Femoral revision with the modular ZMR stem. Clinical and x-rays results at medium term follow-up

A retrospective review was conducted to evaluate the medium-term results of the ZMR modular revision taper stem. From March 1999 to December 2002, 65 consecutive hip revision surgeries were performed mostly for aseptic loosening. Femoral bone stock defects were classified according to AAOS\u2019s criteria and consisted mainly in type II and type III. A Wagner osteotomy was performed in 25 cases to remove primary implants that were cemented in 35 cases. Mean post-operative follow-up was 69 months (range, 36 to 91months). Clinical assessment at follow-up showed a significantly improved mean Harris Hip Score from 42 points preoperatively to 81 points postoperatively, while the x-ray examination did show a satisfactory distal integration of the stem in all cases and satisfactory reconstitution of the femoral bone stock in 47% of cases. The average subsidence of the stem at follow-up was under one millimeter. According to the data leg length discrepancy exceeding 15 millimeters caused significantly higher functional impairment and more pain

Lateral parapatellar approach in primary total knee arthroplasty of the valgus knee

Background Anatomic and pathological characteristics of the valgus knee deformity represent a challenging issue for the implant of a total knee arthroplasty. The surgical approach in such cases should allow a direct ad easy exposure of the joint, easy lateral soft tissue balancing and adequate patellar tracking. Materials and Methods Twenty-four total knee arthroplasties were implanted in valgus knees between January 2002 and September 2005. A mean preoperative valgus deformity of 18\ub0 was assessed on standing x-rays. Four posterior stabilized, eighteen posterior stabilized rotating platform prosthesis and two superstabilized prosthesis were implanted in 21 patients. The surgical approach has been in all cases a lateral parapatellectomy. Follow-up assessments were obtained for all patients at a mean 23 months. They consisted of a Knee Society Score and a Patellar Score evaluation, standing AP and lateral radiograms and skyline x-rays obtained at a flection of 45\ub0. Results A mean preoperative Knee Society Clinical Score of 32,7 points (range, -4 to 64 points) significantly improved at follow-up to an average 88,8 points (range, 57 to 99 points; p<0,05). The Knee Society Function Score significantly increased from a preoperative mean score of 32,7 points (range, -20 to 75 points) to an average followup score of 81,2 points (range, 30 to 100 points; p<0.05). The Patella Score revealed absence of anterior pain in all cases but one that reported severe pain. A satisfactory patello-femoral alignement of 4.7\ub0 (range, 1\ub0 to 10\ub0) was obtained at last follow-up x-rays. One intraoperative condilar fracture occured and was treated with a single screw. Discussion The lateral approach of valgus knees led to satisfactory results in primary total knee arthroplasties in a percentage of cases comparable or superior to those presented in literature for different approaches. In addition, lateral release is performed as a part of the approach itself, allows preservation of the blood supplies of the extensor apparatus and an optimal patellar tracking in most cases. Conclusions In conclusion, the lateral approach for a primary total knee arthroplasty could be recommended in valgus knees affected by osteoarthritis because as it proved to be effective in achieving a satisfactory implant positioning and functional outcome while reporting minor complications

Treatment of periprosthetic femoral fractures with distal fixation modular revision stems

Background Late periprosthetic fractures of the femur are the third most frequently reported cause of surgery after total hip artroplasty. Revision total hip artroplasty can be difficult, especially when poor bone stock is encountered. The aim of this study was to examine the results of late periprosthetic fractures complicated with primary implant loosening performed with distal fixation modular revision stem. Methods From November 1999 to May 2006, 16 late periprosthetic fractures were treated with distal-fixation, modular, straight stem. There were 13 females (82%) and 3 males (18%) whose mean age at surgery was 76.7 years (range, 48 to 95 years). Femoral revision surgery was performed with the Revitan (2 cases) and ZMR (14 cases) to get a stable distal primary fixation. X-rays were assessed accordingly to the Vancouver classification: there were 3 type B2 and 13 type B3 fractures. Mean post-operative follow-up was 52 months (range, 10 to 88 months). At the time of the last follow-up visit 4 patients already passed away, all of them for causes unrelated to the procedure. The clinical outcome was monitored with the Harris Hip Score, subjective VAS, pain and satisfaction evaluation. Standard AP and lateral x-rays of the hip were obtained at each follow-up visit. Leg-length discrepancy was also investigated as a factor possibly affecting outcome. Complications included one septic loosening that was treated with a two-stage revision. Results All the patients but one were finally able to walk and had minimal to no pain at all. A satisfactory functional outcome was achieved with an average 76 (range, 25 to 100) Harris Hip Scores points. The subjective pain and satisfaction scores were respectively 2.4 and 7.8 points. As far as radiograms are concerned, all the sixteen femur did show a good healing of the fracture, with no secondary stem subsidence. Discussion Generally, considering the severity of an event such as a periprosthetic late fracture in an elderly patient, results were satisfactory. The average Harris Hip Score and subjective satisfaction would have been even higher if one patient wouldn\u2019t have been so much disappointed because of her severe leg-length discrepancy, dependent on the acetabular side. From a surgical point of view, the employed devices proved to be handy in bridging the fracture with distal fixation while adequately stabilizing it. Conclusions According to the reported results, straight modular-revison stems provide an adequate treatment option of Vancouver type B3 and in selected cases of B2 type periprosthetic femoral fracture

Radiological evaluation of the metal-bone interface of a porous tantalum acetabular component

Introduction Porous tantalum presents a bone-matched elastic modulus and an high coefficient of friction on cancellous and cortical bone. Furthermore, its open-cell tantalum structure of repeating dodecahedrons, similar to cancellous bone, should be favourable for bone ingrowth. These physical and mechanical properties should increase primary fixation and potential osteointegration of acetabular cups and should decrease periacetabular stress shielding. The purpose of this study was to radiographically evaluate the evolution of the metal-bone interface of porous tantalum acetabular components. Materials and Methods Serial radiographic evaluation of 41porous tantalum acetabular component has been performed in 40 patients. Twelve hips underwent total hip arthroplasty using a trabecular metal monoblock acetabular component and 29 hips using a trabecular metal modular acetabular system. All patients were clinically and radiographically evaluated at four, eight, 12, 24 weeks, 12 months and then annually. All cases were available for a minimum follow-up of two years (mean 35 months). On post-operative x-rays the metal-bone interface was investigated for areas in which the porous surface of the acetabular component was not in contact with bone. These gaps were measured and classified by location according to DeLee and Charnley zones. Evolution of postoperative gaps, presence of lysis or periacetabular radiolucencies and component migration were assessed during follow-up. Results On post-operative x-rays 36 components (88%) had a gap between the outer surface and the host bone but only in 12 cases (29%) gaps were larger then 1 mm. The gaps were mostly situated in the polar region (zone II) when compared with the peripheral zones and no one was bigger then 5 mm in width. At last follow-up 23 (64%) of the initial gaps were no longer radiographically evident, 10 (28%) had a favourable evolution and appeared reduced in dimension but still present and 3 (8%) didn\u2019t fill at all and were unchanged when compared with post-operative controls. There was no progression progression of any post-operative gap and no evidence of new periacetabular radiolucent lines or lysis. No acetabular implant showed evidence of migration or needed revision for loosening. At last follow up the mean Harris Hip Score was 95. There were no dislocation or other complications. Discussion Short term results with porous tantalum acetabular component are encouraging: the bridging of the interface gaps and the absence of periacetabular radiolucencies indicate good mechanical and osteoconductive properties. Further follow-up will be required to confirm these results in the long term

Acetabular revision surgery in the presence of severe bone loss: surgical technique and early results with modular porous tantalum augments and cups

Subject: In the presence of minimal acetabular bone loss most revision procedures can be done with the use of an uncemented hemispheric device with or without morselized allograft. The use of modular porous tantalum augments and cups has been recently introduced to address more severe bone deficiencies. The purpose of this study is to describe the surgical technique and early clinical results obtained with trabecular metal acetabular augments in cases of acetabular revision with severe bone loss. Materials and Methods: Since November 2003 seven acetabular revisions have been done by means of TMT\uae augments and cups: the primary indication for acetabular revision was aseptic loosening in five patients and septic loosening in two patients. According to Paprosky classification the acetabular bone defects were classified as follows: 2B in two hips, 2C in one hip, 3A in two hips and 3B in three hips. In two cases it was the first surgical hip replacement procedure. Five cases were multiple revisions. Results: At an average follow-up of 24 months no implant had evidence of loosening or migration. No dislocations occurred. Discussions and Conclusions: Augments provide mechanical support to hemispheric cups of various dimensions. This surgical technique avoids the use of structural allograft, helps to restore the center of hip rotation and increases contact area between the implant and the host bone for biological fixation. Longer follow-up is required to verify survival of these implants and potential mechanical and biologic complications related to use of this modular TMT\uae system

The Use of Modularity in Total Hip Arthroplasty

Modularity is defined as separation of a system into independent parts or modules that can be treated as logical and may be separated and recombined. Historically, the modularity represents the evolution of the concept of "low friction arthroplasty" developed by Sir J. Charnely in 1960. The disadvantage of a one-piece stem is the difficulty of restoring the biomechanical feature of the hip. Thus, the natural evolution was the introduction of modularity on both sides, the acetabulum and the femur. Modularity allows the surgeon to accurately match the anatomic characteristics of each patient to obtain improved range of motion, joint stability, abductor strength, and leg length equality. Disadvantages are related to the introduction of different interfaces, which could be sites of wear and corrosion. In accordance with the most recent literature, in primary total hip arthroplasty (THA) the modularity can be reduced to the head and the acetabular component, while a one-piece stem can manage the majority of cases. On the other hand, we believe that during revision surgery, a complete modularity is necessary

ANTERIOR LONGITUDINAL OSTEOTOMY OF THE GREATER TROCHANTER IN TOTAL HIP ARTHROPLASTY: SHORT-TERM FOLLOW-UP

BACKGROUND Early dislocation is a foremost complication of total hip arthroplasty through a postero-lateral approach. The extra-articular impingement of the anterior part of the great trochanter with ileum bone, with or without soft tissue interposition is a well recognized but underestimated etiopathogenetic cause reported in literature. In this retrospective study through the assessment of clinical and radiographic follow-up at a minimum of six months, the effectiveness of an antero- longitudinal osteotomy of the great trochanter for early dislocation prevention is evaluated. MATERIALS AND METHODS 209 patients (48.3% males and 51,7% females) underwent a total hip arthroplasty from June 2011 to September 2015, with surgery being performed by the same surgeon. A modified posterolateral approach was used according to the tissue-sparing criteria, in all the cases an anterior longitudinal osteotomy of the great trochanter has been performed at 90\ub0 to the antiversion angle of the implant and aligned posteriorly with the prosthesis. All the patients underwent a clinical and radiological follow up at one, three, and six months. RESULTS In this study, only one patient reported dislocation of THA. One patient suffered from a wound infection which was subsequently treated with antibiotics and had complete remission. All patients demonstrated a fast recovery of ROM and walking, starting from pre-op Harris Hip Score 42.24pts and obtaining a score of 81.52pts at three months, and 92.03 at six months post-op. After surgery and during the follow up period, there were no trochanteric fractures detected. DISCUSSION The correct positioning of the implants, the head diameter, offset, soft tissues repair, absence of impingement, and patients compliance are all elements that define the prosthetic stability. Literature shows and incidence of primary total hip arthroplasty dislocation between 0.80% to 10%. The incidence of dislocation reported in a preliminary study in our Institute is 0.48%, demonstrating the effectiveness of the trochanteric osteotomy. CONCLUSIONS The osteotomy of the great trochanter is an effective surgical technique used to decrease the anterior impingement and early dislocation incidence. It is particularly effective on patients with good compliance and correctly implanted prosthetic components

I FANS NELLE PATOLOGIE MUSCOLOSCHELETRICHE: FORME FARMACEUTICHE A CONFRONTO

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