Kilian Rueckl

Comparison of Elution Characteristics and Compressive Strength of Biantibiotic-Loaded PMMA Bone Cement for Spacers: Copal® Spacem with Gentamicin and Vancomycin versus Palacos® R

Purpose Copal® spacem is a new PMMA bone cement for fabricating spacers. This study compares elution of gentamicin, elution of vancomycin, and compressive strength of Copal® spacem and of Palacos® R+G at different vancomycin loadings in the powder of the cements. We hypothesized that antibiotic elution of Copal® spacem is superior at comparable compressive strength. Methods Compression test specimens were fabricated using Copal® spacem manually loaded with 0.5 g gentamicin and additionally 2 g, 4 g, and 6 g of vancomycin per 40 g of cement powder (COP specimens) and using 0.5 g gentamicin premixed Palacos® R+G manually loaded with 2 g, 4 g, and 6 g of vancomycin per 40 g of cement powder (PAL specimens). These specimens were used for determination of gentamicin and vancomycin elution (in fetal calf serum, at 22°C) and for determination of compressive strength both prior and following the elution tests. Results Cumulative gentamicin concentrations (p < 0.005) and gentamicin concentration after 28 days (p ≤ 0.043) were significantly lower for COP specimens compared to PAL specimens. Cumulative vancomycin concentrations were significantly higher (p ≤ 0.043) for COP specimens after the second day. Vancomycin concentrations after 28 days were not significantly higher for the Copal specimens loaded with 2 g and 4 g of vancomycin. Compressive strength was not significantly different between COP specimens and PAL specimens before elution tests. Compressive strength after the elution tests was significantly lower (p = 0.005) for COP specimens loaded with 2 g of vancomycin. Conclusion We could not demonstrate consistent superior antibiotic elution from Copal® spacem compared to Palacos® R+G for fabricating gentamicin and vancomycin loaded spacers. The results do not favor Copal® spacem over Palacos® R+G for the use as a gentamicin and vancomycin biantibiotic-loaded spacer.

Fracture of an S-ROM stem at the sleeve-stem junction

Fracture of a well-ingrown femoral component is a rare and often challenging complication. Modular junctions and sleeve interfaces have been identified as one potential point of weakness with corrosion and fretting being contributing factors to ultimate femoral component fracture. Stem fractures at the sleeve interface were reported occasionally for the proximal ingrowth modular Emperion System (Smith and Nephew, Memphis, TN). However, this failure mechanism has been reported infrequently, often associated with corrosion at the modular junction, for the similarly designed S-ROM system (DePuy Orthopedics Inc., Warsaw, IN). We present the case of a 52-year-old patient, with a body weight of 84 kg (185 lbs) and a body mass index of 30.6 kg/m2, who suffered a fatigue fracture of a 14 × 09 × 130 mm S-ROM stem 42 months after implantation. The present study presents the results of the surface analysis, discusses possible failure mechanisms, provides treatment guidelines, and a review of the literature revealing 15 cases of failure at the level of the stem-sleeve junction. In particular, modifiable risk factors for potential stem failure, including stem diameter, stem offset, and the resulting cantilever bending forces on the proximal sleeve-stem junction, are discussed in detail.

Arthroskopische Therapie bei spinoglenoidalem Ganglion

Aims and Indications A paralabral ganglion cyst of the shoulder can cause neuropathy of the inferior branches of the suprascapular nerve. This can lead to atrophy of the infraspinatus muscle. Arthroscopic decompression of the cyst in combination with repair of the associated labrum tear appears to be an effective treatment option. Methods Initially the connection of the cyst to the joint in the area of the posterior rim of the glenoid is identified arthroscopically. Following the decompression of the cyst the labrum tear is repaired to avoid recurrence. The goal is the complete decompression of the ganglion cyst carefully protecting the infraspinatus branch. Concomitant intraarticular pathologies are also addressed. Conclusions In the literature arthroscopic treatment is superior to open surgical treatments. The degree of muscle atrophy at the time of surgery determines the prognosis for functional recovery. There is a lack of long-term outcome studies and publications of larger case series.

Sport nach Knie- und Hüftendoprothetik

The introduction of new materials and better implant coatings seems to provide the prerequisites for more intense physical activities after total joint arthroplasties of the lower extremity. Despite recent advances in implant design and materials, recommendations for sport after total joint arthroplasty have not been updated over the past 20 years. The introduction of modern uncemented fixation as well as highly cross-linked polyethylene into total hip arthroplasty allow for a more active life-style without an increased risk of loosening or complications. This publication reviews the literature and presents the current knowledge to provide guidelines for orthopaedic surgeons treating patients after total joint replacement surgery.