TY  - JOUR
A1  - Fuchs, Konrad F.
A1  - Heilig, Philipp
A1  - McDonogh, Miriam
A1  - Boelch, Sebastian
A1  - Gbureck, Uwe
A1  - Meffert, Rainer H.
A1  - Hoelscher-Doht, Stefanie
A1  - Jordan, Martin C.
T1  - Cement-augmented screw fixation for calcaneal fracture treatment: a biomechanical study comparing two injectable bone substitutes
JF  - Journal of Orthopaedic Surgery and Research
N2  - Background 
The role of cement-augmented screw fixation for calcaneal fracture treatment remains unclear. Therefore, this study was performed to biomechanically analyze screw osteosynthesis by reinforcement with either a calcium phosphate (CP)-based or polymethylmethacrylate (PMMA)-based injectable bone cement. 

Methods 
A calcaneal fracture (Sanders type IIA) including a central cancellous bone defect was generated in 27 synthetic bones, and the specimens were assigned to 3 groups. The first group was fixed with four screws (3.5 mm and 6.5 mm), the second group with screws and CP-based cement (Graftys (R) QuickSet; Graftys, Aix-en-Provence, France), and the third group with screws and PMMA-based cement (Traumacem (TM) V+; DePuy Synthes, Warsaw, IN, USA). Biomechanical testing was conducted to analyze peak-to-peak displacement, total displacement, and stiffness in following a standardized protocol. 

Results 
The peak-to-peak displacement under a 200-N load was not significantly different among the groups; however, peak-to-peak displacement under a 600- and 1000-N load as well as total displacement exhibited better stability in PMMA-augmented screw osteosynthesis compared to screw fixation without augmentation. The stiffness of the construct was increased by both CP- and PMMA-based cements. 

Conclusion 
Addition of an injectable bone cement to screw osteosynthesis is able to increase fixation strength in a biomechanical calcaneal fracture model with synthetic bones. In such cases, PMMA-based cements are more effective than CP-based cements because of their inherently higher compressive strength. However, whether this high strength is required in the clinical setting for early weight-bearing remains controversial, and the non-degradable properties of PMMA might cause difficulties during subsequent interventions in younger patients.
KW  - arthritis
KW  - bone
KW  - calcaneus
KW  - cement
KW  - fracture
KW  - fixation
KW  - osteoporosis
KW  - sanders
KW  - screw
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230336
VL  - 15
ER  - 
TY  - JOUR
A1  - Wirtz, Dieter C.
A1  - Gravius, Sascha
A1  - Ascherl, Rudolf
A1  - Thorweihe, Miguel
A1  - Forst, Raimund
A1  - Noeth, Ulrich
A1  - Maus, Uwe M.
A1  - Wimmer, Matthias D.
A1  - Zeiler, Guenther
A1  - Deml, Moritz C.
T1  - Uncemented femoral revision arthroplasty using a modular tapered, fluted titanium stem 5-to 16-year results of 163 cases
JF  - Acta Orthopaedica
N2  - Background and purpose - Due to the relative lack of reports on the medium- to long-term clinical and radiographic results of modular femoral cementless revision, we conducted this study to evaluate the medium- to long-term results of uncemented femoral stem revisions using the modular MRP-TITAN stem with distal diaphyseal fixation in a consecutive patient series. 
Patients and methods - We retrospectively analyzed 163 femoral stem revisions performed between 1993 and 2001 with a mean follow-up of 10 (5-16) years. Clinical assessment included the Harris hip score (HHS) with reference to comorbidities and femoral defect sizes classified by Charnley and Paprosky. Intraoperative and postoperative complications were analyzed and the failure rate of the MRP stem for any reason was examined. 
Results - Mean HHS improved up to the last follow-up (37 (SD 24) vs. 79 (SD 19); p < 0.001). 99 cases (61%) had extensive bone defects (Paprosky IIB-III). Radiographic evaluation showed stable stem anchorage in 151 cases (93%) at the last follow-up. 10 implants (6%) failed for various reasons. Neither a breakage of a stem nor loosening of the morse taper junction was recorded. Kaplan-Meier survival analysis revealed a 10-year survival probability of 97% (95% CI: 95-100). 
Interpretation - This is one of the largest medium- to longterm analyses of cementless modular revision stems with distal diaphyseal anchorage. The modular MRP-TITAN was reliable, with a Kaplan-Meier survival probability of 97% at 10 years.
KW  - follow-up
KW  - distal fixation
KW  - bone loss
KW  - replacement
KW  - register
KW  - junction
KW  - cement
KW  - prosthesis
KW  - roentgenographic assessment
KW  - total HIP-arthroplasty
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114555
SN  - 1745-3674
VL  - 85
IS  - 6
ER  -