Enhancing proximal femoral pressure during cemented stem insertion.

BACKGROUND: Poor proximal femoral pressures during a cemented primary hip replacement may compromise proximal fixation and cause early aseptic loosening. Occlusion of the calcar, during stem insertion, achieves a uniform and sustained rise in the proximal intra-medullary pressure, which should enhance cement penetration into bone and improve long-term survival of the prosthesis. METHODS: 54 Exeter stems were cemented into femoral moulds prepared from plaster of Paris. Pressure transducers were connected to the proximal, middle and distal zones of the mould. After cement insertion, stems were implanted with occlusion of the calcar by either nothing, a thumb placed medially or an Exeter horse-collar. 18 stems each were inserted into Palacos-R at 3½-4 minutes and 4-4½ minutes after mixing and Simplex-P 6-6½ minutes after mixing and the intra-medullary pressures were measured. Data were subjected to regression analysis using SPSS. RESULTS: Proximal and distal intra-medullary pressures were significantly higher (P < 0.01-0.001) with proximal occlusion in all cements. The highest pressures were achieved with Palacos-R at 4-4½ minutes after mixing, with proximal thumb occlusion. Stem insertion into Palacos-R at 3½-4 min. or 4-4½ min. after mixing, gave higher pressures than into Simplex-P regardless of the method of occlusion. With Simplex-P, there was a trend to higher proximal intra-medullary pressures with the horse-collar. CONCLUSION: Occluding the calcar during stem insertion into cement achieves and sustains high intra-medullary pressures in both the proximal and distal femur. The highest pressures are obtained with stem insertion into Palacos-R at 4-4½ minutes after mixing, with proximal thumb occlusion. A horse-collar achieves slightly higher pressures with Simplex-P.

Tibiotalocalcaneal arthrodesis with a curved, interlocking, intramedullary nail.

BACKGROUND: Tibiotalocalcaneal fusion with a straight rod has a risk of damaging the lateral plantar neurovascular structures and may interfere with maintaining normal heel valgus position.We report the results of a prospective study of tibiotalocalcaneal (TTC) arthrodesis with a short, anatomically curved interlocking, intramedullary nail. MATERIAL AND METHODS: Forty-five arthrodesis in 42 patients, performed between Jan 2003 and Oct 2008, were prospectively followed. The mean followup was 48 (range, 10 to 74) months. The main indications for the procedure were failed ankle arthrodesis with progressive subtalar arthritis, failed ankle arthroplasty and complex hindfoot deformity. The outcome was measured by a combination of pre and postoperative clinical examination, AOFAS hindfoot scores, SF-12 scores and radiological assessment. RESULTS: Union rate was 89% (40/45). Eighty-two percent (37/45) reported improvement in pain and 73% (33/45) had improved foot function. Satisfactory hindfoot alignment was achieved in 84% (38/45). Postoperatively there was a mean improvement in the AOFAS score of 37. Complications included a below knee amputation for persistent deep infection, five nonunions, and three delayed unions. Four nails, six proximal and six distal locking screws were removed for various causes. Other complications included two perioperative fractures, four superficial wound infections and one case of lateral plantar nerve irritation. CONCLUSION: With a short, anatomically curved intramedullary nail, we had a high rate of tibiotalocalcaneal fusion with minimal plantar neurovascular complications. We believe a short, curved intramedullary nail, with its more lateral entry point, helped maintain hindfoot alignment.

Primary total knee replacement: is suction a portal of infection?

INTRODUCTION: Pulsed lavage during a total knee replacement usually leaves a pool of fluid on the surgical drapes. It is common practice to suck away this fluid using the same suction device used intra-operatively. This could be a cause of direct wound contamination. We hypothesised that bacteria contaminate fluid that collects around the foot in total knee replacement surgery and that suction equipment could be a portal of contamination. We also hypothesised that bacterial count in the fluid is lower if chlorhexidine, rather than saline, is used in the pulsed lavage. PATIENTS AND METHODS: Forty patients undergoing primary total knee replacement were divided into two groups. The first group had pulsed lavage with normal saline and the second with 0.05% chlorhexidine. RESULTS: At the end of the operation, 20 ml of fluid, pooled on the surgical drapes was aspirated and cultured for bacterial growth. None of the fluid samples showed bacterial growth. CONCLUSIONS: Suction device used peri-operatively during knee replacement is unlikely to be a cause of wound contamination. Pulsed lavage with normal saline is as effective as lavage with chlorhexidine.