Introduction

The management of adolescent hallux valgus (AHV) remains controversial, with reservations about both conservative and surgical treatments. Non-operative management has a limited role in preventing progression. Surgical correction of AHV has, amongst other concerns, been associated with a high prevalence of recurrence of deformity after surgery. We conducted a systematic review to assess clinical and radiological outcomes following surgery for AHV.

Aim: To compare acetabular development and hip stability over time in patients treated for developmental dysplasia of the hip (DDH) by open reduction combined with either varusderotation (VDRO) or innominate (IO) osteotomies.

Method: Patients who underwent open reduction for DDH, combined with either VDRO (38 patients) or IO (33 patients), between 15 months and 4 years of age were reviewed. Both groups comprised a single surgeon consecutive series, differing only in the type of osteotomy performed. A total of 490 postoperative radiographs over a maximum follow-up period of 13.6 years were analyzed. We used repeated measures analysis of variance to compare the change in acetabular index (AI) as well as several other radiographic indices of acetabular development and hip stability over time.

Results: After osteotomy, the AI decreased in both groups but the magnitude of the decrease was significantly different between groups over time (p< 0.0001). The AI of patients undergoing VDRO never decreased as much as that of patients undergoing IO, with a mean difference of 10.4 degrees after 4 years (p< 0.0001). Similarly the IO group demonstrated more favourable acetabular architecture and hip stability over time compared to the VDRO group, as quantified by change in the acetabular floor thickness (p< 0.03), lateral centring ratio (p< 0.0001) and superior centring ratio (p < 0.0001).

Conclusions: Acetabular remodelling after IO was more effective at reversing acetabular dysplasia and maintaining hip stability than VDRO. Long-term follow-up of VDRO will be necessary to determine if late improvement occurs. IO may be preferable over VDRO in the treatment of hip dislocation after walking age.

Carbonate-substituted hydroxyapatite (CHA) is more osteoconductive and more resorbable than hydroxyapatite (HA), but the underlying mode of its action is unclear. We hypothesised that increased resorption of the ceramic by osteoclasts might subsequently upregulate osteoblasts by a coupling mechanism, and sought to test this in a large animal model.

Defects were created in both the lateral femoral condyles of 12 adult sheep. Six were implanted with CHA granules bilaterally, and six with HA. Six of the animals in each group received the bisphosphonate zoledronate (0.05 mg/kg), which inhibits the function of osteoclasts, intra-operatively.

After six weeks bony ingrowth was greater in the CHA implants than in HA, but not in the animals given zoledronate. Functional osteoclasts are necessary for the enhanced osteoconduction seen in CHA compared with HA.

Introduction; In contrast to hydroxyapatite (HA), carbonate substituted hydroxyapatite (CHA) is resorbed by osteoclasts, and is more osteoconductive in vivo. On bone, osteoclastic resorption results not only in topographical changes, but also changes in the proteinaceous matrix within the resorption pit to which osteoblasts respond [1]. This study sought to investigate a possible link between the different bioresorptive properties of these biomaterials and subsequent bone formation on their surfaces, analogous to the coupling seen in normal bone remodelling.

Methods; Phase-pure HA and 2.7wt% CHA were prepared by aqueous precipitation methods [2] and processed into dense sintered discs for cell culture. Human osteoclasts derived from CD14+ precursors were cultured for 21 days on discs of HA and CHA; subsequently, cells and the proteinaceous layer were removed from some discs leaving a topographically altered surface (assessed by SEM and profilometry), whilst in others the proteinaceous layer was left intact. Control (unresorbed) discs were also prepared. The discs were then seeded with human osteoblasts (HOBs) which were cultured for up to 28 days, in some cases in the presence of hydrocortisone and â-glycerophosphate. Proliferation (MTS assay), collagen synthesis (3-H Proline incorporation), and the formation of mineralised nodules (tetra-cycline labelling [3] and SEM) were assessed.

Results; Osteoclasts altered the ceramic surfaces. Large pits were seen on CHA in contrast to limited erosion of the HA surface, accompanied by a greater increase surface roughness (Ra) (p< 0.05). After 6 days of culture, proliferation of HOBs was increased on resorbed discs provided the proteinaceous layer resulting from osteoclastic activity was left intact. At 28 days, cells had formed confluent sheets and there were no significant differences in their number. At 6 days, collagen synthesis by HOBs on CHA was increased on resorbed surfaces, and further increased if the proteinaceous layer was left intact. A similar response was seen on HA, but not until 28 days. Mineralised nodules formed after 28 days of culture in the presence of hydrocortisone and â-glycerophosphate on tissue culture plastic, but not in their absence. By contrast on the ceramics there was no evidence of mineralised nodule formation on any of the discs, although globular accretions were present in small amounts throughout the collagenous matrix regardless of the presence or absence of supplements.

Conclusion; Prior osteoclastic activity on HA and CHA affects subsequent proliferation and collagen production by HOBs. The effects of topographical alteration and matrix conditioning appear synergistic, and are apparent at an earlier time-point on a more resorbable ceramic. Osteoclastic activity may be important in the osteoconductive properties of biomaterials.

Retrospective study of management and outcome of periprosthetic femoral fractures, in a lower limb reconstruction, reference centre.

144 fractures over a period of 20 years were reviewed. The Vancouver system was used to classify the fractures. The prosthesis length was measured pre and post operatively. The use of impaction grafting technique to compensate for inadequate bone quality of the surrounding bone was assessed (type B3 fractures). The use of Dall/ Miles, DCP and Mennen plates also assessed. Healing was defined using radiological and clinical criteria. Chi-square test with p< 0.05 was used for the analysis of the results.

When the Vancouver system was applied 2.85% of the fractures were classified as type A, 87.2% as type B and 10% as type C. Within type B group 13.2% were subtype B1, 12% subtype B2 and 62% subtype B3. Better healing achieved when the revision stem was bypassing the most distal fracture line (p=0.005). Better healing achieved when impaction grafting was used for B3 fractures (p=0,0001). 1 out of 6 Mennen, 4 out of 16 Dall/Miles and 2 out of 20 DCP plates used failed. Overall 68% healing, 5% non-union, 1% infection, 24% re-fracture rate at 12 months follow up.

Impaction grafting could compensate for the inadequate bone in type B3 fractures. Revision stem should bypass the most distal fracture line to achieve healing. DCP plates do better than Dall/Miles. Mennen plates have got special indications.