Several studies explored the biological effects of low frequency low energy pulsed electromagnetic fields (PEMFs, Igea Biophysics Laboratory, Carpi, Italy) on human body reporting different functional changes. In the orthopedic field, PEMFs have been shown to be effective in enhancing endogenous bone and osteochondral repair, incrementing bone mineral density, accelerating the process of osteogenic differentiation and limiting cartilage damage. Much research activity has focused on the mechanisms of interaction between PEMFs and membrane receptors such as adenosine receptors (ARs). In particular, PEMF exposure mediates a significant upregulation of A_2A and A₃ARs expressed in various cells or tissues involving a reduction of most of the pro-inflammatory cytokines. In tissue engineering for cartilage repair a double role for PEMFs could be hypothesized: in vitro by stimulating cell proliferation, colonization of the scaffold and production of tissue matrix; in vivo after surgical implantation of the construct by favoring the anabolic activities of the implanted cells and surrounding tissues and protecting the construct from the catabolic effects of inflammation. Of particular interest is the observation that PEMFs, through the increase of ARs, enhance the working efficiency of the endogenous modulator adenosine, producing a more physiological effect than the use of exogenous drugs. This observation suggests the hypothesis that PEMFs could be considered a non-invasive treatment with a low impact on daily life. In conclusion, PEMFs represent an important approach in the pharmacological field providing excellent therapeutic results in various inflammatory diseases and in particular in the functional recovery of the damaged joint tissues.

We undertook a randomised controlled trial to compare bipolar hemiarthroplasty (HA) with a novel total hip replacement (THR) comprising a polycarbonate–urethane (PCU) acetabular component coupled with a large-diameter metal femoral head for the treatment of displaced fractures of the femoral neck in elderly patients. Functional outcome, assessed with the Harris hip score (HHS) at three months and then annually after surgery, was the primary endpoint. Rates of revision and complication were secondary endpoints.

Based on a power analysis, 96 consecutive patients aged > 70 years were randomised to receive either HA (49) or a PCU-THR (47). The mean follow-up was 30.1 months (23 to 50) and 28.6 months (22 to 52) for the HA and the PCU group, respectively.

The HHS showed no statistically significant difference between the groups at every follow-up. Higher pain was recorded in the PCU group at one and two years’ follow-up (p = 0.006 and p = 0.019, respectively). In the HA group no revision was performed. In the PCU-THR group six patients underwent revision and one patient is currently awaiting re-operation. The three-year survival rate of the PCU-THR group was 0.841 (95% confidence interval 0.680 to 0.926).

Based on our findings we do not recommend the use of the PCU acetabular component as part of the treatment of patients with fractures of the femoral neck.

Cite this article: Bone Joint J 2013;95-B:609–15.

Introduction

In elderly patients, the incidence of a second fracture in the contralateral hip within 2 years of a femoral neck fracture (FNF), ranges from 7 to 12%.

Introduction: In situ subtalar arthrodesis cannot restore anatomical shape of the hindfoot in severe flat foot deformities. Purpose of this paper is to evaluate the result of 250 feet consecutively operated by subtalar arthrodesis with distraction and insertion of a mini structural bone block (SAMBB).

Material and Methods: 178 patients (250 feet), mean age 55+/−11 years affected by acquired adult flat foot with subtalar arthritis were evaluated clinically and radiographically and selected to receive SAMBB.

Arthrodesis was performed through a 2.5 cm incision, with partial cartilage removal and insertion of a structural corticocancellous block (2 × 1cm), harvested from the proximal ipsilateral tibia, vertically positioned into the sinus tarsi. Associate procedures were Achilles tendon lengthening (124), SERI procedure (61), hind-foot deformity correction (32). Postoperatively plaster-cast without weight-bearing for 4 weeks followed by walking boot was advised. All patients were reviewed at a minimum follow-up of 5 years.

Results: Before surgery the mean AOFAS score was 42+/−15, while it was 90+/−8 at follow-up (p< 0.005). Mean heel valgus deviation at rest was 15°+/−8° preoperatively and 6°+/−5° at follow-up (p< 0.005). Mean angulation of Meary’s line at talonavicular joint level was 160°+/−11° preoperatively and 174°+/−8 at follow-up. No complications were found. No or minimal arthritis progression was observed in the ipsilateral foot joints at follow up.

Conclusions: SAMBB resulted in an adequate correction of the deformity, with restoration of the anatomical shape of the hind foot and correction of the relationship with the midtarsal joint with no need of hardware. Consequent reduced arthritis progression and excellent clinical result were obtained.

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

Introduction: Pin loosening is a common complication associated with external fixation. Various attempts such as coating the pins with calcium phosphates, have been made to modify the pin surface in order to reduce pin loosening and provide good fixation. Animal and clinical studies showed that fixation using tapered external fixation pins coated with hydroxyapatite is superior to standard pins. However, there is no data on cylindrical pins either fully or partially coated with HA. A partial coating could be a solution to optimize pin fixation with the advantage of easier removal compared to fully coated pins. Our purpose was to compare standard and partially coated cylindrical Apex pins implanted in a sheep model at 2 and 6 weeks. As controls we included fully coated tapered pins.

Materials/Methods: Five groups of pins were studied. Group A included standard cylindrical Apex pins implanted in sheep which were euthanized 2 weeks after surgery; Group B included partially coated Apex pins implanted in sheep which were euthanized 2 weeks after surgery; Group C included tapered pins fully coated with HA implanted in sheep which were euthanized 2 weeks after surgery; Group D included Standard Apex pins implanted in sheep which were euthanized 6 weeks after surgery; Group E included partially coated Apex pins implanted in sheep which were euthanized 6 weeks after surgery. With the tapered pins, full contact between the coated surface and both cortices was obtained. After pin implantation, a unilateral external fixator was mounted onto the pins (Stryker carbon blue monotube Ø 20/250mm). A 5mm long removal osteotomy was performed in the mid-part of the tibial diaphysis, so that 3 pins were situated above the gap and 3 below to ensure load transfer through the bone-pin interface. Extraction torque and tibial torque resistance and histological analyses were obtained after pin removal.

Results: At 2 weeks, mean insertion torque was significantly higher for group C compared to group A (p = 0.03). Mean extraction torque was statistically higher for group B compared to group A (p = 0.001). A statistically significant difference was found in the Pettine index (p = 0.03) between groups A and B. At 6 weeks, no differences in extraction torque were seen.

Discussion: We believe that the partial application of the coating reduced the potential for osteointegration and the ultimate fixation of the coated Apex pins.

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.