Aims

The mobile bearing Oxford unicompartmental knee arthroplasty (OUKA) is recommended to be performed with the leg in the hanging leg (HL) position, and the thigh placed in a stirrup. This comparative cadaveric study assesses implant positioning and intraoperative kinematics of OUKA implanted either in the HL position or in the supine leg (SL) position.

We performed limb lengthening and correction of deformity of nine long bones of the lower limb in six children (mean age, 14.7 years) with osteogenesis imperfecta (OI). All had femoral lengthening and three also had ipsilateral tibial lengthening. Angular deformities were corrected simultaneously. Five limb segments were treated using a monolateral external fixator and four with the Ilizarov frame. In three children, lengthening was done over previously inserted femoral intramedullary rods. The mean lengthening achieved was 6.26 cm (mean healing index, 33.25 days/cm). Significant complications included one deep infection, one fracture of the femur and one anterior angulation deformity of the tibia. The abnormal bone of OI tolerated the external fixators throughout the period of lengthening without any episodes of migration of wires or pins through the soft bone. The regenerate bone formed within the time which is normally expected in limb-lengthening procedures performed for other conditions. We conclude that despite the abnormal bone characteristics, distraction osteogenesis to correct limb-length discrepancy and angular deformity can be performed safely in children with OI

Osteotomies are commonly carried out in orthopaedic surgery, particularly in limb reconstruction. Complications are uncommon provided that sufficient care is taken and a sound technique used. We describe three cases of formation of false aneurysm after osteotomy, with acute, delayed and asymptomatic onset. The diagnosis was supported by ultrasound investigation, and confirmed by angiography. Embolisation with coils was a successful method of treatment. We recommend a safe method of osteotomy with good bone exposure and adequate soft-tissue protection

Objectives. The biomembrane (induced membrane) formed around polymethylmethacrylate (PMMA) spacers has value in clinical applications for bone defect reconstruction. Few studies have evaluated its cellular, molecular or stem cell features. Our objective was to characterise induced membrane morphology, molecular features and osteogenic stem cell characteristics. Methods. Following Institutional Review Board approval, biomembrane specimens were obtained from 12 patient surgeries for management of segmental bony defects (mean patient age 40.7 years, standard deviation 14.4). Biomembranes from nine tibias and three femurs were processed for morphologic, molecular or stem cell analyses. Gene expression was determined using the Affymetrix GeneChip Operating Software (GCOS). Molecular analyses compared biomembrane gene expression patterns with a mineralising osteoblast culture, and gene expression in specimens with longer spacer duration (> 12 weeks) with specimens with shorter durations. Statistical analyses used the unpaired student t-test (two tailed; p < 0.05 was considered significant). Results. Average PMMA spacer in vivo time was 11.9 weeks (six to 18). Trabecular bone was present in 33.3% of the biomembrane specimens; bone presence did not correlate with spacer duration. Biomembrane morphology showed high vascularity and collagen content and positive staining for the key bone forming regulators, bone morphogenetic protein 2 (BMP2) and runt-related transcription factor 2 (RUNX2). Positive differentiation of cultured biomembrane cells for osteogenesis was found in cells from patients with PMMA present for six to 17 weeks. Stem cell differentiation showed greater variability in pluripotency for osteogenic potential (70.0%) compared with chondrogenic or adipogenic potentials (100% and 90.0%, respectively). Significant upregulation of BMP2 and 6, numerous collagens, and bone gla protein was present in biomembrane compared with the cultured cell line. Biomembranes with longer resident PMMA spacer duration (vs those with shorter residence) showed significant upregulation of bone-related, stem cell, and vascular-related genes. Conclusion. The biomembrane technique is gaining favour in the management of complicated bone defects. Novel data on biological mechanisms provide improved understanding of the biomembrane’s osteogenic potential and molecular properties. Cite this article: Dr H. E. Gruber. Osteogenic, stem cell and molecular characterisation of the human induced membrane from extremity bone defects. Bone Joint Res 2016;5:106–115. DOI: 10.1302/2046-3758.54.2000483

Aims

While a centralized system for the care of patients with a sarcoma has been advocated for decades, regional variations in survival remain unclear. The aim of this study was to investigate regional variations in survival and the impact of national policies in patients with a soft-tissue sarcoma (STS) in the UK.

Aims

While mechanical alignment (MA) is the traditional technique in total knee arthroplasty (TKA), its potential for altering constitutional alignment remains poorly understood. This study aimed to quantify unintentional changes to constitutional coronal alignment and joint line obliquity (JLO) resulting from MA.

We treated 50 patients with bony malignancy by en-bloc resection, extracorporeal irradiation with 50 Gy and re-implantation of the bone segment. The mean survivor follow-up was 38 months (12 to 92) when 42 patients were alive and without disease. There were four recurrences. The functional results were good according to the Mankin score (17 excellent, 13 good, nine fair, three failures), the Musculoskeletal Tumour Society score (mean 77) and the Toronto Extremity Salvage score (mean 81). There was solid union, but bone resorption was seen in some cases. The dose of radiation was lethal to all cells and produced a dead autograft of perfect fit. Extracorporeal irradiation is a useful technique for limb salvage when there is reasonable residual bone stock. It allows effective re-attachment of tendons and produces a lasting biological reconstruction. There should be no risk of local recurrence or of radiotherapy-induced malignancy in the replanted bone

We describe two siblings with congenital growth defects of the distal limb bones and their progress over four years. They bear some resemblances to a boy described in 1958 by Solonen and Sulamaa and to a father and his three sons described in 1944 by Nievergelt

We report the results of distraction osteogenesis (callotasis) for the reconstruction of extensive defects after the excision of skeletal tumours in the limbs. Bone transport was performed in ten patients (five osteosarcomas and five giant-cell tumours), shortening-distraction in three (two osteosarcomas and one Ewing’s sarcoma), and distraction osteogenesis combined with an intramedullary nail to reduce the time of external fixation in six (three osteosarcomas, two chondro-sarcomas, and one malignant fibrous histiocytoma). The mean length of the defects after excision of the lesion was 8.4 cm. The mean external fixation index was 39.5 days/cm for the group treated by bone transport, 34.1 days/cm for the shortening-distraction group, and 24.0 days/cm for the group treated by distraction and an intramedullary nail. Functional evaluation gave excellent results in 12 patients, good in five and fair in two. There were ten complications in 19 patients, all of which were successfully treated. We also classified reconstruction using distraction osteogenesis into five types based on the location of the defects after resection of the tumour: type 1, diaphyseal; type 2, metaphyseal; type 3, epiphyseal; type 4, subarticular reconstruction; and type 5, arthrodesis. Our results suggest that reconstruction using distraction osteogenesis provides bone which will develop sufficient biomechanical strength and durability. It is beneficial in patients with an expectation of long-term survival and in growing children

Aims

Myxofibrosarcomas (MFSs) are malignant soft-tissue sarcomas characteristically presenting as painless slowly growing masses in the extremities. Locally infiltrative growth means that the risk of local recurrence is high. We reviewed our experience to make recommendations about resection strategies and the role of the multidisciplinary team in the management of these tumours.

We studied the quantity and rate of formation of new bone during lengthening of 17 limb segments in 10 patients using dual-energy X-ray absorptiometry (DEXA), ultrasonography and radiography. Whereas new bone was detected by both DEXA and ultrasonography within 1 to 2 weeks of distraction, it was not visible on the radiographs until 4 to 8 weeks. Limb alignment and gap measurement were accurately assessed by DEXA without the need for standard radiographs or scanograms. With ultrasound the distraction gap appeared as an echolucent window which narrowed progressively producing a hyper-reflecting line after which further consolidation could not be assessed. As measured by DEXA the density of the new bone at this stage was approximately 45% of control values and did not represent normal cortication. Whereas ultrasound could be used to identify defects in mineralisation and to determine when to dynamise the fixator system, DEXA could measure the quantity and rate of formation of bone throughout lengthening

1. A quantitative study of phosphatase distribution in the limb bones of growing rabbits is reported. 2. Alkaline phosphatase is present in high concentrations in areas of deposition of new bone. Both local concentrations and the total alkaline phosphatase content of a bone are found to decrease with age. There is good correlation between total alkaline phosphatase activity and monthly increment of weight. 3. Acid phosphatase is present in these bones in greatly less concentrations than alkaline phosphatase. 4. The acid phosphatase of bone shows nearly full activity in the presence of 0·5 per cent formaldehyde. It can be subdivided into two enzymes with characteristically different distributions by the effect of M/100 tartrate on activity. 5. The formaldehyde-stable and tartrate-stable acid phosphatase of rabbit bone (FTS) has a distribution very similar to that of alkaline phosphatase, though very much less in amount, and, like the latter, declines in activity as the bone matures. 6. Tartrate-inhibited, formaldehyde-stable acid phosphatase (FSTI) is found mainly in red marrow and cancellous bone, and full activity persists in mature bone. This enzyme may be associated with resorption and remodelling of bone, or it may represent residual activity under these conditions of the acid phosphatase of developing erythrocytes in the marrow

Aims

We analyzed the long-term outcomes of patients observed over ten years after resection en bloc and reconstruction with extracorporeal irradiated autografts

Peripheral limb ischaemia is rare in children. We have treated only 12 infants and children with this condition in the past 15 years at the Royal Hospital for Sick Children in Glasgow. There were nine neonates and three older children. Most were suffering from life-threatening illnesses or severe infection. Two were born with ischaemic arms with no apparent cause. We have analysed the factors leading to ischaemia, the outcome of the initial treatment and the later orthopaedic problems. Two required amputation of both legs, one of an arm, two of feet and one of toes. Two had skin grafts. All surgery was performed after demarcation was well established and delayed closure was used after amputation. Five children developed limb-length discrepancy or an angular deformity. To date two have required additional corrective surgery

Limb lengthening is used to correct leg length discrepancy and to increase stature. The reported frequency of peripheral nerve complications varies from 5% to 30%, but is probably underestimated. Damage may be direct or be caused by overstretching of the nerves. We have used electrophysiological tests to evaluate five patients during bilateral tibial lengthening by the Ilizarov method. Results after 24 to 107 days of lengthening showed electromyographic evidence of partial muscle denervation in all 10 limbs, with reduced motor conduction velocities in two tibial nerves and three common peroneal nerves. The sensory conduction velocity in the sural nerve was always unchanged. A clear relationship was shown between the amount of tibial lengthening and the degree of electrophysiological abnormality. Our results suggest that subclinical nerve damage is a very frequent complication of tibial lengthening

We undertook a retrospective analysis of 306 procedures on 233 patients, with a mean age of 12 years (1 to 21), in order to evaluate the use of somatosensory evoked potential (SSEP) monitoring for the early detection of nerve compromise during external fixation procedures for limb lengthening and correction of deformity. Significant SSEP changes were identified during 58 procedures (19%). In 32 instances (10.5%) the changes were transient, and resolved once the surgical cause had been removed. The remaining 26 (8.5%) were analysed in two groups, depending on whether or not corrective action had been performed in response to critical changes in the SSEP recordings. In 16 cases in which no corrective action was taken, 13 (81.2%, 4.2% overall) developed a post-operative neurological deficit, six of which were permanent and seven temporary, persisting for five to 18 months. In the ten procedures in which corrective action was taken, four patients (40%, 1.3% overall) had a temporary (one to eight months) post-operative neuropathy and six had no deficit. After appropriate intervention in response to SSEP changes, the incidence and severity of neurological deficits were significantly reduced, with no cases of permanent neuropathy. SSEP monitoring showed 100% sensitivity and 91% specificity for the detection of nerve injury during external fixation. It is an excellent diagnostic technique for identifying nerve lesions when they are still highly reversible.

We describe a technique for slow, progressive, symmetrical distraction of the growth plate using a lightweight dynamic axial fixation system. Results are given for the elongation of 40 bony segments in children with limb-length discrepancies and 60 segments in children with achondroplasia or hypochondroplasia. Increases in limb length of up to 36% were obtained in non-achondroplastic and up to 64.5% in achondroplastic patients. There were no nerve or vascular lesions or bony infections and no case required a bone graft. Pin-track complications occurred in only 1.5%

We report the results of limb salvage for non-metastatic osteosarcoma of the distal tibia using resection arthrodesis, autogenous fibular graft and fixation by an Ilizarov external fixator. In six patients with primary osteosarcoma of the distal tibia who refused amputation, treatment with wide en bloc resection and tibiotalar arthrodesis was undertaken. The defect was reconstructed using non-vascularised free autogenous fibular strut graft in three patients and a vascularised pedicular fibular graft in three, all supplemented with iliac cancellous graft at the graft-host junction. An Ilizarov external fixator was used for stabilisation of the reconstruction. In five patients sound fusion occurred at a mean of 13.2 months (8 to 20) with no evidence of local recurrence or deep infection at final follow-up. The mean post-operative functional score was 70% (63% to 73%) according to the Musculoskeletal Tumour Society scoring system. All five patients showed graft hypertrophy. Union of the graft was faster in cases reconstructed by vascularised fibular grafts. One patient who had a poor response to pre-operative chemotherapy developed local tumour recurrence at one year post-operatively and required subsequent amputation

Until recently the accepted treatment of choice for severe type-II fibular hemimelia has been Syme’s or Boyd’s amputation. The alternative of distraction lengthening using the Ilizarov technique is now available. We report three patients (four limbs) with type-II fibular hemimelia who were treated by the Ilizarov technique and followed up for two to six years. Severe progressive procurvatum and valgus deformity of the tibia and valgus deformity and lateral subluxation of the ankle were found in all four limbs. Multiple additional soft-tissue and bony surgery was necessary. In view of these problems we feel that reappraisal of the indications for lengthening in type-II fibular hemimelia is necessary

We have compared, in rabbits, two techniques of limb lengthening by distraction of the epiphyseal plate using a unilateral external fixation frame. In all cases, 14 mm of symmetrical lengthening without deviation was achieved. With rapid distraction at rates of 1 mm per day (distractional epiphyseolysis) separation of the epiphysis from the metaphysis occurred by day 7, and by day 70 almost complete ossification of the cartilage and the elongated segment was evident. In contrast, slow distraction at 0.25 mm every 12 hours (chondrodiatasis) produced hyperplasia of growth cartilage without any evidence of detachment at 28 days, the end of the distraction period. By day 70 the epiphyseal plate had returned to normal thickness with normal cellular morphology, while the lengthened segment was occupied by ossified tissue. The significance of these findings is discussed