Introduction: Computer assisted-surgery (CAS) brings in a great precision to the alignment of the components and the axis of the extremity in total knee arthroplasty (TKA). On the other hand, even though the MIS technique exerts a lesser aesthetic impact, favours the faster recovery of the patient and preserves the soft parts better, it can also lead to mistakes in the alignment of the implant due to the deficient visualization. Adding CAS to MIS may solve this potential complication.

Objective: To compare the alignment of the components with regard to the mechanical axis in four TKA groups (standard surgery, MIS surgery, standard surgery with CAS, and MIS with CAS).

Materials and Methods: Prospective and randomized study. 100 patients with Alhbäck degree III primary degenerative osteoarthritis of the knee and less than 10° of varus-valgus were included. The patients were randomly distributed in 4 groups of 25 patients each, and the same surgeons performed the surgery. Two CT surviews were performed on every patient, one preoperatively and one during the immediate postoperative period, including hip and ankle, where the femoral, tibial and femoro-tibial axis measurements were carried out.

Results: Mean age was 71.63 years (SD 6.68); 81 % of patients were women. Preoperative mean varus was of 7.57° (SD 1.10). No significant differences were found in the femoro-tibial alignment nor in the components with regard to the mechanical femoral axis between the four groups (Table 1). Nevertheless, significant differences in favour of the MIS-CAS technique group for the alignment of the tibial component with regard to the mechanical tibial axis were found.

Conclusions: The MIS technique allows for a well-aligned TKA implantation. Nevertheless, when CAS is coupled with this technique, the alignment of the tibial component is improved. It is possible for the association of MIS and CAS to become a true advance in TKA implantation.

Aim: To compare the in-vitro elution characteristics of CMW1 and Palacos R bone cements containing gentamicin or teicoplanin or a combination of both.

Materials & Methods: Four types of bone cement discs (28x22mm) were prepared.

Disc 1(control) contained Palacos R or CMW1 cement without any added antibiotic.

The discs containing teicoplanin were prepared by adding teicoplanin powder (2gm) to the respective cement powder (40 gm with or without 0.5gm of gentamicin) and then adding the monomer (vacuum mixing).

All the discs were immersed in 50 ml normal saline bath in a sterile pot and maintained at temperature of 37 deg Celsius. 24 hours later a 5ml sample was taken from each pot for assay, to measure the amount of antibiotic eluted, using fluorescence polarization immuno-assay technique. The discs were then removed from the pots, washed with normal saline and reimmersed in a fresh 50 ml saline pot. This procedure was repeated at hours 48, 72, 120 and week 1, 2, 3 & 6 for all discs.

Results: All discs and assays were done in triplicate and average total value at 6 weeks (μ gm/ml) taken for statistical analysis.

CMW1:

Gentamicin eluted from disc4 was higher than disc2 (94.9 v 34.37. p< 0.0003).

PALACOS R:

Gentamicin eluted from disc4 was higher than disc2 (144.17 v 86.43. p< 0.0004).

Conclusion: Palacos R cement elutes more antibiotic than CMW1 and antibiotic combination in bone cement resulted in, mostly, synergistic effect of increased elution of individual antibiotic.

Background: Measurement of quality of life (QOL) and functional status provides important additional information for priority setting in health policy formulation and resource allocation. Our aim was to define the differences in the health-related quality of life between hip artroplasties with cementation and without cementation. The last objective was to reunite evidences on the advantages and disadvantages of both systems of hip arthroplasty fixation. Methods: We analyzed a random sample of patients in surgical waiting list of total hip arthroplasty, between 65 and 75 years, divided in two groups of 40 patients who received a cemented or uncemented THA, respectively. We compared the pre-operative characteristics and at a year after operation changes in the Nottingham Health Profile (NHP) and SF-12 self-administered questionnaires. We also performed the specific Harris hip score. To make the different scoring systems comparable, all scores were transformed to a 0-to 100-point scale, with 100 points indicating best health. Differences among these groups were compared using the Mann-Whitney U test. Results: All patients increased their QOL scores. Both groups had similar QOL scores before surgery. At 1 year, patients with the uncemented prosthesis had slightly higher scores for energy, pain, and emotional reaction. Changes in QOL scores were, however, very similar. Conclusions: The use of an uncemented prosthesis does not impair early outcome.

Background: Total knee replacement (TKR) failure is usually due to alignment, stability or fixation defects. Objective: To quantify the loads distribution using an absorptiometric method with two different tibial stems.

Methods: We analyzed 20 patients with cemented TKR, in two groups: one of them cylindrical and the other with cruciform stem. We studied the periprosthetic bony density evolution in three areas: under the stem, internal and external baseplate. We performed dual-energy x-ray absorptiometric (DEXA) measurements at 2, 3 and 7 years of follow-up.

Results: The evolution of the bony density under the internal baseplate to 2 and 3 years decreased from 0.920.20 to 0.900.19 g/cm2; under the external baseplate changed from 0.970.36 to 0.970.38 and under the stem raised from 1.050.25 to 1.080.26 in the cylindrical group. In the cruciform group, under the internal baseplate decreased from 0.750.08 to 0.710.05, under the external one decreased from 0.890.01 to 0.850.07 and under the stem changed from 1.060.06 to 1.040.29.

Comparing only the cylindrical subgroup (three missing patients), the DEXA measurements at 2, 3 and 7 years of follow-up were: 0.88, 0.84 and 0.80 g/cm2 under the internal baseplate; 0.79, 0.78 and 0.77 under the external one, and 0.99, 0.96 and 0.99 under the stem.

Conclusions: Loss of bony density is observed progressively after TKR. Comparativily, the diminution is greater for the cruciform stem. The internal compartment is more affected.

Introduction/objective: The results of Charnley total hip replacement, when performed in the general setting, may not be as good as expected (1). The objective is to know the long time survival in a Charnley low friction arthroplasty series performed in a General Hospital.

Material and methods: To have a minimum follow-up of ten years, we analysed 404 cases from a 431 series implanted in our department between 1976 and 1993. Mean age was 67 years, 57% were women.

The survival was calculated used Kaplan-Meier method, considering revision surgery as the analyzed event. Age and gender relation with survival were analyzed using the Log-Rank test.

Results: The survival of the Charnley low friction arthroplasty with the 95 % confidence interval was 92% (95–89%), 87% (90–81%), and 83% (89–78%) at 10, 15, and 20 years respectively. Patients younger than 60 years in the surgery time had lower survival than the older group for the acetabular (Log-Rank test p=0.043) and femoral components (Log-Rank test p=0,0085). There is not a statistically significant difference related to gender.

Conclusions: The survival in our low friction arthroplasties series at 10, 15, and 20 years is similar to the found in multicentric studies performed in other centres with special dedication to the surgery of the hip (2). Age affected the likelihood of long-term survivorship of the acetabular and femoral components used in Charnley low friction Arthroplasty.

Aims: To study the utility of a computer assisted orthopaedic surgery (CAOS) wireless system (navigator) in Total Knee Arthroplasty (TKA). Methods: Randomised prospective study. A sample of 40 TKA patients was randomised in two groups: CAOS was used in 20 of them. In the other group standard technique with manual alignment was performed. Femoral angle (formed between the femoral mechanical axis and the femoral component), tibial angle (formed between the tibial mechanical axis and the tibial platform) and femorotibial angle (formed between femoral and tibial mechanical axes) were measured from Computed Tomography Surviews taken in the immediate postoperative period. Results: In the standard group (without navigator) the femoral angle mean was 91.7° (ranged 90 to 94°). Tibial angle mean was 90.2° (87°–95°) and femorotibial angle mean was 175.9° (172°–180°) showing a slight prevalence of varus deviation of the extremity mechanical axis. In the group with navigator the femoral angle mean was 90.2∞ (87–93°), tibial angle mean 89.6°(85°–93°) and femorotibial angle mean 179.2° (177°–182°). There were statistically significant differences between groups for the femoral angle (p=0.001), and the femorotibial angle (p < 0.001). An ideal femorotibial angle (180±3°) was achieved for all the patients of the CAOS group but only 9 patients of the standard technique group reached this objective (p< 0.001). Conclusions: The use of CAOS for TKA favors the implant placement in a position nearer to the ideal mechanical axis.

Purpose: Transfer of the vascularised fibula causes an imbalance in the lower limb due to the small calibre of the bone compared with the recipient bone (femur, tibia). “Femorisation” or “tibialisation” is slow, requiring prolonged protection with an orthesis. The doubled fibula or “shotgun” technique which maintains fibular periosteal vascularisation may overcome this inconvenience.

Material and methods: We report a series of eight free vascular shotgun fibular transfers at a mean four years follow-up (1–11). The recipient site was the lower limb in all patients who had undergone multiple operations, seven for chronic osteitis and one for chondrosarcome (five femoral supracondylar grafts, one knee arthrodesis, two metaphyseal tibial grafts). A cortico-cancellous autologous graft was associated during the same operation for six patients; Osteo-synthesis was achieved in seven cases with an external fixator and in one case with locked centromedullary nailing.

Results: The bone scintigraphy obtained in all cases at the third postoperative day showed intense uptake in the graft in six cases. We had seven cases of osteitis with no case of recurrent sepsis. Mean delay to bone healing assessed radiographically was 5.2 months. Hypertrophy of the fibula was noted at last follow-up in four cases. The external fixator was removed on the average at 6.8 months (5–9). Weight bearing was allowed in all cases with an adjustable protective orthesis. There was one fracture of the graft in a patient with a knee arthordesis which was treated with a corticocancellous autologous bone graft.

Conclusion: This series demonstrates the interest of doubling the free fibular transplant compared with other bone transfers to the lower limbs, improving the balance of the bone calibre and resistance. For patients with loss of supracondylar femoral bone, we describe a widened posterior access allowing the preparation of the recipient site with a single installation for the graft harvesting and fibular transfer.