Peripheral snap-fit locking mechanisms and smooth surface finish of tibial trays reduce backside wear in fixed-bearing total knee arthroplasty.

Background and purpose - Severe backside wear, observed in older generations of total knee replacements (TKRs), led to redesign of locking mechanisms to reduce micromotions between tibial tray and inlay. Since little is known about whether this effectively reduces backside wear in modern designs, we examined backside damage in retrievals of various contemporary fixed-bearing TKRs. Patients and methods - A consecutive series of 102 inlays with a peripheral (Stryker Triathlon, Stryker Scorpio, DePuy PFC Sigma, Aesculap Search Evolution) or dovetail locking mechanism (Zimmer NexGen, Smith and Nephew Genesis II) was examined. Articular and backside surface damage was evaluated using the semiquantitative Hood scale. Inlays were examined using scanning electron microscopy (SEM) to determine backside wear mechanisms. Results - Mean Hood scores for articular (A) and backside (B) surfaces were similar in most implants-Triathlon (A: 46, B: 22), Genesis II (A: 55, B: 24), Scorpio (A: 57, B: 24), PFC (A: 52, B: 20); Search (A: 56, B: 24)-except the NexGen knee (A: 57, B: 60), which had statistically significantly higher backside wear scores. SEM studies showed backside damage caused by abrasion related to micromotion in designs with dovetail locking mechanisms, especially in the unpolished NexGen trays. In implants with peripheral liner locking mechanism, there were no signs of micromotion or abrasion. Instead, "tray transfer" of polyethylene and flattening of machining was observed. Interpretation - Although this retrieval study may not represent well-functioning TKRs, we found that a smooth surface finish and a peripheral locking mechanism reduce backside wear in vivo, but further studies are required to determine whether this actually leads to reduced osteolysis and lower failure rates.

Massive failure of TiNbN coating in surface engineered metal-on-metal hip arthroplasty: Retrieval analysis.

This article presents examination of a failed total hip replacement with surface engineered metal-on-metal (MoM) articulation. The implant was coated with a thin TiNbN film (Physical Vapor Deposition), and at retrieval 53 months after implantation the coating was abraded on weight-bearing part of the head and acetabular component. Scanning electron microscopy of bearing surfaces demonstrated multifocal crack formation, delamination of small film fragments, and formation of aggregates containing nanometer sized wear debris. We also observed coating damage in third body mechanism. Complex failure mechanism of TiNbN coating demonstrated in this study suggests insufficient bonding strength between the coating and substrate alloy and raise concerns regarding the use of such coatings in total hip arthroplasty with MoM bearing. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1043-1049, 2016.

Retrieval analysis of titanium nitride (TiN) coated prosthetic femoral heads articulating with polyethylene.

Data regarding in vivo performance of titanium nitride (TiN) coated prosthetic femoral heads is scarce, and available studies of older generations of implants demonstrated coating wear in vivo. That is why we conducted a retrieval analysis of 11 femoral heads (articulating in vivo for 1-56 months) with TiN film formed using physical vapor deposition (PVD), to verify if coating failure is a problem in contemporary implants. Retrieved implants were examined using scanning electron microscope, coating roughness was evaluated with a contact profilometer and adhesion was tested using a Rockwell HRC test according to VDI 3824 guideline. Although no gross failure of the TiN coating was observed in our retrievals, all implants had defects typical for PVD coatings, such as pinholes, small titanium droplets and blisters with delaminated coating. In some heads the coating was contaminated with small niobium (Nb) droplets uniformly scattered on the entire surface of the film. Presence of Nb contamination was associated with an increased number and area of other types of defects and poorer coating adhesion. In one component, subjected to multiple dislocations we found severe delamination and cracking of the coating, increased roughness and the presence of third bodies. Our results indicate, that although wear of the coating is lower than seen in older generations of implants, inconsistent quality of the TiN film among different implants indicates the need for strict monitoring of the manufacturing process.

Remodeling of bone tissue around the distal part of Zweymüller stem.

BACKGROUND: The Zweymüller stem is well-known in Europe and widely used for total hip replacement since 1980. Few authors have noted the presence of increased bone density below the tip of the stem; however, the underlying mechanism is still unknown. The aim of this study was to reveal factors influencing bone remodeling around the tip of the Zweymüller stem. MATERIAL AND METHODS: 102 consecutive patients (69 women and 33 men) who received a second generation Zweymüller type stem (123 prostheses) were included. Mean follow-up was 9.2 years (6 - 15 years). A Cortical Index (CI) was defined as the ratio between stem width and external cortical diameter in Gruen zones 3 and 5. RESULTS: Patients with a wide femoral canal and thin cortical bone (CI ≥0.4) demonstrated a positive correlation with the presence of increased bone density (IBD) below the stem (p<0.0001, r=0.6028). During follow-up, the mean Cortical Index decreased by 0.02 points and mean thickness of cortical bone in zone 3 and 5 increased by 2.0 millimeters. Cortical thickening was more pronounced in cases without IBD (1.5 vs. 2.4 mm, p=0.0172). CONCLUSIONS: 1. Thin cortical layers and a wide femoral canal (CI ≥0.4) can result in the presence of IBD below the stem. 2. IBDs probably appear due to mechanical stress transferred by the tip of stem to cancellous bone in Gruen zone 4. 3. Based on clinical symptoms, we conclude that the presence of IBD is not associated with increased aseptic loosening or stem instability.

Knee Function and Subjective Stability Following Total Condylar Arthroplasty in Joints with Preoperative Varus or Valgus Deformity.

BACKGROUND: Total knee arthroplasty in joints with valgus or varus deformity is technically demanding. Careful soft tissue balance as well as restitution of anatomical knee axis has a profound effect on postoperative function of the joint, however little is known about differences in subjective stability following surgery between preoperative valgus and varus knees. MATERIAL AND METHODS: Studied group consisted of 60 patients who underwent total condylar knee arthroplasty with one type of implant (Stryker Triathlon). Mean follow-up was 2,9 years (1-6 years). The group included 25 patients with valgus and 35 patients with varus preoperative deformity. All patients filled Knee Injury and Osteoarthritis Outcome Score (KOOS) forms. Detailed clinical and radiological assessment was performed. RESULTS: Mean KOOS score was slightly higher in patients with varus deformity, as compared to cases with valgus deformity. At physical examination higher LCL deficiency rate was observed in varus knees. Subjective instability was reported by eight patients (5 valgus and 3 varus). In all cases instability coexisted with decreased MCL tightness and implant position was correct in those patients. No subjective instability was reported by patients with clinical LCL deficiency. Furthermore KOOS scores in these patients were higher (85,8) as compared to cases with decreased MCL tension (79,1). CONCLUSIONS: 1. In patients with proper implant alignment subjective instability is related to postoperative MCL deficiency, regardless preoperative deformity in coronal plane. 2. The post-op LCL laxity does not compromise subjective stability, nor influence subjective outcome, as demonstrated with KOOS scores.

Lymphorrhoea as an early complication after decompression of C5 and C6 roots through scalenotomy. Successful treatment with VATS preceded by conservative treatment.

Lymphorrhoea is a rare complication after orthopaedic surgeries. This paper presents a case of a patient who demonstrated cervical lymphorrhoea as an early complication of scalenotomy. The lymphorrhoea was success - fully stopped through VATS closure of the thoracic duct following initial ineffective conservative treatment.

Impact of athletic activity on the stability of the lower limb joint prosthesis.

This publication analyses the impact of athletic activity on the stability of lower leg implant. Analysis of literature does not allow for a clear answer whether such activity is an independent predictor of early loosening. Number of publications warning patients against excessive sports activities, equals the number of reassuring reports.

Debonding of porous coating of a threaded acetabular component: retrieval analysis.

This report presents a case of debonding of plasma sprayed porous titanium coating from a threaded acetabular component which caused aseptic loosening of the implant. Weight bearing after delamination caused abrasive damage of the acetabular shell, and particles of the coating embedded in the acetabular liner. Microscopic examination of periprosthetic tissues showed presence of metal particles and macrophage infiltration. Despite microscopic examination of the retrieved component the cause of debonding remains unclear.

30-year survival of a McKee-Farrar hip prosthesis--case report and microscopic analysis of bearing surface.

We report a case of a female patient using a McKee-Farrar prosthesis for 30 years, until revision surgery for aseptic loosening. Electron microscopy analysis of bearing surface of the retrieved implant was performed, and the results were presented in comparison with previously published papers.

[Assessment of the level of metal ions in the blood of patients after hip resurfacing--preliminary report]. / Ocena poziomu jonów metali we krwi pacjentów po endoprotezoplastyce powierzchniowej--doniesienie wstepne.

INTRODUCTION: Metal-on-metal bearings characterize lower wear than metal-poly, lower fracture risk than ceramics and they allow for the manufacturing of large diameter heads. The metal ion release from the bearings is the the major concern of these articulations. MATERIAL: The study group consisted of 16 patients who underwent hip resurfacing with Durom implant and had minimum 1 year follow-up period. Blood from the patients was collected 4 times: before the surgery, 2, 6 and 12 months postoperatively. METHODS: Clinical examination was done according to HHS, Radiographic image was used to measure the cup inclination, evaluation of chromium and cobalt ion blood levels was performed using graphite furnace atomic absorbtion spectrometry (GFAAS). RESULTS: The levels of cobalt and chromium increased postoperatively significantly to decrease slightly at 6 months. At 1 year cobalt levels increased to the similar level like at at 2 months. The chromium level decresed to the values as low as preoperatively. The mean cup inclination angle measured on X-rays was 48 degrees(range 39 degrees - 56 degrees). The mean HHS result was 89.86 (range 64.43 to 98.73). The mean activity level measured with UCLA scale was 6 (range 3-9). CONCLUSIONS: The metal ion blond levels increase sigficantly in the period 2-6 months following hip replacement with large diameter metal-on-metal articulation. In further examinations at 1 year post-op ion levels decrease.

[Porous tantalum modular cups in revision hip arthroplasty]. / Zastosowanie modularnych komponentów z porowatego tantalu w endoprotezoplastyce rewizyjnej panewki stawu biodrowego.

INTRODUCTION: Modem indications for use of cemented or uncemented implants in revision hip arthroplasty are comparable. The use of bone cement provides predictable short term results, but the lack of osteointegration deteriorates its long term durability. Uncemented implants undergo osteointegration, but reduced contact with host bone may cause early loosening. Modular porous tantalum implants are highly osteointegrative, and the availability of bone stock augments increases the versatility of this system. MATERIAL AND METHODS: The study group consisted of 20 patients (21 hips) who underwent a revision hip arthroplasty using Trabecular Metal acetabular revision system. The follow-up period was between 7 and 31 months (average 20 months). All patients were evaluated with HHS and conventional radiography. RESULTS: The mean HHS increased form40.45 (range 18.74-56.65) preoperatively to 78.8 (56.5-96) at the last follow-up. No mechanical failures, nor septic complications were noted.

[Reactions of bone tissue around the ABG II stem]. / Reakcje tkanki kostnej wokól trzpienia endoprotezy ABG II.

UNLABELLED: The uncemented total hip replacement became a standard in treatment of the severe hip osteoarthritis. Its long term efficiency is based on the correct osteointegration which depends on the adequate implantation. Material. The study group consisted of 49 patients (52 hips) following total hip replacement with ABG II stem and Trident PSL cup. The follow-up ranged between 6 months and 2 years. METHODS: In each case the Harris hip score was performed and high resolution x-rays were taken. On X-ray the fit and position of the stem, linear osteolysis around the stem and bone atrophy at the greater trochanter were evaluated. Results. The mean HHS at the last follow up was 90.4 (50-99). The mean angle of the stem position was 2.9 varus. The mean fit index was was 0.75. The significant correlation was found between the fit index and the varus stem position angle. The linear osteolysis surrounding the stemin the 1st Gruen zone was found in 70% of cases. The phenomenon of the linear radiolucenecy surrounded by linear densification was found in the 76% of cases. Bone atrophy at the greater trochanter was found in the 42% of cases. Conclusions. The use of ABG II stems provided very good clinical results. The stem has a tendency to a varus position, which seems to be connected with the use of the too small stems. Specific radiographic observations create a need of futher follow-up, but existed without the influence on the clinical results.

[Total knee replacement in joints with severe varus and bone deficiency]. / Endoprotezoplastyka stawu kolanowego ze znaczna szpotawoscia i deficytem kostnym.

INTRODUCTION: Total knee replacement in knees with severe valgus and defects of the medial tibial condyle are at higher risk complications than in knees with a correct axial allignement. MATERIAL AND METHODS: The study group included 10 patients (11 knees) with with severe valgus and defects of the medial tibial condyle in which TKR was performed. In 8 cases bone defects were filled with bone autograft in 3 cases defects were filled with metal augments. The mean follow-up was 37 months (26 months to 4 years). Clinical results were measured with the knee society score, the level of activity was evaluated with the UCLA score. Radiographic evaluation was based on radiograms taken preoperatively, postoperatively and at the follow-up examination. RESULTS: In All cases an improvement in clinical results was noted, the mean KSS result rised from 25.3 preoperatively to 87 postoperatively and the level of activity rised from 3.4 to 5.4 postoperatively. No signs of loosening were found in radiographic evaluation. CONCLUSIONS: TKR in joint with severe varus and medial tibial condyle defects creates a need for the reconstruction of defects. In lesser defects reconstruction with bone autografts is sufficient, in severe cases filling the defect with metal augments is needed. When indicitions are followed both methods provide good clinical results.

[Current views on the pathogenesis of osteoarthritis]. / Wspólczesne poglady na patogeneze choroby zwyrodnieniowej stawów.

Degenerative joint disease is the most common joint pathology and the main cause of disability of elderly people in developed countries. It is caused by imbalance between degeneration and regeneration of articular cartilage accompanied by pathological changes of other joint structures. No generally recognizable description of the pathogenetic pathway of osteoarthritis (OA) exists so far, however recent studies have widened the knowledge of the underlying pathology. In this review views regarding the role of genetic and mechanical factors in OA pathogenesis were presented. The role of pro-inflammatory mediators such as cytokines (IL-1, TNF-alfa, IL-6), lipid mediators, NO, reactive oxygen species, were discussed. The contribution of adipokines (fat tissue derived hormones with cytokine activity) to the pathogenesis of degenerative joint disease was also described. The role of synovial membrane, articular cartilage, subchondral bone and such structures as osteophytes and infrapatellar fat pad in development of osteoarthritis were presented as well.

Early acute phase response following total hip replacement.

BACKGROUND: The acute phase proteins are commonly known universal markers of the inflammatory process. The aim of the study was the evaluation of the acute phase response in the first 6 months THR. The secondary aim was to check if the type of hip replacement affects the acute phase response. MATERIAL AND METHODS: The study group consisted of 40 patients who underwent THA using uncemented (20) and cemented (20) endoprostheses. The concentrations of C-reactive protein, alpha-glycoprotein, and alpha-1-antichymotripsin, and microheterogeneity of AGP were evaluated. RESULTS: The blood levels of the acute phase proteins CRP, AGP, ACT rose significantly at 2 and 14 days after the surgery to return to preoperative values at 6 months after the surgery. The V3 variant of microheterogeneity of AGP, absent under normal conditions, and representative of acute inflammation, was found in a few patients preoperatively. In postoperative evaluations, it was found in the vast majority of the patients. CONCLUSIONS: The analysis of the profiles of the glycosylation of AGP shows that the presence of the acute inflammatory response immediately following total hip replacement, which later changes into persistent chronic inflammation, is more pronounced in patients receiving cemented endoprosthesis.

[Physical activity and quality of life following total uncemented hip replacement and hip resurfacing]. / Aktywnosc fizyczna i jakosc zycia po endoprotezoplastyce bezcementowej oraz kapoplastyce stawu biodrowego.

INTRODUCTION: The influence of physical activity on the survival of total hip replacement remains not fully recognized. It is unclear which activities are beneficient for patients following THR. MATERIAL: The study was conducted on group of 87 patients (94 hips) following uncemented THR with ABGII/Trident and 45 patients (51 hips) following hip resurfacing. The follow-up period was 6-30 months for THR group and 6-42 months for resurfacing group. METHODS: The patients answered a questionnaire based on WOMAC and SF-36 score, UCLA activity scale with additional questions concerning patients physical activity, working and place of living. RESULTS: In WOMAC, physical domains of SF-36 and UCLA activity score patients following hip resurfacing showed better results. The most preferred activity in both groups was exercise walking and biking. The last one was particularly preferred by patients living in rural areas. CONCLUSION: The vast majority of patients restricted their activity to disciplines with a safe range of hip weight bearing.