Clinical and radiographic evaluation of total hip arthroplasties using porous tantalum modular acetabular components: 5-year follow-up of clinical trial

Effects of porous tantalum on periprosthetic bone remodeling around metaphyseal filling femoral stem: a multicenter, prospective, randomized controlled study

Periprosthetic bone loss due to adaptive bone remodeling is an important unresolved issue in cementless total hip arthroplasty (THA). The use of porous tantalum on the proximal surface of the femoral stem is expected to decrease postoperative bone loss around the prosthesis through early fixation. We conducted a multicenter randomized controlled study to determine if porous tantalum could reduce periprosthetic bone loss after THA. From October 2012 to September 2014, 118 patients (mean age, 61.5 years; 107 females and 11 males) were prospectively enrolled and were randomly allocated at a ratio of 1:1 to either a metaphyseal filling stem with a proximal porous tantalum coating (Trabecular Metal) or a conventional metaphyseal filling stem with fiber mesh coating (VerSys). Patients underwent dual-energy x-ray absorptiometry scans within 1 week after surgery (baseline) and at 6, 12, and 24 months after surgery to assess periprosthetic bone mineral density (BMD) in the 7 Gruen zones. In addition, the Japanese Orthopaedic Association hip score was assessed before surgery and at 6, 12, and 24 months after surgery. In the proximal periprosthetic region (zones 1 and 7), the Trabecular Metal group had significantly smaller reductions in BMD than the VerSys group throughout the study period. In the VerSys group, significant reductions in BMD compared to baseline were seen at each measurement point in all regions, except in zone 6 at 24 months. In the Trabecular Metal group, no significant reductions in BMD relative to baseline were seen in zones 1, 5, or 6 throughout the study period. Both groups demonstrated similar improvement in Japanese Orthopaedic Association hip scores over the study period. This study demonstrated that a proximally coated stem with porous tantalum has superior results over a conventional stem with titanium fiber mesh in terms of periprosthetic bone remodeling.

Total hip arthroplasty after periacetabular osteotomy versus primary total hip arthroplasty: a propensity-matched cohort study

BACKGROUND

Controversy still exist regarding the outcomes of total hip arthroplasty (THA) after periacetabular osteotomy (PAO). The purpose of this study was to compare the clinical and radiologic outcomes of THA after PAO with primary THA based on balanced baseline characteristics with propensity score matching.

METHODS

Using propensity score matching, 1:2 matched cohort to facilitate comparison between patients who underwent primary cementless THA with or without previous PAO. Then, we compared the operative time, blood loss, complications, postoperative clinical score, cup size, position, and alignment of acetabular cup, and degree of bony coverage on cup between the two groups.

RESULTS

Thirty-five patients with 37 hips who underwent THA after PAO were successfully matched to 70 patients with 74 hips who underwent primary THA. The operative time and blood loss in THA after PAO were significantly longer and larger than those in primary THA (P < 0.001 and = 0.0067, respectively). Clinical score showed no difference between the groups (P > 0.05). For THA after PAO, the cup size and bony coverage were larger (P = 0.0014 and < 0.001, respectively), and the hip center was significantly higher and laterally (P < 0.001 and < 0.001, respectively) comparing primary THA.

CONCLUSION

This study demonstrated longer operative time and larger blood loss without difference in the postoperative clinical score or complications between THA after PAO and primary THA. Furthermore, THA after PAO provided larger cup size and superolaterally positioned cup center without difference in the cup inclination or anteversion comparing primary THA.

Total hip arthroplasty using a three-dimensional porous titanium acetabular cup: an examination of micromotion using subject-specific finite element analysis

Background

We investigated the mid-term clinical and radiological results of total hip arthroplasty (THA) using a three-dimensional (3D) porous titanium cup and analyzed the micromotion at the interface of the cup using subject-specific finite element (FE) analysis.

Methods

We evaluated 73 hips of 65 patients (6 men and 59 women; mean age at the time of surgery, 62.2 years; range, 45–86 years) who had undergone THA using a 3D porous titanium cup. Clinical evaluations were performed using the Japanese Orthopaedic Association (JOA) hip score system. We assessed the fixation of the acetabular component based on the presence of radiolucent lines and cup migration using anteroposterior radiographs. Subject-specific FE models were constructed from computed tomography data.

Results

The JOA score improved from a preoperative mean of 52.2 (range, 23–82) to a mean of 87.8 (range, 71–100) at the final follow-up. None of the patients underwent revisions during the follow-up period. Radiolucent lines were observed in 26 cases (35.6%) and frequently appeared at DeLee and Charnley Zone 3. Following the FE analysis, the micromotion at DeLee and Charnley Zone 3 was significantly larger than that at Zone 2. Furthermore, micromotion was large in the groups in which radiolucent lines appeared at Zone 3.

Conclusions

The mid-term clinical outcome of THA using a 3D porous titanium cup was excellent. However, radiolucent lines frequently appeared at DeLee and Charnley Zone 3. FE analysis indicated that micromotion was large at the same site, strongly suggesting that it contributes to the emergence of radiolucent lines. The 3D porous titanium cups are useful in THA, and with improvements focused on micromotion, we anticipate better long-term outcomes.

Peptide-Enriched Silk Fibroin Sponge and Trabecular Titanium Composites to Enhance Bone Ingrowth of Prosthetic Implants in an Ovine Model of Bone Gaps

Osteoarthritis frequently requires arthroplasty. Cementless implants are widely used in clinics to replace damaged cartilage or missing bone tissue. In cementless arthroplasty, the risk of aseptic loosening strictly depends on implant stability and bone–implant interface, which are fundamental to guarantee the long-term success of the implant. Ameliorating the features of prosthetic materials, including their porosity and/or geometry, and identifying osteoconductive and/or osteoinductive coatings of implant surfaces are the main strategies to enhance the bone-implant contact surface area. Herein, the development of a novel composite consisting in the association of macro-porous trabecular titanium with silk fibroin (SF) sponges enriched with anionic fibroin-derived polypeptides is described. This composite is applied to improve early bone ingrowth into the implant mesh in a sheep model of bone defects. The composite enables to nucleate carbonated hydroxyapatite and accelerates the osteoblastic differentiation of resident cells, inducing an outward bone growth, a feature that can be particularly relevant when applying these implants in the case of poor osseointegration. Moreover, the osteoconductive properties of peptide-enriched SF sponges support an inward bone deposition from the native bone towards the implants. This technology can be exploited to improve the biological functionality of various prosthetic materials in terms of early bone fixation and prevention of aseptic loosening in prosthetic surgery.

Effect of articular capsule repair on postoperative dislocation after primary total hip replacement by the anterolateral approach

Objective

Artificial hip dislocation is one of the most serious complications following total hip replacement. This study was performed to assess articular capsule repair in primary total hip replacement with the anterolateral approach (Watson-Jones incision) and its effect on postoperative dislocation.

Methods

Patients who underwent primary total hip replacement by the anterolateral approach in Tongren Hospital of Shanghai Jiao Tong University School of Medicine from June 2007 to June 2014 were retrospectively analyzed. The patients were divided into the repair and dissection groups based on the articular capsule repair status during surgery. Postoperative dislocation rates were compared between the two groups using the chi-squared test.

Results

The repair and dissection groups comprised 137 and 248 patients, respectively. All patients were followed up for 6 months to 5 years (average, 3.75 years). The mean age, sex, disease composition, and follow-up time were not significantly different between the two groups. Early postoperative dislocation occurred in 1 hip (0.7%) in the repair group and 13 hips (5.2%) in the dissection group.

Conclusions

During the anterolateral approach for primary total hip replacement, articular capsule repair may reduce the occurrence of early postoperative dislocation of the hip joint.

[Clinical application of three-dimensional printed metal prosthesis in joint surgery]

Objective

To summarize the application progress of three-dimensional (3D) printed metal prosthesis in joint surgery.

Methods

The related literature was extensively reviewed. The effectiveness of 3D printed metal prosthesis in treatment of joint surgery diseases were discussed and summarized, including the all key issues in prosthesis transplantation such as prosthesis stability, postoperative complications, bone ingrowth, etc.

Results

3D printed metal prosthesis has good matching degree, can accurately reconstruct and restore joint function, reduce operation time, and achieve high patient satisfaction in short- and medium-term follow-up. Its application in joint surgery has made good progress.

Conclusion

The personalized microporous structure prostheses of different shapes produced by 3D printing can solve the problem of poor personalized matching of joints for special patients existing in traditional prostheses. Therefore, 3D printing technology is full of hope and will bring great potential to the reform of orthopedic practice in the future.

Curative effect and prognosis of 3D printing titanium alloy trabecular cup and pad in revision of acetabular defect of hip joint

Curative effect and prognosis of 3D printing titanium alloy trabecular cup and pad in revision of acetabular defect of hip joint were investigated. Forty-two patients who underwent acetabular revision in the Second Affiliated Hospital of Luohe Medical College were divided into observation and control groups according to different methods of acetabular revision and revision materials. 3D printed titanium alloy trabecular cups and pads were used in the observation group, and non-3D printed titanium trabecular cups and pads were used in the control group. Preoperative and postoperative pain visual analog scale (VAS score), hip Harris scores and quality of life Health Survey Scale (SF-36) scores were compared between the groups. At 3, 6 and 12 months after operation, Harris score and SF-36 score of the observation group were significantly higher than those of the control group, and VAS score was significantly lower than that of the control group (P<0.05). Stability and bone ingrowth of prosthesis in the observation group were better than those in the control group. Revision of the hip prosthesis with 3D printed titanium trabecular metal cups and pads resulted in satisfactory outcomes. Short-term prognosis is satisfactory but the long-term prognosis remains to be further investigated.

Computed tomography evaluation of the periacetabular gap of a porous tantalum acetabular component

The periacetabular gap is an inherent consequence of the peripheral rim press-fit of the porous tantalum acetabular component. The circumference of the prosthesis is clearly depicted with computed tomography (CT) images that have been optimised to reduce metal artefacts. This case report highlights the utility of single-energy metal artefact reduction (SEMAR) for CT evaluation of the periacetabular gap by comparing CT images with and without SEMAR. A 70-year-old woman with a 5-year history of rheumatoid arthritis underwent total hip arthroplasty with a porous tantalum modular acetabular component. A periacetabular gap was suspected by plain radiography 2 weeks postoperatively. The metal artefacts rendered evaluation of the circumference of the acetabular component difficult in CT images acquired without SEMAR. In contrast, there were fewer metal artefacts, and a periacetabular gap (depth of 6.5 mm in DeLee and Charnley zone 2) was clearly depicted in CT images with SEMAR 2 weeks postoperatively. The porous surface of the acetabular component was in contact with the anterior and posterior rims of the acetabulum. Gap filling with bone and bone ingrowth into the porous surface were observed on CT images with SEMAR 24 weeks postoperatively. In conclusion, SEMAR reduces metal artefacts and improves CT image quality around the circumference of the acetabular component. The periacetabular gap and its filling with bone are clearly depicted in CT images with SEMAR, but not without SEMAR.

Radiolucency around highly porous sockets and hydroxyapatite-coated porous sockets in total hip arthroplasty for hip dysplasia

Studies over the past decade have reported that the use of highly porous sockets in total hip arthroplasty (THA) results in osseointegration and long-term implant stability. However, some reports have raised concerns regarding radiographic evidence of poor osseointegration with features of fibrous tissue ingrowth. The purpose of this study was to compare clinical and radiographic assessments of highly porous sockets with those of hydroxyapatite (HA)-coated porous sockets in THA for hip dysplasia (DDH) at least 1 year after surgery. A total of 127 patients (136 hips) were recruited for the study. Of these, 94 patients (101 hips) received highly porous sockets with clustered screws, while 33 patients (35 hips) received HA-coated porous sockets with clustered screws. There was no difference in clinical outcomes between the two types of sockets. All HA-coated porous sockets were radiographically stable, without radiolucent lines. Fifteen hips had radiolucent lines in two or three DeLee and Charnley zones, accompanied by sclerotic lines along the circumferences of the highly porous sockets. A significant difference in the height of the preoperative osteophyte of the anterior acetabular wall was observed between 86 hips with one or no radiolucent lines and 15 hips with two or three radiolucent lines. In cases of DDH with atrophic bone remodeling pattern, highly porous sockets with multiple screws may be used, while HA-coated porous sockets with clustered screws result in better sealing of the bone–component interface.

Tantalum coating of porous carbon scaffold supplemented with autologous bone marrow stromal stem cells for bone regeneration in vitro and in vivo

Porous tantalum metal with low elastic modulus is similar to cancellous bone. Reticulated vitreous carbon (RVC) can provide three-dimensional pore structure and serves as the ideal scaffold of tantalum coating. In this study, the biocompatibility of domestic porous tantalum was first successfully tested with bone marrow stromal stem cells (BMSCs) in vitro and for bone tissue repair in vivo. We evaluated cytotoxicity of RVC scaffold and tantalum coating using BMSCs. The morphology, adhesion, and proliferation of BMSCs were observed via laser scanning confocal microscope and scanning electron microscopy. In addition, porous tantalum rods with or without autologous BMSCs were implanted on hind legs in dogs, respectively. The osteogenic potential was observed by hard tissue slice examination. At three weeks and six weeks following implantation, new osteoblasts and new bone were observed at the tantalum-host bone interface and pores. At 12 weeks postporous tantalum with autologous BMSCs implantation, regenerated trabecular equivalent to mature bone was found in the pore of tantalum rods. Our results suggested that domestic porous tantalum had excellent biocompatibility and could promote new bone formation in vivo. Meanwhile, the osteogenesis of porous tantalum associated with autologous BMSCs was more excellent than only tantalum implantation. Future clinical studies are warranted to verify the clinical efficacy of combined implantation of this domestic porous tantalum associated with autologous BMSCs implantation and compare their efficacy with conventional autologous bone grafting carrying blood vessel in patients needing bone repairing.

Radiostereometric analysis study of tantalum compared with titanium acetabular cups and highly cross-linked compared with conventional liners in young patients undergoing total hip replacement

BACKGROUND

Radiostereometric analysis provides highly precise measurements of component micromotion relative to the bone that is otherwise undetectable by routine radiographs. This study compared, at a minimum of five years following surgery, the micromotion of tantalum and titanium acetabular cups and femoral head penetration in highly cross-linked polyethylene liners and conventional (ultra-high molecular weight polyethylene) liners in active patients who had undergone total hip replacement.

METHODS

This institutional review board-approved prospective, randomized, blinded study involved forty-six patients. Patients were randomized into one of four cohorts according to both acetabular cup and polyethylene liner. Patients received either a cementless cup with a titanium mesh surface or a tantalum trabecular surface and either a highly cross-linked polyethylene liner or an ultra-high molecular weight polyethylene liner. Radiostereometric analysis examinations and Short Form-36 Physical Component Summary, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), University of California Los Angeles (UCLA) activity, and Harris hip scores were obtained preoperatively, postoperatively, at six months, and annually thereafter.

RESULTS

All patients had significant improvement (p < 0.05) in Short Form-36 Physical Component Summary, WOMAC, UCLA activity, and Harris hip scores postoperatively. On radiostereometric analysis examination, highly cross-linked polyethylene liners showed significantly less median femoral head penetration at five years (p < 0.05). Steady-state wear rates from one year to five years were 0.04 mm per year for ultra-high molecular weight polyethylene liners and 0.004 mm per year for highly cross-linked polyethylene liners. At the five-year follow-up, the median migration (and standard error) was 0.05 ± 0.20 mm proximally for titanium cups and 0.21 ± 0.05 mm for tantalum cups.

CONCLUSIONS

In this young population who had undergone total hip replacement, radiostereometric analysis showed significantly less femoral head penetration in the highly cross-linked polyethylene liners compared with that in the conventional ultra-high molecular weight polyethylene liners. Penetration rates were one order of magnitude less in highly cross-linked polyethylene liners compared with ultra-high molecular weight polyethylene liners. There was no significant difference in proximal migration between the tantalum and titanium acetabular cups through the five-year follow-up (p > 0.19).

Three-year follow up utilizing tantal cones in revision total knee arthroplasty

There still is no consensus on the treatment of choice in revision knee arthroplasty associated with severe femoral and/or tibial bone loss. A total of 44 patients underwent revision knee arthroplasty procedures using porous tantalum cones (TM cones) to reconstruct tibial and/or femoral bone defects. At latest follow up after 37 months (32-48), 38 patients remained in the study. Tibial and femoral bone loss was categorized according to the AORI-Classification. The average preoperative KSS improved from 34 (range, 6-90) to 63 points (range, 7-90 points). The VAS improved from 7.5 to 4.8. Two patients required a re-revision due to aseptic loosening. There was no correlation between the different types of knee prosthesis implanted. Our study shows favourable clinical and radiological outcomes using TM cones in managing significant bone loss in revision total knee surgery.

Smoking may be a harbinger of early failure with ultraporous metal acetabular reconstruction

BACKGROUND

Smoking is considered a risk factor for surgical complications in total hip arthroplasty (THA) and has been linked to a higher rate of aseptic loosening in uncemented acetabular components. Acetabular reconstruction with newer ultraporous metals in both complex primary and revision THA has increased survivorship but it is unclear whether smoking affects survival of these implants.

QUESTIONS/PURPOSES

We reviewed our early experience with THA using ultraporous acetabular components to assess the incidence and etiology of early failure and examine if any preoperative variables, including smoking, related to failure.

METHODS

We used ultraporous acetabular components in 498 patients (534 hips), beginning with one case each in 1999 and 2004, 17 in 2005, and the majority from 2006 through March 2010. There were 159 complex primary and 375 revision cases. Of these patients, 17% were smokers (averaging 35 pack-years), 31% previous smokers (averaging 29 pack-years), 41% nonsmokers, and 1% unknown. Failure modes possibly related to smoking were infection, aseptic loosening, or periacetabular fracture and unrelated were dislocation and implant breakage. Minimum followup was 1 month (average, 32 months; range, 1-78 months).

RESULTS

There were 34 cup failures (6%): 17 infections, 14 aseptic loosening, and one each liner breakage, dislocation, and periacetabular fracture. The failure rate (uncontrolled for potentially confounding variables) was 10% in both current (9 of 89) and prior smokers (17 of 167) and 3% in nonsmokers 8 of 271).

CONCLUSION

With ultraporous metal technology in complex primary and revision THA, smoking, both past and current, may be a risk factor for early failure.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.