Abstract. Background. Little scientific evidence is available regarding the effect of knee joint line obliquity (JLO). Methods. 10 fresh-frozen human cadaveric knees were axially loaded to 1500 N in a materials testing machine with the joint line tilted 0, 4, 8, and 12 degrees varus and valgus, at 0, and 20 degrees of knee flexion. The mechanical compression axis was aligned to the centre of the tibial plateau. Contact pressures / areas were recorded by sensors inserted between the tibia and femur below the menisci. Changes in relative femoral and tibial position in the coronal plane were obtained by an optical tracking system. Results. medial and lateral JLO caused significant tibiofemoral subluxation and pressure distribution changes. Medial (varus) JLO caused the femur to sublux medially down the coronal slope of the tibial plateau, and vice versa for lateral (valgus) downslopes (P=0.01). Areas of peak pressure moved 12 mm and 8 mm across the medial and lateral condyles, onto the ‘downhill’ meniscus and the ‘uphill’ tibial spine. Changes in JLO had only small effects on maximum contact pressures. Conclusion. A change of JLO during load bearing caused significant mediolateral tibiofemoral subluxation. The femur slid down the slope of the tibial plateau to abut the tibial eminence and also to rest on the downhill meniscus. Clinical Relevance. These results provide important information for understanding the consequences of creating coronal JLO and for clinical practice in terms of osteotomy planning regarding the effect on JLO

Introduction: Patellofemoral joint subluxation is associated with pain and dysfunction. The causes of patel-lofemoral subluxation are poorly understood and multi-factorial, arising from abnormalities of both bone and soft tissues. This study aims to identify which anatomical variables assessed on Magnetic Resonance (MR) images are most relevant to patellofemoral subluxation. Method: A retrospective analysis of MR studies of 60 patients with suspected patellofemoral subluxation was performed. All patients were graded for the severity/ magnitude of radiological subluxation using a dynamic MR scan (Grade 0 [nil] to Grade 3 [subluxed]. The patient scans were assessed using a range of anatomical variables, these included:. Patella alta,. Patella type (Wiberg classification),. Trochlea sulcus angles for bone and cartilage,. The shortest horizontal distance between the most distal part of the vastus medialis obliquis (VMO) muscle to the supra-medial aspect of the patella,. Trochlea and patella cartilage thickness (maximum depth),. The horizontal distance between the tibial tubercle and the midpoint of the femoral trochlea (TTD),. Patella Engagement – represented as the percentage of the patella height that is captured in the trochlea groove when the knee is in full extension,. A Discriminant Analysis test for multi-variant analysis was applied to establish the relationship between each bony/soft tissue anatomical variable and the severity/magnitude of patellofemoral subluxation. Results: The distance of the VMO from the patella (p < 0.001), TTD (p < 0.001) and Patella Engagement (p < 0.001) showed highly significant relationships with patellofemoral subluxation. Conclusions: The following three anatomical variables are associated with patellofemoral subluxation: the distance of the VMO muscle from the patella, TTD and Patella Engagement. This is the first study to establish that patella engagement is related to PFJ subluxation showing that the lower the percentage engagement of the patella in the trochlea, the greater the severity/magnitude of patellofemoral subluxation. The finding provides greater insight into the aetiology and understanding of the mechanism of symptomatic PFJ subluxation

Metal-on-Metal devices generate significantly lower volumetric wear than conventional total hip replacements. However, clinically some patients may suffer some form of laxity in their joints leading to subluxation of the joint, which in turn may cause edge loading of an implant thereby increasing the chances of failure due to higher than expected wear. In this study, the effect of subluxation on MoM implant wear was investigated on a hip joint simulator. Materials & Methods. Two groups of 44 mm MoM devices were tested, n=3 in each group. The devices were subjected to 1 and 2 mm of subluxation. The flexion/extension was 30° and 15° respectively, internal/external rotation was ±10°, and cup inclination was 35°. The force was Paul type stance phase loading with a maximum load of 3 kN, with ISO swing phase load of 0.3 kN, run at 1 Hz. The test was carried out on a ProSim deep flexion & subluxation hip wear simulator (SimSol, UK). Rather than separating the head and the cup (microseparation), or reducing the swing phase load, this simulator is equipped with a novel mechanism to achieve translation of the head, while subjecting the devices to subluxation. During the swing phase, a controlled lateral force necessary for the translation of the head is applied by a cam mechanism, head retraction will then take place on heel strike. The lubricant used was new born calf serum with 0.2 wt. % sodium azide concentration diluted with de-ionised water to achieve average protein concentration of 20 g/l. Lubricant was changed every 250k cycles. Gravimetric wear measurements have been taken at 0.25 & 0.5 Mc stages. Results. Tests conducted with 1mm (Group 1) and 2mm (Group 2) subluxation significantly increased volumetric wear compared to standard hip simulator tests [1]. At 0.5 million cycles, group 1 and 2 produced an average volume loss of 4.38±0.98 mm. 3. (95% CL) and 7.07±1.64 mm. 3. (95% CL) respectively. Discussion/conclusion. Well positioned and well-fixed hip implants perform well in vitro and in vivo; however optimal performance a device can be affected by a number of factors from design, technical factors, patient factors, surgical technique to position of the device in vivo. The study presents test results of a hip joint simulator with a subluxation mechanism to simulate clinically relevant subluxation during the swing phase of a gait cycle under the ISO swing phase load of 0.3kN, with differing levels of luxation. Increasing the level of subluxation in turn increased volumetric wear due to greater head contact at the superior rim of the cup. Further tests will be conducted with high cup inclination angles (>45°) and subluxation to determine the effect upon wear. Tests which can simulate the (ideal and adverse) conditions clinically can help to improve the design and understanding of implant behaviour in vivo

INTRODUCTION. Analysis of retrieved ceramic components have shown areas of localized ‘stripe wear’, which have been attributed to joint laxity and/or impingement resulting in subluxation of the head, causing wear on the edge of the cup. Studies have been conducted into the effects of mild subluxation, however few in vitro tests have looked at severe subluxation. The aim of this study was to develop a more clinically relevant subluxation protocol. MATERIALS & METHODS. Seven (Subluxation n=4; standard test n=3) of 36mm Biolox Forte (R3, Smith & Nephew) ceramic devices were tested for 0.5m cycles (mc). Two of the subluxed joints were further tested to 1 Mc. The devices were subjected to subluxation under standard testing conditions. The flex/ext was 30° and 15° respectively, with internal/external rotation of ±10°. The force was Paul type stance phase loading with a maximum load of 3 kN, and a standard ISO swing phase load of 0.3 kN at 1 Hz. The test was conducted on a ProSim hip joint wear simulator (SimSol, UK). The simulator is equipped with a novel mechanism to achieve translation of the head, to achieve subluxation. During the ISO swing phase load of 0.3kN, a controlled lateral force required for the translation of the head is applied by a cam mechanism, head retraction then occurs during heel strike. The lubricant used was new born calf serum diluted with de-ionised water to achieve average protein concentration of 20 g/l, with 0.2 wt % concentration NaN3, and changed every 250k cycles. Measurements have been taken at 0.5 & 1 mc stages. RESULTS. Linear wear measurements conducted on the subluxed joints resulted in stripe wear similar to that reported in vivo. Average length, width and depth dimensions were 25.34±1.96 mm, 8±1.60 mm and 16.95±3.87 μm (± 95% CL) respectively. Linear wear at 0.5 Mc for standard joints, were undistinguishable from the original profile. Gravimetrically, weight loss was undetectable for joints tested under standard conditions. The volume loss of the joints under subluxation was 1.9± 0.7 mm3 at 0.5 mc. Two joints tested to 1mc generated an average volume loss of 3.1±2.3 mm3. The stripe wear length, width and depth at 1 Mc were 25.30±3.33mm, 8±3.92mm and 35±17.07 μm respectiveley. DISCUSSION. The current study presents test results of a hip joint simulator with a novel subluxation mechanism to simulate severe and clinically relevant hip joint. Past techniques have had to reduce the swing phase load to achieve stripe wear patches of varying size and depth. The subluxed joints produced significantly higher volumetric wear than the standard joints. Dimensional measurements in terms of length, width and depth of wear patches of subluxed joints generated similar results to that which have been observed following retrieval analysis. Tests that can simulate different types of activity in hip joint simulators will help to improve the design and understanding of implant behaviour in vivo

Permanent patellar subluxation is treated with surgeries such as proximal realignment and distal realignment, however, it is difficult to cure this condition by using any methods. We performed mobile-bearing total knee arthroplasty (TKA) in a case of severe knee osteoarthritis complicated with permanent patellar subluxation since childhood, and obtained good results without performing any additional procedures. The patient was an 82-year-old woman with severe pain in the left knee. During the initial examination, the range of motion of the left knee joint was -10°of extension to 140°of flexion, and the Japanese Orthopaedic Association (JOA) score for knee osteoarthritis was 40 points (maximum score: 100). Preoperative radiographs showed a varus deformity in the left lower extremity with a femorotibial angle (FTA) of 188°, the axial view showed luxation of the patella. We performed TKA using a mobile-bearing implant. Intraoperative findings revealed that the central articular surface of the distal femur had disappeared, and that the patellar articular surface was concave and dome-shaped. The lateral patellofemoral ligament was released; this procedure was identical to that performed in conventional TKA. Postoperative radiographs showed good alignment, with an FTA of 173°. In the axial view, the patella was located in a reduced position at any angle of knee joint flexion. The postoperative range of motion of the left knee joint was 0°of extension to 130°of flexion. The patient was able to walk without the support of a T-shaped cane. There are many surgical treatments for permanent patellar subluxation. The appropriate treatment is selected according to the type and seriousness of the dislocation and the age of the patient. From the findings of the present case, we believe that in a case of knee osteoarthritis complicated with permanent patellar subluxation, surgery performed using a mobile-bearing implant would eliminate the necessity of performing additional proximal realignment and distal realignment

Background: Recurrent peroneal tendon subluxation is uncommon. We report the results of a delayed anatomic repair using suture anchors. Using a case series we tested the null hypothesis that there are no differences between pre- and post-operative status following anatomical repair of the superior peroneal retinaculum. Methods: In the period 1996 to 2001, we operated on 14 patients (all males; average age 25.3 ± 6.3 years, range 18–37) with traumatic recurrent unilateral peroneal tendon subluxation, with a followed up of 38 ± 3 (range 22 to 47) months. Results: No patient experienced a further episode of peroneal tendon subluxation, and all had returned to their normal activities. Maximum calf circumference, functional ability, peak torque, total work and average power of plantar flexion were always lower in the operated leg, but the differences did not reach statistical significance. The AOFAS Ankle-Hindfoot Scale increased significantly from 54.3 ± 11.4 to 94.5 ± 6.4 (p = 0.03), with five patients reporting a fully normal ankle. Conclusion: If an anatomic approach to treating the pathology is utilised, reattachment of the superior retinaculum is a most appropriate technique. It returns patients to a high level of physical activity, and gives high rate of satisfactory results both objectively and subjectively. Randomised control trials may be the way forward in determining the best surgical management method. However, the relative rarity of the condition and the large number of techniques make such a study difficult

Objective: Ex vivo studies have suggested that cartilage contact areas and pressure are of high clinical relevance in the ethiology of osteoarthritis in patients with patellar subluxation. The aims of this study were therefore to validate in vivo measurements of contact areas with 3D open magnetic resonance imaging (MRI), and to study knee joint contact areas in patients with patellar subluxation at different angles of knee flexion in comparison with healthy subjects. Methods: 3D-MR image data sets of 12 healthy volunteers and 8 patients with patellar subluxation were acquired using a standard clinical (1.5T) and an open (0.2T) MRI scanner. We compared femoro-patellar and femoro-tibial contact areas obtained with two different sequences from open MRI [dual-echo-steady-state (DESS) and fast-low-angle-shot (FLASH) sequences] with those derived from standard clinical 1.5 T MRI. We then analyzed differences in joint contact areas between healthy subjects and patients with patellar subluxation at 0, 30 and 90 of knee flexion using open MRI. Results: The correlation of the size of contact areas from open MRI with standard clinical MRI data ranged from r = 0.52 to 0.92. Open-MRI DESS displayed a smaller overestimation of joint contact areas (+21 % in the femoro-patellar, +12% in the medial femoro-tibial, and +19% in the lateral femoro-tibial compartment) than FLASH (+40%, +37%, +30%, respectively). The femoro-patellar contact areas in patients were significantly reduced in comparison with healthy subjects (− 47% at 0, − 56% at 30, and − 42% at 90 of flexion; all p < 0.01), whereas no significant difference was observed in femoro-tibial contact areas. Conclusions: Open MRI allows one to quantify joint contact areas of the knee with reasonable accuracy, if an adequate pulse sequences is applied. The technique permits one to clearly identify differences between patients with patellar subluxation and healthy subjects at different flexion angles, demonstrating a significant reduction and lateralization of contact areas in patients. In the future application of this in vivo technique is of particular interest for monitoring the efficacy of different types of surgical and conservative treatment options for patellar subluxation

Introduction. Clinical observations suggest mid-flexion instability may occur more commonly with rotating platform (RP) total knee arthroplasty (TKA), including increased revision rates and patient-reported instability and pain. We propose that increased gap laxity leads to liftoff of the lateral femoral condyle with decreased conformity between the femoral component and polyethylene (PE) insert surface leading to PE subluxation or dislocation. The objectives of this study were to define “at risk” loading conditions that predispose patients to PE insert subluxation or spinout, and to quantify the margin of error for flexion/extension gap laxity in preventing these adverse events under physiologic loading conditions. Methods. Biomechanical testing was performed on six fresh frozen cadaveric knees implanted with a posterior stabilized RP TKA using a gap balancing technique. Rotational displacement and torque were measured over time, while stiffness, yield torque, max torque and displacement were calculated using a post-processing, custom MatLab code. Revision with varying size femoral components (size 3–6) and PE insert thicknesses (10–15mm), by downsizing one step, were used to create a spectrum of flexion/extension gap mismatch. Each configuration was subjected to three loaded testing conditions (0°, 30° and 60° flexion) in balanced and eccentric varus loading, known to represent daily clinical function and “at risk” circumstances. Results. PE insert rotational instability was primarily determined by conformity and contact area between the femoral condyle and the upper surface of the PE insert. In this RP design, contact area is known to decrease with flexion greater than 35°, which predisposed to abnormal motion of the femur on PE insert (Figure 1). Under all flexion/extension gap testing conditions, PE insert rotational displacement significantly decreased with increasing knee flexion (differences ranged from 0.42 to 1.01cm, p<0.05), confirming that decreased conformity allows unintended motion to occur on the upper rather than the lower insert surface, as kinematically designed. This decrease in insert rotation was further exacerbated with eccentric medial-sided loading (differences ranged from 0.77 to 1.18cm, p<0.05). Yield torque (19.66±6.79N-m, p=0.033) and max torque (19.76±5.93N-m, p=0.014) significantly increased with increasing flexion from 0° to 60° under gap balanced conditions. Yield torque significantly decreased with greater flexion gap laxity at 60° of flexion (−24.82±5.96N-m, p=0.004). The depth of the lateral PE insert concavity (1.7–3.6mm) varied with insert size and thickness and determined femoral condylar capture. The lateral insert concavity defines a narrow margin of error in flexion/extension gap asymmetry leading to rotational insert instability, especially in smaller sized knees (size 3) where the jump height (1.7mm) is less than the insert sizing increment of 2.5mm. Conclusions. Contact area is known to decrease with flexion greater than 35° in this TKA-RP design. Flexion gap laxity further increased the risk of unintended top-side rotation of the femur on the insert, especially with increasing flexion and smaller components. In RP-TKA, in addition to medial-lateral gap symmetry and flexion-extension balance, a snug flexion gap with less than 2mm lateral laxity is critical to avoid insert instability and condylar escape with insert subluxation. For any figures or tables, please contact authors directly

Aims

Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with acetabular component positioning.

Background. Rotatory subluxation of the atlantoaxial joint has been thoroughly documented in children. However, pure traumatic atlantoaxial rotatory subluxation (TAARS) is a rare injury in adults with only a few cases reported in the English literature. Aim. To report two cases of TAARS in adults. Methods. A case note, clinical and radiological review. Results. Both patients were female. There was a history of a motor vehicle collision in both cases. There was no neurological impairment at presentation in either case. The injury in both cases was identified by plain X-ray and confirmed by CT scan. Both were managed by conservative treatment, initially with halo traction, followed by immobilisation in a rigid collar. Final clinical reviews occurred at 7 years and 2.5 years following injury. Neither patient had signs of C1-C2 instability or impaired neurology. Both patients, however, suffered headaches and occipital neuralgia, with stiffness and reduction in cervical spine movement. Conclusion. Traumatic rotatory subluxation in adults is a rare injury. It can pose a diagnostic challenge and CT scanning is mandatory for a correct evaluation of the C1-2 complex. Reduction and stability can be achieved through conservative treatment. However, it is evident from this short series that even early diagnosis and prompt reduction may not necessarily result in a good long term outcome in adult patients with TAARS

This is a retrospective study describing four patients who developed symptomatic subluxation of the hip after stabilisation to the pelvis for myopathic scoliosis in Duchenne Muscular Dystrophy (DMD). Fusion to the pelvis is recommended for treatment of scoliosis in DMD. Non-spinal extra-pulmonary complications following this have not been described. 4 patients (average age: 14 years) out of a cohort of patients who have undergone spinal stabilisation for DMD between 1991 and 1998 developed symptomatic subluxation of the hip at an average of three months after fusion from the upper thoracic spine to the pelvis. All four had pain and three noticed clicking in the hip. X-rays revealed subluxation of the hip in all patients, and conservative treatment by adjustment of seating position in the wheelchair was successful in reducing the symptoms in all patients. Flexion-abduction contractures of the hip, which are a feature of DMD, are known to cause uncovering of the contralateral hip. We postulate that the spine compensates for this uncovering to a large degree, and that spinopelvic fusion for scoliosis in patients with pre-existent abduction contractures negates the capacity of the spine to provide compensation. This leads to uncovering of the hip with the lesser degree of contracture, and the resultant symptoms. We recommend screening for, and treatment of, flexion-abduction contractures of the hip in all patients undergoing spinal fusion for DMD, to avoid the possibility of development of symptomatic subluxation of the hip

Objective: To review the hip subluxations or dislocations occurring during femoral lengthening in patients with congenital longitudinal lower limb deficiencies. Methods: Sixty-three patients with congenital longitudinal lower limb deficiencies underwent femoral lengthening using either De Bastiani, Villarubias or Ilizarov technique. Acetabular index, medial joint space, CE angle of Wiberg, acetabular angle of Sharp and neck-shaft angle were measured on anteroposterior radiographs of hip before, during and after lengthening. The Acetabulum was considered dysplastic when the Sharp angle was more than 45 degrees. Hip was considered to be subluxed when the medial joint space increased during lengthening. Results: During femoral lengthening, eleven hips sub-luxed as measured by the increase in medial joint space and one hip dislocated. All these hips had a preoperative acetabular index more than 25 degrees, CE angle less than 20 degrees and Sharp angle more than 45 degrees. The average neck-shaft angle was 75 degrees. Following subluxation, lengthening was stopped and the hips were reduced in hip spica after adductor and sartorius tenotomies. In one patient femoral shortening and acetabulo-plasty had to be done to reduce the subluxation. No case of avascular necrosis was noted. Conclusion: Hip subluxation during femoral lengthening of congenital longitudinal lower limb deficiencies tends to occur when the acetabular index is more than 25 degrees, Sharp angle is more than 45 degrees, CE angle is less than 20 degrees and when there is associated femoral coxa vara. Careful preoperative assessment is required, and if need be hip reconstruction prior to lengthening. Close monitoring during lengthening is recommended

Traumatic rotatory atlanto-axial dislocation and subluxations are rare injuries. The diagnosis is often missed or delayed because of subtle clinical signs. Head tilt makes the interpretation of plain radiographs difficult. Delayed diagnosis often results in chronic instability necessitating surgical stabilization. A hitherto undescribed clinical sign was evaluated which should lead to increased awareness and avoid delay in the diagnosis. Why a new clinical sign?. Easily missed injury. Uncommon but not that uncommon. Difficult to diagnose. Needs high index of suspicion. Not much emphasis given in training. Radiographs usually inconclusive because of torticollis deformity Prerequisites for test. Patient should be conscious. A Lateral radiograph should not show any facet dislocations or fractures in cervical spine. Explain the patient what you intend to do and he/she should report any paraesthesias, sensory or motor symptoms if felt during the test Clinical sign- Elastic Recoil:. Supine patient. Hold head carefully with hands on either side of the head. Instruct patient to report any neurological deterioration. Try to straighten the head tilt gently. Once it is corrected, release the supporting hand towards tilt of the head taking care not to let the head overshoot the original position. An elastic recoil of the head to previous position indicates a positive test. Methods: This study was carried out between 1997 to 2003. The test was applied to 59 patients presenting in Accident and Emergency. All this patients had head tilt even after the application of a hard cervical collar. All the 59 patients had CT scans to confirm or exclude the diagnosis of Rotatory atlanto axial dislocation/subluxation. Results: The new clinical sign was found to be positive in all the fourteen patients with atlanto- axial rotatory dislocations/subluxations which was confirmed by CT scan. The test was also found to be positive in 5 patients with unilateral facet joint dislocation. The sensivity of the test in our study was 100%. The specificity was 89%, positive predictive value 0.73, negative predictive value 0.9 (90%). Conclusion: This new clinical sign may help in early recognition of the injury and also act as an effective screen to indicate which patient needs a CT scan to confirm the diagnosis. This can also be applied in places where the CT scan facilities are not readily available especially in the developing nations

Background. Current literature of definition, classification and outcomes of fractures of talar body remains controversial. Our primary purpose is to present an unusual combination of fractures of talar body with pantalar involvement / dislocation / extension as a basis for modification of Müller AO / OTA Classification. Methods. We include four consecutive patients, who sustained talar body fractures with pantalar subluxation/dislocation /extension. These unusual injury patterns lead us to reconsider Müller AO / OTA Classification in the light of another widely used talar fracture classification, Hawkins Classification of fractures of neck of talus and subsequent modification by Canale and Kelly. Results. Müller AO / OTA Classification comprises CI – Ankle joint involvement, C2 – Subtalar joint involvement, C3 – Ankle and subtalar joint involvement. We propose Modification of Müller AO / OTA. Classification. C1 – Absolutely undisplaced fracture; C2 – Ankle and Subtalar joint involvement: subluxation; C3 – Ankle and subtalar joint involvement: subluxation with comminution; C4 – Ankle, subtalar and talonavicular joint involvement. Conclusions. Our modification redefines Müller AO / OTA Classification, extends and fills the void in the classification by inclusion of C4, draws attention to stability of talonavicular joint and reflects increasing severity of injury in fractures of talar body

Introduction: The efficacy and complications of the transarticular screw procedure have been reported by many authors. However, few have reported this procedure for child younger than 10 years old. We have treated two children for atlantoaxial subluxation with transarticular screws, using a soft collar without a halo-vest, and have achieved bone union in good reduced position. Methods/results. Case 1: a 5-year-old boy with mental retardation and cerebellar infarction due to an insufficiency of the vertebral artery resulting in severe atlantoaxial instability. He presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum. He has been treated with transarticular screw and iliac bone graft by Brooks procedure. Case 2: an 8-year-old boy with congenital spondyloepiphyseal dysplasia and a right valgus knee. He, too, presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum, and has been treated with transarticular screw and iliac bone graft by Brooks procedure. In both cases, we used two half-thread cortical screws with a diameter of 2.7mm and a length of 30mm for the transarticular screw procedure. Discussion/conclusion: Rigid external fixation was obtained by Halo-vest. This method, however, would be expected to cause mental stress for the child patient and the family. More rigid internal fixation would be required to resolve this problem. More rigid internal fixation can be obtained with the transarticular screw, and postoperative orthosis can be performed easily, without the need for a Halo-vest

Scoliosis and hip subluxation/dislocation are common and often coexistent problems encountered in patients with cerebral palsy (CP). The underlying mechanism may be related to muscle imbalance. Surgical correction may become necessary in severe symptomatic cases. The effect of surgical correction of one deformity on the other is not well understood. We retrospectively reviewed a series of 17 patients with total body cerebral palsy with diagnoses of both scoliosis and hip subluxation who had undergone either surgical correction of their scoliosis (9 patients) or a hip reconstruction to correct hip deformity (8 patients). In all patients, the degree of progression of both deformities was measured, radiographically, using the Cobb angle for the spine and the percentage migration index for hip centre of rotation at intervals before and at least 18 months post surgery. All patients who underwent scoliosis correction had a progressive increase in the percentage of hip migration at a rate greater than that prior to scoliosis surgery. Similarly, patients who underwent a hip reconstruction procedure demonstrated a more rapid increase in their spine Cobb angles post surgery. There may be a relationship between hip subluxation/dislocation and scoliosis in CP patients. Surgery for either scoliosis or hip dysplasia may in the presence of both conditions lead to a significant and rapid worsening of the other. The possible negative implications on the overall functional outcome of the surgical procedure warrants careful consideration to both hip and the spine before and after surgical correction of either deformity. In selected cases there may be an indication for one procedure to follow soon after the other

Aim: To evaluate the necessity for further radiological investigation in patients with suspicion of rotatory subluxation of the atlanto-axial complex on plain radiography following acute cervical trauma. To outline guidelines for assessment of patients with atlanto-axial asymmetry on plain radiography. Methods: A retrospective review of all patients who had undergone atlanto-axial CT scanning as a result of radiographic C1–C2 asymmetry following cervical spine trauma in the 3 year period from January 1999 to December 2001. The plain X-ray and CT images were reviewed retrospectively and correlated with their clinical presentation and outcome by the senior author. Results: Twenty-eight patients were included in the study. Acute cervical spine trauma had occurred most commonly following a road traffic accident. No patient was found to have acute cervical spine torticollis or severe cervical pain. Patients age ranged from 21–44 years (M:F – 15:13). All patients were found to have atlanto-odontoid asymmetry on initial plain X-ray. No patients were found to have rotatory subluxation on CT images. 3 patients were found to have minor degrees (< 10°) of rotation on the CT scan which is within normal limits. 9 patients (32%) were found to have congenital odontoid lateral mass asymmetry. All patients were treated conservatively and had no further intervention. All plain radiographs were then assessed to determine the underlying reason for asymmetry. In 19 cases the orientation of the radiographic beam in combination with head rotation was found to be at fault. Conclusion: Rotatory subluxation of the cervical spine is a rare but serious condition in the adult. The condition is suspected radiologically in the presence of odontoid lateral mass asymmetry on open mouth view. The application of ATLS principles in the initial assessment of trauma patients has resulted in a significant increase in the number of radiological examinations performed. This has led inevitably to an increase in the number of anomalies identified. An average of 400 c-spine X-rays per year are performed for trauma in our casualty department. In this study, we have identified 9 patients out of a total of 29 with congenital odontoid lateral mass asymmetry over a 3 year period. This represents approximately 0.75% of the cervical spine X-rays and should be considered in the differential diagnosis following acute cervical trauma. We outline guidelines for recognising benign atlanto-axial asymmetry

Aims: To review the hip subluxations or dislocations occurring during femoral lengthening in patients with congenital longitudinal lower limb deficiencies. Methods: Sixty-three patients with congenital longitudinal lower limb deficiencies underwent femoral lengthening using either De Bastiani, Villarubias or Ilizarov technique. Acetabular index, medial joint space, CE angle of Wiberg, acetabular angle of Sharp and neck-shaft angle were measured on anteroposterior radiographs of hip before, during and after lengthening. Acetabulum was considered dysplastic when the Sharp angle was more than 45 degrees. Hip was considered to be subluxed when the medial joint space increased during lengthening. Results: During femoral lengthening, eleven hips subluxed as measured by the increase in medial joint space and one hip dislocated. All these hips had a pre-operative acetabular index more than 25 degrees, CE angle less than 20 degrees and Sharp angle more than 45 degrees. The average neck-shaft angle was 75 degrees. Following subluxation, lengthening was stopped and the hips were reduced in hip spica after adductor and sartorius tenotomies. In one patient femoral shortening and acetabuloplasty had to be done to reduce the sub-luxation. No case of avascular necrosis or chondrolysis was noted. Conclusions: Hip subluxation during femoral lengthening of congenital longitudinal lower limb deficiencies tends to occur when there is associated ace-tabular dyplasia and femoral coxa vara. Careful preoperative assessment, if need be hip reconstruction prior to lengthening and close monitoring during lengthening is recommended

Introduction: When we have operate children’s knee in habitual luxation of the patella we noted, that iliotibial band have branch going to patella and to patella tendon. It is important to the etiopathology of the patella luxation, but in valgus of the knee and in hyperpresion of the patella syndrome too. Material and Method: In years 2000–2007 we have performed surgical iliotibial band release In 70 children, 28 boys and 42 girls. In 19 children contracture of the iliotibial band were one-sided, in 51 children contracture were both-sided. Patients were divided in to groups with various pre-operative symptoms:. valgus of the knee – 40 patients (74 legs),. valgus of the knee with subluxation of the patella in extension of the knee – 18 (31 legs),. valgus of the knee with hyperpression of patella syndrome – 11 (15 legs),. pathological knee valgity 1 (1 leg). In all cases we performed surgically release of the iliotibial band. The incision was 5–10 cm over the joint space on the lateral side of the femur. The fasciotomy of the fascia lata and iliotibial band we make in “Z” shape. During operation we flex and extend the knee to be sure all fibres are released. Findings: We have check late result (3 – 36 month postoperatively) in 45 patients (77 legs). We estimate:. 27 patients from group of valgus deformity of the knee. 14 patients from group of valgus of the knee with subluxation of the patella. 3 patients with group of valgus of the knee with hyperpression of patella syndrome. 1 patient with pathological knee valgity. The valgus angle preoperatively reaches 12 to 35 (on average 16 for right leg and 16,5 for left). Postoperatively angle improve in all patients. Knee angle change from 5 to 20 degree (on average 8,4 for Wright leg, 8,3 for left). In group with patella subluxation we have check 23 legs. In 11 patents (18 legs) the angle improve. The 3 patients (5 leg) later has full reconstruction of patello-femoral joint with patella tendon transposition. In patient with post inflammatory deformation the angle improve from 15 to 7 degree, but after next 34 month reaches again 20 degree and patient had osteotomy of the femur. Conclusions:. iliotibial band release show us good result in correction the axis of the knee, first even during operation. After iliotibial band release is possible to move patella passive to medial side of the knee. Late result show us good effect in group of valgus of the knee deformity and in group with hyperpression of the patella syndrome. In group of subluxation of the patella effectivity of this method is 78%. We believe that surgical release of iliotibial band is easy and effective method of knee valgus correction in idiopathic valgity or in patella subluxation and in hyperpression of the patella syndrome

This study of retrieved 28 mm Metasul™ (cemented) revealed for the first time adverse wear effects created by impingement-subluxation in MOM. The 10 cases selected (with femoral stems) had annual follow-up 3–11 years. (1) Unequivocal evidence here shows that all heads routinely subluxed from the Metasul liners. Femoral stems revealed well-demarcated notches (DN) on necks and trunnions (Fig. 1a: n = 6), shallow cosmetic blemishes (Fig. 1b CB: n = 4), and abrasion by cement (Fig. 1b: PMMA). As demonstrated by EOS radiographs, impingement locations varied with implant positioning, pelvic mobility and patient functionality – both anterior and posterior notching (Fig. 1). The first impingement notch occurred with head located (Fig. 2a), whereas the head had subluxed from the cup at 2. nd. notch (Fig. 2b). The model demonstrated that patients gained 20° motion by such head-subluxation manoeuvres. It was surprising that there was no collateral damage evident on the liners. Even with severe notching of Ti6Al4V and CoCr stems, the cup rims generally appeared well-polished. Femoral heads revealed macro-stripe damage on articular surfaces (Fig. 3), as did cups. Basal and polar macro-stripes on heads were always located at hip impingement positions. The equatorial stripes were formed at main-wear zone boundaries. Thus equatorial stripes were likely created by some form of rim-impact damage (micro-separation) or by local ingress of 3. rd. -body wear particles under the cup rim. Micro-grooving was evident within these macro-size stripes and frequently featured large raised lips (Fig. 3), interpreted as signs of adverse 3. rd. -body wear mechanisms, and rarely described.(2) It would appear that large metal particulates were released during MOM impingement-subluxation manoeuvres and circulated the hip joint to producing severe 3. rd. -body abrasion. Gradual decomposition of such large debris to nano-sized particulates under joint loading would then produce the often-referenced ‘self polishing’ effect of CoCr. EDS studies revealed metal smears on the CoCr surfaces containing the elements of titanium alloy (Ti, Al, V). This was further evidence of impingement-subluxation manoeuvres.(1, 3). In-vivo cup wear patterns also appeared much larger than those produced in MOM simulators. Such differences likely reflected head-subluxation in vivo, whereby heads unconstrained by the subluxation maneuver were free to orbit up and even cross cup rims, i.e. “edge wear”. This appears to be the first study detailing the adverse wear mechanisms in MOM bearings. There are two limitations to our retrieval study, a) these wear results may not be representative for all MOM designs, and b) it is unknown whether such results have relevance to MOM cases continuing successfully