The clinical outcome of total knee arthroplasty is compromised by a previously implanted medial unicondylar knee arthroplasty.

OBJECTIVE: To investigate the clinical outcome of patients that underwent conversion of a medial unicondylar knee arthroplasty (UKA) to a total knee arthroplasty (TKA) and to compare that outcome to patients that underwent primary TKA. It was hypothesized that those groups would significantly differ in terms of knee score outcome and implant survival. METHODS: A retrospective-comparative study was conducted utilizing data from the Federal state's arthroplasty registry. Included were patients from our department that undergone a conversion of a medial UKA to a TKA (UKA-TKA group). The Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) from preoperative and 1-year postoperative was used. Moreover, the implant survival was analyzed. RESULTS: In the UKA-TKA group, there were 51 cases (age 67 ± 10, 74% women), and in the TKA group, there were 2247 cases (age 69 ± 9, 66% women). The one-year postoperative WOMAC total score was 33 in the UKA-TKA group und 21 in the TKA group (p < 0.001). Similarly, the WOMAC pain, WOMAC stiffness, and WOMAC function scores were significantly worse in the UKA-TKA. After 5 years, the survival rates were 82% and 95% (p = 0.001). The 10-years prosthesis survival was 74% and 91% in the UKA-TKA and TKA groups, respectively (p < 0.001). CONCLUSIONS: Based on our findings it is concluded that patients who received a TKA after UKA have inferior results than those that directly receive a TKA. This is true for both patient-reported knee outcome and prosthesis survival. Converting UKA to TKA should not be seen as an easy operation, but should rather be done by surgeons with considerable experience in both primary and revision knee arthroplasty.

Addition of in situ reduced amidinato-methylaluminium chloride to acetylenes.

Two ethylene-bridged methylaluminium amidinates and one aluminium amidinate containing three terminal trimethylstannyl-ethynyl groups interconnected by π-coordinated potassium ions were prepared in situ. The re-oxidation of the ethylene-bridged compound by iodine followed by further reduction using the same activation procedure demonstrated the versatility of the approach. The reactivity of an ethylene-bridged methylaluminum amidinate towards HCl was examined to demonstrate the building block concept. DFT calculations were performed to gain insight into the mechanism of the in situ activation of diphenylacetylene.

(2,6-Bis[(dimethylamino)methyl]-phenyl-N(2),C(1),N(6))diphenyltin(II) bromide monohydrate.

In the title compound, [Sn(C(6)H(5))(2)(C(12)H(19)N(2))]Br.H(2)O, the Sn(IV) atom lies on a twofold axis and is coordinated by a C and two N atoms from the 2,6-bis[(dimethylamino)methyl]phenyl ligand in a tridentate fashion and by two phenyl groups. The resulting geometry is intermediate between square pyramidal and trigonal bipyramidal, with three C atoms in equatorial and the two N atoms in axial positions. The main deformation from ideal trigonal-bipyramidal geometry is seen for the N-Sn-N angle [152.18 (7) degrees]. The Br(-) anion and the water solvate molecule are on an inversion centre and twofold axis, respectively. They form an infinite chain of Br.H-O-H.Br hydrogen bonds [Br.O 3.529 (2) A] without contributing to the primary coordination sphere of the Sn atom.