the incision with the aid of specially designed tools,particularly in the hip surgery.In the knee also, shorter scars should not be considered as the main purpose of the so called MIS(minimally invasive surgery)but as the side beneficial effect and the natural consequence of a more conservative technique,sparing soft tissues such as the quadriceps tendon,the extensor mechanism and the suprapatellar pouch,as well as nervous tissue and vascular supply.Considering this,the Mis-Quad Sparing technique is a really new technique,that has in view the object to preserve anatomic structures,and in particularly the extensor apparatus.

Patients and methods From june 2003 to june 2004 we’ve studied two homogeneous cohorts of patients uniform for age,gender,BMI and local and radiographic objectivity(Baseline characteristics have been compared between groups by means of Student T test or Fisher exact test)operated with the same implant(Zimmer, NexGen CR),one with QS technique(30 patients)and one with the standard approach(26 patients).

For the post-operative evaluation and for the critical comparison of the two groups we’ve considered the following parameters:length of operation,blood loss,ROM(at discharge,at 1 month,at 3 months,at 6 months),functional scores(using the Knee Society Assessment& Function Score),implants position and postoperative pain.In order to evaluate the differences among the two groups over time,we adopted a general linear model for repeated measures with calculation of Huber White robust standard errors to account for intra-patients correlation over time: a 2 sided p-value< 0.0125 was considered significant and Bonferroni correction was applied for post-hoc test.

Results and discussion The study has demonstrated that the Mis-QS technique allows less blood loss(p< 0.001 at all times considered),less pain (mean 10 points less with VAS),more rapid and better functional restoration (significant differences,p< 0.001,observed between groups and over time),with the same length of operation(at mean QS required only 10′ more than standard)and the same implant’s precision(p> 0.30 for all implant’s angles considered).Therefore,the supposed advantages of the QS technique can be considered real,based on our statistical comparison

Purpose To ascertain whether there are differences in the histopathological appearance of tendinopathic Achilles and patellar tendons.

Methods In males, we studied biopsies from tendinopathic Achilles (n = 28; average age 34.1 years) and patellar tendons (n = 28; average age 32.1), and Achilles tendons (n = 21; average age 61.8 years) from deceased patients with no known tendon pathology, and patellar tendons (n = 15; average age 28.3) from patients undergoing anterior cruciate ligament reconstruction. Haematoxylineosin stained slides were interpreted using a semi-quantitative grading scale (0: normal to 3: maximally abnormal) for fibre structure; fibre arrangement; rounding of the nuclei; regional variations in cellularity; increased vascularity; decreased collagen stainability; hyalinisation. All slides were assessed blindly twice, the agreement between two readings ranging from 0.170 to 0.750 (Kappa statistics).

Results The highest mean score of tendinopathic Achilles tendons was not significantly different from that of tendinopathic patellar tendons (11.6 ± 5 and 10.4 ± 3, respectively). The ability to differentiate between an Achilles tendon and a patellar tendon was low.

Conclusions Tendinopathic Achilles and patellar tendons show a similar histological picture. It was not possible to identify whether a specimen had been harvested from an Achilles or a patellar tendon on the basis of histological examination. The general pattern of degeneration was common to both tendinopathic Achilles and patellar tendons. A common, as yet unidentified, etio-pathological mechanism may have acted on both these tendon populations.

The use of conventional stems in hip arthroplasty may be difficult in cases of dysplasia, coxa vara or coxa valga, after fracture or proximal femur osteotomy. In fact the morphologic alterations of the proximal femur might require prosthetic components characterised by small size and different neck angles to restore correct joint biomechanics. In these cases we are often compelled to compromise between the ideal implant aneiversion and fit and what we can really achieve. An alternative to conventional prostheses is represented by custom-made prostheses.

For 3 years we have been using the Modulus stem in the treatment of morphologic disorders of the hip. The conic shape of the stem easily fits the different morphologies of the proximal femur, whereas the modularity of the neck makes it possible to correct length, inclination and declination of the femural neck. We studied 59 patients by clinical and radiographic examination before surgery and 1, 3, 6 and 12 months postoperatively. We recorded a statistically significant improvement in the clinical score already at 1 month but this was even better at 6 months after surgery, with respect to the pre-operative examination.

With the use of this prosthesis, the recovery of correct joint biomechanics together with high tribologic standards could improve the implant survival, leading to cost reduction and patient satisfaction.