Introduction: The high prevalence and associated morbidity of the hallux valgus deformity has lead to a myriad treatment options being developed. These range from conservative to operative interventions, including many different forms of osteotomy. The various interventions have met with mixed success, with some operative options suffering a high level of recurrence or patient dissatisfaction. Both outcomes have been shown to correlate to inadequate correction of one or other component of the deformity. High recurrence rates result most frequently from the failure to correct for both the intermetatarsal (IMA) and the distal metatarsal-articular (DMAA) angles, instead focusing on the IMA alone. In most techniques, the use of a two-dimensional osteotomy with a concentric axis of rotation allows only for the correction of one of the involved angles, therefore is not appropriate for the correction of this geometrically complex condition. This most often results in failure to adequately correct the DMAA. The scarf osteotomy is a triplanar osteotomy with the potential to correct both the DMAA and IMA in the same procedure, thereby performing a more anatomical correction.

Hypothesis: Even in experienced hands the accuracy of the correction can be improved, and the limitations of attainable correction identified, with simple calculations based on pre-operative radiographs.

Methods: We generated a formula to calculate the appropriate proximal and distal translations required for a given length of osteotomy to accurately correct the deformities. Two groups, of 20 patients each, were included in the study. One group prior to introduction of the formula and a second group after the introduction of the formula. Pre and post-operative weight bearing radiographs were assessed by blinded observers pre and post-operatively to determine the accuracy of the formula. Groups were compared using the independent samples T-test.

Results: There were no differences between the pre-operative IM and DMA angles between the groups. Post operative DMAA was improved by 6.1 degrees when using the formula (p=0.02). The frequency of post-operative IMA correction to within normal limits improved from 75% to 100% and the average IMA correction was improved by 2.5 degrees (p=0.003). Post operative IM and DMA angles correlated well with the calculated results from the formula. This formula has altered procedure selection in our institution for certain patients with combined large DMA and IM angles due to the easy pre-operative identification of the limits of correction.

Discussion and Conclusion: The formula allows more precise, reproducible correction of both the IMA and DMAA. The formula also clarifies the limits of the scarf osteotomy and therefore improves appropriate patient selection.

Introduction: Complex foot and ankle surgery requires accurate preoperative planning. In the foot corrective osteotomies and lengthening procedures are challenging and can be associated with a range of complications. The aim of planning is to correct only the deformity and prevent extensive surgery on adjacent rays while maintaining biomechanical integrity. Knowledge of foot and ankle morphometry is vital to preoperative planning model. A 3D coordinate system is required for accurate morphological analysis. To conduct meaningful comparison between different subjects the coordinate system between subjects must be constant. Coordinate systems have been defined for other joints, however, there has been no previous description of a coordinate system for 3D analysis in the foot and ankle. We present a coordinate system for 3D data analysis in the foot and ankle and apply this to morphological analysis in the forefoot for preoperative planning.

Methods: CT images of ten anatomically normal feet were segmented in Materialise’s Interactive Medical Image Control System 10.1 (MIMICS) a general purpose segmentation program for grey value images. These files were then imported to a shape analysis program for biomechanics, Arthron. A coordinate frame was defined in a 3 × 3 identity matrix using the inter-malleolar axis and a fibular diaphyseal centroidal axis in the construction. Centroidal vectors were defined in the metatarsals enabling 3D analysis of the forefoot. Correlation of metatarsal length, inter-metatarsal angles, inter-malleolar distance and stature was carried out using Pearson product moment correlation coefficient, r.

Results: The morphology of the forefoot was examined in relation to the medial and lateral columns. The length of the metatarsals had a strong mathematical correlation within each column and between the two columns (0.525 – 0.965). There was also a strong correlation in the length between the lesser metatarsals (0.76 – 0.97) The 3rd metatarsal at the column junction correlated well (−0.583) with the inter-metatarsal angles. There was also a strong correlation between the individual’s stature and the metatarsal length and the inter-malleolar distance (0.60 – 0.89). Specifically in relation to the first metatarsal length there was a good correlation with inter-malleolar (0.75) and suture (0.65).

Discussion: We applied our analysis of the forefoot to the well recognised complication of Hallux Valgus surgery, first metatarsal shortening. This may lead to or exacerbate transfer metatarsalgia due to redistribution of force in the forefoot. Osteotomies of the lesser rays aim to relieve symptoms and re-establish the relationship between metatarsal lengths. However, this does not restore the relationship between metatarsal length, stature and inter-malleolar distance which we have shown to be important. Hurst et al proposed distraction osteogenesis of the first metatarsal to re-establishing length. This would return the normal mathematical relationship, which we have described and seems the most probable way to restore normal foot biomechanics and therefore relieve pain.

Conclusion: We have presented a means defining a coordinate system for 3D data analyses in the foot and ankle. We have shown this coordinate system to be effective in the morphometrical analysis of the forefoot. This analysis shows the importance of a proportional metatarsal length within the forefoot but also in relation to stature and the inter-malleolar distance in preservation of a normal biomechanical environment. This coordinate system can now be used for meaningful comparison of anthropological and morphological data between multiple subjects.

Complex foot and ankle surgery and reconstruction require accurate preoperative planning. In the foot procedures are challenging and can be associated with a range of complications. The aim of planning is to correct only the deformity and prevent extensive surgery. Knowledge of foot and ankle morphometry is vital. For comparison between different subjects the coordinate system must be constant. To the authors knowledge there has been no previous description of a coordinate system for the foot and ankle.

CT images of ten anatomically normal feet were segmented in a general purpose segmentation program for grey value images and imported to a shape analysis program for biomechanics. A coordinate frame was defined in a 3 × 3 identity matrix using the inter-malleolar axis and a fibular diaphyseal centroidal axis in the construction. Centroidal vectors were defined in the metatarsals. Correlation of metatarsal length, inter-metatarsal angles, inter-malleolar distance and height was carried out.

The forefoot was examined in relation to the medial and lateral columns. Metatarsal length had a significant correlation within each column and between the two columns notably in the 3rd (0.525 – 0.965) metatarsal at the columns junction. The 3rd metatarsals also correlated significantly (−0.583) with the inter-metatarsal angles. There was a weak correlation between the 1st 3rd and the 3rd 5th inter-metatarsal angles directly however, each had a large correlation with the 1st 5th inter-metatarsal angle (0.734 – 0.950). There was also a large correlation between the individual’s stature and the metatarsal length and the inter-malleolar distance.

We have presented a means defining a coordinate system for three dimensional analyses in the foot and ankle. This coordinate system can be used for meaningful comparison of data between multiple subjects. We have shown that this coordinate system to be effective in practice in the morphometrical analysis of the normal forefoot.

Graft choices for revision anterior cruciate ligament (ACL) reconstruction and complex ligament reconstructions of the knee are controversial. The aim of our study was to analyze the biomechanical effect of harvesting bone plugs from both the distal and proximal poles of the patella, to simulate a simultaneous harvesting of a Bone – Patellar Tendon – Bone and Quadriceps Tendon – Bone grafts, in a transverse stress environment.

Sixty Bovine Patellae were analysed. They were divided into 4 groups – based on the residual bone bridge (percentage of total length of patella) remaining after bone plug resection. 0 – 10%, 11 – 20%, 21 – 30% and > 30%. All patellae were tested in a modified 4 – point bending environment, to a maximum load of 10,000N, in a customized designed jig. This method simulates the axial bending stress on the patella during knee flexion. All dimensions of the patellae were recorded including Depth of patella at bone resection and wall thickness adjacent to plug resection site.

All patellae with a 0% bone bridge fractured (Ultimate Tensile Strength/UTS) at a mean Tensile Force of 5863N (Range 3140 – 8730N). There was a subgroup of incomplete fractures – extra-articular fractures – which fractured at 6542N (Range 5085 – 9180N). The remaining specimens failed to fracture. Comparing the UTS and the patellar dimensions, using Weibull’s Statistical Analysis we demonstrated that less than 60% bone plug resection carried a very low probability of fracture.

This study demonstrates the safe criteria for bone – tendon graft harvesting from both the proximal and distal poles of the patella. With regards to a normal human patella, a 40% bone – bridge is approximately a 20mm bone – bridge. We conclude that the simultaneous harvesting of Bone – Patellar Tendon – Bone and Quadriceps Tendon – bone grafts from a patella has no significant increase in the fracture risk of the patella.

Hallux rigidus was first described in 1887. Many aetiological factors have been postulated, but none has been supported by scientific evidence. We have examined the static and dynamic imbalances in the first metatarsophalangeal joint which we postulated could be the cause of this condition. We performed a finite-element analysis study on a male subject and calculated a mathematical model of the joint when subjected to both normal and abnormal physiological loads.

The results gave statistically significant evidence for an increase in tension of the plantar fascia as the cause of abnormal stress on the articular cartilage rather than mismatch of the articular surfaces or subclinical muscle contractures. Our study indicated a clinical potential cause of hallux rigidus and challenged the many aetiological theories. It could influence the choice of surgical procedure for the treatment of early grades of hallux rigidus.

Introduction: Percutaneous repairs of Achilles tendon ruptures has gained popularity due the reduced incidence of wound complications, however its use is still limited by the high incidence of sural nerve injuries associated with these repairs. The only technique described to avoid this adverse event is to surgically expose the nerve peri – operatively.

Materials & Methods: In our study we describe and validate a clinical technique to identify the sural nerve. The technique describes flexing the knee to 90°, and supinating the forefoot and inverted the hindfoot. The sural nerve is at its greatest tension in this position and thus the nerve can be palpated along its path. The sural nerve was mapped using this technique both clinically and by US in a cohort of male subjects with intact Achilles tendons.

Results: We demonstrated an excellent correlation between the clinical and US mapping. It also showed excellent inter – observer and intra – observer mapping rates.

Discussion: Sural nerve injuries occur in up to 18% of percutaneous repairs due to the close proximity of the nerve to the tendon along its lateral border. The resultant pain or parasthesia experienced by the patient from sural nerve injuries results in a profound morbidity. This morbidity has lead to the reduced popularity of this procedure. The clinical mapping is a simple easy test, which identifies the nerve along its path and thus the nerve can be avoided during the procedure.

Conclusion: This study demonstrates an accurate and repeatable clinical technique for mapping the sural nerve in conjunction with percutaneous Achilles tendon repairs.

Introduction: The foot is a very complex structure acting as the platform for all gait patterns. At present, little is known about the exact biomechanics of the foot due to the difficulties in modeling all of the components of the foot accurately. This has made it virtually impossible to develop a complete understanding of the aetiology of many diseases of the foot including hallux rigidus. We hypothesize that sagittal plane incongruency of the rotation of the 1^st Metatarsophalangeal Joint (MTPJ), or an increase in the tension of the intrinsic plantar flexors is responsible for the development of hallux rigidus.

Materials & Methods: Ground reaction forces and kinematic data from gait analysis together with anthropometric data from MRI scans of a 24 y.o. female were used to create a Mimics model of the articulation of a normal 1st MTPJ during a gait cycle. The centre of rotation was calculated by triangulating the articular surfaces. Finite element analysis was performed on the model and on similar models with the hypothesized;

joint incongruency,

Results: The results demonstrated a significant increase in the peak stresses, contact areas and stress distributions between the incongruent models compared to the congruent models.

Discussion: To the best of our knowledge this is the most accurate FE model of the 1st MTPJ calculated. Hallux Rigidus is a very common forefoot disorder, with multiple etiologies and treatments advocated. This model demonstrates that an increased tension in the plantar flexors results in a reduced ROM with increased contact stresses on the joint surface.

Conclusion: While it is known Hallux Rigidus has a multi-factorial etiology, the authors feel the above study demonstrates an important inherent etiology.

Background Joint replacement remains the most effective healthcare measure in improving patient health related quality of life (HRQOL) and pain incompatible with normal daily living remains the primary indication for both hip and knee arthroplasty. Quality of life outcome and patient satisfaction after total hip arthroplasty are complex phenomena and many confounding determinants have been identified. Degenerative disease of the hip joint may present with variable patterns of pain referral in the lower limb. However the effect of varied pain referral patterns on patient outcome and satisfaction after total hip arthroplasty has not previously been examined. Methods From 2000 to 2003, 236 eligible patients scheduled to undergo primary total hip arthroplasty were prospectively enrolled. The principle pain referral pattern (as hip, thigh or knee) was identified in all patients. HRQOL was examined using the Harris Hip score (HHS), the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the 36-Item Short-Form Health Survey (SF-36) pre-operatively, 1 year and 2 years postoperatively and with the HHS at 3 months postoperatively. All patients were followed up for a minimum of 2 years. Results The frequency of the pain referral distributions were; hip pain 41%, knee pain 32% and thigh pain 27%. Patients in all groups were comparable preoperatively with respect to age; HHS, and both mean and domain specific WOMAC and SF-36 scores. The mean duration of symptoms was significantly greater in patients with knee pain when compared to the remaining two pain patterns. All patients demonstrated as expected improvements in HHS, SF-36 and WOMAC scores after surgery. At all times postoperatively there were significant differences in mean HHS and mean and domain specific WOMAC and SF-36 scores between patients with hip or thigh pain and those with knee pain (p< 0.001). While notable, differences between hip and thigh pain were not as consistent however. Conclusions Pre-operative pain referral patterns of hip arthritis determine patient outcome and satisfaction after total hip arthroplasty, as measured using validated HRQOL scoring systems. Level of evidence Level I-1 (Prognostic Study-Investigating the Outcome of Disease. Prospective study).

Pathological conditions of the hip joint may present with variable patterns of pain referral in the lower limb. Literature reports suggest that up to 35% of total hip arthroplasties are performed on patients whose primary compliant is obturator nerve referred “knee pain”. However the effect of varied pain patterns on patient outcome and satisfaction has not previously been examined. This prospective study was undertaken to determine the most common referral patterns of hip pain in patients scheduled to undergo primary total hip replacement and to examine whether initial pain referral pattern predicted ultimate patient outcome. Patients were assessed using the Harris Hip score, SF 36 and WOMAC scoring systems measured preoperatively, at 6 months, 1 and 2 years post operatively.

236 patients were identified with isolated single hip joint disease. Patients who demonstrated multi joint disease, and particularly ipsilateral knee pathology were excluded. Forty-five percent of patients with primary hip disease had pain primarily at or about the knee. There was no difference in preoperative demographics, physical function, social function, perceived general health, Harris Hip score (p=0.74), SF 36 (p=0.66) or WOMAC scores (p=0.81) between the pain pattern groups. Operator status and operative techniques were comparable. At 1 and 2 years postoperatively the groin and thigh pain groups were similar in all respects. However at 6 months, 12 months and 2 years, Harris hip scores (p=0.04, p=0.037, p=0.021) and SF 36 scores (p=0.035, p=0.027, p=0.01) were significantly lower in those patients presenting initially with knee pain. Multivariate regression analysis confirmed that no other confounding variables could account for the observed differences between the groups. These results indicate that, using current outcome measures, patients with “knee pain” who undergo total hip arthroplasty, and in whom ipsilateral knee disease has been excluded, have poorer long-term physical and social function and perceived general health. We believe this is the first report of its kind and suggest that patient and surgeon expectations of the results of total hip arthroplasty should be tailored according to the individual initial pain referral pattern.

Arthrodesis of the first metatarsophalangeal joint (MTPJ) is the gold standard treatment of a wide range of pathologies involving the 1st MTPJ. Numerous methods of internal fixation and bone end preparation have been reported to perform this procedure, however there is no universal technique. Therefore in an effort to bring together the best features of the different surgical techniques, a low profile contoured titanium plate (Hallu-S plate), with a compression screw, with a ball and socket bone end preparation were designed. A prospective study was carried out to determine the efficacy of using the Hallu-S plate for 1st MTPJ arthrodesis.

1st MTPJ arthrodesis, using the Hallu-S plate, was carried out in 11 consecutive patients. The procedure was performed in isolation and with other forefoot procedures. Cast immobilization was not used in patients with an isolated 1st MTPJ arthrodesis and the patients were allowed to mobilize (heel walking – full weight bearing) between 2 and 6 weeks postoperatively. The changes in the level of pain and activities of daily living using the AOFAS Hallux score, pre-operatively and at the last assessment, and the time to bone union were assessed.

The mean follow-up time was 10 months (STD 6 months) and there was statistically significant increase in the AOFAS Hallux score. All radiographs at 6 weeks showed bone union and an appropriate degree of dorsiflexion in relation to 1st metatarsal (20–25). The combination of the Hallu-S plate and a ball and socket preparation has both operative and biomechanical advantages over previously described techniques. This combination ensures the biomechanics of the 1st ray are maintained and a better functional result is achieved.

The surgical treatment of chronic Achilles tendon ruptures is essential to restore the normal gait pattern. There are a variety of surgical techniques described, including primary repair, augmentation with tendon transfers, augmentation with aponeurosis flaps and bridging techniques. In recent times augmentation with tendon transfers or aponeurosis flaps are the most commonly performed procedures. Our study examined the biomechanical effect of using the flexor hallicus longus in an augmented chronic Achilles tendon repair on gait pattern and forefoot loading distribution using pedobaragraphical analysis.

We, pedobarographically examined the gait patterns of 10 patients who had undergone augmented chronic Achilles tendon repair using the flexor hallicus longus tendon. The mean age at the time of injury was 59 years of age (range 46–70). The mean follow-up time was 38 months. All patients reported good to excellent results. The mean AOFAS ankle score was 96.25 (range 90–100). There was no statistically significant difference between the loading distributions of the operated foot relative to the contralateral side.

While there is no comparative study examining the outcomes of the varying surgical techniques for chronic Achilles tendon repair, the use of the flexor hallicus longus tendon in augmented chronic Achilles tendon repair has been proven as an effective repair to restore normal function while not compromising the biomechanics of the 1st ray or the loading distribution of the forefoot.

Apert’s syndrome (or acrocephalosyndactyly type 1) is a rare condition characterized by anomalies of the skull (craniosynostosis) in conjunction with complex syndactyly of the hands and feet. There are many studies involving the description and management of hand deformities in Apert’s syndrome. The study of foot anomalies however in children with Apert’s syndrome has been limited to individual case reports and small series. Plain radiographic studies have shown that during childhood, progressive fusion of the bones of the feet occurs. The management of these children’s feet has never been addressed in the literature.

Seven patients with Apert’s syndrome were included in our study. The study group consisted of 2 girls and 5 boys, age range 4–16 years. We performed plain radiography, 3-D computed tomography and paedobarographic studies on all seven children based on our observation that some children with Apert’s had prominent metatarsal heads with symptomatic callosities under the first and second metatarsal heads. Five of the seven children studied demonstrated a specific pattern both on paedobarographic studies and 3D computed tomography of an excessively plantar flexed, fused first and second rays.

A corrective extension osteotomy of the fused first and second rays were then carried out in one patient with an excellent post-operative result. We propose that by early recognition and correction of the pattern of an excessively plantar flexed first and second ray would improve both function and footwear.