The treatment of joint-fractures is a common task in orthopaedic surgery causing considerable health costs and patient disabilities. Percutaneous techniques have been developed to mitigate the problems related to open surgery (e.g. soft tissue damage), although their application to joint-fractures is limited by the sub-optimal intra-operative imaging (2D- fluoroscopy) and by the high forces involved. Our earlier research toward improving percutaneous reduction of intra-articular fractures has resulted in the creation of a robotic system prototype, i.e. RAFS (Robot-Assisted Fracture Surgery) system.

We propose a robot-bone attachment device for percutaneous bone manipulation, which can be anchored to the bone fragment through one small incision, ensuring the required stability and reducing the “biological cost” of the procedure. It consists of a custom-designed orthopaedic pin, an anchoring system (AS secures the pin to the bone), and a gripping system (GS connects the pin and the robot). This configuration ensures that the force/torque applied by the robot is fully transferred to the bone fragment to achieve the desired anatomical reduction.

The device has been evaluated through the reduction of 9 distal femur fractures on human cadavers using the RAFS system. The devices allowed the reduction of 7 fractures with clinical acceptable accuracy. 2 fractures were not reduced: in one case the GS failed and was not able to keep the pin stationary inside the robot (pin rotates inside the GS). The other fracture was too dislocated (beyond the operational workspace capability of the robot). A more stable GS will be designed to avoid displacements between the pin and the robot.

Background

Treating fractures is expensive and includes a long post-operative care. Intra-articular fractures are often treated with open surgery that require massive soft tissue incisions, long healing time and are often accompanied by deep wound infections. Minimally invasive surgery (MIS) is an alternative to this but when performed by surgeons and supported by X-rays does not achieve the required accuracy of surgical treatment.

Aims

Computer hexapod assisted orthopaedic surgery (CHAOS), is a method to achieve the intra-operative correction of long bone deformities using a hexapod external fixator before definitive internal fixation with minimally invasive stabilisation techniques.

The aims of this study were to determine the reliability of this method in a consecutive case series of patients undergoing femoral deformity correction, with a minimum six-month follow-up, to assess the complications and to define the ideal group of patients for whom this treatment is appropriate.

The implementation of knee arthrodesis has become synonymous with limb salvage in the presence of chronic sepsis and bone loss around the knee. This can be seen in failed trauma surgery or knee arthroplasty as an alternative to trans-femoral amputation. There is no prior literature assessing which factors affect knee arthrodesis using external fixation devices.

Sixteen consecutive patients (four women and twelve men) made up of eleven infected knee implants, three internal fixations of the tibial following fractured tibial plateau as well as 2 infected native joints were identified. The mean age at initial surgery was 56 years (range 25 to 82 years). All procedures were performed under the direct supervision of the limb reconstruction teams using a standard protocol with either a Taylor spatial frame or Ilizarov frame. The patient records, microbiology results and radiographs of all patients who underwent knee arthrodesis at this institution between 1999 and 2010 were reviewed.

Of the 16 patients in this study knee fusion occurred in eleven patients (69%). The five patients where arthrodesis failed all had significant bone loss on the pre-operative radiographs and confirmed at surgery. We found a relationship between a significant infection of the knee with MRSA and failure to fuse. Three of the five patients had MRSA isolated from inside the knee at some stage during their treatment.

The five patients where fusion failed were on average older (mean age 63 years against 51 years) and had more extensive bone loss. Those who failed to fuse had more co-morbidities. We would conclude that where there is little or no bone loss, arthrodesis of the knee can be reliably achieved with the use of circular frame fixation. A greater number of negative factors also prolongs the amount of time spent in the external fixator. The presence of significant bone loss, infection, increased age and multiple co-morbidities requires careful evaluation and consideration of trans-femoral amputation as an alternative.

One of the more difficult tasks in surgery is to apply the optimal instrument forces and torques necessary to conduct an operation without damaging the tissue of the patient. This is especially problematic in surgical robotics, where force-feedback is totally eliminated. Thus, force sensing instruments emerge as a critical need for improving safety and surgical outcome. We propose a new measurement system that can be used in real fracture surgeries to generate quantitative knowledge of forces/torques applied by surgeon on tissues.

We instrumented a periosteal elevator with a 6-DOF load-cell in order to measure forces/torques applied by the surgeons on live tissues during fracture surgeries. Acquisition software was developed in LabView to acquire force/torque data together with synchronised visual information (USB camera) of the tip interacting with the tissue, and surgeon voice recording (microphone) describing the actual procedure. Measurement system and surgical protocol were designed according to patient safety and sterilisation standards.

The developed technology was tested in a pilot study during real orthopaedic surgery (consisting of removing a metal plate from the femur shaft of a patient) resulting reliable and usable. As demonstrated by subsequent data analysis, coupling force/torque data with video and audio information produced quantitative knowledge of forces/torques applied by the surgeon during the surgery. The outlined approach will be used to perform intensive force measurements during orthopaedic surgeries. The generated quantitative knowledge will be used to design a force controller and optimised actuators for a robot-assisted fracture surgery system under development at the Bristol Robotics Laboratory.

We conducted a multicentre two arm double blind randomised controlled trial to assess efficacy of pulsed ultrasound for accelerating the rate of bone healing. Sixty-two skeletally mature adults undergoing limb lengthening, of between 2.5cm to 10cm by distraction osteogenesis, at the proximal tibia using an Ilizarov frame were randomised to either an active or a placebo (control) ultrasound device.

Primary outcome measure was time ready for removal of frame after adjusting for distraction length (days/cm) for both intension to treat (ITT) and per protocol (PP) patients. The time at which the frame was removed was determined by the maturation of the regenerate bone. Secondary outcomes were return to weight bearing and covariates affecting time to frame removal.

The baseline characteristics of the two groups were well balanced, and 90% of patients were managed and followed up as PP. There was no difference in the time to frame removal between the two groups for the ITT (5.0days/cm, p=0.23) or the PP (10.1days/cm, p=0.054). There was no difference in return to weight bearing between the two groups, after adjusting for distraction length, for the ITT or PP patients (p>0.5). Smoking was the only covariate identified to increase the frame removal time (hazard ratio 0.46, 95% confidence interval 0.22 to 0.96; p=0.04).

This trial demonstrated no difference in bone healing between those who underwent pulsed ultrasound and those who did not. Smoking was observed to have a significant inhibitory effect on bone healing.

Objective:

To assess efficacy of pulsed ultrasound for accelerating regenerate consolidation.

Percutaneous grafting of non-union using bone marrow concentrates has shown promising results, we present our experience and outcomes following the use of microdrilling and marrowstim in long bone non-unions.

We retrospectively reviewed all patients undergoing a marrowstim procedure for non-union in 2011–12. Casenotes and radiographs were reviewed for all. Details of injury, previous surgery and non-union interventions together with additional procedures performed after marrowstim were recorded for all patients. The time to clinical and radiological union were noted.

We identified 32 patients, in sixteen the tibia was involved in 15 the femur and in one the humerus. Ten of the 32 had undergone intervention for non-union prior to marrowstim including 4 exchange nailings, 2 nail dynamisations, 3 caption graftings, 2 compression in circular frame and 1 revision of internal fixation. Three underwent adjunctive procedures at the time of marroswstim. In 18 further procedures were required following marrowstim. In 4 this involved frame adjustment, 5 underwent exchange nailing, 4 revision internal fixation, 2 additional marrowstim, 2 autologous bone grafting and 3 a course of exogen treatment.

In total 27 achieved radiological and clinical union at a mean of 9.6 months, of these ten achieved union without requiring additional intervention following marrowstim, at a mean of 5.4 months. There were no complications relating to marrowstim harvest or application.

Marrowstim appears to be a safe and relatively cheap addition to the armamentarium for treatment of non-union. However many patients require further procedures in addition to marrowstim to achieve union. Furthermore given the range of procedures this cohort of patients have undergone before and after marrowstim intervention it is difficult to draw conclusions regarding it efficacy.

Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and dysfunction. Standard techniques are available to determine the centre of rotation of angulation (CORA) and extent of the majority of deformities, however distal femoral deformity is difficult to assess because of the difference between anatomic and mechanical axes. We found the described technique involving constructing a line perpendicular to a line from the tip of the greater trochanter to the centre of the femoral head inaccurate, particularly if the trochanter is abnormal. We devised a novel technique which accurately determines the CORA and extent of distal femoral deformity, allowing accurate correction.

Using standard leg alignment views of the normal femur, the distal femoral metaphysis and joint line are stylized as a block. A line bisecting the axis of the proximal femur is then extended distally to intersect the joint. The angle (θ) between the joint and the proximal femoral axis and the position (p) where the extended proximal femoral axis intersects the joint line are calculated. These measurements can then be reproduced on the abnormal distal femur in order to calculate the CORA and extent of the deformity, permitting accurate correction.

We examined the utility and reproducibility of the new method using 100 normal femora. θ = 81 ± sd 2.5°. As expected, θ correlated with femoral length (r=0.74). P (expressed as the percentage of the distance from the lateral edge of the joint block to the intersection) = 61% ± sd 8%. P was not correlated with θ.

Intra-and inter-observer errors for these measurements are within acceptable limits and observations of 30-paired normal femora demonstrate similar values for θ and p on the two sides.

We have found this technique to be universally applicable and reliable in a variety of distal femoral deformities.

Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and dysfunction. Standard techniques are available to determine the centre of rotation of angulation (CORA) and extent of the deformities. However, distal femoral deformity is difficult to assess because of the difference between anatomic and mechanical axes. We describe a novel technique which accurately determines the CORA and extent of distal femoral deformity.

Using standard leg alignment views of the normal femur, the distal femoral metaphysis and joint line are stylised as a block. A line bisecting the anatomical axis of the proximal femur is then extended distally to intersect the joint. The angle (?) between the joint and the proximal femoral axis, and the position (p) where the extended proximal femoral axis intersects the joint line are calculated. These measurements can then be reproduced on the abnormal distal femur in order to calculate the CORA and extent of deformity, permitting accurate correction.

We examined the utility and reproducibility of the new method using 100 normal femora. We found this technique to be universally robust in a variety of distal femoral deformities.

Introduction

The optimal management of intra-articular tibial plateau fractures with metaphyseal-diaphyseal dissociation remains challenging and controversial. We report results using the technique of limited open reduction with external fixation using a fine wire circular frame.

Methods: A Ring Fixator (Taylor Spatial Frame (TSF); Smith & Nephew, Memphis, TN), was used in the treatment of 5 patients (ages 11 to 16 years) with proximal tibial growth arrest following trauma.

Results: The mean corrections were 14.2° (max 28°, min 0°) in the saggital plane and 14° (max 38°, min 2°) in the coronal plane. Leg length discrepancy was also corrected (max 1cm). The average time in frame was 17.8 weeks, with an average correction time of 29.8 days. Knee Society Clinical Rating System (KSCRS) scores post operatively ranged from 95 to 100. All patients returned to full activity, and would accept the same treatment if offered again. The circular fixator is an effective, minimally invasive method for treating the complex deformities arising from this rare injury. Patients remain active during treatment, encouraging a rapid return to school/work activities.

A Ring Fixator (Taylor Spatial Frame (TSF); Smith & Nephew, Memphis, TN), was used in the treatment of 5 patients (ages 11 to 16 years) with proximal tibial growth arrest following trauma. The mean corrections were 14.20 (max 280, min 00) in the saggital plane and 140 (max 380, min 20) in the coronal plane. Leg length discrepancy was also corrected (max 1 cm). The average time in frame was 17.8 weeks, with an average correction time of 29.8 days. Knee Society Clinical Rating System (KSCRS) scores post operatively ranged from 95 to 100. All patients returned to full activity, and would accept the same treatment if offered again.

The circular fixator is an effective, minimally invasive method of treatment for post-traumatic proximal tibial deformity. Patients remain active during treatment encouraging a rapid return to school/work activities.

17 patients have undergone 20 microdrilling procedures to stimulate bone union in cases of established non-union. This occurred at the docking site following completion of bone transport using a stacked Taylor Spatial Frame, non-union following arthrodesis or non-union in long bone fracture.

Additional bone grafting was performed in only one patient. Further stimulation of union via injection of Bone Morphogenetic Protein was undertaken with 3 microdrilling procedures.

Of the 20 microdrilling procedures, 8 were considered fully successful in terms of stimulation of union, 7 were partially successful and 5 were not felt to have been successful.

The mean time to fully successful union following microdrilling was 11.4 weeks, ranging from 6 to 19 weeks.

There were 2 complications, both acute infections at the microdrilling site. Both of these were in patients with previous significant pin site infections.

We present the use of a microdrilling technique as a safe and effective minimally invasive technique that promotes union in cases of refractory non-union, whilst avoiding the donor site morbidity associated with open bone grafting.

We present, as a pilot study, our experience in the use of this technique in patients treated with circular frames for acute fractures, at the docking site in cases of bone transport and in cases of non-union following arthrodesis.

We have treated 17 patients with bone defects of the tibia by internal bone transport using a stacked Taylor Spatial Frame.

There were 12 cases of infected non unions, 2 cases of osteomyelitis, 1 case of acute traumatic bone loss, 1 case of non union in a patient with neurofibromatosis, and 1 case of pseudoarthrosis of the tibia.

The mean bone defect was 51.8mm (range 10–100mm).

Leg length has been restored to within 10mm in 16 cases and to within 15mm in one case. All patients have united.

Residual deformity at the docking site or regenerate was negligible in 4 patients and less than 5 degrees in any plane in the remaining 13 patients. There have been two cases of re-fracture which have united with conservative treatment and 1 case of partial peroneal nerve palsy which is recovering.

The use of a stacked Taylor Spatial Frame system is effective in mediating bone transport resulting in predictable regenerate, accurate docking and minimal induced bone deformity.

Complex regional pain syndrome (type 1) (CRPS) is a chronically painful and disabling condition commonly encountered following trauma and surgery to an extremity. The condition comprises of a combination of pain, swelling, sensory impairment, joint stiffness, trophic changes, motor abnormalities and vasomotor instability.

Post-traumatic CRPS is a significant clinical problem presenting to the orthopaedic surgeon and pain specialist. A clear understanding of the condition has been hampered by a lack of uniformity of diagnostic criteria (Van de Beek W-JT, et al Neurology2002;58:522–526). Pain therapists use the International Association of Pain (IASP) criteria (Bruehl S et al Pain1999;81:147–154) and orthopaedic surgeons the Atkins criteria (J Bone Joint Surg1990;72B:105–110).

Breuhl’s criteria use a combination of symptoms and signs from 4 distinct groups (hypersensitivity; vasomotor; swelling and sudomotor; motor and trophic).

Atkins’ criteria require the finding of vasomotor instability symptoms, abnormal finger dolorimetry and abnormal finger range of movements.

We have compared these different criteria on a series of 262 patients with distal radial fracture.

The incidence of CRPS was similar using either criteria (Bruehl 20.61% vs. Atkins 22.52%). Using the Bruehl criteria as a gold standard, there was strong diagnostic agreement (Kappa = 0.79, sensitivity = 0.87, specificity = 0.94). The main difference between the two methods was in pain assessment. 16 patients had vasomotor instability, swelling and motor changes but 12 did not complain of hypersensitivity although the dolorimetry ratio was lowered. These cases have CRPS by the Atkins criteria but not the Bruehl. In contrast 4 of these cases had normal finger dolorimetry but abnormal forearm hypersensitivity and therefore had CRPS by the Bruehl criteria and not the Atkins.

These finding show that the Bruehl and Atkins criteria are basically concordant. The differences reflect only minor variations in the assessment of pain. Agreement between researchers in the orthopaedic and pain therapy communities will allow improved understanding of the pathophysiology, possible prevention and future methods of managing CRPS.

The technique of bone transport with a conventional Ilizarov external fixator is the current standard means of dealing with segmental bone defects not amenable to bone grafting. Problems with control of the distraction of regenerate bone frequently compromises treatment resulting in secondary deformity. Accurate docking of the defect bone ends is also complex to manage with the Ilizarov apparatus, corrections being possible in only one plane at a time (serial processing).

The Taylor Spatial external fixator (TSF), (Smith and Nephew, Memphis, Tennessee), is a modified Ilizarov fixator with six telescopic struts that are free to rotate at their connection points to the proximal and distal rings. This combination forms a Stewart Gough platform similar to that used in aircraft simulators. By adjusting only strut lengths, and applying Chasles theorem, one ring can be repositioned with respect to the other. Therefore with the aid of computer software, six axis deformities can be corrected simultaneously (parallel processing). We have used this device over the past 2 years in patients with segmental bone defects of the tibia in a stacked mode of application – a three ring construct with six struts between each pair of rings – to allow simultaneous accurately controlled distraction osteogenesis in one segment and independently controlled closure and compression at the docking site.

We present the results of 19 stacked Taylor Spatial frames in 19 patients treated with bone transport in the tibia. The diagnosis was bone resection for infected non union in fourteen, tumour resection in three and acute non infected bone loss secondary to trauma in two. The average age was 34.9 years, (range 10 to 69). Transport ranged from 4 to 12 cm. We used a distraction rate of 0.75mm/day and a comparable compression rate for closure of the defect. At the distraction site, angulation was controlled to within 1degree in any plane and translation to within 1mm in any direction, including length, allowing perfect alignment of the regenerate in all 19 cases. Regenerate quality was uniformly excellent. Superior control of the docking site compared with the Ilizarov fixator was consistently possible and the union rate was 100%. We observed no major complications of treatment. Minor complications included pin and wire infection and breakage all of which were treatable by simple measures with no long term sequelae.

In summary our experience with the stacked TSF for bone transport has shown it to be a highly reliable tool. We have achieved perfect control of regenerate bone in all axes and improved clinical outcomes for these complex problems.

The Taylor Spatial Frame is a new external ring fixation system for correction of multi-planar deformities of the extremities. We report the first 100 consecutive cases treated with this system at the Bristol Limb Reconstruction Unit from November 1999.

The Taylor Spatial Frame incorporates the technology of a virtual hinge and a Stewart Gough Platform. With the use of computer software it is capable of adjustments to within 1 degree and 0.5mm accuracy. Deformities are measured on plain radiographs. Required corrections over any period of time are calculated and a printed prescriptiion of daily adjustments is given to the patients to perform themselves at home.

The following conditions were treated: Non-union (44), malunion (16), Leg length discrepancy (14), limb deformity (13), and acute fractures (13). The aims of frame treatment were non-union treatment (28), bone transport (12), acute fracture healing (12), correction of deformity (28), leg lengthening (15), and arthrodesis (5). Most cases involved the tibia (77) but the frame was also used on the femur (13), knee (3), ankle (4), humerus (2), and forearm (1).

Complete correction of deformity was achieved in all but 7 patients. Union was achieved in 99 cases. All non unions united without bone graft. Mean transport of 46mm and lengthening of 38mm was achieved. 1 arthrodesis failed to unite. All fractures united without any residual deformity. Mean treatment time was 169 days (range 43 to 401). There was 100% compliance with patients performing adjustments themselves. Minor pin site problems were common (34 patients) but only 3 required debridement. Other problems included wire breakage (10), pain (3), peroneal nerve palsy (1) and DVT (1). 15 knees and 11 ankles developed stiffness which resolved.

This study demonstrates the role of the Taylor Spatial Frame as an extremely versatile, accurate and safe new tool at the orthopaedic surgeon’s disposal in limb reconstruction and trauma surgery.

Introduction: Tibial pilon fractures are complex and difficult to manage. Results with extensile approaches, rigid internal fixation and bone grafting remain poor. Percutaneous treatment does not allow anatomic restoration. Current classifications are not helpful. Understanding the anatomy and behaviour of the fracture would allow development of logical algorithms for treatment.

Method: We have analysed plain radiographs and CT scans in a consecutive series of 126 pilon fractures and have defined the fracture anatomy and developed a new classification.

Results: There are six constant articular fragments: anterior, anterolateral (insertion of AITFL), medial, posterior, posterolateral (insertion of PITFL) and die-punch.

Two main fracture families exist depending on the articular fracture pattern. T-type and V/Y-type fractures. A lateral disruption type fracture represents a further important group. An evolution of fracture is evident within the groups.

T-type fractures tend to occur in varus and result from higher energy injuries in younger patients. V/Y-type fractures tend to occur in valgus and result from lower energy injuries in older patients.

Conclusions: We have defined distinct articular fragments, allowing development of safe direct surgical exposures. Stabilisation of the tibial fracture with fine-wire fixators or plates may be employed. The Pathoanatomy could be used in optimal design of such plates. Defining the fracture types gives us a useful and reproducible classification of injury.

Background: Tibial Pilon fractures pose a difþcult management problem. For logical fracture treatment, precise understanding of the 3-D anatomy is essential. Methods: We have studied a consecutive series of 126 pilon fractures. Digitised Xrays and CT scans were analysed using a CAD programme. Results: We have deþned 6 main fragments, at the articular surface. The primary fracture line varied in orientation from coronal (93%) to sagittal (7%), in contrast to the classic description. Observation of the articular fracture patterns revealed ñTñ, ñVñ, ñYñ and pure split fractures with respect to the medial fragment. Fractures, which displace into varus, show a ÒTÒ conþguration, those in valgus a ÒYÒ or ÒVÒ conþguration, (p < 0.001). Fractures with no coronal mal-alignment produce a talo-þbular joint disruption. These different articular patterns require individual techniques for anatomic reduction and þxation.