3D accurate measurements of the skeletal structures of the foot, in physiological and impaired subjects, are now possible using Cone-Beam CT (CBCT) under real-world loading conditions. In detail, this feature allows a more realistic representation of the relative bone-bone interactions of the foot as they occur under patient-specific body weight conditions. In this context, varus/valgus of the hindfoot under altered conditions or the thinning of plantar tissues that occurs with advancing age are among the most complex and interesting to represent, and numerous measurement proposals have been proposed. This study aims to analyze and compare these measurements from CBCT in weight-bearing scans in a clinical population. Sixteen feet of diabetic patients and ten feet with severe adult flatfoot acquired before/after corrective surgery underwent CBCT scans (Carestream, USA) while standing on the leg of interest. Corresponding 3D shapes of each bone of the shank and hindfoot were reconstructed (Materialise, Belgium). Six different techniques found in the literature were used to calculate the varus/valgus deformity, i.e., the inclination of the hindfoot in the frontal plane of the shank, and the distance between the ground and the metatarsal heads was calculated along with different solutions for the identification of possible calcifications. Starting with an accurate 3D reconstruction of the skeletal structures of the foot, a wide range of measurements representing the same angle of hindfoot alignment were found, some of them very different from each other. Interesting correlations were found between metatarsal height and subject age, significant in diabetic feet for the fourth and fifth metatarsal bones. Finally, CBCT allows 3D assessment of foot deformities under loaded conditions. The observed traditional measurement differences and new measurement solutions suggest that clinicians should consider carefully the anatomical and functional concepts underlying measurement techniques when drawing clinical and surgical conclusions

Abstract. Background. Tibiotalocalcaneal (TTC) fusion is indicated for severe arthritis, failed ankle arthroplasty, avascular necrosis of talus and as a salvage after failed ankle fixation. Patients in our study had complex deformities with 25 ankles having valgus deformities (range 50–8 degrees mean 27 degrees). 12 had varus deformities (range 50–10 degrees mean 26 degrees) 5 ankles an accurate measurement was not possible on retrospective images. 10 out of 42 procedures were done after failed previous surgeries and 8 out of 42 had talus AVN. Methods. Retrospective case series of patients with hindfoot nails performed in our centre identified using NHS codes. Total of 41 patients with 42 nails identified with mean age of 64 years. Time to union noted from X-rays and any complications noted from the follow-up letters. Patients contacted via telephone to complete MOXFQ and VAS scores and asked if they would recommend the procedure to patients suffering similar conditions. 17 patients unable to fill scores (5 deceased, 4 nails removed, 2 cognitive impairment and 6 uncontactable). Results. In our cohort 33/38 of hindfoot nails achieved both subtalar and ankle fusion in a mean time of 7 months. 25 patients with 26 nails had mean follow up with post op scores of 4 years. Their Mean MOXFQ scores were (Pain: 12.8 Walking: 12 Social: 8) and visual analogue pain score was 3. 85% of patients wound recommend this surgery for a similar condition. 20 complications with 15 requiring surgery(5 screw removals, 1 percutaneous drilling, 1 fusion site injection, 8 nail revisions). Conclusion. In our experience hindfoot nail TTC fusion reliably improves the function of patients with severe symptoms in a variety of pathophysiological conditions and complex deformities. Most of our patients would recommend this procedure. There is a lack of studies with long-term follow-up

Background. Plate fixation is one of several options available to surgeons for the management of pediatric femur fractures. Recent literature reports distal femoral valgus can be a complication following lateral plate fixation of femur fractures. We report on a case of extreme distal femoral valgus deformity and a lateral dislocation of the patella four years after having plate fixation of a left distal femoral fracture. Method. A single case was anonymised and retrospectively reviewed through examination of clinical and radiographic data. Results. A 15 year old male presented with 35 degree femoral valgus deformity, one inch leg length discrepancy, painful retained hardware and a lateral dislocation of the patella four years after undergoing lateral plate fixation of a left distal femur fracture. The fracture site healed after plate insertion, but later the patient reported worsening in alignment of lower extremity and complained of pain in the limb. Antero-posterior and lateral radiographs of the femur revealed 35 degrees of left distal femoral valgus. The previous femoral plate migrated proximally and was encased in bone. Due to plate migration, screws that were originally in the distal femoral metaphysis were protruding through the femoral shaft into soft tissues of the medial thigh. Successful treatment involved removal of prominent distal screws and use of a Taylor Spatial external fixator frame to correct the deformity. Lateral soft tissue release was performed to allow patellar relocation. At 12 weeks follow up leg alignment was restored, pain resolved and the patient was mobilising. Conclusion. Femoral valgus is a possible complication of lateral plate fixation in up to 30% of pediatric distal femur fractures. With this patient's combination of deformities as an example, we suggest early hardware removal after fracture union, preventing deformities developing. If plate removal is not chosen, then continued close monitoring of the patient is necessary until skeletal maturity. Level of Evidence. Type 4 (case report)

Osteonecrosis is a potentially devastating condition with poorly defined pathogenesis that can affect several anatomical areas with or without a previous traumatic insult. Post traumatic osteonecrosis (PON) in the foot and ankle has been commonly described in the talus and navicular but rarely in the distal tibia. PON of the distal tibia is a rarely reported and infrequent complication of fracture dislocations of the ankle. Its scarcity can lead to misdiagnosis and inappropriate management due to a lack of clinical knowledge or suspicion with resultant severe functional compromise. We aim to highlight the clinical and radiological features of PON of the distal tibia and report the findings in a series of four patients following a fracture dislocation of the ankle. Three patients sustained a SER4 fracture dislocation and one patient sustained a PER4 fracture dislocation in keeping with standard patterns of injury seen in most trauma units. In each case, PON of the distal tibia presented with progressive anterolateral tibial plafond collapse and valgus deformity of the ankle. The radiological features previously reported in the literature are based on plain film x-ray, CT and MRI but no description of SPECT-CT findings. One of the patients in the series underwent SPECT-CT following clinical suspicion of PON and thus we describe the findings not previously reported. Our objective is to highlight this rare condition as a potential cause for ongoing pain following fracture dislocation of the ankle as well as advocating the use of SPECT/CT as a useful imaging modality to aid in the diagnosis

An adult acquired flatfoot deformity (AAFD) is a complex 3D deformity. Surgical correction consists of a medial calcaneal osteotomy (MCO) but shows limitations due to the current 2D assessment. Therefore, the aim is to determine the influence of an MCO on the longitudinal foot arch assessed by 2D and 3D weightbearing CT (WBCT). Seventeen patients with a mean age of 44,5 years (range 18–66 yrs) were retrospectively included. MCO was indicated in a stage II AAFD (N=15) and a post-traumatic valgus deformity (N=2). Pre- and post-operative imaging was obtained from a WBCT. The height of the longitudinal foot arch was measured as the distance from the navicular tuberositas to the floor (Navicular Height, NH) on 2D CT images (NH. 2D. ) and computed on 3D CT data (NH. 3D. ). Additionally, 3D assessment could compute the degree of exorotation (α) of the navicular bone towards the vertical axis. The mean pre-operative NH. 2D. and NH. 3D. were respectively 29.57mm ± 7.59 and 28.34mm ± 6.51. These showed to be statistically different from the mean post-operative NH. 2D. and NH. 3D. , respectively 31.62mm ± 6.69 and 31.67mm ± 6.47 (p < 0,001). A statistical difference was also found when comparing the mean degree of exorotation in pre- and post-operative, respectively: α. pre. =14.08° ± 4,92 and the α. post. =19,88° ± 3.50 (p < 0,001). This study demonstrates a significant correction of the longitudinal foot arch after a MCO. The novelty is attributed to the accurate degree of rotation assessment using WBCT. This information could be assistive to optimise a pre-operative planning

Knee arthroplasty with a rotating hinge knee (RHK) prosthesis has become an important clinical treatment option for knee revisions and primary patients with severe varus or valgus deformities and instable ligaments. The rotational axle constraints the anterior-posterior shear and varus-valgus moments, but currently used polyethylene bushings may fail in the mid-term due to insufficient creep and wear resistance of the material. Due to that carbon-fibre-reinforced (CFR) PEEK as an alternativ bushing material with enhanced creep, wear and fatigue behaviour has been introduced in a RHK design [Grupp 2011, Giurea 2014]. The objective of our study was to compare results from the pre-clinical biotribological characterisation to ex vivo findings on a series of retrieved implants. In vitro wear simulation according to ISO 14243-1 was performed on rotating hinge knee devices (EnduRo® Aesculap, Germany) made out of cobalt-chromium and of a ZrN multi-layer ceramic coating for 5 million cycles. The mobile gliding surfaces were made out of polyethylene (GUR 1020, β-irradiated 30 ± 2 kGy). For the bushings of the rotational and flexion axles and the flanges a new bearing material based on CFR-PEEK with 30% PAN fiber content was used. Analysis of 12 retrieved EnduRo. ®. RHK systems in cobalt-chromium and ZrN multi-layer in regard to. -. loosening torques in comparison with initial fastening torques. -. Optical, DSLR camera and stereo light microscope analysis. -. distinction between different wear modes and classification with a modified HOOD-score. -. SEM & EDX of representative samples. -. surface roughness and depth profilometry. with a focus on the four CFR-PEEK components integrated in the EnduRo. ®. RHK design. For the rotating hinge knee design with flexion bushing and flanges out of CFR-PEEK the volumetric wear rates were 2.3 ± 0.48 mm. 3. /million cycles (cobalt-chromium) and 0.21 ± 0.02 mm. 3. /million cycles (ZrN multi-layer), a 10.9-fold reduction (p = 0.0016). The UHMWPE and CFR-PEEK particles were comparable in size and morphology and predominantly in submicron size [5]. The biological response to representative sub-micron sized CFR-PEEK particles has been demonstrated in vivo based on the leucoyte-endothelian-cell interactions in the synovia of a murine intra-articular knee model by Utzschneider 2010. Schwiesau 2013 extracted the frequency of daily activities in hip and knee replacement patients from literature and estimated an average of 1.76 million gait cycles per year. Thus, the 5 million cycles of in vitro wear testing reflect a mean in vivo service life of 2.9 years, which fits to the time in vivo of 12–60 months of the retrieved RHK devices. The in vitro surface articulation pattern of the wear simulation tests are comparable to findings on retrieved CFR-PEEK components for both types of articulations – cobalt-chromium and ZrN multi-layer coating. For the rotating hinge knee design the findings on retrieved implants demonstrate the high suitability of CFR-PEEK as a biomaterial for highly loaded bearings, such as RHK bushings and flanges in articulation to cobalt-chromium and to a ZrN multi-layer coating

The aim of this study is to assess the discrepancy between weight bearing long leg radiographs and supine MRI alignment. There is currently increasing interest in the use of MRI to assess knee alignment and develop custom made cutting blocks utilising this data. However in almost all units MRI scans are performed supine and it is recognised that knee alignment can alter with weight bearing. 46 patients underwent MRI scans as pre-operative planning for Biomet signature total knee replacement and the measure of varus or valgus deformity on MRI was obtained from the plan produced by Biomet Signature software system. 41 of these patients had long leg weight bearing radiographs performed. 37 of these radiographs were amenable to measuring the knee alignment on the picture archiving and communication system (PACS). These measurements were performed by two assessors and inter-observer reliability was satisfactory. There was a significant difference between the alignment as measured on supine MRI compared with weight bearing long leg films. In knee arthroplasty one of the aims is to correct the biomechanical axis of the knee and one of the appeals of custom made cutting blocks is that this can be achieved more easily. However it is important to realise that alignment is not a static value and thus correcting supine alignment may not necessarily result in correction of weight bearing alignment

Hindfoot disorders are complex 3D deformities. Current literature has assessed their influence on the full leg alignment, but the superposition of the hindfoot on plain radiographs resulted in different measurement errors. Therefore, the aim of this study is to assess the hindfoot alignment on Weight-Bearing CT (WBCT) and its influence on the radiographic Hip-Knee-Ankle (HKA) angle. A retrospective analysis was performed on a study population of 109 patients (mean age of 53 years ± 14,49) with a varus or valgus hindfoot deformity. The hindfoot angle (HA) was measured on the WBCT while the HKA angle, and the anatomical tibia axis angle towards the vertical (TA. X. ) were analysed on the Full Leg radiographs. The mean HA in the valgus hindfoot group was 9,19°±7.94, in the varus hindfoot group −7,29°±6.09. The mean TA. X. was 3,32°±2.17 in the group with a valgus hindfoot and 1,89°±2.63 in the group with a varus hindfoot, which showed to be statistically different (p<0.05). The mean HKA Angle was −1,35°±2.73 in the valgus hindfoot group and 0,4°±2.89 in the varus hindfoot group, which showed to be statistically different (p<0.05). This study demonstrates a higher varus in both the HKA and TA. X. in valgus hindfoot and a higher tibia valgus in varus hindfoot. This contradicts the previous assumption that a varus hindfoot is associated with a varus knee or vice versa. In clinical practice, these findings contribute to a better understanding of deformity corrections of both the hindfoot and the knee

Summary Statement. We present a simple and useful geometrical equation system to carry out the pre-operative planning and intra-operative assessments for total knee arthroplasty. These methods are extremely helpful in severely deformed lower limbs. Introduction. Total knee arthroplasty is a highly successful surgery for most of the patients with knee osteoarthritis. With commercial instruments and jigs, most surgeons can correct the deformity and provided satisfactory results. However, in cases with severe extra-articular deformity, the instruments may mislead surgeons in making judgment of the true mechanical axis. We developed a geometrical equation system for pre-operative planning and intra-operative measurement to perform correct bony cuts and achieve good post-operative axis. Patients & Methods. From 2008 to 2012, twenty-four patients with severe extra-articular deformities of low limbs underwent total knee arthroplasties for osteoarthritis. The deformities included malunion of femoral or tibial shafts with angulation, non-union of femoral supracondylar fractures, failed high tibia osteotomies, severe bowing of femurs, and other post-traumatic sequelae. The intra-medullary or extra-medullary guide devices were not possible to provide correct axis in these cases. For pre-operative planning, we analyzed the deformities on triple-film scanography and standing anterior-posterior and lateral X-ray films. The angles needed to be corrected in coronal and sagittal planes were measured. A geometrical equation system was applied to calculate the thickness of the proximal tibia cut and distal femoral cut. If the flexion contracture was presented, the degree of necessary elevation of joint line was also calculated. Intra-operatively, the degree of rotation of anterior and posterior femoral cuts was assessed after proximal tibial and distal femoral cuts. The sizes of prosthesis were judged according to the balance between flexion and extension gaps. A 3-in-1 jig was used for chamfering of the femur. After fine-tuning of bony cuts and balancing of soft tissue, the prostheses were cemented. The conventional intra-medullary and extra-medullary guiding devices were not used during the whole procedure. Results. All of the patients achieved satisfactory results in the aspect of pain relief and functional outcomes. All patients had good post-operative axis in coronal plane (varus or valgus deformity < 3 degrees). Twenty-two patients (92%) achieved good sagittal alignments (deformity < 3 degrees). The results were compatible with those in the patient population without those severe deformities. There was no major complication among these patients. Discussion/Conclusion. In this series, we present a simple and useful geometrical equation system to carry out the pre-operative planning and intra-operative assessments for total knee arthroplasty. These methods are extremely helpful in severely deformed lower limbs. Optimal post-operative alignments were achieved in this series and no major complication was found

Total knee arthroplasty (TKA) is a common orthopaedic procedure. Traditionally the surgeon, based on experience, releases the medial structures in knees with varus deformity and lateral structures in knees with valgus deformity until subjectively they feel that they have achieved the intended alignment. The hypothesis for this study was that deformed knees do not routinely require releases to achieve an aligned lower limb in TKA. A single surgeon consecutive cohort of 74 patients undergoing computer navigated TKA was examined. The mechanical axes were taken as the references for distal femoral and proximal tibial cuts. The trans-epicondylar axis was taken as the reference for frontal femoral and posterior condylar cuts. A soft tissue release was undertaken after the bony cuts had been made if the mechanical femoro-tibial (MFT) angle in extension did not come to within 2° of neutral as shown by computer readings. The post-operative alignment was recorded on the navigation system and also analysed with hip-knee-ankle (HKA) radiographs. The range of pre-operative deformities on HKA radiographs was 15° varus to 27° valgus with a mean of 5° varus (SD 7.4°). Only two patients required a medial release. None of the patients required a lateral release. The post implant navigation value was within 2° of neutral in all cases. Post-operative HKA radiographs was available for 71 patients. The mean MFT angle from radiographs was 0.1° valgus (SD 2.1°). The range was from 6° varus to 7° valgus but only six patients (8.5%) were outside the ±3° range. The kinematic analysis also showed it to be within 2 degrees of neutral throughout the flexion making sure it is well balanced in 88% cases. This series has shown that over 90% of patients had limbs aligned appropriately without the need for routine soft tissue releases. The use of computer assisted bone cuts leads to a low level of collateral release in TKA

INTRODUCTION. Intramedullary nail fixation has been used for successful treatment of long bone fracture such as humerus, tibia and femur. We look at the experience of our trauma unit in treating long bone fracture using the AO approved Expert femoral/tibial nail and proximal femoral nail antirotation (PFNA). We look at the union and complication rates in patients treated with AO approved nailing system for pertrochanteric, femoral and tibial shaft fracture. METHODS. We carried out retrospective case notes review of patients that underwent femoral and tibial nailing during the period of study- October 2007 to August 2009. All patients were treated using the AO approved nailing system. We identified all trauma patients that underwent femoral and tibial nailing through the trauma register. Further information was then obtained by going through medical notes and reviewing all followed-up X-rays stored within the online radiology system. RESULTS. 149 patients, 85 male and 64 female were included into the study. 150 procedures were carried out during period of study as 1 patient underwent conversion of lateral entry femoral nail to PFNA due to refracture. Patients' age ranged from 14-96 with mean of 55. 140 patients had isolated long bone fracture (either femur or tibia) compared to 9 patients with multiple bone fractures. Our unit performed 64 Expert tibial nail, 36 PFNA, 31 Expert lateral entry femoral nail and 19 Expert retrograde femoral nail during period of study. 13 patients treated with intramedullary nail sustained open fracture, 9 of them were compound tibial fracture compared to 4 compound femoral fractures. All patients were followed-up between 2 to 24 months or until death. 9 out of 17 patients that died in this study had diagnosis of tumour. Complication rates were 17% for Expert tibial nail (1 patient with valgus deformity, peroneal nerve palsy and delayed union, 3 with delayed union, 4 with broken locking screw, 2 with wound infection and 1 with abscess over wound site), 4% for lateral/retrograde femoral nail (1 each for pulmonary embolism and broken locking screw) and 4% for PFNA (1 each for delayed union and deep vein thrombosis). The overall complication rates were 10% from this study. DISCUSSION & CONCLUSIONS. We conclude that the AO approved nailing system used for treating pertrochanteric, femoral and tibial fractures were effective with high union rate. The overall complication rates were 10% from this study. Complication rates for tibial nail were as high as 17% compared to 4% for femoral nail or PFNA. The complication rates for PFNA in our study were lower compared to 29% in PFN that was reported in one literature

Objectives

The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method.

Rebound growth after hemiepiphysiodesis may be a normal event, but little is known about its causes, incidence or factors related to its intensity. The aim of this study was to evaluate rebound growth under controlled experimental conditions.

A total of 22 six-week-old rabbits underwent a medial proximal tibial hemiepiphysiodesis using a two-hole plate and screws. Temporal growth plate arrest was maintained for three weeks, and animals were killed at intervals ranging between three days and three weeks after removal of the device. The radiological angulation of the proximal tibia was studied at weekly intervals during and after hemiepiphysiodesis. A histological study of the retrieved proximal physis of the tibia was performed.

The mean angulation achieved at three weeks was 34.7° (standard deviation (sd) 3.4), and this remained unchanged for the study period of up to two weeks. By three weeks after removal of the implant the mean angulation had dropped to 28.2° (sd 1.8) (p < 0.001). Histologically, widening of the medial side was noted during the first two weeks. By three weeks this widening had substantially disappeared and the normal columnar structure was virtually re-established.

In our rabbit model, rebound was an event of variable incidence and intensity and, when present, did not appear immediately after restoration of growth, but took some time to appear.

Cite this article: Bone Joint J 2015;97-B:862–8.

The understanding of rotational alignment of the distal femur is essential in total knee replacement to ensure that there is correct placement of the femoral component. Many reference axes have been described, but there is still disagreement about their value and mutual angular relationship. Our aim was to validate a geometrically-defined reference axis against which the surface-derived axes could be compared in the axial plane. A total of 12 cadaver specimens underwent CT after rigid fixation of optical tracking devices to the femur and the tibia. Three-dimensional reconstructions were made to determine the anatomical surface points and geometrical references. The spatial relationships between the femur and tibia in full extension and in 90° of flexion were examined by an optical infrared tracking system.

After co-ordinate transformation of the described anatomical points and geometrical references, the projection of the relevant axes in the axial plane of the femur were mathematically achieved. Inter- and intra-observer variability in the three-dimensional CT reconstructions revealed angular errors ranging from 0.16° to 1.15° for all axes except for the trochlear axis which had an interobserver error of 2°. With the knees in full extension, the femoral transverse axis, connecting the centres of the best matching spheres of the femoral condyles, almost coincided with the tibial transverse axis (mean difference −0.8°, sd 2.05). At 90° of flexion, this femoral transverse axis was orthogonal to the tibial mechanical axis (mean difference −0.77°, sd 4.08). Of all the surface-derived axes, the surgical transepicondylar axis had the closest relationship to the femoral transverse axis after projection on to the axial plane of the femur (mean difference 0.21°, sd 1.77). The posterior condylar line was the most consistent axis (range −2.96° to −0.28°, sd 0.77) and the trochlear anteroposterior axis the least consistent axis (range −10.62° to +11.67°, sd 6.12). The orientation of both the posterior condylar line and the trochlear anteroposterior axis (p = 0.001) showed a trend towards internal rotation with valgus coronal alignment.

Recently, femoroacetabular impingement has been recognised as a cause of early osteoarthritis. There are two mechanisms of impingement: 1) cam impingement caused by a non-spherical head and 2) pincer impingement caused by excessive acetabular cover. We hypothesised that both mechanisms result in different patterns of articular damage. Of 302 analysed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused damage to the anterosuperior acetabular cartilage with separation between the labrum and cartilage. During flexion, the cartilage was sheared off the bone by the non-spherical femoral head while the labrum remained untouched. In pincer impingement, the cartilage damage was located circumferentially and included only a narrow strip. During movement the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification.

Both cam and pincer impingement lead to osteoarthritis of the hip. Labral damage indicates ongoing impingement and rarely occurs alone.