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In rotator cuff repair, strong and reliable suturing is necessary to decrease failure rates. The biomechanics of two self-cinching stitches – the single-loop knot stitch (SLKS) and the double-loop knot stitch (DLKS) – and the modified Mason-Allen stitch (mMAS) were compared. Twenty-seven porcine infraspinatus tendons were randomized among the three stitches. Each was cyclically loaded (10–80–200 N for 50 cycles each) while the gap formation was measured. Next, ultimate load to failure was tested. The gap widths after cyclic loading were 8.72 ± 0.93 mm for the DLKS, 8.65 ± 1.33 mm for the mMAS, and 9.14 ± 0.89 mm for the SLKS, without significant differences. The DLKS showed the highest ultimate load (350.52 ± 38.54 N) compared with the mMAS (320.88 ± 53.29 N; p = 0.304) and the SLKS (290.54 ± 60.51 N; p < 0.05). The DLKS showed similar reliability and better strength compared with the mMAS, while the SLKS showed a slight but not significant decrease in performance. In our experience, the DLKS and SLKS have clinical advantages, as they are easy to perform and the self-cinching loop knot allows the surgeon to grasp degenerative tendon tissue. Initial intraoperative tightening of the suture complex (preloading) before locking is important in order to decrease postoperative elongation.

Firstly, the way of implementing approximatively the initial rollback of the natural tibiofemoral joint (TFJ) in a total knee replacement (AEQUOS G1 TKR) is discussed. By configuration of the curvatures of the medial and lateral articulating surfaces a cam gear mechanism with positive drive can be installed, which works under force closure of the femoral and tibial surfaces. Briefly the geometric design features in flexion/extension are described and construction-conditioned kinematical and functional properties that arise are discussed. Due to a positive drive of the cam gear under the force closure during the stance phase of gait the articulating surfaces predominantly roll. As a result of rolling, a sliding friction is avoided, thus the resistance to motion is reduced during the stance phase. Secondly, in vivo fluoroscopic measurements of the patella tendon angle during flexion/extension are presented. The patella tendon angle/ knee flexion angle characteristic and the kinematic profile in trend were similar to those observed in the native knee during gait (0°-60°). [ABSTRACT FROM AUTHOR]

Importance: Costal cartilage calcification (CCC) of the cartilage graft, commonly used in reconstruction of nasal/auricular deformities, can cause poor surgical outcome, but structural and quantitative analyses are lacking. Objective: To compare the prevalence, amount, and structural pattern of CCC from individuals by gender and age, as measured by digital contact radiography. Design, Setting, and Participants: This is a cross-sectional cadaveric study ( n  = 92) of the seventh rib cartilage. CCC prevalence/amount/structural pattern (central [c]/peripheral [p]/diffuse [d]) was analyzed within three age groups: I (<40 years), II (40-70 years), and III (>70 years). Main Outcomes and Measures: Qualitative and quantitative CCC analyses were set in relation to gender/structural pattern/age. Results: CCC prevalence was gender independent (96.7%) and occurred in c/p/d: 12.4%/22.4%/65.2%. Structural CCC pattern differed between age groups (I: 80%; c/p/d: 26.7%/46.6%/6.7%; II: 100%; c/p/d: 18.0%/30.8%/51.2%; III: 100%; p/d: 2.6%/97.4%). The mean CCC amount (9.1%) was gender independent and showed a significant correlation with age ( p  = 0.001). The mean amount showed a significant difference between the structural pattern [d/p: 3.3 times higher ( p  = 0.006), d/c: 7.7 times higher ( p  < 0.001)] and age groups (I/II/III: 6.4/8.5%/10.9%), whereby the amount was higher in groups II (factor: 7.4; p  < 0.001) and III (factor: 16.5; p  < 0.001) compared with group I. Conclusions: These data show an age-/gender-independent high CCC prevalence in the general population (96.7%). CCC already occurred in young donors (<40 years) with a not negligible amount (6.4%). CCC increased with age and structural analysis showed a gender-/age-specific pattern, whereby males were prone to peripheral/females to central CCC. Diffuse CCC was observed as an age-independent sign for high CCC levels.

Porous structure properties are known to conduct initial and long-term stability of titanium alloy implants. This study aims to assess the histomorphometric effect of a 3-D porosity in Ti-6Al-4V implants (PI) on osseointegration in comparison to solid Ti-6Al-4V implants (SI). The PI was produced in a spaceholder method and sintering and has a pore size of mean 400 µm (50 µm to 500 µm) and mimics human trabecular bone. Pairs of PI and equal sized SI as reference were bilaterally implanted at random in the lateral femoral condyle of 16 Chinchilla-Bastard rabbits. The animals were sacrificed after 4 and 12 weeks for histomorphometric analysis. The histomorphometric evaluation confirmed a successful short-term osseohealing (4 weeks) and mid-term osseoremodeling (12 weeks) for both types of implants. The total newly formed bone area was larger for PI than for SI after 4 and 12 weeks, with the intraporous bone area being accountable for the significant difference (p<0.05). A more detailed observation of bone area distribution revealed a bony accumulation in a radius of +/- 500 µm around the implant surface after remodeling. The bone-to-implant contact (BIC) increased significantly (p<0.05) from 4 to 12 weeks (PI 26.23 % to 42.68 %; SI 28.44 % to 47.47 %) for both types of implants. Due to different surface properties, however, PI had a significant (p<0.05) larger absolute osseous contact (mm) to the implant circumference compared to the SI (4 weeks: 7.46 mm vs 5.72 mm; 12 weeks: 11.57 mm vs 9.52 mm [PI vs. SI]). The regional influences (trabecular vs. cortical) on bone formation and the intraporous distribution were also presented. Conclusively, the porous structure and surface properties of PI enable a successful and regular osseointegration and enhance the bony fixation compared to solid implants under experimental conditions.

In the present study, we analyzed the histological characteristics of osseointegration of an open-porous Ti-6Al-4V material that was produced in a space holder method creating a 3-D through-pores trabecular design that mimics the inhomogeneity and size relationships of trabecular bone in macro- as well as microstructure. Pairs of cylindrical implants with a porosity of 49 % and an average pore diameter of 400 µm (PI) or equal sized solid, corundum blasted devices (SI) as reference were bilaterally implanted press fit in the lateral condyles of 16 rabbits. Histological examination was performed after 4 weeks of short-term osseohealing and 12 weeks of mid-term osseoremodeling and we summarized the criteria for sequential osseointegration. After 4 weeks, osteoid had already been largely replaced by mineralized woven bone in both types of implants but was only represented to a greater extent in the deeper pores of PI. The cortical as well as trabecular region showed regular osseohealing with excessive and spatially undirected formation of immature woven bone. A dense bone mass was found in the cortical area, while in the trabecular region the bone mass was reduced distinctly, presenting large lacuna-like recesses and a demarcating trabecular structure. The pores near the implant surface contained more mineralized woven bone than the deeper pores. After 12 weeks, the osseoremodeling was largely completed with a physiological maturation to lamellar bone. The newly formed bone mass increased for PI and SI compared to the 4-week group and osteoid was only detectable in the deeper pores. The inhomogeneous trabecular design of the pores enables an excellent ingrowth of mineralized lamellar bone after remodeling to a pore depth of 1800 µm, which proves a functional load transfer from the surrounding bone into the implant. According to the concept of osseointegration by Branemark and Albrektsson, the histological evaluation confirms a successful, superior osseointegration of the presented porous properties improving long-term implant stability. The presented study protocol allows an excellent evaluation and comparison of the sequential osseointegration from short-term osseohealing to mid-term osseoremodeling.