Aims. Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques. Methods. Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S. 4. ). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads. Results. Experimental pull-out strengths were excellently correlated to the µFE pull-out stiffness of the ROI (R. 2. > 0.87) and FV (R. 2. > 0.84) models. No significant difference due to screw design was observed. Cement augmentation increased pull-out stiffness by up to 94% and 48% for L and R screws, respectively, but only increased bending stiffness by up to 6.9% and 1.5%, respectively. Cementing involving only one screw tip resulted in lower stiffness increases in all tested screw designs and loading cases. The stiffening effect of cement augmentation on pull-out and bending stiffness was strongly and negatively correlated to local bone density around the screw (correlation coefficient (R) = -0.95). Conclusion. This combined experimental, µCT and µFE study showed that regional analyses may be sufficient to predict fixation strength in pull-out and that full analyses could show that cement augmentation around pedicle screws increased fixation stiffness in both pull-out and bending, especially for low-density bone. Cite this article: Bone Joint Res 2021;10(12):797–806

Aims. Loosening of pedicle screws is a major complication of posterior spinal stabilisation, especially in the osteoporotic spine. Our aim was to evaluate the effect of cement augmentation compared with extended dorsal instrumentation on the stability of posterior spinal fixation. Materials and Methods. A total of 12 osteoporotic human cadaveric spines (T11-L3) were randomised by bone mineral density into two groups and instrumented with pedicle screws: group I (SHORT) separated T12 or L2 and group II (EXTENDED) specimen consisting of T11/12 to L2/3. Screws were augmented with cement unilaterally in each vertebra. Fatigue testing was performed using a cranial-caudal sinusoidal, cyclic (1.0 Hz) load with stepwise increasing peak force. Results. Augmentation showed no significant increase in the mean cycles to failure and fatigue force (SHORT p = 0.067; EXTENDED p = 0.239). Extending the instrumentation resulted in a significantly increased number of cycles to failure and a significantly higher fatigue force compared with the SHORT instrumentation (EXTENDED non-augmented + 76%, p < 0.001; EXTENDED augmented + 87%, p < 0.001). Conclusion. The stabilising effect of cement augmentation of pedicle screws might not be as beneficial as expected from biomechanical pull-out tests. Lengthening the dorsal instrumentation results in a much higher increase of stability during fatigue testing in the osteoporotic spine compared with cement augmentation. Cite this article: Bone Joint J 2016;98-B:1099–1105

Introduction. The main symptoms in multiple myeloma are the result of skeletal destruction mainly the vertebral column. The current treatments for multiple myeloma include radiotherapy and chemotherapy but unfortunately it is still incurable. However, the symptoms and quality of life of these patients can be improved by cement augmentation which has gained popularity in the recent years. Aim. To analyse the efficacy and safety of cement augmentation and to assess the survival and outcome of the patients with vertebral fractures secondary to multiple myeloma. Material and Methods. In this retrospective study, we reviewed the data over the last 3 years. Medical records review included correction of vertebral angle (VA), assessment of disability, survival and postoperative improvement in pain and functional status. Results. We reviewed 12 patients with 48 vertebral compression fractures including 9 male and 3 female patients. Mean age was 62.5 years (41–85). 5 patients had single vertebral involvement while 7 had multiple fractures at different levels in thoracolumbar spine. Average length of follow-up was 20.3 months (14–33 months). Based on Modified Tokuhashi score, the expected survival was less than 12 months in 2 patients and more than 12 months in the remaining patients. 11 patients are alive till date with average survival of 26 months (18–42 months) while 1 patient died, 23 months after the initial correction surgery. Prior to correction, the average vertebral angle (VA) was 10.60 (2.30 to 25.20) and after cement augmentation the average VA was 7.00 (1.60–22.80). Mean correction achieved was 3.60. There was no loss of vertebral height in any patient until their latest follow-up. Karnofsky performance score was more than 70 in 5 patients, 50–70 in 6 and less than 50 in 1 patient preoperatively while it improved to more than 70 in all patients postoperatively which indicates improvement in their functional status. All patients reported improvement in their pain level after surgery. No cement leakage or major complication occurred in these patients. Conclusion. Cement augmentation is a safe and effective way of treating the symptoms of multiple myeloma which occur due to vertebral metastases. It results in excellent pain control and improvement in quality of life

Hip fractures constitute the most debilitating complication of osteoporosis with a steadily increasing incidence in an aging population. Intramedullary nailing of osteoporotic proximal femoral fractures can be challenging because of poor implant anchorage in the femoral head. Recently, cement augmentation of PFNA blades with Polymethylmethycrylate (PMMA) has shown promising results by enhancing the cutout resistance in proximal femoral fractures. The aim of this biomechanical study was to assess the impact of cement augmentation on the fixation strength of TFNA blades and screws within the femoral head, and compare its effect with head elements placed in a center or antero–posterior off–center positions. Eight groups were formed out of 96 polyurethane foam specimens with low density, simulating isolated femoral heads with severe osteoporotic bone. The specimens in each group were implanted with either non–augmented or PMMA–augmented TFNA blades or screws in a center or antero–posterior off–center position, 7 mm anterior or 7 mm posterior. They were mechanically tested in a setup simulating an unstable pertrochanteric fracture with lack of postero–medial support and load sharing at the fracture gap. All specimens underwent progressively increasing cyclic loading until catastrophic construct failure. Varus–valgus and head rotation angles were monitored by an inclinometer mounted on the head. A varus collapse of 5° or a 10° head rotation were defined as the clinically relevant failure criterion. Load at failure for specimens with augmented TFNA head elements (screw center: 3799 N ± 326 (mean ± SD); blade center: 3228 N ± 478; screw off–center: 2680 N ± 182; blade off–center: 2591 N ± 244) was significantly higher compared to the respective non–augmented specimens (blade center: 1489 N ± 41; screw center: 1593 N ± 120; blade off–center: 1018 N ± 48; screw off–center: 515 N ± 73), p<0.001. In both non–augmented and augmented specimens, the failure load in center position was significantly higher compared to the respective off–center position, regardless of head element, p<0.001. Non–augmented TFNA blades in off–center position revealed significantly higher load at failure versus non–augmented screws in off–center position, p<0.001. Cement augmentation clearly enhances fixation stability of TFNA blades and screws. Non–augmented blades outperformed screws in antero–posterior off–center position. Positioning of TFNA blades in the femoral head is more forgiving than TFNA screws in terms of failure load. Augmentation with TFNA has not been approved by FDA

Aims. Fixation of osteoporotic proximal humerus fractures remains challenging even with state-of-the-art locking plates. Despite the demonstrated biomechanical benefit of screw tip augmentation with bone cement, the clinical findings have remained unclear, potentially as the optimal augmentation combinations are unknown. The aim of this study was to systematically evaluate the biomechanical benefits of the augmentation options in a humeral locking plate using finite element analysis (FEA). Methods. A total of 64 cement augmentation configurations were analyzed using six screws of a locking plate to virtually fix unstable three-part fractures in 24 low-density proximal humerus models under three physiological loading cases (4,608 simulations). The biomechanical benefit of augmentation was evaluated through an established FEA methodology using the average peri-screw bone strain as a validated predictor of cyclic cut-out failure. Results. The biomechanical benefit was already significant with a single cemented screw and increased with the number of augmented screws, but the configuration was highly influential. The best two-screw (mean 23%, SD 3% reduction) and the worst four-screw (mean 22%, SD 5%) combinations performed similarly. The largest benefits were achieved with augmenting screws purchasing into the calcar and having posteriorly located tips. Local bone mineral density was not directly related to the improvement. Conclusion. The number and configuration of cemented screws strongly determined how augmentation can alleviate the predicted risk of cut-out failure. Screws purchasing in the calcar and posterior humeral head regions may be prioritized. Although requiring clinical corroborations, these findings may explain the controversial results of previous clinical studies not controlling the choices of screw augmentation

We have developed a hollow perforated cannulated screw. One or more of these was implanted percutaneously in 11 patients with an osteolytic metastasis in the femoral neck and multiple metastases elsewhere. They were supplemented by one or two additional standard 6.5 mm cannulated screws in nine patients. Polymethylmethacrylate bone cement was injected through the screw into the neck of the femur using small syringes, as in vertebroplasty. The mean amount of cement injected was 23.2 ml (17 to 30). Radiotherapy was started on the fourth post-operative day and chemotherapy, on average, was resumed a day later.

Good structural stability and satisfactory relief from pain were achieved in all the patients. This technique may be useful in the palliation of metastases in the femoral neck.

Introduction

Pedicle screw pullout or loosening is increased in the osteoporotic spine. Recent studies showed a significant increase of pullout forces especially for PMMA-augmentation. With application of conventional viscosity PMMA the risk of cement extravasation is associated. This risk can be reduced by using radiofrequency-responsive, ultrahigh viscosity bone cement.

Posterior internal fixation systems undergo internal constraints resulting in high load bearing requirement for the pedicular screw/bone interface. Only few studies deal with the impact of the vertebral augmentation on the migration of pedicular screws. In this study, the impact of the pedicular screw augmentation has been investigated under physiological load for osteoporotic vertebras. The data have been proceeded to reduce the influence of vertebral geometry, which generally leads to results devoid of statistical meaning

In 8 osteoporotic vertebrae, two screws have been inserted in each vertebra: a non-augmented on one side and an augmented one on the contralateral side.

Compression tests have been performed (two consecutive 50 cycles load steps -100N and 200N-) to observe the displacement of the screw’s head. Two different setups have been employed: a free connection (FC) and a blocked connection (BC). A load step is successful if the migration between two consecutive cycles tends to zero. To reduce the impact of the vertebras’ geometry, the screws’ migration have been compared contra-laterally using the migration ratio (MR). MR of vertebrae is defined as the division of the augmented screw’s migration with the non-augmented screw’s migration.

All the augmented screws survived both test setups whereas the non-augmented failed the 200N FC load step. Significant differences are observable only for the highest successful load steps for each test setup: T-tests (P=0.039 and P=0.007 respectively) put into evidence that the results are statistically smaller than one. It is observable as well, that the BC induced fewer loads into the vertebrae: even non-augmented screw can withstand 200N load step.

As expected, augmentation of pedicular perforated screws increases their stability in osteoporotic vertebras undergoing large physiological load. This could be explained by the fact that the presence of PMMA increases the load transfer interface improving screw/PMMA complex bearing capacity. Smaller loads induce only small differences that are not significant.

INTRODUCTION

Over 85% of patients with multiple myeloma (MM) have bone disease, mostly affecting thoraco-lumbar vertebrae. Vertebral fractures can lead to pain and large spinal deformities requiring application of vertebroplasty (PVP). PVP could be enhanced by use of Coblation technique to remove lesions from compromised MM vertebrae prior to cement injection (C-PVP).

The purpose of this study was to determine the effect of cement mixing time on fixation augmentation in both healthy and simulated osteoporotic canine bone. In a canine diaphyseal model, screw insertion into liquid cement achieves greater bending stiffness and resists a greater load to failure than cement inserted as a paste. Bone cement in its liquid state may provide increased structural support in the setting of an osteoporotic fracture, possibly due to increased interdigitation of the cement with the screw threads and bone.

An inconsistency exists among orthopaedic surgeons with regards to the appropriate mixing time for bone cement to achieve optimal results. The purpose of this study was to determine the effect of cement mixing time on fixation augmentation in both healthy and simulated osteoporotic canine bone.

In a canine diaphyseal fracture model, screw insertion into liquid cement achieves greater bending stiffness and resists a greater load to failure than insertion into cement with the consistency of a paste.

Bone cement in its liquid state may provide increased structural support in the setting of an osteoporotic fracture, possibly due to increased interdigitation of the cement with the screw threads and bone.

Baseline stiffness for fourteen pairs of cadaveric canine femora was determined. A transverse diaphyseal osteotomy was created and fixed using an eight-hole DC plate and 3.5 mm screws. A 1cm gap was created at the osteotomy site simulating loss of bone. In the left femora, cement was mixed for one minute (liquid) prior to injection into pre-drilled holes; in the right femora, cement was mixed for five minutes prior to injection (thick paste). In each mixing time group, seven specimens were treated with a plate and properly sized pre-drilled and tapped holes (2.5mm), and seven received over-drilled holes (3.2 mm) to simulate osteoporotic bone. Four-point bending stiffness was determined for each plated construct, and normalized to baseline stiffness. Specimens were then loaded to failure.

Within the properly sized holes, there were no statistically significant differences (SSD) in bending stiffness with or without a gap. The liquid cement had a force to failure 77% greater than that of cement as a paste (p< 0.05). Within the over-sized holes, there was no SSD between liquid and paste without a gap. With a gap, liquid cement demonstrated an increased bending stiffness of 24 % (p< 0.05) and force to failure was 92% higher (p< 0.05).

Introduction and Aims: Bone cement (Polymethylmethacrylate) is commonly used to augment internal fixation in osteoporotic bone. An inconsistency exists among surgeons regarding the appropriate mixing time for bone cement to achieve optimal screw purchase. The study addresses the effect of cement viscosity on fixation augmentation in both healthy and simulated osteoporotic canine bone.

Method: Fourteen canine femora were plated using eight-hole DC plates and 3.5mm screws, repairing transverse diaphyseal osteotomies with and without a gap. In the left femora, cement was mixed for one minute (liquid) prior to injection into drilled and tapped holes that were either properly sized (2.5mm) or over-drilled (3.2mm) to simulate osteoporotic bone. In the right femora, cement was mixed for five minutes prior to injection (thick paste). Four-point bending stiffness for each plated construct was normalised to baseline stiffness, followed by failure loading.

Results: Within the properly sized holes, there were no significant differences in bending stiffness with or without a gap at the fracture site. The liquid cement had a force to failure 77% greater than that of cement as a paste (p< 0.05).

Within the over-sized holes simulating osteoporotic bone, there was no difference between liquid and paste without a gap. With a gap, liquid cement demonstrated an increased bending stiffness of 24% (p< 0.05) and force to failure was 92% higher (p< 0.05).

Bone cement in its liquid state may provide increased structural support in the setting of an osteoporotic fracture, possibly due to increased interdigitation of the cement with the screw threads and bone.

Conclusion: In a canine diaphyseal fracture model, screw insertion into liquid cement achieves greater bending stiffness and resists a greater load to failure than insertion into cement with the consistency of a paste.

The augmentation of fixation with bone cement is increasingly being used in the treatment of severe osteoporotic fractures. We investigated the influence of bone quality on the mechanics of augmentation of plate fixation in a distal femoral fracture model (AO 33 A3 type). Eight osteoporotic and eight non-osteoporotic femoral models were randomly assigned to either an augmented or a non-augmented group. Fixation was performed using a locking compression plate. In the augmented group additionally 1 ml of bone cement was injected into the screw hole before insertion of the screw. Biomechanical testing was performed in axial sinusoidal loading. Augmentation significantly reduced the cut-out distance in the osteoporotic models by about 67% (non-augmented mean 0.30 mm (sd 0.08) vs augmented 0.13 mm (sd 0.06); p = 0.017). There was no statistical reduction in this distance following augmentation in the non-osteoporotic models (non-augmented mean 0.15 mm (sd 0.02) vs augmented 0.15 mm (sd 0.07); p = 0.915). In the osteoporotic models, augmentation significantly increased stability (p = 0.017).

Cite this article: Bone Joint J 2013;95-B:1406–9.

Aims. Proximal humeral fractures are the third most common fracture among the elderly. Complications associated with fixation include screw perforation, varus collapse, and avascular necrosis of the humeral head. To address these challenges, various augmentation techniques to increase medial column support have been developed. There are currently no recent studies that definitively establish the superiority of augmented fixation over non-augmented implants in the surgical treatment of proximal humeral fractures. The aim of this systematic review and meta-analysis was to compare the outcomes of patients who underwent locking-plate fixation with cement augmentation or bone-graft augmentation versus those who underwent locking-plate fixation without augmentation for proximal humeral fractures. Methods. The search was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Articles involving patients with complex proximal humeral fractures treated using open reduction with locking-plate fixation, with or without augmentation, were considered. A meta-analysis of comparative studies comparing locking-plate fixation with cement augmentation or with bone-graft augmentation versus locking-plate fixation without augmentation was performed. Results. A total of 19 studies were included in the qualitative synthesis, and six comparative studies were included in the meta-analysis. Overall, 120 patients received locking-plate fixation with bone-graft augmentation, 179 patients received locking-plate fixation with cement augmentation, and 336 patients received locking-plate fixation without augmentation. No statistically relevant differences between the augmented and non-augmented cohorts were found in terms of the Disabilities of the Arm, Shoulder and Hand questionnaire score and Constant-Murley Score. The cement-augmented group had a significantly lower rate of complications compared to the non-augmented group. Conclusion. While locking-plate fixation with cement augmentation appears to produce a lower complication rate compared to locking-plate fixation alone, functional outcomes seem comparable between augmented and non-augmented techniques. Cite this article: Bone Joint J 2024;106-B(7):646–655

Aims. The purpose of the study was to investigate whether closed intramedullary (IM) nailing with percutaneous cement augmentation is better than conventional closed nailing at relieving pain and suppressing tumours in patients with metastases of the femur and humerus. Patients and Methods. A total of 43 patients (27 men, 16 women, mean age 63.7 years, standard deviation (. sd. ) 12.2; 21 to 84) underwent closed IM nailing with cement augmentation for long bone metastases. A further 27 patients, who underwent conventional closed IM nailing, served as controls. Pain was assessed using a visual analogue scale (VAS) score pre-operatively (pre-operative VAS), one week post-operatively (immediate post-operative VAS), and at six weeks post-operatively (follow-up post-operative VAS). Progression of the tumour was evaluated in subgroups of patients using F-18-fludeoxyglucose (F-18-FDG) positron emission tomography (PET)/computed tomography (CT) and/or bone scintigraphy (BS), at a mean of 8.8 and 7.2 months post-operatively, respectively. Results. The mean pain scores of patients who underwent closed nailing with cement augmentation were significantly lower than those of the control patients post-operatively (immediate post-operative VAS: 3.8, . sd. 0.9 versus 6.0, . sd. 0.9; follow-up post-operative VAS: 3.3, . sd. 2.5 versus 6.6, . sd. 2.2; all p < 0.001). The progression of the metastasis was suppressed in 50% (10/20) of patients who underwent closed nailing with augmentation, but in only 8% (1/13) of those in the control group. Conclusion. Percutaneous cement augmentation of closed IM nailing improves the relief of pain and limits the progression of the tumour in patients with metastases to the long bones. Take home message: Percutaneous cement augmentation while performing closed IM nailing has some advantages for long bone metastases. Cite this article: Bone Joint J 2016;98-B:703–9

Introduction and Objective. Trochanteric fractures are associated with increasing incidence and represent serious adverse effect of osteoporosis. Their cephalomedullary nailing in poor bone stock can be challenging and associated with insufficient implant fixation in the femoral head. Despite ongoing implant improvements, the rate of mechanical complications in the treatment of unstable trochanteric fractures is high. Recently, two novel concepts for nailing with use of a helical blade – with or without bone cement augmentation – or an interlocking screw have demonstrated advantages as compared with single screw systems regarding rotational stability and cut-out resistance. However, these two concepts have not been subjected to direct biomechanical comparison so far. The aims of this study were to investigate in a human cadaveric model with low bone density (1) the biomechanical competence of cephalomedullary nailing with use of a helical blade versus an interlocking screw, and (2) the effect of cement augmentation on the fixation strength of the helical blade. Materials and Methods. Twelve osteoporotic and osteopenic femoral pairs were assigned for pairwise implantation using either short TFN-ADVANCED Proximal Femoral Nailing System (TFNA) with a helical blade head element, offering the option for cement augmentation, or short TRIGEN INTERTAN Intertrochanteric Antegrade Nail (InterTAN) with an interlocking screw. Six osteoporotic femora, implanted with TFNA, were augmented with 3 ml cement. Four study groups were created – group 1 (TFNA) paired with group 2 (InterTAN), and group 3 (TFNA augmented) paired with group 4 (InterTAN). An unstable pertrochanteric OTA/AO 31-A2.2 fracture was simulated. All specimens were biomechanically tested until failure under progressively increasing cyclic loading featuring physiologic loading trajectory, with monitoring via motion tracking. Results. T-score in groups 3 and 4 was significantly lower compared with groups 1 and 2, p=0.03. Stiffness (N/mm) in groups 1 to 4 was 335.7+/−65.3, 326.9+/−62.2, 371.5+/−63.8 and 301.6+/−85.9, being significantly different between groups 3 and 4, p=0.03. Varus (°) and femoral head rotation around neck axis (°) after 10,000 cycles were 1.9+/−0.9 and 0.3+/−0.2 in group 1, 2.2+/−0.7 and 0.7+/−0.4 in group 2, 1.5+/−1.3 and 0.3+/−0.2 in group 3, and 3.5+/−2.8 and 0.9+/−0.6 in group 4, both with significant difference between groups 3 and 4, p<=0.04. Cycles to failure and failure load (N) at 5° varus in groups 1 to 4 were 21428+/−6020 and 1571.4+/−301.0, 20611+/−7453 and 1530.6+/−372.7,21739+/−4248 and 1587.0+/−212.4, and 18622+/−6733 and 1431.1+/−336.7, both significantly different between groups 3 and 4, p=0.04. Conclusions. From a biomechanical perspective, cephalomedullary nailing of trochanteric fractures with use of helical blades is comparable to interlocking screw fixation in femoral head fragments with low bone density. Moreover, bone cement augmentation of helical blades considerably improves their fixation strength in poor bone quality

Introduction. Spine is a common site for haematological malignancies. Multiple myeloma affects the spine in 70% of cases. New guidelines were published in 2015 to help manage spinal haematological malignancies. Despite neural compression or spinal instability, instrumentation of the spine should be avoided. Surgery carries significant risks of wound complications and more importantly delaying the definitive chemotherapy and radiotherapy. Cement augmentation and bracing for pain and prevention of deformity is key to the new strategies. We aimed to evaluate the different treatment modalities adopted in the spine unit at St George's hospital for spinal haematological malignancies. We compared our practice to the current guidelines published in 2015. Methods. Retrospective review of all spinal haematological malignancy patients who were discussed in the spinal MDT and managed through the spine unit at St George's hospital in the period between April 2019 and February 2021. We analysed the demographics of the patients treated in this period and compared the management modalities adopted in the unit to the current British haematological guidelines. Results. 139 patients were included in this study, 61.9% of them were male. 70 cases came through the MSCC pathway. 15 patients had their spinal involvement in the lumbar spine only below the conus. The Bilsky Grades of the other 124 cases were B0: 35.97 % 1a: 4.31%%, 1b: 7.19%, 1c: 3.59%, 2: 5.75% 3: 32.37%. 43 patients (30.9 %) had neurological deficits on presentation. 70 cases were treated conservatively (50.35%), 21 were treated with brace only (15.1%), 25 had BKP (17.98%) and 23 were treated with instrumentation (16.54%). The number of instrumented cases was small and trending down and cement augmentation and bracing were more frequently chosen for these patients. This comes in accordance to the British haematological guidelines. Conclusion. Utilising BJH 2015 guidelines we have reduced our instrumented operative case load. There is a higher percentage of BKP and Bracing in accordance to the algorithm

Femoroplasty is the process of injecting cement (cement augmentation) into the proximal femur to prevent osteoporotic hip fractures. Femoroplasty increases the strength and energy to failure of the femur and can be performed in a minimally-invasively manner with lower hospitalization costs and reduced recovery. Our hypothesis was that efficient cement augmentation strategies can be identified via computational optimization. Therefore, using patient-specific planning we can minimize cement volume while increasing bone strength and reducing the risk of fracture. We proposed an in-silico methodology that was validated with in vitro experiments. A discrete particle model for cement infiltration was used to determine the optimum volume and filling pattern of the cement such that the best outcome was achieved. Several artificial bones were scanned before and after cement augmentation to applied previous in silico methodology. Then those femurs were mechanically tested (non-augmented and augmented). Therefore, in silico methodology was validated. Cement augmentation significantly increased the yield load. Predicted yield loads correlated well with the experiments. Results suggest that patient-specific planning of femoroplasty reduces the risk of hip fracture while minimizing the amount of cement required

Introduction. In complex primary and revision total knee replacement (TKR) the operating surgeon may encounter proximal tibial bone defects. The correct management of such defects is fundamental to both the initial stability and long-term survival of the prosthesis. Cement or metal augments have been used to address some such type II unconstrained defects [1]. Aim. The aim of this finite element (FE) study was to analyse the comparative behaviour of cement and metal based augments and quantify the stresses within these different augments and underlying cancellous bone. Materials and methods. A three-dimensional FE model was constructed from a computer tomography (CT) scan of the proximal tibia using SIMPLEWARE v3.2 image processing software. The tibial component of a TKR was implanted with either a block or wedge-shaped augment made of either metal or cement. The model was axially loaded with a force of 3600N and testing was conducted with both evenly and eccentrically distributed loads. Results. Upon loading the FE model, the von-Mises stresses in the cancellous bone underneath the augments were found to be higher with cement based augments in comparison their metal based counterparts. This was evident with both block and wedge-shaped augments. The FE model demonstrated that compressive stresses within the metal based augments were greater than those within the cement based augments. This was evident with both block and wedge designs. Upon even loading the maximum recorded compressive stresses within the metal augments were 5 times less than the endurance limit of the material [3]. However, the maximum recorded compressive stresses within cement augments were only half the endurance limit of the material [4] and upon eccentric loading compressive stresses in excess of the endurance limit were recorded. Discussion. The FE model has demonstrated that cement based augments undergo a greater deformation when loaded and therefore transfer greater loads to the underlying cancellous bone. This is a result of the inherent flexibility of the cement based augment in comparison to the stiffer metal counterparts. The greater transference of load to cancellous bone with cement based augments may reduce the possibility of stress shielding. However, the compressive stresses within cement based augments are too close to the endurance limit of the material and with uneven loading even exceed it. This would imply that cement based augments are more prone to fatigue failure than their metal counterparts. Conclusion. This FE study supports the use of metal based augments over cement based augments in augmented and revision TKR surgery

Intramedullary nails (IMNs) are the current gold standard for treatment of long bone diaphyseal and selected metaphyseal fractures. Their design has undergone many revisions to improve fixation techniques, conform to the bone shape with appropriate anatomic fit, reduce operative time and radiation exposure, and extend the indication of the same implant for treatment of different fracture types with minimal soft tissue irritation. The IMNs are made or either titanium alloy or stainless steel and work as load-sharing internal splints along the long bone, usually accommodating locking elements – screws and blades, often featuring angular stability and offering different configurations for multiplanar fixation – to secure secondary fracture healing with callus formation in a relative-stability environment. Bone cement augmentation of the locking elements can modulate the construct stiffness, increase the surface area at the bone-implant interface, and prevent cut-through of the locking elements. The functional requirements of IMNs are related to maintaining fracture reduction in terms of length, alignment and rotation to enhance fracture healing. The load distribution during patient's activities is along the entire bone-nail interface, with nail length and anatomic fit being important factors to avoid stress risers

Intramedullary nailed high proximal tibial fractures rely on the proximal screw-bone interface to provide stability, which can be insufficient in low-density bones. This study investigated the biomechanics of proximal screw cement augmentation in intramedullary nailing of high proximal tibial fractures. Mechanical stability in flexion/extension, varus/valgus and torsion was tested on six pairs of cadaveric proximal tibiae, with/without cement augmentation. Cement augmentation significantly increased construct stability in torsion and demonstrated a trend towards improved varus/valgus stabilization. Surprisingly, cement augmentation significantly decreased stability in flexion/extension, suggesting the potential benefits of cement augmentation may be limited in intramedullary nailed high proximal tibial fractures. This study assessed the biomechanical effects of augmenting proximal screws with cement in intramedullary nailing of high proximal third tibial fractures. While increased biomechanical stability was seen in torsion and varus/valgus, the reduction in stability in flexion/extension suggests that there may be limited benefit in cement augmentation in the nailing of high proximal tibia fractures. High proximal tibial fractures fixed with intramedullary nailing rely primarily on proximal screw fixation to provide stability. Cement augmentation of the proximal screws may provide needed increased construct stability in low-density tibiae. Cement augmentation provided a significant increase in construct stability in torsion (37.5% ± 8.0%, p< 0.05), with a trend toward increased stability in varus/valgus (25.5% ± 36.2%, p=0.08). Conversely, stability in flex-ion/extension was significantly decreased with the use of cement (25.9% ± 13.0%, p< 0.05). Reamed intramedullary nails (Zimmer, MDN) were implanted into six pairs of elderly cadaveric fresh-frozen proximal tibiae and secured using four proximal screws (two transverse, two oblique, 4.5mm diameter). Bone cement was injected into the screw holes just prior to screw insertion to augment the bone-screw interface in one tibia from each pair. Specimen stability was tested in flexion/extension and varus/valgus loading to 12Nm and in torsion to 7Nm. Displacement data was generated and analyzed using a repeated measures design. We hypothesized that intramedullary nail-bone construct stability would be increased with cement augmentation, particularly in low-density specimens. While construct stability was improved in torsion and varus/valgus, surprisingly stability consistently decreased in flexion/extension

Objectives. Cement augmentation of pedicle screws could be used to improve screw stability, especially in osteoporotic vertebrae. However, little is known concerning the influence of different screw types and amount of cement applied. Therefore, the aim of this biomechanical in vitro study was to evaluate the effect of cement augmentation on the screw pull-out force in osteoporotic vertebrae, comparing different pedicle screws (solid and fenestrated) and cement volumes (0 mL, 1 mL or 3 mL). Materials and Methods. A total of 54 osteoporotic human cadaver thoracic and lumbar vertebrae were instrumented with pedicle screws (uncemented, solid cemented or fenestrated cemented) and augmented with high-viscosity PMMA cement (0 mL, 1 mL or 3 mL). The insertion torque and bone mineral density were determined. Radiographs and CT scans were undertaken to evaluate cement distribution and cement leakage. Pull-out testing was performed with a material testing machine to measure failure load and stiffness. The paired t-test was used to compare the two screws within each vertebra. Results. Mean failure load was significantly greater for fenestrated cemented screws (+622 N; p ⩽ 0.001) and solid cemented screws (+460 N; p ⩽ 0.001) than for uncemented screws. There was no significant difference between the solid and fenestrated cemented screws (p = 0.5). In the lower thoracic vertebrae, 1 mL cement was enough to significantly increase failure load, while 3 mL led to further significant improvement in the upper thoracic, lower thoracic and lumbar regions. Conclusion. Conventional, solid pedicle screws augmented with high-viscosity cement provided comparable screw stability in pull-out testing to that of sophisticated and more expensive fenestrated screws. In terms of cement volume, we recommend the use of at least 1 mL in the thoracic and 3 mL in the lumbar spine. Cite this article: C. I. Leichtle, A. Lorenz, S. Rothstock, J. Happel, F. Walter, T. Shiozawa, U. G. Leichtle. Pull-out strength of cemented solid versus fenestrated pedicle screws in osteoporotic vertebrae. Bone Joint Res 2016;5:419–426

Aim. The aim of this FE study was to analyse the comparative behaviour of cement and metal based augments in TKR and quantify the stresses within these different augments and underlying cancellous bone. Materials and methods. A three-dimensional FE model was constructed from a CT scan of the proximal tibia using SIMPLEWARE v3.2 image processing software. The tibial component of a TKR was implanted with either a block or wedge-shaped augment made of either metal or cement. The model was axially loaded with a force of 3600N and testing was conducted with both evenly and eccentrically distributed loads. Results. Upon loading the FE model, the von-Mises stresses in the cancellous bone underneath the augments was higher with cement based augments in comparison their metal counterparts. When evenly loaded the maximum recorded compressive stresses within the metal augments were 5 times less than the endurance limit of the material, whilst the stresses within cement augments were only half the endurance limit of the material. Upon eccentric loading compressive stresses within the cement based augments in excess of the endurance limit were recorded. Discussion. The FE model has demonstrated that cement based augments undergo greater deformation when loaded and transfer greater loads to the underlying cancellous bone thus reducing the possibility of stress shielding. However, the compressive stresses within cement based augments are too close to the endurance limit of the material and with uneven loading even exceed it. This would imply that cement based augments are more prone to fatigue failure than their metal counterparts. Conclusion. This study supports the use of metal over cement based augments in augmented and revision TKR surgery

Purpose: The objectives of this study were to determine the effect of posterior instrumentation extension and/or cement augmentation on immediate stabilization of the instrumented level and biomechanical changes adjacent to the spinal instrumentation. Methods: This study was designed for repeated measures comparison, using 12 T9-L3 human cadaveric segments, to test the effects of posterior rod extension and cement augmentation following T11 corpectomy. The spine was stabilized with a vertebral body replacement device and with posterior instrumentation from T10 to T12. The T12 pedicle tracts were over-drilled to simulate loosened screws in an osteoporotic spine. The T10 screws were not over-drilled but cemented so as to keep the superior segments constant. Flexibility tests were first carried out on the intact specimen, followed by 3 randomized surgical conditions without cement and lastly the 3 conditions after cement augmentation. The 3 conditions were: 1) no posterior extension rods to L1, 2) flexible extension rods, and 3) rigid extension rods. A combined testing/analysis protocol that used both the traditional flexibility method and a hybrid technique [Panjabi 2005] was adopted. Flexibility tests with +/−5 Nm pure moments in flexion-extension, axial rotation and lateral bending were carried out and vertebral bodies’ motion in 3-D were collected. Two-way repeated measures ANOVA analyses were carried out on ROM between cement augmentation (factor 1) and the posterior rod extension (factor 2) on each flexibility test direction. An alpha of 0.05 was chosen. Newman-Keuls post-hoc analyses were carried out to compare between surgical techniques. Results: Using the flexibility protocol, a reduction in ROMs at the destabilized level was observed with cement augmentation of screws or extension with rigid or flexible posterior rods to adjacent distal level. With the hybrid protocol, ROMs at adjacent level (T12-L1) were reduced with rod extension, but not with cement. Conclusions: The results of this study suggest that cement augmentation would enhance stabilization, but create possible adjacent level effects due to increased motion and strain, while additional flexible extension rods would reduce biomechanical changes at the level of extension. Funding: 2 Funding Parties: CIHR

Interbody fusion aims to treat painful disc disease by demobilising the spinal segment through the use of an interbody fusion device (IFD). Diminished contact area at the endplate interface raises the risk of device subsidence, particularly in osteoporosis patients. The aim of the study was to ascertain whether vertebral body (VB) cement augmentation would reduce IFD subsidence following dynamic loading. Twenty-four human two-vertebra motion segments (T6–T11) were implanted with an IFD and distributed into three groups; a control with no cement augmentation; a second with PMMA augmentation; and a third group with calcium phosphate (CP) cement augmentation. Dynamic cyclic compression was applied at 1Hz for 24 hours in a specimen specific manner. Subsidence magnitude was calculated from pre and post-test micro-CT scans. The inferior VB analysis showed significantly increased subsidence in the control group (5.0±3.7mm) over both PMMA (1.6±1.5mm, p=.034) and CP (1.0±1.1mm, p=.010) cohorts. Subsidence in the superior VB to the index level showed no significant differences (control 1.6±3.0mm, PMMA 2.1±1.5mm, CP 2.2±1.2mm, p=.811). In the control group, the majority of subsidence occurred in the lower VB with the upper VB displaying little or no subsidence, which reflects the weaker nature of the superior endplate. Subsidence was significantly reduced in the lower VB when both levels were reinforced regardless of cement type. Both PMMA and CP cement augmentation significantly affected IFD subsidence by increasing VB strength within the motion segment, indicating that this may be a useful method for widening indications for surgical interventions in osteoporotic patients

Aims. The aim of this study was to compare the peak pull-out force (PPF) of pedicle-lengthening screws (PLS) and traditional pedicle screws (TPS) using instant and cyclic fatigue testing. Materials and Methods. A total of 60 lumbar vertebrae were divided into six groups: PLS submitted to instant pull-out and fatigue-resistance testing (groups A1 and A2, respectively), TPS submitted to instant pull-out and fatigue-resistance testing (groups B1 and B2, respectively) and PLS augmented with 2 ml polymethylmethacrylate, submitted to instant pull-out and fatigue-resistance testing (groups C1 and C2, respectively). The PPF and normalized PPF (PPFn) for bone mineral density (BMD) were compared within and between all groups. Results. In all groups, BMD was significantly correlated with PPF (r = 0.83, p < 0.001). The PPFn in A1 was significantly less than in B1 (p = 0.006) and C1 (p = 0.002). The PPFn of A2 was significantly less than in B2 (p < 0.001) and C2 (p < 0.001). The PPFn in A1, B1, and C1 was significantly greater than in A2 (p = 0.002), B2 (p = 0.027), and C2 (p = 0.003). There were no significant differences in PPFn between B1 and C1, or between B2 and C2. Conclusion. Pedicle lengthening screws with cement augmentation can provide the same fixation stability as traditional pedicle screws and may be a viable clinical option. Cite this article: Bone Joint J 2018;100-B:516–21

Aims. Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically. Methods. Eight pairs of three-part humeral fractures were randomly assigned for pairwise instrumentation using either a prototype gliding plate or a standard PHILOS plate, and four pairs were fixed using the gliding plate with bone cement augmentation of its proximal screws. The specimens were cyclically tested under progressively increasing loading until perforation of a screw. Telescoping of a screw, varus tilting and screw migration were recorded using optical motion tracking. Results. Mean initial stiffness (N/mm) was 581.3 (. sd. 239.7) for the gliding plate, 631.5 (. sd. 160.0) for the PHILOS and 440.2 (. sd. 97.6) for the gliding augmented plate without significant differences between the groups (p = 0.11). Mean varus tilting (°) after 7500 cycles was comparable between the gliding plate (2.6; . sd. 1.9), PHILOS (1.2; . sd. 0.6) and gliding augmented plate (1.7; . sd. 0.9) (p = 0.10). Similarly, mean screw migration(mm) after 7500 cycles was similar between the gliding plate (3.02; . sd. 2.85), PHILOS (1.30; . sd. 0.44) and gliding augmented plate (2.83; . sd. 1.18) (p = 0.13). Mean number of cycles until failure with 5° varus tilting were 12702 (. sd. 3687) for the gliding plate, 13948 (. sd. 1295) for PHILOS and 13189 (. sd. 2647) for the gliding augmented plate without significant differences between the groups (p = 0.66). Conclusion. Biomechanically, plate fixation using a new gliding screw technology did not show considerable advantages in comparison with fixation using a standard PHILOS plate. Based on the finding of telescoping of screws, however, it may represent a valid approach for further investigations into how to avoid the cut-out of screws. Cite this article: Y. P. Acklin, I. Zderic, J. A. Inzana, S. Grechenig, R. Schwyn, R. G. Richards, B. Gueorguiev. Biomechanical evaluation of a new gliding screw concept for the fixation of proximal humeral fractures. Bone Joint Res 2018;7:422–429. DOI: 10.1302/2046-3758.76.BJR-2017-0356.R1

The February 2014 Oncology Roundup. 360 . looks at: suspicious lesions; limb salvage in pelvic sarcomas; does infection affect oncological survival?; cancer patient pathways; radiological arthritis with cement augmentation in GCT; and post-chemotherapy increase in tumour volume as a predictor of poor prognosis

To evaluate our results of treatment of kyphosis following osteoporotic fractures of the last 3 years. 28 women with a mean age of 63,2 years were treated for a painful kyphotic deformity of a mean Cobb angle 76,1°. They all had posterior fusion with pedicular screws and rods enhanced with autologous bone graft as well as allografts. Cement augmentation was used in a number of screws. A cell saver for auto transfusion and continuous neurophysiological monitoring was used intraoperatively in all cases. All patients fitted with a thoracolumbar brace for 3 months. The postoperative mean Cobb angle was 45,2° (40,6% improvement). Pain questionnaires at a mean postoperative follow up of 16 months showed excellent results in 10 patients (35,71%), good in 8 patients (28,57%), satisfactory in 6 patients (21,42%) and poor results in 4 patients (14,28%). All patients were satisfied with the cosmetic result. 2 patients presented a postoperative infection that was treated with debridement and antibiotics. Kyphotic deformity following osteoporotic fractures may treated satisfactory with rods and pedicular screws with cement augmentation

To investigate and compare the biomechanical characteristics of Bipedicular versus Unipedicular Vertebroplasty in cadaveric vertebra. Cadaveric single level vertebra were used to evaluate Bipedicular versus Unipedicular Vertebroplasty as an intervention for vertebral compression fractures. Cadaveric vertebra were assigned to two arms: Arm A simulated a wedge fracture followed by bipedicular cement augmentation; Arm B simulated a wedge fracture followed by unipedicular cement augmentation. Micro-CT imaging was performed to assess vertebral dimension, cement fill volumes and bone mineral density. All augmented specimens were then compressed under a static eccentric flexion load to failure. Pre and post augmentation failure load and stiffness were used to compare the two groups. Results suggest, when compared with actual failure strength, that the product of bone mineral density and endplate surface area gave a good prediction of failure strength for specimens in both arms. The mean cement volume fill of augmented vertebral bodies was 22.8% ± 7.21%. The bipedicular group showed a reduction in stiffness but an increase in post augmentation failure load of 1.09. The unipedicular group also showed a reduction in stiffness but showed a much greater increase in post augmentation failure load of 1.68. Preliminary data from this study suggests there is a significant reduction in stiffness following both bipedicular and unipedicular vertebroplasty. There is a significant increase in failure load post augmentation in the unipedicular group

The radiological and biomechanical assessment using cement augmented cannulated pedicle screw (Biomet. ®. , Omega 21. ®. ) and the correlation of the cement volume to the pullout strength needed for each screw. Cadaveric vertebrae of different lumbar levels were used. Through cannulated pedicle screw a definite volume of cement was applicated. The bone volume occupied by cement was assessed by means of segmentation after Computer Tomography. Biomechanical Pullout tests and statistical correlation analysis were then performed. The maximum pullout strength was 1361 N and the minimum pullout strength was 172 N (SD 331 N). The maximum cement volume was 5,29 cm3 and the minimum 1,02 cm3 (SD 1,159). The maximum cement diameter was 26,6 cm and the minimum cement diameter was 20,7 cm (SD 1,744). There is statistically significant correlation between the pullout strength and the injected cement volume (p< 0,05). The cannulated pedicle screw was used for a better fixation in the vertebral body. The cement augmentation with this technique is easier and seems to be safer than cement augmentation of non cannulated screws. Pullout strength of the cannulated screws correlates positively with the cement volume. It is though not influenced either by the total vertebral volume or by the ratio cement volume to vertebral volume or by the maximum diameter of the cement drough

In severe destructive spinal infections, with neurological deficit, progressive deformity or uncontrolled sepsis, the mainstay of treatment is surgical debridement with anterior and posterior stabilisation. We retrospectively reviewed 14 patients (11 Male 3 female) with a mean age of 63 (range 38 to 85) who underwent anterior only surgery consisting of an expandable vertebral body cage and a ventrolateral locking plate (Synthes). Organisms included Tuberculosis (7), Staphylococcus (5), E-Coli (1) and Pseudomonas (1). Radiological and functional outcomes were assessed upto 18 months post surgery. Cobb angles were used to measure angular deformity. Good early results in terms of safety, resolution of pain, control of deformity and improvement of neurological deficits was observed. Average blood loss was 633mls (range 300mls to 1500mls) with a mean deformity correction of 23 degrees. Post operative radiological assessment showed the cages to be relatively stable in the under 80 yrs groups (mean loss of correction 15 %). In elderly patients (> 80 yrs) there was significant subsidence leading to a loss of correction (mean 52%) which required stabilisation using vertebral body cement augmentation. In one case, there was implant displacement requiring revision and additional posterior stabilisation. 11 patients showed significant improvement in neurology and 3 patients remained neurologically normal ie Frankel E. We propose assessing severe spinal infections using the spinal trilogy of neurological deficit, deformity and sepsis. Anterior stabilisation using an expandable cage and locking plate alone or with additional vertebral body cement augmentation in elderly patients provides a satisfactory solution for severe destructive spinal infections. It preserves the posterior column and reduces the need for further posterior surgery

We studied the biomechanical behaviour of three sliding fixation devices for trochanteric femoral fractures. These were a titanium alloy sideplate and lag screw, a titanium alloy sideplate and dome plunger with cement augmentation, and a stainless-steel sideplate and lag screw. We used 18 mildly osteoporotic cadaver femora, randomly assigned to one of the three fixation groups. Four displacement and two strain gauges were fixed to each specimen, and each femur was first tested intact (control), then as a two-part fracture and then as a four-part intertrochanteric fracture. A range of physiological loads was applied to determine load-bearing, load-sharing and head displacement. The four-part-fracture specimens were subsequently tested to failure to determine maximum fixation strengths and modes of failure. The dome-plunger group failed at a load 50% higher than that of the stainless-steel lag-screw group (p < 0.05) and at a load 20% higher than that of the titanium-alloy lag-screw group (NS). All 12 lag-screw specimens failed by cut-out through the femoral head or neck, but none of the dome-plunger group showed movement within the femoral head when tested to failure. Strain-gauge analysis showed that the dome plunger produced considerably less strain in the inferior neck and calcar region than either of the lag screws. Inferior displacement of the femoral head was greatest for the dome-plunger group, and was due to sliding of the plunger. The dome plunger with cement augmentation was able to support higher loads and did not fail by cut-out through the femoral head.(ABSTRACT TRUNCATED AT 250 WORDS)

Numerous studies have examined the biomechanical properties of the vertebral body following PMMA cement augmentation for the treatment of osteoporotic vertebral body fractures. To date there is no published literature reporting the effects of Vertebroplasty on internal intervertebral disc biomechanics which in turn have been shown to reflect loading patterns of the vertebral column. To study effects of PMMA cement augmentation of vertebral body fractures on intervertebral disc biomechanics using stress prolifometry to assess differential anterior and posterior vertebral column loading. Eight cadaveric motion segments were individually loaded on a hydraulically powered materials testing machine under 1.5kN of axial compression. Following fracture induction the lower vertebral body underwent Vertebroplasty. Profiles of the vertically acting compressive stress were obtained by pulling a pressure sensitive transducer along the mid-sagittal diameter of the intervertebral disc. “Stress profile” measurements were obtained before fracture, following fracture, and after vertebro-plasty both in extension and flexion. Stress profiles were integrated over area to calculate the compressive force across the disc. The compressive load acting on the neural arch was calculated by subtracting the disc force from the applied 1.5kN load. In flexed postures posterior column loading increased from 17.1% to 42.2% following fracture (p< 0.01) and then decreased significantly from 42.2% to 23.68% following vertebroplasty (p< 0.03). There was no significant difference between pre-fracture and post-vertebroplasty status (p=0.11). In extended posture, fracture produced increased posterior column loading 72.9% vs 51.8% (p< 0.005) and following vertebroplasty there was no significant change (p=0.2). In moderate degrees of flexion, vertebroplasty produces normalisation of load bearing through the anterior vertebral column and hence offloads the posterior elements to a significant degree. This could be postulated, to partly account for the analgesic effect seen following vertebroplasty in the clinical setting

The August 2024 Shoulder & Elbow Roundup³⁶⁰ looks at: Comparing augmented and nonaugmented locking-plate fixation for proximal humeral fractures in the elderly; Elevated five-year mortality following shoulder arthroplasty for fracture; Total intravenous anaesthesia with propofol reduces discharge times compared with inhaled general anaesthesia in shoulder arthroscopy: a randomized controlled trial; The influence of obesity on outcomes following arthroscopic rotator cuff repair; Humeral component version has no effect on outcomes following reverse total shoulder arthroplasty: a prospective, double-blinded, randomized controlled trial; What is a meaningful improvement after total shoulder arthroplasty by implant type, preoperative diagnosis, and sex?; The safety of corticosteroid injection prior to shoulder arthroplasty: a systematic review; Mortality and subsequent fractures of patients with olecranon fractures compared to other upper limb osteoporotic fractures.

Aims

Giant cell tumours (GCTs) of the proximal femur are rare, and there is no consensus about the best method of filling the defect left by curettage. In this study, we compared the outcome of using a fibular strut allograft and bone cement to reconstruct the bone defect after extended curettage of a GCT of the proximal femur.

The orthopaedic surgeon is often consulted to manage pathologic fractures due to metastatic disease, even though he or she may not be an orthopaedic oncologist. A good understanding of the principles of management of metastatic disease is therefore important. The skeleton remains a common site for metastasis, and certain cancers have a predilection for bone, namely, tumors of the breast, prostate, lung, thyroid, and kidney. Myeloma and lymphoma also often involve bone. The proximal femur and pelvis are most commonly affected, so we will focus on those anatomic sites. The patient may present with pain and impending fracture, or with actual fracture. Careful preoperative medical optimization is recommended. If the lesion is solitary, or the primary is unknown, the diagnosis must be made by a full workup and biopsy before definitive treatment is planned. For patients with known metastasis (the most common situation), the options for treatment of pathologic lesions of the proximal femur generally center on internal fixation versus prosthetic replacement. Patients with breast or prostate metastasis can live for several years after pathologic fracture, so constructs must be relatively durable. If fixation is chosen, it must be stable enough to allow full weight bearing, since the overwhelming majority of pathologic fractures will never heal. In general, long constructs are chosen to protect the entire length of the bone. Nails should protect the femoral neck as well, so cephalomedullary devices are typically chosen. Megaprostheses can be useful in situations where bony destruction precludes stable internal fixation. Postoperative radiation is recommended after wound healing. Acetabular involvement typically requires reinforcement rings or cement augmentation with the Harrington technique. Careful multi-disciplinary medical management is recommended to minimise complications

Aims

The aim of this study was to describe the management and associated outcomes of patients sustaining a femoral hip periprosthetic fracture (PPF) in the UK population.

The August 2023 Knee Roundup³⁶⁰ looks at: Curettage and cementation of giant cell tumour of bone: is arthritis a given?; Anterior knee pain following total knee arthroplasty: does the patellar cement-bone interface affect postoperative anterior knee pain?; Nickel allergy and total knee arthroplasty; The use of artificial intelligence for the prediction of periprosthetic joint infection following aseptic revision total knee arthroplasty; Ambulatory unicompartmental knee arthroplasty: development of a patient selection tool using machine learning; Femoral asymmetry: a missing piece in knee alignment; Needle arthroscopy – a benefit to patients in the outpatient setting; Can lateral unicompartmental knees be done in a day-case setting?

Aims

To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI).

Aims

Despite limited clinical scientific backing, an additional trochanteric stabilizing plate (TSP) has been advocated when treating unstable trochanteric fractures with a sliding hip screw (SHS). We aimed to explore whether the TSP would result in less post operative fracture motion, compared to SHS alone.

Aims

Revision rates for ankle arthroplasties are higher than hip or knee arthroplasties. When a total ankle arthroplasty (TAA) fails, it can either undergo revision to another ankle replacement, revision of the TAA to ankle arthrodesis (fusion), or amputation. Currently there is a paucity of literature on the outcomes of these revisions. The aim of this meta-analysis is to assess the outcomes of revision TAA with respect to surgery type, functional outcomes, and reoperations.

Introduction: Despite the lack of good clinical evidence post operative radiotherapy is standard practice following non radical surgical treatment of skeletal metastases in long bones There is little in the literature about the size of radiation field and whether the whole bone, the nail or just the area of the metastatic deposit should be covered. Methods: We present two cases where the metastases were treated by intramedullary nailing and were subsequently irradiated. In each case the tip of the intramedullary nail was outside the radiotherapy field. Results: Subsequent second metastasis formation occurred at the tip of the nail compounded by pathological fracture. Salvage surgery was achieved in one case with a total femoral replacement and in the other by bi-columnar plating of the humerus with cement augmentation. Discussion: Intramedullary nailing of a metastasis will seed the tumour to the tip of the nail. It is therefore essential that the tip of the nail be included in the radiotherapy field post-operatively as salvage surgery for subsequent pathological fracture is technically demanding. The aim of any surgery for skeletal metastases is that the reconstruction should outlast the patient. Communication between surgeon and radiation oncologist is essential

Introduction: Spine fractures are common manifestation of osteoporosis. After an acute osteoporotic vertebral compression fracture pain persisting even after 3 months and clinical tenderness should raise the suspicion of pseudarthrosis. Pseudarthrosis is not a rare complication of a benign osteoporotic vertebral collapse occurs in about 10% of cases after an acute collapse. Treatment plan needs to be individualized. Cement augmentation procedures such as kyphoplasty and vertebroplasty can be performed in the absence of neurological deficit, whereas decompression and stabilization is necessary in presence of neurological deficit. Study Design: Prospective cohort study. Methods: 31 patients who were diagnosed to have an acute osteoporotic vertebral compression fracture were managed conservatively. Pain persisting after 3 months and clinical tenderness in 5 patients prompted further investigation, revealing pseudarthrosis. None of them had neurological deficit. Imaging of two patients revealed vacuum sign with intravertebral cleft on plain radiographs and on MRI. All of them were at the Dor-solumbar junction and of crush typeof VCF. Results: The incidence of pseudoarthrosis after an oste-porotic VCF was found to be 16.12%. One patient was treated with kyphoplasty, one with vertebroplasty with good pain relief and restoration of functional ability, and rest three are awaiting kyphoplasty. Conclusion: High suspicion of pseudarthrosis is to be kept in mind as it is not an uncommon complication of benign osteoporotic collapse. Vertebral augmentation procedures such as kyphoplasty and vertebroplasty are promising procedures for treatment in absence of neurological deficit

Introduction: Percutaneous kyphoplasty is a minimally invasive, radiologically guided procedure in which bone cement is injected into structurally weakened or destructed vertebrae. In addition to treating osteoporotic vertebral fractures, this technique gains popularity to relieve pain by stabilizing vertebrae compromised by, for example, metastases, aggressive hemangiomas or multiple myeloma that are at risk of pathologic fracture. Materials and Methods: Retrospective study including 44 patients (67 fractures) who undergone percutaneous kyphoplasty from one or several tumoral fractures of the spine between January 2006 and February 2009. 77% were female. The mean age was 67. VAS scale and Karnofsky index were both measured pre and postoperatively. The most frequent lesion found was metastases from a primary tumor followed by myeloma. Results: All patients were seated 24 hours after surgery. Partial or complete pain relief was obtained in 91% of patients (40/44); significant results were also obtained with regard to improvement in functional mobility and reduction of analgesic use. The mean value of the visual analogue scale (VAS) was 5.9 preoperatively, and significantly decreased to 3.3 one day after kyphoplasty. We reported 4 new vertebral fractures and no cases of cement extrusion during the follow-up. We didn’t report any case of neurological dysfunction after surgery. Discussion: Most cases in our study show a significant improvement in pain and functionality with no associated complications. Kyphoplasty cement augmentation has been a safe and effective method in the treatment of symptomatic vertebral neoplasic compression fractures

Objective: In 1989 Mirels published a scoring system for identifying impending pathological fractures in long bones. However, the spine is the most common site of skeletal metastases. A MR-based scoring system is proposed to quantify the risk of sustaining a pathological fracture through a metastatic lesion in a vertebral body. Methods: A retrospective analysis of 101 vertebral body metastatic lesions was carried out. The metastases were identified through the onco-radiology database. Only lesions with a MR scan and subsequent imaging within 24-months of the index scan were included. Variables potentially predictive of impending fracture were analysed for significance. The significant variables were then statistically weighted. The original MR scans were scored, and the subsequent imaging was used to identify which lesions fractured. The scores were compared between the fracture and non-fracture group. Analysis was carried out for each predictive variable to establish whether they were individually as good as the scoring system alone in predicting fracture. Intra and inter-observer variability was assessed using kappa statistics. Results: Twenty-one of the 101 lesions fractured within 24 months. A mean score of 0.65 was identified in the non-fracture group, whilst the fracture group had a mean score of 6.52 (p< 0.0001). The percentage risk of a lesion sustaining a pathological fracture was calculated for any given score. As the score increased above 4, so did the percentage risk of fracture (sensitivity 85.7%, specificity 97.5%). Very good intra and inter-observer agreement was present, showing the scoring system to be reliably reproducible. Conclusions: The authors propose that all painful vertebral body metastatic lesions be evaluated by MR scanning. Lesions with a score of 3 or less can be left untreated. Lesions with scores of 4 or higher are at risk of fracture and should be considered for prophylactic cement augmentation

Acute osteoporotic vertebral compression fractures (VCFs) are frequently misdiagnosed as there is often no history of preceding trauma. VCFs not only cause back pain, but can also result in a loss of function, spinal deformity and increased mortality. Cement augmentation has been shown to effectively treat these fractures. It is impossible to diagnose an acute fracture on plain x-ray and therefore identify those likely to benefit from this treatment. The definitive investigation to determine the presence of an acute fracture is a MR scan, but this is a limited resource. The aim of this paper is to evaluate 2 new clinical signs which we believe aid in the diagnosis of an acute VCF: firstly closed fist percussion at the level of an acute VCF resulting in a severe, sharp fracture pain, and secondly the inability of a patient to lie supine. This was a prospective study of 78 patients with suspected acute VCFs. 48/78 had an acute fracture on MR. 42/45 patients who were positive for closed fist percussion, had an acute fracture on their MR scan. There were 6 patients who were negative for closed fist percussion who had an acute fracture (sensitivity 87.5%, specificity 90%). 39/41 patients who were positive for the supine sign had an acute fracture on their MR scan. There were 9 patients who were comfortably able to lay supine who had an acute fracture (sensitivity 81.25%, specificity 93.33%). Either a positive closed fist percussion sign or a positive supine sign is a reliable indicator of the presence of an acute VCF. By incorporating these signs into our routine clinical assessment we are better able to predict which patients have an acute fracture, and therefore decide which patients need a MR scan

The humerus is a common site for metastasis. Intramedullary nail fixation has been reported to be the best form of fixation for this disease but complications with this procedure have been reported. This study reports on the results of using a new humeral nail for the treatment of pathological fracture or impending fracture of the humerus. Twenty nine patients had 31 Austofix humeral nails, 25 for pathological fracture and 6 for impending fracture. Twenty-four nails were inserted anterograde and 7 retrograde. Cement augmentation was used in 4 patients. Adjuvant therapy was used in 26 patients. One patient was lost to follow-up. Fixation failed in six patients, two due to intra-operative fractures during retrograde insertion, one due to fracture through screw holes postoperatively, and three due to local progression of disease. Difficulties in locking the nail distally were encountered in an additional 3 patients. In conclusion, in the majority of patients, nailing of the humerus with metastatic disease resulted in a stable humerus. Retrograde nailing of the humerus was associated with an increased risk of intra-operative fracture. Adjuvant therapy cannot be relied upon to prevent loss of fixation due to local progression of disease. The longest possible nail should be inserted through the antegrade route and locked to minimise the risk of loss of fixation

Endoprosthetic replacement is often the preferred treatment for neoplastic lesions as internal fixation has been shown to have a high failure rate. Due to anatomical location, disease factors and patient factors internal fixation may be the treatment of choice. No reports exist in the literature regarding the use of locking plates in the management of neoplastic long bone lesions. Data was collected prospectively on the first 10 patients who underwent locking plate fixation of neoplastic long bone lesions. Data was collected on the nature of the lesion, surgery performed, complications and outcome. The patients mean age was 56.6 (15–88). Six lesions were metastatic, one haematological (myeloma) and 3 were primary bone lesions (lymphoma, Giant cell tumour, simple bone cyst). In nine cases a fracture through the lesion had occurred. Anatomical locations of the lesions were; proximal humerus (four), proximal tibia (three), distal femur (two) and distal tibia (one). Cement augmentation of significant bone defects was necessary in seven cases. The mean hospital stay was 8 days (3–20). There were no inpatient complications. Five patients received adjuvant radiotherapy and one patient received neo-adjuvant radiotherapy to the lesion. There have been 3 deaths. All were due to metastatic disease and occurred between 6 and 12 months after surgery. The mean follow up in the surviving patients is currently 9 months (5–16). There have been no fixation related complications. Patients who had suffered a fracture had restoration of their WHO performance status. At last follow up the mean MSTS was 78% (57–90) for lower limb surgery and 70% (63–76) for upper limb surgery. These figures compare favourably with the results of endoprosthetic replacement. The early results of locking plate fixation for neoplastic long bone lesions are excellent. Follow up continues to observe how these devices perform in the long term

Introduction: Percutaneous vertebroplasty (PVP) is a treatment option for osteoporotic vertebral compression fractures (VCFs). Short-term results are promising but longer-term studies have demonstrated an accelerated failure rate in the adjacent vertebral body (VB). Limited research has been conducted into the effects of prophylactic PVP in osteoporotic vertebrae. The objective of this study was to investigate the biomechanical characteristics of prophylactic vertebral reinforcement and post-fracture augmentation. Methods: Human vertebrae were assigned to two scenarios: Scenario 1 used an experimental model for simulating VCFs followed by cement augmentation; Scenario 2 involved prophylactic augmentation using vertebroplasty. μCT imaging was performed to assess the bone mineral density (BMD), vertebral dimensions, fracture pattern and cement volume. All augmented VBs were then axially compressed to failure. Results: Product of BMD value and endplate surface area gave the best prediction of failure strength when compared to actual failure strength of specimens in scenario 1. Augmented VBs showed an average cement fill of 23.9%±8.07% S.D.. In scenario 1, there was a significant post-vertebroplasty factorial increase of 1.72 and in scenario 2 a 1.38 increase in failure strength. There was a significant reduction in stiffness following augmentation for scenario 1 (t=3.5, P=0.005). Stiffness of the VB in scenario 2 was significantly greater than observed in scenario 1 (t=4.4, P=0.0002). Discussion: Results suggest that augmentation of the VB post-fracture significantly increases failure load, whilst stiffness is not restored. Prophylactic augmentation was seen to increase failure strength in comparison to the predicted failure load. Stiffness appears to be maintained suggesting that prophylactic PVP maintains stiffness better than PVP post-fracture

A 52 year old male presented with a pathological subtrochanteric femoral fracture secondary to multiple myeloma. While stabilising the fracture with a Long Proximal Femoral Nail (PFN) distal femur fracture occurred, while introducing the distal locking screw, which was fixed with two cables. Partial weight bearing was allowed for the first six weeks. Three months after surgery the distal static locking screw broke. Eighteen months post surgery patient developed sudden spontaneous right hip pain and was treated with further chemotherapy and radiotherapy. Radiographs showed the fracture had not healed but there was no evidence of implant failure. Two years later patient presented with sudden increase in right hip pain with inability to walk. Radiographs showed that the nail had broken at the proximal hip screw hole. At revision surgery, with difficulty the broken distal locking screws were removed and the broken nail was removed by pushing it from below through the knee. The non union was stabilised with another long PFN. At four months post revision surgery there were radiological signs of bone healing and patient had no symptoms. Discussion: Reconstruction nails such as long PFN are bio mechanically suited for proximal femoral fractures and metastases. Bone cement augmentation has been reported to provide additional support in metastases. Dynamisation of the fracture leads to fracture impaction and promotes fracture healing. In this case implant failure was probably due to non union and fatigue failure of the implant. In spite of ‘spontaneous’ dynamisation (broken static distal screw), union did not occur initially. This is the first reported incidence of failure of long PFN in a pathological femoral fracture stabilisation

Vertebral fracture (VF) is a common complication of osteoporosis. Patients with osteoporotic VFs are often without symptoms and many of these fractures are detected by chance. Only one third of VFs is clinically diagnosed. However, osteoporotic VFs may also be very painful and cause severe discomfort during several weeks. In both genders low bone mineral density (BMD), prevalent VF and increasing age are strong predictors of VF. About one fifth of the patients with a VF suffer a new VF during the following year. Clinical consequences of VF include acute and chronic back pain, decreased quality of life and increased mortality. The care of patients with VF includes proper pain management and early rehabilitation. The use of elastic lumbosacral brace reduces pain when mobilising patient after VF. Calcitonin has been shown to have an analgetic effect. Sometimes the vertebral fracture causes a diagnostic problem and reasons other than osteoporosis should be ruled out (e.g. myeloma, lymphoma, metastases, other malign diseases). If feasible, the diagnosis of osteoporosis should be confirmed by BMD measurement. Osteoporotic VFs are seldom unstable requiring operative treatment. In case of neurological complications operative decompression and stabilisation should be considered. Impaired bone quality causes problems in pedicle screw fixation. Cement augmentation and special anchorage screws may provide increase in holding power in osteoporotic bone. Percutaneous vertebroplasty and balloon kyphoplasty are mini-invasive procedures that provide immediate and long lasting pain relief in VF patients. These techniques are technically demanding and require careful patient selection. Recent, prospective, randomized studies have shown that antiresorptive drugs can prevent new fractures in patients who had experienced previous fractures

Introduction: Cement augmentation of osteoporotic vertebral fractures by vertebroplasty can alleviate pain, although the mechanism remains unknown. We hypothesise that vertebral fracture reduces loading by the vertebral body, and that vertebroplasty reverses this effect. Methods: Nineteen thoracolumbar motion segments (64 – 90 yrs) were used. Specimens were compressed at 1.5kN in moderate flexion and extension while intradis-cal stress profiles were obtained by pulling a miniature pressure transducer along the mid-sagittal diameter of the disc (. 1. ). Vertebral fracture was induced by compressive overload in moderate flexion. Vertebroplasty was then performed by injecting polymethylmethacry-late cement into the anterior vertebral body. Stress profiles were repeated after fracture, and after vertebroplasty. Stress concentration in the annulus was calculated by subtracting the nuclear pressure from the maximum stress in the annulus. Neural arch compressive load was obtained by subtracting the disc compressive force, calculated by integrating intradiscal stress over area, from the applied 1.5kN (. 1. ). Results: Fracture increased the stress concentration in the annulus from 0.21 to 0.58MPa in flexion (p< 0.01) and from 0.02 to 0.20MPa in extension (p< 0.05). It also increased neural arch load bearing from 9% to 27% of the applied load in flexion (p< 0.01), and from 53% to 70% in extension (p< 0.01). Following vertebroplasty, these changes were largely reversed: in flexion, stress concentrations in the annulus decreased to 0.36MPa and neural arch load-bearing fell to 5% (p< 0.01). Similar, non-significant trends were observed in extension. Discussion: Vertebral fracture reduces load-bearing by the vertebral body, and increased compressive loading of the neural arch. Vertebroplasty goes some way to reversing these effects, and significantly decreased stress concentration in the annulus and loading of the neural arch in flexion. This could contribute to pain relief in patients undergoing this procedure

A biomechanical study assessing pedicle screw fixation with three different augmentation methods was performed in human cadaveric vertebrae. Precision opto-electronic measurement of screw motion assessed motion magnitude and patterns, ie translation and/or rotation. Physiological cyclic loads were applied as opposed to the simple pull out test. Augmentation with wires, hook or cement decreased overall motion. There were no significant differences in motion magnitude between the three augmentation methods. Motion patterns for screws with cement augmentation were mainly rotational and differed from the other two methods. Rigid body translations were observed with wires or hook augmentation, suggesting a loosening behaviour. Augmentation with cement resulted in better fixation than wires or hook. Augmentation of loosened pedicle screws in poor quality bone is often necessary. The purpose of this study was to contrast the kinematics of loosened pedicle screws augmented with laminar hooks, sublaminar wires or calcium phosphate cement. Cyclic tests of pedicle screws with compressive force and bending moment were carried out on forty-eight screws in twenty-four cadaveric vertebrae (L3-L5) augmented with hooks, wires or cement. Motion at the screw tip and screw head were measured using an optoelectronic camera system and the magnitudes compared in a paired manner using non-parametric statistics. Motion patterns of the screws were determined for each augmentation method. Augmentation with hook, wire or cement decreased screw motion. There was no significant difference between augmentation methods when the magnitudes of motion, described as ranges and offsets, were compared. Augmentation with cement resulted in mainly rotations of the screws while there were rigid body translations with wires or hooks. Comparing magnitudes of motion at the screw head and screw tip were insufficient. The screw head and screw tip could be moving in synchronous, indicating rigid body translations. Using simple pull out tests would not detect such differences. The method used in this study contrasted pedicle screws motion with different augmentations. While there was no detected significant difference in motion magnitude of the pedicle screws, the motion pattern of the screws suggested better augmentation with cement. Motion of pedicle screws in situ had not been described in the literature. Previous work comparing pedicle screws fixation used the pull out test, while the current method applied physiological loads. Funding: Funding from the Canadian Institutes for Health Research, Funding from Synthes. Spine Please contact author for diagrams and/or graphs

Percutaneous vertebroplasty (PVP) is an emerging interventional technique for treatment of vertebral compression fractures. Bone cement is introduced to mechanically augment fracture and pain relief is almost immediate. Recent clinical and biomechanical studies have outlined the phenomenon of fractures occurring in adjacent vertebrae following PVP [. 1. ,. 2. ]. It is widely believed that rigid cement augmentation may cause a shift in the normal loading pattern of the spine thereby resulting in adjacent fractures. However, very few studies have attempted to quantify this effect [. 3. ]. Most biomechanical studies adopt a single vertebral body as a model for PVP analysis. With this approach it is not possible to determine the effect of load distribution on adjacent structures. Where multi-segment vertebrae have been used there is little documentation of the fracture characteristics produced or their repeatability. The purpose of this study was to develop a 3-vertebra model for the biomechanical analysis of PVP. The particular focus was on developing a robust technique for generating repeatable level of fracture severity from specimen to specimen. An alignment device was developed to fit into standard materials testing machine, which allowed constant axial compression without causing lateral bending or flexion-extension of the specimen’s ends. Porcine 3-segment specimens (T8-L2) were mechanically compressed to failure at a rate of 5mm/min applied vertically at a distance of 35% to the anterior edge of the specimen’s anterior-posterior length. During the test load-displacement data was displayed in real time on a PC. In order to generate uniform fractures, a protocol was devised in which the specimens were compressed for a further 6mm after initial yield point. After the initial fracture the segments were augmented with 3ml of PMMA cement injected through each pedicle and then recompressed. The fracture characteristics generated under these conditions were analysed using quantitative microcomputer tomogragy (μCT). μCT images showed that fractures were generated in the central vertebra, with some propagation towards adjacent vertebra. The results support the use of a 3-segment specimen as a better representation for PVP analysis. The method will enables the load shift and fracture progression on either side of the augmented vertebra to be observed, thereby providing a more complete picture of load-bearing kinetics. Secondly, the middle, augmented motion segment remains unconstrained by platens and cement impressions; hence its anatomical boundary conditions are less compromised. Although longer segments have been shown to be more anatomically appropriate, it is difficult to apply physiologic levels of load without causing the specimen to buckle. We were able to minimise buckling effect by incorporating an alignment device to position the specimen without constraint. Given the preceding observations, the concepts of 3-segment specimen in PVP biomechanical tests provides a suitable compromise in choosing an appropriate clinical setting for in-vitro testing of biological spine specimens

Introduction: Cement augmentation of osteoporotic vertebral fractures by vertebroplasty can alleviate pain, possibly by restoring normal load-sharing to the affected motion segment. Fracture is known to decrease vertebral compressive stiffness (. 1. ), and also affects the compressive stress distribution acting on the vertebral body, causing stress concentrations to appear in the adjoining intervertebral discs (. 2. ). We hypothesise that vertebro-plasty can reverse these fracture-induced changes. Methods: Nineteen cadaver thoraco-lumbar motion segments (64–90 yrs) were used. Each was mounted on a hydraulic materials testing machine and induced to fracture by compressive overload in moderate flexion. Vertebroplasty was performed by injecting 7 cc of poly-methylmethacrylate cement (Simplex P, Stryker Howmedica, NJ) into the fractured vertebral body. Specimens were then creep loaded at 1.5 kN for 1 hour to allow consolidation. Before and after each procedure, profiles of the compressive stress distribution were obtained by pulling a miniature pressure transducer along the mid-sagittal diameter of the intervertebral disc whilst it was compressed at 1.5kN. Using these profiles, stress peaks in the anterior and posterior annulus were measured by subtracting the nucleus pressure from the peak stress in each region (. 2. ). Compressive stiffness of the motion segment was also measured before and after vertebroplasty from the tangent of the load-displacement curve at 1 kN. Changes were compared using ANOVA. Results: Following fracture, motion segment compressive stiffness was reduced by 37% from 2478 N/mm, STD 966N/mm, to 1583 N/mm, STD 585 N/mm (p = 0.0001), stress peaks in the posterior annulus were increased by 139% from 0.24 MPa, STD 0.24 MPa, to 0.57 MPa, STD 0.47 MPa (p = 0.016), and stress peaks in the anterior annulus showed no significant change. The decrease in compressive stiffness was significantly correlated with the increase in the size of the posterior stress peak (Rsq = 0.65, p< 0.001). Following vertebroplasty and subsequent creep loading, compressive stiffness was increased to 2156 N/mm, STD 718 N/mm, and stress peaks in the posterior annulus were reduced to 0.31 MPa, STD 0.43 MPa. These changes were again highly correlated with each other (Rsq = 0.68, p< 0.001). Both compressive stiffness and the size of posterior stress peaks after vertebroplasty showed no significant difference when compared to pre-fracture values. Discussion: Fracture reduces the ability of vertebrae to resist deformation, thereby decreasing compressive stiffness. These changes impair the disc’s ability to press evenly on the vertebral body, giving rise to increased stress peaks in the posterior annulus. Vertebroplasty can reverse these fracture induced changes by increasing vertebral compressive stiffness which acts to restore pressure in the nucleus. This enables the disc to press more evenly on the vertebral body and thereby reduces the size of stress peaks in the posterior annulus. This restoration of normal load-sharing may possibly contribute to pain relief in patients undergoing this procedure

Aims

The aim of this study was to present the long-term surgical outcomes, complications, implant survival, and causes of implant failure in patients treated with the modified Harrington procedure using antegrade large diameter pins.

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We investigated patient characteristics and outcomes of Vancouver type B periprosthetic fractures treated with femoral component revision and/or osteosynthesis.

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The aim of this study was to evaluate the clinical and radiological outcomes of locking plate fixation, with and without an associated fibular strut allograft, for the treatment of displaced proximal humeral fractures in elderly osteoporotic patients.

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Intercalary allografts following resection of a primary diaphyseal tumour have high rates of complications and failures. At our institution intercalary allografts are augmented with intramedullary cement and fixed using compression plating. Our aim was to evaluate their long-term outcomes.

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Fractures of the distal femur can be challenging to manage and are on the increase in the elderly osteoporotic population. Management with casting or bracing can unacceptably limit a patient’s ability to bear weight, but historically, operative fixation has been associated with a high rate of re-operation. In this study, we describe the outcomes of fixation using modern implants within a strategy of early return to function.

Aims

Pelvic reconstruction after the resection of a tumour around the acetabulum is a challenging procedure due to the complex anatomy and biomechanics. Several pelvic endoprostheses have been introduced, but the rates of complication remain high. Our aim was to review the use of a stemmed acetabular pedestal cup in the management of these patients.

The April 2015 Oncology Roundup³⁶⁰ looks at: New hope for skull base tumours; Survival but at what cost?; Synovial sarcoma beginning to be cracked?; Wound complications facing soft-tissue sarcoma surgeons; Amputation may offer no survival benefit over reconstruction; Giant cell tumour in the longer term; Intralesional treatment comparable with excision in GCT of the radius?; Imaging prior to oncological referral; And finally…

Aims

Patients with multiple myeloma (MM) develop deposits in the spine which may lead to vertebral compression fractures (VCFs). Our aim was to establish which spinopelvic parameters are associated with the greatest disability in patients with spinal myeloma and VCFs.

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Surgical intervention in patients with bone metastases from breast cancer is dependent on the estimated survival of the patient. The purpose of this paper was to identify factors that would predict survival so that specific decisions could be made in terms of surgical (or non-surgical) management.

The October 2015 Spine Roundup360 looks at: Traumatic spinal cord injury under the spotlight; The odontoid peg nonunion; Driving and spinal surgery; Drains and antibiotics post-spinal surgery; Vertebroplasty and kyphoplasty equally effective; Who will benefit from steroid injections?; Back pain following lumbar discectomy

Many tumors metastasise to bone, therefore, pathologic fracture and impending pathologic fractures are common reasons for orthopedic consultation. Having effective treatment strategies is important to avoid complications, and relieve pain and preserve function. Thorough pre-operative evaluation is recommended for medical optimization and to ensure that the lesion is in fact a metastasis and not a primary bone malignancy. For impending fractures, various scoring systems have been proposed to determine the risk of fracture, and therefore the need for prophylactic stabilisation. Lower score lesions can often be treated with radiation, while more problematic lesions may require internal fixation. Intramedullary fixation is generally preferred due to favorable biomechanics. Arthroplasty may be required for lesions with massive bony destruction where internal fixation attempts are likely to fail. Radiation may also be useful postoperatively to minimise construct failure due to tumor progression.

Aims

The aims of this study were to evaluate the clinical and radiological outcomes of instrumented posterolateral fusion (PLF) performed in patients with rheumatoid arthritis (RA).

The aim of this study was to quantify the stability of fracture-implant complex in fractures after fixation. A total of 15 patients with an undisplaced fracture of the femoral neck, treated with either a dynamic hip screw or three cannulated hip screws, and 16 patients with an AO31-A2 trochanteric fracture treated with a dynamic hip screw or a Gamma Nail, were included. Radiostereometric analysis was used at six weeks, four months and 12 months post-operatively to evaluate shortening and rotation.

Migration could be assessed in ten patients with a fracture of the femoral neck and seven with a trochanteric fracture. By four months post-operatively, a mean shortening of 5.4 mm (-0.04 to 16.1) had occurred in the fracture of the femoral neck group and 5.0 mm (-0.13 to 12.9) in the trochanteric fracture group. A wide range of rotation occurred in both types of fracture. Right-sided trochanteric fractures seem more rotationally stable than left-sided fractures.

This prospective study shows that migration at the fracture site occurs continuously during the first four post-operative months, after which stabilisation occurs. This information may allow the early recognition of patients at risk of failure of fixation.

Cite this article: Bone Joint J 2015;97-B:391–7.

Failure of fixation is a common problem in the treatment of osteoporotic fractures around the hip. The reinforcement of bone stock or of fixation of the implant may be a solution. Our study assesses the existing evidence for the use of bone substitutes in the management of these fractures in osteoporotic patients. Relevant publications were retrieved through Medline research and further scrutinised. Of 411 studies identified, 22 met the inclusion criteria, comprising 12 experimental and ten clinical reports. The clinical studies were evaluated with regard to their level of evidence. Only four were prospective and randomised.

Polymethylmethacrylate and calcium-phosphate cements increased the primary stability of the implant-bone construct in all experimental and clinical studies, although there was considerable variation in the design of the studies. In randomised, controlled studies, augmentation of intracapsular fractures of the neck of the femur with calcium-phosphate cement was associated with poor long-term results. There was a lack of data on the long-term outcome for trochanteric fractures. Because there were only a few, randomised, controlled studies, there is currently poor evidence for the use of bone cement in the treatment of fractures of the hip.

We set out to determine the impact of surgery on quality of life and function in patients who had undergone surgery for symptomatic peri-acetabular metastases. From a prospective database we retrospectively reviewed 46 consecutive patients who had been treated operatively between June 2003 and June 2009. The mean age of the patients was 56.4 years (20 to 73) and the mean post-operative follow-up was 19.2 months (4 to 70). Functional evaluation and quality-of-life assessments were performed. At the most recent follow-up, 26 patients (56.5%) were alive. Their median survival time was 25.0 months. Ten major postoperative complications had occurred in eight patients (17.4%). The mean post-operative Musculoskeletal Tumor Society score (MSTS 93) was 56.3% (6.7% to 90.0%). Improvement in the Eastern Cooperative Oncology Group (ECOG) performance status was seen in 32 patients (69.6%). On the European Organisation for Research and Treatment of Cancer core quality-of-life questionnaire (QLQ-C30) measure of global health status there was a statistically significant improvement from the patients’ pre-operative status (42.8 (sd 13.7)) to that found at the latest follow-up (58.0 (sd 12.5)) (p = 0.001). The only statistically significant change in the nine symptom domains of the QLQ-C30 was a reduction in the mean level of pain (from 59.1 to 29.5 (out of 100)) (p < 0.001).

Surgery for patients with peri-acetabular metastases reduces pain and improves their quality of life, and has a low rate of surgical complications.

Bone loss secondary to primary or metastatic lesions of the proximal humerus remains a challenging surgical problem. Options include preservation of the joint with stabilisation using internal fixation or resection of the tumour with prosthetic replacement. Resection of the proximal humerus often includes the greater tuberosity and adjacent diaphysis, which may result in poor function secondary to loss of the rotator cuff and/or deltoid function. Preservation of the joint with internal fixation may reduce the time in hospital and peri-operative morbidity compared with joint replacement, and result in a better functional outcome. We included 32 patients with pathological fractures of the proximal humerus in this study. Functional and radiological assessments were performed. At a mean follow-up of 17.6 months (8 to 61) there was no radiological evidence of failure of fixation. The mean revised musculoskeletal Tumour Society functional score was 94.6% (86% to 99%). There was recurrent tumour requiring further surgery in four patients (12.5%). Of the 22 patients who were employed prior to presentation all returned to work without restrictions.

The use of a locking plate combined with augmentation with cement extends the indications for salvage of the proximal humerus with good function in patients with pathological and impending pathological fractures.

In this retrospective study we evaluated the proficiency of shelf autograft in the restoration of bone stock as part of primary total hip replacement (THR) for hip dysplasia, and in the results of revision arthroplasty after failure of the primary arthroplasty. Of 146 dysplastic hips treated by THR and a shelf graft, 43 were revised at an average of 156 months, 34 of which were suitable for this study (seven hips were excluded because of insufficient bone-stock data and two hips were excluded because allograft was used in the primary THR). The acetabular bone stock of the hips was assessed during revision surgery. The mean implant–bone contact was 58% (50% to 70%) at primary THR and 78% (40% to 100%) at the time of the revision, which was a significant improvement (p < 0.001). At primary THR all hips had had a segmental acetabular defect > 30%, whereas only five (15%) had significant segmental bone defects requiring structural support at the time of revision. In 15 hips (44%) no bone graft or metal augments were used during revision.

A total of 30 hips were eligible for the survival study. At a mean follow-up of 103 months (27 to 228), two aseptic and two septic failures had occurred. Kaplan-Meier survival analysis of the revision procedures demonstrated a ten-year survival rate of 93.3% (95% confidence interval (CI) 78 to 107) with clinical or radiological failure as the endpoint. The mean Oxford hip score was 38.7 (26 to 46) for non-revised cases at final follow-up.

Our results indicate that the use of shelf autografts during THR for dysplastic hips restores bone stock, contributing to the favourable survival of the revision arthroplasty should the primary procedure fail.

Cite this article: Bone Joint J 2013;95-B:777–81.

Bone defects are occasionally encountered during primary total knee replacement (TKR) and cause difficulty in establishing a stable well-aligned bone-implant interface. Between March 1999 and November 2005, 59 knees in 43 patients underwent primary TKR with a metal block augmentation for tibial bone deficiency. In all, six patients (eight knees) died less than four years post-operatively, and four patients (five knees) were lost to follow-up leaving 46 knees in 33 patients available for review at a mean of 78.6 months (62 to 129). The clinical results obtained, including range of movement, American Knee Society and Oxford knee scores, and the Western Ontario and McMaster Universities osteoarthritis index, were good to excellent, with no failures. Radiolucent lines at the block-cement-bone interface were noted in five knees (11%) during the first post-operative year, but these did not progress.

Modular rectangular metal augmentation for tibial bone deficiency is a useful option. No deterioration of the block-prosthesis or block-cement-bone interface was seen at minimum of five years follow-up.

Vertebral compression fractures are the most prevalent complication of osteoporosis and percutaneous vertebroplasty (PVP) has emerged as a promising addition to the methods of treating the debilitating pain they may cause.

Since PVP was first reported in the literature in 1987, more than 600 clinical papers have been published on the subject. Most report excellent improvements in pain relief and quality of life. However, these papers have been based mostly on uncontrolled cohort studies with a wide variety of inclusion and exclusion criteria. In 2009, two high-profile randomised controlled trials were published in the New England Journal of Medicine which led care providers throughout the world to question the value of PVP. After more than two decades a number of important questions about the mechanism and the effectiveness of this procedure remain unanswered.

There are three basic concepts that are important to the biomechanics of pedicle screw-based instrumentation. First, the outer diameter of the screw determines pullout strength, while the inner diameter determines fatigue strength. Secondly, when inserting a pedicle screw, the dorsal cortex of the spine should not be violated and the screws on each side should converge and be of good length. Thirdly, fixation can be augmented in cases of severe osteoporosis or revision.

A trajectory parallel or caudal to the superior endplate can minimise breakage of the screw from repeated axial loading. Straight insertion of the pedicle screw in the mid-sagittal plane provides the strongest stability.

Rotational stability can be improved by adding transverse connectors. The indications for their use include anterior column instability, and the correction of rotational deformity.

The management of bone loss in revision replacement of the knee remains a challenge despite an array of options available to the surgeon. Bone loss may occur as a result of the original disease, the design of the prosthesis, the mechanism of failure or technical error at initial surgery. The aim of revision surgery is to relieve pain and improve function while addressing the mechanism of failure in order to reconstruct a stable platform with transfer of load to the host bone. Methods of reconstruction include the use of cement, modular metal augmentation of prostheses, custom-made, tumour-type or hinged implants and bone grafting.

The published results of the surgical techniques are summarised and a guide for the management of bone defects in revision surgery of the knee is presented.

We have reviewed 54 patients who had undergone 61 total hip replacements using bulk femoral autografts to augment a congenitally dysplastic acetabulum. There were 52 women and two men with a mean age of 42.4 years (29 to 76) at the time of the index operation. A variety of different prostheses was used: 28 (45.9%) were cemented and 33 (54.1%) uncemented. The graft technique remained unchanged throughout the series.

Follow-up was at a mean of 8.3 years (3 to 20). The Hospital for Special Surgery hip score improved from a mean of 10.7 (4 to 18) pre-operatively to a mean of 35 (28 to 38) at follow-up.

The position of the acetabular component was anatomical in 37 hips (60.7%), displaced less than 1 cm in 20 (32.7%) and displaced more than 1 cm in four (6.6%). Its cover was between 50% and 75% in 34 hips (55.7%) and less than 50% in 25 (41%). In two cases (3.3%), it was more than 75%.

There was no graft resorption in 36 hips (59%), mild resorption in 21 (34%) and severe resorption in four (6%).

Six hips (9.8%) were revised for aseptic loosening. The overall rate of loosening and revision was 14.8%. Overall survival at 8.3 years was 93.4%.

The only significant factor which predicted failure was the implantation of the acetabular component more than 1 cm from the anatomical centre of rotation of the hip.

We report the clinical and radiographic outcome of a consecutive series of 138 hydroxyapatite-coated total knee replacements with a mean follow-up of 11 years (10 to 13). The patients were entered into a prospective study and all living patients (76 knees) were evaluated. The Hospital for Special Surgery knee score was obtained for comparison with the pre-operative situation. No patient was lost to follow-up. Radiographic assessment revealed no loosening. Seven prostheses have been revised, giving a cumulative survival rate of 93% at 13 years. We believe this to be the longest follow-up report available for an hydroxyapatite-coated knee replacement and the first for this design of Insall-Burstein II knee.

Vertebral haemangiomas are usually asymptomatic and discovered fortuitously during imaging. A small proportion may develop variable degrees of pain and neurological deficit. We prospectively studied six patients who underwent eight surgical procedures on 11 vertebral bodies. There were 11 balloon kyphoplasties, six lumbar and five thoracic. The mean follow-up was 22.3 months (12 to 36). The indications for operation were pain in four patients, severe back pain with Frankel grade C paraplegia from cord compression caused by soft-tissue extension from a thoracic vertebral haemangioma in one patient, and acute bleeding causing Frankel grade B paraplegia from an asymptomatic vascular haemangioma in one patient. In four patients the exhibited aggressive vascular features, and two showed lipomatous, non-aggressive, characteristics. One patient who underwent a unilateral balloon kyphoplasty developed a recurrence of symptoms from the non-treated side of the vertebral body which was managed by a further similar procedure.

Balloon kyphoplasty was carried out successfully and safely in all patients; four became asymptomatic and two showed considerable improvement. Neurological recovery occurred in all cases but bleeding was greater than normal. To avoid recurrence, complete obliteration of the lesion with bone cement is indicated. For acute bleeding balloon kyphoplasty should be combined with emergency decompressive laminectomy. For intraspinal extension with serious neurological deficit, a combination of balloon kyphoplasty with intralesional alcohol injection is effective.

We undertook a multicentre, prospective study of a series of 112 unstable trochanteric fractures in order to evaluate if internal fixation with a sliding screw device combined with augmentation using a calcium phosphate degradable cement (Norian SRS) could improve the clinical, functional and radiological outcome when compared with fractures treated with a sliding screw device alone. Pain, activities of daily living, health status (SF-36), the strength of the hip abductor muscles and radiological outcome were analysed.

Six weeks after surgery, the patients in the augmented group had significantly lower global and functional pain scores (p < 0.003), less pain after walking 50 feet (p < 0.01), and a better return to the activities of daily living (p < 0.05). At follow-up at six weeks and six months, those in the augmented group showed a significant improvement compared with the control group in the SF-36 score. No other significant differences were found between the groups. We conclude that augmentation with calcium phosphate cement in unstable trochanteric fractures provides a modest reduction in pain and a slight improvement in the quality of life during the course of healing when compared with conventional fixation with a sliding screw device alone.