The biological acetabular reconstruction with bone allografts in hip revision arthroplasty

BACKGROUND

Reconstructions in case of acetabular bone loss in hip revision arthroplasty are challenging. A few techniques have been proposed, with inconstant outcomes. Biological reconstructions using bone allografts may address the acetabular bone loss and restore the hip anatomy. Aim of this work was the description of the surgical technique and the evaluation of the outcomes using a regional arthroplasty register.

MATERIALS AND METHODS

Minor or massive bone allografting was performed in hip revision arthroplasties in a tertiary center. Bulk allografts were used in severe acetabular bone losses. Fresh-frozen femoral heads were impacted in the bone cavity and porous cups were implanted; multihole sockets were used when necessary. In DeLee A zone, no grafts were used in order to reduce overstress graft resorption. The results were evaluated using a regional arthroplasty register, and a comparison with revisions without bone grafts was performed investigating re-revision rates and reasons for further revisions.

RESULTS

At 10 years, acetabular revisions with bone allografts achieved a similar survival rate than revisions without bone grafts. The re-revisions occurred more frequently in revisions without bone allografts (10.8 vs. 9.7%). In the allograft cohort, septic loosening was lower (0.3 vs. 2.6%), whereas a higher rate of aseptic cup loosening was experienced (2.7 vs. 1.4%).

CONCLUSIONS

Bone allografts may provide a good restoration of the acetabular bone stock and the hip biomechanics. Septic loosening does not seems a major concern, whereas a higher rate of aseptic cup loosening should be expected when bone grafts are used.

Preventive cobalt therapy in heterotopic ossification consequent to prosthetic hip reimplantation

Prosthetic hip reimplantation is considered to be a procedure at risk for the development of periprosthetic heterotopic ossification, which may be responsible for functional limitations of the hip operated on. Preventive treatment may be carried out with radiation or drug therapy. The authors report the results of 54 cases submitted to prosthetic reimplantation and treated by cobalt therapy, as compared to the results of 76 reimplantations (control group) that did not undergo any kind of treatment: the occurrence of high grade ossification (exceeding Brooker grade III) was 2% in cases treated, as compared to 9% in those not treated. Males were more at risk for the development of ossification.

Hip arthroplasty in the elderly patient: is it a correct indication?

The authors report the results of 54 primary hip arthroplasty implants performed in patients aged over 75 years. The cases examined demonstrated that this type of surgery is not contraindicated in elderly patients as the occurrence of complications and perioperative risks are not higher if compared with a "younger" population. Preoperative anesthesiological evaluation that is extremely accurate is required.

Antibiotic and antithromboembolic prophylaxis in hip arthroplasty (a review of 700 primary implants)

The authors report the results obtained with antibiotic and antithromboembolic prophylaxis used in 700 consecutive primary total hip arthroplasties. As for antibiotic prophylaxis (5 cases of infection: 0.7%) the various types of antibiotic used always kept the infection rate under 1%, confirming the effectiveness of the preventive use of antibioticotherapy. The incidence of deep venous thrombosis and pulmonary embolia were 3.7% and 0.7%, respectively (26 cases of DVT and 5 of PET). The incidence of DVT rose to 34.4% in a selected group of cases in which phlebography had been carried out even in the absence of symptoms of DVT. This confirms that the routine use of this method would without a doubt be useful in preventing complications with a high risk for the life of the patient (pulmonary embolia). As for pharmacological prophylaxis, indobufene and calcium heparin were the drugs used most: their effectiveness was nearly similar, despite the fact that the use of calcium heparin in patients considered to be at a higher risk for thromboembolic complications should be made clear.

Removal of heterotopic ossifications followed by cobalt therapy after hip arthroplasty

The authors report 7 cases in which removal of high grade ossification which developed after hip arthroplasty was performed: all of the patients were treated postoperatively by radiation therapy with the purpose of preventing recurrence of ossification. After surgery ossification was present, but to a moderate degree, in 6 out of 7 cases examined; movement had clearly improved. The results obtained show that removal surgery is justified if movement of the hip is considerably impaired (ankylosis) and that prevention plays an essential role and must be carried out every time that the patient risks the development of ossification.

Two cases of hyperparathyroidism initially diagnosed as aneurysmal cyst

The authors present two cases of primary hyper-parathyroidism initially diagnosed as aneurysmal cyst. The aspects of differential diagnosis are discussed, and the importance of evaluating all of the diagnostic elements in order to formulate a correct diagnosis is emphasized.

Hydroxyapatite as metallic prosthesis coating: preliminary clinical experience

The authors report the radiographic results of 65 An. C.A. prosthetic stems coated with hydroxyapatite and followed-up at least 24 months after implantation. A comparison with a homogeneous group of aluminum-coated An.C.A. stems showed that hydroxyapatite-coated stems are characterized by better osteointegration, with a clearly inferior incidence of radiolucent lines at the bone/prosthesis interface. Macroscopic observation and histologic examination carried out on two stems removed because of persistent pain to the thigh revealed partial resorption and fragmentation of the coating. The authors believe that this phenomenon, the object of other observations reported in the literature, may indicate the reduced stability of the coating in the long run, and as such further in-depth study is required.

Wear in carbon fiber-reinforced polyethylene (poly-two) knee prostheses

The authors report a case of massive wear of carbon fiber-reinforced polyethylene used as an insert in a knee prosthesis. The finding, which was studied under a scanning electron microscope, in agreement with mechanical resistance and laboratory testing reported in the literature, confirms that this composite material (poly-two) is not more advantageous to use that ultra-high molecular weight polyethylene in terms of wear, despite favorable experimental premises.

The use of cobalt therapy to prevent heterotopic ossification after total hip arthroplasty

The occurrence of heterotopic ossification after total hip arthroplasty may be prevented by radiation or medical therapy. The authors report the results obtained in 96 cases treated by cobalt therapy: the occurrence of high grade ossification (Brooker III and IV) is equal to 1% in cases treated, as compared to 9% in cases not treated. Male patients of advanced age and who are characterized by primary arthrosis are more at risk for ossification.

Indications and limits of CT scan in prosthetic loosening

The authors attempt to define the role of computed tomography (CT) in the study of loosened hip prosthesis. To this purpose they have studied 30 patients with clinical and/or radiographic findings of loosening, carrying out a conventional radiographic assessment and a CT scan of the hip in question, and then comparing them. They conclude that CT scan when carried out according to the correct procedures described is very useful. Despite the presence of technical artefacts due to the presence of the metal prosthesis, the test makes a considerable contribution, not so much to the diagnosis of loosening in itself, which continues to be a clinical-radiologic diagnosis, rather to the evaluation of the morphostructural states of the acetabular bone for correct planning of surgery.

Diagnostic protocol in prosthetic loosening

The authors report the results they obtained in 35 cases studied based on a protocol to identify prosthetic loosening and to preoperatively establish its possible septic etiology. After clinical and radiographic assessment, the protocol called for a total body bone scan with Tc 99 m which, in positive cases, were associated laboratory tests and further instrumental testing (CT, bone scan and needle aspiration). Thanks above all to bone scan with labelled granulocytes the protocol provided high accuracy (91.4%) in preoperatively identifying the causes of infection.

Which length for the revision stem?

The results of 79 stem implantations performed between 1981 and 1992 are presented. Mean clinical and radiographic follow-up was obtained 36 months after surgery. All of the prostheses were substituted due to aseptic loosening: of these 68% were cemented. Femoral osteolytic lesions secondary to loosening was classified based on the Paprosky protocol. A severe femoral osteolytic defect (type 2b, 2c or 3 according to Paprosky) was associated with 4% of the cases of loosened cementless prostheses, and with 37% of the cemented ones. Homoplastic bone grafts were used in 40% of the patients. The length of the stems used for reimplantation was short (12-13 cm) in 43%, standard (17-18 cm) in 49%, and long (> or = 22 cm) in 7% of the cases. These stems were cemented in 32% of the cases. The incidence of cementation was different in relation to length, as 62.5% of the short stems were cemented, as compared to 5.3% of the stems of standard length. Clinical results were excellent in 90% of the cases submitted to surgery with short stems, in 80% of those treated with standard stems, and in 50% of the cases of revision surgery where long stems were used. Radiographically, 97% of the short stems were osteointegrated, as compared to 94% of the standard stems and to 25% of the long ones, which were only used in a very few cases to be considered quite complex ones.

Gout arthropathy: description of an atypical case

The authors describe a case of gout localized in the knee, the clinical and radiographic signs of which may lead to numerous diagnostic interpretations. Other affections with which differential diagnosis is difficult are reported, and principal diagnostic tests are described.

External humeral condylar fracture in children. A long-term review of 30 cases operated

Follow-up ranging from 2 to 14 years (mean 6 years) was obtained for 30 fractures of the external humeral condyle in children aged from 2 to 11 years; the patients had been submitted to reduction-osteosynthesis. Twelve patients were at the end of the growth period when followed-up. All of the patients were classified as Lagrange and Rigault grades II and III. Synthesis always involved two or three Kirschner wires bent under the skin. There were 24 perfect results and 6 good ones. Valgus equal to less than 10 degrees was present in 2 cases. Deficit in flexion-extension, present in 4 cases, did not exceed 20 degrees overall. Another case showed "fish-tail" radiographic deformity (due to epiphysiodesis) which did not interfere with function. Despite the potential danger of the lesion, the authors believe that careful surgical treatment provides very satisfactory results.

Neurogenic arthropathy. Differential diagnosis

Neurological affections responsible for secondary arthropathic pathology are: tabes, syringomyelia, diabetes mellitus, congenital insensitivity to pain syndrome, alcoholism, leprosy. Each of the affections shows predilection for specific joints: syringomyelia the shoulder, tabes the hip and knee, diabetes mellitus the foot, congenital insensitivity to pain the lower limb, alcoholism the shoulder and knee. The authors discuss two cases of hip arthropathy in previous dorsal myelic fractures.