Occlusal loading and muscle forces during mastication aids in assessment of dental restorations and implants and jaw implant design; however, three-dimensional bite forces cannot be measured with conventional transducers, which obstruct the native occlusion. The aim of this study was to combine accurate jaw kinematics measurements, together with subject-specific computational modelling, to estimate subject-specific occlusal loading and muscle forces during mastication.

Motion experiments were performed on one male participant (age: 39yrs, weight: 82kg) with healthy dentition. Two low-profile magnetic sensors were fixed to the participant's teeth and the two dental arches digitised using an intra-oral scanner. The participant performed ten continuous of chewing on a polyurethane rubber sample of known material properties, followed by maximal compression (clenching). This was repeated at the molars, premolars of both the left and right sides, and central incisors. Jaw motion was simultaneously recorded from the sensors, and finite element modelling used to estimate bite force. Specifically, simulations of chewing and biting were performed by driving the model using the measured kinematics, and bite force magnitude and direction quantified. Muscle forces were then evaluated using a rigid-body musculoskeletal model of the patient's jaw.

The first molars generated the largest bite forces during chewing (left: 309 N, right: 311 N) and maximum-force biting (left: 496 N, right: 495 N). The incisors generated the smallest bite forces during chewing (75 N) and maximum-force biting (114 N). The anterior temporalis and superficial masseter muscles had the largest contribution to maximum bite force, followed by the posterior temporalis and medial pterygoid muscles.

This study presents a new method for estimating dynamic occlusal loading and muscle forces during mastication. These techniques provide new knowledge of jaw biomechanics, including muscle and occlusal loading, which will be useful in surgical planning and jaw implant design.

Total temporomandibular joint (TMJ) replacements reduce pain and improve quality of life in patients suffering from end-stage TMJ disorders, such as osteoarthritis and trauma. Jaw kinematics measurements following TMJ arthroplasty provide a basis for evaluating implant performance and jaw function. The aim of this study is to provide the first measurements of three-dimensional kinematics of the jaw in patients following unilateral and bilateral prosthetic TMJ surgeries.

Jaw motion tracking experiments were performed on 7 healthy control participants, 3 unilateral and 1 bilateral TMJ replacement patients. Custom-made mouthpieces were manufactured for each participant's mandibular and maxillary teeth, with each supporting three retroreflective markers anterior to the participant's lip line. Participants performed 15 trials each of maximum jaw opening, lateral and protrusive movements. Marker trajectories were simultaneously measured using an optoelectronic tracking system. Laser scans taken of each dental plate, together with CT scans of each patient, were used to register the plate position to each participant's jaw geometry, allowing 3D condylar motion to be quantified from the marker trajectories.

The maximum mouth opening capacity of joint replacement patients was comparable to healthy controls with average incisal inferior translations of 37.5mm, 38.4mm and 33.6mm for the controls, unilateral and bilateral joint replacement patients respectively. During mouth opening the maximum anterior translation of prosthetic condyles was 2.4mm, compared to 10.6mm for controls. Prosthetic condyles had limited anterior motion compared to natural condyles, in unilateral patients this resulted in asymmetric opening and protrusive movements and the capacity to laterally move their jaw towards their pathological side only. For the bilateral patient, protrusive and lateral jaw movement capacity was minimal.

Total TMJ replacement surgery facilitates normal mouth opening capacity and lateral and inferior condylar movements but limits anterior condylar motion. This study provides future direction for TMJ implant design.

Osteochondral lesions (OCL) of the talus occur in 38% of the patients with supination external rotation type IV ankle fractures and 6 % of ankle sprains. Osteoarthritis is reported subsequently in 8–48% of the ankles. Several marrow stimulation methods have been used to treat the symptomatic lesion, including arthroscopic debridement and micro fracture. Encouraging midterm results have been reported, but longterm outcome is unknown in relation to more invasive treatments such as transfer of autologous osteoarticular tissue from the knee or talus (OATS), autologous chondrocyte implantation (ACI), frozen and fresh allograft transplantation.

Hind and mid foot arthritis is often noted in patients who have previously had an ankle arthrodesis. It has been suggested that this arthritis may be precipitated or exacerbated as a direct result of the ankle fusion. The aim of this study was to investigate the degree and pattern of pre-existing ipsilateral foot arthritis in patients who have subsequently undergone ankle arthrodesis.

A retrospective review of the most recent pre-operative radiographs of 70 patients who underwent 71 arthrodeses between 1993-2003 was performed. Patients with rheumatoid disease were excluded. The immediate pre-operative AP and lateral ankle radiographs were assessed and the presence and severity of osteoarthritis for the sub-talar, talo-navicular, naviculo-cuneiform and calcaneo-cuboid joints was recorded using the Kellgren and Lawrence grading score. This was performed simultaneously by two reviewers and a consensus obtained. A total score out of 16 was given for each radiograph.

68 (96%) of the radiographs reviewed showed evidence of pre-existing hind or mid foot arthritis prior to ankle fusion. The sub-talar joint was the most commonly and severely affected. The median total arthritis score for each radiograph was 5. There was no association between age or causative pathology and the degree of arthritis.

This study has demonstrated that hind and mid foot arthritis is very common in patients with co-existent ankle arthritis prior to ankle fusion. This has previously been assumed to have developed as a result of the surgery but is, in fact, present at the time of the operation and this needs to be taken into consideration when evaluating the results of ankle arthrodesis

Introduction

Scaphoid fracture is the most common undiagnosed fracture. Occult scaphoid fractures occur in 20-25 percent of cases where the initial X-rays are negative. Currently, there is no consensus as to the most appropriate investigation to diagnose these occult frctures. At our institution MRI has been used for this purpose for over 3 years. We report on our experience and discuss the results.

Background: To our knowledge, a prospective randomised study comparing blood loss in cemented and uncemented total knee replacement has not been performed.

Method: From 1994 to 2004, 205 consecutive patients (78 men and 128 women) undergoing total knee replacement were randomised to one of the two groups, one using a cemented Kinnimax prosthesis and the other an uncemented LCS knee prosthesis. In 96.1% of the patients the procedures were performed for osteoarthritis whilst 3.9 % for RA. All patients had their haemoglobin and heamatocrit recorded preoperatively and postoperatively. The patient’s height, weight and body mass index were recorded preoperatively. The red blood cell (RBC) volume loss were measured by an indirect method which involved calculations using height, weight and pre op and post op heamatocrit.

Results: The mean red cell volume loss in uncemented knees (0.46lts) was significantly greater than the loss in cemented knees (0.39lts) p = 0.015. There was no statistically significant difference in relation to preoperative deformity, approach or ASA grade.

Conclusion: Our study concludes that the uncemented knees loose more blood compared to cemented knees. There have been smaller studies looking at this, but we believe this to be the largest and most comprehensive to date.

Background: To our knowledge, a prospective randomised study comparing blood loss between cemented and uncemented total knee replacement has not been performed.

Method: From 1994 to 2004, 205 consecutive patients (78 men and 128 women) undergoing total knee replacement was randomised to one of the two groups, cemented Kinnimax or uncemented LCS knees. 96.1 % of the procedures were performed for osteoarthritis whilst 3.9 % for RA. All patients had haemoglobin and heamatocrit recorded preoperatively and postoperatively. Each patients height, weight and body mass index were recorded preoperatively. The red blood cell (RBC) volume loss was measured using an indirect method which involved calculations using height, weight and pre op and post op haematocrit. The mean post operative RBC volume in cemented knees was 1.32lts whilst that of uncemented knees was 1.38lts; p value – 0.202.

Results: The mean red cell volume loss in cemented knees was 0.39lts and that of uncemented knees was 0.45lts, p value 0.015 which was statistically significant. There was no statistically significant difference in relation to preoperative deformity, approach or ASA grade. There was statistically significant increase in tourniquet time in cemented knees.

Conclusion: Our study concludes that the uncemented knees loose more blood compared to cemented knees. There have been smaller studies looking at this, but we believe this to be the largest and most comprehensive to date.

We wanted to verify the validity of the treatment of vertebroplasty and kyphoplasty to failure of the anterior column of the thoracic and lumbar spine.

Since 2002, 39 procedures of vertebroplasties and kypholasties were performed to 36 patients.

Most of the procedures were done because of painful ostoporotic fractures. 4 were because of metastasis, 2 hemangiomas of the vertebral body. 2 multiple myeloma. One Paget disease of bone.

In cases of multiple osteoporotic fractures, decision was made based on clinical Findings and bone scan.

Results were encouraging: 31 patients reported of improvement of pain. Analyzing Visual Analogue Score, alleviation was recorded immediately after surgery.

Few complications were registered: 2 patients underwent further surgery because of radiating pain. In two patients malpositioning of the Vertebral Body Reconstraction was seen. One patient had osteomyelitis of the vertebral body. 2 cement leakage were seen.

Vertebroplasty and kyphoplasty are good solutions for the treatment of failure of the anterior column in the thoracic and lumbar spine. Accurate patients election should be done in order to detect patients with spinal stenosis that will respond negatively to this treatment.

Purpose: Numerous implants used in repairing a trochanteric fracture of the hip are currently available. The purpose of this prospective study was to determine the complications and results of the percutaneous compression plate (PCCP), a relatively new device versus the conventional dynamic hip screw (DHS).

Materials and Methods: Between 2001–2003, 110 consecutive patients with trochanteric fractures were treated in our department. Fifty-five fractures were stabilized using the PCCP and 55 fractures were treated with the DHS. Results were analyzed according to fracture pattern, type of implant, quality of fracture reduction and position of implant. Function was assessed on the basis of pain, walking aids and walking capability.

Results: Forty-seven (85%) of 55 hips treated with PCCP healed without additional treatment and complications. Forty-three (78%) treated with DHS healed without additional treatment and complications. Complications among 8 patients (15%) of the PCCP group were: deep vein thrombosis, cardiac complication, chest infection and pressure sores. Complications among 12 patients (22%) of the DHS group were: implant failure (7%), deep wound infection, deep vein thrombosis and pressure sores.

Conclusions: Use of the PCCP implant provides similar and occasionally better results compared to those obtained with the conventional DHS device. The most outstanding advantage of the PCCP device was no implant failure or implant cut out.

Purpose: Glucosamine-based massage cream has been developed by an Israeli company (Manon Pharmaceuticals). Prior literature indicates that a single study performed about 30 years ago has demonstrated a certain efficacy of a glucosamine containing topical formulation for the treatment of gonarthrosis.

Materials and Methods: Eighty patients suffering from grade 2–3 degenerative changes of the knee were randomized and received either a menthol based cream or a glucos-amine-containing formulation. The study was approved by the institutional Helsinki committee. Patients were evaluated pre treatment using the VAS pain measure as well as the KSS score. Standardized radiographs were evaluated as described by Ahlbeck to evaluate the stage of articular cartilage degeneration. Exclusion criteria were grade 1 and 4, inflammatory arthritis and Charcot arthropathy. Patients employed the massage cream on a tid basis for a minimum of one month. Patients were followed for a minimum of 6 months. Medication usage was evaluated during follow-up.

Results: Improvement was noted in 32 of 40 patients (defined as VAS improvement by 20 percent or more) of the experimental group and in 12 of 40 patients of the control group. KSS scores improved in 21 of 40 patients of the experimental group by 5 points or more at the 6 months time-point. Only 5 patients in the control group demonstrated similar improvement.

Conclusions: Some improvement is noted in symptoms by the use of topically applied glucosamine- containing massage cream in knee arthrosis. However many questions remain un-answered. What is the mechanism of action of topically applied glucosemamine? Does it penetrate skin and capsule to reach the cartilage and synovium? What is the role of the placebo effect in the treatment of joint symptoms in osteoarthritis, a disease typified by an undulating clinical course.

Purpose: Total knee arthroplasty has been established as a reliable treatment modality for advanced gonarthrosis. Satisfactory outcome depends on restoration of the neutral alignment of the leg. Our study evaluates whether computer-assisted navigated knee arthroplasty achieves a more accurate knee alignment.

Materials and Methods: In a prospective study two groups of 24 patients undergoing TKA had operations using either a computer-assisted navigation system or a conventional technique. Limb alignment and component orientation were determined on post-operative coronal and lateral X-rays.

Results: In our study the post operative axis of the thumb was significantly better in the computer-assisted group (94%, within ±3^° varus/valgus) compared with the conventional group (82%, within ±3° varus/valgus). A significantly better orientation of the femoral and the tibial components was achieved in the computed-assisted navigated group.

Conclusions: Computer-assisted navigated TKA gives better correction of leg alignment and components orientation as we saw in the computer-assisted navigated group. Potential benefits in the long-term outcome and functional improvement require further investigation.

Purpose: Conducting a prospective study comparing the short-term results of minimally invasive total knee replacement surgery using a conventional prosthesis (i.e. not specifically designed for minimally invasive surgery – MIS, AGC Biomet) with knee arthroplasties performed via a transvastus approach.

Operative Technique: MIS knee arthroplasty is performed via a medial parapatellar skin incision from the supero-medial pole of the patella to the tibial tuberosity. The major difference is the lack of quadriceps muscle dissection and the lack of patellar inversion. The instruments fit into the incision, though some of the pins have to be inserted percutaneously. In order to reduce patello-femoral pressure and pain, an osteophytectomy is performed followed by sawing a slice of the patella and denervation using a diathermy. The wound is closed with intra-dermal sutures and a drain is not used.

Materials and Methods: Forty-five consecutive knee replacements were randomized into either a conventional trans-vastus approach (22 patients) or a minimally invasive procedure (23 patients). The patients were assessed using an HSS knee score, a VAS score and knee range of motion every day during hospitalization was recorded separately. Blood consumption and length of hospitalization were recorded as well. The patients were followed for a minimum of 3 months. Radiographic evaluation included prosthesis alignment in the AP and lateral views.

Results: Pre-op age, sex, VAS score and HSS were similar in both groups. Initial limb alignment averaged 9 degrees of varus in both groups. Pre-op range of motion was similar in both groups -5 degrees of extension and 90 degrees of flexion. Operative time was similar in both groups. Length of hospital stay was similar in both groups. Blood usage was diminished in the MIS group by an average of 0.8 units.

At the 2-weeeks and 6-weeks time-point the range of motion in the MIS group was better both in flexion and in extension by an average of 20 degrees, than in the conventional surgery group. This difference was nullified at the 3 months time-point. Radiographic alignment was similar in both groups. The limb alignment post-op averaged 3 degrees of varus.

Conclusions: MIS knee arthroplasty appears to yield similar results to conventional arthroplasty regarding prosthesis alignment and hospitalization.

Aim

To assess the results of arthroscopic treatment of osteochondral lesions of the talus and identify factors associated with a poor outcome.

Materials and Methods

Sixty patients (44 male, 16 female) with an average age at operation of 34 years(14 to 72 years) were reviewed after an average of 42 months(6 to 99 months). Patients were graded according to the criteria of Berndt and Harty1. Pre-operative radiographs and MRIs were graded according to Anderson et al2 and Hepple et al3 respectively. Forty-one lesions were medial, 31 of which were traumatic and 19 were lateral, all of which were traumatic. Thirty-four patients were treated with excision and curettage, 22 by excision and drilling, 2 by internal fixation and 2 by bone grafting.

Results

Thirty-one patients achieved a good outcome, 16 fair and 13 poor. Of the 13 poor results, 12 were medial lesions. Medial lesions presented later than lateral lesions (three years compared with 18 months) and almost 50% demonstrated cystic change on radiographs and MRI whereas only one lateral lesion demonstrated such changes. Outcome was not associated with patient age and no difference was found between traumatic and atraumatic medial lesions.

Conclusion

Most osteochondral lesions are well served by conventional treatment. However cystic lesions, usually of the medial aspect of the talus, do represent a therapeutic challenge.

Objectives: Description of early results using a new modality in musculoskeletal oncology.

Introduction: Radiofrequency as a malignant tumor ablative modality has been employed during the last decade in liver tumors. Extra-hepatic application in malignancies is new and its indications are not precisely defined. It has been used for more than ten years for osteoid osteoma ablation. Radiofrequency allows destruction of a precise sphere around the application tip. Ablation efficiency is monitored by the change in tissue conductance following tissue necrosis.

Methods: 10 patients scheduled to undergo limb sparing surgery were included. During the pre-operative angiography and embolization, tumors were treated by radio-frequency ablation. The precise location of the needle electrode was defined by real-time ultrasonography. The relation of the needle tip to large blood vessels was monitored by comparison of ultrasonography to angiography. Thus, precise ablation of the tumor tissue was possible without risk to the neurovascular bundle.

Results: Tumor necrosis was uniform in the center of the ablative sphere and declined to 60 percent in the periphery. No complications were encountered.

Discussion: This method appears to allow further shrinkage of the tumors prior to limb sparing surgery. This technique is rapid and does not require delay of surgery, as does isolated limb perfusion or neo-adjuvant chemotherapy. The procedure can be performed in sedated patients, thus obviating the need for general anesthesia prior to limb sparing surgery. It can be employed in areas were isolated limb perfusion is not anatomically feasible such as the pelvis. Further studies are required in order to better define the role of this technique as compared to intra-arterial chemotherapy or isolated limb perfusion.

Study design: In order to evaluate a new CECT (Continuous Enhanced Circulation Therapy) based on protocol for DVT prevention a prospective, randomize, single-blind study was designed to compare the effect of the new protocol to the current standard of care in DCT prophylaxis (LMWH).

Objectives: To evaluate and compare the incidence and severity of DVT between the two groups.

Background: Total hip and knee replacements are operations particularly prone to thromboembolic complications. Recommendations regarding prophylaxis have changed over the years. A treatment protocol was proposed, based upon the CECT system as the primary DVT prophylaxis method with the addition of low dose aspirin. This protocol is using two very safe treatment modalities with very low risk for adverse effects. The CECT system applies continuous mechanical enhancement of venous blood flow through a miniature, mobile, battery operated system.

Methods: 39 patients, who underwent total hip or knee replacement, were prospectively randomized into two groups. In the study group the patients received CECT system starting immediately after the induction of anesthesia and covering the operation and the first 5 postoperative days, within 12 hours after surgery aspirin 100 mg per day was added. In the control group the patients received Enoxaparin 40 mg per day for 5 postoperative days. A venography was performed at the 5th to 8th post-operative day and the DVT prevalence was compared.

Results: In the study group 3 patients out of 21 (14.3%) were found to have DVT (1 of them proximal), compared to 8 patients out of 18 (44.4%) in the control group (5 of them proximal). The differences between the two groups are statistically significant for both total and proximal DVT rates (p=0.037).

In the study group only 1 patient needed prolonged high dose anticoagulant treatment while 6 patients in the enoxaparin group were treated (p=0.020).

The cumulative incidence of adverse events in the study group was significantly lower than that observed in the control group (p=0.000). Average postoperative hospital stay was 8.4 days in the study group and 11.7 days in the control group (p=0.002).

The CECT device was very well tolerated by the patients and facilitated early mobilization.

Conclusions: The protocol combining CECT and Aspirin was found to be both safe the effective. Comparison to the standard prophylaxis with enoxaparin revealed significant advantage of the proposed protocol with: better DVT prevention, less adverse events and shorter hospital stay. Further research is needed in order to establish the place of this prophylaxis protocol as the treatment of choice in orthopaedic patients.

Objectives: Assessment of the need for bolt removal in long stem distally interlocked revision stems.

Introduction: Proximal stress shielding might prove in the long run detrimental to the success of distally fixed revision stems. In our department during the last 4 years a proximally fixed stem combined with distal interlocking has been used. The manufacturer recommends bolt removal 18 months after surgery. The current investigation was conducted in order to assess the need for bolt removal.

Methods: 22 consecutive stems inserted from 1997 to the present were included. In all these cases femoral bone loss was graded according to Paprosky. A locked long stem is indicated in bony deficiencies of Grade 2B, 2C or 3 (i.e. loss of at least the metaphysis shell with or without major diaphyseal bone loss). Volkmann’s trans-femoral approach was used in 19 cases and sliding trochanteric osteotomy in the rest. Impaction grafting or structural allografts were not used to stabilize the prosthesis. In all cases grade II fixation (according to D’Antonio) was achieved at the end of the procedure.

Results: Median follow-up is 14 months. There were no septic complications. In two cases bolts slippage allowed prosthesis subsidence. One stem had to be revised due to aseptic failure. During surgery the prosthesis was markedly smaller than the regenerated medullary canal, and proximal bony fixation was not achieved. One patient’s bolts broke and in another case screw migration into soft tissue occurred. All patients attained ambulatory status. In none of the patients were the screws removed.

Discussion: Our results seem not to support the manufacturer’s recommendation for elective screw removal. Osteotomy healing appears to occur in all cases, however, time to healing varies greatly. The range of complete healing is from 3 months to 24 months. It does not appear that bolt retention leads to an interference with bone healing and bone regeneration of the proximal femur at the osteotomy site. Bolt breakage is rare and does not appear to adversely affect the results at least in the short term.

Objectives: Development a giant cell tumor model arising from the mutated mesenchymal cells present in its stroma. This establishes the pathogenic mechanism of giant cell tumor, and allows the evaluation of the possible role of biphosphonates and retinoic acid in medical therapy of giant cell tumor of bone.

Introduction: In previous studies our group has shown that mesenchymal stroma contains mesenchymal cells capable of recruiting osteoclasts, and lacking capacity to undergo osteoblastic differentiation. These cells represent the actual neoplastic component of the tumor. In the current study, an attempt was made to establish a giant cell tumor in an animal model by injection of these cells.

Methods: 6 Balb/C named mice were used. The mice were kept in a laminar flow hood and injected when they were 4 weeks old. The injection was in an intra-osseous location into the distal femur. The cell inoculum consisted of 1 million stromal cells. The cells were derived from a grade III giant cell tumor occurring in the hip joint of a 30 years old woman. The mice were kept for 2 months and than sacrificed.

Results: A lytic lesion similar to that occurring in humans developed. The tumor consisted of stromal cells with interspersed osteoclasts. These were identified as being of host origin by mice-specific monoclonal antibodies. The tumor penetrated the cortex but did not infiltrate the articular cartilage. Metastases were not observed.

Discussion: Giant cell tumor of bone is typified by osteolytic bone destruction mediated by osteoclasts. In previous studies, our group has shown that the proliferation rate of the stromal component correlates closely with prognosis and grade of the tumor. The stromal component was shown to consist of pre-osteoblasts that fail to differentiate into osteoblasts, but instead recruit giant cells (osteoclasts), mediating bone destruction. Addition of retinoic acid in culture induces osteoblastogenesis cells by blocking AP-1. The current study confirms in an animal model that indeed the stromal cells are capable of osteoclast recruitment and bone destruction. This animal model might allow development of medical remedies to this tumor.

Study design: An experimental human study of retrieval material.

Objectives: Assessment and evaluation of the involvement of TNFα and Nitric oxide in sciatic pain.

Summary and background data: It appears that the inflammation produced by the herniated fragment is at least partially related to the sciatic pain. TNFα was found to be expressed by herniated nucleus polposus of rats and exogenous TNFα applied in vivo to rat nerve root produced neuropathologic changes and behavior deficit that mimicked experimental studies with herniated nucleus polposus (HNP) applied to nerve roots. Nitric oxide was shown to be involved in the mechanism that produce mechanical and thermal hyperalgesia in rats. Nitric oxide synthesis can be induced by different cytokines among them TNFα and is mediated by the enzyme Nitric oxide synthase. The current study was performed in order to evaluate the possible mechanism of action of TNFα in human herniated discs and define the relationship between nitric oxide and TNFα production by human discs.

Methods: Six herniated fragments of lumbar discs were compared to a similar number of normal intervertebral discs removed during spinal fusion procedures of the lumbar and thoracic spine for the presence of TNFα and the expression of Nitric oxide synthase.

Results: TNFα was expressed by chondrocytes of the herniated fragments but not by the same cells in normal discs. Similar expression pattern was noted for nitric oxide synthase. Both materials were not expressed in the healthy discs.

Conclusions: TNFα appears to be related to pain mechanism of disc herniation. It’s effect is mediated through Nitric oxide. It is well known that NSAIDs are relatively inefficient in modulating TNF-related pain. This might explain the lack of efficacy of currently used medications.

Vertebral fracture due to a metabolic bone disease or a neoplastic disease is a common and debilitating condition. It most often is associated with either osteoporosis or metastatic bone disease. Some of the patients suffering from such fractures continue to complain of back pain and deformity despite optimal medical therapy, including radiotherapy and biphosphonates.

Vertebroplasty, i.e. transcutaneous injection of bone cement into the vertebral body can serve as an internal fixation device and allows restoration of mechanical strength and partial restoration of the vertebral height.

During the year 2000, 17 vertebrae in 12 patients were injected. These were either lumbar or thoracic vertebrae. All patients reported decrease in pain and improved ambulation capacity.

Two minor complications were encountered including headache lasting for 72 hours prior to spontaneously resolving. This possibly indicates a transarachnoidal approach, the other complication has been cement leak below the posterior longitudinal ligament. The patient reported pain amelioration. No emergency surgical interventions were necessary to date.

Treatment of metastatic bone disease should be staged, with only a few vertebrae injected in each session, to prevent pulmonary embolization.

Vertebroplasty appears to allow excellent palliative treatment in patients suffering from unresectable primary tumors of the vertebrae, or more commonly, metastatic bone tumors as well as osteoporotic fractures.

Vertebroplasty has been developed during the last decade in France as a method to relieve pain in patients suffering from a metastatic disease of the spine, that are poor surgical candidates. The indications include: mechanical pain, compression fractures, lytic bone metastasis.

Contra-indications include neurological compromise, breaching of the posterior wall, complete pedicle destruction or a large anterior soft-tissue mass. Relative contra-indications include a single resectable metastasis and a radiation sensitive tumor.

The method has been refined during the last few years by the introduction of specialized delivery systems and tailor-made bone cements.

The state of the art of this emerging technique will be discusses as well as some exciting future developments such as cements that can actively destroy tumors by physical or chemical modifications.