Introduction

Bone loss management represents one of the most challenging issues for the orthopaedic surgeon. In most cases, stems, structural allograft, TMcones, and sleeves are adequate to allow optimal implant stability and durable fixation. In selected cases of wide metadiaphyseal bone defects, these devices do not provide proper intraoperative stability. In such scenarios, further steps are needed and include complex modular reconstruction, substitution with megaprosthesis (exposing patients at high risk of early failure) or joint arthrodesis that can yield unacceptable results. The aim of this paper is to present early results obtained with a new custom-made implant for complex metadiaphyseal bone defects management in knee revision surgery. By means of case presentations the authors would highlight the possibilities and technical notes of this novel device in complex knee revision surgery.

Aim

Femoral or tibial massive bone defects (AORI F2B-F3 / T2B-T3) are common in septic total knee replacement. Different surgical techniques are described in literature. In our study we show clinical and radiological results associated with the use of tantalum metaphyseal cones in the management of cavitary bone defects in two-stage complex knee revision.

Prosthetic joint infections (PJI) occur in 0.8–1.9 % of arthroplasties, but the absolute number is increasing because of the frequency of procedures. Two stage exchange is the most effective strategy, but failures are often described. Culture of perioperative tissues during removal of arthroplasty is a standard procedure but culture during second step is equally important to define a success or a failure.

We retrospectively reviewed PJI treated with two stage-exchange from January 2011 and December 2012 at “Ospedale S. Maria Misericordia”, Albenga-Italy. The procedure calls for bacterial culture not only during first step but also during reimplantation. Antibiotic treatment is prolonged after reimplantation until the cultures availability. A failure was defined by persistence of infection for positive culture or reocurrence of infection during a follow up of at least 2 years in patients with negative cultures. Three positive cultures yielding phenotypically identical organisms, or a single specimen of a virulent microorganism (e.g. Staphylococcus aureus) were required to rule out false positive for contaminants. Patients with persistence of infection were treated for 3 months with antibiotics.

86 patients underwent the two stage treatment: 45 hip and 41 knee prosthesis. The average ESR before arthroplasty removal was 59 mm/ 1st h (range 5–120), the average CRP was 3.9 mg/dl (range 0.3 – 34). Coagulase-negative staphylococci were isolated in 31 cases, Staphylococcus aureus in 19, Streptococcus spp in 8 and enterococci in 4. Gram-negatives were isolated in 4 patients and polymicrobial infection in 6 patients. In 14 patients (16%) no pathogen was identified.

A positive culture during reimplantation was documented in 11 (13%) cases: 8 coagulase-negative staphylococci, 2 Staphylococcus aureus, 1 Candida sp. All patients received 3 months of therapy after surgery and 6 of them were free of infection at 2 years of follow up after the end of treatment. Among the 75 patients with negative cultures, a relapse was documented in 2 (3%), after 5 and 24 months, respectively. These cases were treated with arthrodesis and 6 weeks antibiotic treatment, with resolution of infection but poor functional results. Overall the success rate of our strategy was 92% (79/86).

In patients treated with two-stage exchange, the combination of cultures at reimplantation and antibiotic suppressive treatment for 3 months in presence of positive cultures, are associated with a high rate of success. Only a prolonged follow up can rule out a relapse and agree with a true resolution of infection.

In bone infections, it is of fundamental importance to wrap any orthopaedic surgical procedure in healthy vascularised soft tissue, in order to allow good healing and to prevent infection recurrence.

Vitality of soft tissues around the knee joint can be easily jeopardized in patients undergoing multiple surgical operations as in case of infected arthroprostheses. In addition, there are very few local options in the soft tissue reconstruction of this area, due to the fact that the vascularisation of skin and subcutaneous tissue is based on the genicular arteries’ axes which prohibits the use of random skin flaps.

Preoperative planning of cutaneous incisions and reconstructive procedures is mandatory for a correct surgical treatment.

We analyze retrospectively a series of 8 patients who underwent soft tissue reconstruction of the knee area with local flaps, considering criteria and indications in the choice of each surgical option.

Main variables considered in decision-making were size and location of soft tissue defect, planned orthopaedic surgical procedure, likeliness of the need for further surgery, age, local and general condition of the patient.

Flaps employed have been medial gastrocnemius muscular flap, reverse ALT fasciocutaneous flap and the “propeller” freestyle perforator flap.

Main complications observed have been partial flap necroses and recurrence of the underlying bone infection.

In this work, the authors want to emphasize the importance of a multidisciplinary treatment of bone and prosthetic infections, where the antimicrobial therapy chosen by the Infectious Diseases Specialist must be synergic with an “orthoplastic” surgical procedure, in the effort to reduce the risk of infection persistence or recurrence and to obtain the best possible functional result and quality of life for the patient.

For decades the treatment of chronic posttraumatic osteomyelitis associated with bone exposure has been one of the most serious problems in the field of orthopedic surgery. “Sterilization” of the osteomyelitic site, that is radical debridement of all infected tissue, is the basic requirement of the treatment; in the past, the remaining defect of the debrided area was closed with skin grafts, which were removed in a further stage, when the infection was ceased; then the defect was filled with muscle flap and bone graft of various types. Both soft tissue and osseous reconstruction took a relatively long period of time requiring several-stage treatment.

We performed a retrospective study on 9 patients treated for chronic osteomyelitis of the upper limb (6 forearm – 3 arm) by means of free fibula vascularized bone graft, between 1992 and 2003 (7 male 2 female). All patients had been more than 2 previous surgical attempt with conventional treatment (sterilization and bone graft). In most of them (7 cases) a two-stage treatment was performed (resection and sterilization, eventually with muscle transfer, in the first stage and bone transfer in the second one); in other 3 cases a one-stage treatment was performed. Two cases required a composite tissue transfer with a skin pad to cover the exposure. The length of bone defect after extensive resection of necrotic bone from septic pseudoarthrosis ranged from 5 cm to 12 cm.

In all cases there was no evidence of infection recurrence in the follow-up period. The mean period to obtain radiographic bone union was 4.1 months (range 2.5–6 months). In 2 cases secondary procedures have been carried out due to an aseptic non union in one site of synthesis (cruentation and compression plate). Functional results were always satisfactory although in the forearm a complete range of motion has never been achieved (plurioperated patients with DRUJ problems).

Fibular grafts allow the use of a segment of diaphyseal bone which is structurally similar to the radius, ulna and humerus of sufficient length to reconstruct most skeletal defects. The vascularized fibular graft is indicated in patients where conventional bone grafting has failed or large bone defects, exceeding 5 cm, are observed. The application of microsurgical fibular transfers for reconstruction of the extremities allows repair of bone and soft-tissue defects when shortening is not possible with good functional results.

Background: This report presents the long term (over 20 years) experience with the use of a grit-blasted, press-fit femoral prosthesis.

Methods: The first 300 consecutive primary THA procedures using a collarless, three-dimensional tapered, straight, titanium alloy stem with a grit-blasted surface (performed in 299 patients) were evaluated up to twentytwo years. A cementless all-polyethylene socket in 80 percent of the cases, were used. Radiographic evaluation, performed by an independent observer using a zonal analysis method, included assessment of component migration, Engh’s implant-bone femoral fixation score, implant-bone demarcations, and periprosthetic osteolysis. The average duration of long-term radiographic follow-up was 12.6 years (range; 10 to 16 years).

Results: At last examination only five hips were lost to follow-up and 84 patients were deceased. The femoral revision rate was 7 percent (two hips for aseptic loosening, five hips for septic loosening, and twelve hips with osseointegrated stems for severe progressive femoral osteolysis) and the acetabular revision rate was 28% (revised for either socket migration or progressive peri-acetabular osteolysis or both). Survivorship, based on any revision (femoral or acetabular) was 89% at ten years and 65% at twenty years; survivorship of the femoral component was 95% at ten years and 89% at twenty years. The incidence of femoral periprosthetic osteolysis, was 47%, with 5% of distal endosteal osteolysis. Radiographic femoral implant-bone fixation was stable, bone-ongrowth in 97%; stable, fibrous-fixation in 1%.

Conclusions: The grit-blasted, press-fit, collarless, tapered femoral component continued to perform well clinically and radiographically up to twenty years of follow-up despite the challenging environment of peri-prosthetic osteolysis associated with the acetabular component design. This implant is still in use virtually without design modifications. This study demonstrates the durability of the results of the grit-blasted femoral component and indicates that such an implant offers a viable alternative for fixation without bone cement.

Introduction: The anatomic abnormalities associated with the dysplastic hip increase the complexity of hip arthroplasty, in addition previous femural osteotomy can deformate proximal femur.

Despite the fact that uncemented cup and stems are specifically designed for dysplasia to recover the true acetabular region in Crowe IV and sometimes Crowe III additional surgical procedure are required.

Purpose of the study is to analize surgical procedure and then reconstruction options on severe hip dysplasia.

Materials and methods: From 1984 till today 2308 cases of arthroplasty were performed in dysplastic hip, 565 cases have a previous femoral osteotomy; out of these 2308 cases 128 cases need treatment for corrections of femural side deformity.

64 cases were subjected to a greater trochanteric osteotomy. In 12 cases proximal femural shortening was associated. In 9 cases rotational abnormality and shortening were controlled with a distal femur osteotomy.

55 cases were treated by a shortening subtrochanteric osteotomy that allows corrections of any deformity. Only uncemented stems were used and in the majority of cases a specific device for displastic hip (Wagner Conus produced by Zimmer).

Discussion: Long-term results in these patients are steadily inferior to that in the general population (70% survival at 15 yrs). On femural side early failures are the reflection of learning curve and are due to insufficient fixation of the osteotomy.

Despite this, the more promising outcomes are concerning shortening subtrochanteric osteotomy with uncemented stem but only early and mid-term data are available.

Introduction In our experimental design we evaluated the osteogenic potential of h-bone marrow (hBM), h-mesenchymal stem cells (hMSC), bone morphogenetic protein (BMP-7) and the combination hMSC plus BMP-7. The aim of the study was to define the capacity to elicit bone formation of expanded hMSC alone and associated with BMP-7

Material and methods A rat femoral segmental defect model was used in this study. 12 male athymic rats were used. The institutional Animal Ethics Committee approved the study. Athymic rats test graft groups consisted of: G1-autoclaved bone and h-BM; G2-bone and h-MSC; G3-bone with BMP-7; G4-bone and h-MSC with BMP-7. h-BM aspirates were harvested from iliac crests of patients undergoing to THA. A plate has been fixed on the femurs with four cerclage wires before a femoral gap of 6mm has been realized in the diaphysis. Gap was filled with different graft. Defect was evaluated at 2, 4, 8, 12 weeks after implantation with radiographs. Evaluation of bone graft has been done using a Cook classification. Histological study with toluidine blue and safranine O at 12 weeks has been performed in each group.

Results At 8–12 weeks after surgery G1 shown non visible new bone formation, G2 minimal new disorganized bone and G3 disorganized new bone bridging graft to host at both ends. The G4 group show significant new bone and graft remodelling. Histological analysis confirmed the rx results.

Conclusion The association hMSC plus BMP-7 determines a significant activation of the osteogenic activity at 8 weeks that may have a remarkable impact on the future orthopedic surgery strategies.

It has been shown that mesenchymal stem cells (MSCs) and BMP are involved in bone formation. The aim of the study was to evaluate the osteogenic potential of human bone marrow (hBM), human expanded MSC (hexp-MSC), BMP-7, and hexp-MSC plus BMP-7, to treat a rat femoral segmental defect.

Sprague-Dawley (SD) and athymic rats (Nu) were used. SD rats where used in order to define surgical technique. Nu rats groups consisted of: G1-autoclaved bone and human bone marrow (hMNC); G2-bone and hexp-MSC; G3-bone with BMP-7 only; and G4-bone and hexp-MSC with BMP-7. A plate was attached to the femoral diaphysis with two cerclage wires. Then a 6-mm femoral gap was made and filled with a different graft. At regular intervals, the femoral defect was evaluated with radiographs, using a modified six-grade Cook classification.

At 8 weeks G1 showed non-visible new bone formation; G2 minimal new disorganised bone; G3 disorganised new bone bridging the graft to host at both ends; and G4 significant new bone and graft remodelling. Histological analysis confirmed these results.

Our results showed that although the osteogenic activity may be improved by hMSC (G2) as well as by BMP-7 (G3), the association hexp-MSC plus BMP-7(G4) produced graft osteointegration at 8 weeks after surgery. This may have a remarkable impact on future orthopaedics surgery strategies.

Human mesenchymal stem cells (hMSC), residing in the bone marrow, can be purified, expanded in cell culture and under appropriate stimuli may differentiate along the osteogenic, chondrogenic and adipogenic lineages. The aim of this study was to investigate the expansion capability and differentiation potential of MSCs obtained from femur, pelvis and acetabular cancellous bone of aged patients in order to establish whether these cells, isolated and expanded in vitro, can be used in a new approach in orthopaedic revision surgery.

In this preliminary study we enrolled 33 patients undergoing hip arthroplasty in order to investigate CFU-F frequency, expansion ability and differentiation potential of hMSC derived from three different anatomical sites: femural, pelvic and acetabular cancellous bone (ACB).

CFU-F frequency (CFU-F/10 ⁶ MNC) was 63 for pelvis (range 7–122), 90 for bone (39–132) and 47.5 for femur (7–124).CFU-F frequency was higher in ACB than in either pelvis (p=0.04) or femur (p=0.001). The patients were divided into three age groups: G1 ≤50 years (n=6), G2 50 −65 years (n=11), and G3 ≥65 years (n=16); however, CFU-F frequency did not show any statistically significant difference, although the frequency was lower at higher age.

We expanded in cell culture MSC of 16 patients from the three considered sites until the fourth passage. At the first passage there was a higher MSC recovery in ACB (median 12%) than in pelvis (median 8%; p< 0.004) and femur (median 3.8%; p< 0.0004). MSC recovery from pelvis was higher than in femur (p< 0.04). At the second and third passage MSC expansion was found to be significantly higher in ACB than in pelvis alone (median 3.1 vs 1.6, p< 0.01; 1.8 vs 1.2, p< 0.005, respectively), while at the fourth passage it became higher than in pelvis and femur (median 2.6 vs 1.4, p< 0.03; 2.6 vs 1.6, p< 0.0, respectively). At each culture passage, cells showed MSC features as supported by flow cytometry and by the multilineage differentiation potential.

hMSCs seem to have higher frequency in close association with bone; moreover, they show an increased expansion ability in vitro which is still mantained in elderly patients. As these progenitors can differentiate in bone, they seem to be the best choice for the effective repair of bone defects in revision surgery.

Aims: The purpose of this study is to review eight to eleven year results of a consecutive series of primary hybrid total hip arthroplasties. Methods: 193 patients (197 hips) received a cemented, polished, collarless, femoral component (Ra=1) in association with an uncemented acetabular component (166 grit-blasted titanium ßexible, 17 Ti mesh, and 14 Standard porous cups). Results: Mean age at surgery was 69.5 years (51–90). Most frequent diagnosis was osteoarthritis. Average follow-up was 9.2 years (8.5 to 11.2). 21 patients (23 hips) were lost to follow-up. 24 patients (25 hips) died prior to eight-years and none had undergone revision. Two femoral components, the only two with Grade D cement mantles, were revised for aseptic loosening at 23 and 111mos. One Ti mesh socket was revised for catastrophic poly wear at 113m and one ßexible cup for dislocation at 111m. The remaining 146 stems and cups were available for minimum 8year clinical review. 62 underwent complete radiographic review. Conclusions: Post-op Harris score was 89.3 (68–100). Pain relief was good or excellent in 95% of patients. X-rays revealed 1–2mm of femoral subsidence in 6 hips. Two cases of proximal (zones 7 and 1) femoral osteolysis were identiþed. A cemented polished femoral component and an uncemented acetabulum provide excellent clinical and radiographic results at average 9y follow up. Continued success appears likely in the absence of osteolysis or cement bone demarcation.