Aims: Prior research has demonstrated that currently available total ankle implants fail to restore physiologic joint mobility. Most of the modern mobile-bearing designs that feature a flat tibial component and a talar component with anatomic curvature in the sagittal plane function non physiologically with the natural ligament apparatus. The aims of this investigation were a) to elucidate the natural relationship between ligaments and articular surfaces at the intact human ankle joint and b) to develop a new design of total ankle replacement able to replicate this relationship between the retained ligaments and the implanted prosthetic components.

Methods: Motion during passive flexion was analyzed in ten skeleto-ligamentous lower leg preparations including tibia, fibula, talus, calcaneus and intact ligaments. Geometry of ligament fiber arrangement and articular surface shapes was obtained with a 3D digitizer (FARO Technologies, Inc.). A sagittal four-bar linkage model was formulated as formed by the tibia/fibula and talus/ calcaneus rigid segments and by the calcaneofibular and tibiocalcaneal ligaments. To test the ability of possible new prostheses to reproduce the compatible mutual function between the articulating surfaces and the ligaments retained, non-conforming two-component and fully-conforming three-component designs were analyzed. A new total ankle replacement has been designed, prototypes manufactured and implanted in seven skeleto-ligamentous lower leg preparations, and motion was observed. A corresponding new prosthesis has been produced (Finsbury, UK), and implanted in four patients.

Results: The articular surfaces and the ligaments alone prescribed joint motion into a preferred single path of multiaxial rotation (one degree of unresisted freedom). Fibers within the calcaneofibular and tibiocalcaneal ligaments remained most isometric throughout the passive range. The four-bar linkage model well predicted the sagittal plane kinematics observed in corresponding experiments. A ligament-compatible, convex-tibia, fully-congruent, three-component prosthesis design showed the best features: complete congruence over the entire range of flexion together with an acceptable degree of entrapment of the meniscal bearing. Restoration of natural joint kinematics and ligament recruitment was observed in all replaced ankles.

Conclusions: The overall investigation is demonstrating that a profound knowledge of the changing geometry of the joint passive structures throughout the range of passive flexion (mobility) is mandatory for a successful design of joint replacements.

Aims:Understanding total knee replacement mechanics and their influence on patient mobility requires accurate analysis of both operated joint accurate kinematics and full body kinematics and kinetics. The main aim of this study is to perform these two analyses conjointly, as never been reported previously. An innovative graphic-based interface is also pursued aimed at supporting quantitative functional assessment of these patients during the execution of daily living motor tasks in a single synchronized view.

Methods: Three-dimensional fluoroscopic and gait analysis were carried out on eleven patients with PCL-retaining mobile bearing (Interax ISA, Stryker / How-medica / Ostetonics) and on ten posterior stabilized fixed bearing (Optetrak PS, Exactech) knee prostheses. Patients performed three trials of stair ascent twice on the same day: first in the radiology department for fluoroscopy acquisition and later in the Movement Analysis Laboratory, utilizing an identical staircase. Three-dimensional fluoroscopic analysis entails reconstruction of absolute and relative positions and orientations of the two metal components in space by analyzing series of fluoroscopic images of the operated knee and utilizing knowledge of the 3D cad models of these components. Conventional stereophotogrammetry and dynamometry were used to calculate kinematics and kinetics of the trunk, pelvis and of the major joints of the lower limb. An advanced computer-based interface was developed (MULTIMOD, EU-funded project: IST-2000-28377) to show together a) original video of the patient tasks, b) 3D graphical representation of bony segment motion, c) original fluoroscopic images, d) 3D reconstruction of prosthesis component relative motion, and e) graphical transverse plane representation of the contact areas at the base-plate of the replaced knee. All these were registered in space and synchronized in time.

Results: No significant statistical differences on clinical data were found between the two patient populations. Observations at the interface allowed distinct identification of the most critical phases of the task and of the most common compensatory mechanisms utilized by these patients. Statistically significant correlation was found between knee flexion at foot strike and the position of the mid-condylar contact points, and between maximum knee adduction moment and corresponding lateral trunk tilt.

Conclusions: A more complete and powerful assessment of the functional performances of different TKR designs is obtained by combining gait and fluoroscopic in-vivo analyses, which provide correlated and synergic quantitative information.

Although dynamic hip screw (DHS) is considered the treatment of choice for pertrochanteric fractures, we theorized that external fixation would produce clinical outcomes equal to, if not better than, outcomes obtained with conventional treatment. As external fixation is minimally-invasive, we expected a lower rate of morbidity and a reduced need for blood transfusions. We compared fixation with DHS vs. Orthofix pertrochanteric fixator (OPF) in elderly pertrochanteric fracture patients. Forty consecutive pertrochanteric fracture patients were randomized to receive either 135A1 4-hole DHS (Group A) or OPF with 4 HA-coated pins (Group B). Inclusion criteria were: female, age B3 65 years, AO type A1 or A2 and BMD less than −2.5 T score. There were no differences in patient age, fracture type, BMD, ASA, hospital stay or quality of reduction. Operative time was 64 B1 6 minutes in Group A and 34 B1 5 minutes in Group B (p < 0.005). Average number of post-operative blood transfusions was 2.0 B1 0.1 in Group A, and none in Group B (p < 0.0001). Pain was measured 5 days post-operatively and was lower in Group B (p < 0.005). Fracture varization at 6 months was 6 B1 8A1 in Group A and 2 B1 1A1 in Group B (p = 0.002). In Group B, no pin-tract infections occurred. Pin fixation improved over time, as shown by pin extraction torque (2770 B1 1710 N/mm) greater than insertion torque (1967 B1 1254 N/mm), (p= 0.001). Harris hip score at 2 years was 62 B1 20 in Group A and 63 B1 17 in Group B. This study shows that OPF with HA-coated pins is an effective treatment for this patient population. Operative time is brief, blood loss is minimal, fixation is adequate and the reduction is maintained over time.

The purpose of this study is to demonstrate the validity of the autologous chondrocytes transplantation (A.C.T.) technique implemented over the last 6 years in the treatment of osteochondral lesions of the talus.

Our case study included 22 patients (12 males and 10 females), with an average age of 27 years affected by osteochondral lesions of the talus surface. All lesions were > 1.5 cm2, monofocal, and post-traumatic in origin. The first 9 patients received ACT (Genzyme technique) and the remaining 13 patients received ACT with an arthroscopic technique. In 6 of the patients, the cartilage harvested from the detached osteochondral fragment was used for culturing, avoiding the first step arthroscopy in the knee. Before surgery, all patients were assessed clinically, radiographically, and using MRIs. For clinical evaluation patients were assessed using the American Foot & Ankle Society 100 point score. Before surgery the mean score was 48.4 points. 11 patients underwent second-look arthroscopy at one year during which a biopsy was harvested for histologic analysis of the reconstructed cartilage. Of these, 9 patients (Genzyme technique) also had hardware removed.

The mean follow-up of the 22 patients was 36 months. At follow-up, all patients but one were satisfied with their results. With regards to the clinical results evaluated using the American Foot and Ankle Society score, an average of 90.5 was obtained at 24 months, while at 36 months the average score (19 patients) was 94.0 (range 54–100). During follow-up arthroscopy, 4 patients had mild fibrosis and 1 patient required regularization of flap overgrowth causing pain.

The clinical and histological results have confirmed the validity of the surgical technique utilized with no subjective nor objective complications. An improvement of the symptoms and of articular function has also been observed: laboratory data confirmed the histological appearance of the newly formed hyaline cartilage in all cases evaluated. Immunohistochemistry showed a positive staining for collagen type II located in the extracellular matrix and in the chondrocytes in the healthy and transplanted cartilage biopsies. All the specimens studied were also positive for proteoglycans expression as was the Alcian blue reaction, which highlighted the presence of these fundamental components of a cartilaginous matrix.

Aims: The pourpose of this study is to review a series of A2 intertrochanteric fractures in old, obese osteoporotic patients treated by total hip arthroplasty. Methods: 52 patients with A2 intertrochanteric fracture aged ≥ 75 years, mentally healthy, with BMD lower than 2.5 T score and Body Mass Index ≥30 were selected. They were 40 female and 12 males, aged 82±5 years with Body Mass Index of 32±2. Through a Hardinge approach to the hip, the femoral head was removed and a cemented cup and stem were implanted. Then the greater trochanter fragments were fixed by cerclage. The lesser trochanter fragment was not fixed. Medius gluteus muscle fibers were sutured to the greater trochanter and to the vastus lateralis muscle. All patients were allowed weight bearing as soon as possible after surgery. Results: No surgical complications were observed. Average Harris Hip Score at 1 month was 63±9 at 3 months 77±6 and at 1 year 78±7, at 5 years follow up 76±14 in the 24 patients still alive. None of the other died for causes related to the interthrocanteric fracture. Average return to normal daily activity time was 27±5 days. Conclusions: Total hip arthroplasty is a safe procedure for treatment of old, obese osteoporotic patients affected by A2 intertro-chanteric fractures. In fact, no failure occurred in any of the patients allowed unrestricted weight bearing from the first day after surgery. Moreover, they could return to normal daily activity in less than 5 weeks.

Aims: The purpose of this paper is to review a series of ankle post-traumatic deformities treated by arthroplasty, þbula lengthening, bone graft and correction of the malunion. Methods: 30 cases, mean age 40 (±15), were operated 6–30 months after injury and followed up at 5 years. Clinical Maryland foot score (MFS) and X-ray evaluation were performed pre op and at follow up. After medial revision of bone and soft tissue structures, through a lateral transmalleolar approach, mal-union of the posterior malleolus or sinking of the lateral tibial plafond were corrected using autologous cortical cancellous bone graft covered by its periosteal ßap. Postoperative treatment consisted of immediate continual passive motion weightbearing allowed after an average of 8–12 weeks after surgery. Results: Pre op MFS was 64±8 and post-op it was 82±11. 11 patients had excellent results with normal range of motion, no pain, and no progression of the arthritis. The result in 9 cases was good with a normal range of motion, little pain after long walk, and no progression of arthritis. 7 cases were fair because of a decrease in the range of motion and progression of arthritis and moderate pain. 3 poor cases needed arthrodesis. Conclusions: Fibula lengthening, bone graft and correction of malunion were effective treatment of ankle post-traumatic valgus deformity in order to delay ankle fusion in young patients. The success of the procedure was correlated to the severity of arthritis and the joint congruity obtained by surgery.

Aims: Our purpose was to determine if DHS fixed with hydroxyapatite (HA)-coated AO/ASIF screws improves fixation and clinical outcomes in osteoporotic trochanteric fracture patients. Methods: 120 osteoporotic patients with trochanteric fractures were randomized to receive 135° 4-hole DHS fixed with either standard lag and cortical stainless-steel AO/ASIF screws (Group A) or HA-coated lag and cortical stainless-steel AO/ASIF screws (Group B). Inclusion criteria were: female; age ≥65 years; AO type A1 or A2; and BMD lower than -2.5 T score. Results: Tip Apex Distance (TAD) was 22±4mm in Group A and 23±5mm in Group B (ns). In Group A there were 4 cut-out cases and none in Group B (p< 0.05, β=0.8). Post-op (ns) and 6 month (p=0.008) femoral neck-shaft angle was 134±5° and 129±7° (Group A) and 134±7° and 133±7° (Group B). At 6 months, Harris Hip Score was 63±22 (Group A) and 71±18 (Group B) (p=0.02). Conclusions: HA-coated AO/ASIF screws prevent fracture varization and lag screw cutout, thus improving clinical outcomes in osteoporotic trochanteric fracture patients.

Aims: We compared treatment with external fixation (EF) vs DHS in osteoporotic trochanteric fractures. Methods: 40 patients were randomized to receive either 135° 4-hole DHS (Group A) or an Orthofix trochanteric external fixator with 4 hydroxyapatite-coated Osteotite pins (Group B). Inclusion criteria were: female, age ≥65 years, AO fracture type A1-2 and BMD lower than -2.5T score. Fixators were removed at 3 months. Results: There were no differences in patient age, fracture type, BMD, ASA, hospital stay, or quality of reduction. Operative time was 64±6 minutes in Group A and 34±5 minutes in Group B (p< 0.005). Average number of blood transfusions was 2±0.1 in Group A, and none in Group B (p< 0.0001). Fracture varization at 6 months was 6±8° in Group A and 2±1° in Group B (p=0.002). Harris Hip Score was 62±20 in Group A and 63±17 in Group B (ns). In Group B, no pin-track infections occurred. Pin fixation was maintained over time, as shown by no differences between pin extraction and insertion torque. Conclusions: We consider EF a viable treatment option for this patient population. Operative time is short, postoperative complications are minimized, and fixation is improved.

Aims: The purpouse of the study is to review a series of hallux valgus treated by minimally invasive distal metatarsal osteotomy with a simple, effective, rapid, inexpensive (SERI) technique. Methods: 54 consecutive feet in 37 patients, aged 48 ± 23 years affected by hallux valgus deformity less than 40û with an intermetatarsal angle up to 20û were reviewed at 5 years follow up. Surgical technique consisted of a 1 cm medial incision at the metatarsal neck, then an osteotomy was performed using an oscillating saw. With a direct line of vision, all characteristics of the deformity (HVA, IMA, DMAA) were corrected by lateral displacement of the metatarsal head; contemporary plantar or dorsal displacement was performed according to insufþciency or overloading of the þrst ray. The osteotomy was stabilized by a 2 mm Kirschner wire. All patients were clinically (AOFAS score) and radiographically checked at an average follow up of 5 years. Results: The clinical score at follow up was (91±12). The pre-op hallux valgus angle was 32.5±9, while post-op it was 22±7 (p< 0.0001), pre-op inter-metatarsal angle was 13±3, while post op it was 9±3 (p< 0.0001), the pre-op distal metatarsal articular angle was 19±10, while post-op it was 9±7 (p< 0.0001). Conclusions: Clinical and radiographic þndings showed that SERI osteotomy permitted an adequate correction of all the pathologic characteristics of the deformity, and this factor is responsible for our satisfactory results.

Only recently has the mobility of the ankle joint been elucidated. Sliding/rolling of the articular surfaces and slackening/tightening of the ligaments have been explained in terms of a mechanism guided by the isometric rotation of fibres within the calcaneofibular and tibiocalcaneal ligaments. The purpose of this investigation was to design a novel ankle prosthesis able to reproduce this physiological mobility.

A four-bar linkage computer-based model was used to calculate the shapes of talar components compatible with concave, flat and convex tibial components and appropriate fully congruous meniscal bearings. Three-component designs were analysed, and full congruence of the articular surfaces, appropriate entrapment of the meniscal bearing and isometry of the two ligaments were required.

A convex tibial component with 5 cm arc radius gave a 2 mm entrapment together with a 9.8 mm amount of tibial bone cut, while maintaining ligament elongation within 0.03 % of the original length. The physiological patterns of joint motion and ligament tensioning were replicated. The talar component slid backwards while rolling forwards during dorsiflexion. These movements were accommodated by the forward displacement of the meniscal bearing on the tibial surface under the control of the ligaments. The complementary surfaces provide complete congruence over the entire range of flexion, such that a large contact area is achieved in all positions.

To restore the physiological mobility at the ankle joint, not only should the components be designed to be compatible with original ligament pattern of tensioning, but also these should be mounted in the appropriate position. A suitable surgical technique was devised and relevant instrumentation was manufactured. Five below-knee amputated specimens replaced with corresponding prototype components showed good agreement with the model predictions.

Current three-component designs using a flat tibial component and physiological talar shapes cannot be compatible with physiological ligament function.

We compared thirty-eight patients from three orthopaedic centres who had external fixation of the femur or the tibia. Patients were randomised to receive standard (tapered 5/6 millimeter) pins (Group A) or OsteoTite (hydroxyapatite coated tapered 5/6 mm) pins (Group B).

In Group A there were 18 patients who received 71 pins. Average age of the patients was 49±12 years. Three patients had external fixation in the femur and 15 in the tibia. External fixation was used in three types of treatment: fracture fixation (4), knee osteotomy (12), and bone-transport (2). Two different fixator frames were used: a unilateral fixator was mounted in 15 patients and a circular fixator in three patients. In Group B, 20 patients (average age: ± 48 years) received 86 pins. Four patients had external fixation in the femur and 16 in the tibia. External fixation was used in three types of treatments: fracture fixation in three patients, knee osteotomy in 13 patients, and bone-transport in four patients. Two different fixator frames were used: a unilateral fixator was mounted in 16 patients and a circular fixator in four patients.

No significant difference regarding sex, age, external fixation treatment type, external fixation frame, and length of treatment were observed between the two groups. Mean final pin insertion torque was 477 ± 214 Newton cm in Group A and 339 ± 184 in Group B (p< 0.01). Mean pin extraction torque was 205 ± 169 Newton cm in Group A and 532 ± 211 in Group B (p< 0.01). Pin extraction torque was significantly lower compared to the corresponding insertion torque in Group A (p< 0.01). Pin extraction torque was significantly higher compared to the corresponding insertion torque in Group B (p< 0.01). Pin tract infection rate was lower in Group B compared to Group A (p< 0.01).

This study shows that hydroxyapatite coating was clinically effective in the improvement of the bone pin interface strength of tapered pins. By using these pins, deterioration of the bone pin interface strength can be avoided and external fixation complications minimised.