Osteopenic Bone Research Articles

Results and Complications of a Surgical Technique for Correction of Coxa Vara in Children With Osteopenic Bones

Surgical correction of coxa vara in children with osteopenic bone diseases could be very challenging. In this study, we describe a modified surgical technique for the correction of coxa vara in children with bone fragility. We also report the results and complications of this technique in 16 children (21 coxa vara) with osteopenic bone diseases. Charts, clinic notes, and radiology images of 16 patients (21 hips) who had a proximal femoral osteotomy for the treatment of coxa vara in osteogenesis imperfecta (18 hips) and fibrous dysplasia (3 hips) in our institution between 1996 and 2005 were reviewed. The modified surgery involved an intertrochanteric osteotomy and the use of Kirshner wires and intramedullary rods. Neck-shaft angle, Hilgenreiner-epiphyseal angle, and head-shaft angle were assessed at preoperative, postoperative, and final follow-up. The average age at surgery was 8.3 years (range, 3.3-15.8 years). The average correction of the neck-shaft angle was from 84.6 to 114.4 degrees, and for the Hilgenreiner-epiphyseal angle, it was from 67.7 to 42 degrees at final follow-up. All osteotomies were healed at 3 months postoperatively. The mean follow-up was 4.29 years (range, 1.70-8.12 years). The average improvement in abduction and external rotation of the hips was 14 and 15 degrees, respectively. There were no cases of infection and 2 cases (12%) of implant-related complications. One patient with fibrous dysplasia needed replacement of the intramedullary rod and additional distal femoral osteotomy 1 week postsurgery. In another patient, the intramedullary rod had migrated proximally, which was corrected 5 months postsurgery by advancing the rod distally. Results suggest that this surgical technique provides satisfactory correction of coxa vara in children with osteopenic bone diseases. The described surgical technique used to correct coxa vara is reproducible and safe and has few complications. Furthermore, the size of the implants used allows surgery to be performed in very young children.

Total Hip Arthroplasty for Acute Acetabular Fractures

Currently, a highly controversial topic remains the role, for a primary total hip arthroplasty to accompany an open reduction and internal fixation of selective acute displaced acetabular fractures, and especially in elderly and typically osteopenic individuals. A central theme of the controversy focuses on the realistic reconstruction of a displaced and comminuted fracture involving osteopenic bone and the likelihood to achieve a prolonged and favorable long-term clinical outcome for the arthroplasty.

Effects of Nandrolone and TGF-β1 in growing rabbits with osteopenia induced by over-supplementation of calcium and vitamin D3

The study was undertaken to find out the effects of over supplementation of dietary calcium and vitamin D3 on the mineralization of growing skeleton, taking rabbit as an animal model; further to study the effects of Nandrolone deconoate and TGF-beta1 on the mineralization of osteopenic bones. Twenty four New Zealand White rabbits of either sex, 60 day old, were randomly divided in 4 equal groups, A, B, C and D. The animals of groups B, C and D were administered with oral supplementation of calcium (2000 mg/kg of standard rabbit feed) and vit-D3 (1000 IU/kg of standard feed) for 60 days. The animals of group A were given standard ration without any supplementation. After 60 days, the Ca-vit.D3 supplementation was discontinued; and the animals of group C were administered with TGF-beta1 (10 ng, i.m.) once in every three days and animals of group D were given Nandrolone deconoate (10 mg, i.m.) once every week for 30 days, whereas in animals of group B, no treatment was given. All the animals were evaluated based on different observations like body weight, radiographic observations, circulating biochemical and hormone profile (plasma Ca, IP, AP, OC and iPTH) every 15 days up to 60 days after initiation of treatment. The results indicated that the body weight of rabbits in different groups increased gradually and steadily at different intervals till the end of observation period, however, the increase was non-significantly more in group D. The CI in group A increased gradually at different intervals; whereas in groups B, C and D, there was no appreciable increase in the CI during the period of Ca-vit.D3 supplementation, suggesting development of osteopenia. Treatment with TGF-beta1 did not increase the CI significantly, whereas Nandrolone treatment resulted in significant increase in the CI on days 45 and 60. The plasma Ca levels showed slight but gradual increase from day 0 to 60 in almost all groups. Subsequently also, there was no marked change at different intervals in groups A and B; however, significant reduction in plasma Ca was noticed in group C on 15(th) day and in group D on 60(th) day after initiation of treatment. Plasma IP levels in groups B and C showed a decreasing trend up to day 60. After discontinuation of Ca-vit.D3 supplementation, in group B, it further decreased to remain significantly lower on 15(th) day, and in groups C and D, it increased significantly on 60(th) post-treatment day. There was no significant change in the AP activity during the entire period of study in group A; whereas significant reduction in AP activity was measured on 30(th) and 60(th) days of treatment in groups B and C, and on 15(th) day of treatment in group D. Plasma iPTH values did not show any significant change at any interval during the first 60 days in all groups. On 30(th) and 60(th) days of treatment, the mean iPTH level remained significantly lesser in group B. In all groups treated with over supplementation of Ca and vit.D3, there was a non-significant increase in the plasma OC levels up to day 60; however, there was no significant difference between the groups. It can be concluded that additional supplementation of Ca and vit.D3 results in osteopenia in growing rabbits. Administration of Nandrolone helps to increase the mineral density in osteopenic bones, whereas TGF-beta1 does not seem to have positive effect on the skeletal mineralization.

Mechanical Comparison of 3.5 mm Broad Dynamic Compression Plate, Broad Limited‐Contact Dynamic Compression Plate, and Narrow Locking Compression Plate Systems Using Interfragmentary Gap Models

To compare (1) pullout properties between 3.5 mm cortical and locking screws, and (2) mechanical properties and gap displacements between the 3.5 mm broad limited-contact dynamic compression plate (LC-DCP), broad dynamic compression plate (DCP), and narrow locking compression plate (LCP), during axial loading of plate-stabilized diaphyseal fragments with an interfragmentary gap. In vitro mechanical testing of implanted polyurethane foam (PUF) hollow cylinders that simulated compact or osteopenic diaphyseal bone. (1) Five cortical and locking screws and (2) 4 PUF-plate constructs for each plate type; using high- and low-density (0.8 and 0.32 g/cm(3)) cylinders. (1) Screws were completely extracted at 5 mm/min. (2) Plated constructs were axially compressed at 300 N/s for 10 cycles from 5 to 355 N to determine gap displacement during physiologic loading, followed by single cycle increasing load to failure. Pullout properties were not different between screw types. All plate constructs had yield loads over 3 times trotting loads. Gap closure occurred with LC-DCP and DCP constructs, but not LCP constructs. LCP construct properties were most similar to LC-DCP and DCP construct properties in the low-density model. All plate systems sustained physiologic limb loads. Only LCP constructs maintained some gap integrity, although LC-DCP and DCP screws were placed in neutral position. The LCP system is more likely than LC-DCP and DCP systems, with neutrally positioned screws, to maintain a planned interfragmentary gap, although gap strains range from 0% to 15% across the 2 mm gap during a trot load.

Osteogenic differentiation of mesenchymal stem cells from osteopenic rats subjected to physical activity with and without nitric oxide synthase inhibition

Physical activity has potent and complex effects on bones. We hypothesized that physical activity has a positive effect upon osteopenic rat bones because it stimulates osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). We also postulated that local nitric oxide concentrations mediate the effects of physical activity on bones. The objective of this study was to investigate the osteogenic differentiation in vitro of MSCs from osteopenic female rats subjected to physical activity with and without nitric oxide synthase inhibition. We used MSCs from the femurs of Wistar female rats divided into six groups: Group 1, sham-operated (control); Group 2, sedentary osteopenic; Group 3, active osteopenic; Group 4, sham-operated with L-NAME; Group 5, sedentary osteopenic with L-NAME; and Group 6, active osteopenic with L-NAME. The cells were cultured at 37 °C and 5% CO 2. Cells were phenotypically characterized with anti-CD45, anti-CD90, anti-CD73, and anti-CD54 using a FACScan cytometer. MSCs were cultured in osteogenic medium for 7, 14 and 21 days. Alkaline phosphatase activity, the capacity of dimethylthiazol conversion in formazan crystals, collagen synthesis and the number of mineralized nodules were analyzed. The means of all of the variables were compared using the SNK test. MSCs did not express CD45 in 96.94% of the cells, but there was expression of CD73, CD54 and CD90 in 93.99%, 95.10% and 86.77% of the cells, respectively. MSCs from osteopenic rats showed less osteogenic differentiation. Surprisingly, physical activity increased the osteogenic differentiation of MSCs in osteopenic rats. Inhibition of nitric oxide synthase in vivo had a negative effect upon the osteogenic potential of MSCs from normal rats and from osteopenic rats subjected to physical activity. Our results suggest that nitric oxide stimulates MSCs osteogenic differentiation and that nitric oxide mediates the beneficial effects of physical activity upon MSCs osteogenic differentiation.

Effect of Bone Mineral Density and Parathyroidectomy on Fracture Risk in Primary Hyperparathyroidism

Bone mineral density is one parameter used to decide whether patients with primary hyperparathyroidism (PHPT) should undergo parathyroidectomy. However, the influence of bone mineral density and parathyroidectomy on subsequent fracture risk is unclear. The authors conducted a retrospective cohort study of patients with PHPT based on administrative discharge abstract data. The dual energy x-ray absorptiometry (DEXA) scan T-scores at the femur were collected by chart review, and 10-year fracture-free survival (FFS) was the main outcome measured. A total of 533 patients were identified, most of them > or = 50 years old (89%) and female (87%). Seventeen percent of the patients were black. Mean initial calcium, parathormone, and creatinine levels were 11.1 mg/dl, 116 pg/ml, and 0.9 mg/dl, respectively. Parathyroidectomy was performed in 159 (30%) patients, and 374 (70%) were observed. The 10-year FFS after PHPT diagnosis was 94% in patients treated with parathyroidectomy and 81% in those observed (p = 0.006). Compared to observation, parathyroidectomy improved the 10-year FFS by 9.1% (p = 0.99), 12% (p = 0.92), and 12% (p = 0.02) in patients with normal bones (T-score > or = -1.0), osteopenia (T-score < or = -1.0, > or = -2.5), and osteoporosis (T-score < -2.5), respectively. On multivariate analysis, parathyroidectomy was independently associated with decreased fracture risk (HR = 0.41; 95%CI 0.18, 0.93), whereas non-black race (HR = 2.94; 95%CI 1.04, 8.30) and T-score < -2.5 (HR = 2.29; 95%CI 1.08, 4.88) remained independently associated with increased fracture risk. Parathyroidectomy decreases the risk of fracture in patients with normal, osteopenic, and osteoporotic bones. The largest impact from parathyroidectomy is in patients with osteoporosis. The highest risk of fracture is in non-blacks and in patients with osteoporosis.

The Current Status of Locked Plating: The Good, the Bad, and the Ugly

Locked plate technology has evolved in an effort to overcome the limitations associated with conventional plating methods, primarily for improving fixation in osteopenic bone. The development of screw torque and plate-bone interface friction is unnecessary with locked plate designs, significantly decreasing the amount of soft tissue dissection required for implantation, preserving the periosteal blood supply, and facilitating the use of minimally invasive percutaneous bridging fixation techniques. The locked plate is a fixed-angle device because angular motion does not occur at the plate screw interface. The use of locked plate technology allows the orthopaedic surgeon to manage fractures with indirect reduction techniques while providing stable fracture fixation. The secure 'feel' of locked plates, ease of application, and the low incidence of complications noted in early clinical reports have contributed to the proliferation of this technology. Along with reports of clinical successes, as the use of fixed angle/locked plates has increased, clinical failures are being noticed. This review will focus on the biomechanics of locked plate technology, appropriate indications for its use, laboratory and clinical comparisons to conventional plating techniques, and potential mechanisms of locked plate failure that have been observed.

Effect of low-power gallium-aluminum-arsenium laser therapy (830 nm) in combination with bisphosphonate treatment on osteopenic bone structure: an experimental animal study

Laser therapy is able to modulate cell metabolism and accelerate the repair of fracture. Little attention has been given to the effect of laser on bone with osteopenia or osteoporosis. The purpose of our study was to verify the effect of laser therapy in combination with bisphosphonate on osteopenic bone structure. The 35 Wistar female rats used were divided into five groups: (1) sham-operation rats (control), (2) ovariectomized (OVX'd) rats with osteopenia, (3) OVX'd rats with osteopenia treated with laser, (4) OVX'd rats with osteopenia treated with bisphosphonate and (5) OVX'd rats with osteopenia treated with bisphosphonate and laser. Groups 3 and 5 were given daily 6 mg doses of bisphosphonate orally. Groups 4 and 5 underwent low level laser therapy [gallium-aluminum-arsenium (GaAlAs) laser, 830 nm, 50 mW and 4 J/cm(2)] on the femoral neck and vertebral segments (T13-L2). Both treatments were performed over an 8-week period. Rats from the osteopenic control and osteopenic + laser groups presented marked osteopenia. In the osteopenic + bisphosphonate group, the trabecular bone volume in vertebra L2 was significantly greater than in the osteopenic control group. Notably, in the association between laser and bisphosphonate, the trabecular bone volume was significantly greater in vertebrae L2 and T13 and was similar to that in the sham-operation control group. It was concluded that the laser therapy associated with bisphosphonate treatment was the best method for reversing vertebral osteopenia caused by the ovariectomy.

Determinants of bone mass, density and growth in growing dogs with normal and osteopenic bones

Survey radiographs of all the growing dogs aged up to 6 months, which were presented to the IVRI polyclinics during the 10 year period were screened to study the determinants of bone mass, density and growth. On the basis of clinical history and radiographic evaluation of long bones, the cases were categorizes as normal or osteopenic. The relative cortical density (RCD), cortical index (CI), diameter of bone at the distal metaphysis (DDFM) and the width of the growth plate (WFGP) were determined by taking the femur as a model bone in German shepherd, Doberman and Spitz breeds of dogs at different age groups. The results showed that RCD was the least in 0-2 month old normal growing dogs in all the breeds. As the age advanced up to 6 months the RCD increased 20-25% and at 6 months, Spitz and Doberman showed significant increase (P<0.05) in the RCD. In osteopenic bones, RCD remained less (25-50%) than that of normal animals at all age groups, and at 2-6 months of age, RCD in osteopenic bones was significantly lesser than in normal animals in GSD and Spitz breeds. The CI was also the least at 0-2 months of age in normal dogs. The CI increased about 50% at 4-6 months of age in GSD and Spitz. Whereas in Dob., there was no appreciable change in the CI at different age groups, and at 2-6 months it was significantly (P<0.05) lesser than that of Spitz. In osteopenic bones, the CI was 25-75% lesser than that of normal animals at different age groups, and at 4-6 months there was significant difference (P<0.05) between the normal and osteopenic bones in GSD and Spitz. The DDFM was the least in 0-2 month old normal growing dogs, and as the age advanced, it increased 10-20% up to 6 months. However, no significant difference in the DDFM was seen between breeds and also between the normal and osteopenic bones at different age groups. In normal animals, the WFGP was the highest in the early age, subsequently it reduced 50-75% and at the 4-6 months there was a significant decrease (P<0.05) in all breeds of dogs. And at the 4-6 months, there was significant (P<0.05) difference in the WFGP between breeds, it was the least in Spitz and maximum in Dob., suggesting faster growth plate closure in Spitz than in GSD and Dob. breeds. In osteopenic bones, WFGP was generally more than in normal animals, and at 4-6 months (about 3-5 times more) there was significant difference (p<0.05) between the normal and osteopenic bones in all breeds, indicating that physeal closure may be delayed in osteopenic bones. The results indicate that among different breeds Doberman breed has the least bone mass and may be more prone to osteopenia; whereas Spitz has the strongest bone.

Suture anchor fixation strength in osteopenic versus non-osteopenic bone for rotator cuff repair

Rotator cuff tears are increasing with age. Does osteopenic bone have an influence on the pullout strength of suture anchors? SPIRALOK 5.0 mm (DePuy Mitek), Super Revo 5 mm and UltraSorb (both ConMed Linvatec) suture anchors were tested in six osteopenic and six healthy human cadaveric humeri. Incremental cyclic loading was performed. The ultimate failure load, anchor displacement, and the mode of failure were recorded. In the non-osteopenic bone group, the absorbable SPIRALOK 5.0 mm achieved a significantly better pullout strength (274 N +/- 29 N, mean +/- SD) than the titanium anchor Super Revo 5 mm (188 N +/- 34 N, mean +/- SD), and the tilting anchor UltraSorb (192 N +/- 34 N, mean +/- SD). In the osteopenic bone group no significant difference in the pullout strength was found. The failure mechanisms, such as anchor pullout, rupture at eyelet, suture breakage and breakage of eyelet, varied between the anchors. The present study demonstrates that, in osteopenic bone, absorbable suture anchors do not have lower pullout strengths than metal anchors. In normal bone, the bioabsorbable anchor in this study even outperformed the non-absorbable anchor.

Hohlschraubenunterstützte Rahmencerclage zur internen Arthrodese bei ausgeprägter Osteoporose und -penie

Osteosynthesis of osteoporotic or osteopenic bone poses a considerable challenge for the surgeon, the type of osteosynthesis performed, and the osteosynthesis material employed. In osteoporotic and osteopenic bone, especially when circulation is decreased or sensitivity reduced, the principle of tension banding places great demands on the bone and surgeon since insufficient tightening of the wire results in inadequate immobilization while overtightening of the tension band can cause the wire to cut through the soft bone. This contribution describes a surgical technique, which prevents the wire from cutting through the bone. Cannulated screws are inserted vertically into the bone in the traction direction and the wire of the tension banding is passed through the cannulated screws. This ensures that the wire traction is distributed across the entire cross section of the bone. Thus, it is possible to completely tighten the tension band in osteopenic and osteoporotic bone. This technique is illustrated using the example of internal screw and tension band arthrodesis of the ankle joint, which achieved stable arthrodesis with weight bearing and recovered ambulation in a patient with pronounced diabetic foot syndrome and peripheral arterial occlusive disease.

Locking Compression Plate in Long Standing Clavicular Nonunions With Poor Bone Stock

Aim of our study was to evaluate the use of Locking Compression Plate (LCP) in patients with long standing nonunions of the clavicle with osteoporotic bones. There were a total of 11 patients. Surgery was performed for painful nonunion with shoulder dysfunction. Average time since injury was 6.9 months (3-39 months). Nonunions were stabilized by a 3.5-mm LCP, applied on the antero-inferior surface of the clavicular shaft. A six-hole LCP was used in eight cases. In three patients seven-hole LCP and in one patient eight-hole LCP was used. The fixation was supplemented by autogenous cancellous bone graft (except in hypertrophic nonunions). Patients were followed for a mean of 2.8 (1-3) years. The average time of radiologic union was 5.3 months (3-9 months). Union was achieved in all patients. Subjective clinical assessment was performed using the Disabilities of the Arm, Shoulder, and Hand functional score (DASH). The mean DASH score preoperatively was 42 (25-52) and postoperatively was 24 (11-34). Superficial infection and features of reflex sympathetic dystrophy were seen in one patient each. Long standing clavicular nonunion with osteopenic bone is a difficult problem to treat. Our study shows that LCPs can be an improved implant option with good fracture healing.

Pullout strength of suture anchors in comparison with transosseous sutures for rotator cuff repair

Suture anchors are increasingly gaining importance in rotator cuff surgery. This means they will be gradually replacing transosseous sutures. The purpose of this study was to compare the stability of transosseous sutures with different suture anchors with regard to their pullout strength depending on bone density. By means of bone densitometry (CT scans), two groups of human humeral head specimens were determined: a healthy and a osteopenic bone group. Following anchor systems were being tested: SPIRALOK 5.0 mm (resorbable, DePuy Mitek), Super Revo 5 mm (titanium, Linvatec), UltraSorb (resorbable, Linvatec) and the double U-sutures with Orthocord USP 2 (partly resorbable, DePuy Mitek) and Ethibond Excel 2 (non-resorbable, Ethicon). The suture anchors/double U-sutures were inserted in the greater tuberosity 12 times. An electromechanical testing machine was used for cyclic loading with power increasing in stages. We recorded the ultimate failure loads, the system displacements and the modes of failure. The suture anchors tended to bring about higher ultimate failure loads than the transosseous double U-sutures. This difference was significant in the comparison of the Ethibond suture and the SPIRALOK 5.0 mm-both in healthy and osteopenic bone. Both the suture materials and the SPIRALOK 5.0 mm showed a significant difference in pullout strength on either healthy or osteopenic bone; the titanium anchor SuperRevo 5 mm and the tilting anchor UltraSorb did not show any significant difference in healthy or osteopenic bone. There was no significant difference concerning system displacement (healthy and osteopenic bone) between the five anchor systems tested. The pullout strength of transosseous sutures is neither on healthy nor on osteopenic bone higher than that of suture anchors. Therefore, even osteopenic bone does not constitute a valid reason for the surgeon to perform open surgery by means of transosseous sutures. The choice of sutures in osteopenic bone is of little consequence anyway since it is mostly the bone itself which is the limiting factor.

Diabetes and osteoporotic fractures

In a recent study of bone mineral density and fracture burden in postmenopausal women, Ann Cranney and colleagues reported that most of the fractures in their study population occurred in women with normal or osteopenic bone mineral density.[1][1] The authors suggested that factors other than bone

Abduction pillow immobilization following hip surgery: A welcome alternative for selected patients

Studies have shown that when using a spica cast following hip surgery in children , there are associated complications such as soiling, pressure sores, and osteopenic fractures. Charts were retrospectively reviewed for all patients who had undergone hip surgeries by one surgeon at one institution between 1999 and 2005. The method of post-operative immobilization (spica cast or abduction pillow) and complications were recorded for each patient. There was a total of 32 patients. Of these, 11-all of whom had a diagnosis of developmental dysplasia of the hip-were treated using a spica cast. In the 21 patients treated in an abduction pillow, 4 (19%) were switched to a spica cast for the following reasons: (1) distal femoral fracture as a result of vigorous resuscitation during a choking episode, (2) parental preference, (3) for added immobilization over concern of implant loss of fixation, and (4) concern of migration of the hip, which again migrated after being changed to a spica cast and eventually required a pelvic osteotomy. It is our opinion that only one of these complications in the children treated with an abduction pillow (the case of possible implant migration) may have been avoided if the child had originally been placed in a spica cast. The child who was successfully resuscitated after a choking incident weeks after the surgery may have had a worse outcome if it had been in a spica cast. This incident occurred at home and the abduction pillow was easily and quickly removed to allow resuscitation. An abduction pillow is a welcome alternative to a spica cast following hip surgery for many patients with neuromuscular and syndromic conditions. However, in children with osteopenic bone at risk for implant failure and in children with unstable hip reductions, a spica cast may be preferable.

In Vivo and In Vitro Response to a Gelatin/α-Tricalcium Phosphate Bone Cement

We recently developed a new biomimetic calcium phosphate bone cement enriched with gelatin (GEL-CP) which exhibits improved mechanical properties with respect to the control cement (C-CP) and a good response to osteoblast-like cells. In this work, we have extended the investigation to primary culture of osteoblasts derived from normal (N-OB) and osteopenic (O-OB) sheep bones cultured on samples of GEL-CP, and their behavior was compared to that of cells cultured on C-CP as control. Cell morphology, proliferation, and differentiation were evaluated at 3 and 7 days. Preliminary in vivo tests were carried out onto critical size defects in the radius diaphysis of rats.

Occurrence and Pattern of Long Bone Fractures in Growing Dogs with Normal and Osteopenic Bones

A retrospective study was undertaken to record the occurrence and pattern of long bone fractures, and the efficacy of Intramedullary (IM) Steinmann pin fixing in growing dogs. All the records of growing dogs during a 10-year-period were screened to record the cause of trauma, the age and sex of the animal, the bone involved, the type and location of the fracture, the status of fixation, alignment, maintenance of fixation and fracture healing. The results were analysed and comparisons were made between growing dogs with normal and osteopenic bones. Among the 310 cases of fractures recorded, the bones were osteopenic in 91 cases (29%). Minor trauma was the principal cause of fracture in dogs with osteopenia (25%), and indigenous breeds were most commonly affected (38%). Fractures in dogs with osteopenic bones were most commonly recorded in the age group of 2-4 months (53%), whereas fractures in normal dogs were almost equally distributed between 2 and 8 months of age. Male dogs were affected significantly more often in both groups. In osteopenic bones, most fractures were recorded in the femur (56%), and they were distributed equally along the length of the bone. Whereas in normal bones, fractures were almost equally distributed in radius/ulna, femur and tibia, and were more often recorded at the middle and distal third of long bones. Oblique fractures were most common in both groups; however, comminuted fractures were more frequent in normal bones, whereas incomplete fractures were more common in osteopenic bones. Ninety-nine fracture cases treated with IM pinning (66 normal, 33 osteopenic) were evaluated for the status of fracture reduction and healing. In a majority of the cases (61%) with osteopenic bones, the diameter of the pin was relatively smaller than the diameter of the medullary cavity (<70-75%), whereas in 68% of the cases in normal bones the pin diameter was optimum. The status of fracture fixing was satisfactory to good in significantly more osteonormal (59%) than osteopenic dogs (42%). Fracture healing, however, was satisfactory in significantly more cases with osteopenic than normal bones. The appearance of callus was relatively early and the amount of bridging callus was relatively large in greater number of osteopenic bone fractures. Mal-union and non-union were recorded more often in osteopenic cases than in normal cases. However, the incidence of bone shortening and osteomyelitis was significantly higher in normal bones than in osteopenic bones.

Subantimicrobial Dose Doxycycline Effects on Osteopenic Bone Loss: Microbiologic Results

Based on microbiologic concerns, the safety of a 24-month regimen of subantimicrobial dose doxycycline (SDD; 20 mg twice a day) was evaluated in postmenopausal osteopenic women with periodontitis in a double-blind, placebo-controlled, randomized clinical trial. Subgingival samples were collected from two sites (probing depth > or = 5 mm) in each of 128 subjects at baseline, with the same sites resampled at the conclusion of the 2-year period. The samples were enumerated on selective and non-selective media and on doxycycline (4 microg/ml) medium. Up to five different colonial morphologies were subcultured from the doxycycline medium, identified to species, and susceptibilities determined to doxycycline and five other antibiotics. Data were analyzed for microbial differences in total colony forming units (CFU), periodontal and opportunistic pathogens, and changes in species and in susceptibilities of isolates recovered on doxycycline medium. There was no significant evidence that changes in total anaerobic counts over the treatment period (P = 0.96) differed between treatment groups. Likewise, periodontal pathogens, opportunistic pathogens, or normal flora did not differ descriptively between groups. Although there was a significant increase (P <0.001) in the total CFU recovered from the 4 microg/ml doxycycline plates at 24 months for SDD versus placebo, the percentage that was clinically resistant to doxycycline (minimal inhibitory concentration [MIC] > or = 16 microg/ml) decreased over the 24-month period in both groups and did not differ between the treatment groups (SDD: 79% to 76%; placebo: 83% to 70%; P = 0.2). There were no significant differences (P >0.28 for each) in the change in cross-resistance between the groups for doxycycline and the other five antibiotics. No antimicrobial effect on the subgingival flora was detected following treatment with SDD for 24 months, relative to baseline or to placebo. The increase in initial resistance (at 4 microg/ml) did not translate into a significant increase in the percent resistant to doxycycline (MIC > or = 16 microg/ml) for patients in the SDD group.

Plating in Proximal Humeral Fractures.

Improved imaging, updated knowledge regarding humeral head perfusion and adapted fixation techniques with implants having better purchase also in osteopenic bone, have influenced the treatment of proximal humeral fractures in recent years. Demographic evolution and a more active population even among the older age groups will increase the incidence of this fracture, which is already the third most frequent fracture after hip and distal radius fractures in elderly patients. Long-term morbidity related to the treatment of these fractures like avascular humeral head necrosis, non-union, malunion, shoulder stiffness, persistent pain and functional disability are the challenging factors to be overcome. Plate osteosynthesis with angular stable implants have shown to address some of these problems and to broaden the spectrum of indication towards anatomic fracture stabilization even for severely displaced three- and four-part fractures instead of replacing the humeral head with an endoprosthesis, as long as a stable fixation is possible. Open access surgery is often needed for anatomic reconstruction of complex and displaced fractures. This calls for immediate postoperative mobilization with active-assisted ROM exercise to prevent subdeltoidal adhesions. Even though plating of proximal humeral fractures with angular stable implants has shown promising first clinical results, there still remain elevated complication rates especially in the elderly osteoporotic patient population. Recent clinical reports using angular stable plates provided only data with a low level of evidence to help in decision-making. The comparison with historical series using non-angular stable plates in respect to the long-term morbidity should help to better evaluate the value of locked plates inserted with less-extensive soft-tissue exposure.

Bone homing of mesenchymal stem cells by ectopic α4 integrin expression

The pluripotent nature of mesenchymal stem cells (MSC) widens their potential for tissue regeneration and as vehicles for cell therapy in molecular medicine. Although the MSC are relatively easier to obtain and propagate in culture, a major impediment remains in their engraftment to target tissues on autologous transfer. We report here that transient, ectopic expression of alpha4 integrin (CD49d) on MSC greatly increases bone homing in an immunocompetent mouse model. Heterodimerization of the alpha4 integrin with endogenous beta1 integrin (CD29) was confirmed to influence this targeting. In addition to retaining their stem cell property, the engrafted MSC were also found to form osteoblasts and osteocytes in the growth plate of recipient mouse limb bones (femur/tibia) in vivo. These findings provide evidence for a novel strategy to achieve bone homing of genetically engineered MSC, which may broadly benefit in targeted therapies for osteopenic bone defects and cancer bone metastasis.