Ketamine has been used in combination with a variety of other agents for intra-articular analgesia, with promising results. However, although it has been shown to be toxic to various types of cell, there is no available information on the effects of ketamine on chondrocytes. We conducted a prospective randomised controlled study to evaluate the effects of ketamine on cultured chondrocytes isolated from rat articular cartilage. The cultured cells were treated with 0.125 mM, 0.250 mM, 0.5 mM, 1 mM and 2 mM of ketamine respectively for 6 h, 24 hours and 48 hours, and compared with controls. Changes of apoptosis were evaluated using fluorescence microscopy with a 490 nm excitation wavelength. Apoptosis and eventual necrosis were seen at each concentration. The percentage viability of the cells was inversely proportional to both the duration and dose of treatment (p = 0.002 and p = 0.009). Doses of 0.5 mM, 1 mM and 2mM were absolutely toxic. We concluded that in the absence of solid data to support the efficacy of intra-articular ketamine for the control of pain, and the toxic effects of ketamine on cultured chondrocytes shown by this study, intra-articular ketamine, either alone or in combination with other agents, should not be used to control pain. Cite this article: Bone Joint J 2014; 96-B:989–94

While the evolution of the bony skeleton of the shoulder girdle is well described, there is little information regarding the soft tissues, in particular of the rotator cuff. We dissected the shoulders of 23 different species and compared the anatomical features of the tendons of the rotator cuff. The alignment and orientation of the collagen fibres of some of the tendons were also examined histologically. The behaviour of the relevant species was studied, with particular reference to the extent and frequency of forward-reaching and overhead activity of the forelimb. In quadrupedal species, the tendons of supraspinatus, infraspinatus and teres minor were seen to insert into the greater tuberosity of the humerus separately. They therefore did not form a true rotator cuff with blending of the tendons. This was only found in advanced primates and in one unusual species, the tree kangaroo. These findings support the suggestion that the appearance of the rotator cuff in the evolutionary process parallels anatomical adaptation to regular overhead activity and the increased use of the arm away from the sagittal plane

To clarify the pathomechanisms of discogenic low back pain, the sympathetic afferent discharge originating from the L5-L6 disc via the L2 root were investigated neurophysiologically in 31 Lewis rats. Sympathetic afferent units were recorded from the L2 root connected to the lumbar sympathetic trunk by rami communicantes. The L5-L6 discs were mechanically probed, stimulated electrically to evoke action potentials and, finally, treated with chemicals to produce an inflammatory reaction. We could not obtain a response from any units in the L5-L6 discs using mechanical stimulation, but with electrical stimulation we identified 42 units consisting mostly of A-delta fibres. In some experiments a response to mechanical probing of the L5-L6 disc was recognised after producing an inflammatory reaction. This study suggests that mechanical stimulation of the lumbar discs may not always produce pain, whereas inflammatory changes may cause the disc to become sensitive to mechanical stimuli, resulting in nociceptive information being transmitted as discogenic low back pain to the spinal cord through the lumbar sympathetic trunk. This may partly explain the variation in human symptoms of degenerate discs

We describe a technique for measuring the Stiffness of regenerate bone after leg lengthening. This allows early identification of slow healing by reference to normal patterns. We determined the time of removal of the fixator from clinical and radiological information independent of the stiffness result. In a series of 30 leg lengthenings there were no refractures when the tibial stiffness had reached 15 Nm/° or the femoral stiffness 20 Nm/°. Three refractures occurred at lower stiffness values. The technique is simple to perform, will allow a reduction in plain radiography and is recommended for routine postoperative management

There have been few descriptions of the site of attachment onto the triquetrum, the so-called meniscal homologue, of the triangular fibrocartilage complex (TFCC). We have investigated the sites of attachment onto the triquetrum of 87 TFCCs collected from embalmed cadavers. All TFCCs were smoothly attached to the triquetrum. In 79 (46 cases, 90%) they were attached to the triquetrum and fifth metacarpal bone, and in eight (5 cases, 10%) they were attached widely on the articular surface of the triquetrum. It is necessary to have accurate positional information about the normal triquetrum and TFCC in order to perform arthroscopy. The meniscal homologue attached to the triquetrum is smooth in almost all cases. In about 10% of joints the TFCC is attached to the lunotriquetral ligament, either partly or completely obscuring the articular surface of the triquetrum

Dorsal root ganglion neurones with dichotomising axons are present in several species and are considered to play a role in referred pain. Clinically, patients with lesions in the lower lumbar discs occasionally complain of pain in the groin. We investigated the existence of dichotomising afferent neurones projecting axons both to the lumbar disc and to the groin skin, using the double fluorescent-labelling technique in rats. We observed neurones labelled with a tracer applied at the ventral portion of the L5-L6 disc and another tracer placed on the groin skin in L1 and L2 dorsal root ganglia. Our results showed that the double-labelled neurones had peripheral axons which dichotomised into both the L5-L6 disc and the groin skin, indicating the convergence of afferent sensory information from the disc and groin skin. Our findings provide a possible neuroanatomical mechanism for referred groin pain in patients with disc lesions

Tissue engineering is an increasingly popular method of addressing pathological disorders of cartilage. Recent studies have demonstrated its clinical efficacy, but there is little information on the structural organisation and biochemical composition of the repair tissue and its relation to the adjacent normal tissue. We therefore analysed by polarised light microscopy and immunohistochemistry biopsies of repair tissue which had been taken 12 months after implantation of autologous chondrocytes in two patients with defects of articular cartilage. Our findings showed zonal heterogeneity throughout the repair tissue. The deeper zone resembled hyaline-like articular cartilage whereas the upper zone was more fibrocartilaginous. The results indicate that within 12 months autologous chondrocyte implantation successfully produces replacement cartilage tissue, a major part of which resembles normal hyaline cartilage

It has been thought that lumbar intervertebral discs were innervated segmentally. We have previously shown that the L5-L6 intervertebral disc in the rat is innervated bilaterally from the L1 and L2 dorsal root ganglia through the paravertebral sympathetic trunks, but the pathways between the disc and the paravertebral sympathetic trunks were unknown. We have now studied the spines of 17 rats to elucidate the exact pathways. We examined serial sections of the lumbar spine using immunohistochemistry for calcitonin gene-related peptide, a sensory nerve marker. We showed that these nerve fibres from the intervertebral disc ran through the sinuvertebral nerve into the rami communicantes, not into the corresponding segmental spinal nerve. In the rat, sensory information from the lumbar intervertebral discs is conducted through rami communicantes. If this innervation pattern applies to man, simple decompression of the corresponding nerve root will not relieve discogenic pain. Anterior interbody fusion, with the denervation of rami communicantes, may be effective for such low back pain

Caveolae, specialised regions of the cell membrane which have been detected in a wide range of mammalian cells, have not been described in bone cells. They are plasmalemmal invaginations, 50 to 100 nm in size, characterised by the presence of the structural protein, caveolin, which exists as three subtypes. Caveolin-1 and caveolin-2 are expressed in a wide range of cell types whereas caveolin-3 is thought to be a muscle-specific subtype. There is little information on the precise function of caveolae, but it has been proposed that they play an important role in signal transduction. As the principal bone-producing cell, the osteoblast has been widely studied in an effort to understand the signalling pathways by which it responds to extracellular stimuli. Our aim in this study was to identify caveolae and their structural protein caveolin in normal human osteoblasts, and to determine which subtypes of caveolin were present. Confocal microscopy showed staining which was associated with the plasma membrane. Transmission electron microscopy revealed the presence of membrane invaginations of 50 to 100 nm, consistent with the appearance of caveolae. Finally, we isolated protein from these osteoblasts, and performed Western blotting using anti-caveolin primary antibodies. This revealed the presence of caveolin-1 and -2, while caveolin-3 was absent. The identification of these structures and their associated protein may provide a significant contribution to our further understanding of signal transduction pathways in osteoblasts

There is little information about the effects of extracorporeal shock-wave about application the effects (ESWA) of on normal bone physiology. We have therefore investigated the effects of ESWA on intact distal rabbit femora in vivo. The animals received 1500 shock-wave pulses each of different energy flux densities (EFD) on either the left or right femur or remained untreated. The effects were studied by bone scintigraphy, MRI and histopathological examination. Ten days after ESWA (0.5 mJ/mm. 2. and 0.9 mJ/mm. 2. EFD), local blood flow and bone metabolism were decreased, but were increased 28 days after ESWA (0.9 mJ/mm. 2. ). One day after ESWA with 0.9 mJ/mm. 2. EFD but not with 0.5 mJ/mm. 2. , there were signs of soft-tissue oedema, epiperiosteal fluid and bone-marrow oedema on MRI. In addition, deposits of haemosiderin were found epiperiosteally and within the marrow cavity ten days after ESWA. We conclude that ESWA with both 0.5 mJ/mm. 2. and 0.9 mJ/mm. 2. EFD affected the normal bone physiology in the distal rabbit femur. Considerable damaging side-effects were observed with 0.9 mJ/mm. 2. EFD on periosteal soft tissue and tissue within the bone-marrow cavity

Using a dynamic biomechanical model of malunion of the shoulder, we have determined the change in deltoid force required for abduction with various combinations of superior and posterior displacement of fractures of the greater tuberosity of the humerus. We tested eight fresh human cadaver shoulders in a dynamic shoulder-testing apparatus during cycles of glenohumeral abduction from 0° to 90°. The greater tuberosities were osteotomised and stabilised to represent malunion with combinations of superior and posterior displacements of 1 cm and less. The peak force was measured for each displacement in each specimen and statistically compared with values of no displacement using a repeated-measures analysis of variance. The abduction force was significantly increased by 16% (p = 0.006) and 27% (p = 0.0001) by superior displacements of 0.5 cm and 1 cm, respectively, while combined superior and posterior displacement of 1 cm gave an increase in force of 29% (p = 0.001). While treatment criteria for acceptable residual displacement of the greater tuberosity are widely used, there is little information on the direct biomechanical effects of displacement on shoulder mechanics. Although the results of conservative treatment are influenced by a number of factors, including associated injuries, rehabilitation and the pre-existing function of the shoulder, our data suggest that small amounts of residual displacement may alter the balance of forces required to elevate the arm at the glenohumeral joint

The use of impacted, morsellised bone grafts has become popular in revision total hip arthroplasty (THA). The initial stability of the reconstruction and the effectiveness of any subsequent process of revitalisation and incorporation will depend on the mechanical integrity of the graft. Our aim in this study was to document the time-dependent mechanical properties of the morsellised graft. This information is useful in clinical application of the graft, in studies of migration of the implant and in the design of the joint. We used 16 specimens of impacted, morsellised cancellous bone from the sternum of goats to assess the mechanical properties by confined compression creep tests. Consideration of the graft material as a porous, permeable solid, filled with fluid, allowed determination of the compressive modulus of the matrix, and its permeability to fluid flow. In all specimens the compression tests showed large, irreversible deformations, caused by flow-independent creep behaviour as a result of rolling and sliding of the bone chips. The mean permeability was 8.82 *10. −12. m. 4. /Ns (SD 43%), and the compressive modulus was 38.7 MPa (SD 34%). No correlation was found between the apparent density and the permeability or between the apparent density and the compressive modulus. The irreversible deformations in the graft could be captured by a creep law, for which the parameters were quantified. We conclude that in clinical use the graft is bound to be subject to permanent deformation after operation. The permeability of the material is relatively high compared with, for example, human cartilage. The confined compression modulus is relatively low compared with cancellous bone of the same apparent density. Designs of prostheses used in revision surgery must accommodate the viscoelastic and permanent deformations in the graft without causing loosening at the interface

Aims

The intra-articular administration of tranexamic acid (TXA) has been shown to be effective in reducing blood loss in unicompartmental knee arthroplasty and anterior cruciate reconstruction. The effects on human articular cartilage, however, remains unknown. Our aim, in this study, was to investigate any detrimental effect of TXA on chondrocytes, and to establish if there was a safe dose for its use in clinical practice. The hypothesis was that TXA would cause a dose-dependent damage to human articular cartilage.

Rebound growth after hemiepiphysiodesis may be a normal event, but little is known about its causes, incidence or factors related to its intensity. The aim of this study was to evaluate rebound growth under controlled experimental conditions.

A total of 22 six-week-old rabbits underwent a medial proximal tibial hemiepiphysiodesis using a two-hole plate and screws. Temporal growth plate arrest was maintained for three weeks, and animals were killed at intervals ranging between three days and three weeks after removal of the device. The radiological angulation of the proximal tibia was studied at weekly intervals during and after hemiepiphysiodesis. A histological study of the retrieved proximal physis of the tibia was performed.

The mean angulation achieved at three weeks was 34.7° (standard deviation (sd) 3.4), and this remained unchanged for the study period of up to two weeks. By three weeks after removal of the implant the mean angulation had dropped to 28.2° (sd 1.8) (p < 0.001). Histologically, widening of the medial side was noted during the first two weeks. By three weeks this widening had substantially disappeared and the normal columnar structure was virtually re-established.

In our rabbit model, rebound was an event of variable incidence and intensity and, when present, did not appear immediately after restoration of growth, but took some time to appear.

Cite this article: Bone Joint J 2015;97-B:862–8.

Trauma and orthopaedics is the largest of the surgical specialties and yet attracts a disproportionately small fraction of available national and international funding for health research. With the burden of musculoskeletal disease increasing, high-quality research is required to improve the evidence base for orthopaedic practice. Using the current research landscape in the United Kingdom as an example, but also addressing the international perspective, we highlight the issues surrounding poor levels of research funding in trauma and orthopaedics and indicate avenues for improving the impact and success of surgical musculoskeletal research.

Cite this article: Bone Joint J 2014; 96-B:1578–85.

The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed.

In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups.

After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate.

Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes.

Cite this article: Bone Joint J 2014; 96-B:845–50.

We welcome letters to the Editor concerning articles that have recently been published. Such letters will be subject to the usual stages of selection and editing; where appropriate the authors of the original article will be offered the opportunity to reply.

We implanted titanium and carbon fibre-reinforced plastic (CFRP) femoral prostheses of the same dimensions into five prosthetic femora. An abductor jig was attached and a 1 kN load applied. This was repeated with five control femora. Digital image correlation was used to give a detailed two-dimensional strain map of the medial cortex of the proximal femur. Both implants caused stress shielding around the calcar. Distally, the titanium implant showed stress shielding, whereas the CFRP prosthesis did not produce a strain pattern which was statistically different from the controls. There was a reduction in strain beyond the tip of both the implants.

This investigation indicates that use of the CFRP stem should avoid stress shielding in total hip replacement.

In an osteological collection of 3100 specimens, 70 were found with unilateral clavicular fractures which were matched with 70 randomly selected normal specimens. This formed the basis of a study of the incidence of arthritis of the acromioclavicular joint and the effect of clavicular fracture on the development of arthritis in the ipsilateral acromioclavicular joint. This was graded visually on a severity scale of 0 to 3. The incidence of moderate to severe arthritis of the acromioclavicular joint in normal specimens was 77% (100 specimens). In those with a clavicular fracture, 66 of 70 (94%) had arthritis of the acromioclavicular joint, compared to 63 of 70 (90%) on the non-injured contralateral side (p = 0.35).

Clavicles with shortening of 15 mm or less had no difference in the incidence of arthritis compared to those with shortening greater than 15 mm (p = 0.25). The location of the fracture had no effect on the development of arthritis.

The medial periosteal hinge plays a key role in fractures of the head of the humerus, offering mechanical support during and after reduction and maintaining perfusion of the head by the vessels in the posteromedial periosteum. We have investigated the biomechanical properties of the medial periosteum in fractures of the proximal humerus using a standard model in 20 fresh-frozen cadaver specimens comparable in age, gender and bone mineral density. After creating the fracture, we displaced the humeral head medial or lateral to the shaft with controlled force until complete disruption of the posteromedial periosteum was recorded. As the quality of periosteum might be affected by age and bone quality, the results were correlated with the age and the local bone mineral density of the specimens measured with quantitative CT.

Periosteal rupture started at a mean displacement of 2.96 mm (sd 2.92) with a mean load of 100.9 N (sd 47.1). The mean maximum load of 111.4 N (sd 42.5) was reached at a mean displacement of 4.9 mm (sd 4.2). The periosteum was completely ruptured at a mean displacement of 34.4 mm (sd 11.1). There was no significant difference in the mean distance to complete rupture for medial (mean 35.8 mm (sd 13.8)) or lateral (mean 33.0 mm (sd 8.2)) displacement (p = 0.589).

The mean bone mineral density was 0.111 g/cm³ (sd 0.035). A statistically significant but low correlation between bone mineral density and the maximum load uptake (r = 0.475, p = 0.034) was observed.

This study showed that the posteromedial hinge is a mechanical structure capable of providing support for percutaneous reduction and stabilisation of a fracture by ligamentotaxis. Periosteal rupture started at a mean of about 3 mm and was completed by a mean displacement of just under 35 mm. The microvascular situation of the rupturing periosteum cannot be investigated with the current model.