Aim

Aim of this monocentric, prospective study was to evaluate the safety, efficacy, clinical and radiographical results at 24-month follow-up (N = 6 patients) undergoing hip revision surgery with severe acetabular bone defects (Paprosky 2C-3A-3B) using a combination of a novel phase-pure betatricalciumphosphate - collagen 3D matrix with allograft bone chips.

Restoration of natural range and pattern of motion is the primary goal of joint replacement. In total ankle replacement, proper implant positioning is a major requirement to achieve good clinical results and to prevent instability, aseptic loosening, meniscal bearing premature wear and dislocation at the replaced ankle. The current operative techniques support limitedly the surgeon in achieving a best possible prosthetic component alignment and in assessing proper restoration of ligament natural tensioning, which could be well aided by computer-assisted surgical systems. Therefore the outcome of this replacement is, at present, mainly associated to surgeon's experience and visual inspection. In some of the current ankle prosthetic designs, tibial component positioning along the anterior/posterior (A/P) and medio/lateral axes is critical, particularly in those designs not with a flat articulation between the tibial and the meniscal or talar components. The general aim of this study was assessing in-vitro the effects of the A/P malpositioning of the tibial component on three-dimensional kinematics of the replaced joint and on tensioning of the calcaneofibular (CaFiL) and tibiocalcaneal (TiCaL) ligaments, during passive flexion. Particularly, the specific objective is to compare the intact ankle kinematics with that measured after prosthesis component implantation over a series of different positions of the tibial component.

Four fresh-frozen specimens from amputation were analysed before and after implantation of an original convex-tibia fully-congruent three-component design of ankle replacement (Box Ankle, Finsbury Orthopaedics, UK). Each specimen included the intact tibia, fibula and ankle joint complex, completed with entire joint capsule, ligaments, muscular structures and skin. The subtalar joint was fixed with a pin protruding from the calcaneus for isolating tibiotalar joint motion. A rig was used to move the ankle joint complex along its full range of flexion while applying minimum load, i.e. passive motion. In these conditions, motion at the ankle was constrained only by the articular surfaces and the ligaments. A stereofotogrammetric system for surgical navigation (Stryker-Leibinger, Freiburg, Germany) was used to track the movement of the talus/calcaneus and tibial segments, by using trackers instrumented with five active markers. Anatomical based kinematics was obtained after digitization by an instrumented pointer of a number of anatomical landmarks and by a standard joint convention. The central point of the attachment areas of CaFiL e TiCaL was also digitised. Passive motion and ankle joint neutral position were acquired, and the standard operative technique was performed to prepare the bones for prosthesis component implantation. The final component for the talus was implanted, the tibial component was initially positioned well in front of the nominal right (NR) position, the meniscal bearing was instrumented with an additional special tracker, and passive motion was collected again in passive flexion. Data collection was repeated for progressively more posterior locations for the tibial component, for a total of six different locations along the tibial A/P axis: three anterior (PA), the NR, and two more posterior (PP), approximately 3 to 5 mm far apart each. The following three-dimensional kinematics variables were analyzed: the three anatomical components of the ankle joint (talus-to-tibial) rotation (dorsi/plantar flexion, prono/supination and internal/external rotation respectively in the sagittal, frontal and transverse planes), the meniscal bearing pose with respect to the talar and tibial components, the ‘ligament effective length fraction’ as the ratio between the instantaneous distance between the ligament attachment points and the corresponding maximum distance, and the instantaneous and mean helical axes in the tibial anatomical reference frame.

In all specimens and in all conditions, physiological ranges of flexion, prono/supination and internal/external rotation were observed at the ankle joint. A good restoration of motion was observed at the replaced joint, demonstrated also by the coupling between axial rotation and flexion and the physiological location of the mean helical axis, in all specimens and in most of the component positions. Larger plantar- and smaller dorsi-flexion were observed when the tibial component was positioned more anteriorly than NR, and the opposite occurred for more posterior positions. In regards to the meniscal bearing, rotations were small and followed approximately the same patterns of the ankle rotations, accounted for the full conformity of the articulating surfaces. Translations in A/P were larger than in other directions, the bearing moving backward in plantarflexion and forward in dorsiflexion with respect to both components. It was observed that the closer to NR the position of the tibial component is, the larger this A/P motion is, accounted mainly to the associated larger range of flexion. The change of CaFiL and TiCaL effective length fraction over the flexion arc was found smaller than 0.1 in three specimens, smaller than 0.2 in the fourth, larger both in more anterior and more posterior locations of the tibial component. The simulated malpositioning did not affect much position and orientation of the mean helical axis in both the transversal and frontal planes.

The experimental protocol and measurements were appropriate to achieve the proposed goals. All kinematics variables support the conclusion that the ankle replaced with this original prosthesis behaves as predicted by the relevant computer models, i.e. physiological joint motion and ligament tension is experienced resulting in a considerable A/P motion of the meniscal bearing. These observations are particularly true in the NR postion for the prosthesis, but are somehow correct also in most of the tibial malpositions analysed, in particular those on the back.

A linkage-based mathematical model was used to design a ligament-compatible prosthesis to keep certain ligament fibres isometric during passive motion. The sagittal plane talar component radius is about 50% longer than that of the normal talus, the tibial component is spherically convex. A fully conforming meniscal bearing is interposed between them. Experiments in cadaver specimens confirmed the mathematical prediction that the bearing moves forwards on both metal components during dorsi-flexion and backwards during plantar flexion.

Between July 2003 and July 2008, the prosthesis was implanted into 250 patients at nine hospitals in Northern Italy. By November 2007, 158 in 156 patients were seen at least six months post-operatively. Mean age was 60.5 years. The diagnosis was post-traumatic osteoarthritis in 127, primary osteoarthritis in 17, rheumatoid arthritis in 10.

The mean follow-up was 32.5 months. The pre-operative AOFAS score of 36.2 rose to 75.9, 79.3, 77.9, and 79.0 respectively at 12, 24, 36, 48 months. Dorsi-flexion increased from 0.1° to 9.7°, plantarflexion from 15.1° to 24.6°. In 30 patients at one hospital, the range of postoperative motion, 14° – 53°, was significantly correlated to the range of bearing movement on the tibial component, 2mm–11mm, measured radiologically, (r2 = 0.37, p < 0.0005).

By December 2007, 2 revision operations had been performed at 24 months, one for unexplained pain not relieved by a successful arthrodesis, one in a patient with Charcot-Marie-Tooth disease. There were no device-related revisions (loosening, fracture, dislocation). The Kaplan-Meier survival rate (component-removal as end-point) at 4 years was 96% (Confidence interval 90–100%).

Early clinical results have demonstrated safety and efficacy. The survival rate at four years compares well with multi-centre 5-year rates published by the Swedish (531 cases, survival 78%), Norwegian (257, 89%) and New Zealand (202, 86%) registries.

The aim of this study is to present guidelines for treatment of acquired adult flat foot (AAFF) and review the results of a series of patients consecutively treated. 180 patients (215 feet), mean age 54? 12 years affected by AAFF were evaluated clinically, radiographically and by MRI to chose the adequate surgical strategy. Tibialis posterior dysfunctions grade 1 were treated by tenolysis and tendon repair (48 cases), grade 2 by removal of degenerated tissue and tendon augmentation (41 cases), grade 3 by flexor digitorum longus tendon transfer (23 cases); in these cases subtalar pronation without arthritis was corrected by addictional procedures consisting of either calcaneal osteotomy (66 cases), subtalar athroereisis (25 cases) or Evans procedure (21 cases) in case of severe midfoot abduction. Subtalar arthrodesis (82 cases) or triple arthrodesis (21 cases) were performed in case of subtalar arthritis isolated or associated with midtarsal arthritis respectively. Postoperatively plastercast without weight-bearing for 4 weeks followed by walking boot for 4 weeks was advised. All patients were followed up to 5 years. Before surgery the mean AOFAS score was 48+\−11, while it was 89+\−10 at follow-up (p< 0.005). Mean heel valgus deviation at rest was 15°+\−5° preoperatively and 8°+\−4° at follow-up (p< 0.005). Mean angulation of Meary’s line at talonavicular joint level was 165°+\−12° preoperatively and 175°+\6 at follow-up. Surgical strategy in AAFF should include adequate treatment of tibialis posterior disfunction and osteotomies for correction of the skeletal deformities if joints are arthritis free; arthrodesis should be considered in case of severe joint degeneration

A new design of total ankle replacement was developed. According to extensive prior research, the design features a spherical convex tibial component, a talar component with radius of curvature in the sagittal plane longer than that of the natural talus, and a meniscal component fully conforming to these two. The shapes of the tibial and talar components are compatible with a physiologic ankle mobility and with the natural role of the ligaments.

Within an eight-centre clinical trial, 114 patients were implanted in the period July 2003 – September 2006, with mean age 62.2 years (range 29 – 82). The AOFAS clinical score systems and standard radiographic assessment were used to assess patient outcome, here reported only for those 75 patients with follow-up longer than 6 months.

Intra-operatively, the components maintained complete congruence at the two articulating surfaces of the meniscal bearing over the entire motion arc, associated to a considerable anterior motion in dorsiflexion and posterior motion in plantarflexion of the meniscal-bearing, as predicted by the previous mathematical models. Mean 10.0 and 23.5 degrees respectively of dorsi- and plantar-flexion were measured immediately after implantation, for a mean additional range of motion of 19.2, which was maintained at follow-ups. Radiographs showed good alignment and no signs of evolutive radiolucency or loosening. The mean AOFAS score went from 40.8 pre-op to 66.2, 74.6 and 77.2 respectively at 3, 6 and 12 month follow-ups. One revision only was performed successfully three days after implantation because of a technical error.

In the score system utilized, Function and RoM sections scored better than any average previous total ankle result, Pain scored similarly. The satisfactory though preliminary observations from this novel design encourage continuation of the implantation, which is now extended over a few European countries. Instrumented gait and three-dimensional fluoroscopic analyses are in progress to quantify functional progresses.

INTRODUCTION Metal-on-metal hip resurfacing (MOMHR) has recently been reintroduced as a viable treatment option for young active patients. A short femoral neck and insufficient head are common deformities following CDH, Perthes disease and SFCE. Therefore, severity of these deformities is a contraindication for MOMHR, as contact between the femoral resurfacing component and the femoral head would be inadequate and off-set insufficient.

METHODS 32 patients with severe deformity of the hip were treated with Birmingham hip resurfacing and head lengthening. We used a standard acetabular component in 18 patients and a CDH acetabular component and supplementary screw fixation in 14. Bone chips produced while reaming the acetabulum were impacted on the femoral head to achieve the desired length, as evaluated on pre-op x-rays. Rehabilitation included no weight-bearing for 1 month and partial weight-bearing for another month.

RESULTS Median patient age was 44 years. Median head lengthening was 1.2 cm. Minimum follow-up was 3.1 years, maximum 5.2. Mean Harris Hip Score was 98. At follow-up 82% of the patients were involved in heavy or moderately heavy work. 34% of the patients practiced sports. Co and Cr serum concentrations at 25 months were respectively ng/ml 1.76, and 0.75. DXA analysis of the proximal femur showed complete recovery of BMD in Gruen zone 1 and increased in zone 7 (p= 0.05). There were no major complications.

DISCUSSION AND CONCLUSIONS The absence of major complications and the quality of our results support this technique in young active patients with severe deformity of the hip.

INTRODUCTION: Distal metatarsal osteotomies have been described for surgical treatment of hallux valgus with good results. The aim of this study is to review the results of our first 1000 consecutive hallux valgus cases treated by minimally invasive distal metatarsal osteotomy, SERI (Simple Effective Rapid Inexpensive).

MATERIAL AND METHODS: 1000 feet in 641 patients (359 bilateral), aged between 20 and 65 years (mean 49) affected by hallux valgus without arthritis were studied. Inclusion criteria were deformity less than 40° and intermetatarsal angle up to 18°. A 1-cm medial incision at the metatarsal neck, and a complete osteotomy were performed using an oscillating saw. With the naked eye all characteristics of the deformity were corrected by displacement of the metatarsal head (HVA, IMA, PASA, dorsal or plantar displacement). The osteotomy was stabilized by a 2-mm Kirschner wire. Immediate weight bearing was allowed with gauze bandage and talus shoes for 4 weeks. All patients were checked at an average follow-up of 37 months.

RESULTS: All osteotomies healed, delayed consolidation was observed in 25 feet. Slight stiffness was observed in 31 feet. Mean AOFAS score was 48+15 pre-op and 89+13 at follow up. The pre-op HVA was 32+8, while at follow-up it was 18+8 (p< 0.005), pre-op IMA was 14+3, while at follow-up it was 6+4 (p< 0.005), the pre-op PASA was 21+9, while at follow-up was 9+8(p< 0.005).

DISCUSSION AND CONCLUSION: SERI osteotomy was simple, effective, rapid and inexpensive in correcting hallux valgus deformity. Clinical and radiographical findings showed an adequate correction of the deformity.

INTRODUCTION: This prospective randomized study investigated short-term outcomes of cemented vs. HA-coated hip arthroplasty in elderly osteoporotic patients with femoral neck fractures.

METHODS: Forty consecutive patients with femoral neck fractures (AO/OTA fracture type B2 and B3) were randomized to receive either an AHS prosthesis (Group A, n = 22, cemented implant) or a Furlong prosthesis (Group B, n = 18, HA-coated implant). Inclusion criteria were: female age ≥75, fracture resulting from minor trauma, ability to communicate and bone mineral density (BMD) T-score at the contralateral hip lower than −2.5 SD. Subjective assessment was evaluated according to a rating system 0-(unsatisfactory) to 10(satisfactory). Average follow-up was 29 months for Group A and 27 months for Group B.

RESULTS: Average patient age was 75 ± 5 in both groups. There were no differences in ASA scores between the two groups. Surgical time was 77 ± 12 minutes for Group A, and 72 ± 13 minutes for Group B (ns). Harris hip score was 46 ± 36 in Group A and 62 ± 33 in Group B. (p < 0.05). SF-36 was 35 ± 32 in Group A and 54 ± 32 in Group B (ns). Subjective assessment was 5 ± 4 in Group A and 7 ± 3 in Group B (ns). The incidence of death during the follow-up period was 33% in Group A and 15% in Group B. (p < 0.05). One Group A patient underwent revision due to implant loosening. A Furlong prosthesis was successfully implanted in this patient.

DISCUSSION: Although femoral neck fractures in elderly osteoporotic patients are usually treated with cemented arthroplasty, our comparative study showed better results with the Furlong prosthesis, even if statistical significance was reached in only two parameters. The outcomes obtained with the Furlong prosthesis are due to the ability of the HA-coating to bind with osteoporotic bone, thus establishing a stable fixation. Fixation failed in only one cemented implant, but our case number was limited and the follow-up short. Post-op mortality at the time of follow-up was high. This was not unexpected, given the age level and health status of the study groups. This study shows that the HA-coated Furlong prosthesis is a viable option for the treatment of elderly osteoporotic femoral neck fracture patients.