Osteointegration of an uncemented modular revision stem implanted during revision hip surgery.

BACKGROUND: Though mid-term survival rates of over 95% in several series have been published, there is still a paucity of related literature regarding the role of vertical stem instability in the osteointegration of fluted tapered stems. This paper presents a comprehensive and prospective assessment on short-term experiences with uncemented modular femoral stem in the treatment of defective femur during revision surgery of total hip replacement. MATERIALS AND METHODS: Clinical and radiological monitoring of 20 consecutive patients with implanted tapered fluted revision stem (Lima Corporate, Udine, Italy) was of 27 months in average (20-35 months). The average pre-operative Merle d'Aubigné and Postel method score was 6.3 points (3-10 points). The frequency of femur defects, classified according to Paprosky, was IIIA = 9 and IIIB = 11. RESULTS: During last follow-up, the Merle d'Aubigné and Postel hip score was on average 11.7 (6-16 points). Compared to post-operation radiograph, stem migration of 1.9 mm (0-11 mm) on average was found. This vertical stem migration was observed only when comparing hip radiographs immediately after surgery, and at 6 weeks post-surgery. The Paprosky IIIA defects group, presented a subsided stem by an average of 1.5 mm. In the group of Paprosky IIIB defects, the stem subsidence was on average 2.3 mm. All 20 patients in the study showed excellent osteointegration of the uncemented revision modular stem. CONCLUSIONS: This study found and excellent osteointegration of the Lima uncemented tapered fluted revision modular stem in defective femur with a cortical bone segment present in the diaphyseal isthmus area. The initial vertical instability leading to stem migrating during the first six weeks following surgery did not, however, affect its osteointegration.

Histological assessment of tissue from large human bone defects repaired with ß-tricalcium phosphate.

This report describes the histological characteristics of large human bone defects that were implanted with ß-tricalcium phosphate (ß-TCP). Samples were obtained longer after the primary operation than in the earlier studies. We assessed a total of nine biopsies taken 33-208 weeks after implantation. The tissue sections were stained with hematoxylin-eosin for general observation, with Gomori stain to visualize the reticulin fibers, and with an antibody against tartrate-resistant alkaline phosphatase (TRAP) to characterize the cells. Ongoing bone remodeling was observed even 208 weeks after implantation as determined by the presence of osteoclasts and active osteoblasts and new woven and lamellar bone. We observed multinuclear giant cells phagocytosing the biomaterial and the attachment of osteoclasts to the ß-TCP. The osteoclasts showed intense TRAP positivity, while the giant cells showed variable TRAP positivity. There was a zonal pattern in the original defects: The central regions showed granules and fibrous septa, while peripheral areas showed a layer of new bone formation. These data demonstrate ongoing bone remodeling long after implantation in the peripheral regions of the original defects as well as fibrous changes in the central regions and phagocytosis of biomaterial by multinuclear giant cells.

In vivo behaviour of low-temperature calcium-deficient hydroxyapatite: comparison with deproteinised bovine bone.

This study aims to evaluate in detail the biological osteoconductive properties of the low-temperature synthetic porous calcium-deficient hydroxyapatite and to compare it with the biological apatite. Bone reactions to granules of similar sizes of the low-temperature hydroxyapatite and commercially available non-sintered deproteinized bovine bone were compared. Two different temperatures were used to fabricate two batches of newly developed porous hydroxyapatite with different carbonate groups content and specific surface area. The histological analysis of specimens with histomorphometry was performed at different time after in vivo implantation. Based on histological analysis, the level of bone formation in the spaces between the implanted granules and through the interconnected pores of all implanted materials within a cortical region (bone area ingrowth 72-85 %) was several-fold higher than within a cancellous bone site (bone area ingrowth 16-28 %) at three and six months after implantation. Within the cancellous bone site, bone coverage of the implanted material at six months was significantly higher in hydroxyapatite material fabricated using low-temperature synthesis and subsequent processing at 150°C than in hydroxyapatite scaffold developed using low-temperature synthesis with subsequent processing at 700°C or deproteinized bovine bone. According to our study, the bioactive properties of the low-temperature calcium-deficient hydroxyapatite are comparable with the biological apatite. The favourable influence of a high specific surface area of a low-temperature calcium-deficient hydroxyapatite on in vivo bone formation was emphasized.

Comparative outcomes of total knee arthroplasty on physically active and passive patients.

The physical activity of the population is decreasing due to an increase in sedentary lifestyles. The aim of the study was to analyze midterm results of total knee arthroplasty according to the lifelong physical activity of the patients. We evaluated 37 patients (23 women, 14 men), with age average 70.0 years (range 53-87). We divided the patients according to lifelong physical activity. The active group included 11 patients with any history of physical activity and the passive included 26 patients with a sedentary lifestyle. No intergroup differences existed in age, gender or preoperative Knee Score. The active group had a higher postoperative Knee Score 90.5 (+/- 5.0) compared to the passive 87.4 (+/- 5.0). Pain after arthroplasty was experienced significantly more in the active group. Between the active 87.3 (+/- 9.3) and passive 67.5 (+/- 16.7) groups we measured a statistically significant difference in the improvement of Functional Score - ability to walk and climb stairs. Sedentary lifestyle affects the clinical outcomes of total knee arthroplasty. This data is demonstrating that physical activity ameliorate functional postoperative results.

Methotrexate released in vitro from bone cement inhibits human stem cell proliferation in S/G2 phase.

Methotrexate (MTX) released from bone cement showed a useful local effect in animal models of bone tumours. However, local toxic reactions such as impaired wound healing were observed in areas surrounding the MTX-loaded implant. Therefore, we hypothesised that MTX released from bone cement would have harmful effects on human mesenchymal stem cells (MSC)-one of the basic components of bone marrow and tissue reparatory processes. Moreover, elution of MTX was calculated from implants prepared either with liquid or powdered MTX. During the 28-day incubation, the cement compounded with liquid MTX showed the highest elution rate of the drug. MTX released from pellets produced a significant decrease in proliferation of MSC as a consequence of a blockade of their cell cycle in the S/G2 phase. These findings indicate impairment of stem cell function in marginal areas surrounding the MTX-loaded cement and may help to explain problems with regeneration of tissues in these locations.

Behaviour of nonresorbable bioactive glass-ceramic implanted into long bone defects: comparison with cancellous allografts.

INTRODUCTION: The goal of this retrospective study was to compare the long-term results after implantation of the nonresorbable glass-ceramic material and transplantation of the cancellous allografts into the defects of long bones. METHOD: The bone cysts were excochleated and filled using granules of glass-ceramic material or cancellous allografts. Clinical, radiographic and scintigraphic examinations of 30 patients were carried out 2-14 years after their surgery. RESULTS: Though signs of complete incorporation allowing full weight-bearing capacity were observed on plain radiographs, we detected pain in six out of nine patients after diaphyseal implantation of nonresorbable glass-ceramic. We found an increase in (99) (m)Tc-methylene diphosphonate uptake on the delayed images in the area of glass-ceramic implantation, mainly in its diaphyseal location. In patients after bone transplantation, the cancellous allografts were completely integrated and the scintigraphic findings were physiological. CONCLUSION: The implantation of the nonresorbable glass-ceramic material into the diaphyseal defects of long bones is not suitable based on our study.

Secondary stability assessment of titanium implants with an alkali-etched surface: a resonance frequency analysis study in beagle dogs.

PURPOSE: This study was carried out to quantify the effect of an alkali-modified surface on implant stability during healing using an animal model. MATERIALS AND METHODS: A total of 24 screw-shaped, self-tapping, commercially pure titanium dental implants, divided into a test group (implants with an alkali-modified surface or "biosurface") and a control group (implants with a turned, machined surface) were inserted without pretapping in the tibiae of 3 beagle dogs. The resonance frequency analysis method was used to measure the implant stability quotient (ISQ) 0, 1, 3, 9, and 12 weeks after implantation. The animals were sacrificed after 2, 5, and 12 weeks, and the bone-implant contact (BIC%) was evaluated histomorphometrically. RESULTS: The difference in the osseointegration rates (deltaISQ/deltahealing time) between the implants with alkali-modified surface (biosurface) and those with a turned, machined surface was evaluated as a mean of 0.843 ISQ/week within the first 9 weeks of healing. The mean increase in the secondary implant stability was found to be proportional to the mean increase in the BIC at healing period earlier than 5 weeks. DISCUSSION: The characteristics that differed between the implant surfaces, ie, specific surface area, contact angle, and hydroxylation/hydration, may represent factors that influence the rate of osseointegration and the secondary implant stability. CONCLUSION: The alkali-treated surface enhances the secondary stability in the early stages of healing compared to the turned, machined surface, as a consequence of faster BIC formation.

Comparative Study on the Application of Mesenchymal Stromal Cells Combined with Tricalcium Phosphate Scaffold into Femoral Bone Defects.

This prospective study sought to evaluate the healing quality of implanted ultraporous ß-tricalcium phosphate sown with expanded autologous mesenchymal stromal cells (MSCs) into femoral defects during revision hip arthroplasty. A total of 37 osseous defects in 37 patients were treated and evaluated concerning bone regeneration. Nineteen subjects received ß-tricalcium phosphate graft material serving as a carrier of expanded autologous MSCs (the trial group A), nine subjects received ß-tricalcium phosphate graft material only (the study group B) and nine subjects received cancellous allografts only (the control group C). Clinical and radiographic evaluations were scheduled at 6 weeks, 3, 6, and 12 months post-operatively, and performed at the most recent visit as well. All observed complications were recorded during follow-up to assess the use of an ultraporous ß-tricalcium phosphate synthetic graft material combined with expanded MSCs in bone defect repair. The resulting data from participants with accomplished follow-up were processed and statistically evaluated with a Freeman-Halton modification of the Fischer's exact test, a P < 0.05 value was considered to be significant. Whereas no significant difference was observed between the trial group A with ß-tricalcium phosphate synthetic graft material serving as a carrier of expanded autologous MSCs and control group C with cancellous impaction allografting in terms of the bone defect healing, significant differences were documented between the study group B with ß-tricalcium phosphate graft material only and control group C. Regarding adverse effects, six serious events were recorded during the clinical trial with no causal relationship to the cell product. ß-tricalcium phosphate synthetic graft material serving as a carrier of expanded autologous MSCs appears safe and promotes the healing of bone defects in a jeopardized and/or impaired microenvironment. This clinical trial was registered at the EU Clinical Trials Register before patient recruitment (Registration number: EudraCT number 2012-005599-33; Date of registration: 2013-02-04).

Grade-III slipped capital femoral epiphysis with unstability: a report of three cases.

We reviewed the cases of three patients with an unstable grade-III slipped capital femoral epiphysis treated between 2001 and 2003. Clinical records and imaging studies were reviewed for patient's history, anatomic features of the slip, definitive treatment and clinical outcome. The duration of the follow-up ranged from twenty-four to fourty-eight months.

Utilizing Autologous Multipotent Mesenchymal Stromal Cells and ß-Tricalcium Phosphate Scaffold in Human Bone Defects: A Prospective, Controlled Feasibility Trial.

The purpose of this prospective controlled study was to compare healing quality following the implantation of ultraporous ß-tricalcium phosphate, containing either expanded autologous mesenchymal stromal cells (trial group, 9 patients) or ß-tricalcium phosphate alone (control group, 9 patients), into femoral defects during revision total hip arthroplasty. Both groups were assessed using the Harris Hip Score, radiography, and DEXA scanning at 6 weeks and 3, 6, and 12 months postoperatively. A significant difference in the bone defect healing was observed between both groups of patients (P < 0.05). In the trial group, trabecular remodeling was found in all nine patients and in the control group, in 1 patient only. Whereas, over the 12-month follow-up period, no significant difference was observed between both groups of patients in terms of the resorption of ß-tricalcium phosphate, the significant differences were documented in the presence of radiolucency and bone trabeculation through the defect (P < 0.05). Using autologous mesenchymal stromal cells combined with a ß-tricalcium phosphate scaffold is a feasible, safe, and effective approach for management of bone defects with compromised microenvironment. The clinical trial was registered at the EU Clinical Trials Register before patient recruitment has begun (EudraCT number 2012-005599-33).

Charcot arthropathy of the knee. A case-based review.

The diagnosis of Charcot arthropathy in the knee is rare. However, there is an increasing number of diabetic patients, and they are living longer due to improvements in treatment. Because neuropathic arthropathy is a late effect of peripheral neuropathy, we can expect an increasing incidence of neuropathic arthropathy. Total knee arthroplasty is the preferred choice of treatment by patients, although it may also be associated with a high incidence of serious complications. This case report presents a young female with diabetes mellitus and Charcot arthropathy of the knee managed by total knee arthroplasty and a literature review. The report encompasses a 5-year follow-up of the patient, from the first contact after knee distortion through diagnosis of Charcot arthropathy and the performance of total knee arthroplasty with outpatient controls. The diagnosis was established on the basis of the rapid destruction of the medial tibial condyle after knee distortion in a patient with neuropathy. Neuropathic arthropathy was confirmed by histology. The patient refused knee fusion and total knee arthroplasty was performed. The patient quickly achieved a painless, stable knee with a 130-degree range of motion. However, a radiolucent line appeared under the tibial component due to premature weight-bearing. The patient was ordered to refrain from weight-bearing for the next 3 months, and the knee was healed. While the management of Charcot arthropathy in the knee remains controversial, total knee arthroplasty is not a contraindication. Early diagnosis, appropriate choice of implant and operative technique, and long-term weight protection are essential.

Behavior of bioactive glass-ceramic implanted into long bone defects: a scintigraphic study.

The purpose of the study was to assess the long-term behavior and incorporation of the bioactive oxyhydroxyapatite glass-ceramic used to fill defects of long bones after curettage of bone cysts in 17 patients. The method of evaluation was a three-phase bone scintigraphy combined with radiographic and clinical evaluation. At a mean follow-up of 7 years, the glass-ceramic material had been completely incorporated. Mean uptake ratio was 1.31+/-0.25 after implantation of glass-ceramic in the metaphyseal region and 2.07+/-0.62 after implantation of glass-ceramic in the diaphyseal region (P<0.05). Mean uptake ratio was 1.40+/-0.30 in patients without persistent pain and 2.07+/-0.69 in patients who complained of pain in the area of synthetic filling (P<0.05). The bioactive glass-ceramic can be implanted into the metaphyseal defects of long bones, but this material is not suitable for filling the diaphyseal defects.