1. The rates of vascularisation in 119 autogenous, homogenous and heterogenous bone grafts, placed in the femoral medullary cavity and under the renal capsule of rabbits, were studied. 2. Substantial differences have been found in the speed of vascular penetration and arrangement among autografts, homografts and heterografts : penetration of the heterogenous implant was six or more times slower. Moreover, large areas of the homografts and heterografts were often totally excluded from the circulation for as long as the research was continued (up to three months). Revascularisation of the cortical bone was slower and less profuse than in cancellous bone, keeping always the same respective proportion between the three types of bone we have described. The results on the kidney were much less constant, and I attribute this to the vascular peculiarities of the bed. 3. Vascular patterns peculiar to the time of implantation and type of graft are described. 4. Suggestive, even if not totally convincing, evidence was found of recanalisation of old vessels inside the graft by advancing vessels from the bed. 5. There is striking correlation between the rate of vascular penetration of the bone implants and their ultimate "take" or incorporation in the bed

1. Serial radiographs of fifty-two normal children's feet, taken at six-monthly intervals between two and five years, have been reviewed. 2. Twenty-one naviculars have been injected post-mortem and the vascularisation of the growing bone investigated. 3. The records of sixty-two children with a diagnosis of Köhler's disease have been studied. 4. It is submitted that abnormal ossification results from compression of the bony nucleus at a critical phase during growth of a navicular bone whose appearance is delayed. 5. Symptoms in Köhler's disease are related to further compression which produces vascular changes in the bony nucleus. Consequent ischaemia is followed by hyperaemia which produces local pain, tenderness and swelling. 6. Two radiographic types of Köhler's disease are described and attributed to variations in the basic vascular pattern of the affected bone. 7. The usual complete recovery of the navicular is ascribed in part to the basic arrangement of numerous radially penetrating vessels

The femoral head receives its blood supply primarily from the medial femoral circumflex artery, with its deep branch being the most important.

In a previous study, we performed classical anatomical dissections of 16 hips. We have extended our investigation with a radiological study, in which we aimed to visualise the arteries supplying the femoral head in healthy individuals. We analysed 55 CT angiographic images of the hip.

Using 64-row CT angiography, we identified three main arteries supplying the femoral head: the deep branch of the medial femoral circumflex artery and the posterior inferior nutrient artery originating from the medial femoral circumflex artery, and the piriformis branch of the inferior gluteal artery. CT angiography is a good method for visualisation of the arteries supplying the femoral head. The current radiological studies will provide information for further investigation of vascularity after traumatic dislocation of the hip, using CT angiography.

In this study the direct relationship between the type of bone implant used, the vascular reaction caused to the host and the revascularisation of the implant has been studied. It was found that the best graft was that which was the most rapidly and permanently vascularised. Not only was the biological affinity between the graft and the bed important, but the structural facilities offered by the implant for the "penetration" by the host vessels were also of paramount importance. Thus small, fresh, cancellous bone grafts offered the best chance of rapid incorporation provided they were not crushed to the point of making vascular progress difficult. The findings from this investigation so strongly suggest that the rapid revascularisation of the bone grafts was because of an end-to-end anastomosis of the vessels of the host with those in the implant that it seems justified to consider that the best bone graft is that which is richest in vessels. Apart from a recent short paper by Graf (1960), we have not found this assertion before. It is this which seems to make the fresh, autogenous, cancellous implant so superior to all others.

We believe that any new material for bone grafts should be tested by the technique described here. The material which one day may replace fresh, autogenous, cancellous implants will have to show the same readiness to vascular penetration, vascular osteogenesis and vascular permanency that at present is exhibited only by the cancellous autograft.

We performed a series of 16 anatomical dissections on Caucasian cadaver material to determine the surgical anatomy of the medial femoral circumflex artery (MFCA) and its anastomoses. These confirmed that the femoral head receives its blood supply primarily from the MFCA via a group of posterior superior nutrient arteries and the posterior inferior nutrient artery. In terms of anastomoses that may also contribute to the blood supply, the anastomosis with the inferior gluteal artery, via the piriformis branch, is the most important. These dissections provide a base of knowledge for further radiological studies on the vascularity of the normal femoral head and its vascularity after dislocation of the hip.

Objectives. An experimental piglet model induces avascular necrosis (AVN) and deformation of the femoral head but its secondary effects on the developing acetabulum have not been studied. The aim of this study was to assess the development of secondary acetabular deformation following femoral head ischemia. Methods. Intracapsular circumferential ligation at the base of the femoral neck and sectioning of the ligamentum teres were performed in three week old piglets. MRI was then used for qualitative and quantitative studies of the acetabula in operated and non-operated hips in eight piglets from 48 hours to eight weeks post-surgery. Specimen photographs and histological sections of the acetabula were done at the end of the study. . Results. The operated-side acetabula were wider, shallower and misshapen, with flattened labral edges. At eight weeks, increased acetabular cartilage thickness characterised the operated sides compared with non-operated sides (p < 0.001, ANOVA). The mean acetabular width on the operated side was increased (p = 0.015) while acetabular depth was decreased anteriorly (p = 0.007) and posteriorly (p = 0.44). The cartilage was thicker, with delayed acetabular bone formation, and showed increased vascularisation with fibrosis laterally and focal degenerative changes involving chondrocyte hypocellularity, chondrocyte cloning, peripheral pannus formation and surface fibrillation. . Conclusions. We demonstrate that femoral head AVN in the young growing piglet also induced, and was coupled with, secondary malformation in acetabular shape affecting both articular and adjacent pelvic cartilage structure, and acetabular bone. The femoral head model inducing AVN can also be applied to studies of acetabular maldevelopment, which is less well understood in terms of developing hip malformation. Cite this article: Bone Joint Res 2014;3:130–8

The re-establishment of vascularity is an early event in fracture healing; upregulation of angiogenesis may therefore promote the formation of bone. We have investigated the capacity of vascular endothelial growth factor (VEGF) to stimulate the formation of bone in an experimental atrophic nonunion model. Three groups of eight rabbits underwent a standard nonunion operation. This was followed by interfragmentary deposition of 100 μg VEGF, carrier alone or autograft. After seven weeks, torsional failure tests and callus size confirmed that VEGF-treated osteotomies had united whereas the carrier-treated osteotomies failed to unite. The biomechanical properties of the groups treated with VEGF and autograft were identical. There was no difference in bone blood flow. We considered that VEGF stimulated the formation of competent bone in an environment deprived of its normal vascularisation and osteoprogenitor cell supply. It could be used to enhance the healing of fractures predisposed to nonunion

Specific antisera to collagen Types I, II and III and proteoglycan were used to investigate the distributions of these molecules in normal human intervertebral discs. Immunofluorescent staining indicated the presence of small amounts of Type III collagen located pericellularly in normal adult intervertebral discs. This finding had not been demonstrated previously by other methods. Similar specimens of intervertebral discs from 17 patients with scoliosis of varying aetiologies were examined, but no evidence was obtained for primary connective tissue defects. Secondary changes, especially marked vascularisation of the inner annulus, were apparent in a number of scoliotic discs, and some of these showed enhanced staining for collagen Type I and proteoglycan, and intercellular matrix staining for Type III collagen

1. Twenty-five lower limbs, amputated above the knee for senile atherosclerosis with peripheral gangrene, have been investigated radiologically and histologically to determine the vascular patterns in ischaemic bone with particular reference to the tibia. These have been contrasted with the patterns found in non-atherosclerotic tubular bone. 2. The principal changes are the development of a diffuse vascularisation of compact and spongy bone; a widening of Haversian spaces which come to contain a variable number of sinusoidal blood vessels; and an increasing periosteal participation in cortical nutrition which is related to the severity and chronicity of the ischaemic process. 3. Views on the normal blood supply of long bones are discussed, and evidence is presented for regarding this as discrete and end-arterial in nature; in particular it is suggested that the normal cortex has a wholly medullary, centrifugal, arterial supply

1. Certain macroscopical and microscopical features of the tendo calcaneus of the rabbit are described and illustrated, and the vascularisation as revealed by Spalteholz clearing is presented. 2. The vessels of the epitenon are chiefly derived from proximal and distal sources. 3. The vessels of the paratenon are derived from the main arteries of the leg. 4. The two vascular systems are largely independent of each other except along one edge of the tendon by way of a mesotenon. 5. The paratenon, epitenon and mesotenon and the related vessels are comparable to those found in tendons with synovial sheaths. By inference and from evidence obtained by dissection on the living human subject it is suggested that the arrangements are similar in the human tendo calcaneus. 6. Considerable friction develops on movement between the surfaces of the paratenon and epitenon. This might be significant in pathological states of the human tendon

Specimens of femoral heads were studied at necropsy in two cases of Legg-Calve-Perthes' disease. One was that of a boy aged four years ten months who died from appendicitis; the other was from a boy aged six years who died from a malignant glioma. Both had been treated for one and a half years for Legg-Calve-Perthes' disease which was in a stage of repair at the time of death. The diseased femoral heads were moderately flattened but the surface cartilage was intact. Epiphysial bone and bone marrow were partly replaced by cartilage, fibrous tissue and granulation tissue, and new bone was being formed. Inflammatory reaction was inconspicuous. Enchondral bone formation was only slightly decreased, and the structure of the growth plate was undisturbed. There was no sign of systemic bone disease. In the first case the changes indicated that more than one episode of ischaemia had occurred, and an occlusion--probably from an old thrombus--was demonstrated in the posterior inferior retinacular artery of the femoral head. The last episode of ischaemia, furthermore, had caused infarction of part of the metaphysial bone. In both cases, the central area of the metaphysial bone of the affected femur contained fat, but there were few haemopoietic cells and it therefore looked pale. The findings are discussed in relation to previous work on the pathology in Legg-Calve-Perthes' disease, recent information on the vascularisation of the femoral head in children, and experimental and comparative animal studies

Our aim was to examine the potential of autologous perichondral tissue to form a meniscal replacement. In 18 mature sheep we performed a complete medial meniscectomy. The animals were then divided into two groups: 12 had a meniscal replacement using strips of autologous perichondral tissue explanted from the lower rib (group G) and six (group C) served as a control group without a meniscal replacement. In all animals restriction from weight-bearing was achieved by means of transection and partial resection of tendo Achillis. Six animals (four from group G and two from group C) were each killed at 3, 6 and 12 months. The grafts and the underlying articular cartilage were removed and studied by gross macroscopic examination, light microscopy, SEM, polarised light examination, and by biomechanical tests. In all the transplanted animals a new perichondral meniscus developed. After three months the transplants resembled normal menisci in size and thickness, while in the control animals only small rims of spontaneously grown tissue were seen. Microscopically, the perichondral menisci showed a normal orientation of collagen fibres and normal cellular characteristics, but in the central region, areas of calcification disturbed the regular tissue differentiation. Healing tissue in control animals lacked the normal fibre orientation and cellularity. SEM of perichondral menisci showed surface characteristics similar to those of normal sheep menisci without fissures and lacerations; the control specimens had these defects. The femoral and tibial cartilage in contact with the new menisci had normal surface characteristics apart from one animal with slight surface irregularities. Control animals showed superficial lesions after three months which increased at six to 12 months postoperatively. Microangiography of the newly grown tissue demonstrated a less intense vascularisation after three months when compared with normal menisci. The failure stress and tensile modulus of perichondral menisci were significantly lower than those of normal contralateral menisci, and spontaneously regenerated tissue in meniscectomised animals had even lower values. There were no significant differences in values between newly grown perichondral menisci and spontaneously grown tissue

The October 2015 Shoulder & Elbow Roundup³⁶⁰ looks at: Culture time important in propionibacterium acnes; Microvascularisation of the cuff footprint; Degenerative cuff tears: evidence for repair; Middle ground in distal humeral fractures?; Haste needed in elbow heterotopic ossification; Iatrogenic frozen shoulder; Salvage of failed humeral fixation

The April 2014 Shoulder & Elbow Roundup³⁶⁰ looks at: arthroscopic capsular release successful after six months; MCIC in cuff surgery; analgesia following arthroscopic cuff repair; platelet-rich fibrin; and cuff tear and suprascapular nerve neuropathy?

The February 2014 Shoulder & Elbow Roundup³⁶⁰ looks at: whether arthroscopic acromioplasty is a cost-effective intervention; shockwave therapy in cuff tear; whether microfracture relieves short-term pain in cuff repair; the promising early results from L-PRF augmented cuff repairs; rehabilitation following cuff repair; supination strength following biceps tendon rupture; whether longer is better in humeral components; fatty degeneration in a rodent model; and the controversial acromioclavicular joint dislocation.

This article presents a unified clinical theory that links established facts about the physiology of bone and homeostasis, with those involved in the healing of fractures and the development of nonunion. The key to this theory is the concept that the tissue that forms in and around a fracture should be considered a specific functional entity. This ‘bone-healing unit’ produces a physiological response to its biological and mechanical environment, which leads to the normal healing of bone. This tissue responds to mechanical forces and functions according to Wolff’s law, Perren’s strain theory and Frost’s concept of the “mechanostat”. In response to the local mechanical environment, the bone-healing unit normally changes with time, producing different tissues that can tolerate various levels of strain. The normal result is the formation of bone that bridges the fracture – healing by callus. Nonunion occurs when the bone-healing unit fails either due to mechanical or biological problems or a combination of both. In clinical practice, the majority of nonunions are due to mechanical problems with instability, resulting in too much strain at the fracture site. In most nonunions, there is an intact bone-healing unit. We suggest that this maintains its biological potential to heal, but fails to function due to the mechanical conditions. The theory predicts the healing pattern of multifragmentary fractures and the observed morphological characteristics of different nonunions. It suggests that the majority of nonunions will heal if the correct mechanical environment is produced by surgery, without the need for biological adjuncts such as autologous bone graft.

Cite this article: Bone Joint J 2016;98-B:884–91.

Osteochondritis Dissecans (OCD) is a condition for which the aetiology remains unknown. It affects subchondral bone and secondarily its overlying cartilage and is mostly found in the knee. It can occur in adults, but is generally identified when growth remains, when it is referred to as juvenile OCD. As the condition progresses, the affected subchondral bone separates from adjacent healthy bone, and can lead to demarcation and separation of its associated articular cartilage. Any symptoms which arise relate to the stage of the disease. Early disease without separation of the lesion results in pain. Separation of the lesion leads to mechanical symptoms and swelling and, in advanced cases, the formation of loose bodies.

Early identification of OCD is essential as untreated OCD can lead to the premature degeneration of the joint, whereas appropriate treatment can halt the disease process and lead to healing. Establishing the stability of the lesion is a key part of providing the correct treatment. Stable lesions, particularly in juvenile patients, have greater propensity to heal with non-surgical treatment, whereas unstable or displaced lesions usually require surgical management.

This article discusses the aetiology, clinical presentation and prognosis of OCD in the knee. It presents an algorithm for treatment, which aims to promote healing of native hyaline cartilage and to ensure joint congruity.

Take home message: Although there is no clear consensus as to the best treatment of OCD, every attempt should be made to retain the osteochondral fragment when possible as, with a careful surgical technique, there is potential for healing even in chronic lesions

Cite this article: Bone Joint J 2016;98-B:723–9.

Objectives

Nonunion is one of the most troublesome complications to treat in orthopaedics. Former authors believed that atrophic nonunion occurred as a result of lack of mesenchymal stem cells (MSCs). We evaluated the number and viability of MSCs in site of atrophic nonunion compared with those in iliac crest.