Unicompartmental knee arthroplasty: all-poly versus metal-backed tibial component-a long-term follow-up study

INTRODUCTION

While considered a satisfactory solution, unicompartmental knee arthroplasty (UKA) still raises concerns in regard to its durability. These concerns particularly focus on the tibial component. This study aims to compare two different cemented tibial components belonging to the same UKA design: all polyethylene (AP) versus metal backed (MB), at a long-term follow-up.

MATERIALS AND METHODS

We retrospectively reviewed 143 successive patients, 83 of which underwent surgery with AP tibial component UKA (37 males, 46 females), and 67 with MB ones (17 males, 50 females). All implants had the same prosthetic design (Accuris UKA, Smith e Nephew) with identical femoral oxinium component but different tibial component, AP or MB. The KSS and KOOS were assessed at a mean of 11.5-year follow-up and compared to pre-operative, post-operative, and one year evaluation. Statistical analysis was performed with SPSS for Mac (version 17.0). To assess potential statistically significant differences, t test was used and significance was set at P < 0.05.

RESULTS

Final KSS at a mean of 11.5-year follow-up was 94.27 for the AP group and 96.12 for the MB ones. The final KOOS was 87 for AP components and 89.67 for the MB group. These results demonstrated, in all cases, statistically significant better results for MB tibial components compared to AP regarding KSS (P = 0.048), KOOS (P = 0.000), and pain (P = 0.014) at the 11.5-year follow-up. Survivorship for AP tibial component implants was 97.6%, while it was 89.5% for MB ones.

CONCLUSION

While the survivorship rate has been found to be greater for AP implants compared to MB tibial components, this study reveals statistically better functional results according to KSS and KOOS, and pain, at a long-term follow-up for MB implants.

A comparison of dynamic rotational knee instability between anatomic single-bundle and over-the-top anterior cruciate ligament reconstruction using triaxial accelerometry

PURPOSE

Recently, single-bundle (SB) anterior cruciate ligament (ACL) reconstruction has been advanced by the anatomic concept, but the biomechanical outcome of the anatomic method has not been fully investigated, especially for rotational instability. Anatomic SB and the single over-the-top procedures are the treatment of choice for primary cases and revision or skeletally immature cases, respectively. The purpose of this study was to investigate the dynamic rotational instability of anatomic SB and over-the-top reconstruction during a pivot shift test using triaxial accelerometry.

METHODS

Eight fresh frozen human cadaveric knees were used in this study. Rotational instability measurement was conducted during a pivot shift test by the use of a triaxial accelerometer attached to the tibia. The tests were performed in the ACL-intact, ACL-deficient and ACL-reconstructed knees with two different procedures (anatomic SB and over-the-top). The acceleration in three directions and the magnitude of acceleration were measured to evaluate rotational instability and compare between four different knee states.

RESULTS

The overall magnitude of acceleration was significantly different (P < 0.01) between the ACL-intact knees and the ACL-deficient knees. Both anatomic SB and over-the-top ACL reconstruction significantly reduced the overall magnitude of acceleration compared to the ACL-deficient knees, but still had larger accelerations compared to the ACL-intact knees. There was no significant difference for the overall magnitude of acceleration between anatomic SB and over-the-top reconstruction procedure.

CONCLUSION

Over-the-top reconstruction provides comparable result to anatomic SB reconstruction in terms of controlling the dynamic rotational stability. Over-the-top reconstruction might be one of the options for revision cases and in skeletally immature patients.

Use of transtibial aimer via the accessory anteromedial portal to identify the center of the ACL footprint

PURPOSE

To assess the ability of a transtibial aimer with a 7-mm off-set in a standardized position to reach the center of the ACL footprint on the femur through the AM portal.

METHODS

Nineteen cadaveric knees were dissected, and the perimeter of the femoral ACL footprint was marked. The aimer was placed just superior to the medial joint line close to the medial condyle through the AM portal. The guide was rested upon the posterior cortex and placed in three different positions: (A) at zero degrees in frontal plane and 60° in axial plane, (B) at 45° in frontal and 45° in axial, and (C) at the center of the ACL insertion site under direct visualization. A digital camera was used to take pictures on the axial plane, and Image J software was used for angle measurement. Aluminum beads were used to mark the three positions indicated by the aimer, and CT scans were performed. The distances from the true center of the ACL to each point were determined.

RESULTS

Position A resulted in femoral tunnel placement furthest from the center of the ACL footprint (8.6 mm). Position B was at a distance of 3.2 mm, and position C was the most accurate, with an average distance of 2.0 mm. The angles required by Position C varied with an average of 54° ± 11° in the frontal plane and an average of 44° ± 6° in the axial plane.

CONCLUSION

The 7-mm transtibial aimer was unable to reach the center of ACL footprint at a fixed orientation.

Hepatitis C virus among health care workers

The purpose of our study was to describe the results of a seroprevalence survey for HCV antibody among health care workers at our center. 961 specimens were consecutively obtained under code and screened for anti-HCV by the second generation immunoblot assay (RIBA 2) and hepatitis B core antibody by CORAB test. After serum samples were tested, we reviewed demographic data and categorized four groups: intravenous drug abusers (IVDAs), blood recipients, health care workers and apparently healthy subjects. 51/97 (52.6%) IVDAs, 8/77 (10.4%) transfusion recipients, 12/472 (2.5%) health care workers and 8/285 (2.8%) apparently healthy subjects were anti-HCV positive. Furthermore dividing health care personnel by type of profession we found that surgeons have a higher seroprevalence (4.3%) compared to other professions. Therefore severe preventive standards are required for health care workers.

Hepatitis C virus infection in family members of chronic carriers

To determine the transmission of hepatitis C in family members of chronic carriers we study the results of a HCV seroprevalence among spouses and children living together with patients affected by HCV related chronic liver disease. Seroprevalence of HCV antibodies and mean cohabitation time was determined among 54 index patients, their 54 spouses and 99 children. Twelve spouses (22.2%) and no children were anti-HCV positive, with an overall seroprevalence of 7.8%. Couples with both anti-HCV positive partners had a mean cohabitation time (31.8 +/- 10.4 years) higher compared to couples with only one anti-HCV positive partner (24.6 +/- 9.9 years) and children (19.1 +/- 10.2 years). Sexual transmission of HCV infection cannot be excluded and its prevalence is strongly associated to the length of cohabitation time.

Hepatitis C virus in prisoners

The purpose of this study was to assess the epidemiology of hepatitis C virus (HCV) in prisoners and outpatients attending our center. 2205 specimens were consecutively obtained under code and screened for anti-HCV by the second generation RIBA test and Hepatitis B core antibody (HBcAb) by CORAB test. After serum samples were tested, we reviewed demographic data and categorized four groups: Intravenous drug abusers (IVDAs), prisoners and apparently healthy subjects and warders. Anti-HCV prevalence was 59.4% in 613 IVDAs, 15.5% in 756 prisoners, 2.6% in 454 healthy subjects and 2.8% in 145 warders. These findings suggest that prisoners may be considered a group at increased risk for HCV infection.

[HCV and HBV infection in 3 communities in the Neapolitan area]

Using the antibody to HCV and HBc (anti-HCV, anti-HBc), we studied the prevalence of Hepatitis C and B virus in three groups: intravenous drug abusers, subjects lodging in huts and elderly clergymen. Statistical analysis was carried out by chi-square and Fisher's exact tests. Our results show statistical significance for anti-HCV seroprevalence among the three groups, while anti-HBc doesn't differ. These preliminary data seem to show that the two viruses have different ways of transmission.

Seroprevalence of HBV and HCV markers among intravenous drug abusers and subjects affected by chronic active hepatitis

In order to investigate the seroprevalence of HBV and HCV in neapolitan area, we studied blood specimens of 180 IVDAs, 115 CAH patients and 72 healthy subjects using hepatitis B core (anti-HBs) and hepatitis C antibody (anti-HCV). High frequency of anti-HBs (80.9%) and strong association with an unexpected seroprevalence of anti-HCV (67%) was found in CAH patients. Our study does not explain these results, but suggest either a possible inference between both viruses or that serum from CAH subjects contains a component that gives false positivity.