Periprosthetic bone remodeling using a triple-taper polished cemented stem in total hip arthroplasty

Stem alignment with short tapered-wedge cementless stems affects bone mineral density continuously for at least 5 years after primary total hip arthroplasty

AIM

This study aimed to assess the relationship between the three-dimensional (3D) alignment of short tapered-wedge cementless stems and bone mineral density (BMD) changes in patients followed up for 5 years after total hip arthroplasty (THA).

METHODS

We retrospectively analysed the hips of 52 patients who underwent THA using short tapered-wedge cementless stems at our institution from 2013 to 2016 with complete 5-year follow-up data. We evaluated the relationship between stem alignment, measured using a 3D-templating software, and BMD changes in the 7 Gruen zones.

RESULTS

After 1 year, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD in zones 3 and 4 were noted. After 5 years, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD zones 2, 3, and 4 were observed. With increased amounts of varus/flexion stem alignment, the amount of BMD loss decreased. There was no correlation between anteverted stem insertion and changes in BMD levels.

CONCLUSIONS

Our data showed that stem alignment affects BMD based on 5-year follow-up data after surgery. Careful observation is necessary, especially when using short tapered-wedge cementless stems, as stem alignment may affect changes in BMD levels more than 5 years after surgery.

The insidious risk of periprosthetic fracture in clinically functional total hip arthroplasties: A biomechanical study of willed joints

Femoral bone quality is a major risk factor of periprosthetic fracture after total hip arthroplasty (THA), which has mortality similar to native hip fractures but higher short-term morbidity. The goal of this study was to quantify cortical strains at the site of expected Vancouver Type-B periprosthetic fracture as a function of bone mineral density, femoral stem material, and fixation method using a series of 29 autopsy-retrieved, clinically asymptomatic hip joints with THA. Periprosthetic bone mineral content and density was assessed using dual-energy X-ray absorptiometry by Gruen Zone. Specimens then underwent combined cyclic axial and torsional loading, increasing incrementally from 100 N and ±1 Nm to peaks of 700 N and ±5 Nm. All specimens experienced significantly higher strains on the lateral surface than on the anterior surface, indicating that the bending loads in the frontal plane, rather than axial/torsional loads, had the predominant effect. Multiple significant relationships (p = 0.04, p = 0.02) were found between predicted periprosthetic strains calculated from radiographic measurements and observed principal strains. Though THA in the present study were in successful clinical service, the produced results indicated that some femurs with rigid cemented or noncemented implants were potentially at high risk for Vancouver Type-B fractures, which may be predicted radiographically.

Minimum ten-year outcome of a triple-tapered femoral stem implanted with line-to-line cementing technique

Background

A triple-tapered polished femoral stem was implanted with line-to-line cementing technique. The purpose of this study was to determine the survivorship, loosening rate, stem subsidence, radiologic changes and clinical outcomes in the minimum 10-year follow-up.

Methods

This was a retrospective study done in three institutes. Finally, 118 hips in 97 patients could be followed-up at the mean follow-up period of 126.3 months. The survivorship, radiological and clinical outcomes were investigated.

Results

Radiologically, 107 hips (90.7%) were categorized to Barrack cementing grade A, and 108 stems (91.5%) were inserted in neutral position. All hips were not loose and were not revised due to any reason. Survival with revision for any reason as the endpoint was 100% after 10 years. At the last follow-up, the mean subsidence was 0.43 mm, and the subsidence was less than 1 mm in 110 hips (93.2%).

JOA hip score improved from 42.7 ± 8.9 points preoperatively to 92.8 ± 6.8 points at the last follow-up. No patient complained thigh pain.

Conclusions

Line-to-line cementing technique with use of a triple-tapered polished stem was effective to achieve good cementation quality and centralization of the stem. The subsidence was small, and the minimum 10-year results were excellent without any failures related to the stem.

Trial registration

Retrospectively registered.

Mid-term gender-specific differences in periprosthetic bone remodelling after implantation of a curved bone-preserving hip stem

BACKGROUND

The implant-specific periprosthetic bone remodelling in the proximal femur is considered to be an important factor influencing the long-term survival of cementless hip stems. Particularly data of gender-specific differences regarding bone-preserving stems are very rare in literature and mainly limited to short-term investigations. Therefore, we investigated at mid-term one arm of a prospective randomised study to evaluate if there is an influence of gender on implant-specific stress shielding after implantation of a curved bone preserving hip stem (Fitmore) 5 years postoperatively.

HYPOTHESIS

We hypothesised there will be no gender-specific differences in periprosthetic bone remodelling.

PATIENTS AND METHODS

A total of 20 female and 37 male patients underwent total hip arthroplasty using the Fitmore stem. Clinical, radiological as well as osteodensitometric examinations were performed preoperatively, 7 days and 3, 12 and 60 months postoperatively. Clinical data collection included the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Harris Hip Score (HHS). Periprosthetic bone mineral density (BMD) was measured using Dual Energy X-ray Absorptiometry (DXA) and the periprosthetic bone was divided into 7 regions of interest (ROI) for analysis. The results at 3, 12 and 60 months were compared with the first postoperative measurement after 7 days to obtain a percentage change.

RESULTS

Periprosthetic BMD showed a decrease in all 7 ROIs for both groups 5 years postoperatively referred to the baseline value, except ROI 3 (0.8%, p=0.761), representing the distal lateral part of the stem, and ROI 5 (0.3%, p=0.688), representing the distal medial part of the stem in the male cohort. Significant gender differences were found in ROI 1 (-16.0% vs. -3.5%, p=0.016) and ROI 6 (-9.9% vs. -2.1%, p=0.04) in favour of the male patients. Clinical results showed no significant gender differences 5 years postoperatively with regard to WOMAC (mean 0.4 (±0.8, 0-3.3) in women vs. 0.3 (±0.8, 0-4.2) in men, p=0.76) and HHS (mean 93.0 (±9.7, 66.0-100.0) in women vs. 93.9 (±11.5, 53.0-100.0) in men, p=0.36).

CONCLUSION

Proximal stress shielding was observed independent of gender 5 years postoperatively. However, there was a significantly lower bone loss proximal lateral and medial below the calcar in male patients, indicating a more physiological load transfer. [ClinicalTrials.gov identifier: NCT03147131 (Study ID D.3067-244/10). Registered 10 May 2017 - retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03147131?term=Bieger&draw=2&rank=1] LEVEL OF EVIDENCE: IV; prospective study without control group.

Strain shielding for cemented hip implants

BACKGROUND

Long-term survival of hip implants is of increasing relevance due to the rising life expectancy. The biomechanical effect of strain shielding as a result of implant insertion may lead to bone resorption, thus increasing risk for implant loosening and periprosthetic fractures. Patient-specific quantification of strain shielding could assist orthopedic surgeons in choosing the biomechanically most appropriate prosthesis.

METHODS

Validated quantitative CT-based finite element models of five femurs in intact and implanted states were considered to propose a systematic algorithm for strain shielding quantification. Three different strain measures were investigated and the most appropriate measure for strain shielding quantification is recommended. It is used to demonstrate a practical femur-specific implant selection among three common designs.

FINDINGS

Strain shielding measures demonstrated similar trends in all Gruen zones except zone 1, where the volumetric strain measure differed from von-Mises and maximum principal strains. The volumetric strain measure is in better agreement with clinical bone resorption records. It is also consistent with the biological mechanism of bone remodeling so it is recommended for strain shielding quantification. Applying the strain shielding algorithm on three different implants for a specific femur suggests that the collared design is preferable. Such quantitative biomechanical input is valuable for practical patient specific implant selection.

INTERPRETATION

Volumetric strain should be considered for strain shielding examination. The presented methodology may potentially enable patient-specific pre-operative strain shielding evaluation so to minimize strain shielding. It should be further used in a longitudinal study so to correlate between strain shielding predictions and clinical bone resorption.

Radiographic evaluation of cementation technique using polished, conical, triple-tapered femoral stem in hip arthroplasty

Objective

To radiographically evaluate the quality of cementation and implantation technique using a polished, triple-tapered femoral stem in total hip arthroplasty (THA).

Method

Retrospective study with radiographic evaluation of 86 hips in 83 patients who underwent to primary THA with the triple-tapered cemented femoral stem C-Stem (DePuy Orthopedics, Warsaw, Indiana). Cases with at least one-year of follow-up were included, and data related to preoperative, immediate postoperative, and late postoperative radiographic evolution were recorded. This study analyzed, among others, the proximal femoral anatomy, the quality of cementation as described by Barrack, and the implant positioning. Cementation was also evaluated and quantified in the Gruen zones with one-year of follow-up.

Results

The mean age was 62.85 years. Proximal femoral anatomical conformation was Dorr type A in 34 (39.53%) cases, type B in 52 (60.46%), and no type C cases were found. Five (5.81%) cases were defined as type A by Barrack's cementation classification system, 46 (56.49%) type B, 27 (31.40%) type C, and eight (9.30%) type D. The greatest cement mantle thickness was observed in zones four (15.53 mm) and 11 (15.64 mm), and the smallest in zone nine (3.51 mm). Positioning in varus was observed in eight (9.3%) cases, valgus in 25 (29%), forward deviation in two (5%), and backward deviation in 55 (63.95%).

Conclusions

The C-Stem femoral system presented satisfactory results related to cementation pattern, positioning, osteolysis, and stress shielding with regard to literature referring to double-tapered or triple-tapered models, demonstrating to be a safe method, with a predictable and reliable cementing pattern.

Periprosthetic femoral bone loss in total hip arthroplasty: systematic analysis of the effect of stem design

INTRODUCTION

Periprosthetic bone loss may lead to major complications in total hip arthroplasty (THA), including loosening, migration, and even fracture. This study analysed the influence of femoral implant designs on periprosthetic bone mineral density (BMD) after THA.

METHODS

The results of all previous published studies reporting periprosthetic femoral BMD following THA were compiled. Using these results, we compared percent changes in bone loss as a function of: femoral stem fixation, material, and geometry.

RESULTS

The greatest bone loss was in the calcar region (Gruen Zone 7). Overall, cemented stems had more bone loss distally than noncemented stems, while noncemented stems had more proximal bone loss than cemented stems. Within noncemented stems, cobalt-chromium (CoCr) stems had nearly double the proximal bone loss compared to titanium (Ti) alloy stems. Finally, within noncemented titanium alloy group, straight stems had less bone loss than anatomical, tapered, and press-fit designs.

DISCUSSION

The findings from the present study quantified percent changes in periprosthetic BMD as a function of fixation method, alloy, and stem design. While no one stem type was identified as ideal, we now have a clearer understanding of the influence of stem design on load transfer to the surrounding bone.

Periprosthetic Bone Remodeling After Novel Short-Stem Neck-Sparing Total Hip Arthroplasty

BACKGROUND

Short femoral stems have been designed with the aims of reducing proximal bone loss, improving load transfer, and increasing compressive loads at the medial proximal femoral calcar. This study examines bone mineral density (BMD) changes associated with a novel neck sparing short femoral stem design.

METHODS

The study was a prospective, single-center, multi-investigator consecutive series, which assessed bone-remodeling changes after insertion of the MSA Stem (Global Orthopaedic Technology). Dual-energy X-ray absorptiometry scans were performed preoperatively and postoperatively at 6, 12, and 24 months assessing the BMD at the 7 Gruen zones. The secondary objectives assessed were the Harris Hip Score, 12-Item Short Form Health Survey preoperatively, and perioperative complications.

RESULTS

Thirty-nine total hip arthroplasties were performed on 37 patients, with 27 patients completing the 24-month dual-energy X-ray absorptiometry scan. The overall preoperative baseline BMD was 0.2. At 6 months, the Gruen zone BMD had increased significantly in all zones in comparison to the preoperative mean BMD. Between 6 months and 24 months, there were only slight changes in the Gruen zones, with small gains in zones 1-2 and zones 4-6, with no zone showing a significant decrease. The Harris Hip Score improved from a preoperative mean of 39.7-75.3, whereas the 12-Item Short Form Health Survey score also improved from 32.6 to 49 at 24 months. However, 5 patients had aseptic loosening requiring revision surgery (4 femoral and 1 acetabular component).

CONCLUSION

Short-stem neck-sparing femoral stem prosthesis has the capacity to address the stress-shielding problem identified in femoral stems. However, the high early revision rate is a significant issue.

A Cannulated Tri-Tapered Femoral Stem for Total Hip Arthroplasty: Clinical and Radiological Results at Ten Years

We report the ten-year clinical and radiological outcomes of a novel cannulated, tri-tapered femoral stem, used in primary total hip arthroplasty (110 stems in 98 patients). At ten years, two Tri-taper stems had been revised for infection and dislocation. The mean Oxford Hip Score improved from 13.46 pre-operatively, to 37.04. Radiological analysis revealed radiolucent lines in 57 cases, but none exceeded 2 mm thickness. Stem subsidence was identified in 63 cases, with mean distal tip migration of 3.8 mm. Survivorship with revision for aseptic loosening as the end point was 100% at 10 years. Stem survival with revision for any cause was 98.2% (95% CI, 92.9% to 99.5%). The ten-year results of the Tri-taper stem are comparable to other polished, tapered femoral stems.

Triple taper stem design shows promising fixation and bone remodelling characteristics: radiostereometric analysis in a randomised controlled trial

Cemented femoral stems with force closed fixation designs have shown good clinical results despite high early subsidence. A new triple-tapered stem in this category (C-stem AMT) was introduced in 2005. This study compares this new stem with an established stem of similar design (Exeter) in terms of migration (as measured using radiostereometric analysis), peri-prosthetic bone remodelling (measured using dual energy x-ray densitometry, DXA), Oxford Hip Score, and plain radiographs. A total of 70 patients (70 hips) with a mean age of 66 years (53 to 78) were followed for two years. Owing to missing data of miscellaneous reasons, the final analysis represents data from 51 (RSA) and 65 (DXA) patients. Both stems showed a typical pattern of migration: Subsidence and retroversion that primarily occurred during the first three months. C-stem AMT subsided less during the first three months (p = 0.01), before stabilising at a subsidence rate similar to the Exeter stem from years one to two. The rate of migration into retroversion was slightly higher for C-stem AMT during the second year (p = 0.03). Whilst there were slight differences in movement patterns between the stems, the C-stem AMT exhibits good early clinical outcomes and displays a pattern of migration and bone remodelling that predicts good clinical performance.

Salmon calcitonin (Miacalcic ns 200 IU) in prevention of bone loss after hip replacement

BACKGROUND AND AIMS

Loosening of a hip prosthesis after total arthroplasty is related to periprosthetic bone loss. Calcitonin has been used in the treatment of bone loss in osteoporosis and prevention of fractures. The main purposes of the study were firstly to evaluate the effect of calcitonin on periprosthetic bone after total hip arthroplasty, secondly investigate possible loosening of the prosthesis and thirdly examine further clinical outcome.

PATIENTS AND METHODS

60 patients who underwent total hip arthroplasty using cemented Exeter prosthesis were randomized in the treatment group (salmon calcitonin 200 IU nasal spray daily + calcium 500 mg) and the placebo group (inactive nasal spray + calcium 500 mg) for six months. Bone mineral density (BMD) was measured from different locations at the time of discharge and after six and 12 months. Dynamic histomorphometry on bone biopsies taken from femoral collum was performed. Serum bone-specific alkaline phosphatase (BAP), serum osteocalcine (OC) and cross-linked N-telopeptides (NTX) were measured after one week, one month, three months and 12 months. Clinical manifestations and the incidence of fractures and loosening of the prosthesis were followed up to eight years.

RESULTS

Statistically there was not significant difference in bone histomorphometry between the groups. In both groups there was a significant BMD decrease in periprosthetic bone. However, the difference between the groups was not statistically significant. In the biochemical analysis NTX increased more in the Miacalcic group than in the placebo group (p = 0.013). There were no significant differences between the groups in serum BAP or OC even though the changes within the groups were statistically significant. No loosening of the prosthesis was seen during the follow-up and there was no need for revision of any reason. Four fractures were recorded in three patients. One patient sustained a periprosthetic fracture. All the patients with fractures were allocated in the placebo group.

CONCLUSIONS

Nasal salmon calcitonin 200 IU on a daily basis does not promote any additional value on calcium substitution to prevent bone loss after hip replacement. The durability of the Exeter prosthesis was good.

A 5-8 year retrospective follow-up of the C-stem AMT femoral component: patient reported outcomes and survivorship analysis

We report midterm functional, radiographic and survivorship data for the cemented, triple taper C-stem AMT femoral component from a consecutive cohort of 415 hip arthroplasties in 386 patients at a non-developer centre. Follow-up ranges were from 60 to 99 months, with a mean of 76 months. 32 hips were lost to follow-up. The median OHS was 40, median SF-12 mental component score (MCS) was 50, and median SF-12 physical component score (PCS) was 39. At 99 months follow up, stem survivorship is 96.9% (95% confidence interval (CI) 82.5-99.5), and construct survivorship is 96.0% (95% CI 84.2-99.0). Adverse events such as calcar fracture, greater trochanter fracture and dislocation were rare at <1%. There have been no revisions for aseptic loosening.

WITHDRAWN: Periprosthetic Bone Mineral Density After Total Hip Arthroplasty With an AMIStem or Quadra Femoral Component Performed by a Minimally Invasive Anterior Approach (AMIS): A Prospective Randomized Clinical Dual-Energy X-ray Absorptiometry Study

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The C-stem in clinical practice: fifteen-year follow-up of a triple tapered polished cemented stem

The triple tapered polished cemented stem, C-Stem, introduced in 1993 was based on the original Charnley concept of the "flat back" polished stem. We present our continuing experience with the C-Stem in 621 consecutive primary arthroplasties implanted into 575 patients between 1993 and 1997. Four hundred and eighteen arthroplasties had a clinical and radiological follow-up past 10 years with a mean follow-up of 13 years (10-15). There were no revisions for stem loosening but 2 stems were revised for fracture - both with a defective cement mantle proximally. The stem design and the surgical technique support the original Charnley concept of limited stem subsidence within the cement mantle and the encouraging results continue to stand as a credit to Sir John Charnley's original philosophy.

Effect of sliding-taper compared with composite-beam cemented femoral prosthesis loading regime on proximal femoral bone remodeling: a randomized clinical trial

BACKGROUND

This two-year randomized clinical trial was performed to examine whether the geometry of the cemented femoral prosthesis affects the pattern of strain-adaptive bone remodeling in the proximal aspect of the femur after primary total hip arthroplasty.

METHODS

One hundred and twenty patients were randomized to receive a Charnley (composite-beam), Exeter (double-tapered), or C-Stem (triple-tapered) prosthesis. The change in proximal femoral bone mineral density over two years was measured by dual x-ray absorptiometry (DXA). Bone turnover markers were measured in urine and serum samples collected at the preoperative baseline and during the first postoperative year. N-telopeptide of type-I collagen was measured in urine as a marker of osteoclast activity, and osteocalcin was measured in serum as a marker of osteoblast activity. Clinical outcome was measured with use of the Harris and Oxford hip scores and prosthesis migration was measured with use of digitized radiographs during the first two postoperative years.

RESULTS

The baseline characteristics of the subjects in each group were similar (p > 0.05). Decreases in femoral bone mineral density were observed over the first year for all prosthesis designs, with no further loss during the second year. The decreases were similar in regional distribution and magnitude between the composite-beam and sliding-taper designs (p > 0.05). Bone loss was greatest (14%) in the proximal medial aspect of the femur (Gruen zone 7). Transient increases in both N-telopeptide of type-I collagen and osteocalcin activity also occurred over the first year, and these increases were similar in pattern among the three prosthesis groups (p > 0.05). All prostheses showed migration patterns that were consistent with their design type, and similar improvements in clinical hip scores were observed over the two-year course of the study.

CONCLUSIONS

Differences in the mechanism of load transfer between the prosthesis and host bone in composite-beam or sliding-taper cemented femoral prosthesis designs were not a major determinant of proximal femoral bone loss after total hip arthroplasty, and the design that included a third taper exhibited a remodeling profile that was similar to those of the double-tapered design.