Is there any difference between tapered titanium stems with similar geometry and hydroxyapatite coating?

PURPOSE: Several tapered stems with similar geometry and extensive hydroxyapatite coating have recently been introduced. It is not clear, however, whether they share the same design or whether they exhibit any difference that might affect their clinical performances. In this study, we analysed five tapered stems fully coated with hydroxyapatite to establish whether they exhibit similar geometric features and may therefore be used indifferently when a cementless stem is indicated. METHODS: The length of the stem, the coronal and sagittal diameters, the length of the stem shoulder and the metadiaphyseal angle were measured. The ratio between the proximal and distal coronal diameters of the stem and that between the proximal and distal cross-sectional areas were calculated as a flare index and tapered index, respectively. RESULTS: The proximal coronal diameter ranged between 24.9 and 28 mm in the smaller size and between 34 and 38.4 mm in the largest sizes. The proximal sagittal diameter ranged between 10.2 and 11.8 in the smallest size and between 14.4 and 17.2 in the largest. A significant difference was found between stems of different brands in the flare index, tapered index, length of stem shoulder and metadiaphyseal angle. CONCLUSIONS: Lookalike tapered stems with extensive HA coating actually exhibit significant differences in several geometric features potentially affecting their clinical performances. As a result, these stems should not be used indifferently, but rather they should be selected on the basis of the femoral morphology of the operated patient.

Results of primary repair of distal triceps tendon ruptures in a general population: a multicentre study.

Aims: The aim of the study was to analyze the results of primary tendon reinsertion in acute and chronic distal triceps tendon ruptures (DTTRs) in the general population. Patients and Methods: A total of 28 patients were operated on for primary DTTR reinsertions, including 21 male patients and seven female patients with a mean age of 45 years (14 to 76). Of these patients, 23 sustained an acute DTTR and five had a chronic injury. One patient had a non-simultaneous bilateral DTTR. Seven patients had DTTR-associated ipsilateral fracture or dislocation. Comorbidities were present in four patients. Surgical treatment included transosseous and suture-anchors reinsertion in 22 and seven DTTRs, respectively. The clinical evaluation was performed using Mayo Elbow Performance Score (MEPS), the modified American Shoulder and Elbow Surgeons Score (m-ASES), the Quick Disabilities of the Arm, Shoulder and Hand score (QuickDASH), and the Medical Research Council (MRC) Scale. Results: A total of 27 patients (28 DTTRs) were available for review at a mean of 47.5 months (12 to 204). The mean MEPS, QuickDASH, and m-ASES scores were 94 (60 to 100), 10 (0 to 52), and 94 (58 to 100), respectively. Satisfactory results were observed in 26 cases (93%). Muscle strength was 5/5 and 4/5 in 18 and ten DTTRs, respectively. One patient with chronic renal failure experienced a traumatic rerupture of distal triceps. One patient (1 DTTR) experienced mild elbow stiffness. Conclusion: Primary repair of acute and chronic DTTRs in a general population yields satisfactory results in the majority of patients with a low rerupture rate. Cite this article: Bone Joint J 2018;100-B:610-16.

Mapping of the anterior tibial profile to identify accurate reference points for sagittal alignment of tibial component in total knee arthroplasty.

BACKGROUND: Although standard instrumentation is the procedure most frequently used to implant a Total Knee Arthroplasty (TKA), high rates of malalignment of tibial component are reported using this technique. Anatomical landmarks for sagittal alignment have been little investigated and the best reference axis, which parallels the mechanical axis, is yet to be established. HYPOTHESIS: Mapping the Anterior Tibial Profile (ATP) may allow the identification of segmental zones of the ATP parallel to the mechanical axis which can be used to align the extramedullary rod. METHODS: An intramedullary rod was positioned in line with the mechanical axis in 47 dried cadaveric tibiae. The rod was connected to a cutting jig and to an extramedullary rod. Digitalized images of lateral view radiographs were taken and the distance between the ATP and the extramedullary rod was measured at 10-mm intervals and at interpolated distances corresponding to every 2% of the tibial length. RESULTS: Segmental portions of the ATP exhibit an alignment parallel to the mechanical axis between points located at 58% and 90% and at 62% and 88% of the tibial length. Points placed at 50% of tibial length and 5mm proximal to the ankle joint generate the longer axis parallel to the mechanical axis. CONCLUSION: The orientation of sagittal tibial cut may be improved by aligning the extramedullary rod parallel to the ATP at definite points. Points placed at 50% of the tibial length and 5mm proximal to the ankle joint may be preferred since they generate the longer axis parallel to the mechanical axis and are more easily identified at surgery.

Preserving the PCL during the tibial cut in total knee arthroplasty.

PURPOSE: Previous studies have shown that the PCL insertion may be damaged during the tibial cut performed in total knee arthroplasty. We investigated the maximum thickness of a tibial cut that preserves the PCL insertion and to what extent the posterior slope of the tibial cut and that of the patient's tibial plateaus affect the outcome. METHODS: MR images of 83 knees were analysed. The maximum thickness of a tibial cut that preserves the PCL using a posterior slope of 0°, 3°, 5° and parallel to the patient's slope of the tibial plateau, was evaluated. Correlations between the results and the degrees of the posterior slope of the patient's tibial plateaus were also investigated. RESULTS: The maximum thickness of a tibial cut that preserves the entire PCL insertion was, on average, 5.5, 4.7, 4.2 and 3.1 mm when a posterior slope of 0°, 3°, 5° and parallel to the patients' tibial plateaus was used, respectively. When the 25th percentile was considered, the maximum thickness of a tibial cut that preserved the PCL was 4 and 3 mm with a tibial cut of 0° and 5° of posterior slope, respectively. The maximum thickness of a tibial cut that preserved the PCL was significantly greater in patients with a sagittal slope of the tibial plateaus more than 8° than in those with a sagittal slope less than 8°. CONCLUSION: In cruciate retaining implants, the PCL insertion may be spared in the majority of patients by performing a tibial cut of 4 mm, or even less when a posterior slope of 3°-5° is used. The clinical relevance of our study is that the execution of a conservative tibial cut, followed by a second tibial resection to achieve the thickness required for the tibial component to be implanted, may be an alternative technique to spare the PCL in CR TKA. LEVEL OF EVIDENCE: II.

Improving tibial component alignment in total knee arthroplasty.

PURPOSE: Tibia torsion may influence the accuracy of extramedullary instrumentations in total knee arthroplasty (TKA). This study assessed whether the effect of tibial torsion may be overcome using a surgical technique in which the extramedullary rod is aligned to reference points at the proximal tibia only. METHODS: A consecutive series of 94 knees that underwent TKA were analyzed. In the first 47 knees (group 1), a standard procedure for tibial component alignment was performed while in the second group of 47 knees, a modified surgical technique was used including the alignment of the extramedullary rod to the reference points at the proximal tibia only (group 2). Lower limb, femoral, and tibial component alignment were measured on postoperative long-leg radiographs. RESULTS: Femorotibial mechanical axes angles were similar in the two groups. Femoral component alignment also did not differ between the groups. A neutral alignment of the tibial component was achieved in 17 and 34 % of the knees in group 1 and group 2, respectively (p = 0.04). A malalignment of the tibial component >3° was found in 34 % of knees in group 1 compared with 4 % of those in group 2 (p = 0.0001). CONCLUSIONS: Coronal alignment of the tibial component may improve by setting the extramedullary rod in line with anatomical references in the proximal tibia only. This technique appears to bypass the influence of tibial torsion on the alignment of the extramedullary guide at the distal tibia. The clinical relevance of the study is that using this technique, the rate of malalignment of the tibial component may be reduced compared to a standard technique in which a fixed reference is used at the ankle joint.

Thigh pain, subsidence and survival using a short cementless femoral stem with pure metaphyseal fixation at minimum 9-year follow-up.

BACKGROUND: Short femoral stems designed to spare bone stock and improve load transfer at the proximal femur level have been introduced in recent years. However, little is known on the long-term outcomes of these stems. HYPOTHESIS: Short cementless stems have low rate of thigh pain and subsidence as well as few revision needs at mid-term follow-up. MATERIALS AND METHODS: We prospectively followed 64 patients (72 hips) undergoing total hip arthroplasty with a femoral stem designed to achieve a pure metaphyseal fixation. Patients with hip fracture, femoral neck deformity and osteoporotic bone were excluded. Clinical evaluations were performed annually until the last follow-up, a minimum of 9 years after surgery. At each follow-up, implant positioning was assessed on conventional plain films with a computer assisted radiographic evaluation. RESULTS: The Harris hip score improved from 43 points (range 19-50) before surgery to 88 points (range 73-100) at the final follow-up (P=0.001), and the Womac score averaged 47 points (range 35-56 points) preoperatively and 76 points (range 63-84) at the last follow-up (P=0.001). Thigh pain was reported by five patients (8%) at the 2-year follow-up, but only in two (3%) was still present, and related to the prosthesis, at last follow-up. Computer assisted radiographic analysis showed a neutral alignment of the stem in 56% of cases, a varus-valgus alignment less than 5° in 36% and equal to 5° in 8%. Stem subsidence was observed in 12 hips but was less than 4mm in all cases (range 0-3mm). Calcar height remained unchanged over time. Adaptive bone remodelling, including proximal bone resorption and distal cortical hypertrophy were not observed at follow-up. No patients had aseptic loosening of the stem nor were radiolucent lines detectable at the level of the porous coating. Survivorship analysis showed a 100% survival rate of the stem at nine years. DISCUSSION: This study showed that a femoral stem designed to achieve a pure metaphyseal fixation may obtain, in a selected group of patients with adequate bone quality, satisfactory clinical outcomes without compromising implant stability. The limited periprosthetic bone remodelling observed after a minimum of 9 years follow-up suggests that this type of implant may improve mechanical stresses on host bone compared with standard stems requiring diaphyseal fixation. LEVEL OF EVIDENCE: Level IV. Historical series.

Correlation between posterior offset of femoral condyles and sagittal slope of the tibial plateau.

The aim of this study was to address, in normal knees, the variability of posterior offset of femoral condyles and tibial slope, and the presence of any correlation between the two that might be needed to achieve an adequate joint motion in flexion. Magnetic resonance images of normal knees of 80 subjects, 45 males and 35 females, with a mean age of 38.9 years, were analysed. Measurements were performed by two independent observers using an imaging visualization software. The tibial slope averaged 8 and 7.7 °, on the medial and lateral sides, respectively (P = 0.2); the mean posterior offset of femoral condyles was 27.4 and 25.2 mm on the two sides, respectively (P = 0.0001). The variation coefficient of the condylar offset and tibial slope was 11.5 and 38%, respectively. In the medial compartment, a significant correlation was found between the femoral condylar offset and the tibial slope, while the same was not observed in the lateral compartment of the knee. Magnetic resonance imaging allows the assessment of tibial slope and femoral condylar offset in the medial and lateral side separately, taking into account any difference between the two compartments. The sagittal tibial slope exhibits a greater variability compared with the posterior offset of femoral condyles. The correlation found, in the medial compartment, between the tibial slope and femoral condylar offset suggests that the reconstitution of the proper morphology of the posterior part of the knee joint may be necessary to obtain a full range of motion in flexion after total knee replacement.

[The difficult start of nephrology in Rome]. / La difficile nascita della Nefrologia Romana.

Nephrology in Rome began in the 1960s with the arrival of Ernico Fiaschi in the wake of Cataldo Cassano at the Institute of Medical Pathology (later on Clinica Medica II). A group of doctors interested in nephrology was set up, with among them Giulio A. Cinotti, who was to become full professor of nephrology at the University of Rome ''La Sapienza'' in 1980. By the end of the 1960s, the renal transplant activity had become an important asset at the Institute of Surgical Pathology (later on Clinica Chirurgica II) thanks to Paride Stefanini. A chair of surgical nephrology was instituted at the Urology Clinics of Ulrico Bracci; the chair was first held by Nicola Cerulli, who developed an intensive hemodialysis program. Around the same time, the Center for the Research and Treatment of Arterial Hypertension and Kidney Diseases became operational at the hospitals of Rome (under the responsibility of Vito Cagli at the Policlinico Umberto I), while a nephrology and dialysis unit, directed by Giancarlo Ruggieri, was set up at the San Giacomo Hospital. Many nephrology-related ''cultural'' activities started to be undertaken thanks to the ''Gruppo Laziale di Nefrologia Medica e Chirurgica'' founded by Drs Cagli, Cerulli, and Cinotti. Two national congresses were organized by Giulio Cinotti in 1979 (Fiuggi) and 1992 (Rome).

Experimental posterolateral spinal fusion with porous ceramics and mesenchymal stem cells.

Alternatives to autogenous bone graft for spinal fusion have been investigated for many years. It has been shown that osteoconductive materials alone do not give a rate of fusion which is comparable to that of autogenous bone graft. We analysed the effectiveness of porous ceramic loaded with cultured mesenchymal stem cells as a new graft material for spinal fusion in an animal model. Posterolateral fusion was carried out at the L4/L5 level in 40 White New Zealand rabbits using one of the following graft materials: porous ceramic granules plus cultured mesenchymal stem cells (group I); ceramic granules plus fresh autogenous bone marrow (group II); ceramic granules alone (group II); and autogenous bone graft (group IV). The animals were killed eight weeks after surgery and the spines were evaluated radiographically, by a manual palpation test and by histological analysis. The rate of fusion was significantly higher in group I compared with group III and higher, but not significantly, in group I compared with groups II and IV. In group I histological analysis showed newly formed bone in contact with the implanted granules and highly cellular bone marrow between the newly formed trabecular bone. In group II, thin trabeculae of newly formed bone were present in the peripheral portion of the fusion mass. In group III, there was a reduced amount of newly formed bone and abundant fibrous tissue. In group IV, there were thin trabeculae of newly formed bone close to the decorticated transverse processes and dead trabecular bone in the central portion of the fusion mass. In vitro cultured mesenchymal stem cells may be loaded into porous ceramic to make a graft material for spinal fusion which appears to be more effective than porous ceramic alone. Further studies are needed to investigate the medium- to long-term results of this procedure, its feasibility in the clinical setting and the most appropriate carrier for mesenchymal stem cells.

Recovery of motor deficits after microdiscectomy for lumbar disc herniation.

We have studied, prospectively, 116 patients with motor deficits associated with herniation of a lumbar disc who underwent microdiscectomy. They were studied during the first six months and at a mean of 6.4 years after surgery. Before operation, muscle weakness was mild (grade 4) in 67% of patients, severe (grade 3) in 21% and very severe (grade 2 or 1) in 12%. The muscle which most frequently had severe or very severe weakness was extensor hallucis longus, followed in order by triceps surae, extensor digitorum communis, tibialis anterior, and others. At the latest follow-up examination, 76% of patients had complete recovery of strength. Persistent weakness was found in 16% of patients who had had a mild preoperative deficit and in 39% of those with severe or very severe weakness. Muscle strength was graded 4 in all patients with persistent weakness, except for four with a very severe preoperative deficit affecting the L5 or S1 nerve root. They showed no significant recovery. Excluding this last group, the degree of recovery of motor function was inversely related to the preoperative severity and duration of muscle weakness. The patients' subjective functional capacity was not directly related to the degree of recovery except in those with persistent severe or very severe deficit.

[Syndrome of inappropriate ADH secretion: a late complication of hemopoietic stem cell allograft]. / Sindrome da inappropriata secrezione di ormone antidiuretico: una complicanza tardiva del trapianto di cellule staminali emopoietiche.

An 11-year old boy with acute lymphoid leukemia underwent umbilical cord stem cell infusion. This was followed at day 15 by the onset of asymptomatic hypotonic isovolemic hyponatremia. The disorder could be attributed to a syndrome of inappropriate ADH secretion (SIADH), most probably related to the massive i.v. induction treatment with cyclophosphamide. The major causes and clinical variants of SIADH are reviewed, with particular emphasis on the complications of chemotherapy in hematological diseases. Worsening of hyponatremia during routine parenteral feeding, as opposed to normalization of plasma Na+ by infusion of hypertonic saline, emphasize the importance of early accurate diagnosis and careful follow-up of these iatrogenic sequelae of stem cell allograft.

IgA nephropathy: multivariate statistical analysis aimed at predicting outcome.

BACKGROUND: Several risk factors of IgA nephropathy (IgAN) have been identified, but their importance in predicting outcome is still controversial. METHODS: We conducted a retrospective study on 119 patients (pts) with IgAN. All had a follow-up of over five years (mean 134+/-56 months). For each patient we recorded age, 24h proteinuria, hematuria, renal function (RF), arterial hypertension (AH) and histological features. Multivariate analysis was done for predictive purposes (segmentation, using Chi-squared Automatic Interaction Detection-CHAID). RESULTS: AH at the time of renal biopsy was the principal and independent predicting factor: 30/50 (60%) hypertensive pts had serum creatinine > or =1.5 mg/dL at the end of follow-up compared to 9/69 (13%) pts with normal blood pressure. Age was a further predictive parameter: 21/28 (75%) pts with AH and age over 39 years had reduced RF at the last examination. In this subgroup, 18/19 (95%) with evidence of tubulo-interstitial lesions showed a decline of RF. CONCLUSIONS: AH and age alone are significant prognostic factors; tubulo-interstitial lesions are an additional pointer to poor outcome in these pts. The algorithm obtained with segmentation analysis may be a guideline for prognosis in single patients with IgA nephropathy.

Monocyte/mesangial cell interactions in high-glucose co-cultures.

BACKGROUND: Monocytes bind to human mesangial cells (HMC) in a co-culture model of leukocyte/ glomerular cell interactions. Since monocytic infiltration has been demonstrated in the early stages of diabetic glomerulopathy, we examined whether co-culture with myelomonocytes of the U937 cell line in media mimicking the diabetic microenvironment modulated phenotype, growth, and extracellular matrix production patterns of HMC. METHODS: HMC monolayers grown for 5 days in 5.5 mmol/l (NG) or 30 mmol/l (HG) glucose media were examined 3, 24 and 48 h after addition of U937 cells by computer-assisted image analysis/fluorescence microscopy following fixation, staining for cell adhesion, and TUNEL/propidium iodide labelling for apoptosis. As matrix components may be relevant to both phenotype of cultured HMC and monocyte adhesion, reverse transcription-polymerase chain reaction, zymography, and ELISA were used to detect urokinase-plasminogen activator (uPa), collagen type IV (COL IV), transforming growth factor beta1 (TGF-beta1), matrix metalloproteinases (MMP), and relative inhibitors (tissue inhibitor of MMP (TIMP)) expression in co-cultures in NG/HG. RESULTS: U937 adhesion at 1-3 h was increased in HG (from 54.9+/-6.6 to 87.1+/-5.8% U937/HMC). Control HMC proliferating in NG supplemented with 10% fetal bovine serum had an average cross-sectional area of 9993+/-505 micro(2) with 1.2+/-0.1 hillocks/high-power field, which increased to 13 651+/- 1114 micro(2) with 0.5+/-0.2 hillocks/high-power field in HG (P<0.05). TUNEL+HMC were nearly identical (4.9+/-1.7 vs 4.2+/-0.4% in HG, P=NS). Enhanced transcription and secretion of urokinase (uPA, +656%), COL IV (+137%), TGF-beta1 (+590%) were observed in co-cultures in HG. COL IV and TGF-beta1, but not uPA, were also increased in HMC alone, exposed to HG for 5 days. MMP-2/TIMP-2 ratio was decreased while MMP-1/TIMP-1 was increased in HG co-cultures. In both NG and HG, U937 adhesion reduced HMC number and hillocks at 24 h, with constant apoptosis. The effects of U937 were no longer detectable at 48 h, when apoptosis was 2.1+/-0.6 vs 4.0+/-0.4% in HG, and cell counts returned above basal, possibly due to a delayed proliferative response. CONCLUSIONS: High glucose medium increases U937 cell adhesion to HMC. In turn, monocytes modulate number and spatial distribution of HMC, which are also markedly affected by ambient glucose levels. These interactions may be relevant to leukocyte infiltration, mesangial expansion, and glomerulosclerosis in diabetes.

Effect of Lisinopril on the progression of renal insufficiency in mild proteinuric non-diabetic nephropathies.

BACKGROUND: The aim of the study was to determine whether Lisinopril, an ACE-inhibitor (ACEi), was more effective than other antihypertensive agents in slowing the progression of non-diabetic chronic renal diseases in patients with baseline proteinuria < or =1.0 g/day. METHODS: In an open, multicentre study all eligible patients entered a 3 months run-in phase during which antihypertensive therapy (with exclusion of ACEi) was adjusted in order to obtain a supine diastolic blood pressure < or =90 mmHg and urinary protein excretion and renal function stability were verified. One hundred and thirty-one patients with chronic renal insufficiency (Clcr between 20-50 ml/min) because of primary renoparenchymal diseases and proteinuria < or =1.0 g/day, were randomized to Lisinopril (L=66) or alternative antihypertensive therapy (C=65). Changes in renal function were assessed by inulin (Clin) clearance. RESULTS: During the follow-up period of 22.5+/-5.6 months, Clin did not change significantly in group L (-1.31+/-0.6 ml/min/1.73 m(2)) differing significantly from group C in which it declined markedly (-6.71+/-3.6 ml/min/1.73 m(2)) (P<0.04). Seven patients experienced adverse events that prompted discontinuation of treatment: four in group L and three in group C; in addition seven patients showed severe deterioration in renal function requiring dialysis: two in group L and five in group C. The overall risk of the combined end-points: need for dialysis or halving of GFR was significantly higher in group C versus group L. During the study the mean value for systolic blood pressure was 137.8+/-14.6 SD mmHg in group L and 140.8+/-14.1 SD mmHg in group C; the mean difference between groups, during and at the end of the study, was 2 mmHg (NS). The mean diastolic blood pressure during the study was 83.8+/-8.6 SD mmHg in group L and 84.3+/-7.56 SD mmHg in group C; during and at the end of the study the mean diastolic difference between groups was 1 mmHG: CONCLUSION: This study, employing a sensitive measurement of renal function and with similar blood pressure in both groups, provides support to the hypothesis that ACEi have a specific renoprotective effect, in addition to blood pressure control, also in patients with mild proteinuria.

Changes in bone turnover after parathyroidectomy in dialysis patients: role of calcitriol administration.

BACKGROUND: Available data on changes in serum levels of bone markers after parathyroidectomy (PTx) in dialysis patients are not uniform. Changes are thought to be due to either a reduction in PTH activity per se or to a direct effect of vitamin D therapy on bone cells. We aimed to verify whether treatment with vitamin D modifies serum levels of markers of bone synthesis (alkaline phosphatase (AP), osteocalcin (BGP), procollagen type I C-terminal peptide (PICP)) and resorption (collagen type I C-terminal peptide (ICTP)) within a period of 15 days in haemodialysis patients with severe secondary hyperparathyroidism following PTx. METHODS: We randomized two groups (A, treatment and B, placebo, 10 patients each) with comparable basal PTH values and measured bone markers 3, 7 and 15 days after surgery. All patients were treated with calcium supplements (i.v. and p.o.), and group A also received calcitriol (2.4+/-1.0 microg/day, p.o.). RESULTS: In both groups, PTx induced significant changes in all the markers evaluated, except for BGP in group B. Compared to basal values, ICTP decreased from 481+/-152 ng/ml in group A and 277+/-126 ng/ml in group B to 267+/-94 and 185+/-71 ng/ml (M+/-SD) respectively, and PICP increased from 307+/-139 ng/ml in group A and 309+/-200 ng/ml in group B to 1129+/-725 and 1231+/-1267 ng/ml (M+/-SD) respectively, within 3 days of surgery. AP values increased after 15 days from 1115+/-734 mU/ml in group A and 1419+/-1225 mU/ml in group B to 1917+/-1225 and 1867+/-1295 mU/ml (M+/-SD) respectively. On the contrary, mean values of BGP were never different from basal levels after PTx in either group. In the two groups, the pattern of changes of all the bone markers after PTx was almost identical. Group A patients predictably required lower doses of oral calcium supplements to correct hypocalcaemia (16. 9+/-5.7 vs 22.1+/-5.0 g/10 days; M+/-SD, P<0.04). CONCLUSIONS: The opposite behaviour of serum PICP and ICTP after PTx, in both the treated and untreated groups suggests that quantitative uncoupling between bone synthesis and resorption is responsible for hypocalcaemia. This phenomenon, as reflected by the evaluated bone markers, is unaffected by calcitriol. Based on our data we conclude that immediately after parathyroid surgery, vitamin D therapy does not influence bone cell activity, but improves hypocalcaemia mainly through its known effect on intestinal calcium absorption.

Efficiency of different hollow-fiber hemofilters in continuous arteriovenous hemodiafiltration.

Low dialysate to blood flow rate ratios are a unique characteristic of continuous arteriovenous hemodiafiltration (CAVHDF) that should allow complete saturation of dialysis fluid with small-molecular-weight blood solutes. The aim of the investigation was to evaluate the performance of different hemofilters in CAVHDF. In 10 critically ill patients with acute renal failure, the efficiency of four hollow-fiber hemofilters, polyamide 0.6 m(2), polyacrylonitrile (PAN) 0.3 and 0.6 m(2), acrylonitrile sodium methallylsulfonate (AN69HF) 0.6 m(2), has been evaluated. For comparison, dialysate flow rates (Q(di)) were standardized to 16.6 and 25 ml/min. Samples for urea nitrogen were obtained from the arterial blood line (C(bi)) and from the dialysate exit port (C(do)) within 24-hour running time. Outflowing dialysate (Q(do)) was also measured at the same time. Blood flow (Q(b)) was calculated by the bubble transit time technique. Diffusive and total urea clearances were determined. AN69HF and PAN hemofilters provided higher clearances than the polyamide hemofilter. Despite the smaller surface area, PAN 0.3 m(2) had a total urea clearance comparable to that of PAN 0.6 m(2) and AN69HF at Q(di) = 16.6 ml/min. While at Q(di) = 16.6 ml/min equilibrium between blood and dialysate (C(do)/C(bi) congruent with 1) occurred with the AN69HF and PAN hemofilters, at Q(di) = 25 ml/min the equilibrium was obtained only with the AN69HF hemofilter. In conclusion, almost complete urea saturation of dialysis fluid has not been obtained with all hemofilters tested here. In our experience, membrane characteristics play an important role in determining diffusive efficiency in CAVHDF.

Anterior shoulder dislocation in adolescents.

Of 780 patients treated for primary anterior shoulder dislocations, 33 (4.2%) were aged 12 to 17 years at the time of the dislocation. We clinically evaluated 28 of these patients a mean of 7.1 years after the initial dislocation. All patients were radiographed, and 15 underwent magnetic resonance imaging or computed arthrotomography of the shoulder. The primary dislocation had been traumatic in 21 patients (75%) and atraumatic in 7 patients (25%). Recurrent dislocations had occurred in 24 cases (86%), the number of recurrences ranging from 1 to 30. In the group with traumatic primary dislocations, the rate of recurrences was 92% and the mean number of redislocations was 7 in the patients who had been 14 to 17 years of age at the time of the initial injury, whereas the corresponding figures were 33% and 0.3 in the patients who had been 13 years of age or less at the time of the initial injury. Imaging studies showed a Bankart lesion in 80% of cases; each of these patients had had a traumatic primary dislocation and was 14 to 17 years old at the time of injury. During the follow-up period, operative stabilizing procedures had been performed in 7 cases. At follow-up evaluations, all nonoperated patients showed clinical evidence of anterior or multidirectional instability of the involved shoulder; of the operated patients, each of those with traumatic primary dislocations reported no recurrences and had a satisfactory result, whereas both of the patients with atraumatic primary dislocations continued to have subluxation and/or dislocations of the operated shoulder. In the 14- to 17-year-old adolescents with traumatic primary dislocations in whom imaging studies show Bankart lesions, there is an indication for prophylactic stabilizing surgery at the time of the initial injury.

The morphometry of the coracoid process - its aetiologic role in subcoracoid impingement syndrome.

Anatomical morphometric studies of the coracoid process and coraco-glenoid space were carried out on 204 dry scapulae. No statistically significant correlations were found between length, or thickness of the coracoid process, prominence of the coracoid tip, coracoid slope, coraco-glenoid distance, or position of the coracoid tip with respect to the uppermost point of the glenoid. These anatomical characteristics were independent of the dimensions of the scapulae. Three configurations of the coraco-glenoid space were identified. Type I configuration was found in 45% of scapulae and Type II and Type III, in 34% and 21% of specimens, respectively. The lowest value of the coraco-glenoid distance were seen in Type I scapulae. Morphometric characteristics which might predispose to subcoracoid impingement were found in 4% of Type I scapulae. A total of 27 scapulae, nine with each type of configuration were submitted to CT scanning. Scapulae with a Type I configuration were found to have low values for the coraco-glenoid angle and coracoid overlap, which are known to be associated with a short coraco-humeral distance. Subjects with a Type I configuration, and severe narrowing of the coraco-glenoid space, appear to be predisposed to coraco-humeral impingement. These morphometric characteristics may be easily evaluated on CT scans.