Bone Mineral Density in the Proximal Femur and Contralateral Knee After Total Knee Arthroplasty

Osteoarthrosis (OA) is often associated with pain and disability, which are relieved after total knee arthroplasty (TKA), but the nature of bone changes associated with OA is controversial. We examined preoperative hip and contralateral knee bone mineral density (BMD) in patients requiring TKA and monitored the BMD changes postoperatively. Sixty-nine patients, scheduled to have TKA for osteoarthrotic knees, had both hips and contralateral knee BMD measured by dual-energy X-ray absorptiometry (DXA) at the time of operation (baseline) and at 1 yr after operation. X-rays of the knee joints were also taken to evaluate the severity of OA. Preoperatively, 27% and 38% of the patients had total hip BMD Z-score more than 1 SD in the operated side and contralateral hips, respectively. In all regions of interest (ROI), the mean baseline BMD of the affected side proximal femur was significantly lower than that of the contralateral side (p < 0.0005-0.019). The severity of OA was not associated with BMD. During 1-yr follow-up, the postoperative knee status and the physical activity of the patients (AKS score) improved. However, neither the hip nor the nonoperated knee BMDs increased. Knee OA is associated with significantly lower BMD values in the affected side compared with the contralateral hip, and these levels remained similar or decreased during a 1-yr follow-up. We conclude that improved mobility after TKA does not improve the effects of preoperative disuse-associated bone loss in the short term.     

Changes in Bone Mineral Density of the Acetabulum and Proximal Femur After Total Hip Resurfacing Arthroplasty

Our aim was to investigate the changes in bone mineral density (BMD) of acetabulum and proximal femur after total hip resurfacing arthroplasty. A comparative study was carried out on 51 hips in 48 patients. Group A consisted of 25 patients (26 hips) who had undergone total hip resurfacing and group B consisted of 23 patients (25 hips) who had had large-diameter metal-on-metal total hip arthroplasty (THA). BMDs around the acetabulum and proximal femur were measured using dual-energy x-ray absorptiometry (DEXA) at 2 weeks, 6 months, 1 year and annually thereafter during the 3 years after surgery. At final follow-up, the acetabular net mean BMD decreased by 11% in group A and 10% in group B with no differences between two groups (P = .35). For the femoral side, in Gruen zone 1, the mean BMD increased by 4% in group A, whereas it decreased by 11% in group B (P = .029). In Gruen zone 7, the mean BMD increased by 8% at the final follow-up in group A, whereas it decreased by 13% in group B (P = .02). In both groups the mean BMD increased by 3% in Gruen zones 3, 4, 5, and 6. Stress-related bone loss of the acetabulum was comparable for MOM THA and resurfacing devices, but proximal femoral bone density increased in the resurfacing group and decreased in the THA group.     

Changes in Bone Mineral Density of Both Proximal Femurs after Total Knee Arthroplasty

Background

This study investigated the effects of total knee arthroplasty (TKA) on bone mineral density (BMD) of the proximal femur in patients who underwent the procedure.

Methods

Forty-eight patients scheduled to undergo unilateral TKA because of primary knee osteoarthritis were included in this study, which was conducted at a medical center between October 2006 and October 2009. In these 48 patients, 96 hips were evaluated. Measurement of BMD was performed preoperatively and one month, three months, six months, and one year after unilateral TKA. Repeated measured analysis of variance and paired t-tests for comparison of two repeated samples were used to compare differences between time points (preoperation, one, three, six, and 12 months) and between the operative and nonoperative sides.

Results

Preoperatively, BMD of the femoral neck, trochanter, and total hip on the operative side were lower than on the nonoperative side; however, there was no statistical difference. BMD of both femoral neck areas was significantly lower than preoperative BMD at one month and three months after TKA. BMD of both trochanter areas was significantly lower than preoperative BMD at one month and three months after TKA. BMD of both total hips was significantly lower than preoperative BMD at three months after TKA. However, no statistical differences of changes in BMD were observed between the operative and nonoperative sides at each measurement time.

Conclusions

According to our results, TKA was found to affect both proximal femurs during the acute period. However, TKA did not affect a change in BMD of the proximal femur during one year postoperative.     

Bone Mineral Density of the Femur in Autopsy Retrieved Total Knee Arthroplasties

Bone mineral density (BMD), as measured by DEXA, can vary depending on bone rotation and fat content of soft tissues. We performed DEXA measurements, under controlled positioning, on 24 autopsy-retrieved femora from patients who had fully functional and asymptomatic successful TKA to determine periprosthetic BMD changes and compared results to 24 normal cadaveric femora. In TKA specimens, BMD was affected by gender, preoperative diagnosis, and zone under analysis. The lowest mean BMD was in the anterior femoral condylar zone. Males had higher mean BMD at all zones while patients with preoperative diagnosis of osteoarthritis had higher BMD in the posterior condylar zone. The mean BMD in the anterior femoral condylar zone in TKA specimens was significantly lower than in normal specimens without arthroplasties, most likely due to stress shielding.     

Teriparatide Administration Increases Periprosthetic Bone Mineral Density After Total Knee Arthroplasty: A Prospective Study

Background

Teriparatide is a currently available therapeutic agent for osteoporosis. Previous studies have reported that teriparatide affects periprosthetic bone mineral density (BMD) after total knee arthroplasty (TKA). However, little agreement has been reached concerning the treatment of periprosthetic BMD after TKA with teriparatide. Moreover, BMD in the femoral and tibial sides of the joints together has never been examined. We investigated the efficacy of teriparatide to inhibit BMD loss in the femoral and tibial side and considered complications such as migration and periprosthetic fractures after TKA.

Outcomes of a First Total Knee Arthroplasty Are Associated With Outcomes of the Subsequent Contralateral Total Knee Arthroplasty

BackgroundTo determine if preoperative characteristics and postoperative outcomes of a first total knee arthroplasty (TKA) were predictive of characteristics and outcomes of the subsequent contralateral TKA in the same patient.MethodsRetrospective administrative claims data from (SPARCS) database were analyzed for patients who underwent sequential TKAs from September 2015 to September 2017 (n = 5,331). Hierarchical multivariable Poisson regression (length of stay [LOS]) and multivariable logistic regression (all other outcomes), controlling for sex, age, and Elixhauser comorbidity scores were performed.ResultsThe cohort comprised 65% women, with an average age of 66 years and an average duration of 7.3 months between surgeries (SD: 4.7 months). LOS was significantly shorter for the second TKA (2.6 days) than for the first TKA (2.8 days; P < .001). Patients discharged to a facility after their first TKA had a probability of 76% of discharge to facility after the second TKA and were significantly more likely to be discharged to a facility compared with those discharged home after the first TKA (odds ratio [OR]: 63.7; 95% confidence interval [CI]: 52.1-77.8). The probability of a readmission at 30 and 90 days for the second TKA if the patient was readmitted for the first TKA was 1.0% (OR: 3.70; 95% CI: 0.98-14.0) and 6.4% (OR: 9; 95% CI: 5.1-16.0), respectively. Patients with complications after their first TKA had a 27% probability of a complication after the second TKA compared with a 1.6% probability if there was no complication during the first TKA (OR: 14.6; 95% CI: 7.8.1-27.2).ConclusionThe LOS, discharge disposition, 90-day readmission rate, and complication rate for a second contralateral TKA are strongly associated with the patient’s first TKA experience. The second surgery was found to be associated with an overall shorter LOS, fewer readmissions, and higher likelihood of home discharge.Level of EvidenceLevel 3-retrospective cohort study.     

Acute Postoperative Herpes Zoster With a Sciatic Nerve Distribution After Total Joint Arthroplasty of the Ipsilateral Hip and Contralateral Knee

The differential diagnosis of a patient with acute onset of hip pain during the postoperative recovery period after total hip arthroplasty includes sciatic nerve injury, infection, incisional pain, hardware, or simply muscular issues related to overactivity. Moreover, because the rash of herpes zoster develops after 4 or 5 days of pain, it is difficult to diagnose herpes zoster during the early period. A number of reports have been issued on herpes zoster after surgery or trauma, but no report is available on herpes zoster development with a sciatic nerve distribution after ipsilateral total hip arthroplasty. The authors report the case of 75-year-old woman with herpes zoster with a sciatic nerve distribution after 2 primary total joint arthroplasties of a hip and knee.     

Chronic Thrombocytopenia and In-Hospital Outcomes After Primary Total Hip and Knee Arthroplasty

BackgroundThere is a lack of data on the influence of chronic thrombocytopenia (cTCP) on clinical outcomes following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). Limited studies mainly focused on postoperative heparin-induced TCP from single centers with small sample sizes. This study aims to describe the characteristics, trend, and outcomes of cTCP in patients undergoing THA and TKA from a nationally reprehensive perspective.MethodsWe identified THA and TKA patients with and without cTCP from the 2005 to 2015 Nationwide Inpatient Sample. Annual percent changes were calculated to reflect cTCP trends. Multivariable regression and propensity score analyses were conducted to investigate the association of cTCP and mortality, preoperative complications, cost as well as length of stay.ResultsIn total, 578,278 and 1,237,331 patients underwent primary THA and TKA, respectively. Proportion of cTCP annually increased by 6.95% in THA and 6.66% in TKA. Patients with cTCP were associated with higher risk of medical (odds ratio [OR] 2.00, 95% confidence interval [CI] 1.89-2.11) and surgical complications (OR 2.72, 95% CI 2.55-2.90) in THA, and higher risk of mortality (OR 1.68, 95% CI 1.22-2.31), medical (OR 1.94, 95% CI 1.85-2.03) and surgical complications (OR 2.55, 95% CI 2.38-2.73) in TKA. Additionally, higher cost and longer length of stay were observed in patients with cTCP for both surgical procedures.ConclusionPatients with cTCP had higher risk of mortality for TKA, more perioperative complications for both TKA and THA. Further studies are warranted to improve the preoperative management and to prevent worse outcomes associated with cTCP.     

骨矿改变在人工全髋关节置换术的监测

目的：研究人工全髋关节置换术后髋周骨矿含量的改变。方法：对骨水泥型人工全髋关节置换的25例27髋,在术后不同时段用DEXA测定髋周5个区域的骨矿含量,并与其各自合适的对照作配对样本t检验。结果：术后1个月内（平均23d)测定组显示第4区骨矿量显著增加（P＜0．05）;术后4－6月（平均4．4月）和7－12月测定组显示5个区骨矿量无显著增减（P＞0．05）;术后14－49月（平均27．4月）测定组显示第2区和第5区骨矿量显著降低（P＜0．05）;第1区也有明显降低趋势（P＝0．064）。结论：骨水泥型人工全髋置入后髋周承重部位骨矿量在12月内改变不大;术后约2年在髋臼周围和股骨小粗隆部骨矿明显丢失,与置入假体后产生应力遮挡可能有关。     

Causes of Instability After Total Knee Arthroplasty

The purpose of the present study was to characterize the underlying causes that lead to instability after total knee arthroplasty (TKA). We reviewed 83 revision TKAs (79 patients) performed for instability. After detailed analysis of patient's history, physical examination, operative report and radiographs, we identified six categories: flexion/extension gap mismatch, component malposition, isolated ligament insufficiency, extensor mechanism insufficiency, component loosening, and global instability. Twenty-five knees presented with multi-factorial instability. When these knees were classified according to the most fundamental category, each category above included 24, 12, 11, 10, 10 and 16 knees respectively. The unstable TKA may result from a variety of distinct etiologies which must be identified and treated at the time of revision. The revision TKA could be tailored to the specific causes.     

Bone Defects in Revision Total Knee Arthroplasty and Management

This article reviews the recent updates in revision of total knee arthroplasty (RTKA). We reviewed the recent articles on RTKA in databases including PubMed, Google Scholar, and SCOPUS. Total knee arthroplasty (TKA) involves the replacement of all three compartments of the knee in surgery of the knee joint to restore capacity and function. TKA is one of the most common and reliable surgical treatment options for the treatment of knee diseases. However, some patients require revision of TKA (RTKA) after primary TKA for various reasons, including mechanical wear, implant loosening or breakage, malalignment, infection, instability, periprosthetic fracture, and persistent stiffness. Unfortunately, the overall outcome of RTKA is not as satisfactory as for primary TKA due to the uncertainty regarding the actual success rate and the risk factors for failure. Cementation, modular metal augmentation, bone grafting, autologous bone grafting, allogenic bone grafting, impactation bone grafting, structural bone allografting, metaphyseal fixation, using porous titanium coated press fit metaphyseal sleeves and porous tantalum structural cones, and megaprostheses or customized prostheses are the currently available management options for RTKA. However, most of the management systems possess specific complications. Novel approaches should be developed to improve functional capacity, implant survival rates, and quality of life in a cost‐efficient manner.     

Stiffness After Revision Total Knee Arthroplasty

Stiffness after a revision total knee arthroplasty (TKA) is a disabling complication that has largely been overlooked in the literature. This study attempts to define the prevalence of stiffness after revision TKA and to determine the risk factors that may lead to its development. Thirty-two knees (4.0%) presented with stiffness that we defined as a range of motion less than 90°. Risk factors were found to be poor preoperative range of motion, stiffness as primary indication for revision, younger age, shorter interval between index primary and revision TKA, presence of well-fixed components at the time of revision, postoperative wound drainage, and lower Charlson index. Because of the challenges of treating stiffness, efforts should be invested in preventing this complication.     

Joint Mechanics After Total Knee Arthroplasty While Descending Stairs

Background

Modern knee designs do not fully restore the anatomy and kinematics of the natural knee. This study evaluates the kinematic and kinetic changes of well-functioning patients with total knee arthroplasty (TKA) in comparison to a healthy age-matched control group while descending stairs and level walking. The aim was to have a baseline for further investigations of TKA patients with problems.

Topical Administration of Tranexamic Acid in Primary Total Hip and Total Knee Arthroplasty

Major blood loss is a known potential complication in total hip and total knee arthroplasty. We conducted a prospective, stratified, randomized, double-blind, placebo-controlled trial that evaluated 100 patients undergoing total knee or total hip arthroplasty to evaluate the effect on blood loss using the topical application of tranexamic acid. Participants received either 2 g of topical tranexamic acid or the equivalent volume of placebo into the joint prior to surgical closure. Tranexamic acid resulted in a lower mean maximum decline in postoperative hemoglobin levels when compared to placebo (P = 0.013). Patients in the tranexamic acid group demonstrated an improved but non-significant reduction in the units of blood transfused compared to placebo (P = 0.423). There was no clinically significant increase in complications in the tranexamic acid group, including no incidence of venous thromboembolism.     

Relationships Between Preoperative Mental Health and Improvements in Patient-Reported Outcomes After Total Hip and Knee Arthroplasty

BackgroundPoor preoperative mental health has been associated with worse outcomes after total hip (THA) and total knee arthroplasty (TKA). To fully understand these relationships, we assessed post-THA and post-TKA improvements in patient-reported mental and joint health by preoperative mental health groups.MethodsElective cases (367 THA, 462 TKA) were subgrouped by low (<25th percentile), middle (25th-74th), and high (≥75th) preoperative mental health, using Veterans RAND 12-Item Health Survey Mental Component Summary (MCS) scores. In each subgroup, we assessed the relationship between preoperative MCS and 1-year postoperative change in mental and joint health. Pairwise comparisons and multivariable regression models were applied for THA and TKA separately.ResultsMedian postoperative mental health change was +14.0 points for the low-MCS THA group, +11.1 low-TKA, +2.0 middle-THA and TKA, −4.0 high-THA, and −4.9 high-TKA (between-group differences P < .001). All MCS groups had improved median joint health scores, without significant between-group differences. Preoperative mental health was negatively associated with mental health improvements in all groups (B = −0.94 - −0.68, P < .001-P = .01) but with improvements in joint health only in the low-THA group (B = −0.74, P = .02). Improvements in mental and joint health were positively associated for low and middle (B = 0.61-0.87, P < .001), but not for high-MCS groups, with this relationship differing for the low versus high group.ConclusionPatients who have low preoperative mental health experienced greater postoperative mental health improvement and similar joint health improvement compared to patients who have high preoperative mental health. Findings can guide subgroup-targeted surgical decision-making and preoperative counseling.     

The Cost of Stiffness After Total Knee Arthroplasty

BackgroundStiffness after primary total knee arthroplasty (TKA) is debilitating and poorly understood. A heterogenous approach to the treatment is often utilized, including both nonoperative and operative treatment modalities. The purpose of this study was to examine the prevalence of treatments used between stiff and non-stiff TKA groups and their financial impact.MethodsAn observational cohort study was conducted using a large database. A total of 12,942 patients who underwent unilateral primary TKA from January 1, 2017, to December 31, 2017, were included. Stiffness after TKA was defined as manipulation under anesthesia and a diagnosis code of stiffness or ankylosis, and subsequent diagnosis and procedure codes were used to identify the prevalence and financial impact of multiple common treatment options.ResultsThe prevalence of stiffness after TKA was 6.1%. Stiff patients were more likely to undergo physical therapy, medication, bracing, alternative treatment, clinic visits, and reoperation. Revision surgery was the most common reoperation in the stiff TKA group (7.6%). The incidence of both arthroscopy and revision surgery were higher in the stiff TKA population. Dual component revisions were costlier for patients who had stiff TKAs ($65,771 versus $48,287; P < .05). On average, patients who had stiffness after TKA endured costs from 1.5 to 7.5 times higher than the cost of their non-stiff counterparts during the 2 years following index TKA.ConclusionPatients who have stiffness after primary TKA face significantly higher treatment costs for both operative and nonoperative treatments than patients who do not have stiffness.     

Total Patellar Skin Loss From Cryotherapy After Total Knee Arthroplasty

The use of cryotherapy after total knee arthroplasty is a very common therapeutic adjunct accepted as routine postoperative care. We present 2 cases of total patellar skin loss due to cryotherapy after total knee arthroplasty. Substantial soft tissue defects were created after the initial debridement of the necrotic tissue. Both patients were evaluated for frostbite, and the wounds were sharply debrided. Application of an advanced wound management technique involves the use of a collagen-glycosaminoglycan biodegradable bilayer matrix, silver impregnated antimicrobial dressing, and low-pressure vacuum device, followed by delayed split thickness skin grafting and low-pressure vacuum device. We find that this technique provided durable soft tissue coverage for necrotic wounds of the knee that do not involve the joint capsule.