The advantages of computer navigated total knee replacement are well documented in the literature, however, increased surgical time and cost issues remain the major deterrent for the wide use of this technology. Placement of cutting jigs under computer guidance forms a major aspect of computer assisted knee replacement surgery. The use of a motorized mini-robotic cutting jig allows for a more precise and time efficient execution of the femoral cuts under computer guidance. We present a preliminary report on our experience using standard computer assisted surgery (CAS) jigs and mini robotic motorized jigs in computer navigated knee replacement

Introduction

There has been much controversy around metal on metal hip replacements of late due to adverse metal reactions. There is evidence implicating lymphocyte mediated response (type IV delayed-hypersensitivity) to metal debris generated by the implants as one of the main factors responsible for the reactions. Our understanding of these adverse reactions continues to improve but we also recognize that the majority of patients with MOM implants are asymptomatic with well functioning implants. Studies have shown up to 16% allergy to metal ions on pre-operative allergy patch testing. We set out to determine the incidence of hypersensitivity to Cobalt, Chromium and Molybdenum in a arthroplasty population.

Introduction

Maximizing efficiency in total knee replacement surgery is desirable and one of the key aspects is optimum utilization of available theatre time allocation. The level of complexity of the pathology is often one of the determinants of the length of operative time. Body mass index (BMI) has also been positively correlated with operative time. However, two patients with the same BMI but different body habitus (central obesity vs generalized obesity) may present different challenges during surgery. An index focusing on the anthropometry of the lower limb (supra-patella index SPI) has been proposed and we hypothesize that it correlates more closely with operative time than BMI.

Liquiband is a new tissue adhesive: It works like super glue – it is attached to the wound edges, it sets within seconds and lasts for about two weeks. The glue then flakes off automatically as the skin regenerates. There is no need for suture removal. A second step forms a waterproof layer over the wound. We compared in a prospective randomized trial the Liquiband glue to skin staples.

Over a 9 month period (May 2005 to January 2006) we enrolled a total of 80 patients, 40 in each group. The patients were booked for elective limb surgery and agreed to participate in the study. The surgical wounds were closed in layers. The skin was then either closed with Liquiband or skin staples. A follow up was a weeks 2, 6 and 18. The wound healing was photographically documented. The wounds were assessed according to the Hollander wound scoring system and a patient satisfaction score. Ethical approval was obtained.

The two groups were matched for sex, age, body-mass index and smoking. There was a similar total wound length in both groups. All wounds healed. In the Liquiband group 4 superficial infections occurred, one dehiscence due to glue removal by the patient. In the skin staples group we had 6 superficial infections. The patient satisfaction score was lower in the skin staple group (7.0 compared to 8.3 in the Liquiband group) and on the Hollander wound scoring system there were 10% more step-off borders and 12% more edge inversions in the skin staple group. The glue did not stain the skin or leave visible marks.

The authors conclude that the Liquiband skin glue is safe and effective for elective surgery. The Liquiband skin glue does not require staple removal after wound healing and the waterproof closure of the wound provides additional safety.