Cementless total knee replacement (TKR) is at the present date a controversial topic. Aim of the study was to compare the effect on tibial periprosthetic bone mineral density (BMD) between different implant materials and designs.

During the two-year period between January 2005 and December 2006, we analysed data of 45 patients who underwent consecutively cementless TKR (49 implants) at our Institution for primary osteoarthritis. Data was divided in 2 groups: A) 26 implants with tantalium tibial component (Zimmer NexGen Trabecular Metal^TM Monoblock); B) 23 implants with porous titanium tibial component (Lima MultiGen^TM). Data was comparable per sex, age, BMI, post-op alignment, post-op KSS > 75, absence of major post-op complications. Standard AP x-rays were taken 4 months post-op and 8 years post-op. In order to quantify the reduction of BDM, we determined using ImageJ (an open source software) the Mean Grey Value (MGV) of a specific area on the 4 months- and 8 yrs-postop AP x-rays.

Group A and Group B had an average MGV variation of, respectively, 11.79% and 10.51%; there was no statistically significant difference between the two groups.

Reduction of BMD in a TKR is known to be a biomechanical response to load and it is conditioned by the alignment of the components and their design. Our study shows that the different materials (porous titanium vs. tantalium), in relation to the different implant design, have a similar effect on the surrounding bone. The overall results show a valid osseointegration in both group of patients.

Aim of the study was to analyse the modifications of the pre-op and post-op femoral off-set after cementless total hip replacement.

During an 18-month period, from January 2015 to June 2016, we retrospectively analysed data of 79 (n = 81 hips) patients (M:F = 31:48), with an average age of 70.38 yrs ± 10.05, who consecutively affered to our Department and underwent cementless total hip replacement for primary osteoarthritis with Pinnacle Gription^TM cup and Corail^TM stem (Depuy). All cases of infections and revision surgery were excluded. Inclusion criteria: postero-lateral approach, 2 dedicated surgeons. All patients were clinically and radiographically evaluated at 4-months and 1-year postop. Preop and postop femoral off-set were calculated using Impax Agfa software.

Average preop HHS was 46.7 ± 7.7; at 4-months post-op 86.4 ± 5.7; at 1-year post-op 90.0 ± 5 (the improvement had a statistically significant p-value). There was no statistical significant difference between the preop and postop off-set values obtained (t-student test). In 38 (46.9%) hips we increased the femoral off-set and we analysed using χ₂-test if there was a correlation with hip pain, HHS and dislocation. There was no statistical significance.

Our overall results show good and excellent clinical results at 1 year follow-up in cementless total hip replacement. We believe that our pre-op digital planning of the implant and the offset obtained is a crucial step in determining these results.

Dysplasia epiphysealis hemimelica is a rare congenital abnormality of enchondral ossification of one or more epiphyses, thus determining an asymmetrical growth in that bone district. We are here considering 2 cases. The first case regards a 4-month-old female baby with an irreducible flexion of the right knee. The X-rays highlighted an area of different density with irregular contours and multiple ossifications; the MRI showed a bone lesion with osteocartilaginous structure in contiguity with the medial condyle; during the operation a osteocartilaginous formation partially fused with the medial condyle was observed. The second case regards a 10-month-old male baby, with a medial malleolus swelling. The X-ray highlighted an area of different density with irregular contours and multiple ossifications, medial to the epiphyseal nucleus of the talus; the MRI showed an osteocartilaginous lesion in contiguity with the talus; during the operation an osteo-cartilaginous formation fused with the talus was observed. The histological findings confirmed in both cases the presence of cartilaginous and bone tissue in absence of pathological lesions.

Being a lesion of malformative origin, the early removal of the abnormal ossification nuclei will permit to avoid the secondary lesions described in literature, like asymmetrical growth of the limb and functional limitation.