Preliminary experience with an image-free handheld robot for total knee arthroplasty: 77 cases compared with a matched control group.

BACKGROUND: Achieving an optimal limb alignment is an important factor affecting the long-term survival of total knee arthroplasty (TKA). This is the first study to look at the limb alignment and orientation of components in TKA using a novel image-free handheld robotic sculpting system. METHODS: This case-controlled study retrospectively compared limb and component alignment of 77 TKAs performed with a robot (Robot-group) with a matched control group of patients who received conventional alignment with intramedular rods (Control group). Alignment and component positioning was measured on full-leg weight-bearing and standard lateral X-rays by two independent observers. The image-free handheld robotic sculpting system calculated the planned and achieved mechanical axis (MA). Outliers were defined as > 3° deviation from planned alignment. RESULTS: Mean MA was 180.1° (SD = 1.9) in the Robot-group, compared to the Control group with a mean MA of 179.1° (SD = 3.1, p = 0.028). We observed 5 outliers (6%) in the Robot-group and 14 outliers (18%, p = 0.051) in the Control group. Fraction of outliers of the frontal tibial component was 0% in the Robot-group versus 8% in the Control group (p = 0.038). There were no other statistical differences regarding the implant positioning between both groups. CONCLUSION: The Robot-group showed significantly less outliers compared to the conventional technique. Whether these differences are clinically relevant is questionable and should be investigated on the long term. Randomized controlled trials with larger patient series will be needed in the future to confirm our preliminary results.

Injuries in male versus female soccer players: epidemiology of a nationwide study.

The aim of this study is to analyse soccer injuries on a national scale over one decade and to compare injury rates by gender. Detailed injury data obtained from the Royal Belgian Football Association from seasons 1999-2000 and 2009-2010 were recorded and gender differences in incidences of injuries, type of injury, affected body part and timing of injury were compared. A significant decrease in injuries from 7.56 to 5.96 injuries per 100 players was seen (p<0.0001). Overall male players sustained more cont usions, fractures, joint dislocations and musculotendinous injuries than female players. Proportionally, females sustained more severe injuries than men (p<0.0001). Significantly more injuries where sustained during competition in both males and females. The number of injuries in male and female soccer players has decreased over the past decade. A higher injury rate was seen in men but proportionally, females sustained more severe injuries.

Femoral component loosening in high-flexion total knee replacement: an in vitro comparison of high-flexion versus conventional designs.

High-flexion total knee replacement (TKR) designs have been introduced to improve flexion after TKR. Although the early results of such designs were promising, recent literature has raised concerns about the incidence of early loosening of the femoral component. We compared the minimum force required to cause femoral component loosening for six high-flexion and six conventional TKR designs in a laboratory experiment. Each TKR design was implanted in a femoral bone model and placed in a loading frame in 135° of flexion. Loosening of the femoral component was induced by moving the tibial component at a constant rate of displacement while maintaining the same angle of flexion. A stereophotogrammetric system registered the relative movement between the femoral component and the underlying bone until loosening occurred. Compared with high-flexion designs, conventional TKR designs required a significantly higher force before loosening occurred (p < 0.001). High-flexion designs with closed box geometry required significantly higher loosening forces than high-flexion designs with open box geometry (p = 0.0478). The presence of pegs further contributed to the fixation strength of components. We conclude that high-flexion designs have a greater risk for femoral component loosening than conventional TKR designs. We believe this is attributable to the absence of femoral load sharing between the prosthetic component and the condylar bone during flexion.

Liver tuberculosis mistaken for malignancy. The role of needle biopsy.

Despite advances in imaging techniques rare or atypical liver lesions still pose a diagnostic challenge. In many centres percutaneous fine needle aspiration cytology or biopsy is routinely performed in order to obtain a definitive diagnosis. However because of the risk of tumour seeding along the needle tract this attitude may jeopardize the patient's chances for cure in case of malignancy. The role of percutaneous liver biopsy is reappraised in the light of an observation in which major hepatectomy was performed for suspected neoplasia only to discover at pathology that the lesion was a benign tuberculosis pseudotumour.