Abstract
Because of the decreased holding power of the screws, fixation of osteoporotic fractures has a high failure rate (10%–25%). It should also be reported that even if fixation does not fail, several osteoporotic patients with fractures have unsatisfactory functional results due to bony malunion.
Elderly patients with osteoporosis demand better fixation techniques. Treatment goals in this particular patient population include: proper fracture alignment, stable fixation and early rehabilitation. A surgeon should adopt a minimally-invasive technique in order to relieve the patient of physiological stress and allow for full-weight bearing of the fractured limb. Several fixation augmentation techniques have been proposed such as the use of PMMA, calcium phosphate cement, oblique screw insertion and cannulated ported screws.
Our studies indicated that osteoporotic bone fixation can be greatly improved by using implants coated with calcium phosphates such as hydroxyapatite. Hip fractures are the most severe form of fracture in patients with osteoporosis. Cut-out of the load-bearing implant is seen more frequently compared to patients with good bone quality often leading to revision surgery. We compared dynamic hip screw (DHS) fixation with hydroxyapatite(HA)-coated AO/ASIF screws to DHS fixation with standard AO/ASIF screws in osteoporotic trochanteric fractures. One-hundred-andtwenty patients were divided into two groups and randomized to receive 135° 4-hole DHS with either standard lag and cortical AO/ASIF screws (Group A) or HA-coated lag and cortical AO/ASIF screws (Group B). Inclusion criteria were: female, age > 65 years, AO/OTA fracture type A1 or A2 and a bone mass density (BMD) T-score lower than −2.5. Exclusion criteria included lag screw extension into the proximal third of the femoral head. Between the two groups, there were no differences in patient age, BMD, screw position in the femoral head, tip apex distance, quality of reduction and fracture impaction at the 6-month follow-up. In Group A, femoral neck shaft angle (FNSA) reduced over time (134 ± 5° postoperative vs. 126 ± 12° at 6 months, p = 0.003), whereas in Group B, no reduction occurred over time, as indicated by the lack of difference between the FNSA post-operative (134 ± 7°) and at 6 months (133 ± 7°). Lag screw cut-out occurred in four Group A cases but not in Group B (p < 0.05, = 0.8). Three patients with cases of cut-out underwent revision with bipolar prostheses. At 6 months, the Harris hip score was 60 ± 25 (Group A) and 71 ± 18 (Group B) (p= 0.007).
External fixation could be a viable treatment option in elderly trochanteric fracture patients since it typically involves a low energy trauma. However post-operative complications associated with inadequate pin fixation have limited its use. Because of the development of HA-coated screws, we compared external fixation with HA-coated screws (H-CP) to DHS with AO/ASIF stainless-steel screws in osteoporotic trochanteric fractures. Forty patients were divided into two groups and randomized for treatment with either 135° 4-hole DHS (Group A) or external fixation with 4 H-CP (Group B). Inclusion criteria were: female, age > 65 years, AO/OTA fracture type A1–2 and a BMD T-score lower than −2.5. All fixators were removed at 3 months. There were no differences in patient age, fracture type, BMD, ASA, hospital stay and quality of reduction. Average number of blood transfusions was 2 ± 0.1 in Group A, whereas no blood transfusions were required in Group B (p < 0.005). Post-operative FNSA was 134 ± 6 ° in Group A and 132 ± 4° in Group B (ns). In Group A, the varus collapse of the fracture at 6 months was 6 ± 8° and in Group B 2 ± 1° (p = 0.002). The Harris hip score was 62 ± 20 in Group A and 63 ± 17 in Group B (ns). In Group B, no screw infection occurred.
Conclusion: A valuable strategy that will benefit the elderly osteoporotic patient and provide for early mobilization is the use of a minimally-invasive technique, a well-restored anatomy of the fractured limb, no blood transfusion requirements and early rehabilitation. These should also be beneficial for maintaining the overall well-being of the patient. Our results demonstrate that enhanced screw osteointegration and fracture fixation will have a positive impact on the quality of life in the elderly osteoporotic patient.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
