1. Bones consist essentially of bundles of collagenous fibres united by a cementing substance in which the inorganic material lies in the form of minute plate-like crystals. 2. During weight bearing and muscle action bones as a whole are deformed to a variable extent. Periods of deformation are followed by periods of relaxed pressure during which the bones tend to return to their normal form. 3. These variations in deformation and elastic recoil set up alternating pressures and tensions within the bones along the bone cyrstal encrusted fibres which make up the trabeculae, lamellae and Haversian systems, and these alternating phases of compression and tension stimulate the activity of osteoblasts so that bone formation predominates over bone resorption. 4. These alterations of pressure and tension are intermittent and reciprocal in nature and do not, as postulated by the trajectorial theory, involve different trabeculae, nor is it necessary to consider whether tension or pressure is the more important phase in determining bone deposition. 5. The pressure exerted by cysts, tumours, erupting teeth, etc., is of a quite different nature, as is the response to trauma or callus formation in the healing of fractures. These processes are essentially vascular phenomena involving localised areas of bony tissue and not bones as mechanical units

Objectives

This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group.

1. The histories of 149 patients, coming to the Hospital for Sick Children within the first three years of life with congenital dislocation of the hip (191 dislocated hips), and treated by conservative methods, have been reviewed. 2. The patients with unilateral dislocations (107) have been divided into three groups, according to the angle of slope of the opposite acetabulum. This angle was measured on the first radiograph and related to the mean value for age and sex. 3. The opposite hip was classed as "normal" if the acetabular angle was below or within one standard deviation above the mean for sex and age; as "moderately shallow" if it was between one and two standard deviations above the mean; and as "shallow" if it was over two standard deviations above the mean. This grouping was found to have a direct bearing on the results of conservative treatment in unilateral cases. a) Those with "normal" opposite acetabula–accounting for most of the unilateral cases–responded well. b) Those with "moderately shallow" opposite acetabula responded variably. c) The group with "shallow" opposite acetabula usually failed to respond. 4. Most bilateral dislocations behaved as unilateral dislocations with shallow opposite hips. 5. Additional factors influencing the response to conservative treatment–sex, age at first attendance, family history, fragmentation of the femoral epiphysis and eccentric reduction–are discussed

1. Pain and pressure sensibility has been studied in the fibrous articular ligament and synovial membrane of the knee joint in normal human subjects and in patients subjected to arthrotomy under local anaesthesia. 2. The fibrous ligament was found to be a highly sensitive structure, containing many spots which give rise to sensations of pain or pressure when stimulated mechanically or chemically. Synovial membrane was found to be a relatively insensitive structure which only occasionally contains pain-sensitive spots. 3. Histological examination of articular capsule from the knee joints of normal and sympathectomised cats shows that articular ligaments have a rich nerve plexus and a variety of specialised and unspecialised nerve endings, most of which are somatic in origin. Synovial membrane contains a more delicate nerve network and also a variety of nerve endings, the majority of which are autonomic in origin. But a substantial number of somatic nerves enter the synovial membrane, some of which terminate in nerve loops, globular endings or simple unspecialised endings. 4. Histological examination of normal human articular capsule shows that its innervation closely resembles that of the cat, but no sympathectomised human material was examined. 5. The bearing of these findings on the symptomatology of joint disease is discussed briefly

Aims

We retrospectively report our experience of managing 30 patients with a primary malignant tumour of the distal tibia; 25 were treated by limb salvage surgery and five by amputation. We compared the clinical outcomes of following the use of different methods of reconstruction.

Aims

The aim of this large registry-based study was to compare mid-term survival rates of cemented femoral stems of different designs used in hemiarthroplasty for a fracture of the femoral neck.

Objectives

Opening wedge high tibial osteotomy (HTO) is an established surgical procedure for the treatment of early-stage knee arthritis. Other than infection, the majority of complications are related to mechanical factors – in particular, stimulation of healing at the osteotomy site. This study used finite element (FE) analysis to investigate the effect of plate design and bridging span on interfragmentary movement (IFM) and the influence of fracture healing on plate stress and potential failure.

1. Posterior fusion of the spine in scoliosis cannot be relied upon to maintain correction of the curve or to prevent progression of a vicious resistant curve. It can, however, hold to some extent the correction of a mobile curve and the compensation of a fixed curve. 2. Despite generally poor results as assessed radiographically, the clinical improvement is often gratifying. Most patients claim to be greatly improved: the spine feels stronger, there is less fatigue, and balance is better controlled. Moreover, visible deformity may be improved markedly even though the anatomical correction as observed radiographically is slight (Figs. l0 and 11). 3. It is believed that the true cause of relapse is that the bone formed from sliver grafts remains immature for a long time. Even when incorporated with the immature bone of the child's spine or the mature bone of the adult spine, it remains soft and resilient. When subjected to the stresses and strains of weight bearing and gravity, and then to the unnatural forces which initiated or perpetuated the scoliosis, this immature bone undergoes remodelling to Wolff's Law—like the neck of the femur after slipping of the upper femoral epiphysis. The forces that alter the grafted bone are not only lateral forces but also—perhaps more important—rotational forces. There seems to be a definite link between the degree of rotation and the amount of relapse, correction being maintained best when rotation is least

Aims

The primary aim of this study was to define and quantify three new measurements to indicate the position of the greater trochanter. Secondary aims were to define ‘functional antetorsion’ as it relates to abductor function in populations both with and without torsional abnormality.

Aims

Our aim in this study was to describe a continuing review of 11 total hip arthroplasties using 22.225 mm Alumina ceramic femoral heads on a Charnley flanged femoral component, articulating against a silane crosslinked polyethylene.

What is the present position? There is no doubt that the meaning of Kleinberg and Lieberman has been misconceived. With the passing of years their cautious conclusion concerning the acetabular index has been transformed into a firm conviction. Even so, it is apparent from the literature that the use of the acetabular index is a matter of controversy, and that, to a lesser degree, the normal values of the index are a matter of debate. It is concluded that the measurement is not an absolute index of a predisposition to congenital dislocation of the hip and cannot be divorced from other radiological signs. Nevertheless, so long as there is a feeling of uncertainty about the most reliable early signs of congenital dislocation of the hip, it would be folly to ignore a high acetabular index, especially in an infant over six months of age. It seems that to radiograph every infant at birth is not justified. The radiological signs at birth are not only unreliable because of problems of technique, but also equivocal because of the small size of the structures and the fact that they consist largely of cartilage. Until the radiographic technique is standardised it would be advisable to continue to regard 30 degrees as the upper limit of normal for the acetabular index in the newborn. To make recommendations concerning treatment is beyond the scope of this paper. Nevertheless it is worth stating that the presence of a high index alone is not necessarily regarded as an indication for immediate treatment. But an infant found to have a high acetabular index should be kept under close observation and should be thoroughly examined at regular intervals before the beginning of full weight bearing

Aims

Severe acetabular bone loss and pelvic discontinuity (PD) present particular challenges in revision total hip arthroplasty. To deal with such complex situations, cup-cage reconstruction has emerged as an option for treating this situation. We aimed to examine our success in using this technique for these anatomical problems.

We compared the peripheral blood and periprosthetic tissues of 53 patients at revision arthroplasty with those of 30 patients at primary arthroplasty to determine whether there is a systemic difference in lymphocytes in patients with worn hip implants. The absolute number and relative proportion of lymphocytes bearing CD2, CD3, CD4, CD8, CD16, CD19, HLA-DR, kappa and lambda antigens were compared with the levels of IL-1β, IL-6 and PGE. 2. in the pseudosynovial membrane as well as with a semiquantitative estimate of metal and polyethylene particles, necrosis and chronic inflammation and the total concentration of metals within the periprosthetic tissues. There was a significant increase in the relative proportion of CD2-positive T-cells and CD16-positive natural killer cells in the peripheral blood at revision arthroplasty compared with primary arthroplasty and an increased proportion of CD8-positive T-cells and a decreased ratio of CD4 to CD8 (helper inducer/suppressor cytotoxic cells). Three control patients, who went on to have revision surgery, had values at primary arthroplasty which were similar to those of patients at the time of revision surgery. These differences did not correlate with the local concentration of metal, plastic or cement or inflammatory response or the type of prosthesis. An inverse correlation was noted between the necrosis in the periprosthetic tissue and both the local production of IL-6 and the absolute numbers of T-cells in peripheral blood. We conclude that there may be several cell-mediated systemic immune responses to aseptic loosening, at least one of which may be directly related to events in the periprosthetic tissues. We cannot exclude the possibility that the changes in the proportion of CD8-positive cells reflected a predisposition, rather than a reaction, to loosening of the implant

Despite its intrinsic ability to regenerate form and function after injury, bone tissue can be challenged by a multitude of pathological conditions. While innovative approaches have helped to unravel the cascades of bone healing, this knowledge has so far not improved the clinical outcomes of bone defect treatment. Recent findings have allowed us to gain in-depth knowledge about the physiological conditions and biological principles of bone regeneration. Now it is time to transfer the lessons learned from bone healing to the challenging scenarios in defects and employ innovative technologies to enable biomaterial-based strategies for bone defect healing. This review aims to provide an overview on endogenous cascades of bone material formation and how these are transferred to new perspectives in biomaterial-driven approaches in bone regeneration.

Cite this article: T. Winkler, F. A. Sass, G. N. Duda, K. Schmidt-Bleek. A review of biomaterials in bone defect healing, remaining shortcomings and future opportunities for bone tissue engineering: The unsolved challenge. Bone Joint Res 2018;7:232–243. DOI: 10.1302/2046-3758.73.BJR-2017-0270.R1.

Lesions within the articular cartilage layer of synovial joints do not heal spontaneously. Some repair cells may appear, but their failure to become established may be related to problems of adhesion to proteoglycan-rich surfaces. We therefore investigated whether controlled enzymatic degradation of surface proteoglycan molecules to a depth of about 1 μm, using chondroitinase ABC, would improve coverage by repair cells. We created superficial lesions (1.0 × 0.2 × 5 mm) in the articular cartilage of mature rabbit knees and treated the surfaces with 1 U/ml of chondroitinase ABC for four minutes. The defects were studied by histomorphometry and electron microscopy at one, three and six months. At one month, untreated lesions were covered to a mean extent of 28% by repair cells; this was enhanced to a mean of 53% after enzyme treatment. By three months, the mean coverage of both control and chondroitinase-ABC-treated defects had diminished dramatically to 0.2% and 13%, respectively, but at six months both untreated and treated lesions had a similar coverage of about 30%, not significantly different from that achieved in untreated knees at one month. These findings suggest that, with time, chondrocytes near the surface of the defect may compensate for the loss of proteoglycans produced by enzyme treatment, thereby restoring the inhibitory properties of the matrix as regards cell adhesion. This supposition was confirmed by electron microscopy. Our results have an important bearing on attempts made to induce healing responses by transplanting chondrogenic cells or by applying growth factors