This study was undertaken to elucidate the mechanism of biological repair at the tendon-bone junction in a rat model. The stump of the toe flexor tendon was sutured to a drilled hole in the tibia (tendon suture group, n = 23) to investigate healing of the tendon-bone junction both radiologically and histologically. Radiological and histological findings were compared with those observed in a sham control group where the bone alone was drilled (n = 19). The biomechanical strength of the repaired junction was confirmed by pull-out testing six weeks after surgery in four rats in the tendon suture group. Callus formation was observed at the site of repair in the tendon suture group, whereas in the sham group callus formation was minimal. During the pull-out test, the repaired tendon-bone junction did not fail because the musculotendinous junction always disrupted first. In order to understand the factors that influenced callus formation at the site of repair, four further groups were evaluated. The nature of the sutured tendon itself was investigated by analysing healing of a tendon stump after necrosis had been induced with liquid nitrogen in 16 cases. A proximal suture group (n = 16) and a partial tenotomy group (n = 16) were prepared to investigate the effects of biomechanical loading on the site of repair. Finally, a group where the periosteum had been excised at the site of repair (n = 16) was examined to study the role of the periosteum. These four groups showed less callus formation radiologically and histologically than did the tendon suture group. In conclusion, the sutured tendon-bone junction healed and achieved mechanical strength at six weeks after suturing, showing good local callus formation. The viability of the tendon stump, mechanical loading and intact periosteum were all found to be important factors for better callus formation at a repaired tendon-bone junction

In patients with traumatic brain injury and fractures of long bones, it is often clinically observed that the rate of bone healing and extent of callus formation are increased. However, the evidence has been unconvincing and an association between such an injury and enhanced fracture healing remains unclear. We performed a retrospective cohort study of 74 young adult patients with a mean age of 24.2 years (16 to 40) who sustained a femoral shaft fracture (AO/OTA type 32A or 32B) with or without a brain injury. All the fractures were treated with closed intramedullary nailing. The main outcome measures included the time required for bridging callus formation (BCF) and the mean callus thickness (MCT) at the final follow-up. Comparative analyses were made between the 20 patients with a brain injury and the 54 without brain injury. Subgroup comparisons were performed among the patients with a brain injury in terms of the severity of head injury, the types of intracranial haemorrhage and gender. Patients with a brain injury had an earlier appearance of BCF (p < 0.001) and a greater final MCT value (p < 0.001) than those without. There were no significant differences with respect to the time required for BCF and final MCT values in terms of the severity of head injury (p = 0.521 and p = 0.153, respectively), the types of intracranial haemorrhage (p = 0.308 and p = 0.189, respectively) and gender (p = 0.383 and p = 0.662, respectively). These results confirm that an injury to the brain may be associated with accelerated fracture healing and enhanced callus formation. However, the severity of the injury to the brain, the type of intracranial haemorrhage and gender were not statistically significant factors in predicting the rate of bone healing and extent of final callus formation

A case of hyperplastic callus formation is reported in a girl of eleven; several bones were affected. There were no associated fractures. She is believed to be suffering from a mild non-familial type of osteogenesis imperfecta without blue sclerotics and presents multiple bony excrescences unassociated with injury. The relevant literature is reviewed. The effect of a trial of treatment with A.C.T.H. and with deep x-ray is reported

In osteogenesis imperfecta the formation of callus is usually plentiful and sometimes rather excessive but the excess is absorbed in the normal way as consolidation occurs. In hyperplastic callus formation the amount of callus formed is large, or even enormous; and, once its limits are defined and ossification has occurred, some part of the original swelling remains as a thickening of the bone. "Callus" may form with or without injury and with or without fracture. The interest of the present case lies partly in the fact that there is no history of multiple fractures to indicate classical osteogenesis imperfecta, and partly in the familial incidence which has also been noted in other records. It is important to recognise the true nature of the condition in order to avoid the tragedy of unnecessary amputation. In one of Brailsford's cases the lesion is said to have become malignant but there is no other evidence in the literature that the condition has any relationship to malignancy. The clinical appearance can easily give rise to the suspicion of malignancy, and on histological examination the highly cellular and rapidly growing callus can be confused with a malignant condition. In fact, for the short time in which the bone formation runs riot the behaviour of a malignant neoplasm is closely simulated. It is thought that the present account may be of interest because of the invariable relief of pain after x-ray treatment of each new lesion, the length of time over which the case has been followed and the resemblance between the radiographic appearances in the patient now and those of her aunt taken twenty years ago

Callus formation and the rate of union of nailed fractures of the femur has been determined in 22 patients with associated head injuries and compared with that in a group of patients with similarly treated fractures but without head injuries. The comparison confirms the widely held view that, in patients with head injuries, fractures frequently heal with excessive callus and at a faster rate than normal

This study investigated the quality and quantity of healing of a bone defect following intramedullary reaming undertaken by two fundamentally different systems; conventional, using non-irrigated, multiple passes; or suction/irrigation, using one pass. The result of a measured re-implantation of the product of reaming was examined in one additional group. We used 24 Swiss mountain sheep with a mean tibial medullary canal diameter between 8 mm and 9 mm. An 8 mm ‘napkin ring’ defect was created at the mid-diaphysis. The wound was either surgically closed or occluded. The medullary cavity was then reamed to 11 mm. The Reamer/Irrigator/Aspirator (RIA) System was used for the reaming procedure in groups A (RIA and autofilling) and B (RIA, collected reamings filled up), whereas reaming in group C (Synream and autofilling) was performed with the Synream System. The defect was allowed to auto-fill with reamings in groups A and C, but in group B, the defect was surgically filled with collected reamings. The tibia was then stabilised with a solid locking Unreamed Humerus Nail (UHN), 9.5 mm in diameter. The animals were killed after six weeks. After the implants were removed, measurements were taken to assess the stiffness, strength and callus formation at the site of the defect. There was no significant difference between healing after conventional reaming or suction/irrigation reaming. A significant improvement in the quality of the callus was demonstrated by surgically placing captured reamings into the defect using a graft harvesting system attached to the aspirator device. This was confirmed by biomechanical testing of stiffness and strength. This study suggests it could be beneficial to fill cortical defects with reaming particles in clinical practice, if feasible

The experiments showed that the administration of sodium citrate retards fracture healing. This is probably due to a change in the solubility of the calcium or to a relative calcium deficiency on account of the excretion in the urine, or to a combination of both factors. Other reasons cannot, however, be excluded, such as a biochemical effect on the ground substance or an enzyme deficiency.

Lengthening of the humerus is now an established technique. We compared the complications of humeral lengthening with those of femoral lengthening and investigated whether or not the callus formation in the humerus proceeds at a higher rate than that in the femur. A total of 24 humeral and 24 femoral lengthenings were performed on 12 patients with achondroplasia. We measured the pixel value ratio (PVR) of the lengthened area on radiographs and each radiograph was analysed for the shape, type and density of the callus. The quality of life (QOL) of the patients after humeral lengthening was compared with that prior to surgery. The complication rate per segment of humerus and femur was 0.87% and 1.37%, respectively. In the humerus the PVR was significantly higher than that of the femur. Lower limbs were associated with an increased incidence of concave, lateral and central callus shapes. Humeral lengthening had a lower complication rate than lower-limb lengthening, and QOL increased significantly after humeral lengthening. Callus formation in the humerus during the distraction period proceeded at a significantly higher rate than that in the femur. . These findings indicate that humeral lengthening has an important role in the management of patients with achondroplasia

Aims. Given the possible radiation damage and inaccuracy of radiological investigations, particularly in children, ultrasound and superb microvascular imaging (SMI) may offer alternative methods of evaluating new bone formation when limb lengthening is undertaken in paediatric patients. The aim of this study was to assess the use of ultrasound combined with SMI in monitoring new bone formation during limb lengthening in children. Methods. In this retrospective cohort study, ultrasound and radiograph examinations were performed every two weeks in 30 paediatric patients undergoing limb lengthening. Ultrasound was used to monitor new bone formation. The number of vertical vessels and the blood flow resistance index were compared with those from plain radiographs. Results. We categorized the new bone formation into three stages: stage I (early lengthening), in which there was no obvious callus formation on radiographs and ultrasound; stage II (lengthening), in which radiographs showed low-density callus formation with uneven distribution and three sub-stages could be identified on ultrasound: in Ia punctate callus was visible; in IIb there was linear callus formation which was not yet connected and in IIc there was continuous linear callus. In stage III (healing), the bone ends had united, the periosteum was intact, and the callus had disappeared, as confirmed on radiographs, indicating healed bone. A progressive increase in the number of vertical vessels was noted in the early stages, peaking during stages IIb and IIc, followed by a gradual decline (p < 0.001). Delayed healing involved patients with a prolonged stage IIa or those who regressed to stage IIa from stages IIb or IIc during lengthening. Conclusion. We found that the formation of new bone in paediatric patients undergoing limb lengthening could be reliably evaluated using ultrasound when combined with the radiological findings. This combination enabled an improved assessment of the prognosis, and adjustments to the lengthening protocol. While SMI offered additional insights into angiogenesis within the new bone, its role primarily contributed to the understanding of the microvascular environment rather than directly informing adjustments of treatment. Cite this article: Bone Joint J 2024;106-B(7):751–758

Extensive limb lengthening may be indicated in achondroplastic patients who wish to achieve a height within the normal range for their population. However, increasing the magnitude of lengthening is associated with further complications particularly adjacent joint stiffness and fractures. We studied the relationship between the magnitude of femoral lengthening and callus pattern, adjacent joint stiffness and fracture of the regenerate bone in 40 femoral lengthenings in 20 achondroplastic patients. They were divided into two groups; group A had lengthening of less than 50% and group B of more than 50% of their initial femoral length. The patterns of radiological callus formation were classified according to shape, type and features. The incidence of callus features, knee stiffness and regenerate bone fracture were analysed in the two groups. Group B was associated with an increased incidence of concave, lateral and central callus shapes, adjacent joint and stiffness and fracture. Statistically, the incidence of stiffness in adjacent joints and regenerate bone fracture was significantly associated with the magnitude of lengthening. We suggest that careful radiological assessment of the patterns of callus formation is a useful method for the evaluation and monitoring of regenerate bone

The traditional techniques involving an oblique tunnel or triangular wedge resection to approach a central or mixed-type physeal bar are hindered by poor visualisation of the bar. This may be overcome by a complete transverse osteotomy at the metaphysis near the growth plate or a direct vertical approach to the bar. Ilizarov external fixation using small wires allows firm fixation of the short physis-bearing fragment, and can also correct an associated angular deformity and permit limb lengthening. . We accurately approached and successfully excised ten central- or mixed-type bars; six in the distal femur, two in the proximal tibia and two in the distal tibia, without damaging the uninvolved physis, and corrected the associated angular deformity and leg-length discrepancy. Callus formation was slightly delayed because of periosteal elevation and stretching during resection of the bar. The resultant resection of the bar was satisfactory in seven patients and fair in three as assessed using a by a modified Williamson–Staheli classification. Cite this article: Bone Joint J 2015;97-B:1726–31

We prospectively evaluated the one- and seven-year results of the Weil osteotomy for the treatment of metatarsalgia with subluxed or dislocated metatarsophalangeal joints in 25 feet of 24 patients. Good to excellent results were achieved in 21 feet (84%) after one year and in 22 (88%) after seven years. The American Orthopaedic Foot and Ankle Society score significantly improved from 48 (. sd. 15) points before surgery to 75 (. sd. 24) at one year, and 83 (. sd. 18) at seven years. The procedure significantly reduced pain, diminished isolated plantar callus formation and increased the patient’s capacity for walking. Redislocation of the metatarsophalangeal joint was seen in two feet (8%) after one year and in three (12%) after seven years. Although floating toes and restricted movement of the metatarsophalangeal joint may occur, the Weil osteotomy is safe and effective

Fracture repair occurs by two broad mechanisms: direct healing, and indirect healing with callus formation. The effects of bisphosphonates on fracture repair have been assessed only in models of indirect fracture healing. A rodent model of rigid compression plate fixation of a standardised tibial osteotomy was used. Ten skeletally mature Sprague–Dawley rats received daily subcutaneous injections of 1 µg/kg ibandronate (IBAN) and ten control rats received saline (control). Three weeks later a tibial osteotomy was rigidly fixed with compression plating. Six weeks later the animals were killed. Fracture repair was assessed with mechanical testing, radiographs and histology. The mean stress at failure in a four-point bending test was significantly lower in the IBAN group compared with controls (8.69 Nmm. -2. (. sd. 7.63) vs 24.65 Nmm. -2. (. sd. 6.15); p = 0.017). On contact radiographs of the extricated tibiae the mean bone density assessment at the osteotomy site was lower in the IBAN group than in controls (3.7 mmAl (. sd. 0.75) vs 4.6 mmAl (. sd. 0.57); p = 0.01). In addition, histological analysis revealed progression to fracture union in the controls but impaired fracture healing in the IBAN group, with predominantly cartilage-like and undifferentiated mesenchymal tissue (p = 0.007). . Bisphosphonate treatment in a therapeutic dose, as used for risk reduction in fragility fractures, had an inhibitory effect on direct fracture healing. We propose that bisphosphonate therapy not be commenced until after the fracture has united if the fracture has been rigidly fixed and is undergoing direct osteonal healing. Cite this article: Bone Joint J 2013;95-B:1263–8

The management of osteonecrosis of the femoral head ranges from symptomatic therapy to total hip replacement. Conservative treatment is effective only in small, early-stage lesions. Free vascularised fibular grafting has provided more consistently successful results than any other joint-preserving method. It supports the collapsing subchondral plate by primary callus formation, reduces intra-osseous pressure, removes and replaces the necrotic segment, and adds viable cortical bone graft plus fresh cancellous graft, which has osseoinductive and osseoconductive potential. Factors predisposing to success are the aetiology, stage and size of the lesion. Furthermore, it is a hip-salvaging procedure in early pre-collapse stages, and a time-buying one when the femoral head has collapsed

We report the results of using a combination of fixator-assisted nailing with lengthening over an intramedullary nail in patients with tibial deformity and shortening. Between 1997 and 2007, 13 tibiae in nine patients with a mean age of 25.4 years (17 to 34) were treated with a unilateral external fixator for acute correction of deformity, followed by lengthening over an intramedullary nail with a circular external fixator applied at the same operating session. At the end of the distraction period locking screws were inserted through the intramedullary nail and the external fixator was removed. The mean amount of lengthening was 5.9 cm (2 to 8). The mean time of external fixation was 90 days (38 to 265). The mean external fixation index was 15.8 days/cm (8.9 to 33.1) and the mean bone healing index was 38 days/cm (30 to 60). One patient developed an equinus deformity which responded to stretching and bracing. Another developed a drop foot due to a compartment syndrome, which was treated by fasciotomy. It recovered in three months. Two patients required bone grafting for poor callus formation. We conclude that the combination of fixator-assisted nailing with lengthening over an intramedullary nail can reduce the overall external fixation time and prevent fractures and deformity of the regenerated bone

For the treatment of ununited fractures, we developed a system of delivering magnetic labelled mesenchymal stromal cells (MSCs) using an extracorporeal magnetic device. In this study, we transplanted ferucarbotran-labelled and luciferase-positive bone marrow-derived MSCs into a non-healing femoral fracture rat model in the presence of a magnetic field. The biological fate of the transplanted MSCs was observed using luciferase-based bioluminescence imaging and we found that the number of MSC derived photons increased from day one to day three and thereafter decreased over time. The magnetic cell delivery system induced the accumulation of photons at the fracture site, while also retaining higher photon intensity from day three to week four. Furthermore, radiological and histological findings suggested improved callus formation and endochondral ossification. We therefore believe that this delivery system may be a promising option for bone regeneration

We report our experience with carbon-fibre reinforced plastic (CFRP) plates in the management of 19 problem fractures complicated by either infection, nonunion, comminution or contamination. The combination offers secure fixation without inhibition of callus formation

1. Experimental fracture callus in rats contains mast cells as a normal morphological element. 2. The mast cell count undergoes peculiar variations in the normal course of events in experimentally delayed or accelerated bone repair. 3. A hypothesis is presented in which the tissue mast cell granules are regarded as calcium transporters in the mineral phase of callus formation, a process probably corresponding to Selye's concept of "mastocalciphylaxis" and "mastocalcergy."

1. Two girls with non-familial osteogenesis imperfecta who subsequently developed osteosarcoma of the femur are described. One is of special interest in that there were multiple bone metastases. 2. It is suggested that the tumours arose spontaneously and were not related to the underlying bone disorder. 3. Because of the relative frequency of hyperplastic callus formation in osteogenesis imperfecta it is most important that adequate biopsy material of any suspicious lesion is examined because the early clinical picture may be indistinguishable from a tumour

Two types of fracture, early and late, have been reported following limb lengthening in patients with achondroplasia (ACH) and hypochondroplasia (HCH). . We reviewed 25 patients with these conditions who underwent 72 segmental limb lengthening procedures involving the femur and/or tibia, between 2003 and 2011. Gender, age at surgery, lengthened segment, body mass index, the shape of the callus, the amount and percentage of lengthening and the healing index were evaluated to determine predictive factors for the occurrence of early (within three weeks after removal of the fixation pins) and late fracture (> three weeks after removal of the pins). The Mann‑Whitney U test and Pearson’s chi-squared test for univariate analysis and stepwise regression model for multivariate analysis were used to identify the predictive factor for each fracture. Only one patient (two tibiae) was excluded from the analysis due to excessively slow formation of the regenerate, which required supplementary measures. A total of 24 patients with 70 limbs were included in the study. There were 11 early fractures in eight patients. The shape of the callus (lateral or central callus) was the only statistical variable related to the occurrence of early fracture in univariate and multivariate analyses. Late fracture was observed in six limbs and the mean time between removal of the fixation pins and fracture was 18.3 weeks (3.3 to 38.4). Lengthening of the tibia, larger healing index, and lateral or central callus were related to the occurrence of a late fracture in univariate analysis. A multivariate analysis demonstrated that the shape of the callus was the strongest predictor for late fracture (odds ratio: 19.3, 95% confidence interval: 2.91 to 128). Lateral or central callus had a significantly larger risk of fracture than fusiform, cylindrical, or concave callus. Radiological monitoring of the shape of the callus during distraction is important to prevent early and late fracture of lengthened limbs in patients with ACH or HCH. In patients with thin callus formation, some measures to stimulate bone formation should be considered as early as possible. Cite this article: Bone Joint J 2014;96-B:1269–73

The clinical results of 26 digits (18 patients) lengthened by distraction callotasis were evaluated and the factors which influenced healing were analysed. There were 14 men and four women, with a mean age of 39 years. All digits had suffered traumatic amputation. There were eight thumbs and 18 fingers. The level of the site of the osteotomy was at the proximal metaphysis in ten, the middle diaphysis in 13 and the distal metaphysis in three. Although the proposed length was achieved in 23 of the 26 digits, five required additional bone grafts. The rate of healing was 96 days/cm in the digits without complications such as callus fracture or poor callus formation, and 158 days/cm in those with complications. Lengthening at the proximal metaphysis gave a better result than at the diaphysis or distal metaphysis

The lumbar spines of 485 skeletons of adult South African "Whites" and "Blacks" of both sexes were examined to determine the incidence and morphology of defects in the pars interarticularis. The overall incidence was 3.5%, without significant variation between races and sexes. The incidence of lumbar spina bifida in the whole sample was 1.9%, but was 11.8% in those skeletons with spondylolysis. Some instances of unilateral spondylolysis demonstrated obvious callus formation, suggesting a capability for normal repair. It is possible that the defects in bilateral cases represent established non-union of fractures of the pars interarticularis resulting from excessive mobility, and are not due to dysplasia of bone. It is noted, for the first time, that the superior facets of affected vertebrae are abnormally enlarged, and that the inferior facets of the separate neural arch are characteristically elliptical

Vitamin D metabolite levels were measured in serum and bone samples obtained from 27 patients undergoing elective bony procedures and from 28 patients operated on after a fracture. Serum 25 hydroxyvitamin D3 (25-OH-D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) did not differ significantly between the elective and fracture patients, but serum 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) was significantly reduced in the fracture patients. Very little 25-OH-D3 was found in bone, although it was the major vitamin D metabolite in serum (90%). In elective patients bone levels of 24,25(OH)2D3 and 1,25(OH)2D3 were similar to those in serum; however, in bone from around pertrochanteric fractures, but not from subcapital or patellar fractures, the concentrations of these compounds were considerably increased. These findings may shed light on the mechanism of callus formation and on the role of vitamin D metabolites in bone healing

The results obtained with a lightweight dynamic axial fixator in the treatment of fractures are reported. The apparatus comprises a single bar with articulating ends which clamp self-tapping screws and can be locked at an angle appropriate for axial alignment. A telescopic facility allows ready conversion from rigid to dynamic fixation once periosteal callus formation has commenced. Reduction and controlled distraction or compression are achieved by means of a detachable compressor unit. We treated 288 patients with fresh fractures and 50 with ununited fractures. The success rate for fresh fractures was 94%, with average healing times ranging from 3.4 to 6.5 months. In ununited fractures also, the success rate was 94% with average healing times ranging from 4.7 to 6.5 months. Complications were minimal. The device is versatile and can be applied in an average of 15 minutes. It permits ambulatory fracture care without sacrificing a sound anatomical result

The histology and mechanics of leg lengthening by callus distraction were studied in 27 growing rabbits. Tibial diaphyses were subjected to subperiosteal osteotomy, held in a neutral position for 10 days and then slowly distracted at 0.25 mm/12 hours, using a dynamic external fixator. Radiographs showed that the gap became filled with callus having three distinct zones. Elongation appeared to occur in a central radiolucent zone; this was bounded by two sclerotic zones. Histologically, the radiolucent zone consisted of longitudinally arranged cartilage and fibrous tissue while the sclerotic zones were formed by fine cancellous bone. New bone occasionally contained islands of cartilage, suggesting it had been formed by endochondral ossification. After completion of distraction, the two sclerotic zones fused, shrank and were eventually absorbed, leaving tubular bone with a new cortex. When the periosteum had been removed at the operation, callus formation was markedly disturbed and there was failure of bone lengthening. Scraping of endosteum, in contrast, did not have a pronounced effect. These results suggest that the preservation of periosteum is essential if bone lengthening by callus distraction is to succeed, and that preservation of the periosteum is more important than careful corticotomy

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

1. The healing of the radius and tibia in dogs after compression plating of osteotomies made by a Gigli saw was studied. 2. The methods used were indian ink microangiography and terramycin labelling. The Spalteholz technique and azane colouring were used. 3. Revascularisaton of the fracture region took place both from newly formed vessels in the Haversian systems and from periosteal and endosteal vessels. 4. The fracture gap was filled at an early stage by a vascular network. Under stable conditions direct angiogenic bone formation took place around this network. 5. Rebuilding of the cortical bone in the fracture region occurred by osteoclastic activity. Groups of osteoclasts made cavities in the necrotic bone and were immediately followed by loops of vessels; behind and around the loop new bone was formed. Another form of bone absorption consisted of bundles of vessels which eroded necrotic cortical bone without new bone formation. 6. The new bone was initially oriented along the fracture gap but, by conversion into secondary osteones, it became progressively oriented longitudinally in the direction of the original bone. 7. Under stable conditions some periosteal and endosteal callus formation occurred though it was of slight importance. It regressed very soon and was seldom seen in the radiographs

1 . Implants of heterogenous cartilage are known to excite a foreign body reaction in host tissues. In these experiments the way such implants hinder the spread of ossification across a fracture gap was studied. A segment of bone and periosteum was excised from both fibulae in twelve young grivet monkeys, and epiphysial cartilage from a four-day- old rat was implanted in the gap on the left side. The repair processes were investigated at intervals up to twenty-eight weeks. 2. On both sides the gaps were filled by fibrous tissue growing in from the adjacent muscle, and four weeks elapsed before callus started to form. Thereafter ossification across the gap was active on the right side, with bony union in seven or eight weeks. 3. On the left side the implant was slowly resorbed by macrophages and giant cells. Ossification made little headway in the gap after the seventh week. Remains of the implant were found up to the end of the period covered by the experiment. The ends of the fragments were united by fibrous tissue. 4. The fifth to the eighth week seemed to be a critical period, during which the implant and its surrounding inflammatory cells hindered chondrification and ossification and prevented fusion of the masses of callus at the ends of the fragments. 5. It is concluded that anything that impedes callus formation across the fracture line during this critical period may lead to non-union

1. Osteogenesis imperfecta is characterised by osseous fragility. Patients with the "congenita" form have multiple fractures before birth; those with the "tarda" form have osteoporosis, and develop multiple fractures and milder deformities of long bones at varying times after birth. 2. The frequency of blue sclera, dentinogenesis imperfecta, bruising, ligamentous laxity, and deafness are recorded in sixty patients seen at the Hospital for Sick Children, Toronto, from 1949 to 1969. The major orthopaedic deformities of long bones were antero-lateral bowing of femur and anterior bowing (sabre shin) of tibia. 3. The incidence of scoliosis (40 per cent) is high in osteogenesis imperfecta. Two patients, one in Toronto and one in Seattle, have had Harrington instrumentation and fusion for this. 4. Fractures were commonest in the femur and tibia and few in the cervical spine and femoral neck. There were four cases of disturbing hyperplastic callus formation. 5. Twenty-one patients were operated on for long bone deformities and recurrent fractures by the Sofield technique. Despite extensive subperiosteal dissection non-union is rare (four cases). Fourteen of twenty-one patients so treated are able to walk, with or without assistance. Surgical intervention to both correct and prevent deformities is justified. 6. Patients with osteogenesis imperfecta compensated for their disability by reasonable academic achievement and by choosing a sedentary occupation

1. Cell differentiation around screws manufactured by two American and two Swiss companies and inserted into seventy femora in forty-one adult mongrel dogs has been observed over periods varying between two weeks and nine months. 2. This study reveals that, despite their excellent holding power, such screws are not everywhere in firm contact with the surrounding bone at the time of insertion. Indeed, only part of the thread surface facing the head of the screw touches the compact bone, all other surfaces being separated by a space up to 150 µ in thickness. 3. These spaces result both from the surgical technique employed and from the inaccurate measurements of drills, screws and taps. 4. Migrating cells invade these spaces during the first two weeks. In the absence of movement, these cells differentiate into osteogenic cells; movement leads to differentiation into fibroblasts, chondroblasts and osteoclasts, and failure of fixation ensues. In contrast, callus formation by osteogenic cells firmly anchors screws in four to five weeks, well before callus uniting the bone fragments has been established. 5. Extremities should be protected from undue stresses during those first few weeks after osteosynthesis, whatever the technique. 6. This study clearly demonstrates the importance oftesting screws in living bone to ascertain their holding power at all stages of fracture healing

We report the outcome of 19 children aged 5.2 to 13.2 years with 20 fractures of the femoral shaft requiring surgery, who were randomly assigned to have external fixation (EF) or flexible intramedullary nailing (FIN) (10 fractures each). The duration of the operation averaged 56 minutes for the EF group with 1.4 minutes of fluoroscopy, compared with 74 minutes and 2.6 minutes, respectively, for the FIN group. The early postoperative course was similar, but the EF group showed much more callus formation. The time to full weight-bearing, full range of movement and return to school were all shorter in the FIN group. The FIN complications included one transitory foot drop and two cases of bursitis at an insertion site. In the EF group there was one refracture, one rotatory malunion requiring remanipulation and two pin-track infections. At an average follow-up of 14 months two patients in the EF group had mild pain, four had quadriceps wasting, one had leg-length discrepancy of over 1 cm, four had malalignment of over 5°, and one had limited hip rotation. In the FIN group, one patient had mild pain and one had quadriceps wasting; there were no length discrepancies, malalignment or limitation of movement. Parents of the FIN group were more satisfied. We recommend the use of flexible intramedullary nailing for fractures of the femoral shaft which require surgery, and reserve external fixation for open or severely comminuted fractures

1. Transplantations of autografts and of Kiel bone to the iliac bone and to muscle tissue were performed in rabbits. Through labelling with two tetracycline compounds which have different fluorescent colours in ultraviolet light, bone formation between the labelling periods could be followed. 2. It was shown that bone formation between the fifth and the tenth day after transplantation to bone took place in about 50 per cent of the fresh autografts. Storage of the transplants in saline for one hour before replacement had little adverse effect, whereas exposure to air for one hour seemed to reduce the osteogenic effect of the grafts. Bone formation was not observed in grafts of Kiel bone during this period. 3. The fact that new bone formation in fresh autografts could be demonstrated even during the first four days after transplantation to bone indicates that osteogenic cells from the fresh autografts continue their activity under favourable conditions. This is supported by microradiographic and histological evidence. 4. The amount of callus which developed in close contact with the grafts during the first ten days after transplantation to bone was more pronounced both in fresh autografts and in autografts kept in saline than in autografts exposed to air for one hour. Callus developing at a later stage showed no significant difference between the various grafts, including those of Kiel bone. 5. In fresh autografts transplanted to muscle tissue callus formation could be demonstrated in most cases by the tenth day, indicating either survival of osteoblasts or the transformation of more primitive cells from the graft or from the host bone into osteogenic cells. No bone formation was observed when Kiel bone was embedded in muscle tissue

Aims

Revision total hip arthroplasty in patients with Vancouver type B3 fractures with Paprosky type IIIA, IIIB, and IV femoral defects are difficult to treat. One option for Paprovsky type IIIB and IV defects involves modular cementless, tapered, revision femoral components in conjunction with distal interlocking screws. The aim of this study was to analyze the rate of reoperations and complications and union of the fracture, subsidence of the stem, mortality, and the clinical outcomes in these patients.

Aims

The aims of this study were to characterize the incidence and risk factors associated with stress fractures following periacetabular osteotomy, and to determine their effect on osteotomy union.

Aims

To clarify the effectiveness of the induced membrane technique (IMT) using beta-tricalcium phosphate (β-TCP) for reconstruction of segmental bone defects by evaluating clinical and radiological outcomes, and the effect of defect size and operated site on surgical outcomes.

Aims

The incidence of atypical femoral fractures (AFFs) continues to increase. However, there are currently few long-term studies on the complications of AFFs and factors affecting them. Therefore, we attempted to investigate the outcomes, complications, and risk factors for complication through mid-term follow-up of more than three years.

Aims

Type IIIB open tibial fractures are devastating high-energy injuries. At initial debridement, the surgeon will often be faced with large bone fragments with tenuous, if any, soft-tissue attachments. Conventionally these are discarded to avoid infection. We aimed to determine if orthoplastic reconstruction using mechanically relevant devitalized bone (ORDB) was associated with an increased infection rate in type IIIB open tibial shaft fractures.

Aims

We aimed to evaluate the health-related quality of life (HRQoL) in children with supracondylar humeral fractures (SCHFs), who were treated following the recommendations of the Paediatric Comprehensive AO Classification, and to assess if HRQoL was associated with AO fracture classification, or fixation with a lateral external fixator compared with closed reduction and percutaneous pinning (CRPP).

Aims

Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity.

Aims

Little is known about the effect of haemorrhagic shock and resuscitation on fracture healing. This study used a rabbit model with a femoral osteotomy and fixation to examine this relationship.

Aims

Recent studies of nonoperatively treated displaced midshaft clavicular fractures have shown a high incidence of nonunion and unsatisfactory functional outcome. Some studies have shown superior functional results and higher rates of healing following operative treatment. The aim of this study was to compare the outcome in these patients after nonoperative management with those treated with fixation.

Aims

The primary aim of this study was to determine if delayed clavicular fixation results in a greater risk of operative complications and revision surgery.

Aims

The aim of this study was to examine the results of the acetabular distraction technique in achieving implantation of a stable construct, obtaining biological fixation, and producing healing of chronic pelvic discontinuity at revision total hip arthroplasty.

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.

Aims

The modified Dunn procedure has the potential to restore the anatomy in hips with severe slipped capital femoral epiphyses (SCFE). However, there is a risk of developing avascular necrosis of the femoral head (AVN). In this paper, we report on clinical outcome, radiological outcome, AVN rate and complications, and the cumulative survivorship at long-term follow-up in patients undergoing the modified Dunn procedure for severe SCFE.

Aims

The crucial role of the radial head in the stability of the elbow in terrible triad injury is acknowledged. This retrospective study aims to compare the results of resection of a severely comminuted radial head with or without prosthetic arthroplasty as part of the reconstruction for this injury.

This animal study compares different methods of performing an osteotomy, including using an Erbium-doped Yttrium Aluminum Garnet laser, histologically, radiologically and biomechanically. A total of 24 New Zealand rabbits were divided into four groups (Group I: multihole-drilling; Group II: Gigli saw; Group III: electrical saw blade and Group IV: laser). A proximal transverse diaphyseal osteotomy was performed on the right tibias of the rabbits after the application of a circular external fixator. The rabbits were killed six weeks after the procedure, the operated tibias were resected and radiographs taken.

The specimens were tested biomechanically using three-point bending forces, and four tibias from each group were examined histologically. Outcome parameters were the biomechanical stability of the tibias as assessed by the failure to load and radiographic and histological examination of the osteotomy site.

The osteotomies healed in all specimens both radiographically and histologically. The differences in the mean radiographic (p = 0.568) and histological (p = 0.71) scores, and in the mean failure loads (p = 0.180) were not statistically significant between the groups.

Different methods of performing an osteotomy give similar quality of union. The laser osteotomy, which is not widely used in orthopaedics is an alternative to the current methods.

Cite this article: Bone Joint J 2015;97-B:1628–33.

Aims

The management of a significant bony defect following excision of a diaphyseal atrophic femoral nonunion remains a challenge. We present the outcomes using a combined technique of acute femoral shortening, stabilized with a long retrograde intramedullary nail, accompanied by bifocal osteotomy compression and distraction osteogenesis with a temporary monolateral fixator.

Aims

The primary aim of this study was to determine the morbidity of a tibial strut autograft and characterize the rate of bony union following its use.