Local bone quality affects the outcome of prosthetic total knee arthroplasty

Survival of primary total knee arthroplasty in a modern anatomic implant with and without a short stem extension

INTRODUCTION

In primary conventional TKA, the tibial fixation is achieved by the epiphyseal and metaphyseal zone. One of those two zones of fixation, can be compromised by the local bone quality (bone micro-architecture and resistance), previous surgery or decreased surface of contact, leading to micro-mobility of the implant and potentially leading to aseptic loosening (AL). It was our hypothesis that the addition of a short fully cemented stem would improve the metaphyseal and epiphyseal fixation of the implant. To verify this hypothesis, the goals of this retrospective study were therefore to compare if (1) The presence of a short, stubby stem will dissipate stress and decrease micro-mobility at the epiphyseal level resulting in less radiolucent lines around the tibial component. (2) Short stem primary TKA may improve survivorship of the implant in patients potentially at risk for aseptic loosening.

MATERIALS AND METHODS

Retrospective cohort study of 326 patients operated with a morphometric implant between 2013 and 2018. A short stubby stem was added to the tibial implant, if at the time of the tibial cut, the surgeon judged the epiphyseal bone quality to be poor or a smaller tibial size was necessary. All primary TKA were radiographically evaluated. RLLs were recorded and described according to their radiological aspect, localization, time of appearance and their progression over time. Survivorship was compared in the 2 groups using the national joint registry.

RESULTS

71 TKAs out of 326 (22%) were stemmed. Of the 255 TKAs without stem, 53 (21%) showed RLLs under the tibial base plate and 1 case (0.4%) was revised for potential AL of the tibial implant. No RLLs were observed in the group of stemmed implants and no revisions for aseptic loosening were needed. Patients with stubby stems were elderly women with risk factors for osteoporosis or young men in need for correction of big coronal deformities.

CONCLUSION

A short stubby stem extension can reduce the rate of RLLs and AL in primary TKA, probably by adding metaphyseal fixation to the classic epiphyseal fixation of the tibia and by a reduction in micro- and macro-motion of the tibial component. Based on the results of our study, the addition of a short cemented stubby stem decreased the rate of RLL with no revision observed in the stemmed group during the study period. The used knee system allows this option. Intra-operative decision can be made easily when risk factors such as osteoporosis, female gender, big deformities, obesity can be identified.

LEVEL OF EVIDENCE

III.

Is surgeon assessed bone quality during total knee arthroplasty a valid tool to diagnose osteoporosis?

Osteoporosis continues to have a high prevalence amongst people undergoing total knee arthroplasty (TKA). The surgeon assessed intraoperative bone quality using a visual analogue scale has a strong correlation with bone mineral density. Surgeon assessment of bone quality has a high specificity(100%) and positive predictive value(100%) in diagnosing osteoporosis and osteopenia.

BACKGROUND

Patients undergoing TKA have a high prevalence of osteoporosis. Our aim is to study (a) the correlation of intraoperative surgeon assessed bone quality with bone mineral density(BMD) as measured by dual-energy x-ray absorptiometry(DEXA) and (b) the diagnostic strength of intraoperative surgeon assessment of bone quality in diagnosing osteoporosis and osteopenia, in patients undergoing TKA.

METHODS

We prospectively recruited 31 patients undergoing TKA. Patients were classified into normal, osteopenia or osteoporosis based on preoperative DEXA. Intraoperatively, the senior surgeon by visual and tactile assessment, graded the bone quality(BQ) using a visual analogue scale(VAS) from 0 to 10, with 10 being the strongest bone. Using the VAS score, we classified patients as normal(≥ 8), osteopenia(5-7) and osteoporosis(≤ 4).

RESULTS

The Spearman's rho correlation between BMD and VAS was 0.954.(p < 0.001). VAS < 8 to diagnose osteopenia and osteoporosis had a sensitivity of 70.83%, specificity of 100%, positive predictive value of 100% and diagnostic accuracy of 77.42%(p = 0.001). VAS ≤ 4 to diagnose osteoporosis had a sensitivity of 71.43%, specificity of 100%, positive predictive value of 100% and diagnostic accuracy of 93.55%(p < 0.001).

CONCLUSION

The surgeon assessed intraoperative bone quality using a VAS during TKA has a strong correlation with the gold standard BMD as measured by DEXA scan. VAS ≤ 4 can help diagnose osteoporosis, allowing surgeons to augment implant fixation with stem and cement as well as guide osteoporosis treatment postoperatively. VAS < 8 can identify osteopenic or osteoporotic bone, thus allowing the surgeon to better identify weaker bone and help titrate implant choice.

Incidence of Total Knee Arthroplasty in Older Females with Knee Osteoarthritis and Osteoporosis Treated with Denosumab Compared with Those Treated Using Bisphosphonates: A Population-Based Cohort Study

This study aimed to evaluate the incidence of total knee arthroplasty (TKA), a marker of severe knee osteoarthritis (OA), among older females with concurrent knee OA and osteoporosis (OP) who were treated with denosumab or bisphosphonates. By analyzing a large population-based cohort, we sought to clarify how these treatments influence the progression of knee OA to the point of requiring surgical intervention. We used data from the Taiwan National Health Insurance Research Database, including data from females aged ≥ 50 years diagnosed with knee OA and OP who initiated treatment between 2012 and 2019. Propensity score matching (1:1) resulted in the selection of 13,774 patients (6897 per group). The TKA incidence was analyzed using Cox proportional hazards models. Patients treated with denosumab had a lower TKA incidence than those treated with bisphosphonates (6.9 vs. 8.5 per 1000 person-years). The adjusted hazard ratio (aHR) for TKA in the denosumab group was 0.77 (95% CI: 0.62-0.97; p = 0.024), with the most pronounced effect observed in patients aged ≥ 80 years (aHR = 0.39, 95% CI: 0.20-0.77; p = 0.007). These findings suggest that denosumab reduces TKA risk more effectively than bisphosphonates and may serve as a superior treatment option for mitigating severe knee OA progression, especially in older adults.

Osteoporosis in the setting of knee arthroplasty: a narrative review

Patients undergoing knee replacement, which is mainly indicated in severe osteoarthritis, are frequently co-affected by osteoporosis and osteopenia. With a prevalence standing at around 20% in patients receiving knee arthroplasty, osteoporosis could lead to poor outcomes postoperatively. Some of these complications include periprosthetic fractures and an increased revision rate. Antiresorptive medications have been shown to be beneficial postoperatively. However, no studies have been conducted on whether they had any benefits if given preoperatively. Surgical management may also be beneficial, but this area remains full of controversy.

Cementless Total Knee Arthroplasty: Is it Safe in Demineralized Bone?

There is concern for cementless total knee arthroplasty (TKA) in patients with decreased bone mineral density (BMD) due to the potential increase in complications, namely failed in-growth or future aseptic loosening. Some data suggest that advances in cementless prostheses mitigate these risks; however this is not yet born out in long-term registry data. It is crucial to expand our understanding of the prevalence and etiology of osteoporosis in TKA patients, survivorship of cementless implants in decreased BMD, role of bone-modifying agents, indications and technical considerations for cementless TKA in patients with decreased BMD. The purpose of this study is to review current literature and expert opinion on such topics.

Team Approach: Bone Health Optimization in Orthopaedic Surgery

» Bone health optimization (BHO) has become an increasingly important consideration in orthopaedic surgery because deterioration of bone tissue and low bone density are associated with poor outcomes after orthopaedic surgeries.» Management of patients with compromised bone health requires numerous healthcare professionals including orthopaedic surgeons, primary care physicians, nutritionists, and metabolic bone specialists in endocrinology, rheumatology, or obstetrics and gynecology. Therefore, achieving optimal bone health before orthopaedic surgery necessitates a collaborative and synchronized effort among healthcare professionals.» Patients with poor bone health are often asymptomatic and may present to the orthopaedic surgeon for reasons other than poor bone health. Therefore, it is imperative to recognize risk factors such as old age, female sex, and low body mass index, which predispose to decreased bone density.» Workup of suspected poor bone health entails bone density evaluation. For patients without dual-energy x-ray absorptiometry (DXA) scan results within the past 2 years, perform DXA scan in all women aged 65 years and older, all men aged 70 years and older, and women younger than 65 years or men younger than 70 years with concurrent risk factors for poor bone health. All women and men presenting with a fracture secondary to low-energy trauma should receive DXA scan and bone health workup; for fractures secondary to high-energy trauma, perform DXA scan and further workup in women aged 65 years and older and men aged 70 years and older.» Failure to recognize and treat poor bone health can result in poor surgical outcomes including implant failure, periprosthetic infection, and nonunion after fracture fixation. However, collaborative healthcare teams can create personalized care plans involving nutritional supplements, antiresorptive or anabolic treatment, and weight-bearing exercise programs, resulting in BHO before surgery. Ultimately, this coordinated approach can enhance the success rate of surgical interventions, minimize complications, and improve patients' overall quality of life.

MRI-based vertebral bone quality score: relationship with age and reproducibility

Vertebral bone quality (VBQ) score is an opportunistic measure of bone mineral density using routine preoperative MRI in spine surgery. VBQ score positively correlates with age and is reproducible across serial scans. However, extrinsic factors, including MRI machine and protocol, affect the VBQ score and must be standardized.

PURPOSE

The purposes of this study were to determine whether VBQ score increased with age and whether VBQ remained consistent across serial MRI studies obtained within 3 months.

METHODS

This retrospective study evaluated 136 patients, age 20-69, who received two T1-weighted lumbar MRI within 3 months of each other between January 2011 and December 2021. VBQ(L1-4) score was calculated as the quotient of L1-L4 signal intensity (SI) and L3 cerebral spinal fluid (CSF) SI. VBQ(L1) score was calculated as the quotient of L1 SI and L1 CSF SI. Regression analysis was performed to determine correlation of VBQ(L1-4) score with age. Coefficient of variation (CV) was used to determine reproducibility between VBQ(L1-4) scores from serial MRI scans.

RESULTS

One hundred thirty-six patients (mean ± SD age 44.9 ± 12.5 years; 53.7% female) were included in this study. Extrinsic factors affecting the VBQ score included patient age, MRI relaxation time, and specific MRI machine. When controlling for MRI relaxation/echo time, the VBQ(L1-4) score was positively correlated with age and had excellent reproducibility in serial MRI with CV of 0.169. There was excellent agreement (ICC > 0.9) of VBQ scores derived from the two formulas, VBQ(L1) and VBQ(L1-4).

CONCLUSION

Extrinsic factors, including MRI technical factors and age, can impact the VBQ(L1-4) score and must be considered when using this tool to estimate bone mineral density (BMD). VBQ(L1-4) score was positively correlated with age. Reproducibility of the VBQ(L1-4) score across serial MRI is excellent especially when controlling for technical factors, supporting use of the VBQ score in estimating BMD. The VBQ(L1) score was a reliable alternative to the VBQ(L1-4) score.

A call to "own the bone": osteoporosis is a predictor for adverse two-year outcomes following total hip and knee arthroplasty

PURPOSE

While bone health is instrumental in orthopedic surgery, few studies have described the long-term outcomes of osteoporosis (OP) in patients undergoing total hip (THA) or knee (TKA) arthroplasties.

METHODS

Using the New York State statewide planning and research cooperative system database, all patients who underwent primary TKA or THA for osteoarthritis from 2009 to 2011 with minimum 2-year follow-up were identified. They were divided based on their OP status (OP and non-OP) and 1:1 propensity score matched for age, sex, race, and Charlson/Deyo index. Cohorts were compared for demographics, hospital-related parameters, and 2-year postoperative complications and reoperations. Multivariate binary logistic regression was utilized to identify significant independent associations with 2-year medical and surgical complications and revisions.

RESULTS

A total of 11,288 TKA and 8248 THA patients were identified. OP and non-OP TKA patients incurred comparable overall hospital charges for their surgical visit and hospital length of stay (LOS) (both, p ≥ 0.125). Though OP and non-OP THA patients incurred similar mean hospital charges for their surgical visit, they experienced longer hospital LOS (4.3 vs. 4.1 days, p = 0.035). For both TKA and THA, OP patients had higher rates of overall and individual medical and surgical complications (all, p < 0.05). OP was independently associated with the 2-year occurrence of any overall, surgical, and medical complications, and any revision in TKA and THA patients (all, OR ≥ 1.42, p < 0.001).

CONCLUSION

Our study found OP was associated with a greater risk of 2-year adverse outcomes following TKA or THA, including medical, surgical, and overall complications as well as revision operations compared to non-OP patients.

The impact of prior fragility fractures on long-term periprosthetic fracture risk following total knee arthroplasty

The study found that patients undergoing total knee arthroplasty with prior fragility fracture had increased risk of subsequent fragility fracture and periprosthetic fracture within 8 years postoperatively when compared to those without a prior history. However, these patients were not at increased risk for all-cause revision within this period.

PURPOSE

The aim of this study was to characterize the association of prior FFs on long-term risk of secondary fragility fracture (FF), periprosthetic fracture (PPF), and revision TKA.

METHODS

Patients at least 50 years of age who underwent elective TKA were identified in the PearlDiver Database. Patients were stratified based on whether they sustained a FF within 3 years prior to TKA (7410 patients) or not (712,954 patients). Demographics and comorbidities were collected. Kaplan Meier analysis was used to observe the cumulative incidence of all-cause revision, PPF, and secondary FF within 8 years of TKA. Cox Proportional hazard ratio analysis was used to statistically compare the risk.

RESULTS

In total, 1.0% of patients had a FF within three years of TKA. Of these patients, only 22.6% and 10.9% had a coded diagnosis of osteoporosis and osteopenia, respectively, at time of TKA. The 8-year cumulative incidence of secondary FF and periprosthetic fracture was significantly higher in those with a prior FF (27.5% secondary FF and 1.9% PPF) when compared to those without (9.1% secondary FF and 0.7% PPF). After adjusting for covariates, patients with a recent FF had significantly higher risks of secondary FF (HR 2.73; p < 0.001) and periprosthetic fracture (HR 1.86; p < 0.001) than those without a recent FF.

CONCLUSIONS

Recent FF before TKA is associated with increased risk for additional FF and PPF within 8 years following TKA. Surgeons should ensure appropriate management of fragility fracture is undertaken prior to TKA to minimize fracture risk, and if not, be vigilant to identify patients with prior FF or other bone health risk factors who may have undocumented osteoporosis.

Near-infrared spectroscopy for structural bone assessment

Disorders of bone integrity carry a high global disease burden, frequently requiring intervention, but there is a paucity of methods capable of noninvasive real-time assessment. Here we show that miniaturized handheld near-infrared spectroscopy (NIRS) scans, operated via a smartphone, can assess structural human bone properties in under three seconds. A hand-held NIR spectrometer was used to scan bone samples from 20 patients and predict: bone volume fraction (BV/TV); and trabecular (Tb) and cortical (Ct) thickness (Th), porosity (Po), and spacing (Sp). NIRS scans on both the inner (trabecular) surface or outer (cortical) surface accurately identified variations in bone collagen, water, mineral, and fat content, which then accurately predicted bone volume fraction (BV/TV, inner R2 = 0.91, outer R2 = 0.83), thickness (Tb.Th, inner R2 = 0.9, outer R2 = 0.79), and cortical thickness (Ct.Th, inner and outer both R2 = 0.90). NIRS scans also had 100% classification accuracy in grading the quartile of bone thickness and quality. We believe this is a fundamental step forward in creating an instrument capable of intraoperative real-time use.

Outcome and risk factors of failures associated with revision total hip arthroplasty for recurrent dislocation

INTRODUCTION

Recurrent dislocation represents the third most common cause of revision surgery after total hip arthroplasty (THA). However, there is a paucity of information on the outcome of revision total hip arthroplasty for recurrent dislocation. In this study, we investigated (1) clinical outcomes of patients that underwent revision THA for recurrent dislocation, and (2) potential risk factors associated with treatment failure in patients who underwent revision total hip arthroplasty for recurrent dislocation.

METHODS

We retrospectively reviewed 211 consecutive cases of revision total hip arthroplasty for recurrent dislocation, 81 implanted with a constrained liner and 130 with a non-constrained liner with a large-diameter femoral head (> 32 mm). Patient- and implant-related risk factors were analyzed in multivariate regression analysis.

RESULTS

At 4.6-year follow-up, 32 of 211 patients (15.1%) underwent re-revision surgery. The most common causes for re-revision included infection (14 patients) and dislocation (10 patients). Kaplan-Meier analysis demonstrates a 5-year survival probability of 77% for patients that underwent revision THA for recurrent dislocation. Osteoporosis, obesity (BMI ≥ 40), spine disease and abductor deficiency are independent risk factors for failure of revision surgery for recurrent dislocation. Liner type (constrained vs. non-constrained) was found not to be associated with failure of revision THA for recurrent dislocation (p = 0.44).

CONCLUSION

This study suggests that THA revision for recurrent dislocation is associated with a high re-revision rate of 15% at mid-term follow-up. Osteoporosis, obesity (BMI ≥ 40) spine disease and abductor deficiency were demonstrated to be independent risk factors for failure of revision THA for recurrent dislocation.

LEVEL OF EVIDENCE

Level III, case-control retrospective analysis.

Predicting robotic-assisted total knee arthroplasty operating time

Aims

No predictive model has been published to forecast operating time for total knee arthroplasty (TKA). The aims of this study were to design and validate a predictive model to estimate operating time for robotic-assisted TKA based on demographic data, and evaluate the added predictive power of CT scan-based predictors and their impact on the accuracy of the predictive model.

Methods

A retrospective study was conducted on 1,061 TKAs performed from January 2016 to December 2019 with an image-based robotic-assisted system. Demographic data included age, sex, height, and weight. The femoral and tibial mechanical axis and the osteophyte volume were calculated from CT scans. These inputs were used to develop a predictive model aimed to predict operating time based on demographic data only, and demographic and 3D patient anatomy data.

Results

The key factors for predicting operating time were the surgeon and patient weight, followed by 12 anatomical parameters derived from CT scans. The predictive model based only on demographic data showed that 90% of predictions were within 15 minutes of actual operating time, with 73% within ten minutes. The predictive model including demographic data and CT scans showed that 94% of predictions were within 15 minutes of actual operating time and 88% within ten minutes.

Conclusion

The primary factors for predicting robotic-assisted TKA operating time were surgeon, patient weight, and osteophyte volume. This study demonstrates that incorporating 3D patient-specific data can improve operating time predictions models, which may lead to improved operating room planning and efficiency.

Cite this article: Bone Jt Open 2022;3(5):383–389.

Opportunistic Use of Lumbar Magnetic Resonance Imaging for Osteoporosis Screening

Magnetic resonance imaging (MRI) is a routine assessment before spine surgery. We found that the opportunistic use of MRI with the vertebral bone quality (VBQ) score has good diagnostic ability, with a threshold value of VBQ > 3.0, in recognizing patients who may need further osteoporosis evaluation.

INTRODUCTION

The purpose of this study was to determine whether the opportunistic use of magnetic resonance imaging (MRI) is useful for identifying spine surgical patients who need further osteoporosis evaluation.

METHODS

This retrospective study evaluated 83 thoracolumbar spine surgery patients age ≥ 50 who received T1-weighted MRI. Opportunistic MRI was evaluated with the vertebral bone quality (VBQ) score, VBQ (fat) score, and signal-to-noise ratio (SNR). Each uses the median L1-L4 vertebral body signal intensities (SI) divided by either the L3 cerebrospinal fluid (CSF) SI, average SI of the L1 and S1 dorsal fat, or standard deviation (SD) of the background SI dorsal to the skin. Single-level VBQ was calculated as the ratio of the L1 vertebral body and L1 CSF SIs. Receiver-operator curve analysis was performed to determine diagnostic ability.

RESULTS

The mean age was 70.10, 80% were female, and 96% were Caucasian. The mean ± SD VBQ, single-level VBQ, VBQ (fat), and SNR were 3.39 ± 0.68, 3.56 ± 0.81, 3.95 ± 1.89, and 113.18 ± 77.26, respectively. Using area under the curve, the diagnostic ability of VBQ, single-level VBQ, VBQ (fat), and SNR for clinical osteoporosis were 0.806, 0.779, 0.608, and 0.586, respectively. Diagnostic threshold values identified with optimal sensitivity and specificity were VBQ of 2.95 and single-level VBQ of 3.06.

CONCLUSION

Opportunistic use of MRI is a simple, effective tool that may help recognize patients who are at risk for complications related to bone disease. A VBQ > 3.0 can identify patients who need additional diagnostic evaluation.

Impact of Donor Age on the Osteogenic Supportive Capacity of Mesenchymal Stromal Cell-Derived Extracellular Matrix

Mesenchymal stromal cells (MSC) have been proposed as an emerging cell-based therapeutic option for regenerative medicine applications as these cells can promote tissue and organ repair. In particular, MSC have been applied for the treatment of bone fractures. However, the healing capacity of these fractures is often compromised by patient's age. Therefore, considering the use of autologous MSC, we evaluated the impact of donor age on the osteogenic potential of bone marrow (BM)-derived MSC. MSC from older patients (60 and 80 years old) demonstrated impaired proliferative and osteogenic capacities compared to MSC isolated from younger patients (30 and 45 years old), suggesting that aging potentially changes the quantity and quality of MSC. Moreover, in this study, we investigated the capacity of the microenvironment [i.e., extracellular matrix (ECM)] to rescue the impaired proliferative and osteogenic potential of aged MSC. In this context, we aimed to understand if BM MSC features could be modulated by exposure to an ECM derived from cells obtained from young or old donors. When aged MSC were cultured on decellularized ECM derived from young MSC, their in vitro proliferative and osteogenic capacities were enhanced, which did not happen when cultured on old ECM. Our results suggest that the microenvironment, specifically the ECM, plays a crucial role in the quality (assessed in terms of osteogenic differentiation capacity) and quantity of MSC. Specifically, the aging of ECM is determinant of osteogenic differentiation of MSC. In fact, old MSC maintained on a young ECM produced higher amounts of extracellularly deposited calcium (9.10 ± 0.22 vs. 4.69 ± 1.41 μg.μl-1.10-7 cells for young ECM and old ECM, respectively) and up-regulated the expression of osteogenic gene markers such as Runx2 and OPN. Cell rejuvenation by exposure to a functional ECM might be a valuable clinical strategy to overcome the age-related decline in the osteogenic potential of MSC by recapitulating a younger microenvironment, attenuating the effects of aging on the stem cell niche. Overall, this study provides new insights on the osteogenic potential of MSC during aging and opens new possibilities for developing clinical strategies for elderly patients with limited bone formation capacity who currently lack effective treatments.

The use of bone turnover markers for monitoring the treatment of osteoporosis in postmenopausal females undergoing total knee arthroplasty: a prospective randomized study

BACKGROUND

Osteoporosis (OP) and osteoarthritis (OA) commonly coexist in postmenopausal females. The decrease in bone density and increase in bone resorption in postmenopausal females with OP may consequently affect the surgical outcome of total knee arthroplasty (TKA). However, clinicians often ignore monitoring the treatment of OP in the perioperative management of TKA. Bone turnover marker (BTM) can timely and accurately reflect bone metabolism to monitor the treatment of OP. The purpose of this study was to investigate the effect of BTM monitoring to guide the treatment of OP in postmenopausal females undergoing TKA.

METHODS

Postmenopausal females with OP who underwent primary unilateral TKA were randomly divided into two groups (monitoring group and control group), given oral medication (alendronate, calcitriol, and calcium), and followed for 1 year. In the monitoring group, serum BTMs (C-telopeptide of type I collagen (CTX-I), N-terminal propeptide of type I procollagen (PINP), and 25(OH)D) were assessed preoperatively and repeated postoperatively; alendronate was withdrawn when CTX-I and PINP reached the reference interval; and calcitriol and calcium were withdrawn when 25(OH)D reached the reference interval. In the control group, oral medication was implemented for a uniform duration of 3 months. During the 1-year follow-up, the mean maximum total point motion (MTPM) of the tibial component, bone mineral density (BMD), visual analog scale (VAS) score, range of motion, and Oxford Knee Score (OKS) score were obtained.

RESULTS

In the monitoring group, BTM monitoring prolonged the medication duration, but did not cause more adverse reactions than in the control group. The mean MTPM values at 6 m and 12 m in the monitoring group were lower than those in the control group, and the BMD at 12 m in the monitoring group was significantly higher than that in the control group. Patients in the monitoring group had lower VAS scores at 6 m and higher OKS scores at 6 m and 12 m than those in the control group.

CONCLUSION

In postmenopausal females with osteoporosis undergoing primary TKA, the application of BTM monitoring to guide the treatment of osteoporosis can enhance bone density, maintain prosthesis stability, and improve surgical outcome.

TRIAL REGISTRATION

ChiCTR ChiCTR-INR-17010495 . Registered on 22 January 2017.

Biomechanics of Implant Fixation in Osteoporotic Bone

PURPOSE OF REVIEW

The purpose of this review is to critically evaluate the current literature regarding implant fixation in osteoporotic bone.

RECENT FINDINGS

Clinical studies have not only demonstrated the growing prevalence of osteoporosis in patients undergoing total joint replacement (TJR) but may also indicate a significant gap in screening and treatment of this comorbidity. Osteoporosis negatively impacts bone in multiple ways beyond the mere loss of bone mass, including compromising skeletal regenerative capacity, architectural deterioration, and bone matrix quality, all of which could diminish implant fixation. Recent findings both in preclinical animal models and in clinical studies indicate encouraging results for the use of osteoporosis drugs to promote implant fixation. Implant fixation in osteoporotic bone presents an increasing clinical challenge that may be benefitted by increased screening and usage of osteoporosis drugs.

Hypovitaminosis D in the Greek Elderly Population Doesn't Concern Only Patients with Hip Fracture

Introduction

Vitamin D (VD) deficiency seems to be an underestimated public health issue, especially in countries with a significant duration of sunlight throughout the year, as in this sunny Mediterranean region where this cross-sectional observational study was held. This study was conducted to assess the hypothesis that a higher prevalence of hypovitaminosis D exists in the elderly population with a hip fracture as compared with patients with knee/hip osteoarthritis or lumbar spondylosis in a south-western Mediterranean region.

Methods

This study included 61 consecutive patients with a mean age of 83 years who sustained a hip fracture (Group A). Sixty patients, with an average age of 73 years, who suffered from degenerative hip/knee osteoarthritis or lumbar spondylosis were subsequently selected as the control group (Group B). Parathyroid hormone (PTH) and 25-hydroxy VD blood levels were measured.

Results

Ninety-six point seven percent (96.7%; 59/61) of the individuals with hip fracture and 81.7% (49/60) in the controls were found with abnormal VD values (<30 ng/ml). The comparison of vitamin D values between the total samples of group A and B revealed a statistically significant difference (unpaired t-test, p<0.0001) while both male (p=0.0049) and female (p<0.0001) individuals in group A also showed statistically significant lower VD levels than their counterparts did. In addition, increased levels of parathormone were observed in women of group A (p=0.0016) and, therefore, for group A in the total sample (p=0.0004) while no statistical significance was observed in males (p=0.7712). Age was found to be an independent risk factor for VD deficiency in both groups (Group A p=0.04, Group B p=0.043). It is noteworthy that only four patients from group B (6, 67%) and none from group A had undergone blood tests for VD and PTH evaluation before hospital admission.

Conclusions

Τhe results confirmed the initial hypothesis of the study. Although VD hypovitaminosis concerns the majority of elderly living in this south-western Mediterranean region, the authors suggest VD and PTH measurements regardless of annual insolation, to identify and counsel the elderly with an increased risk of hip fracture and to avoid perioperative complications in patients who undergo elective orthopedic surgeries.

Effect of donor age and 3D-cultivation on osteogenic differentiation capacity of adipose-derived mesenchymal stem cells

Background and Purpose: Age and co-morbidities compromise healing tendencies of traumatic fractures in geriatric patients. Non-healing fractures may need regenerative medicine techniques involving autologous mesenchymal stem cells (MSCs). Donor age may affect the viability and differentiation capacity of MSCs. We investigated age-related differences in adipose-derived MSCs (AMSCs) concerning osteogenic potential in 2D and 3D cultivation. Materials and Methods: AMSCs were harvested from young (mean age: 37.5 ± 8.6 years) and old (mean age: 75.8 ± 9.2 years) patients. Cells were induced to osteogenic differentiation and cultivated in 2D and 3D for 14 days. Alkaline phosphatase (ALP) activity, mineralization and gene expression were investigated. Results: ALP activity revealed highest levels in 3D of old AMSCs after 14 days. ALP expression showed significant rises in old vs. young cells in 2D (p = 0.0024). Osteoprotegerin revealed the highest levels in old AMSCs in 2D. Highest osteocalcin levels presented in young cells compared to old cells in 2D (p = 0.0258) and young cells in 3D (p = 0.0014). Conclusion: 3D arrangement of old AMSCs without growth factors is not ensuring superior osteogenesis in vitro. AMSCs, especially cells from older patients, reveal higher osteogenic potential in 2D than in 3D. 3D arrangement favors osteogenic potential of young cells.

Bone Health Optimization in Orthopaedic Surgery

BACKGROUND

Osteoporosis is associated with adverse orthopaedic surgical outcomes. Bone health optimization is a preoperative intervention intended to reduce the likelihood of postoperative complications. We aimed to characterize a patient cohort referred for bone health optimization to test the hypothesis that poor bone quality is common in orthopaedic surgery and that many such patients meet guidelines for osteoporosis treatment.

METHODS

This retrospective study evaluated 124 patients referred for bone health optimization who were ≥50 years of age and candidates for arthroplasty or thoracolumbar surgery. The Fracture Risk Assessment Tool (FRAX) risk factors and dual x-ray absorptiometry (DXA) results were collected. When available, opportunistic computed tomographic (CT) imaging and the trabecular bone score were evaluated. The World Health Organization (WHO) diagnostic and National Osteoporosis Foundation (NOF) treatment guidelines were applied.

RESULTS

All patients were referred by their orthopaedic surgeon; their mean age was 69.2 years, 83% of patients were female, 97% were Caucasian, and 56% had sustained a previous fracture. The mean historical height loss (and standard deviation) was 5.3 ± 3.3 cm for women and 6.0 ± 3.6 cm for men. The mean lowest T-score of the hip, spine, or wrist was -2.43 ± 0.90 points in women and -2.04 ± 0.81 points in men (p < 0.08). Osteoporosis (T-score of ≤-2.5 points) was present in 45% of women and 20% of men; only 3% of women and 10% of men had normal bone mineral density. Opportunistic CT scans identified 60% of patients as likely having osteoporosis. The trabecular bone score identified 34% of patients with degraded bone microarchitecture and 30% of patients with partially degraded bone microarchitecture. The NOF threshold for osteoporosis treatment was met in 91% of patients. Treatment was prescribed in 75% of patients (45% anabolic therapy and 30% antiresorptive therapy).

CONCLUSIONS

Osteoporosis, degraded bone microarchitecture, prior fracture, and elevated fracture risk were common. Given the high prevalence of impaired bone health in this cohort, we believe that bone health screening, including FRAX assessment, should be considered in selected patients undergoing orthopaedic surgery as part of the preoperative optimization for all adults who are ≥50 years of age.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Total Knee Arthroplasty in the Osteoporotic Tibia: A Biomechanical Evaluation of the Role of Stem Extensions and Cementing Techniques

INTRODUCTION

Poor functional outcomes and aseptic loosening increase when total knee arthroplasty is performed on osteoporotic patients. This biomechanical study evaluated the effect of stem extension on the stability of tibial fixation using different cementing techniques.

METHODS

A standard design tibial tray was implanted in a replica of a male osteoporotic tibia. Twenty-four implantations were performed using three variations of implant and cementing, and then mounted on a material testing machine load frame at 500 cycles of multiaxial loading simulating walking. The three-dimensional components of tray-tibia micromotion were measured.

RESULTS

The primary implant total interface motion with surface cementing was 25.9 μm ± 14.7 μm and 10.6 μm ± 7.6 μm with full cementing (P = 0.001). The three-dimensional motion of fully cemented primary implants with stem extension was 4.4 μm ± 3.9 μm, which represents a decrease in micromotion of 83% in surface cemented primary implants (P < 0.0001) and 58% in the fully cemented components without stem extension (P < 0.009).

CONCLUSION

Fully cemented primary implants with stem extensions demonstrated decreased micromotion and should be considered for use in osteoporotic total knee arthroplasty patients.

Effect of bisphosphonates on periprosthetic bone loss after total knee arthroplasty: a meta-analysis of randomized controlled trials

Background

Aseptic loosening and osteolysis are the most common indications after TKA for revision surgery. This meta-analysis which included high-quality randomized controlled trials (RCTs) aimed to analyze the effect of bisphosphonates (BPs) on maintaining periprosthetic bone mineral density (BMD) after total knee arthroplasty.

Methods

PubMed, AMED, EMBASE, the Cochrane library, ISI Web of Science, and China National Knowledge Infrastructure were systematically searched, five RCTs were included and the total number of participants was 188. The weighted mean differences with 95% confidence interval were calculated to evaluate the efficacy of BPs on total BMD of knee and the BMD of different periprosthetic regions. A descriptive review was performed for BP-related adverse effects.

Results

The BPs group presented significantly higher total BMD in proximal part of the tibia than the control group at 3 and 6 months (P < 0.05), but no significant difference at 12 months (P = 0.09). The BPs group presented significantly higher BMD in the distal aspect of the femur than that in the control group at 3, 6, 12 months. The BPs group presented significantly higher periprosthetic BMD than that in the control group at 3, 6 and 12 months in tibial medial and lateral metaphyseal region, and femoral anterior, central and posterior metaphyseal region (p < 0.05), but no significant difference for tibial diaphyseal region at 3, 6, and 12 months. None of the included studies described severe or fatal adverse effects related to BPs.

Conclusion

BPs have a short-term effect on reducing periprosthetic bone loss after total knee arthroplasty. Compared with diaphyseal region, BPs are more effective on the preservation of BMD in medial lateral metaphyseal regions of proximal tibia and in anterior, central, and posterior metaphyseal region of distal femur.

A numerical investigation and experimental verification of size effects in loaded bovine cortical bone

In this paper, we present 2- and 3-dimensional finite element-based numerical models of loaded bovine cortical bone that explicitly incorporate the dominant microstructural feature: the vascular channel or Haversian canal system. The finite element models along with the representation of the microstructure within them are relatively simple: 2-dimensional models, consisting of a structured mesh of linear elastic planar elements punctuated by a periodic distribution of circular voids, are used to represent beam samples of cortical bone in which the channels are orientated perpendicular to the sample major axis, while 3-dimensional models, using a corresponding mesh of equivalent solid elements, represent those samples in which the canals are aligned with the axis. However, these models are exploited in an entirely novel approach involving the representation of material samples of different sizes and surface morphology. The numerical results obtained for the virtual material samples when loaded in bending indicate that they exhibit size effects not forecast by either classical (Cauchy) or more generalized elasticity theories. However, these effects are qualitatively consistent with those that we observed in a series of carefully conducted experiments involving the flexural testing of bone samples of different sizes. Encouraged by this qualitative agreement, we have identified appropriate model parameters, primarily void volume fraction but also void separation and matrix modulus by matching the computed size effects to those we observed experimentally. Interestingly, the parameter choices that provide the most suitable match of these effects broadly concur with those we actually observed in cortical bone.

Total Ankle Arthroplasty for Rheumatoid Arthritis in Japanese Patients: A Retrospective Study of Intermediate to Long-Term Follow-up

Background:

Outcomes after total ankle arthroplasty (TAA) combined with additive techniques (augmentation of bone strength, control of soft-tissue balance, adjustment of the loading axis) for the treatment of rheumatoid arthritis were evaluated after intermediate to long-term follow-up. The influences of biologic treatment on the outcomes after TAA were also evaluated.

Methods:

We performed a retrospective observational study involving 50 ankles (44 patients) that underwent TAA for the treatment of rheumatoid arthritis. The mean duration of follow-up was 7.1 years. Clinical outcomes were evaluated with use of the Japanese Society for Surgery of the Foot (JSSF) scale score and a postoperative self-administered foot-evaluation questionnaire (SAFE-Q). Radiographic findings were evaluated as well. These parameters also were compared between patients managed with and without biologic treatment.

Results:

This procedure significantly improved the clinical scores of the JSSF rheumatoid arthritis foot and ankle scale (p < 0.0001). Forty-eight of the 50 ankles had no revision TAA surgery. Subsidence of the talar component was seen in 8 ankles (6 in the biologic treatment group and 2 in the non-biologic treatment group); 2 of these ankles (both in the biologic treatment group) underwent revision TAA. The social functioning score of the SAFE-Q scale at the time of the latest follow-up was significantly higher in the biologic treatment group (p = 0.0079). The dosage of prednisolone (p = 0.0003), rate of usage of prednisolone (p = 0.0001), and disease-activity score (p < 0.01) at the time of the latest follow-up were all significantly lower in the biologic treatment group.

Conclusions:

TAA is recommended for the treatment of rheumatoid arthritis if disease control, augmentation of bone strength, control of soft-tissue balance, and adjustment of the loading axis are taken into account. The prevention of talar component subsidence remains a challenge in patients with the combination of subtalar fusion, rheumatoid arthritis, and higher social activity levels.

Level of Evidence:

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Importance of Bone Mineral Density in Hip Arthroplasty: Results of a Survey Asking Orthopaedic Surgeons about Their Opinions and Attitudes Concerning Osteoporosis and Hip Arthroplasty

Objective. In patients scheduled to undergo total joint arthroplasty of the hip, the bone quality around the joint affects the safety of prosthetic implantation. Bone strength is clinically assessed by measuring bone mineral density (BMD); therefore we asked if BMD is important to orthopaedic surgeons performing hip arthroplasty. Methods. In a 14-question survey, we asked about treatment patterns with respect to BMD, osteoporosis work-up, and treatment for patients with low BMD scheduled to undergo hip arthroplasty. Results. 72% of all asked orthopaedics reported to use cementless implants as a standard in hip arthroplasty. Over 60% reported that low BMD is a reason to reconsider operation strategies, but only 4% performed BMD measurement preoperatively. 26% would change their treatment strategy in case of a BMD (T-Score) between −1.5 and −2 and 40% in case of a T-score between −2 and −2.5, and 29% would change their intraoperative strategy if a T-score smaller than −2.5 was measured. Conclusion. The majority of orthopaedic surgeons who responded to the survey reported that they do not perform routine measurement of BMD before arthroplasty. However, most surgeons commented that low bone mineral density will influence their surgical plan and the implant design.