Abstract
The scope of this thesis was to describe the design and development of the Dynamic Locking Blade Plate (DLBP), an improved internal fixation (IF) device for intracapsular hip fractures. This thesis focuses on intracapsular hip fractures since the results of current surgical treatment of this type of hip fracture are
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disappointing and give rise to much controversy. The rate of revision surgery following arthroplasty for a displaced intracapsular hip fracture varies between 0% and 24%. The rate of revision surgery following an IF technique varies between 14% and 53%. The results following arthroplasty are at the expense of an increased length of surgery, more operative blood loss and need for blood transfusion, a higher risk of deep wound infections, and possibly an increased mortality. The two main complications of IF are avascular necrosis and non-union. Chapter 2 describes a cohort of 34 relatively fit elderly (60-90 years) patients with a displaced intracapsular hip fracture treated by IF with a dynamic hip screw (DHS). After 7 years of follow-up, failure of fixation was observed in 13 out of 34 patients. In patients with successful bone healing the functional outcome was fair and did not worsen in the 7 years thereafter. In Chapter 3 a retrospective analysis of a small group of patients (11 women and 10 men) with an intracapsular hip fracture (10 undisplaced and 11 displaced) treated by IF with a Twin hook is reported. The mean age of the studied patient group was 59 years (43-75 years). After a mean follow-up of 13 months 3 out of 21 patients suffered a failure of fixation. Clinical outcome, assessed with the Harris Hip Score (HHS), was good. Chapter 4 The objective of the study described in chapter 4 is to determine the biomechanical characteristics of the DLBP and compare them to the characteristics of the Sliding Hip Screw (SHS) and Twin hook. The implants were inserted in a solid polyurethane foam (Sawbone) which functioned as a bone substitute. We tested rotational stability, which is of particular importance in femoral neck fractures, and cut out resistance. The results of the torsion tests of the DLBP revealed a three times higher rotational resistance when compared to the SHS and two times higher when compared to the Twin hook. There was no major difference in cut out resistance. The superior rotational stability of the DLBP and its minimal invasive characteristics may provide the right conditions for an uncomplicated bone healing of the femoral neck. In Chapter 5 the first clinical results of the DLBP are presented. IF with the DLBP was performed in 25 consecutive patients with an intracapsular hip fracture. Eight patients suffered an undisplaced hip fracture and 17 patients suffered a displaced hip fracture. After a 2 year follow-up uncomplicated bone healing was observed in 23 out 25 patients. Functional results assessed by the HHS were excellent. When compared to the international literature, these initial clinical results are very promising. In Chapter 6 the results described in this thesis are reflected upon
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