Mincing cartilage with commercially available shavers is increasingly used for treating focal cartilage defects. This study aimed to compare the impact of mincing bovine articular cartilage using different shaver blades on chondrocyte viability.

Bovine articular cartilage was harvested using a scalpel or three different shaver blades (2.5 mm, 3.5 mm, or 4.2 mm) from a commercially available shaver. The cartilage obtained with a scalpel was minced into fragments smaller than 1 mm³. All four conditions were cultivated in a culture medium for seven days. After Day 1 and Day 7, metabolic activity, RNA isolation, and gene expression of anabolic (COL2A1, ACAN) and catabolic genes (MMP1, MMP13), Live/Dead staining and visualization using confocal microscopy, and flow cytometric characterization of minced cartilage chondrocytes were measured.

The study found that mincing cartilage with shavers significantly reduced metabolic activity after one and seven days compared to scalpel mincing (p<0.001). Gene expression of anabolic genes was reduced, while catabolic genes were increased after day 7 in all shaver conditions. The MMP13/COL2A1 ratio was also increased in all shaver conditions. Confocal microscopy revealed a thin line of dead cells at the lesion site with viable cells below for the scalpel mincing and a higher number of dead cells diffusely distributed in the shaver conditions. After seven days, there was a significant decrease in viable cells in the shaver conditions compared to scalpel mincing (p<0.05). Flow cytometric characterization revealed fewer intact cells and proportionally more dead cells in all shaver conditions compared to the scalpel mincing.

Mincing bovine articular cartilage with commercially available shavers reduces the viability of chondrocytes compared to scalpel mincing. This indicates that mincing cartilage with a shaver should be considered a matrix rather than a cell therapy. Further experimental and clinical studies are required to standardize the mincing process with a shaver.

Acknowledgements: This study received unrestricted funding from KARL STORZ SE & Co. KG.

Aims

The purpose of this study was to analyze the incidence of the different ultrasound phenotypes of developmental dysplasia of the hip (DDH), and to determine their subsequent course.

In recent years, the direct anterior approach (DAA) has become a standard approach for primary total hip arthroplasty (THA). With the increasing use of the DAA in primary cases also more and more revision surgeries are performed through the same interval. With ability to extend the DAA interval proximally and distally, loose cups, loose stems, and even periprosthetic femoral fractures (PPF) can be treated. Especially, PPF are devastating complications causing functional limitations and increased mortality. Therefore, we conducted a study to report the outcome of surgical treatment of PPF with the DAA interval.

We report on the one year complications and mortality in 40 cases with a mean clinical follow-up of 1.5 years. Mean age of patients was 74.3 years. Fractures were classified as Vancouver B2 (36), and B3 (N=4). In 14 cases, a standard stem was used, and in 26 cases a modular revision stem. In 30 cases, a distal extension +/- tensor release was used, in 4 cases a proximal tensor release was done, and in the remaining 6 cases revision could be performed without extension of the approach.

Median cut/suture time was 152 minutes (IQR 80 – 279). The overall complication rate in our patient group was 12.5%. 2 patients died in the first three months after operation. One patient had a transient femoral nerve palsy, which completely recovered.

The DAA interval to the hip for the treatment of PFF showed similar results compared with other approaches regarding mortality, complications, fracture healing, dislocation rate and clinical results. We conclude that femoral revision in case of PPF in the DAA interval is a safe and reliable procedure. Each Vancouver type of periprosthetic fracture can be treated by use of this approach.

We aimed to investigate the clinical consequences of intraoperative acetabular fractures. Between 2003 and 2012, a total of 3391 cementless total hip arthroplasties (THA) were performed at the Dept. of Orthopaedics, Innsbruck Medical University. Of those, a total of 160 patients underwent a CT scan within 30 days postoperatively. The scans of 44 patients were not suitable for analyse due to thick scan layers. Of the remaining 116 patients, 76 had a fracture. Reasons for CT-scans were suspected bleeding, hip pain, abdominal symptoms, etc.

The fractures included 59 isolated acetabular fractures, the rest of fractures was in the superior or inferior pubic ramus or the tuber ischiadicum.

Four cases out of the 59 acetabular fractures underwent revision surgery due to periprosthetic joint infection after 0, 2, 10 and 23 months. Four patients underwent revision due to cup loosening after 13 and 14 days as well as after 16 and 24 months. Of those, three showed a central acetabular fracture with protrusion.

In 33 of the remaining 51 patients, a minimum of 3 x-rays was available for migration analysis with EBRA. In 6 patients, the x-rays were not comparable to each other. The 27 remaining acetabular fractures were categorised according to AO classification in 62A1 (1; posterior wall), 62A2 (16; posterior column), 62A3 (6; anterior wall), and others (4). Four hips showed initial migration of more than 3 mm in the first 6 months. One had a central fracture, and was lost for follow-up after 8 months. Two had an anterior column fracture and showed no further migration after 6 months. One showed also a radiolucency of more than 2 mm in all 3 zones and was lost for follow-up.

We conclude that intraoperative acetabular fractures occur more often than we expected. Fractures of the acetabular ring involving one column do not seem to compromise the long-term stability of the implant. Central fractures required revision or showed loosening proved by high cup migration.