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Modularity is defined as separation of a system into independent parts or modules that can be treated as logical and may be separated and recombined. Historically, the modularity represents the evolution of the concept of "low friction arthroplasty" developed by Sir J. Charnely in 1960. The disadvantage of a one-piece stem is the difficulty of restoring the biomechanical feature of the hip. Thus, the natural evolution was the introduction of modularity on both sides, the acetabulum and the femur. Modularity allows the surgeon to accurately match the anatomic characteristics of each patient to obtain improved range of motion, joint stability, abductor strength, and leg length equality. Disadvantages are related to the introduction of different interfaces, which could be sites of wear and corrosion. In accordance with the most recent literature, in primary total hip arthroplasty (THA) the modularity can be reduced to the head and the acetabular component, while a one-piece stem can manage the majority of cases. On the other hand, we believe that during revision surgery, a complete modularity is necessary.

The number of elderly people is steadily increasing: in the United States it will increase from 12.9% to 20% in 2030 with respect to the total population. Italy, with UK, Denmark and Sweden are the countries with the largest number of octogenarians (about 4% of the population) and it is estimated that this rate will increase by 300% over the next 50 years. The number of people affected by osteoarthritis will increase significantly and therefore the number of total hip arthroplasties will progressively increase. The success of an implant depends firstly by a flawless surgical technique, a correct and stable implant fixation and an optimal preoperative planning that should consider the bone quality of the patient, in order to choose a proper implant design. Different approaches could be followed to achieve adequate fixation: northern Europe surgeons prefer the cemented implant, instead American orthopedics generally use systems that allow a direct biological osteointegration. Elderly patients often present with multiple local and general problems that could affect significantly the normal course of a prosthetic surgery procedure and its results: they have bone tissue changes that lead to increased bone fragility and, consequently, difficulties to obtain primary stability. Osteoporotic bone is characterized by reduction of bone mass, decrease of cancellous bone trabeculae and by increased porosity of cortical bone. The bone fragility implies a greater risk of iatrogenic intraoperative fractures. Furthermore, difficulties linked to bone stock deficiencies become even more significant in revision surgery, where cortical bone thinning is associated with enlargement of the isthmus thus making more difficult to obtain distal fixation of prosthetic stems. At the moment, the role played by the drugs used for the treatment of osteoporosis during implant osteointegration is still not clearly understood and is still under investigation.

Distal radius fractures are the most frequent lesions encountered during clinical practice. The treatment is controversial and still debated in the literature. For a correct management of these lesions many authors recently emphasised the importance of anatomical reduction, a stable fixation and early joint mobilisation. We report our experience in the daily management of these lesions. The fractures are evaluated considering fracture type, fracture reduction criteria, adequacy of reduction criteria and overall fracture stability. The best treatment option must be decided in accordance to the type of fracture, the extent of metaphyseal comminution, the quality of the bone and the medical condition of the patient., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Reconstruction of the failed acetabular component in total hip arthroplasty (THA) can be challenging. Although there are multiple reconstructive options available, a cementless acetabular component inserted with screws has been shown to have good intermediate-term results and is the reconstructive method of choice for the majority of acetabular revisions This reconstruction is feasible provided at least 50% of the implant contacts host bone. When such contact is not possible, and there is adequate medial and peripheral bone, techniques using alternative uncemented implants can be used for acetabular reconstruction. An uncemented cup can be placed at a "high hip center." Alternatively, the acetabular cavity can be progressively reamed to accommodate extra-large cups. Oblong cups, which take advantage of the oval-shaped cavity resulting from many failed acetabular components, can also be used. The success of these cementless techniques depends on the degree and location of bone loss. The correct indication to revision and the choice of the correct implant is the keystone for the success of this type of surgery and follows an accurate preoperative planning in order to understand the specific pathologic scenario. The aim of this paper is to review some technical options for the revision of the acetabular component also taking into account our personal experiences and series.

In the case of extensively damaged meta-diaphyseal femoral bone with cortices thinning and widened femoral canal, tapered stems allow a good primary fixation and early weight-bearing. A retrospective review was conducted to evaluate long-term results of modular revision taper stems implanted from March 1999 to December 2002. Sixty-five consecutive hip revision surgeries were performed, mostly for aseptic loosening (75% of the cases). Femoral bone stock defects were classified according to AAOS's criteria and consisted mainly in type II (cavitary defects, 44.6%) and type III (combined defects, 33.9%). A trochanteric osteotomy was performed in 25 cases (38%) to remove primary implants that were cemented in 35 cases (54%). The mean postoperative follow-up was 109 months (range, 76 to 131 months). Clinical assessment at follow-up showed a significantly improved mean Harris Hip Score from 42 points preoperatively to 81 points postoperatively, while the x-ray examination did show a satisfactory distal integration of the stem in all cases and satisfactory reconstitution of the femoral bone stock in 47% of cases. The average subsidence of the stem at follow-up was less than one millimeter. According to data analysis, a leg-length discrepancy exceeding 15 millimeters caused significantly worse functional outcome and pain.

Fracture non-unions often complicate orthopaedic trauma. BMPs (bone morphogenetic proteins) are currently considered the most appealing osteoinductive agents. Applications of BMP-7 since January 2004 were prospectively recorded in a multicentre registry of aseptic femoral non-unions. The study included 30 patients who had undergone a median of 1 revision operation before BMP-7 application and who were followed up for a median 24 months. In 23/30 cases the application of BMP-7 was combined with revision of the fixation, and in 12 it was combined also with autograft. Non-union healing was verified in 26/30 cases in a median period of 6 months. No adverse events were associated with BMP-7 application. Our case series supports the safety and efficacy of BMP-7 in femoral non-unions. Multicentre networks and systematic, long-term follow-up of patients may improve understanding of this promising osteoinductive bone substitute., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Iliopsoas haematoma is an uncommon complication that may arise during anticoagulant therapy, especially with heparin and warfarin. Besides determining patient distress secondary to femoral nerve compression, this event may progress to life-threatening complications and require expensive treatments. We describe the case of a 70-year-old healthy man complaining of severe bilateral groin, lumbar and thigh pain, and paralytic ileus after therapy with heparin. The angio-computed tomography scan observed bilateral iliopsoas haematomas. In view of the clinical and radiological scenarios, we ordered a diagnostic and therapeutic angiography of the bleeding vessels by trans-catheter arterial embolization of the fourth right lumbar artery trunk. The treatment proved to be beneficial from a clinical, radiological and laboratory point of view. To the best of our knowledge, this is the first reported case of bilateral iliopsoas haematoma occurring in a male treated with therapeutic levels of heparin alone.

Summary: The effective treatment of the often debilitating, longlasting and large-asset-consuming complication of fracture non-unions has been in the centre of scientific interest the last decades. The use of alternative bone substitutes to the gold standard of autologous graft includes the osteoinductive molecules named bone morphogenetic proteins (BMPs). A multicenter registry and database (bmpusergroup.co.uk) focused on the application of BMP-7/OP-1 was created in December 2005. We present the preliminary results, using the prospective case-series of aseptic tibial non-unions as an example. Sixty-eight patients fulfilled the inclusion criteria for this observational study, with a minimum follow-up of 12 months. The median duration of tibial non-union prior to BMP-7 application was 23 months (range 9-317 mo). Patients had undergone a median of 2 (range 0-11) revision procedures prior to the administration of BMP-7. In 41% the application of BMP-7 was combined with revision of the fixation at the non-union site. Non-union healing was verified in 61 (89.7%) in a median period of 6.5 months (range 3-15 mo). No adverse events or complications were associated with BMP-7 application. The safety and efficacy of BMP-7 was verified in our case series, and was comparable to the existing evidence. The establishment of multicenter networks and the systematic and long-term follow- up of these patients are expected to provide further information and significantly improve our understanding of this promising osteoinductive bone substitute.

Introduction: Many kind of hydroxyapatite-coated cups were used, with favorable results in short term studies; it was supposed that its use could improve osteointegration of the cup, enhancing thus stability and survivorship. The purpose of this study is to analyze the long term behavior of the hemispheric HA coated, Dual Radius Osteonics cup and to discuss the way of failure through the exam of the revised components and of both periacetabular and osteolysis tissue., Materials and Methods: Between 1994 and 1997, at the Department of Orthopedic Sciences of the Insubria University, using the posterolateral approach, were implanted 276 Dual Radius Osteonics in 256 patients, with mean age of 63 years., Results: At a mean follow-up of 10 years (range 8-12 years), 183 cups in 165 patients, were available for clinical and radiographical evaluation. 22 Cups among the 183 were revised (11%). The cause of revision was aseptic loosening in 17 cases, septic loosening in one case, periprosthetic fracture in another case, osteolysis and polyethylene wear in two cases and, finally, recurrent dislocations in the last one. In the remaining patients, mean HHS increased from a preoperative value of 50.15 to a postoperative value of 92.69. The mean polyethylene wear was 1.25 mm (min. 0.08, max 3.9 mm), with a mean annual wear of 0.17 mm. The mean acetabular migration on the two axis was 1.6 mm and 1.8 mm. Peri-acetabular osteolysis were recorded in 89% of the implants (163 cases). The cumulative survivorship (revision as endpoint) at the time was 88,9%., Conclusion: Our study confirms the bad behavior of this type of cup probably related to the design, to the method of HA fixation. The observations carried out on the revised cup confirm these hypotheses but did not clarify if the third body wear could be a further problem. Another interesting aspect is the high incidence of osteolysis, which are often asymptomatic becoming a problem for the surgeon as the patient refuses the possibility of a revision.

Background: Dislocation is one of the most common complications of total hip arthroplasty with a reported dislocation rate of 3.2%. Despite increased experience with hip replacement, the overall rate has not yet changed. The aim of this paper is to review the most recent literature published on this topic and indexed in Medline, in order to clarify the main risk factors, and to standardize a treatment protocol of such an important complication of prosthetic surgery., Materials and Methods: Medline database was searched using key words: "hip dislocation", "hip instability" from 1980-2007. Studies were eligible for review and included if they met the following criteria: (1) publication in English, (2) clinical trials (3) review papers., Results: The risk of first-time dislocation as a function of time after the surgery is not well understood. Most, but not all, series have demonstrated that the risk of dislocation is highest during the first few months after hip arthroplasty; however, first-time late dislocation can also occur many years after the procedure. Several risk factors were described, including the surgical approach, the diameter of the head, impingement, component malposition, insufficient abductor musculature. In addition, there are also many treatment options, such as long-term bracing after closed reduction, component reorientation, capsulorraphy, trochanteric advancement, increasing offset, exchange of the modular head and the polyethylene liner, insertion of constrained liner., Conclusion: Preventing hip dislocation is obviously the best strategy. Surgeons must take into account patient and surgical risk factors. For patients at high risk for dislocation the surgeon should accurately restore leg length and femoral offset; the use of larger femoral heads, posterior transosseous repair of the capsulotendinous envelope if posterior approach is chosen or the use of a lateral approach should be considered. Proper patient education and postoperative care are very important.

Background: Trabecular Metal (TM) is a new highly porous material made of tantalum (Zimmer, Warsaw, Indiana, USA). Its three-dimensional structure is composed of a series of interconnected dodecahedron pores that are on average 550 microm in diameter. This size is considered optimal for bone ingrowth and is similar to trabecular bone. The elastic modulus of TM (3 GPa) is more similar to that of cancellous (0,1-1,5 GPa) or cortical (112-18 GPa) bone and is significantly less similar to that of Titanium (110 GPa) and Co-Cr alloys (220 GPa). These features enable bone apposition and remodeling. The purpose of the present study was to evaluate the histology of the bone-implant interface in a human specimen., Materials and Methods: A highly porous tantalum cup (Zimmer, Warsaw, Indiana, USA) was removed for recurrent dislocations three years after implantation. In order to obtain a slice of the cup, two cuts were made on the centre using an Exakt cutting machine. Then the slice was embedded in a Technovit resin and a Hematoxylin-eosin stain was used to study the bone tissue. Bone ingrowth was calculated using a method based on simple calculations of planar geometry., Results: The histological evaluation of the periprosthetic tissues revealed a typical chronic inflammation with few particles of polyethylene that were birefringent using polarized light. The quantitative evaluation of bone ingrowth revealed that more than 95% of voids were filled with bone., Discussion: In the literature, a lot of studies focused on tantalum were carried on animal model. Up to now little information is available about the histology of the bone-tantalum interface in a human artificial joint. We had an opportunity to remove a well integrated cup hence this study. The histology confirmed the strong relationship between the structure of this material and bone. The morphometric analysis revealed a high percentage of bone ingrowth.

Autogenous bone-grafting is frequently used in the treatment of fracture non-union. The donor-site morbidity and potentially limited supply of suitable autogenous bone are commonly recognized drawbacks. Recent studies advocated the benefit and safety of recombinant human bone morphogenetic protein-7 (rhBMP-7) in several anatomical sites. An observational, retrospective, non-randomized study on the use of BMP-7 in treating non-union in various sites has been carried out by the BMP-7 Italian Observational Study (BIOS) Group. The clinical series included 105 patients. Additional grafts were used based on the surgeon's decision. Radiographic and clinical assessments were carried out at progressive time intervals on two groups: BMP-7+autograft (A) or BMP-7 (B). The mean follow-up was 29.2 months. The last assessment showed an 88.8% success rate with an average healing time of 7.9 months. At >/=9 months there was overlapping between the unions recorded in the two groups (PA-PB=1.5%; CI 95%: -0.149; 0.119). This is an observational study that illustrates the efficacy of BMP-7 with and without bone grafting for the treatment of long bone non-unions.

An original modification in the Burton-Pellegrini technique was used to treat 20 cases of trapeziometacarpal arthritis between 1992 and 2001. A retrospective evaluation concerned 13 cases and was based on functional and radiographic criteria measuring the height of the column of the thumb at rest and under stress. Mean follow-up was 54.2 months (range 24-144). The height of the column of the thumb was decreased in relation to that of healthy hands and shortening under stress was significantly correlated with an increase in pain under stress (R2 = 44.7; p = 0.012). The observation of hyperextension of the MP (> 20 degrees) at follow-up was correlated with worse functional results. The method proposed has proven to be reliable, safe, capable of guaranteeing greater force as compared to other surgical methods described in the literature. The study emphasizes the need for a careful preoperative evaluation and possible treatment of MP joint hyperextension.

BACKGROUND: Local myogenesis, neoangiogenesis and homing of progenitor cells from the bone marrow appear to contribute to repair of the infarcted myocardium. Implantation into heart tissues of autologous skeletal myoblasts has been associated with improved contractile function in animal models and in humans with acute myocardial ischemia. Since heart infarction is most prevalent in individuals of over 40 years of age, we tested whether culture methods available in our laboratory were adequate to obtain sufficient numbers of differentiated skeletal myoblasts from muscle biopsy specimens obtained from patients aged 41 to 91. METHODS AND RESULTS: No matter of donor age, differentiated skeletal muscle cells could be produced in vitro in amounts adequate for cellular therapy (>/=300 millions). Using desmin as a cytoplasmic marker, about 50% cultured cells were differentiated along myogenic lineages and expressed proteins proper of skeletal muscle (myosin type I and II, actin, actinin, spectrin and dystrophin). Cytogenetic alterations were not detected in cultured muscle cells that had undergone at least 10 population doublings. Molecular methods employed for the screening of persistent viral infections evidenced that HCV failed to replicate in muscle cells cultured from one patient with chronic HCV infection. CONCLUSION: The proposed culture methods appear to hold promise for aged patients not only in the field of cardiovascular medicine, but also in the urologic and orthopedic fields.

A retrospective study was conducted to correlate the clinical result of joint replacement in dysplastic hips with the obtained modifications of the rotation centre. Sixty primary total hip arthroplasties were performed on 46 patients suffering from hip dysplasia at our institution. The radiographic evaluation of the hip rotation centre was performed using the method proposed by Pierchon. The clinical assessment was by Harris Hip Score. Our results revealed that it was possible to modify the position of the pathological rotational centre with a statistically significant difference (p<0.05) for both coordinates. The general clinical evaluation relates well to the radiological evaluation as the average HHS increased to 92.683 (p<0.05). The data from our study are in accordance with the most recent literature and confirm the importance of a suitable biomechanical position of the hip rotation centre in a distal and medial sense. (Hip International 2005; 15: 92-7).

The purpose of hip revision surgery is to relieve pain and restore hip function, while improving hip biomechanics and bone stock. The entity of bone stock impairment due to lysis indicates to the surgeon which revision stem he would preferably choose. Modern literature has described several options for stem revision, ranging from primary cemented/less implants in the case of limited proximal bone defects, to special revision stems where a massive femoral bone stock impairment is present. There are many classifications of the femoral bone-stock loss in the literature but most authors seem to agree that the treatment of minimal proximal defects should be performed with primary implant stems. The need to bridge a bigger bony gap makes distal fixation a good deal. Two options are described for this purpose: the Wagner stem and modular stems. Wagner's concept consists of a distal fixation based on the interference of the straight tapered titanium alloy stem at the level of the femoral isthmus, while longitudinal fins provide rotational stability. A wide variety of modular stems was lately developed to prevent major complication associated to the Wagner's stem, but some new problems arose from proximal overfill of the canal, difficult in assembly and fretting corrosion. Early experience with the new ZMR taper (Zimmer, Warsaw, IN, USA) modular revision stem is reported.

The authors report the results of the surgical treatment of supracondylar fractures of the humerus during childhood by closed reduction and percutaneous synthesis using Kirschner wires. A total of 16 patients were considered, who were re-examined at a mean follow-up of 57.9 months (24-84). The fractures were evaluated according to the Gartland classification modified by Wilkins. The results were classified based on Flynn criteria, and the duration of hospitalization and early and late complications such as neurovascular deficit and residual deformities were also taken into consideration. Final results were satisfactory in 94% of cases with no septic, vascular, or nervous complications. We observed remodeling of three fractures with defect in reduction of the distal fragment on a sagittal plane, and the absence of correction in a case of deficit in reduction on the frontal plane. Deformity persisted with no secondary displacement in 5 cases with correct postoperative reduction.

It is the purpose of this retrospective study to analyze factors capable of influencing clinical-functional and radiographic results, such as type of fracture, age of the patients, type of trauma, delay in treatment, associated lesions. A total of 33 fractures treated by open reduction and internal stabilization for fractures of the proximal tibia classified according to the AO were re-evaluated. Clinical and radiographic evaluation were obtained by assessing arthrosis, axis, and sinking of the tibial plateau. The clinical and functional results were satisfactory in 72.2% of cases, and radiographic ones were satisfactory in 63.6% for gonarthrosis, in 81.6% for axis, and in 84.8% for sinking. In conclusion, factors capable of influencing the results, such as type of fracture, age of the patient, and type of trauma, in addition to variables that the surgeon must monitor, such as reconstruction of the joint, alignment, synthesis, treatment of meniscal lesions, were observed.

An epidemiological survey of the use of antimicrobial prophylaxis in Italian hospitals was carried out under the auspices of the Journal of Chemotherapy. Out of 500 Italian orthopedic centers requested, 225 have participated in this study. A total of 136,321 surgical procedures were reported in the 166 centers reporting complete answers on type of surgery. They comprised hip and knee prosthesis (13.9%), spine surgery (4%), hip endoprosthesis (5.2%), osteosynthesis (26.9%), arthroscopy (24.4%), and others (25.5%). Perioperative antimicrobial prophylaxis was used in 75% of operations (ranging from 57.1% to 99.4% in arthroscopy and joint prosthesis, respectively). Short term (< 24 h) antimicrobial prophylaxis was performed in 38.4% of the 206 Centers answering this question correctly. 61.1% of Centers employed single agent prophylaxis. 70.8% of these prescriptions were betalactam antibiotics. Bacteriological analysis of the wound in 86 Centers (total number of isolates 2013) revealed the presence of Gram-positive isolates in 73.7% of cases. Methicillin resistance was expressed in 45% of 915 tested strains. Out of 4221 patients with high risk of infectious complications (joint prosthesis surgery) given antimicrobial prophylaxis in 46 Centers, the percentage of surgical wound infections was overall 2.1%, while that of non-surgical wound infections was 3.6%. A decrease in the total infection rate by about half was associated with long-term (> 24 h) as compared to short-term (< 24 h) antibiotic treatment (3.7 vs 7.6%, respectively), and with the use of antibiotic drug combinations vs single antibiotic drugs (3.9 vs 6.6%, respectively). The incidence of surgical-site infection is not decreased by extending the chemoprophylaxis for more than the first 24 h after surgery, while it is reduced from 2.5 to 1.4% by use of combination antibiotic therapy.

Purpose: Our purpose is a retrospective study of the results of diaphyseal humeral fracture treatment by elastic intramedullary nailing in comparison with plate osteosynthesis., Methods: Thirty cases were reviewed, with an average follow-up of 2 years. In 14 cases, flexible nails were used, and in the remaining 16 cases, A-O plates were used. We considered patients' sex and age, fracture type according to the A-O classification, type of treatment, consolidation defects, additional therapeutic procedures, healing time, and functional recovery. The surgical technique of elastic nailing appeared very simple, safe, and rather atraumatic because the nail is introduced in a retrograde manner and does not need proximal interlocking., Results: The results of elastic nailing, in terms of fracture healing time and functional recovery, appeared comparable with the results of plating, and complications appeared milder., Conclusion: We conclude that intramedullary elastic nailing is valid for routine use in appropriately selected humeral shaft fractures.

The surgical treatment of trauma in the C3-C7 region must obtain three goals: preservation of life, preservation or restitution of good neurological function, and achievement of stabilization that allows for early rehabilitation. In our experience we have come to believe that the goals set out to be achieved may be obtained if a correct anatomical-pathological classification of the lesion and the mechanism that caused trauma are kept clear: these premises are necessary for the choice of treatment and, consequently, the most suitable route of access.

The complications of prosthetic surgery in the dysplastic hip have specific features that are related to the conditions that make the realization of an implant technically complex; the altered primary acetabular and femoral morphology, the sequelae of previous non-substitutive surgery, and the consequent possible upsetting of joint biomechanics. It is possible to distinguish between complications relative to the skeleton, joint biomechanics, and soft tissues. Prosthetization of the acetabular skeletal aspect may encounter frequent errors in reconstruction (incongruous reaming-too much or too little-the improper use of bone grafts), errors in orientation of the acetabular component (excessive verticalization and anteversion) that are considered early complications. The same technical errors may cause late complications in the implant, or its migration. At the femoral level the particular shape of the medullary canal and of the femoral neck may lead to defects in orientation in anteversion and fracture of the diaphysis. Possible complications of a biomechanical nature are essentially to be related to changes in the center of rotation in both a craniocaudal and a mediolateral sense and or to the heterometry of the limbs. In the soft tissues, muscle tension may become too much or too little, in relation to recovery of joint biomechanics; in cases with significant lengthening neurologic deficit may occur. Accurate preoperative planning (traditional x-rays and CT scan), the choice of the most suitable surgical route of access, and the different prosthetic models that adapt best to the different morphological situations, the expertise of the surgeon, are all essential elements in monitoring complications.

Direct bone-metal contact is considered the ideal condition in order to obtain stability of orthopaedic non cemented implants. To acheive this result various implant shapes and surfaces were proposed.

The diagnostic accuracy of a workstation for neoplastic bone marrow pathology was evaluated on 526 cases from two institutions. The workstation consists of knowledge-based systems for peripheral blood analysis, flow cytometry immunophenotyping, and bone marrow morphology, linked together by a relational database. The "gold standard" diagnosis was established by complete agreement among three hematopathologists after independent review of the data from each case. The workstation's diagnosis agreed with the "gold standard" in 515 cases (97.9%). In six of the 11 diagnostic errors, the bone marrow module could not reach a final diagnosis. The five misclassifications would not have resulted in a change of therapy for the patient. The institutional diagnosis of record agreed with the gold standard in 462 cases (87.8%). The results indicate that the workstation is capable of high-quality, reproducible, multiparameter interpretive reporting.

In vertebral surgery we frequently observe patients who complain of lumbar pain at intervals of time which vary after surgery. The causes that may involve the persistence or the recurrence of these symptoms are many, after both decompression surgery, and spinal fusion. In order to favor a more rapid and accurate diagnosis, in our clinical we use a diagnostic algorithm based on the time at which the symptoms occurred. The most modern radiodiagnostic methods allow for a more accurate preoperative diagnosis and a more accurate diagnosis of the pathologies capable of perpetuating or re-accentuating lumbar pain postsurgery.

The degenerative processes of the lumbar spine generally initiate from the intervertebral disc, at the level of which progressive biochemical and structural changes take place leading to a modification in its physical properties of elasticity and mechanical resistance. Disc lesions cause pathological changes in the vertebral bodies, where osteophytes appear, and in the posterior joints. In more severe forms of the process the severe deformation of joint shape may lead to a condition of spondylolisthesis.

Quantitative assessment of bone resorption inhibition in vivo is not easily accomplished; methods relying on a count of osteoclasts are questionable, and histomorphometric evaluation of the bone mass presents several technical problems as well. The authors developed a simple method to measure the inhibition of bone resorption by study of the proximal tibial metaphysis of growing rats: the height of the perichondrial bone ring was taken as an index of the balance between osteoblastic and osteoclastic activity because any agent that inhibits osteoclasts (without interference with osteoblasts) produces an increase in the height of this anatomical structure. Since the ring is well demarcated by surrounding tissues, its height can be measured with accuracy and used for quantitative assessment of bone resorption inhibition. This model was tested with salmon calcitonin, and it provides evidence in vivo that this hormone inhibits osteoclastic bone resorption.

The localization of an osteochondroma in the spine is considered a rare occurrence. The authors describe the case of a 37 year-old woman with osteochondroma of the C2 neural arch involving the C1 spinous process. The woman came under observation because of severe loss of neck mobility and was subsequently diagnosed with osteochondroma. Of the preoperative examinations, MRI was more valuable than CT scan for defining the nature and extent of the tumor. Treatment consisted of complete posterior excision of the tumor, including the C1 spinous process and the C2 laminae up to the facets.

On the premise that cervical intersomatic spinal fusion in the treatment of traumatic or spondylolytic myelopathy and post-traumatic instability provokes degenerative arthritis due to functional overloading of the spaces adjacent to the fusion, 37 patients (average age 57, range 25-80) who had undergone spinal fusion by Cloward's technique were subjected to radiographic study and clinical evaluation. The average follow-up was 11.5 years (range 7-16 years). In comparison with a control group of the same age who had not undergone this operation, these patients' C3-C4 and C6-C7 spaces (adjacent to the most commonly fused vertebrae) were smaller by 16.7% and 15.9%, respectively. In spite of the worsening of the radiographic situation, from a clinical standpoint there was a significant improvement in the symptomatology of 86.5% of the patients. Thus the degenerative arthritis is both less evident and, as far as the long-term clinical outcome is concerned, less influential than could be expected. This finding is confirmed by the lack of statistical correlation between the clinical results and the radiographic evidence.

Muscle lesions induced by ischaemia have been investigated in depth from the morphological standpoint, though the metabolic changes thus caused are still the subjects of discussion. Measurements were therefore made of enzyme activities in rat calf muscle, and their changes following incomplete ischaemia. Three enzymes were studied: CPK (typical of muscle metabolism), G-6-PDH (pentose cycle, indicator of the extent of repair processes), and uptake of a labelled amino acid (L-leucine, on the part of tissue proteins. An initial increase in activity and uptake was followed by recovery functions, due to installation of a collateral circulation. This appeared to be complete by the 5th day.

In the attempt to identify enzymatic variations in the sural muscle of rats as a result of arterial ischaemia, the enzymatic variations of LDH, PHI, MDH, GOT, G-6-PDH and CPK were measured in a sural muscle in which both arterial ischaemia and venous stasis were induced. From the results examined it may be concluded that both techniques produce reversible lesions and that there is no significant difference in enzymatic activity between the two experimental conditions.

The authors describe a surgical procedure called multiple subtotal somatectomy. This operation is indicated when canal stenosis is caused by posterior protrusions of the anterior wall of the spinal canal (due to osteophytes, posttraumatic deformities, or tumoral lesions) involving three or more cervical segments. The procedure's principal phases are (1) removal up to the posterior longitudinal ligament of the central portion of three or more vertebral bodies, and (2) insertion into the prepared trench (15-mm wide) of an autologous graft, previously obtained from the iliac wing. Thirty-nine cases are presented (29 spondylosic myelopathies, 10 posttraumatic myelopathies), with follow-up periods varying from 6 months to 13 years. All grafts united, and 36 patients were benefited, while only three failed to improve.

The authors underline the importance of the precocious surgical treatment of the complex lesions of the carpal bones, especially in case of concomitant neurological lesions. The quality of the late results depends on the careful anatomical reconstruction and on the fixation during a suitable period with the aim to obtain a satisfactory repair of the carpal ligaments.

The principles underlying the use of isoelastic shoulder prostheses are discussed and the results obtained in 8 patients are reported. Two operations were for pseudarthrosis of the humeral neck and 6 for osteolytic neoplasms. The results were assessed after an average follow-up of 4 years. Full movement was never recovered; there was partial recovery in 6 cases, and no significant recovery in 2. The extent of the surgical resection was determined by the type of lesion; in more conservative resections which allowed for the reconstruction of tendinous insertions, the functional results were better than in wide resections. The difficulty of recovering good movement was related to the limited possibilities of reconstructing the insertions of the external rotator muscles.

Bioactive glass fibers have been prepared and implanted in cortical defect and in muscle. The fibers can act as a substrate for bone apposition, when implanted in a cortical defect, and become incorporated in the new bone matrix. The same results were obtained when fibers were implanted in a muscle pouch together with bone marrow cells. An intense inflammatory reaction was observed when bioactive glass fibers were implanted in muscle; the reaction was milder when fibers were implanted in bone or in muscle together with bone marrow cells. This fact supports the hypothesis that osteogenic cells adhere in an early phase to the substrate and prevent recognition of the foreign material by inflammatory cells. This appears to be a fundamental condition for direct bone matrix apposition on the surface of fibers.

The authors discuss the clinical and therapeutic problems of post irradiation lesions of the brachial plexus resulting from radiotherapy in the treatment of breast cancer. Twelve such cases were referred to our clinic in the 2 year period ending June 1980. The results after 2 years are reported and the literature on the subject is reviewed. Surgical treatment aimed at mobilising the nerve roots (neurolysis) is recommended, but we would stress that the best treatment is prophylactic. With more strict control of the radiotherapeutic technique, particularly with regard to the total dosage administered, it should never happen.