Does bone quality predict loosening of cemented total hip replacements?

Cemented Versus Cementless Femoral Fixation for Total Hip Arthroplasty Following Osteoarthritis

BACKGROUND

The mode of femoral fixation for primary total hip arthroplasty (THA) is undetermined, with reported outcomes favoring different fixation methods. This study aimed to compare postoperative complications between cemented and cementless fixation at 90 days, 1 year, and 2 years in patients aged 65 years of age and older undergoing THA for osteoarthritis.

METHODS

Using an all-payer, national database, patients 65 years and older undergoing primary THA, either with cementless (n = 56,701) or cemented (n = 6,283) femoral fixation for osteoarthritis were identified. A 1:1 propensity-matched analysis for age, sex, comorbidity index, alcohol abuse, tobacco use, obesity, and diabetes was performed, resulting in n = 6,283 patients in each cohort. Postoperative outcomes, including postoperative periprosthetic joint infection, aseptic revision, surgical site infection, pulmonary embolism, venous thromboembolism, wound complications, dislocation, periprosthetic fracture, and aseptic loosening were assessed.

RESULTS

The cemented cohort had higher rates of infection (4.5 versus 0.8%, odds ratio [OR] 5.9, 95% confidence interval [CI] 4.33 to 7.93, P < .001), aseptic revision (2.9 versus 2.0%, OR 1.47, 95% CI 1.17 to 1.85, P = .001), venous thromboembolism (1.8 versus 1.3%, OR 1.40, 95% CI 1.05 to 1.87, P < .001), and aseptic loosening (1.5 versus 0.7%, OR 2.31, 95% CI 1.60 to 3.32, P < .001) at 90-days. At 1 and 2 years, the cemented cohort had higher rates of infection, aseptic revision, and aseptic loosening (all P < .001). Rates of periprosthetic fracture were similar at all time points (all P < .001).

CONCLUSIONS

Cemented fixation had higher rates of infection, aseptic loosening, and aseptic revision. This finding supports the current use of cementless fixation, but the ultimate decision regarding fixation type should be based on the proper optimization of the patient's comorbidities and bone quality.

Total hip arthroplasty in patients under 50 years old: Does cementless fixation have better results?

BACKGROUND

Cementless fixation for hip arthroplasties has increased in the last decades, particularly in younger patients. The purpose of this study was to compare the long-term results three different types of fixations in patients under 50years old.

METHODS

Cemented, hybrid and cementless fixations were assessed in patients under 50years old with a minimum follow-up of 8years. Loosening, demarcation, complications, and prosthesis survival were assessed. Functional analysis was performed with the modified Harris Hip Score and Visual analogue scale was collected.

RESULTS

Final series consisted in 222 patients. Significant improvement was observed regarding mHHS and VAS score in each group. We observed statistically significant difference regarding demarcation between the groups (P<.001). The higher rate of acetabular and femoral stem loosening was observed in the cemented (20.0%) and hybrid (18.9%) group. The lowest prosthesis survival rate after 16 years was observed in hybrid group (P<.001).

CONCLUSION

Total hip replacement has good long-term clinical and functional outcomes. The lowest rate of prosthesis survival was observed in hybrid group with 84.2% after 16years.

Smoking is associated with higher short-term risk of revision and mortality following primary hip or knee arthroplasty: a cohort study of 272,640 patients from the Dutch Arthroplasty Registry

BACKGROUND AND PURPOSE

Patients actively smoking at the time of primary hip or knee arthroplasty are at increased risk of direct perioperative complications. We investigated the association between smoking status and risk of revision and mortality within 2 years following hip or knee arthroplasty.

METHODS

We used prospectively collected data from the Dutch Arthroplasty Register. All primary total hip arthroplasties (THAs), total knee arthroplasties (TKAs), and unicondylar knee arthroplasties (UKAs) with > 2 years' follow-up were included (THA: n = 140,336; TKA: n = 117,497; UKA: n = 14,807). We performed multivariable Cox regression analyses to calculate hazard risks for differences between smokers and non-smokers, while adjusting for confounders (aHR).

RESULTS

The smoking group had higher risk of revision (THA: aHR 1.3, 95% confidence interval [CI] 1.1-1.4 and TKA: aHR 1.4, CI 1.3-1.6) and risk of mortality (THA: aHR 1.4, CI 1.3-1.6 and TKA: aHR 1.4, CI 1.2-1.6). Following UKA, smokers had a higher risk of mortality (aHR 1.7, CI 1.0-2.8), but no differences in risk of revision were observed. The smoking group had a higher risk of revision for infection following TKA (aHR 1.3, CI 1.0-1.6), but not following THA (aHR 1.0, CI 0.8-1.2).

CONCLUSION

This study showed that the risk of revision and mortality is higher for smokers than for non-smokers in the first 2 years following THA and TKA. Smoking could contribute to complications following primary hip or knee arthroplasty.

Influence of bone mineral density on femoral stem subsidence after cementless THA

INTRODUCTION

Femoral stem subsidence can lead to aseptic loosening after total hip arthroplasty (THA). Low bone mineral density (BMD) is a risk factor for stem subsidence as it can affect the initial stability and osteointegration. We evaluated whether reduced bone mineral density is related to higher subsidence of the femoral stem after primary cementless THA with enhanced recovery rehabilitation.

METHODS

79 patients who had undergone primary cementless THA with enhanced recovery rehabilitation were analyzed retrospectively. Subsidence of the femoral stem was measured on standing pelvic anterior-posterior radiographs after 4-6 weeks and one year. Patient individual risk factors for stem subsidence (stem size, canal flare index, canal fill ratio, body mass index (BMI), demographic data) were correlated. Dual X-ray absorptiometry (DXA) scans were performed of the formal neck and the lumbar spine including the calculation of T-score and Z-score. Patient-reported outcome measures were evaluated 12 months postoperatively.

RESULTS

Stem subsidence appeared regardless of BMD (overall collective 2.3 ± 1.64 mm). Measure of subsidence was even higher in patients with normal BMD (2.8 ± 1.7 mm vs. 2.0 ± 1.5 mm, p = 0.05). High BMI was correlated with increased stem subsidence (p = 0.015). Subsidence had no impact on improvement of patient-related outcome measures (WOMAC, EQ-5D-5L and EQ-VAS) after THA. Patients with low BMD reported lower quality of life 12 month postoperatively compared to patients with normal BMD (EQ-5D-5L 0.82 vs. 0.91, p = 0.03).

CONCLUSION

Stable fixation of a cementless stem succeeds also in patients with reduced BMD. Regarding stem subsidence, enhanced recovery rehabilitation can be safely applied in patients with low BMD.

Association of osteoporosis and high serum homocysteine levels with intraoperative periprosthetic fracture during total hip arthroplasty: a propensity-score matching analysis

INTRODUCTION

Intraoperative periprosthetic fracture, one of the most frequent complications of total hip arthroplasty, is a very important factor that affects rehabilitation, hospitalization time, and cost of treatment. Osteoporosis is common in total hip arthroplasty patients and likely contributes to the increasing incidence of periprosthetic fracture. Despite this awareness, preoperative and postoperative osteoporosis evaluations remain insufficient. The purpose of this study was to evaluate the relationships between the occurrence of intraoperative periprosthetic fractures and both bone mineral density (BMD) and osteoporosis-related biomarkers.

MATERIALS AND METHODS

This single-center retrospective study included a total of consecutive 487 hip joints of patients with a mean age of 65.5 ± 11.8 years who underwent total hip arthroplasty between July 2017 and December 2020. Patients with low BMD defined as T-score < -1.0 versus those with normal BMD were matched by a 1:1 propensity score to balance for patient baseline characteristics, and outcome was analyzed by a modified Poisson regression model. Our primary outcome was the incidence of intraoperative periprosthetic fracture during surgery. We also investigated the effect modification of osteoporosis-related biomarkers, including tartrate-resistant acid phosphatase 5b (TRACP-5b), total procollagen type 1 amino-terminal propeptide (total P1-NP), intact parathyroid hormone (intact PTH), and homocysteine, on osteoporosis and outcomes.

RESULTS

After matching, 250 patients were analyzed. The risk of fracture was significantly higher in patients with low BMD than in normal BMD patients (Incidence rate ratio 5.00 [95% CI 1.11-22.43], p = 0.036). We also observed significant effect of high serum homocysteine on the occurrence of intraoperative fractures (Incidence rate ratio 8.38 × 106 [95% C; 3.44 × 106-2.01 × 107], p < 0.01).

CONCLUSION

Preoperative osteoporosis and high serum homocysteine levels were risk factors for intraoperative periprosthetic fractures.

LEVEL OF EVIDENCE

III, A single-center retrospective study.

The prevalence and treatment of osteoporosis in patients undergoing total hip arthroplasty and the levels of biochemical markers of bone turnover

AIMS

Osteoporosis is common in total hip arthroplasty (THA) patients. It plays a substantial factor in the surgery's outcome, and previous studies have revealed that pharmacological treatment for osteoporosis influences implant survival rate. The purpose of this study was to examine the prevalence of and treatment rates for osteoporosis prior to THA, and to explore differences in osteoporosis-related biomarkers between patients treated and untreated for osteoporosis.

METHODS

This single-centre retrospective study included 398 hip joints of patients who underwent THA. Using medical records, we examined preoperative bone mineral density measures of the hip and lumbar spine using dual energy X-ray absorptiometry (DXA) scans and the medications used to treat osteoporosis at the time of admission. We also assessed the following osteoporosis-related biomarkers: tartrate-resistant acid phosphatase 5b (TRACP-5b); total procollagen type 1 amino-terminal propeptide (total P1NP); intact parathyroid hormone; and homocysteine.

RESULTS

The prevalence of DXA-proven hip osteoporosis (T-score ≤ -2.5) among THA patients was 8.8% (35 of 398). The spinal osteoporosis prevalence rate was 4.5% (18 of 398), and 244 patients (61.3%; 244 of 398) had osteopenia (-2.5 < T-score ≤ -1) or osteoporosis of either the hip or spine. The rate of pharmacological osteoporosis treatment was 22.1% (88 of 398). TRACP-5b was significantly lower in the osteoporosis-treated group than in the untreated group (p < 0.001).

CONCLUSION

Osteoporosis is common in patients undergoing THA, but the diagnosis and treatment for osteoporosis were insufficient. The lower TRACP-5b levels in the osteoporosis-treated group - that is, osteoclast suppression - may contribute to the reduction of the postoperative revision rate after THA.Cite this article: Bone Joint Res 2022;11(12):873-880.

Biomechanical performance of the cemented acetabular cup with combined effects of bone quality, implant material combinations and bodyweight

The objective of this study is to understand the combined effects of bone quality, implant materials and bodyweight on the biomechanical performance of cemented acetabular cup. Additionally, the performance of the cemented acetabular cup was evaluated for obesity cases or obese people. A total of 84 FE models (based on CT data) were developed based on combinations of three different cancellous bone material distributions to represent bone quality, four different implant material combinations and seven different bodyweights. The biomechanical performance of the acetabular cup was evaluated based on bone stress (both cortical and cancellous bone), cement mantle stress, micromotion and contact pressure between the acetabular cup and femoral head. Cortical bone stress, cancellous bone stress, cement stress, the contact pressure between implants and micromotion between implants are affected by different bone quality, implant material combinations and bodyweights. An increase in bodyweight would increase the cortical bone stress, cancellous bone stress, cement stress, contact pressure between implants and micromotion between implants. However, bodyweight affects the cortical and cancellous bone stress more (stiff rise of the bone stresses; nonlinear relation) as compared to other output parameters (mostly linear relation). Comparing cortical and cancellous bone stress, the stress versus bodyweight curve is much stiffer (stiff rise in the curve) for cortical bone than cancellous bone and that even further increases as bone quality decreases. Especially considering obesity cases or obese people (very high bodyweight), the performance of the cemented acetabular component is poor.

Graphical abstract

[Formula: see text]

Metal and composite bone plates for B1 periprosthetic femoral fracture in healthy and osteoporotic condition: A comparative biomechanical study

The major concern after total hip arthroplasty (THA) is the incidence of periprosthetic fracture in the weaker bone, which can lead to subsequent revision surgery. Achieving the suitable fixation without affecting the stability of the well-fixed prosthesis remains controversial. Most of the studies examined the behavior of the Periprosthetic Fracture (PF) fixation (Vancouver “B1” type) through computational and experimentation on healthy bone condition with metal plates. The aim of the present study is to analyze the influences of the metal and composite bone plate PF fixation on the axial and shear movement at the fracture site. The PF fixation constructs were modeled with medical graded stainless-steel plate (construct A), titanium plate (construct B) and carbon/epoxy composite bone plate (construct C) with 12 holes and a 4 mm fracture gap. Analysis was carried out for all the stages (stage 1—Normal bone, stage 2—THA, stage 3—Immediate Post-Operative (IPO), stage 4—Post-Operative (PO) and, stage 5—Healed Bone (HB)) under various loadings for intact and osteoporosis conditions. The results showed higher stress in cortical bone for stage 3, whereas in all the other stages lower stresses were experienced in the cortical and cancelous bone under peak load in construct C for osteoporosis model compared with other constructs. The present study suggested the construct C may be suitable for osteoporosis bone conditions.

Total knee arthroplasty in patients with haemophilic arthropathy is effective and safe according to the outcomes at a mid-term follow-up

BACKGROUND

Haemophilic arthropathy (HA), a common complication of haemophilia, is secondary to recurrent joint bleeding and increases the prevalence of end-stage osteoarthritis (OA). Total knee arthroplasty (TKA) is a reliable treatment for haemophilia patients. This study was performed to evaluate the mid-term outcomes of TKA for end-stage HA. We hypothesized that the rate of complications of TKA is higher for patients with haemophilia than for patients without haemophilia.

METHODS

Patients with HA undergoing TKA from January 2015 to December 2016 in our centre were retrospectively reviewed. All patients were managed by a multidisciplinary team. The improvements in flexion contracture, range of motion (ROM), Knee Society Score (KSS; clinical and functional), Visual Analogue Scale (VAS) score, and satisfaction at final follow-up were analysed to evaluate the effectiveness of TKA in HA. The complications were analysed to evaluate the safety of TKA in HA.

RESULTS

Twenty-eight patients (32 knees) were included in the study. The follow-up was 69.1 ± 5.1 months. Significant differences between the preoperative and final follow-up values of flexion contracture (which changed from 21.1 ± 6.5° to 14.3 ± 4.1°, P < 0.001), ROM (from 53.9 ± 15.0° to 70.3 ± 16.3°, P < 0.001), clinical KSS (from 33.5 ± 14.4° to 62.7 ± 9.5°, P < 0.001), functional KSS (from 46.1 ± 15.5° to 62.9 ± 9.7°, P < 0.001), and VAS score (from 6.8 ± 1.4 to 4.9 ± 1.3, P < 0.01) were observed. Importantly, the incidence of complications was 15.6% and the satisfaction was 100% in our mid-term study.

CONCLUSION

Under elaborative and comprehensive management, TKA is effective and safe in patients with advanced HA on the basis of mid-term follow-up outcomes.

Abaloparatide Effects on Cortical Volumetric BMD and Estimated Strength Indices of Hip Subregions by 3D-DXA in Women With Postmenopausal Osteoporosis

In ACTIVE, abaloparatide increased areal BMD (aBMD) of the hip and femoral neck vs teriparatide and placebo in women with osteoporosis. Previously, 3D-processing of dual X-ray absorptiometry (DXA) scans of a subgroup of ACTIVE subjects showed similar increases in trabecular volumetric BMD (Tb.vBMD) and greater increases in cortical vBMD (Ct.vBMD) of the total hip with abaloparatide vs teriparatide. The current analyses from this subgroup describe 2D- and 3D-DXA data for hip subregions. Randomly selected subjects from ACTIVE (n = 250/treatment group) who received 18 mo of placebo, abaloparatide 80 µg, or open-label teriparatide 20 µg by daily subcutaneous injection underwent hip DXA at baseline, and mo 6 and 18 of treatment. Areal BMD of the femoral neck, trochanter, and femoral shaft was determined using standard 2D-DXA and 3D-SHAPER software to retrospectively evaluate changes from baseline in volumetric parameters of these 3 hip subregions, including trabecular and cortical segmentation. Changes in biomechanical parameters cross-sectional moment of inertia (CSMI), section modulus (Z), and buckling ratio were also evaluated. Femoral neck, trochanter, and shaft aBMD increased in the abaloparatide and teriparatide groups at mo 6 and 18 vs placebo, with greater increases for abaloparatide vs teriparatide at the femoral neck at mo 6 and the shaft at mo 6 and 18. All 3 subregions showed similar significant increases in Tb.vBMD with abaloparatide and teriparatide vs placebo, whereas Ct.vBMD of all 3 subregions showed greater increases after 18 mo of abaloparatide vs teriparatide. Biomechanical parameters improved in all subregions with abaloparatide and teriparatide vs placebo, with greater improvements in CSMI and Z of the femoral neck and lower shaft after 6 and 18 mo of abaloparatide vs teriparatide. Differential femoral neck and shaft Ct.vBMD responses may explain the greater increases in CSMI and Z of those subregions with abaloparatide vs teriparatide.

Zoledronic Acid Ameliorates the Bone Turnover Activity and Periprosthetic Bone Preservation in Cementless Total Hip Arthroplasty

The administration of zoledronic acid (ZA) to patients who received cementless total hip arthroplasty (THA) has been reported to reduce bone turnover markers (BTMs) and increase bone mineral density (BMD). The effects of two-dose ZA versus placebo on cementless THA patients were analyzed in this five-year extension study. Alkaline phosphatase (ALP), osteocalcin (OC), procollagen 1 intact N-terminal propeptide (P1NP), serum calcium, renal function, radiological findings, and functional outcomes were compared in 49 patients, and the periprosthetic BMD of seven Gruen zones were compared in 19 patients. All the patients had normal renal function and calcium levels at their final follow-up. The mean ALP level in the ZA group was significantly lower at the fifth year, mean OC levels were significantly lower at the second and fifth year, and mean P1NP levels were significantly lower from 6 weeks to 5 years as compared with the control group. Fifth-year BMD levels were not found to be different between the ZA and control groups. The BMD Change Ratios in the ZA group were significantly increased in Gruen zone 6 at 1, 2, and 5 years. Our study results suggest that short-term ZA treatment with a subsequent 4-year drug holiday may inhibit serum BTMs and provide periprosthetic bone preservation at five years without adverse events.

Additive Effect of Parathyroid Hormone and Zoledronate Acid on Prevention Particle Wears-Induced Implant Loosening by Promoting Periprosthetic Bone Architecture and Strength in an Ovariectomized Rat Model

Implant-generated particle wears are considered as the major cause for the induction of implant loosening, which is more susceptible to patients with osteoporosis. Monotherapy with parathyroid hormone (PTH) or zoledronate acid (ZOL) has been proven efficient for preventing early-stage periprosthetic osteolysis, while the combination therapy with PTH and ZOL has exerted beneficial effects on the treatment of posterior lumbar vertebral fusion and disuse osteopenia. However, PTH and ZOL still have not been licensed for the treatment of implant loosening to date clinically. In this study, we have explored the effect of single or combined administration with PTH and ZOL on implant loosening in a rat model of osteoporosis. After 12 weeks of ovariectomized surgery, a femoral particle-induced periprosthetic osteolysis model was established. Vehicle, PTH (5 days per week), ZOL (100 mg/kg per week), or combination therapy was utilized for another 6 weeks before sacrifice, followed by micro-CT, histology, mechanical testing, and bone turnover examination. PTH monotherapy or combined PTH with ZOL exerted a protective effect on maintaining implant stability by elevating periprosthetic bone mass and inhibiting pseudomembrane formation. Moreover, an additive effect was observed when combining PTH with ZOL, resulting in better fixation strength, higher periprosthetic bone mass, and less pseudomembrane than PTH monotherapy. Taken together, our results suggested that a combination therapy of PTH and ZOL might be a promising approach for the intervention of early-stage implant loosening in patients with osteoporosis.

Team Approach: Preoperative Management of Metabolic Conditions in Total Joint Replacement

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Total joint arthroplasties (TJAs) of the knee and hip have been considered 2 of the most successful surgical procedures performed to date.

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Frailty is defined as increased vulnerability to adverse outcomes with physiologic stress.

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Preoperative optimization of frailty and metabolic bone conditions, including osteoporosis, vitamin D deficiency, and diabetes, through a multidisciplinary approach can help improve outcomes and minimize costs after TJA.

Risk factors for a radiolucent line around the acetabular component with an interface bioactive bone cement technique after primary cemented total hip arthroplasty

Aims

The main aims were to identify risk factors predictive of a radiolucent line (RLL) around the acetabular component with an interface bioactive bone cement (IBBC) technique in the first year after THA, and evaluate whether these risk factors influence the development of RLLs at five and ten years after THA.

Methods

A retrospective review was undertaken of 980 primary cemented THAs in 876 patients using cemented acetabular components with the IBBC technique. The outcome variable was any RLLs that could be observed around the acetabular component at the first year after THA. Univariate analyses with univariate logistic regression and multivariate analyses with exact logistic regression were performed to identify risk factors for any RLLs based on radiological classification of hip osteoarthritis.

Results

RLLs were detected in 27.2% of patients one year postoperatively. In multivariate regression analysis controlling for confounders, atrophic osteoarthritis (odds ratio (OR) 2.17 (95% confidence interval (CI), 1.04 to 4.49); p = 0.038) and 26 mm (OR 3.23 (95% CI 1.85 to 5.66); p < 0.001) or 28 mm head diameter (OR 3.64 (95% CI 2.07 to 6.41); p < 0.001) had a significantly greater risk for any RLLs one year after surgery. Structural bone graft (OR 0.19 (95% CI 0.13 to 0.29) p < 0.001) and location of the hip centre within the true acetabular region (OR 0.15 (95% CI 0.09 to 0.24); p < 0.001) were significantly less prognostic. Improvement of the cement-bone interface including complete disappearance and poorly defined RLLs was identified in 15.1% of patients. Kaplan-Meier survival analysis for the acetabular component at ten years with revision of the acetabular component for aseptic loosening as the end point was 100.0% with a RLL and 99.1% without a RLL (95% CI 97.9 to 100). With revision of the acetabular component for any reason as the end point, the survival rate was 99.2% with a RLL (95% CI 97.6 to 100) and 96.5% without a RLL (95% CI 93.4 to 99.7).

Conclusion

This study demonstrates that acetabular bone quality, head diameter, structural bone graft, and hip centre position may influence the presence of the any RLL.

Cite this article: Bone Joint Open 2021;2(5):278–292.

Primary total hip arthroplasty using a short bone-conserving stem in young adult osteoporotic patients with Dorr type C femoral bone

BACKGROUND

Dorr type C femoral bone exhibits a wide, stovepipe-shaped femoral canal, and thin cortices in the proximal femur. Dorr C bone combined with severe osteoporosis is an important challenge in primary hip arthroplasty. In this study, we assessed the effects of short metaphyseal fitting cementless stems on preformatted primary total hip arthroplasties in young adult osteoporotic patients with this femoral presentation.

METHODS

A total of 42 hip arthroplasties were performed in 35 young patients (range 20 to 36 years) using a short Tri-lock bone preservation metaphyseal-fitting cementless femoral component between 2012 and 2017. The mean age at surgery of the 27 male (33 hips) and 8 female (9 hips) patients was 27.5 years (range 20.3 to 35.8 years). The mean body mass index (BMI) was 20.2 kg/m² (range, 16.8-23.2 kg/m²). According to Dorr's criteria, all 42 femora were classified as type C bone and all femurs suffered from severe osteoporosis (Singh index ≤ 3).

RESULTS

The mean follow-up period was 5.5 years (range 3.0 to 8.0 years). The clinical and functional results improved for the Harris hip score, WOMAC, and UCLA activity scores. The Harris Hip score improved from 48.0 ± 8.0 (range 38.0 to 61.0) preoperatively to 87.0 ± 9.0 (range 77.0 to 92.0) at 12 months after surgery and 91.0 ± 8.0 (range 85.0 to 98.0) at final follow-up. The preoperative UCLA activity score was 3.0 ± 0.5 points (range, 1.0-4.0 points), which significantly improved to 7.5 ± 0.7 points (range 6.0 to 8.0 points) at the final follow-up. No patient exhibited thigh pain at the final follow-up. The mean stem-to-canal fill percentages were 97% ± 2.1% (anteroposterior view at midstem). For stem alignment, 40 hips (95.2%) of the femoral stem were positioned neutrally to 3° of varus with reference to the femoral shaft axis. The remaining two were positioned at 4° varus to 4° valgus. Radiographic evaluation showed good osteointegration of the implants in follow-up.

CONCLUSIONS

Based on the tapered-wedge design and proximal porous coating, the shortened tapered conventional stem can achieve reliable stability through neck filling and metaphyseal fixation, which does not depend on the isthmus hoop stress. This stem was suitable in severe osteoporotic patients with type C bones in young adults who presented with a correspondingly straightened femoral canal with a wide isthmus and thin cortex.

Biomechanical Analysis to Probe Role of Bone Condition and Subject Weight in Stiffness Customization of Femoral Stem for Improved Periprosthetic Biomechanical Response

Stress shielding due to difference in stiffness of bone and implant material is one among the foremost causes of loosening and failure of load-bearing implants. Thus far, femoral geometry has been given priority for the customization of total hip joint replacement (THR) implant design. This study, for the first time, demonstrates the key role of bone condition and subject-weight on the customization of stiffness and design of the femoral stem. In particular, internal hollowness was incorporated to reduce the implant stiffness and such designed structure has been customized based on subject parameters, including bone condition and bodyweight. The primary aim was to tailor these parameters to achieve close to natural strain distribution at periprosthetic bone and to reduce interfacial bone loss over time. The maintenance of interfacial bone density over time has been studied here through analysis of bone remodeling (BR). For normal bodyweight, the highest hollowness exhibited clinically relevant biomechanical response, for all bone conditions. However, for heavier subjects, consideration of bone quality was found to be essential as higher hollowness induced bone failure in weaker bones and implant failure in stronger bones. Moreover, for stronger bone, thinner medial wall was found to reduce bone resorption over time on the proximo-lateral zone of stress shielding, while lateral thinning was found advantageous for weaker bones. The findings of this study are likely to facilitate designing of femoral stems for achieving better physiological outcomes and enhancement of the quality of life of patients undergoing THR surgery.

Total hip arthroplasty in patients with osteoporosis

There is a high prevalence of osteoporosis in patients undergoing total hip arthroplasty. There are several clinically relevant questions related to the management of such cases: the effect of ageing; the initial osseointegration of implants, especially when cementless THA is used; the effect of medical osteoporosis treatment on bone-implant interface; the incidence of intraoperative and late periprosthetic fractures, and the long-term survival of both cemented and cementless total hip arthroplasty performed for proximal femoral fractures and hip osteoarthritis. A critical review of the literature is presented in an attempt to draw practical conclusions.

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.

Computed tomography porosity and spherical indentation for determining cortical bone millimetre-scale mechanical properties

The cortex of the femoral neck is a key structural element of the human body, yet there is not a reliable metric for predicting the mechanical properties of the bone in this critical region. This study explored the use of a range of non-destructive metrics to measure femoral neck cortical bone stiffness at the millimetre length scale. A range of testing methods and imaging techniques were assessed for their ability to measure or predict the mechanical properties of cortical bone samples obtained from the femoral neck of hip replacement patients. Techniques that can potentially be applied in vivo to measure bone stiffness, including computed tomography (CT), bulk wave ultrasound (BWUS) and indentation, were compared against in vitro techniques, including compression testing, density measurements and resonant ultrasound spectroscopy. Porosity, as measured by micro-CT, correlated with femoral neck cortical bone's elastic modulus and ultimate compressive strength at the millimetre length scale. Large-tip spherical indentation also correlated with bone mechanical properties at this length scale but to a lesser extent. As the elastic mechanical properties of cortical bone correlated with porosity, we would recommend further development of technologies that can safely measure cortical porosity in vivo.

Efficacy of risedronate in improving bone mineral density in patients undergoing total hip arthroplasty: A meta-analysis of randomized controlled trials

BACKGROUND

Risedronate is widely used in the therapy of osteoporosis and other metabolic bone diseases. This meta-analysis was aimed to assess whether administration risedronate could increase the bone mineral density (BMD) in patients undergoing primary total hip arthroplasty (THA).

METHODS

Electronic databases: PubMed, EMBASE, Web of Science, Cochrane Library, and Chinese Wanfang database were searched for all relevant studies. Inclusion criterion was that patients prepared for THA and use risedronate as intervention group and placebo as control group. BMD change in Gruen zone 1 and 7 were primary outcomes. Meta-analysis was performed using Stata 12.0 software.

RESULTS

Six RCTs were finally included in this meta-analysis. Compared with control group, risedronate has a beneficial role in increasing BMD in Gruzen 1, 2 6, and 7 at 3 months (P < .05). Oral risedronate has a beneficial role in preservation of BMD in all of the Gruen zones at 6 and 12 months (P < .05). Moreover, oral risedronate could significantly increase the Harris hip scores and bone alkaline phosphatase than control group (P < .05).

CONCLUSION

Oral risedronate has an effect on the preservation of periprosthetic BMD in proximal regions (Gruen zone 1, 2, 3, and 7) at 3 months and all of the regions at 6 and 12 months after THA.

Effects of bisphosphonates in preventing periprosthetic bone loss following total hip arthroplasty: a systematic review and meta-analysis

BACKGROUND

Periprosthetic bone loss following total hip arthroplasty (THA) was a well-known phenomenon. This systematic review was to assess the effectiveness of bisphosphonates (BPs) for decreasing periprosthetic bone resorption.

METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were searched up to March 2018. Randomized controlled trials compared the effects between administrating BPs and placebo or no medication were eligible; the target participants were patients who underwent THA. Mean differences (MD) and 95% confidence interval (95% CI) were calculated by using the random-effects models. Statistical analyses were performed by RevMan 5.3 software.

RESULTS

Fourteen trials involving 620 patients underwent THA were retrieved. BPs significantly prevented the loss of periprosthetic bone mineral density at 1 year (MD, 0.06 [95% CI, 0.03 to 0.08], p < 0.001), between 2 and 4 years (MD, 0.04 [95% CI, 0.01 to 0.07], p = 0.02), and more than 5 years after THA (MD, 0.08 [95% CI, 0.06 to 0.11], p < 0.001). Both serum bone alkaline phosphatase (MD, - 7.28 [95% CI, - 9.81 to - 4.75], p < 0.001) and urinary N-telopeptide of type I collagen (MD, - 24.37 [95% CI, - 36.37 to - 12.37], p < 0.001) in BP group were significantly lower. Subgroup analyses showed that the third-generation BPs were more effective in decreasing periprosthetic bone loss than the first and second generation within 1 year after THA (p = 0.001).

CONCLUSION

BPs were beneficial to decreasing periprosthetic bone loss. The third-generation BPs showed significantly efficacy for patients in short-term observation.

Five-year experience of cementless Oxford unicompartmental knee replacement

PURPOSE

Cementless unicompartmental knee replacement (UKR) was introduced to address some of the problems that can occur following cemented UKR. The aim of this study was to report the 5-year experience of the first 512 medial cementless Oxford UKR implanted by two surgeons for the recommended indications.

METHODS

The first consecutive 512 cementless Phase 3 Oxford UKRs implanted by two surgeons for the recommended indications between June 2004 and October 2013 were prospectively identified and followed up independently. All the procedures were carried out through a minimally invasive approach without eversion or dislocation of the patella. Patients were assessed clinically pre-operatively and at 1, 2, 5, 7 and 10 years after surgery with functional outcome scores and radiographs.

RESULTS

There were eight reoperations of which six were revisions giving a 5-year survival of 98 % (95 % CI 94-100 %). At a mean follow-up of 3.4 years (1.0-10.2), the mean OKS was 43 (SD 7), AKSS (objective) was 81 (SD 13), and AKSS (functional) was 86 (SD 17). The first 120 cases had a minimum follow-up of 5 years (mean 5.9; range 5-10.2). In these patients, the mean OKS was 41 (SD 8), AKSS (objective) was 81 (SD 14), and AKSS (functional) was 82 (SD 18). There were no femoral radiolucencies and no complete tibial radiolucencies. 11 % of tibial components had partial radiolucent lines; the remaining 89 % had no radiolucencies.

CONCLUSION

The clinical results are as good as or better than those previously reported for cemented fixation. The radiographic results are better with secure bony attachment to the implants in every case.

LEVEL OF EVIDENCE

IV.

Smoking Increases the Rate of Reoperation for Infection within 90 Days After Primary Total Joint Arthroplasty

BACKGROUND

The relationship between smoking and complications after total joint arthroplasty is unclear. Prior studies have been limited by relatively small sample sizes or investigation of select cohorts. The purpose of this study was to investigate the association between smoking and readmission and/or reoperation within 90 days of total joint arthroplasty in a large, non-select cohort of patients.

METHODS

Using our institutional database, we retrospectively identified patients who underwent primary total joint arthroplasty between 2000 and 2014. Patients were stratified into 1 of 3 groups: current smokers, former smokers, and nonsmokers. The association between smoking status and subsequent readmission and/or reoperation within 90 days was investigated using multivariate regression analysis.

RESULTS

We retrospectively identified 15,264 patients (6,749 male and 8,515 female) who underwent 17,394 total joint arthroplasties during the study period. Of these patients, 1,371 (9.0%) were current smokers, 5,195 (34.0%) were former smokers, and 8,698 (57.0%) were nonsmokers. Former smokers reported a median of 22.2 years (range, 0.2 to 60 years) of abstinence prior to the surgical procedure. Current smokers were significantly younger (p < 0.001) at a mean age (and standard deviation) of 57.7 ± 10.3 years than nonsmokers at 63.2 ± 11.8 years. Current smokers were significantly more likely than nonsmokers to undergo reoperation for infection (odds ratio [OR], 1.82 [95% confidence interval (CI), 1.03 to 3.23]; p = 0.04), and former smokers were at no increased risk (OR, 1.11 [95% CI, 0.73 to 1.69]; p = 0.61). Packs per decade were independently associated with an increased risk of 90-day nonoperative readmission regardless of smoking status (OR, 1.12 [95% CI, 1.03 to 1.20]). Lastly, neither smoking status nor packs per decade were associated with aseptic or total reoperations.

CONCLUSIONS

This study, after controlling for confounding factors, demonstrated not only that current smokers have a significantly increased risk of reoperation for infection within 90 days of a surgical procedure compared with nonsmokers, but also that the amount that one has smoked, regardless of current smoking status, significantly contributed to increased risk of nonoperative readmission.

LEVEL OF EVIDENCE

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

Daily activity and initial bone mineral density are associated with periprosthetic bone mineral density after total hip arthroplasty

OBJECTIVES

To evaluate periprosthetic bone mineral density (BMD) changes around a cementless short tapered-wedge stem and determine correlations between BMD changes and various clinical factors, including daily activity, after total hip arthroplasty (THA) with a tapered-wedge stem.

METHODS

65 patients underwent THA with a TriLock BPS stem. At baseline and at 6, 12, and 24 months postoperatively the BMD of the 7 Gruen zones were evaluated using dual-energy x-ray absorptiometry. Correlations were determined between BMD changes and clinical factors, including the Harris Hip Score, body mass index, University of California at Los Angeles (UCLA) activity rating score, age at surgery, and initial spine BMD. Radiographic parameters, including the proximal femoral geometry (Dorr Classification), canal filling ratio, canal flare index, and calcar-to-canal ratio were also assessed.

RESULTS

Minimal BMD changes were noted in the distal femur. However, significant BMD loss was noted in zone 7 at each time point. BMD loss was also noted in zone 1 at 6 and 12 months postoperatively, but BMD recovered after 18 months. Significant positive correlations were noted between BMD changes and the UCLA activity score in zones 1, 6, and 7. Additionally, negative correlations were noted between BMD changes and the preoperative lumbar BMD in zones 2 and 3. No correlations were noted between BMD changes and the radiographic parameters. Periprosthetic BMD was was virtually unchanged in the proximal femur, especially Gruen zone 1.

CONCLUSIONS

Daily activity may reflect improvements in periprosthetic bone quality after THA; however, the use of this tapered-wedge stem is not recommended in patients with poor bone quality.

Effect of smoking on complications following primary shoulder arthroplasty

BACKGROUND

The purpose of this study was to examine the effect of smoking on the incidence of complications after primary anatomic total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA).

METHODS

All patients who underwent primary TSA or RSA at our institution between 2002 and 2011 and had a minimum 2-year follow-up were included. Smoking status was assessed at the time of surgery. Current smokers, former smokers, and nonsmokers were compared for periprosthetic infection, fractures (intraoperative and postoperative), and loosening after surgery.

RESULTS

The cohort included 1834 shoulders in 1614 patients (814 in smokers and 1020 in nonsmokers). Complications occurred in 73 patients (75 shoulders; 44 in smokers and 31 in nonsmokers). There were 20 periprosthetic infections (16 in smokers and 4 in nonsmokers), 27 periprosthetic fractures (14 in smokers and 13 in nonsmokers), and 28 loosenings (14 in smokers and 14 in nonsmokers). Smokers had lower periprosthetic infection-free survival rates (95.3%-99.4% at 10 years; P = .001) and overall complication-free survival rates (78.4%-90.2%; P = .012) than nonsmokers. Multivariable analyses showed that both current and former smokers had significantly higher risk of periprosthetic infection in comparison with nonsmokers (hazard ratio [HR], 7.27 and 4.56, respectively). In addition, current smokers showed a higher risk of postoperative fractures than both former smokers (HR, 3.63) and nonsmokers (HR, 6.99).

CONCLUSIONS

This study demonstrates that smoking is a significant risk factor of complications after TSA and RSA. These findings emphasize the need for preoperative collaborative interventions, including smoking cessation programs.

Simple radiographic assessment of bone quality is associated with loss of surgical fixation in patients with proximal humeral fractures

AIM

This study aimed to determine if the ratio of cortical thickness to shaft diameter of the humerus, as measured on a simple anterior-posterior shoulder radiograph, is associated with surgical fixation failure.

PATIENTS AND METHODS

64 consecutive fractures in 63 patients (mean age 66.1 years, range 35-90) operated with surgical fixation between March 2011 and July 2014 using PERI-LOC locking plate and screws (Smith and Nephew, UK) were identified. Predictors of bone quality were measured from preoperative radiographs, including ratio of the medial cortex to shaft diameter (medial cortical ratio, MCR). Loss of fixation (displacement, screw cut out, or change in neck-shaft angle >4 degrees) was determined on follow-up radiographs.

RESULTS

Loss of fixation occurred in 14 patients (21.9%) during the follow up. Patients were older in the failure group 72.8 vs. 64.2 years (p=0.007). The MCR was significantly lower in patients with failed fixation 0.170 vs 0.202, p=0.019. Loss of fixation is three times more likely in patients with a MCR <0.16 (41% vs. 14%, p=0.015). Increased fracture parts led to increased failure rate (p=0.0005).

CONCLUSION

Medial cortex ratio is significantly associated with loss of surgical fixation and may prove to be a useful adjunct for clinical decision making in patients with proximal humeral fractures.

Total hip replacement in osteoarthritis: the role of bone metabolism and its complications

Osteoarthritis is one of the most common joint disorder. For treatment of hip symptomatic osteoarthritis, when conservative medical therapy has failed, total hip arthroplasty (THA) is a successful orthopaedic procedures that reduces pain and improves function and quality of life. Incidence of osteoarthritis is constantly increasing with raising life expectancy. This aging process also has led to an increasing number of patients with osteoporosis who need hip replacement for osteoarthritis. Osteoporosis have 3 major potential complications in total hip arthroplasty: perioperative fracture, an increased risk of periprosthetic fracture, and late aseptic loosening. The purpose of the present study was to examine the effects of osteoporosis on total hip replacement procedure outcome and highlight the importance of adequate study of calcium-phosphorus metabolism in patient candidate for hip surgery, and the need to start a suitable therapy to recover the bone mass before surgery. Bone quality of the hip joint has become an important risk factor limiting the durability of THA.

Periprosthetic fractures around the femoral stem: overcoming challenges and avoiding pitfalls

Management of periprosthetic fractures around the femoral stem after total hip arthroplasty (THA) represents a significant challenge and optimal treatment remains controversial. The most common treatment paradigm involves treating fractures around a well-fixed stem with osteosynthesis, whereas fractures around a loose stem require revision arthroplasty and those with poor bone require augmentation with bone graft. Paradoxically, the literature reports a higher rate of failure for osteosynthesis around prostheses considered to be well-fixed. Such a high rate of poor outcomes may result not only from difficult fracture fixation and compromised biologic healing, but also from unrecognized peri-implant pathology. Therefore, proper preoperative and intraoperative evaluation is key, and a subset of patients may benefit from alternative management. We review the appropriate methods for evaluation and treatment of Vancouver type B fractures with particular emphasis on avoiding missteps that can lead to failure.

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.

What Host Factors Affect Aseptic Loosening After THA and TKA?

BACKGROUND

Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening.

QUESTIONS/PURPOSE

We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA.

METHODS

Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI≥30 kg/m2, and current or former tobacco use) and one factor in TKA (BMI≥30 kg/m2), which were placed in a forest plot.

RESULTS

For THA, male sex (OR, 1.39; 95% CI, 1.22-1.58; p=0.001) and high activity level (University of California Los Angeles [UCLA] activity score≥8 points; OR, 4.24; 95% CI, 2.46-7.31; p=0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73-1.40; p=0.96), and tobacco use (OR, 1.96; 95% CI, 0.43-8.97; p=0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI≥30 kg/m2) was not associated with aseptic loosening with the numbers available (OR, 2.28; 95% CI, 0.60-8.62; p=0.22).

CONCLUSIONS

Patients undergoing a lower-extremity total joint arthroplasty who engage in impact sports should be counseled regarding their potential increased risk of aseptic loosening; however, given the weak evidence available, we believe that higher-level studies are necessary to clearly define the risk factors, particularly with newer-generation constructs.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Subjective results of joint lavage and viscosupplementation in hemophilic arthropathy

OBJECTIVE

To assess whether joint lavage, viscosupplementation and triamcinolone improve joint pain, function and quality of life in patients with severe hemophilic arthropathy.

METHODS

Fourteen patients with knee and/or ankle hemophilic arthritis with and without involvement of other joints underwent joint lavage and subsequent injection of hylan G-F20 and triamcinolone in all affected joints. The patients answered algo-functional questionnaires (Lequesne and WOMAC), visual analog scale for pain (VAS) and SF-36 preoperatively, and at one, three, six and twelve months postoperatively.

RESULTS

Sixteen knees, 15 ankles, 8 elbows and one shoulder were treated in 14 patients. Six patients had musculoskeletal bleeding [ankle (1), leg muscle (2) and knees (4)] at 3 months affecting the results. Pain did not improve significantly. Function improved (WOMAC p=0.02 and Lequesne p=0.01). The physical component of SF-36 improved at all time points except at 3 months, with best results at one-year follow-up (baseline = 33.4; 1 month = 39.6; 3 months= 37.6; 6 months 39.6 and 1 year = 44.6; p < 0.001).

CONCLUSION

Joint lavage followed by injection of triamcinolone and hylan G-F20 improves function and quality of life progressively up to a year, even in severe hemophilic arthropathy. Level of Evidence IV, Case Series.

No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty

BACKGROUND

The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris.

PATIENTS AND METHODS

49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28-68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density.

RESULTS

At 1-2 years, mean total translation (TT) was 0.04 mm (95% CI: -0.07 to 0.14; p = 0.5) for the stems; at 2-5 years, mean TT was 0.13 mm (95% CI: -0.25 to -0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1-2 and 2-5 years. At 2-5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < -1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)).

INTERPRETATION

Most cups and stems were well-fixed at 1-5 years. However, at 2-5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the fixation of hip components in large-head MoM articulations at medium-term follow-up.

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.

Pharmacologic augmentation of implant fixation in osteopenic bone

Osteoporosis presents a challenge for successful implant fixation due to an impaired healing response. Preclinical studies have consistently reported reduced osseointegration capability in trabecular bone. Although clinical studies of implant success in dentistry have not found a negative effect due to osteoporosis, low bone mass is a significant risk factor for implant migration in orthopedics. Pharmacologic treatment options that limit bone resorption or upregulate formation have been studied preclinically. While, both treatment options improve implant fixation, direct comparisons to-date have found anti-catabolic more effective than anabolic treatments for establishing implant fixation, but combination approaches are better than either treatment alone. Clinically, anti-catabolic treatments, particularly bisphosphonates have been shown to increase the longevity of implants, while limited clinical evidence on the effects of anabolic treatment exists. Preclinical experiments are needed to determine the effects of osteoporosis and subsequent treatment on the long-term maintenance of fixation and recovery after bone loss.

[Aspects of interest on vitamin D for the traumatologist and orthopaedic surgeon]

Vitamin D deficiency or insufficiency is a clinical problem particularly prevalent in elderly patients with low-energy fractures, particularly hip fractures, but has also been associated with stress fractures and high energy fractures. There is much evidence that supports the need to maintain adequate levels of vitamin D in the blood in order to; reduce the number of fragility fractures, furthering the consolidation of these, improve neuromuscular function of patients, prevent falls, prevent surgical infections, or improve the length of arthroplasties. However, it is rare for the orthopaedic surgeon to request the values of vitamin D in these patients and give the appropriate treatment It is recommended to maintain levels higher than 30-40ng/ml (75-100nmol/l) and increase vitamin D intake, in almost all cases, from 800 to 1,000IU/day to achieve these levels.

Review of periprosthetic osteolysis in total joint arthroplasty: an emphasis on host factors and future directions

Periprosthetic osteolysis is one of the leading causes of total joint revision procedures. If allowed to progress in the absence of radiographic diagnosis and/or proper medical treatment, osteolysis may result in aseptic loosening yielding failure of the implant and the need for complex revision arthroplasty. The purpose of this review was to assess the current understanding of periprosthetic osteolysis with an emphasis on host factors and future directions. A PubMed search was conducted using the following key words; osteolysis, periprosthetic osteolysis, osteolysis imaging. Pertinent articles, as it pertained to the outline of the review, were selected. Periprosthetic osteolysis stems from numerous risk factors. Osteolysis host characteristic risk factors include gender, body weight, and genetics. Current implant designs have reduced the incidence of this disease; however no current design has been able to replicate the in vivo characteristics and therefore development of wear particles continues to be seen. Advanced methods of imaging diagnosis are on the rise, however early imaging diagnosis is currently ineffective. Pharmacologic intervention appears to be a logical avenue for medical intervention, but no approved drug therapy to prevent or inhibit periprosthetic osteolysis is currently available. Although the rate of periprosthetic osteolysis seems to be decreasing with advances in implant design and increased knowledge of the biological process of wear particle induced osteolysis, the rapid increase in the total number of total joint arthroplasties over the next two decades means that better ways of detecting and treating periprosthetic osteolysis are greatly needed.

[Periprosthetic fractures. An interdisciplinary challenge]

Demographic changes and rising numbers of implanted prostheses accompanied by increasing demands on mobility and activities of the elderly will lead to an increasing number of periprosthetic fractures in the future. Poor bone quality, geriatric comorbidities and multiple prostheses result in an increased risk for this type of fracture in the old patient. Management of these patients is challenging and demanding and needs an interdisciplinary approach. The present work describes the different aspects of periprosthetic fractures in the geriatric patient with regard to epidemiology, risk factors, prevention and treatment options.

Surgical treatment options in patients with impaired bone quality

BACKGROUND

Bone quality should play an important role in decision-making for orthopaedic treatment options, implant selection, and affect ultimate surgical outcomes. The development of decision-making tools, currently typified by clinical guidelines, is highly dependent on the precise definition of the term(s) and the appropriate design of basic and clinical studies. This review was performed to determine the extent to which the issue of bone quality has been subjected to this type of process.

QUESTIONS/PURPOSES

We address the following issues: (1) current methods of clinically assessing bone quality; (2) emerging technologies; (3) how bone quality connects with surgical decision-making and the ultimate surgical outcome; and (4) gaps in knowledge that need to be closed to better characterize bone quality for more relevance to clinical decision-making.

METHODS

PubMed was used to identify selected papers relevant to our discussion. Additional sources were found using the references cited by identified papers.

RESULTS

Bone mineral density remains the most commonly validated clinical reference; however, it has had limited specificity for surgical decision-making. Other structural and geometric measures have not yet received enough study to provide definitive clinical applicability. A major gap remains between the basic research agenda for understanding bone quality and the transfer of these concepts to evidence-based practice.

CONCLUSIONS

Basic bone quality needs better definition through the systematic study of emerging technologies that offer a more precise clinical characterization of bone. Collaboration between basic scientists and clinicians needs to improve to facilitate the development of key questions for sound clinical studies.

Smoking and outcomes after knee and hip arthroplasty: a systematic review

OBJECTIVE

Studies have suggested higher rates of perioperative and postoperative complications in smokers compared to nonsmokers. The objective of this systematic review was to assess the association of smoking and postoperative outcomes following total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHODS

A search of 6 databases (The Cochrane Library, Scopus, Proquest Dissertation abstracts, CINAHL, Ovid Medline, and Embase) was performed by a Cochrane librarian. All titles and abstracts were screened by 2 independent reviewers with expertise in performing systematic reviews. Studies were included if they were fully published reports that included smoking and any perioperative or postoperative clinical outcome in patients with TKA or THA.

RESULTS

A total of 21 studies were included for the review, of which 6 provided multivariable-adjusted analyses, 14 univariate analyses, and one statistical modeling. For most outcomes, results from 1-2 studies could be pooled. Current smokers were significantly more likely to have any postoperative complication (risk ratio 1.24, 95% CI 1.01 to 1.54) and death (risk ratio 1.63, 95% CI 1.06 to 2.51) compared to nonsmokers. Former smokers were significantly more likely to have any post-operative complication (risk ratio 1.32, 95% CI 1.05 to 1.66) and death (risk ratio 1.69, 95% CI 1.08 to 2.64) compared to nonsmokers.

CONCLUSION

This systematic review found that smoking is associated with significantly higher risk of postoperative complication and mortality following TKA or THA. Studies examining longterm consequences of smoking on implant survival and complications are needed. Smoking cessation may improve outcomes after THA or TKA.

Use of morphometry to quantify osteolysis after total hip arthroplasty

BACKGROUND

Progressive osteolysis threatens the longevity of hip arthroplasties and radiographic review is recommended. Measurement of osteolytic lesions in a clinical setting has not been achieved easily in the past. Other radiologic investigations provide accurate information but cost and risk to the patient prohibit their use in routine review.

QUESTIONS/PURPOSES

We developed a simple, reliable tool to be used in hip arthroplasty review to quantify osteolytic changes seen on plain film radiographs.

METHODS

A morphometric grid was developed and tested on simulated and actual osteolytic lesions. Four health professionals measured lesions on each of two occasions. Intraclass correlation coefficients (ICC) for interobserver and intraobserver reliabilities were calculated and Bland-Altman plots were constructed for graphic analysis.

RESULTS

The ICCs for interobserver reliability on the simulated and actual osteolytic lesions were in the range 0.90 to 0.96. The values for intraobserver (test-retest) reliability were 0.97 to 0.98. The Bland-Altman plots confirmed agreement and in each case, proximity of the mean to zero indicated no significant bias.

CONCLUSIONS

The data show a morphometric grid is reliable for measuring osteolytic changes after hip arthroplasty.

CLINICAL RELEVANCE

This tool has potential to improve monitoring processes for hip arthroplasty and to be useful in future research studies. Additional work is needed to test for validity and clinical importance of the measurements obtained.

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

The triple-taper cemented femoral stem was developed to promote proximal femoral and calcar loading to minimize periprosthetic bone loss and aseptic loosening. Periprosthetic changes in bone mineral density in Gruen zones 1 to 7 were analyzed in 103 patients over a 2-year period using dual x-ray absorptiometry. There was a statistically significant decrease in bone mineral density in all Gruen zones, but was most marked in zones 1 and 7. Periprosthetic bone density was reduced significantly in the first 3 to 9 months, after which recovery of bone density occurred. Greater calcar bone loss was seen in women, patients with a low preoperative bone density, and patients with poor postoperative mobility. Age at surgery did not effect calcar bone loss.

Alendronate reduces periprosthetic bone loss after uncemented primary total hip arthroplasty - a 5-year follow-up of 16 patients

BACKGROUND AND AIMS

Periprosthetic bone loss, especially in the proximal part of the femur, is common after cemented and uncemented total hip arthroplasty (THA). Short-term studies suggest that bisphosponates can minimize this bone loss related to stress-shielding phenomenon. The aim of the present randomized study was to investigate whether the positive effect of a 6 months alendronate treatment postoperatively still exists at five-year follow up.

MATERIALS AND METHODS

Sixteen uncemented primary THA patients were randomized to receive either 10mg alendronate + 500 mg calcium (n = 7) or 500 mg calcium only (n = 9) daily for 6 months postoperatively. Periprosthetic bone mineral density (BMD) was measured with the dual X-ray absorptiometry (DXA) postoperatively and at 6, 12, 24, 36 and 60 months follow-up.

RESULTS

At the 5-year follow up, the calcium group showed mean BMD decreases of 23.1% (SD 14.6) in the proximal part of the femur (prROI) and 9.6% (SD 14.9) in total femoral regions of interest (totROI). In the alendronate group the corresponding BMD decreases were 13.6% (SD 19.0) and 3.9% (SD 7.6) respectively. The positive effect of alendronate was already demonstrated during the first six months postoperatively. Subsequently the bone loss was equal in both groups, and the 5-year BMD changes were not significantly different between the groups.

CONCLUSIONS

Alendronate seems to decrease early periprosthetic bone loss after arthroplasty but this pilot study could not provide enough evidence that the positive effect noted in the early postoperative period is still maintained 5 years after the operation.

Female patients with low systemic BMD are prone to bone loss in Gruen zone 7 after cementless total hip arthroplasty

BACKGROUND AND PURPOSE

Factors that lead to periprosthetic bone loss following total hip arthroplasty (THA) may not only depend on biomechanical implant-related factors, but also on various patient-related factors. We investigated the association between early changes in periprosthetic bone mineral density (BMD) and patient-related factors.

PATIENTS AND METHODS

39 female patients underwent cementless THA (ABG II) with ceramic-ceramic bearing surfaces. Periprosthetic BMD in the proximal femur was determined with DXA after surgery and at 3, 6, 12, and 24 months. 27 patient-related factors were analyzed for their value in prediction of periprosthetic bone loss.

RESULTS

Total periprosthetic BMD was temporarily reduced by 3.7% at 3 months (p < 0.001), by 3.8% at 6 months (p < 0.01), and by 2.6% at 12 months (p < 0.01), but recovered thereafter up to 24 months. Preoperative systemic osteopenia and osteoporosis, but not the local BMD of the operated hip, was predictive of bone loss in Gruen zone 7 (p = 0.04), which was the only region with a statistically significant decrease in BMD (23%, p < 0.001) at 24 months. Preoperative serum markers of bone turnover predicted the early temporary changes of periprosthetic BMD. The other patient-related factors failed to show any association with the periprosthetic BMD changes.

INTERPRETATION

Female patients with low systemic BMD show greater bone loss in Gruen zone 7 after cementless THA than patients with normal BMD. Systemic DXA screening for osteoporosis in postmenopausal patients before THA could be used to identify patients in need of prophylactic anti-resorptive therapy.

Early catastrophic failure of Birmingham acetabular dysplasia cup in revision arthroplasty: a case report

Introduction

Revision acetabulum arthroplasty is one of the common procedures, which has been on the rise recently. Many implants are available in the market with variable results. Aseptic loosening is the most common indication for revision acetabulum arthroplasty. Birmingham dysplasia cup has been used occasionally in these complex procedures. We know that these implants have provided good results in resurfacing dysplastic hips with bone loss. Literature review failed to answer whether these implants were as effective in revision acetabulum arthroplasty.

Case presentation

We herby, present a case of revision acetabulum arthroplasty performed with Birmingham dysplasia acetabular cup, which unfortunately failed within a period of eight months. Surgical technique appeared to be adequate. On further analysis, significant differences were identified between dysplastic hips with bone loss and revision hips with bone loss.

Conclusion

Therefore results obtained with dysplasia cups in resurfacing dysplastic hips does not seem to be applicable to revision hip arthroplasty. Hence these cups should be restricted to primary arthroplasty.