Changes in bone mineral density of both proximal femurs after total knee arthroplasty

Changes in Muscle Mass and Bone Density and Their Relationship After Total Knee Arthroplasty

Purpose: To investigate the effects of total knee arthroplasty (TKA) on muscle mass and bone density in end-stage knee osteoarthritis (OA). Methods: This prospective study was conducted on 111 patients with Kellgren-Lawrence grade 4 knee OA who underwent TKA after failing to respond to conservative treatment for more than 3 months at a single institution from June 2022 to May 2023. Appendicular lean mass index (ALMI) and bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry before and every 6 months after surgery. The average follow-up period was 15.5 ± 2.31 months (range, 11.6-24 months). Results: During the follow-up period after TKA, the ALMI increased relatively continuously and consistently. The BMD of the L-spine and proximal femur did not change significantly until 12 months after TKA surgery but began to increase steeply after 12 months and slowed down after 18 months. The increase in muscle mass showed a significant positive correlation with the increase in BMD. Conclusions: Muscle mass gradually increased after TKA for end-stage knee OA, whereas bone density also increased but not until 12 months after surgery. The significant positive correlation between the increase in muscle mass and bone density suggests that the increase in muscle mass after TKA may be one of the causes of the increase in bone density.

Subtrochanteric fracture of the femur following knee replacement surgery: A case series and review of the literature

INTRODUCTION AND IMPORTANCE

Knee arthroplasties as an effective intervention is primarily performed in patients with primary osteoarthritis and rheumatoid arthritis. Risk of hip fracture may be either decreased or increased in patients with Knee arthroplasties. There is conflicting evidence in this regard. Over the years, some studies have reported the occurrence of hip fractures following this operation as a rare but severe complication. The aim of the present case series was to report diagnosis and treatment of the mentioned five cases.

CASE PRESENTATION

During a period of two years, five patients with a diagnosis of a subtrochanteric fracture and history of total knee arthroplasty who referred to hospital were selected to include in the present case series. CLINICAL DISCUSSION: the presence of RA and treatment with glucocorticoids, a reduction of BMD following knee replacement surgery, and ultimately, an increase in physical activity and movement after the arthroplasty due to the improvement of preoperational pain, may all contribute in a complex manner to the observed outcome of increased fracture risk in the hip following TKA.

CONCLUSION

In summary, special care including using medications to improve BMD should be taken to minimize the risk of such an event.

Stress Fracture of the Femoral Neck Following Total Knee Arthroplasty: A Case Series

A stress fracture of the femoral neck after total knee arthroplasty (TKA) is rare, with few reported cases in the English literature. We defined a stress fracture following TKA as a nontraumatic fracture developing in the femoral neck within six months of TKA. This retrospective case series highlights the predisposing factors, diagnostic challenges, and management of stress femoral neck fractures following TKA. In our series, the major risk factors for the fracture are an increase in the level of activity in osteoporotic bone after a period of relative immobility after TKA, steroid intake, and rheumatoid arthritis. Preoperative dual-energy X-ray absorptiometry (DEXA) screening may help in the early initiation of osteoporosis treatment as the majority of our cases come late in the knee arthritis stage and long after a period of relative inactivity. Timely diagnosis and management of a stress femur neck fracture in the early period may prevent fracture displacement, avascular necrosis, and nonunion.

[Progress of change in bone mineral density after knee arthroplasty]

Objective

To summarize research progress of change in bone mineral density (BMD) after knee arthroplasty and its diagnostic methods, influencing factors, and drug prevention and treatment.

Methods

The relevant literature at home and abroad was reviewed and summarized from research status of the advantages and disadvantages of BMD assessment methods, the trend of changes in BMD after knee arthroplasty and its influencing factors, and the differences in effectiveness of drugs.

Results

The central BMD and mean BMD around the prosthesis decrease after knee arthroplasty, which is closely associated with body position, age, weight, daily activities, and the fixation methods, design, and material of prosthesis. Denosumab, bisphosphonates, and teriparatide et al. can decrease BMD loss after knee arthroplasty.

Conclusion

BMD after knee arthroplasty decreases, which is related to various factors, but the mechanism is unclear. At present, some inhibitors of bone resorption can decrease BMD loss after knee arthroplasty. However, its long-term efficacy remains to be further explored.

Bone Mineral Density Around the Knee Joint: Correlation With Central Bone Mineral Density and Associated Factors

INTRODUCTION

The aims of this study were to (1) assess the bone mineral density (BMD) around the knee joint, (2) determine the correlation between central and knee BMDs, and (3) investigate the factors associated with BMD around the knee joint in patients with knee osteoarthritis (OA).

METHODOLOGY

This cross-sectional study included 122 patients who underwent total knee arthroplasty. Central and knee dual-energy X-ray absorptiometry was performed preoperatively. BMD at 6 regions of interest (ROIs) around the knee joint were measured, and their correlations with central BMD were determined using Spearman's correlation analysis. Lower limb alignment, severity of OA, body mass index (BMI), preoperative functional and pain scores were assessed to elucidate the factors associated with knee BMD using linear regression analysis.

RESULTS

Around the knee joint, BMD was the lowest at the distal femoral metaphysis and lateral tibial condyle. Knee BMD was significantly correlated with central BMD. However, the correlation coefficients varied by the ROI. Additionally, multivariate analysis revealed different associations with respect to the regions around the knee joint. Varus alignment of the lower limb was associated with increased BMD of the medial condyles and decreased BMD of lateral condyles. High grade OA was a protective factor; it was associated with increased BMD at the lateral condyles of the femur and tibia. Higher BMI was an independent protective factor in all ROIs around the knee joint except the lateral femoral condyles. Lower functional level was not associated with decreased BMD, whereas a higher pain score was significantly associated with lower BMD at the proximal tibial metaphysis.

CONCLUSIONS

Knee BMD was significantly correlated with central BMD. However, the correlations varied with the regions around the knee joint probably due to their independent association with the alignment of the lower limb, severity of OA, BMI, and preoperative pain level.

Bone mineralization changes of the glenoid in shoulders with symptomatic rotator cuff tear

PURPOSE

Computed tomography osteoabsorptiometry (CTO) is a method to analyze the stress distribution in joints by measuring the subchondral bone density. The purpose of this study was to evaluate the bone mineralization changes of the glenoid in shoulders with rotator cuff tears by CTO and to evaluate whether rotator cuff tears are associated with stress changes in the glenoid.

METHODS

In total, 32 patients, who were diagnosed with unilateral rotator cuff tears and underwent arthroscopic rotator cuff repair, were enrolled in this study. They underwent CT scanning of both shoulders pre-operatively and the glenoid was evaluated using CTO. Hounsfield units (HU) in seven areas of the glenoid were compared between the affected and unaffected sides.

RESULTS

The central area of the glenoid on the affected side had significantly lower HU than on the unaffected side among all patients. Focusing on the rotator cuff tear size and the subscapularis tendon, only patients with larger cuff tears or with subscapularis tendon tears showed significantly lower HU in the central area of the affected side.

CONCLUSIONS

This study showed a decrease in bone mineralization density in the central glenoid in shoulders with rotator cuff tear. This change was observed in the case of larger cuff tears and subscapularis tendon tears. Our results help clarify the changes in stress distribution in the shoulder joint caused by symptomatic rotator cuff tears.

A Review on Bone Mineral Density Loss in Total Knee Replacements Leading to Increased Fracture Risk

The link between low bone mineral density (BMD) scores leading to greater fracture risk is well established in the literature; what is not fully understood is the impact of total knee replacements/revisions or arthroplasties on BMD levels. This literature review attempts to answer this question. Several different databases using specific key terms were searched, with additional papers retrieved via bibliographic review. Based on the available evidence, total knee replacements/revisions and arthroplasties lower BMD and thus increase fracture risk. This review also addresses the possible implications of this research and possible options to reduce this risk.

Posterior Cruciate Ligament Retention or Substitution During Total Knee Arthroplasty Does Not Affect Long-Term Bone Mineral Density or Quality

BACKGROUND

Physical activity is recognized as one of the factors that influence bone mineral density (BMD) and bone quality after total knee arthroplasty (TKA). According to biomechanical analyses after posterior cruciate ligament (PCL) retaining (PCLR) and substituting (PCLS) TKA, each implant design has different kinematics and kinetics. The purposes of this study were: (1) to perform within-patient comparisons of the midterm and long-term effects of PCL retention in mobile-bearing TKA on proximal femur and tibia BMD and calcaneus bone quality measured using ultrasound and (2) to identify correlations between them.

METHODS

A prospective, quasi-randomized design was used. Thirty-seven patients (74 knees) who underwent bilateral TKA (PCLR on one side and PCLS on the other) were evaluated. Mean follow-up periods were 118 months (standard deviation 40) and 117 months (standard deviation 36) in knees with PCLR and PCLS implants, respectively. The BMDs of the total hip and proximal tibia and broadband ultrasound attenuation (BUA; dB/MHz) through the calcaneus were measured.

RESULTS

The mean BMD of PCLR and PCLS were equivalent at the proximal hip and tibia. The BUA of the calcaneus was also the same between implants. There were significant correlations between the 3 anatomic sites.

CONCLUSION

When measured approximately 10 years after TKA, PCL retention had no substantial effect on the BMD of the proximal femur and tibia, or on the bone quality of the calcaneus. The measurement of noninvasive BUA may predict BMD, although further analysis is required.

Bone mineral decreases in the calcanei in men after arthroscopic shoulder surgery: a prospective study over 5 years

PURPOSE

It is well known that injuries and surgical procedures in the lower extremities affect bone mineral both in the injured limb and in the contralateral limb. The possible effect on bone mineral after upper extremity surgery is not well studied, and the aim of this study was to study the effect on bone mineral in the calcanei after arthroscopic shoulder surgery.

METHODS

Twenty-two men scheduled for arthroscopic shoulder surgery underwent bone mineral area (BMA) mass measurements in both calcanei using the Calscan DXL device prior to surgery and after 6, 18, 36 and 60 months. On every occasion, the Tegner activity score and EuroQoL 5-dimensions (EQ-5D) were assessed.

RESULTS

During 5 years, there was a significant decrease in the BMA in both calcanei (p = 0.003). The Tegner activity score decreased from preinjury to the operation and did not increase significantly after the operation. The EQ-5D increased significantly after the operation.

CONCLUSION

The bone mineral in the calcanei in men during the 5-year study period decreased more than the expected age-dependent decline after arthroscopic shoulder surgery. There was an increase in health-related quality of life as measured with the EQ-5D after arthroscopic Bankart reconstruction.

LEVEL OF EVIDENCE

Case-control study, Level III.

A study investigating short- and medium-term effects on function, bone mineral density and lean tissue mass post-total knee replacement in a Caucasian female post-menopausal population: implications for hip fracture risk

Significant increased hip fracture incidence has been reported in the year following total knee replacement. This study demonstrates that bone and muscle loss is a post-surgical consequence of total knee replacement, alongside poor outcomes in function and activity potentially contributing to reduced quality of life and increased hip fracture risk.

INTRODUCTION

A significant increase in hip fracture incidence in the year following total knee replacement (TKR) surgery has been reported. This study investigated function and activity following TKR and the effects of limited mobility on bone and muscle loss and their potential contribution to hip fracture risk.

METHODS

Changes in dual-energy X-ray absorptiometry (DXA) (GE Lunar Prodigy, Bedford MA), bone mineral density (BMD) at the neck of femur (NOF), total hip region (TH) and lumbar spine were measured alongside leg lean tissue mass (LLTM) in post-menopausal Caucasian females following TKR (N = 19) compared to controls (N = 43). Lumbar spine trabecular bone scores (TBSs) were calculated. Ipsilateral/contralateral weight bearing, lower limb function, 3-day pedometer readings, pain levels and falls were also recorded. Measurements were obtained at pre-surgery baseline and at 6 weeks, 6 months and 12 months post-surgery.

RESULTS

No statistically significant differences were demonstrated between groups at baseline bilaterally in LLTM or BMD at the NOF and TH. Losses in ipsilateral NOF and TH BMD and contralateral LLTM were significantly higher in the TKR group at 6 months. Impairment in function and weight bearing persisted in the TKR group 12 months post-operatively alongside deficits in bilateral muscle mass and ipsilateral NOF and TH BMD. Falls incidence was not significantly higher in the TKR group.

CONCLUSIONS

Bone loss at the hip with associated muscle loss is a consequence of TKR that, in addition to poor patient outcomes in function and activity, potentially contributes to increased hip fracture risk in the year following surgery.

Bone Mineral Density Changes in the Hip and Spine of Men and Women 1-Year After Primary Cemented Total Knee Arthroplasty: Prospective Cohort Study

This study evaluated age- and sex-adjusted changes in total hip and spine bone mineral density (BMD) within 1 year of total knee arthroplasty (TKA) using a prospective, longitudinal cohort with a one-year follow-up. Preoperatively, subjects underwent routine bone mineral densitometry of their hip and spine, which was repeated 12 months postoperatively. Of 108 subjects, 97 (90%) completed BMD testing. Total hip BMD decreased significantly over time (1.80% change, P<0.001) with females losing more than males (P<0.001). The pattern was similar, but attenuated in the spine. Subjects undergoing primary cemented TKA had significant bone loss in the hip within 12 months, beyond that expected with age.

Bone quality of the calcaneus 5years after total knee arthroplasty

We used non-invasive broadband ultrasound attenuation (BUA) to determine whether the pre-surgical bone quality of the calcaneus was improved 5years postoperatively, and whether the interval between total knee arthroplasty (TKA) surgeries influenced post-surgical calcaneal bone quality. All patients underwent scheduled, staged, bilateral TKA. Twenty-one patients (42 TKAs) with bilateral knee osteoarthritis were evaluated. One day before and 5years after TKA, BUA through the os calcis on the surgical side was measured. Fourteen out of 21 patients showed post-surgical improvement in BUA bilaterally. When all 42 cases were considered together there was a significant improvement in BUA 5years after surgery (P=0.042). There were no significant correlations between the changes in BUA on each side and the interval between TKA surgeries.