Seven to twelve year results with Versys ET cementless stem. A retrospective study of 225 cases

Carbon Nanotubes and Graphene as Nanoreinforcements in Metallic Biomaterials: a Review

Current challenges in existing metallic biomaterials encourage undertaking research in the development of novel materials for biomedical applications. This paper critically reviews the potential of carbon nanotubes (CNT) and graphene as nanoreinforcements in metallic biomaterials for bone tissue engineering. Unique and remarkable mechanical, electrical, and biological properties of these carbon nanomaterials allow their use as secondary-phase reinforcements in monolithic biomaterials. The nanoscale dimensions and extraordinarily large surface areas of CNT and graphene make them suitable materials for purposeful reaction with living organisms. However, the cytocompatibility of CNT and graphene is still a controversial issue that impedes advances in utilizing these promising materials in clinical orthopedic applications. The interaction of CNT and graphene with biological systems including proteins, nucleic acids, and human cells is critically reviewed to assess their cytocompatibity in vitro and in vivo. It is revealed that composites reinforced with CNT and graphene show enhanced adhesion of osteoblast cells, which subsequently promotes bone tissue formation in vivo. This potential is expected to pave the way for developing ground-breaking technologies in regenerative medicine and bone tissue engineering. In addition, current progress and future research directions are highlighted for the development of CNT and graphene reinforced implants for bone tissue engineering.

Influence of femoral broach shape on stem alignment using anterior approach for total hip arthroplasty: A radiologic comparative study of 3 different stems

Background

Malalignment of the femoral stem in total hip arthroplasty (THA) can detrimentally affect outcome. Poor preparation of the femur intraoperatively is an important cause of stem malalignment.

Purposes

The objective was to compare coronal alignment of three different stems using three different broaches.

Methods

Retrospective study of three groups of 60 patients following primary THA via direct anterior approach, by the same surgeon, between January 2015 and January 2016. Each group had a similar designed stem (Corail Depuy, Targos Lepine or Meije Tornier). Groups were matched for age, body mass index, gender, side, neck shaft angle and indications. The significant difference between groups was the broach shape. Broaches for the Corail and Meije stems had a prominent shoulder laterally, while the broach of the Targos stem had a rounded less prominent shape laterally. Coronal alignment was determined radiologically at 2 months.

Results

The mean varus was significantly lower for the Targos stems (1.1° +/-0.8) compared to the Corail (2.3° +/-1.5) and Meije stems (1.9° +/-1.2) (p<0.0001). There were significantly less Targos stems with varus greater than 3° (1.7%, n = 1) compared to the Corail (40%, n = 24) and Meije stems (20%, n = 12) (p<0.001).

Conclusion

A femoral broach with a prominent lateral shoulder when performing a THA via direct anterior approach will increase the risk of varus femoral stem alignment compared to a less laterally prominent broach.

Intrawound Vancomycin Powder in Primary Total Hip Arthroplasty Increases Rate of Sterile Wound Complications

Purpose

Total hip arthroplasty (THA) is a successful surgery for the treatment of hip osteoarthritis; however, the risk of a post-operative prosthetic joint infection (PJI) remains at 1% to 2%. The purpose of this study was to investigate the safety profile of using vancomycin powder (VP) to reduce infection rates by reviewing acute postoperative complications.

Materials and Methods

A retrospective review of 265 consecutive patients undergoing THA was performed. The first 128 patients, the control group, did not receive VP, and the subsequent 137 patients, the VP group, received VP at the time of wound closure. Patient demographic data, medical comorbidities, and perioperative information were compared.

Results

The primary outcome was a post-operative surgical complication within 90 days from surgery. The control and VP group's demographic, medical comorbidities and perioperative information data were statistically similar. Deep infection rate in the control group was 5.5%, whereas the deep infection rate in the VP group was 0.7% (P=0.031). Sterile wound complication rate was 4.4% in the VP group, and 0% in the control group (P=0.030). Remaining complications were not statistically different between the groups.

Conclusion

VP was associated with an increase rate of sterile wound complications compared to the control group. The rate of PJI was decreased with the use of VP. We do not recommend for or against the use of VP at time of wound closure to prevent PJI, and higher powered studies will need to be performed to demonstrate the efficacy of VP.

Aseptic loosening rate of the Mayo femoral stem with medium-term follow up

The aseptic loosening rate of the Mayo hip prosthesis femoral stem was determined in a 44 patient (52 hips) series, by comparing preoperative and postoperative clinical and radiographic parameters, over a minimal 5-year postoperative period. Loosening was obvious before five years in four hips (7.6%), while the stem was considered stable in the remaining 48 hips over a mean 6.1 year period, therefore accounting for a 92.3% Kaplan-Meier survival rate. We conclude that the aseptic loosening rate is too high for the Mayo hip prosthesis femoral stem, as compared to literature data concerning the non-conservative stems.

[Cement-free and cemented Excia hip shaft prosthesis: comparison of intermediate term results]

AIM OF THE STUDY

For fixation of total hip prostheses, cemented and cement-free techniques are available. Normally, anchoring techniques and the definitive endoprosthesis model are determined preoperatively based on the available information, such as the quality of bone. Some newer endoprosthesis models utilize the same instruments for both implantation techniques. In this way it is possible to decide on the final anchoring technique intraoperatively. Because such a combined endoprosthesis system has been used in our clinic for 10 years, we were interested in the clinical results at the intermediate stage.

MATERIAL AND METHODS

In a prospective, non-randomized study 105 pairs from a continuing series were formed from 105 cases treated with cement-free prostheses and the latest cemented shaft implants from the same year. In this way a total of 210 hip shaft endoprostheses from the years 2002 to 2006 were included in the study. After an average time period of 6.3 years (range 4.5-8.2 years) the patients were recalled for a follow-up examination. The clinical results, early and late complications were analyzed. The immediately postoperative X-ray images and those from the follow-up examination were evaluated by an independent external expert with respect to primary positioning, migration and any signs of loosening.

RESULTS

At the follow-up examination at an average of 6.3 years the quota was 73%. The indications for cement-free/cemented total hip endoprosthesis were: primary arthritis 87%/98%, secondary arthritis 10%/2% and others 3%/0%. At the time of the last follow-up examination 4 and 14 patients, respectively, had died. The visual analog scale (VAS) for pain was given as 0.72/0.78. The Harris hip score improved from 54/48 to 93/90 points. The implant-related survival rate was 99.5%. Due to a periprosthetic fracture one of the cemented shafts had to be removed. Luxation occurred in 3/2 cases, respectively, of which 4 could be conservatively treated. In one cement-free case a head elongation and a change to an inlay with an anti-luxation shoulder was necessary. A fracture of the trochanter major was conservatively treated and an intraoperative shaft fissure was stabilized with wire cerclage and titan banding. The radiological evaluation showed no implant loosening or statistically significant differences in the shaft positioning.

DISCUSSION

Short and intermediate clinical and radiological results showed no differences in patients of similar average age in the sixth decade of life. The significant improvements in the Harris hip score and the range of movement could be confirmed in the intermediate term and are comparable to other current implants. It can be concluded that an intraoperative decision on the fixation technique based on the macroscopically visible bone quality supports the reliably good results of both methods.

Hip resurfacing versus total hip arthroplasty: a systematic review comparing standardized outcomes

BACKGROUND

Metal-on-metal hip resurfacing was developed for younger, active patients as an alternative to THA, but it remains controversial. Study heterogeneity, inconsistent outcome definitions, and unstandardized outcome measures challenge our ability to compare arthroplasty outcomes studies.

QUESTIONS/PURPOSES

We asked how early revisions or reoperations (within 5 years of surgery) and overall revisions, adverse events, and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA among patients with hip osteoarthritis. Secondarily, we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries.

METHODS

We conducted a systematic review of English language studies published after 1996. Adverse events of interest included rates of early failure, time to revision, revision, reoperation, dislocation, infection/sepsis, femoral neck fracture, mortality, and postoperative component alignment. Revision rates were compared with those from four national joint replacement registries. Results were reported as adverse event rates per 1000 person-years stratified by device market status (in use and discontinued). Comparisons between event rates of metal-on-metal hip resurfacing and THA are made using a quasilikelihood generalized linear model. We identified 7421 abstracts, screened and reviewed 384 full-text articles, and included 236. The most common study designs were prospective cohort studies (46.6%; n = 110) and retrospective studies (36%; n = 85). Few randomized controlled trials were included (7.2%; n = 17).

RESULTS

The average time to revision was 3.0 years for metal-on-metal hip resurfacing (95% CI, 2.95-3.1) versus 7.8 for THA (95% CI, 7.2-8.3). For all devices, revisions and reoperations were more frequent with metal-on-metal hip resurfacing than THA based on point estimates and CIs: 10.7 (95% CI, 10.1-11.3) versus 7.1 (95% CI, 6.7-7.6; p = 0.068), and 7.9 (95% CI, 5.4-11.3) versus 1.8 (95% CI, 1.3-2.2; p = 0.084) per 1000 person-years, respectively. This difference was consistent with three of four national joint replacement registries, but overall national joint replacement registries revision rates were lower than those reported in the literature. Dislocations were more frequent with THA than metal-on-metal hip resurfacing: 4.4 (95% CI, 4.2-4.6) versus 0.9 (95% CI, 0.6-1.2; p = 0.008) per 1000 person-years, respectively. Adverse event rates change when discontinued devices were included.

CONCLUSIONS

Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing, except when discontinued devices are removed from the analyses. Results from the literature may be misleading without consistent definitions, standardized outcome metrics, and accounting for device market status. This is important when clinicians are assessing and communicating patient risk and when selecting which device is most appropriate for individual patients.

Periprosthetic fractures around a cementless hydroxyapatite-coated implant: a new fracture pattern is described

BACKGROUND

Periprosthetic fractures can occur both intraoperatively and postoperatively with implantation of cementless tapered stems.

QUESTIONS/PURPOSES

In a large cohort of patients receiving cementless, proximally hydroxyapatite-coated femoral implants, we answered the following questions: What was the incidence of intraoperative and postoperative fractures associated with the implant? What were the fracture patterns as classified by the Vancouver classification system? Did the Vancouver classification represent the fracture patterns found? How were the fractures treated and what were the treatment outcomes; that is, how many fractures healed and did the stems osseointegrate?

METHODS

We evaluated 1039 hips (932 patients) from three prospective studies. The hips were divided into three groups: no fractures, intraoperative fractures, and postoperative fractures. Demographic differences among the groups were noted. Postoperative fractures were classified using the Vancouver classification system. We judged stem stability using Engh's criteria and fracture union was determined by the treating surgeon and confirmed by the authors.

RESULTS

We identified 58 periprosthetic fractures in the 1039 hips (5.6%): 38 intraoperative (3.7%) and 20 postoperative (1.9%). Eleven of the postoperative fractures were classifiable by the original Vancouver classification system and nine were of the newly described "clamshell" variety, not classifiable by this system. No intraoperative fractures extended below the lesser trochanter. Twenty-five of these fractures were treated with a single cable or cerclage wire. The remaining received no specific treatment. Of the 20 postoperative fractures, five were treated nonoperatively. All stems osseointegrated.

CONCLUSIONS

Both intraoperative and postoperative fractures can be managed with success when the stem is stabilized or found to be osseointegrated. An adjustment to the Vancouver classification is suggested to include the clamshell fracture, which has not been previously described.