A cemented mobile-bearing total knee prosthesis prevents peri-prosthetic bone mineral density loss around the femoral component: a consecutive follow-up at a mean of 11 years

Variations in bone mineral density after joint replacement: A systematic review examining different anatomical regions, fixation techniques and implant design

Purpose

This study aims to evaluate postoperative periprosthetic bone mineral density (BMD) at various time points following joint replacement with different implant designs and fixation techniques.

Methods

Database search was conducted on MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Web of Science, and CINAHL for studies analyzing bone remodelling after joint replacement (March 2002-January 2024). Inclusion criteria: English-language articles; total joint replacement; at least two BMD evaluations; observational studies, cross-sectional, prospective, retrospective, randomised controlled trials, and clinical trials. Exclusion criteria: no BMD measurement within one month after surgery; BMD data only expressed as percentage changes or graphs without numerical values; no Gruen zone evaluation for hip replacement; no periprosthetic bone evaluation for knee replacement; pharmacological treatment or comorbidities affecting BMD; revision joint replacements; irrelevant articles; no full text or no original data.

Results

Sixty-eight articles matched the selection criteria. Fifty-five focused on the hip joint, 12 on the knee, and one on the shoulder. After total hip arthroplasty, the greatest bone resorption occurred in the proximal femur, peaking at 6 months. Cemented implants and tapered stems showed greater bone resorption than cementless implants and anatomical stems. BMD around the acetabular component decreased during the first 6 months but increased in regions subjected to higher loads. In total knee arthroplasty, bone loss occurred in the anterior distal femur and medial tibial plateau, with cemented and posterior-stabilised implants showing greater bone loss than cementless and cruciate-retaining designs.

Conclusions

The periprosthetic BMD decreases progressively after joint replacement. The fixation technique and implant design influence the extent and pattern of this decline. These factors must be considered during the surgical planning, as they can have long-term implications for bone health and implant longevity. Further research is needed to optimise implant design and surgical techniques to mitigate BMD loss and improve patient outcomes.

Level of Evidence

Level IV.

Clinical use of quantitative computed tomography to evaluate the effect of less paraspinal muscle damage on bone mineral density changes after lumbar interbody fusion

STUDY DESIGN

A retrospective cohort study.

PURPOSE

This study aimed to assess the reliability of quantitative computed tomography (QCT) in measuring bone mineral density (BMD) of instrumented vertebrae and investigate the effect of less paraspinal muscle damage on BMD changes after lumbar interbody fusion.

OVERVIEW OF LITERATURE

Patients always experience a decrease in vertebral BMD after lumbar interbody fusion. However, to the best of our knowledge, no study has analyzed the effect of paraspinal muscles on BMD changes.

METHODS

This retrospective analysis included a total of 155 patients who underwent single-level lumbar fusion, with 81 patients in the traditional group and 74 patients in the Wiltse group (less paraspinal muscle damage). QCT was used to measure the volumetric BMD (vBMD), Hounsfield unit value, and cross-sectional area of the paraspinal muscles at the upper instrumented vertebrae (UIV), vertebrae one segment above the UIV (UIV+1), and the vertebrae one segment above the UIV+1 (UIV+2). Statistical analyses were performed.

RESULTS

No significant differences in general data were observed between the two groups (p>0.05). Strong correlations were noted between the preoperative and 1-week postoperative vBMD of each segment (p<0.01), with no significant difference between the two time points in both groups (p>0.05). Vertebral BMD loss was significantly higher in UIV+1 and UIV+2 in the traditional group than in the Wiltse group (-13.6%±19.1% vs. -4.2%±16.5%, -10.8%±20.3% vs. -0.9%±37.0%; p<0.05). However, no statistically significant difference was observed in the percent vBMD changes in the UIV segment between the two groups (37.7%±70.1% vs. 36.1%±78.7%, p>0.05).

CONCLUSIONS

QCT can reliably determine BMD in the instrumented spine after lumbar interbody fusion. With QCT, we found that reducing paraspinal muscle destruction through the Wiltse approach during surgery can help preserve the adjacent vertebral BMD; however, it does not help increase the BMD in the instrumented vertebrae.

Factors influencing periprosthetic bone mineral density in total knee arthroplasty: a systematic review

INTRODUCTION

Following total knee arthroplasty (TKA), there is a significant decline in periprosthetic bone mineral density (BMD), potentially resulting in complications such as prosthetic loosening, periprosthetic fracture, and influencing the postoperative recovery. The objective of this study was to summarize the factors influencing periprosthetic BMD in TKA from existing studies.

METHODS

A comprehensive systematic search was performed in 4 databases: Pubmed, Embase, Web of Science, and Cochrane Library. The last search was carried out on October 12, 2023. We used the keywords ''total knee arthroplasty'', ''bone mineral density'' and each of them combined with ''tibia'' and ''femur'' to identify all relevant articles reporting about potential impact factors influencing the periprosthetic BMD in patients after TKA.

RESULTS

Out of 1391 articles, 22 published from 2001 to 2023 were included in this systematic review. Following eligibility screening, six significant categories affecting periprosthetic BMD were recognized: prosthesis type, design of stem, coating, body weight, cement, and peg distance.

CONCLUSION

Mobile-bearing prostheses, modular polyethylene design, short stems, cruciform stems, avoidance of bone cement, higher body mass index, titanium nitride coating, and a smaller medial peg distance could potentially benefit periprosthetic BMD. Comprehensive consideration of diverse factors influencing periprosthetic BMD before surgery and collaboration with post-operative drug therapy are essential.

TRIAL REGISTRY

The PROSPERO registration number is CRD42023472030.