Pin loosening and infection are inherent complications of external fixation. This study deals with their effects of using either hydroxyapatite (HA)-coated or uncoated external fixation pins in leg-lengthening procedures on patients of short stature.

We used HA-coated pins on one side and uncoated pins on the other (randomly determined) in 28 bilateral lengthenings undertaken in 23 patients. A total of 322 pins was used. The mean implantation time was 530 days and the mean lengthening achieved was 78% of initial bone length. Mean extraction torque was 7611.6 Nmm degree⁻¹ for HA-coated and 85.4 Nmm degree⁻¹ for uncoated pins (p < 0.001). The rate of pin loosening was 4% (7/ 161) for HA-coated and 80% (129/161) for uncoated pins (p < 0.001). There was no statistically significant difference in the incidence of pin-track infection between the two groups.

The use of HA coating appears to be an effective method of reducing the incidence of pin loosening in external fixation with a long implantation time and for mechanically highly stressed procedures such as leg lengthening for short stature.

Introduction and Objectives: In this retrospective study, we have evaluated the results of treatment of non-unions of the humeral diaphysis using plate osteosynthesis.

Materials and Methods: This is a retrospective study covering the years 1997–2002, with a total of 135 fractures of the humeral shaft: 84% were treated orthopaedically and 16% surgically by means of plate osteosynthesis. We present 14 cases of humeral non-union, all of which occurred after orthopaedic treatment, and 12 of which were surgically treated by means of plate osteosynthesis (the other 2 declined surgical treatment). The most common cause of fracture was accidental fall, and of the 12 cases, 11 were female, and 1 was male. Mean age was 67.6 years. Initial orthopaedic treatments included the following: in 9 cases U-splint + sling, in 1 case U-splint + Velpeau sling, in 2 cases hanging cast + Poulipen. Of these, the initial bandaging was replaced with braces after 2.5-3 months. Definitive surgical treatment was delayed an average of 8.1 months. We used the Müller-AO fracture classification system. There were 4 cases with 12B12, 3 cases with 12A12, 1 case with 12A11, 1 case with 12B22, 1 case with 12B11, 1 case with 12B21, and 1 case with 12A21. Surgical treatment was performed in 7 cases with LD-DCP plates, in 3 cases with DCP plates, in 1 case with a T-plate, and in 1 case with a straight plate. Corticocancellous bone grafts were transferred from the iliac crest in 9 of 12 cases.

Results: Bone healing was achieved in 11 of 12 surgical cases (one case without radiographic consolidation due to detachment of the plate due to trauma). In 2 cases there was a limitation of shoulder abduction at 85° and elbow extension -10°. In one case, there was repeat treatment due to failure of osteosynthesis. In two of the surgical cases, definitive BA will be measured upon completion of rehabilitation. Complications included 2 temporary radial palsies that recovered both motor and sensory function, one distal detachment of the plate due to previous trauma that had borderline BA and was non-painful. There was one case in which consolidation did not occur and where the humeral artery was injured iatrogenically during surgery (the same one that required repeat surgical intervention). There was one case of infection of the site of osteosynthesis due to Pseudomonas aeruginosa, which responded well to initial antibiotic treatment, and no material needed to be removed.

Discussion and Conclusions: Plate osteosynthesis is an effective treatment for non-unions of the humeral shaft and yields good joint mobility and few complications (similar to the results of other treatment methods) and must be performed by experienced surgeons.

Introduction and Objectives: Severe proximal femoral defects are a major problem in femoral stem revision surgery. Various surgical techniques have been described that aim to resolve the deficit of bone stock: the Exeter technique or impacted allograft bone, long porous surface distal fitting stems, stems coated with hydroxyapa-tite, and modular stems with metaphyseal fixation. In 1987, Wagner presented a revision technique using a long distal fitting conical stem with excellent proximal bone regeneration. However, the Wagner stem presents two fundamental problems: subsidence and dislocation. Furthermore, it is a demanding technique that requires preoperative planning. Conical fixation makes adjustment of length and anteversion more difficult, as it is dif-ficult to change these parameters after impaction.

Materials and Methods: This is a retrospective study of the first 86 Wagner prostheses implanted at our centre.

Results: The reason for revision was aseptic loosening in 81.8% of cases. A morselised bone graft was used in the femur in 22% of cases. Average follow-up period was 6.5 years. Complications occurred in 33% of cases. Half of these complications were perioperative fractures of the femur, which for the most part required no additional treatment besides intervention during the operation. Of the 6.8% of implants that were loose, only 3 cases required surgical treatment. Subsidence occurred in 40.9% of implants, with a median of 13.5mm. Of the 40.9% of implants that sank, two-thirds sank more than 0.5cm. Average metal-bone contact was 27.57mm postoperatively, 39.9mm at one year postoperatively, and 50.38mm at final evaluation.

Discussion and Conclusions: The Wagner prosthesis has yielded good results in revisions with proximal bone defects. However, it presents a high rate of dislocation and subsidence, in relation to the technical demands of the procedure.

Background: Tibial valgus, a known complication of leg lengthening by external fixation, has been related to stability of the bonefixator system and, in particular to pin loosening. Hydroxyapatite coating has been reported to enhance the quality of the bone-pin interface. The aim of this study was to compare the incidence of axial deformity between tibial lengthening procedures with hydroxyapatite-coated and non-coated external-fixation pins.

Methods: A prospective trial was conducted on 34 symmetrical tibial lengthenings in 17 pathologically-short patients. For each pair of bones, one side to be lengthened with hydroxyapatite-coated pins and the other with standard uncoated pins were randomly selected. The bone angle in the frontal plane was measured before the operation and at the end of the fixation period. The difference was calculated and compared between lengthenings performed with coated and uncoated pins.

Results: Mean deviation into valgus of the tibiae was 6.5° with hydroxyapatite-coated pins and 12.5° with uncoated pins (p=0.023). Other factors previously related to valgus deformity did not significantly differ between groups.

Conclusions: Tibial lengthenings performed with hydroxyapatite-coated external-fixation pins are less prone to axial deviation in the frontal plane than those without it.