Aim

In surgeries on patients with advanced ligament instabilities or severe bone defects modern-generation of rotating hinged knee prostheses are one of the main options. The objective of our study is to evaluate the mid-term functional results and complications of several surgeries using this form of prosthesis.

Managing severe acetabular bone defects during primary and revision total hip arthroplasty is a challenging problem. Standard treatment options for this cases is using of acetabular reconstruction type-Burch-Schneider rings. Unfortunately, the possibility of osseointegration of these implants with surrounding bone has always remained a contentious issue. The emergence in recent years of new designs of trabecular titanium, representing a symbiosis of acetabular reconstructive plates and modular cup helped to solve this problem on a completely new level.

The aim of this prospective study is to evaluate the short and mid-term clinical and radiographic outcomes of different types of acetabular revision cups - old and new design.

From 2006 to 2015, we performed 48 acetabular reconstruction with reconstruction rings CONTUR Smith and Nephew(group 1) and 34 operations with Delta TT Lima Revision system (group 2). The mean age of patients was 59.2 years (range 30–79). Indications for operations included fractures in acetabular region (10 pat – 12,2 %), acetabular nonunions with bone defects (14 pat – 17,1%), aseptic loosening with multiple dislocation of the primary implants in 38 cases (46,3%) and second stage of infection treatment in 20 cases (24.4%). Clinical and functional outcomes were evaluated by Harris Hip Score (HHS). Bone density in Charnley's zones was measured by dual-energy x-ray absorptiometry.

With CONTUR reconstruction rings were used 3 different types of bearing surface articulation (22 metal/polyethylene, 10 ceramic/polyethylene, and 16 oxinium/polyethylenel). With Delta TT Revision system were used metal/poly couples in 22 cases, ceramic/poly in 6 cases, and ceramic/ceramic couple in 4 cases. In two patients with high risk of dislocations were used double mobility system.

In all operations with CONTUR rings was used bone impaction grafting to fill cavitary defects (Paprosky 2B-3A), with Delta TT Revision system in 14 cases (41,2%) additionally TT augments were used.

In group 1 were 3 dislocations (6,3 %), 2 deep infections (4,2 %) and 4 aceptic loosenings with secondary instability of implants (8,3 %). In group 2 Trabecular Titanium showed a high capacity of osseointegration, providing good results in short-term follow-up. We registered only 2 dislocations (5,8 %) and 1 aceptic loosening (2,9 %). The mean HHS increased from 39.7 (range 23–62) preoperatively to 86.5 (range 68–98) at the last follow-up examination. The implanted cups were radiographically stable at the last follow-up visit (1 and 2 years) without radiolucent lines or periprosthetic osteolysis.

Modern prosthetic stem construction strives to achieve the attractive goals of stress shielding prevention and optimal osteointegration. PhysioLogic stem is a new generation composite isoelastic femoral stem consisting of titanium core sheathed in implantable PEEK polymer and coated with titanium layer. This construction combines the benefits of both stress shielding prevention, due to its elasticity under bending load corresponding closely to that of natural bone, and rapid osteointegration, due to the stem's titanium coating.

The aim of this study is long-term clinical progress evaluation and retrospective analysis in patients undergoing primary PhysioLogic stem implantation at our institution.

From 1998 to 2003, we performed 51 primary total hip arthroplasty (THA) operations with implantation of PhysioLogic Stem at our institution. Indications for THA included osteoarthritis (21), hip dysplasia (14), rheumatoid arthritis (10), and femoral neck nonunion (6). In all patients we used totally uncemented system — PhysioLogic Stem and monoblock cup with different types of bearing surface articulation (40 metal/polyethylene, 3 ceramic/polyethylene, and 8 metal/metal). In all cases head size was 28mm. Two patients died in the early post-op period at day 1 and day 9 from disseminated intravascular coagulation and pulmonary embolism, respectively, and were excluded from subsequent analysis. Analyzed patients included 20 women and 29 men; median age 45, range 21–69. Post-operatively, the patients were evaluated at 3 and 6 months, 1 year, and yearly thereafter. Median follow-up period was 14 years, range 11 to 16 years. Clinical and functional outcomes were evaluated by Harris Hip Score. Bone density in Gruen's and Charnley's zones was measured by dual-energy x-ray absorptiometry.

Four patients died at 5–8 years postoperatively from cardiac causes. Two patients underwent revision surgery: one patient underwent “dry revision” due to hip dislocation with exchange for longer head while keeping the original PhysioLogic stem in place; second patient underwent stem removal after chronic periprosthetic infection. Among the 45 patients with surviving PhysioLogic Stem, 33 patients (75%) underwent subsequent contralateral total hip arthroplasty with standard uncemented stems types Spotorno or Zweymuller. These patients were surveyed at postoperative evaluation about subjective comparative performance of PhysioLogic Stem versus standard stem. Twenty seven patients (82%) reported the PhysioLogic stem to be equivalent or superior to the standard stem, with 15 patients (45%) rating the PhysioLogic stem as subjectively more comfortable than the standard stem.

The average Harris hip score improved from 40 points preoperatively (range 27 to 48) to 93 points (range 89 to 95) at the time of final follow-up. All stems continue to show adequate bone-ingrown fixation with no radiological signs of aseptic loosening to date. The PhysioLogic stem removed in the aforementioned case of chronic periprosthetic infection also showed clear signs of good osteointegration.

Our study showed that the PhysioLogic stem implantation resulted in favorable clinical and functional performance at long-term follow-up, making it an attractive alternative to standard stems.