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 medical records and radiographs of all patients who underwent
CHAOS for femoral deformity at our institution between 2005 and
2011 were retrospectively reviewed. Records were available for all
55 consecutive procedures undertaken in 49 patients with a mean
age of 35.6 years (10.9 to 75.3) at the time of surgery.Aims
Patients and Methods
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.
This review explores recent advances in fixator design and used in contemporary orthopaedic practice including the management of bone loss, complex deformity and severe isolated limb injury.
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.
Persistent pain is a common cause of disability in patients after fractures of the calcaneum. Amongst the possible causes for post traumatic pain is the development of degenerative osteoarthritis of the posterior facet of the subtalar joint. However there are many other causes of post-traumatic hindfoot pain which require consideration prior to treatment. Knowledge of the patho-anatomy of calcaneal fractures is required to reach an accurate diagnosis. Significant symptoms and disability may be treated by arthrodesis of the subtalar joint. Post-traumatic arthritis in the non-operatively treated calcaneal fracture is however usually associated with deformity of the hindfoot, disordered hindfoot biomechanics, lateral wall fibular impingement and fibular tendon dysfunction. Fractures treated by primary open reduction and fixation should be well aligned but despite anatomic reduction may also develop posterior facet arthritis. Symptoms may also be caused by prominence or impingement of the implant, particularly of locked perimeter plates on the lateral wall. Patients therefore require careful assessment prior to surgery and any operative measures have to address these key features in order to produce a satisfactory clinical result. This lecture will address the potential problems of this type of surgery and key features in the clinical assessment and imaging of these patients. Subtalar arthrodesis in the presence of deformity is technically complex and requires careful planning in order to correct the deformity and to produce a well aligned hindfoot to allow corrected biomechanics without impingement and the fitment of suitable footwear. The surgical techniques and different types of surgery required to adequately manage the posterior facet and deformity will be covered and will include arthroscopically assisted in-situ fusion, the safe approaches for open surgery and techniques to reconstruct the lateral wall, fibular tendon function and osteotomies required to restore calcaneal height and alignment.
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.
Treatment of syndesmotic injuries is a subject of ongoing controversy. Locking plates have been shown to provide both angular and axial stability and therefore could potentially control both shear forces and resist widening of the syndesmosis. The aim of this study is to determine whether a two-hole locking plate has biomechanical advantages over conventional screw stabilisation of the syndesmosis in this pattern of injury. Six pairs of fresh-frozen human cadaver lower legs were prepared to simulate an unstable Maisonneuve fracture. The limbs were then mounted on a servo-hydraulic testing rig and axially loaded to a peak load of 800N for 12000 cycles. Each limb was compared with its pair; one receiving stabilisation of the syndesmosis with two 4.5mm quadricortical cortical screws, the other a two-hole locking plate with 3.2mm locking screws (Smith and Nephew). Each limb was then externally rotated until failure occurred. Failure was defined as fracture of bone or metalwork, syndesmotic widening or axial migration >2mm. Both constructs effectively stabilised the syndesmosis during the cyclical loading within 1mm of movement. However the locking plate group demonstrated superior resistance to torque compared to quadricortical screw fixation (40.6Nm vs 21.2Nm respectively, p value <0.03). A 2 hole locking plate (3.2mm screws) provides significantly greater stability of the syndesmosis to torque when compared with 4.5mm quadricortical fixation.Conclusion
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.
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. Between 1994 –2006, 83 eligible patients were identified. Case notes were reviewed; X-Rays and CT scans were examined and used to rank-order the severity of injury. ‘Musculoskeletal Functional Assessment’ (MFA) and ‘Knee Outcome Survey’ (KOS) questionnaires were completed and axial alignment X-Rays were taken to assess functional and radiological outcome.Introduction
Method
To compare a randomised group of patients undergoing UKA to investigate the advantages of the minimal invasive approach in the early post-operative stage. 100 patients on the waiting list for UKA were recruited into the trial. Patients were prospectively randomised into 2 groups: Group 1 – longitudinal skin incision with dislocation of the patella, Group 2 – the minimally invasive approach. Standard milestones were recorded post-operatively: time to achieve IRQ, independent stair climbing and to discharge. Additionally, patients were scored with the AKSS and Oxford knee questionnaire pre-operatively, at 6 weeks, 6 months and 1 year. No significant differences were found between the 2 groups in the measured parameters.Aims
Results
Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and limb 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 the anatomic and mechanical axes. We have 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 have 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 stylised 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 have examined the utility and reproducibility of the new method using one hundred normal femurs. Θ=81+/− sd 2.5°. As expected, 𝛉 correlated with femoral length (r=0.74). P (expressed as the percentage of the distal from the medial 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 twenty paired normal femora demonstrate similar values for 𝛉 and p on the two sides. We have employed this technique in a variety of distal femoral deformities, including vitamin D resistant rickets, growth arrest, fibula hemimelia, post-traumatic deformity and Ellis-van Creveld syndrome. We find the system universally applicable and reliable.
A series of 49 pilon fractures in a tertiary referral centre treated definitively with open reduction and internal fixation have been assessed examining the complications associated with such injuries. A retrospective analysis of casenotes, radiographs and computerised tomographs over a seven year period from 1999–2006 was performed. Infection was the most common post operative problem. There were 7 cases of superficial infection. There was a single case of deep infection requiring intravenous antibiotics and removal of metalwork. Other notable complications were those of secondary osteoarthritis (three cases) and malunion (one case). The key finding of this paper is the 2% incidence of deep infection following the direct operative approach to these fractures. The traditional operative approach to such injuries (initially advocated by Ruedi and All-gower) consisted of extensive soft tissue dissection to gain access to the distal tibia. Our preferred method is to gain access to via the “direct approach” which involves direct access to the fracture site with minimal disturbance of the soft tissue envelope. We therefore believe open reduction and internal fixation of pilon fractures via the direct approach to be an excellent technique in the treatment of such injuries.
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.
There is a relative risk of 3.0 of dislocation in cups with ≤15 degrees of anteversion compared with >
15 degrees of anteversion. This difference in dislocation is statistically significant (p<
0.01). Increased femoral offset compared with the normal contralateral hip is statistically significantly associated with an increased risk of dislocation (p=0.03). Change in leg length is not associated with dislocation risk.
The increase in femoral offset in the prosthetic hip compared with the normal contralateral hip and its association with dislocation may be due to intraoperative attempts to compensate for an unstable hip by increasing offset. These results indicate that a surgeon should be cautious when increasing femoral offset alone to try and compensate for a potentially unstable hip. Other factors, for example acetabular version should be addressed, with readjustment of cup position intra-operatively if required.
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.
No significant differences were found between the 2 groups in the measured parameters.
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.
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.
In a series of 126 consecutive pilon fractures, we have described anatomically explicable fragments. Fracture lines describing these fragments have revealed ten types of pilon fracture which belong to two families, sagittal and coronal. The type of fracture is dictated by the energy of injury, the direction of the force of injury and the age of the patient.
Tibial Pilon fractures pose a difficult management problem. For logical fracture treatment, precise understanding of the 3-D anatomy is essential. We have studied a consecutive series of 126 pilon fractures. Digitised X-rays and CT scans were analysed using a CAD programme. We have defined six main fragments at the articular surface, their relative frequency and their proportion: Anterior (A) present in 89%, 28% of area. Posterior (P) present in 89%, 40% of area. Medial (M) present in 74%, 29% of area. Anterolateral (AL) present in 34%, 8% of area. Posterolateral (PL) present in 21%, 9% of area. Die-punch (DP) present in 43%, 4% of area. The primary fracture line varied in orientation from coronal (93%) to sagittal (7%), in contrast to the classic description. Within those cases where the primary fracture line was coronal we found hitherto undescribed variations in the articular pattern, there being ‘T’, ‘V’, ‘Y’ and pure split fractures with respect to the medial fragment. Fractures which displace into varus show a “T” configuration, those in valgus a “Y” or “V” configuration, (p <
0.001). Fractures with no coronal mal-alignment produce a talo-fibular joint disruption. Once recognised these different articular patterns require individual techniques for anatomic reduction and fixation.
Optimal treatment of articular fractures is open anatomic reduction and rigid internal fixation. In pilon fractures, this has been associated with unacceptable complication rates. The cutaneous blood supply of the anterior aspect of the distal tibia is from short direct radial vessels which themselves arise from arteries closely adherent to the deep fascia. On the anteromedial aspect of the leg the deep fascia is fused with the periosteum. We hypothesise that shearing associated with displaced fractures divide these short radial vessels, rendering the skin critically ischaemic. Standard extensile approaches lead to further devitalisation and wound breakdown. It follows that a direct approach onto the fracture line should do minimal extra damage to the blood supply. Of 97 pilon fractures, 53 have required an open reduction. Median age 43, 39 male. Mechanism of Injury: fall-41, RTA-10, other-two. 19% open (60% IIIB). Time to surgery nine days. A longitudinal incision with full thickness flaps is based directly over the fracture, not necessarily following internervous planes. Anatomic reduction was achieved in all cases. There was only one complication of wound breakdown (2%). This technique affords a safe and reliable approach to the fractured articular surface. Lack of wound breakdown may rely on the use of fine-wire circular frame external fixators for stabilisation of the proximal fracture. Whether this approach will allow plate fixation, remains to be seen.
Os calcis fracture patterns in ten children (mean age 12. 8) with eleven fractures were classified using plain films and CT scans and found to be similar to those in adults. All except two of the fractures (which were not significantly displaced) were treated with open reduction and internal fixation. In all cases it was possible to achieve anatomic reduction and rigid internal fixation. Eight patients had ‘excellent’ long-term clinical results. One patient with a court case pending scored ‘good’, and one patient with an ipsilateral talar neck fracture scored ‘fair’. This patient had mildly limited ankle movement; all others had full ankle movement. Six had full subtalar movement, in 2 it was mildly limited and in three it was moderately limited (50–80%). There was no evidence of abnormality of the physes on follow up x-rays. We conclude that operative treatment of these fractures yields optimal results.
Much has been written about the use of different treatment modalities in the management of distal femoral fractures. These articles, however, do not include the use of the Ilizarov frame amongst the modalities described. We have experience in the use of the Ilizarov frame in the definitive treatment of both non-union and acute fracture of the distal femur. We report our experience and conclusions. The medical records of all patients who had undergone Ilizarov frame management for acute distal femoral fracture or established non-union were reviewed. Demographic data, the complications of surgery, duration of treatment with the frame and recorded outcome were noted. All patients were further assessed (either in clinic or by telephone interview) and completed a Short Musculoskeletal Function Assessment Form. We have treated 17 patients (11 male, 6 female), 8 were acute compound fractures and 9 non union/infected ORIF’s of the distal femur. All patients have had their frames removed and were united. The mean age at the time of frame application was 36.6 years (range 18.7–58.7). The mean time from frame application to union was 230 days (range 81–514). Noted major complications included refracture in two patients, persisting infection in one, chronic regional pain syndrome in one and limited range of movement in all (mean knee movement of 62 ranging from 2–100). Two patients have had above knee amputations and a further patient has requested above knee amputation. Short Musculoskeletal Function Assessment Form shows significant dysfunction with a mean score of 42.9/100 (range 8.15–82.85). Treatment of distal femoral fractures is notoriously difficult. Other treatment modalities (i.e. Intra Medullary (IM) supracondylar nail) offer many advantages over Ilizarov frame use.