Randomized prospective study comparing tri-cortical iliac crest autograft to allograft in the lateral column lengthening component for operative correction of adult acquired flatfoot deformity

BACKGROUND: Operative treatment of stage II posterior tibial tendon insufficiency (PTTI) is controversial. Many soft-tissue and bony procedures and various combinations of the two have been reported for treatment of stage II PTTI. Orthopaedists recognize the lateral column lengthening component of the procedure as a successful reconstructive technique. The use of cortical allograft for lateral column lengthening in the correction of pes planus in the pediatric patient population has been routine. In the adult population, however, tricortical iliac crest autograft has been the bone graft of choice. Harvest of this autograft can precipitate significant morbidity and cost. Therefore, we undertook this randomized controlled trial to compare graft incorporation and healing of allograft and autograft in the lateral column lengthening component of adult flatfoot reconstruction. METHODS: Lateral column lengthening was done as a component of operative correction for stage II PTTI in adult patients (older than 18 years) by two surgeons using similar procedures. The patients were randomized to either the allograft or autograft procedures. The primary endpoint was graft incorporation and healing as assessed by radiographs. RESULTS: The study included 33 randomized feet in 31 patients. We followed 18 feet in the allograft group and 15 in the autograft group to the point of union. There were 21 women and 10 men. There were no delayed unions, nonunions, or hardware failures. All patients in both groups achieved bony union by the 12-week followup evaluation. Two superficial foot infections were successfully treated with oral antibiotics. Two patients in the autograft group continued to have hip donor site pain at 3 months. CONCLUSIONS: This study suggests that union rates of allograft and autograft (iliac crest bone graft) are equal. The use of allograft in the lateral column lengthening component of operative correction of adult stage II PTTI appears to be a viable alternative to the use of iliac crest autograft and eliminates the morbidity and increased cost associated with autograft harvest.     

Identification of the HLA-Cw*0774 and DQB1*060105 alleles

Cw*0774 differs from Cw*070201 by one nucleotide within the coding sequence of exons 2–4. DQB1*060105 differs from DQB1*060101 by one nucleotide within the coding sequence of exons 2–3.     

A novel HLA-C locus allele with codon 54 deletion, Cw*0346

This report describes the discovery and characterization of the novel Cw*0346 allele.     

Mechanical testing of fixation techniques for scaffold-based tissue-engineered grafts

Full-thickness defects in articular cartilage can be functionally restored by autologous chondrocyte implantation (ACI). In past years, numerous types of scaffolds for tissue-engineered cartilage implants have been developed and thoroughly characterized. However, the fixation stability of the implants has been rarely investigated despite its well-known importance for successful therapy. In this study, we have mechanically tested the fixation stability of four commonly used biomaterials for ACI attached by four different fixation techniques (unfixed, fibrin glue, chondral suture, and transosseous suture) in situ. Scaffolds based on polyglycolic acid (PGA) and polyglycolic acid and poly-L-lactic acid (PGLA), collagen membranes, and a gel-like matrix material were fixed within rectangular full-thickness cartilage defects of 10 x 15 mm(2) and loaded in tension until failure. Fibrin glue fixation of PGLA-scaffolds withstood a load of 2.18 6 +/- 0.47 N, chondral sutured PGA-scaffolds of 26.29 6 +/- 1.55 N, and transosseous fixed PGA-scaffolds of 38.18 6 +/- 9.53 N. The PGA-scaffold could be loaded highest until failure for all fixation techniques compared to the PGLA-scaffold and collagen membrane. Our findings serve as basis for selecting the most suitable fixation technique for scaffold-based tissue-engineered grafts according to the expected in vivo loads.