MRI study of the cruciate ligaments and menisco-femoral ligaments of the knee.

PURPOSE: It has been argued that the meniscus-femoral ligaments disappear with age. We therefore analyzed the presence of the meniscus-femoral ligaments, in MRI. MATERIALS AND METHODS: We measured the PCL, ACL and MFL, noting their presence or absence in 120 Knee MRIs, 51 in women and 69 in men. All knees underwent MRI in the coronal, sagittal and axial planes. T1 and T2 weighted sequences were obtained. A descriptive statistical study of all the variables was carried out, and a comparative study was performed between sexes, sides and age groups. RESULTS: The MFLp was more frequent, found in 67 (55.8%) cases, than the MFLa, in 36 (30%) cases, and both together were present in 27 (22.5%) knees. We found a strong correlation between ACL length and PCL length (p = 0.001), we found no correlation between the presence of the posterior MFL either with age (p = 0.307) or with sex (p = 0.779) or side (p = 0.733). We also found no relationship between the presence of the anterior MFL and age (p = 0.553), or sex (p = 0.913), or laterality (p = 0.082). CONCLUSION: We found a strong correlation between ACL length and PCL length. In our study, the presence of the posterior MFL was more frequent, being present in 55.68%, while the anterior MFL was found in 30% of the knees. We did not observe that the presence of LMF decreases with age.

Two-stage bone and meniscus allograft and autologous chondrocytes implant for unicompartmental osteoarthritis: midterm results.

BACKGROUND: We analyzed the clinical and radiographic evolution of patients with knee unicompartmental osteoarthritis and axis alteration and osteochondral lesions in the femoral condyle, treated with tibial plateau and meniscus allograft and cultured autologous chondrocyte implantation in the femur in two steps. PURPOSE: To analyze the clinical results with the first patients treated with this two-stage technique to avoid knee prosthesis in patients with unicompartmental osteoarthritis. MATERIAL AND METHODOLOGY: Sixteen patients, average age 56 years, were included in a cohort study. We performed an osteotomy with tibia plateau allograft, including the meniscus. In a second surgery, the chondrocyte fibrin scaffold was placed in the femur. Clinical symptoms and function were measured using KSSR and KOOS scores. Wilcoxon's test was performed to compare the results over the 2-year follow-up period. RESULTS: Mean KSSR before surgery was 35.69 (SD: 3.75) points, rising to 67 (SD: 15.42) at 3 months, 95.88 at 12 months (SD: 2.68) and 96.31 at 24 months (SD: 2.24). The KOOS before surgery was 65.14 (SD: 16.34), rising to 72.68 after 3 months (SD: 19.15), 76.68 at 12 months (SD: 18.92) and 64.28 at 24 months (SD: 11.79). Four of 5 patients returned to engaging in the activity that they had stopped practicing. Three patients experienced collapse of the tibia allograft, and they needed later a prosthesis. CONCLUSIONS: Simultaneous tibia plateau allograft and autologous chondrocyte implantation in the femur, after correction of the angular deformity, were performed, restoring the anatomy of the medial compartment and knee function in 82% of the patients 2 years after the operation. LEVEL OF EVIDENCE: IV.

Resultados clínicos del tratamiento de la metatarsalgia mecánica sin afectación del primer metatarsiano / Clinical results of treatment of mechanical metatarsalgia without first metatarsal involvement

Resumen: Objetivo: Analizar los resultados clínicos de las metatarsalgias tratadas con osteotomías metafisarias metatarsales distales (DMMO) por vía percutánea. Material y métodos: Estudio prospectivo y continuo de 29 pacientes afectados de metatarsalgia mecánica aislada unilateral, intervenidas con una DMMO, con un seguimiento medio de 38 meses. La edad media de los pacientes fue 58 (rango: 50-67) años y sólo dos hombres. Utilizamos la escala AOFAS, anotamos la fórmula digital y metatarsiana sobre la radiografía. Registramos la valoración subjetiva del cirujano y del paciente al final del tratamiento. Resultados: La mejoría de la puntuación final superó los 80 puntos en todos los metatarsianos (p = 0.000), con una mejoría significativa del dolor (p = 0.000) y de las callosidades (p = 0.000), mejorando la estabilidad articular metatarso-falángica e interfalángica y la alineación de los metatarsianos. El tipo del calzado no cambió después de la cirugía, no encontramos variación de la movilidad, ni en las articulaciones metatarso-falángicas (p = 0.382), ni en las interfalángicas (p = 0.672). Después de la cirugía aumentaron los pies cuadrados (p = 0.027). La fórmula metatarsiana sufrió pocas modificaciones, 96% de los pacientes y de los cirujanos se mostraron «muy satisfechos¼ o «satisfechos¼. Conclusión: La DMMO consigue un alto grado de satisfacción en pacientes y también en el cirujano, elimina el dolor y la hiperqueratosis bajo la cabeza de los metatarsianos dolorosos que mejora significativamente la capacidad funcional de los pacientes.

Abstract: Objective: To analyze the clinical results of metatarsalgia treated with percutaneous distal metatarsal metaphyseal osteotomies (DMMO). Material and methods: Prospective and continuous study of 29 patients with isolated unilateral mechanical metatarsalgia, operated on with DMMO, with a mean follow-up of 38 months. The mean age of the patients was 58 (range: 50-67) years and only two men. We use the AOFAS score, we obtained the digital and metatarsal formulas on the X-rays. We record the subjective assessment of the surgeon and the patient at the end of the treatment. Results: The improvement in the final score exceeded 80 points in all cases (p = 0.000), with a significant improvement in pain (p = 0.000) and calluses (p = 0.000), improving metatarsal-phalangeal joint stability and interphalangeal and metatarsal alignment. The type of footwear did not change after surgery, we found no variation in mobility, neither in the metatarsophalangeal joints (p = 0.382), nor in the interphalangeal joints (p = 0.672). After surgery increased the square foot morphology (p = 0.027) but the metatarsal formula underwent few modifications. Patients and surgeons were in 96% of the cases «very satisfied¼ or «satisfied¼. Conclusion: DMMO achieves a high degree of satisfaction in patients and in the surgeon, pain and hyperkeratosis under the head of the painful metatarsals disappear and that significantly improves the functional capacity of patients.

[Clinical results of treatment of mechanical metatarsalgia without first metatarsal involvement]. / Resultados clínicos del tratamiento de la metatarsalgia mecánica sin afectación del primer metatarsiano.

OBJECTIVE: To analyze the clinical results of metatarsalgia treated with percutaneous distal metatarsal metaphyseal osteotomies (DMMO). MATERIAL AND METHODS: Prospective and continuous study of 29 patients with isolated unilateral mechanical metatarsalgia, operated on with DMMO, with a mean follow-up of 38 months. The mean age of the patients was 58 (range: 50-67) years and only two men. We use the AOFAS score, we obtained the digital and metatarsal formulas on the X-rays. We record the subjective assessment of the surgeon and the patient at the end of the treatment. RESULTS: The improvement in the final score exceeded 80 points in all cases (p = 0.000), with a significant improvement in pain (p = 0.000) and calluses (p = 0.000), improving metatarsal-phalangeal joint stability and interphalangeal and metatarsal alignment. The type of footwear did not change after surgery, we found no variation in mobility, neither in the metatarsophalangeal joints (p = 0.382), nor in the interphalangeal joints (p = 0.672). After surgery increased the square foot morphology (p = 0.027) but the metatarsal formula underwent few modifications. Patients and surgeons were in 96% of the cases "very satisfied" or "satisfied". CONCLUSION: DMMO achieves a high degree of satisfaction in patients and in the surgeon, pain and hyperkeratosis under the head of the painful metatarsals disappear and that significantly improves the functional capacity of patients.

OBJETIVO: Analizar los resultados clínicos de las metatarsalgias tratadas con osteotomías metafisarias metatarsales distales (DMMO) por vía percutánea. MATERIAL Y MÉTODOS: Estudio prospectivo y continuo de 29 pacientes afectados de metatarsalgia mecánica aislada unilateral, intervenidas con una DMMO, con un seguimiento medio de 38 meses. La edad media de los pacientes fue 58 (rango: 50-67) años y sólo dos hombres. Utilizamos la escala AOFAS, anotamos la fórmula digital y metatarsiana sobre la radiografía. Registramos la valoración subjetiva del cirujano y del paciente al final del tratamiento. RESULTADOS: La mejoría de la puntuación final superó los 80 puntos en todos los metatarsianos (p = 0.000), con una mejoría significativa del dolor (p = 0.000) y de las callosidades (p = 0.000), mejorando la estabilidad articular metatarso-falángica e interfalángica y la alineación de los metatarsianos. El tipo del calzado no cambió después de la cirugía, no encontramos variación de la movilidad, ni en las articulaciones metatarso-falángicas (p = 0.382), ni en las interfalángicas (p = 0.672). Después de la cirugía aumentaron los pies cuadrados (p = 0.027). La fórmula metatarsiana sufrió pocas modificaciones, 96% de los pacientes y de los cirujanos se mostraron "muy satisfechos" o "satisfechos". CONCLUSIÓN: La DMMO consigue un alto grado de satisfacción en pacientes y también en el cirujano, elimina el dolor y la hiperqueratosis bajo la cabeza de los metatarsianos dolorosos que mejora significativamente la capacidad funcional de los pacientes.

Citoquinas proinflamatorias en la grasa articular y subcutánea del muslo en pacientes artrósicos / Pro-inflammatory cytokines in the knee fat pad and subcutaneous fat of the thigh in osteoarthritic patients

Resumen: Objetivo: Analizar el nivel de citoquinas proinflamatorias en la grasa articular del paquete adiposo en pacientes con gonartrosis, en relación con la grasa subcutánea del muslo. Material y métodos: Efectuamos un estudio de grasa del paquete adiposo articular de la rodilla afectada de artrosis y de la grasa subcutánea del muslo del mismo lado, a la mayor distancia de la articulación en seis pacientes con gonartrosis grave, con una edad media de 68 años (rango: 55-81 años). De las muestras de grasa se obtuvieron las células mesenquimales progenitoras. Los sobrenadantes de células mesenquimales obtenidas se utilizaron para analizar factores inflamatorios (IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13, IL15) y angiogénicos (VEGF, PDGF bb), así como citoquinas inmunomoduladoras (IP-10 e INF-γ) y se compararon las medias de dos muestras. Resultados: El análisis cuantitativo reveló una disminución significativa (p < 0.05) de IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13 y un aumento de IL15 en la grasa de Hoffa frente al tejido adiposo subcutáneo. Del mismo modo, el análisis de factores angiógenicos como VEGF y PDGF bb, al igual que los factores IP-10 e INF-γ presentaron una disminución significativa en la grasa de Hoffa (p < 0.05) frente al tejido adiposo subcutáneo. Discusión: Las células mesenquimales del paquete adiposo articular de la rodilla artrósica grave muestran una disminución significativa de citoquinas inflamatorias, aun en el estado crónico, y una disminución significativa de factores angiogénicos y citoquinas inmunomoduladoras (IP10 e INF).

Abstract: Objective: To analyze the level of pro-inflammatory cytokines in osteoarthritis knee joint fat pad in relation to the subcutaneous fat of the thigh. Material and methods: We performed a study of fat of the knee joint adipose affected of osteoarthritis and subcutaneous fat of the thigh of the same side to the greater distance of the joint in six patients with severe gonarthrosis, with a mean age of 68 years (range: 55-81 years). From the fat samples the progenitor mesenchymal cells were obtained. The supernatants of mesenchymal cells obtained to analyze inflammatory factors (IL-1b, IL6, IL9, IL1ra, IL12, IL13, IL15) and angiogenic (VEGF, PDGF bb) and immunomodulatory cytokines (IP-10 and INF-γ) means of two samples. Results: Quantitative analysis revealed a significant (p < 0.05) decrease in IL-1b, IL6, IL8, IL9, IL1ra, IL12, IL13 and increase of IL15 in Hoffa fat pad versus subcutaneous adipose tissue. Likewise, the analysis of angiogenic factors such as VEGF and PDGF, as well as factors IP-10 and INF-γ presented a significant decrease (p < 0.05) in Hoffa fat pad versus subcutaneous adipose tissue. Discussion: Mesenchymal cells from the adipose tissue of the severe osteoarthritic knee show a significant decrease in inflammatory cytokines even in the chronic state and a significant decrease in angiogenic factors and immunomodulatory cytokines (IP10 and INF).

[Experimental induction of Perthes disease in lambs]. / Inducción experimental de la enfermedad de Perthes en corderos.

OBJECTIVE: To establish a simple, reproducible and safe experimental model, for the development of ischemic vascular necrosis of the hip in the lamb. MATERIAL AND METHODS: We used 15 lambs (10 males and 5 females) aged four weeks, divided into a control group (7 animals) and an experimental group (8 animals) producing ischemia in the proximal femur. Standard radiography and MRI were performed. The animals were euthanised at the 4th, 8th and 12th weeks after surgery. The femoral heads were extracted and measured and a histological analysis was performed with hematoxylin-eosin staining. RESULTS: Decreased height and increased width of the femoral head was observed in the X-Rays, particularly after the 4th week. We did not observe any changes in the height of the lateral pillar or trochanteric distance. The experimental group showed macroscopical hypertrophy and progressive flattening of the head. At 4 weeks necrotic areas in articular cartilage were observed, bone marrow was dense and the growth cartilage height was lower. The vessels were thickened by proliferation of the medial and adventitia layers. At 8 weeks, we found fibrosis in the subchondral bone with thinned and devitalized angiogenesis fat areas. The articular cartilage showed irregularities. At 12 weeks the closure of the physis was noted, as well as chondral areas in the trabecular bone and fat cells in the methaphysis. CONCLUSION: Although the histological changes are consistent with necrosis of the femoral head, the images obtained did not resemble Perthes disease, so we do not advise this experimental model for the study of this disease.

[Influence of the physiological medium on the mechanical properties of bone cement: can current studies be extrapolated?]. / Influencia del medio fisiológico sobre las propiedades mecánicas del cemento óseo. ¿Son los estudios actuales extrapolables?

PURPOSE: The use of bone cement is widespread in orthopaedic surgery. Most of the mechanical tests are performed in dry medium, making it difficult to extrapolate the results. The objective of this study is to assess if the mechanical properties of polymethylmethacrylate (PMMA), obtained in previous reports, are still present in a liquid medium. MATERIAL AND METHOD: An experimental study was designed with antibiotic (vancomycin) loaded PMMA. Four groups were defined according to the medium (dry or liquid) and the pre-conditioning in liquid medium (one week or one month). Wear and flexural strength tests were performed according to ASTM and ISO standards. Volumetric wear, friction coefficient, tensile strength, and Young's modulus were analyzed. All samples were examined by scanning electron microscopy. RESULTS: The samples tested in liquid medium showed lower wear and flexural strength values (P<.05). The kind of wear was modified from abrasive to adhesive in those samples studied in liquid medium. The samples with a pre-conditioning time showed lower values of wear (P<.05). CONCLUSIONS: Caution is recommended when extrapolating the results of previous PMMA results. The different mechanical strength of the cement in a liquid medium, observed in saline medium, is much closer to the clinical situation.

Trabecular metal screw implanted for avascular necrosis of the femoral head may complicate subsequent arthroplasty surgery.

A trabecular metal screw has been suggested to treat avascular osteonecrosis of the femoral head. Non-surgical management with partial weight bearing can only be selected for early stages and very small lesions. Even in such cases, it has been proven to be ineffective in 80-90 % of patients. Conversely, the results with trabecular metal implants are not always clinically satisfactory, and some patients can show emerging pain and activity limitations that could require conversion to a total hip arthroplasty. Hereby we report the results of 6 patients who underwent this implant and describe the histopathology of the bone at the femoral neck and to speculate on the causes of complications encountered during arthroplasty surgery. The necrosis was stopped in 1 case, and 5 hips showed disease progression. Two protrusions of the screw apex were observed. In one case, rupture of the greater trochanter during prosthesis implant occurred. After trabecular metal implants for avascular osteonecrosis, some patients can require conversion to a total hip arthroplasty. Two patients had an intraoperative fracture with detachment of the greater trochanter that required wiring. Complications related to implant removal can be encountered, and the orthopedic surgeon should be aware of removal techniques.

[SECOT consensus on painful knee replacement]. / Consenso SECOT sobre artroplastia de rodilla dolorosa.

The opinions of 21 experts in knee surgery were evaluated in this study, using a DELPHI questionnaire method in two successive rounds, on 64 controversial scenarios that covered both the diagnosis and possible treatment of painful knee replacements. The level of consensus was significantly unanimous in 42 items and of the design in 5, with no agreement in 17 of the questions presented. light of the published scientific evidence, the surgeons who took part showed to have a notable level of information on the most effective diagnostic tests, although, it should be pointed out that there was a lack of confidence in the possibility of ruling out an infection when the erythrocyte sedimentation rate and the C-reactive protein were within normal values, which have been demonstrated in the literature to have a high negative predictive value As regards the treatments to employ in the different situations, the responses of the expert panel were mainly in agreement with the data in the literature. The conclusions of this consensus may help other surgeons when they are faced with a painful knee prosthesis.

Primary cancellous bone formation with BMP and micro-chambered beads: experimental study on sheep.

PROBLEM: The physiological reconstruction of cancellous bone defects in surgery of the locomotor system is an unsatisfactorily solved problem. AIMS: The aims of this study are to examine whether micro-chambered ß-tricalcium-phosphate (ß-TCP) beads provide a certain capillary force suctioning in blood and bone marrow thus forming a stable "negative"-replica of the bone marrow spaces. If so, a new approach for osteoconduction would yield primarily a scaffold of lamellar cancellous bone under load without a long-lasting remodeling process. Recombinant human bone morphogenetic protein (rhBMP) might even enhance all processes of defect healing, remodeling and ß-TCP resorption; gentamicin-loaded ε-caprolactone might protect the implant. MATERIAL AND METHODS: Ten sheep were operated on; the patella-groove model and the tibial head were used. A defect of 9.4 × 20 mm was created using wet-grinding-diamond instruments. Micro-chambered ß-TCP-beads of 4-6 mm with 0.35 mg rhBMP-7 + 0.1 g collagen per animal, or 1.5 g demineralized bone matrix (DBM) paste on the contra-lateral side were implanted. Both osteoinduction groups were compared with the defect in the tibial heads where plain micro-chambered ceramic beads were inserted. Added to the beads was 12.5 mg gentamicin sulphate in 12.5 mg ε-caprolactone-carrier. Outward diffusion was prevented using a 1-mm-thick press-fit inserted ceramic lid. The bone healing, remodeling and resorption of the ceramic in a right-left comparison of the patella groove and the tibial head was examined at 6 weeks, 2 and 3 months; one animal in reserve was followed for 14 months. The animals were perfusion-fixed, the vasculature micro-casted with an acrylate and nondemineralized processed, and with µ-CT and microscopically documented. RESULTS: A primary load-bearing spongiosa had developed around the beads, which shortened the remodeling process. The strong micro-chambered, resorbable ß-TCP-beads demonstrate high capillary strength, resorb blood and bone marrow, and represent a stable formative material which, as a carrier for the controlled local release of BMP, that accelerates bone healing, shortens resorption and remodeling compared with plain and DBM loaded implants. CONCLUSION: Micro-chambered beads represent the bone-forming element, BMP yields a fast defect healing and enhanced remodeling of bone and resorption of ß-TCP compared to delayed and incomplete reconstruction and resorption of ß-TCP on the DBM-side, the plain implants reached nearly the same reconstruction, but far later compared with the BMP loaded implants.

Consequences of intra-articular bleeding in haemophilia: science to clinical practice and beyond.

Blood in the joint causes a number of physiological and pathological events that eventually lead to haemophilic arthropathy. Animal models show that blood in the joint induces inflammation that continues long after blood has been cleared. TNF-alpha, IL-1 beta and IL-6 are inflammatory mediators that increase following haemarthrosis in haemophilic mice. Conventional anti-inflammatory drugs have failed to demonstrate a lasting effect in preventing haemophilic arthropathy. A new TNF-alpha antagonist has shown promising results in haemophilic mice. Similarly, the use of cyclo-oxygenase-2 inhibitors may reduce angiogenesis associated with the healing process following bleeding and the associated tissue damage. Animal models are useful for studying the pathophysiology of haemarthropathy, however, when applying results from animals to humans, the differences in matrix turnover rate, thickness of cartilage and joint biomechanics must be kept in mind. In people with haemophilia, there is a variable response to haemarthrosis as demonstrated by magnetic resonance imaging (MRI). Up to 30% of subjects have normal MRI despite having three or more haemarthroses into the same joint. Once bone damage is present, little can be done to restore anatomic integrity. Several molecules, including members of the bone morphogenic protein subfamily, have been injected into bone defects in non-haemophilic subjects with some evidence of benefit. To achieve the primary goal of reducing blood in the joint and the negative sequelae, it is questionable to use ice to treat haemarthrosis. Indeed low temperature is associated with impairment of coagulation enzyme activity and platelet function.

[Bone-tendon integration of autologous grafts using different diameter tunnels. An experimental study on sheep]. / Integración tendinosa de plastias autólogas en túneles de diferente calibre. Estudio experimental en ovejas.

OBJECTIVE: To analyse the bone-ligament integration «ligamentization¼ of the tendon graft in the reconstruction of anterior cruciate ligament (ACL) performing tunnels of different diameter. MATERIAL AND METHODS: We performed the same reconstruction procedure using an autologous tendon graft taken from the superficial tendon of the hoof in 41 adult sheep. In Group A the tibial and femoral tunnels were 5 mm in diameter and in Group B they were 7 mm in diameter. The sheep were sacrificed at 3, 6 and 12 months after the surgery. Histological studies were performed on the graft and the tunnels, as well as a biomechanical analysis of the tibial-femoral complex. RESULTS: In group A we did not observe direct integration of the bone and the tendon graft or any fibres joining both structures, although there was vascularized fibrous tissue. In group B we did not observe any direct binding of the bone and the tendon graft either, although there was abundant fibrous tissue. The tendon graft showed a fascicular structure that increased over time in order to create septa for vascular penetration. Macroscopically the ACL graft had a dense appearance, which was very similar to the original tendon graft. The tendon grafts from group B and with a longer follow up period required a higher strength to produce maximum breakage than the tendon grafts from group A. CONCLUSION: After one year follow up, the histological study shows that the tendon graft is not transformed into a ligament, and there is no integration of the tendon graft in tunnels regardless of their diameter. Therefore, fixation techniques are essential to maintain the orientation and tension of the tendon graft.

Histomorphometric study of growth plate subjected to different mechanical conditions (compression, tension and neutralization): an experimental study in lambs. Mechanical growth plate behavior.

We studied the morphologic effect of low mechanical stresses (compression, tension and neutralization) on the growth cartilage with an external fixator in 18 young lambs. On radiography, we only found more length in the femora subjected to tension (P < 0.05). Bony bridges were not present, nor were there signs of altered vascularization or Ranvier's perichondral ring. Histomorphometrically, in the group subjected to tension, the germinative layer in the femur was higher (P < 0.001) in the bones that had undergone surgery. The proliferative layer was lower in the operated tibia (P < 0.001), and the hypertrophic layer was higher in operated tibias and femora (P < 0.001). In the group subjected to compression, the germinative layer in the femora was higher in the operated bones (P < 0.05); the proliferative layer of the tibia was lower (P < 0.001) and the hypertrophic layer was higher (P < 0.001) in both operated bones. In the neutralization group, the proliferative layer of both operated bones presented lower values (P < 0.001) and the hypertrophic layer was higher (P < 0.001) than that in the control groups.

External fixation in tumour pathology.

An appraisal of the clinical records of patients with malignant bone tumours enabled us to identify 61 whom we have treated by external fixation. There were 38 males and 23 females with ages ranging from 4 to 58 years, the mean being 14 years. The average period of follow-up was 6 years (1-12 years). For the purpose of our analysis the patients were divided into three groups according to whether the fixator was fitted before, during or after tumour resection.

Distraction osteogenesis of the lower extremity with use of monolateral external fixation. A study of two hundred and sixty-one femora and tibiae.

We reviewed the results of distraction osteogenesis of 114 femora and 147 tibiae that had been lengthened to treat a variety of diagnoses. The femora had been lengthened an average of eleven centimeters (range, 3.5 to 17.0 centimeters), or 48 per cent (range, 8 to 86 per cent) of the original femoral length. The average total time for the treatment of the femora (use of the fixator and any subsequent immobilization) was 257 days (range, 105 to 420 days). There were 114 complications related to the femoral lengthenings, which led to eighty-seven additional operations. The tibiae were lengthened an average of nine centimeters (range, 3.0 to 15.6 centimeters), or 41 per cent (range, 9 to 100 per cent) of the original tibial length. The average total time for the treatment of the tibiae was 268 days (range, 110 to 497 days). There were 196 complications related to the tibial lengthenings, which led to 219 additional operations. The Achilles tendon was lengthened during or after seventy-three (50 per cent) of the tibial lengthenings. The femoral lengthenings that were performed to treat a limb-length discrepancy were associated with significantly higher rates of complications overall (p = 0.010) and additional operations (p = 0.023) for each percentage of length gained than those that were performed to treat achondroplasia or another skeletal dysplasia. The femoral lengthenings that were performed to treat short stature (of an endocrine or idiopathic etiology) were also associated with higher rates of complications overall and additional operations than those performed to treat skeletal dysplasias, but the rates were lower than those for lengthenings performed to treat limb-length discrepancy. The rate of complications overall associated with femoral lengthening in patients who were fourteen years old or more was significantly higher than that associated with lengthening in patients who were less than fourteen years old (p = 0.047). Femoral lengthening through the metaphysis was associated with significantly higher rates of complications overall (p = 0.031) and additional operations (p = 0.042) for each percentage of length gained than femoral lengthening through the diaphysis. The tibial lengthenings that were performed to treat Turner syndrome and idiopathic short stature were associated with significantly higher rates of complications overall (p = 0.026) and additional operations (p = 0.003) for each percentage of length gained than those performed to treat skeletal dysplasias. The rate of joint-related problems (p = 0.044) and that of additional operations (p = 0.053) after tibial lengthening in patients who were fourteen years old or more were significantly higher than those rates after tibial lengthening in patients who were less than fourteen years old. The site of the tibial osteotomy did not affect the rate of complications or additional operations. The femoral healing indices (in terms of both days per centimeter [p = 0.002] and days for each percentage of length gained [p = 0.019]) were significantly higher in the patients who were fourteen years old or more than in those who were less the fourteen years old. These values could not be used to predict an increase in the complications because of poor bone formation. The results of the present review suggest that the use of healing indices to gauge the final outcome of distraction osteogenesis is questionable; we were unable to discern significance or clinical importance from appropriately adjusted values.

Measurement of bone lengthening forces; an experimental model in the lamb.

OBJECTIVE: To obtain the mechanical behaviour pattern of the lengthening process. DESIGN. IN VIVO: measurement of forces during bone lengthening in lambs. BACKGROUND: A series of parameters of a mechanical and biological nature have a bearing on all lengthening processes, and most of them are not fully understood. METHODS: A strain-gauge-monitored unilateral fixator was designed and used to obtain data about the changes which took place in the forces of elongation at a rate of 1 mm/day in four lambs while a 3 cm progressive lengthening of the left tibia was being performed, analysing how these forces behaved from day to day, and how they changed in the course of a single day. RESULTS: The maximum forces in all the animals each day occur after distraction, and the forces reach their greatest magnitude between days 21 and 25 after surgery, attaining values of slightly over 8 kg (40-50% of the animal's weight). The maximum daily force starts to drop 1 h after distraction, and continues to decrease gradually throughout the day until it reaches a value slightly greater than the initial force on the previous day. CONCLUSION: This pattern is due to the distraction of soft tissues which gradually adapt to their new situation, thereby reducing the level of stress. RELEVANCE: In the daily bone lengthening procedure, the greatest forces are produced in a short period of time immediately after lengthening. they could be reduced to decrease pain in the patient and loads on the device by performing lengthening over a greater number of steps or using dynamic equipment able to absorb these forces.

Removal of metaphyseal bone tumours with preservation of the epiphysis. Physeal distraction before excision.

In immature long bones, radical excision of malignant tumours of the metaphysis may necessitate sacrifice of the adjacent epiphysis. To preserve the adjacent joint while allowing a safe margin of excision, we used physeal distraction before removing the tumour. From July 1984 to August 1992, we operated on 20 patients by this method. After a mean follow-up of 54 months there was no local recurrence in the epiphyseal region. Three patients had developed pulmonary metastases.

[Age changes of functional nuclear swelling and classes of nuclei in human hepatocytes]. / Zu Alternsveränderungen der funktionellen Kernschwellung und der Kernklassen menschlicher Hepatozyten.

The aim of the study was to describe aging changes in the functional nuclear edema and the classification of human hepatocyte nuclei, by determining three parameters--the size of the nucleus, the relative DNA quantity and the number of chromocenters. For this purpose, karyometry and DNA cytophotometry were performed on 10 human liver preparations. The data obtained was subjected to correlation, cluster and discriminance analysis. The results indicated a reduction in the capacity of liver cells for functional nuclear edema as aging progressed. Whereas at a young age there is only a loose correlation between nuclear size and DNA content, it becomes much stricter later on, partly caused by polyploidization. Cluster analysis, followed by discriminance analysis, is well suited for dividing the nuclei of human hepatocytes into two or three statistical populations provided the nuclear area, DNA quantity and number of chromocenters are all used as characteristics simultaneously. When allowance is made for functional edema, the biological interpretation of clusters from young liver preparations permits meaningful conclusions, but it appears problematic for old preparations. Here it might be more practical to analyze the mixed distributions resulting from a determination of the DNA quantity or nuclear size alone.