In vitro analysis of periprosthetic strains following total knee arthroplasty

Clinical case studies have disclosed certain risk factors associated with periprosthetic fracture in elderly patients. How the mechanical strength of the distal femur is changed by total knee arthroplasty (TKA) has not been elucidated. Using elderly cadaveric femora, this study evaluated both periprosthetic strains and associated fracture patterns arising from an in vitro simulation of a fall onto the distal femur. The data showed a significant increase in anterior and posterior mechanical strain following TKA. Neither stemless nor stemmed versions of two cemented Howmedica prostheses (Rutherford, NJ) reduced distal femur strains to baseline values. However, neither produced a disproportionate frequency of periprosthetic fractures. Although not formally evaluated herein, bone geometry/density may contribute more profoundly to the occurrence of periprosthetic fracture than the implants tested.     

One year after proximal or distal periprosthetic fracture of the femur -two conditions with divergent outcomes?

IntroductionArthroplasty of the hip and knee is 1 of the 20 most frequent operations in Germany. Periprosthetic fracture is one of the most feared complications following primary or revision arthroplasty. Present publication aims to analyse differences between patients with periprosthetic fracture around total knee arthroplasty (PFTKA) and patients with periprosthetic fracture around total hip arthroplasty (PFTHA) concerning demographics, clinical course, complications and return to pre-fracture mobility.MethodsProspective single-centre observation study of periprosthetic femoral fractures with stable implants. Present subgroup analysis includes patients with PFTKA and PFTHA. All patients were treated with polyaxial angular stable plates using two standardized techniques: a minimally invasive percutaneous distal insertion technique and a mini-open technique. Data collection included implant- and operation-related information as well as demographics, clinical course, complications and return to pre-fracture mobility. Data were collected during a 12-month follow-up.ResultsWe were able to analyse the data of 73 patients. The PFTKA group had 37 patients with a mean age of 76 ± 10 years; 88% were female. After 1 year, 3 patients in this cohort had died; 68% of survivors had reached their pre-fracture mobility; 22% had undergone operative revisions for various reasons. The PFTHA cohort included 36 patients with a mean age of 80 ± 13 years, 72% were female. After 1 year, 9 patients had died in this cohort, 42% of survivors had reached their pre-fracture mobility. Non-operative complications occurred for 16% in the PFTKA group and 64% in the PFTHA group (p < 0.001). 11% had undergone operative revisions for various reasons, among them, two cases of nonunion but no primary infection.ConclusionOn average, compared to the PFTHA patients, PFTKA patients were younger, underwent significantly lower rates of non-operative complications, had a tendency towards lower mortality, and returned to pre-fracture mobility at higher rates, although they tended to have more revisions when compared to treatment for PFTHA. Overall, when periprosthetic fractures of the femur were treated using polyaxial locking plate osteosynthesis, patients showed very low rates of nonunion and no primary infection.     

膝关节假体周围骨折的治疗

目的研究膝关节假体周围骨折的治疗方法。方法14例假体周围骨折，其中股骨骨折8例，胫骨骨折6例。4例拉力螺钉固定，4例多道钢丝固定，1例更换为铰链膝，5例采用LPC钢板固定。结果所有患者获得随访，平均随访时间24．5个月（6～44个月）。术后6～12周所有患者骨折均愈合（平均8．5周）。随访期内无感染及松动发生，1例皮肤切口延迟愈合。术后HSS评分平均为84分。结论多数膝关节假体周围骨折的患者能够获得功能重建和无痛的关节，LCP钢板是假体稳定的股骨骨折较适合的治疗方法。     

大颗粒聚乙烯对人工关节假体周围组织影响的实验研究

目的　制作松动人工关节的动物模型 ,了解大颗粒聚乙烯对实验动物人工关节假体周围骨组织的影响 ,并初步探讨其作用机制。　方法　选用健康新西兰白兔 2 0只 ,雌雄各半 ,体重 2 .3～ 2 .7kg。从两侧膝关节向股骨置入钴 -铬 -钼棒 ,分别于术后 2、4、6、8及 10周向一侧膝关节腔内注射聚乙烯微粒 (直径 10 0 μm)悬液 1.5 ml(实验侧 ) ,向另一侧膝关节腔内注射生理盐水 1.5 ml(对照侧 )。术后第 10周摄双下肢 X线片 ,了解假体周围是否有骨溶解和假体松动。术后第 12周处死动物。取 13只兔检查聚乙烯颗粒在关节囊分布情况 ,假体有否松动 ,周围有无新骨及界膜形成 ;取5只兔双侧股骨、膝关节囊作组织学检查 (实验过程中有 2只动物死亡 )。　结果　 1肉眼观察 :实验侧有 4侧金属假体被新生骨组织覆盖 ,9侧被纤维膜覆盖 ;对照侧有 11侧金属假体被新生骨组织覆盖 ,2侧被纤维膜覆盖 ,差异有统计学意义(P<0 .0 5 )。2 X线片观察 :假体位于股骨髓腔远端 ,其周围未见明显新生骨组织和骨溶解征像。3组织学观察 :实验侧关节囊见大量异物颗粒被成纤维细胞和多核巨细胞包绕 ,假体近端髓腔周围见成纤维细胞和纤维组织或新生骨组织形成 ,未见异物颗粒和多核巨细胞 ,靠近关节面部分见异物颗粒被成纤维细胞和多核巨细胞包绕     

Monolithic Dual Mobility Cup Total Hip Arthroplasty Has High Complication Rates With Surgical Fixation in Elderly With Femur Neck Fracture

BackgroundThis study is prospectively conducted to evaluate surgical complications of monolithic dual mobility cup total hip arthroplasty (THA) in elderly patients with fractured neck of the femur.MethodsNinety-seven patients (97 hips) with displaced femoral neck fracture who gave informed consent for participation were prospectively enrolled. Their mean age was 76.6 years (range, 60-95 years), and the mean bone mineral density T-score of neck of the femur was −2.8 (range, −1.2 to −5.5). All patients underwent THA with monolithic dual mobility cup, and computed tomography scans were obtained to evaluate radiographic parameters including anteversion, inclination, and loosening of acetabular cups, and periprosthetic acetabular fractures.ResultsWith regard to cup orientation, mean inclination angle was 40.2° (range, 23.5°-63°) and mean anteversion was 32.6° (range, 7°-66.2°). The proportion of surgical outliers was 10.3% (10/97) in inclination and 35.1% (34/97) in anteversion. Early cup loosening within 2 weeks was detected in 2 hips. Periprosthetic acetabular fractures were identified in 6 hips (6/97, 6.2%). Of the 6 fractures, 5 nondisplaced fractures were healed with conservative management, but 1 fracture with displacement eventually led to cup loosening and the patient underwent revision surgery. Reoperation rate of the monolithic dual mobility cup was 4.1% (4/97).ConclusionThe use of the monolithic dual mobility was associated with improper cup fixation and periprosthetic acetabular fractures in the elderly with poor bone stock, although the dual mobility cup lowered the risk of early dislocation after THA.     

钢板结合异体骨板对粉碎性Vancouver B1型假体周围股骨骨折的疗效观察

目的 :观察钢板结合异体骨板对严重粉碎性Vancouver B1型假体周围股骨骨折的疗效,评价其效果。方法:2006年1月至2013年1月采用钢板-钢丝系统结合异体骨板治疗严重粉碎性Vancouver B1型股骨假体周围骨折患者8例,男6例,女2例;年龄56~74岁,平均62.52岁。所有患者采用长的钢板、钢丝及长度合适的异体骨板。以Harris评分标准对患者手术前后髋关节功能进行评估,通过数字化X线摄片技术对假体稳定性、异体骨板愈合情况进行评估。结果:8例患者获得随访,时间24~60个月,平均45个月,所有患者骨折愈合,未出现感染、松动、骨折不愈合及畸形愈合。Harris评分由术前的(28.45±5.78)分提高至术后的(83.46±10.21)分。至随访结束,7例患者假体稳定,异体骨板愈合良好;另1例患者因假体松动行翻修术。结论:应用钢板-钢丝系统结合异体骨板对严重粉碎性Vancouver B1型假体周围股骨骨折进行手术操作简便,并发症少,术后髋关节功能恢复良好,可以提高骨的质量,增加骨量,为Ⅱ期可能的翻修提供有利条件。     

Survival of Primary Condylar-Constrained Total Knee Arthroplasty at a Minimum of 7 Years

The purpose of the present study is to retrospectively analyze clinical and radiographic outcomes in primary constrained condylar knee arthroplasty at a minimum follow-up of 7 years. Given the concern for early aseptic loosening in constrained implants, we focused on this outcome. Our cohort consists of 127 constrained condylar knees. The mean age of patients in the study was 68.3 years, with a mean follow-up of 110.7 months. The diagnosis was primary osteoarthritis in 92%. There were four periprosthetic distal femur fractures, with a rate of revision of 0.8%. No implants were revised for aseptic loosening. Kaplan–Meier survivorship analysis with removal of any component as the end point revealed that the 10-year rate of survival of the primary CCK was 97.6% (95% CI, 94%–100%).     

Radiographic and Clinical Outcomes of Modular Tapered Fluted Stems for Femoral Revision for Paprosky III and IV Femoral Defects or Vancouver B2 and B3 Femoral Fractures

BackgroundExtensive femoral bone loss poses a challenge in revision total hip arthroplasty (rTHA). Many techniques have been developed to address this problem including fully porous cylindrical stems, impaction bone grafting, and cementation of long stems, which have had varied success. Modular tapered fluted femoral stems (MTFS) show favorable results. We sought to determine the minimum 2-year radiographic and clinical performance of MTFS in rTHA in a population with extensive proximal femoral bone loss.MethodsOur clinical database was queried retrospectively for all patients who underwent rTHA with an MTFS. We included patients with Paprosky 3 and 4 femoral bone loss and patients with Vancouver B2 and B3 periprosthetic femur fractures. Patients without 2-year follow-up were invited to return to clinic for X-ray evaluation and to complete clinical questionnaires. We assessed distance of stem subsidence and presence of stem fixation on final X-ray. We recorded all-cause revision and survival of the stem at final follow-up.ResultsOne hundred twenty-nine patients were available for follow-up. Average follow-up time was 3.75 years. One hundred twenty-two stems (95%) remained in place at final follow-up. Median subsidence was 1.4 mm (range 0-21). All-cause revision rate was 16.3% (21 patients). Of the hips revised, 10 were for instability, 6 for infection, 1 for aseptic loosening, and 1 for periprosthetic femur fracture. Three were revised for other reasons. The stem was revised in 7 patients (5.4%), and the most common reason for stem revision was infection (5 patients). The other 2 stems were revised for aseptic loosening in a Paprosky 4 femur and periprosthetic femur fracture. Survival of tapered modular fluted stems with aseptic failure as an endpoint was 98.4%. The mean Hip disability and Osteoarthritis Outcome Score, Joint Replacement score at final follow-up was 73, and mean Veterans Rand 12 item health survey physical and mental scores were 32.8 and 52.2, respectively.ConclusionIn patients with Paprosky 3, 4 femoral defects or Vancouver type B2, B3 fractures, modular tapered fluted stems for femoral revision show excellent outcomes at minimum 2-year follow-up.     

Superior Survival of Fully Cemented Fixation Compared to Hybrid Fixation in a Single Design Rotating Hinge Knee Implant

BackgroundClinical observations revealed higher rates of aseptic loosening for hybrid fixated rotating hinge knee implants compared to fully cemented ones. We hypothesize that the use of a fully cemented fixation technique had a higher survival rate for aseptic loosening compared to a hybrid fixation technique in a rotating hinge knee implant.MethodsAll procedures of patients who were treated with the RT-PLUS rotating hinge knee implant (Smith & Nephew, Memphis, TN) between 2010 and 2018 were included. Primary outcome was revision for aseptic loosening. Kaplan-Meier survivorship and Cox proportional hazard regression analysis were performed to calculate survival rates and hazard ratios.ResultsA total of 275 hinge knee implants were placed in 269 patients (60 primary procedures, 215 revisions). Median follow-up was 7.3 ± 3.9 years. In total, 24 components (16 hybrid femur, 2 fully cemented femur, 6 hybrid tibia; all revision procedures) in 19 patients were revised for aseptic loosening. Kaplan-Meier survivorship analysis showed superior survival rates of fully cemented components (femur 97.1%; tibia 100%) compared to hybrid fixated components (femur 89.5%; tibia 95.9%) at the 10-year follow-up. Multivariate Cox hazard analysis showed a significantly higher risk of aseptic loosening for hybrid fixated components, a prior stemmed component and the femoral component.ConclusionFully cemented fixation showed superior survival rates for aseptic loosening compared to hybrid fixation in a single design rotating hinge knee implant. A prior stemmed component appears to be a risk factor for aseptic loosening and the femoral component seems to be more prone to loosening.     

Indications,Survivorship, and Clinical Outcomes of a Rotating Hinge Total Knee and Distal Femoral Arthroplasty System

BackgroundRotating hinge knee prostheses (with or without distal femoral replacement) are indicated in cases of unreconstructible bony or soft tissue compromise. Despite their versatility, these implants have demonstrated high rates of mechanical failure. We aimed to review clinical outcomes of a novel hinged knee arthroplasty system.MethodsWe reviewed all cases in a prospective database of hinged total knee arthroplasty (with and without distal femoral arthroplasty) involving a single manufacturer’s implant system at a large tertiary-level academic health sciences center. We collected reasons for surgery, implant survivorship, reasons for revision, and clinical outcomes (Short Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores).ResultsSeventy-six cases of hinged knee implants using the knee system under investigation were performed (39 hinged total knee and 37 distal femoral replacements) between 2011 and 2018, inclusive. Indications for surgery varied, with second-stage reimplantation most common for rotating hinge and fracture most common for distal femoral arthroplasty. There were 6 revisions in the rotating hinge group (none for aseptic loosening) and 5 in the distal femoral arthroplasty group (1 for aseptic loosening). Average follow-up was 2.89 ± 2.09 years. Postoperative Short Form 12 (Physical Component), Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores were 30.12 ± 10.17, 55.90 ± 21.51, and 115.62 ± 45.20, respectively.ConclusionThis novel hinged knee system is a highly durable option for complex and revision knee arthroplasty. Early failures tend to be secondary to infection. We observed only a single case of aseptic loosening. Although these early results are encouraging, ongoing follow-up is required to determine long-term prognosis in patients receiving this implant.     

Comparison of functional outcomes and complications of cemented vs uncemented total hip arthroplasty in the elderly neck of femur fracture patients: A systematic review and meta-analysis

PurposeThe neck of femur fractures in the elderly is a global concern. These fractures impair the quality of living and add to morbidity and mortality. A Multitude of treatment options for the same. This systematic review focuses on evaluating outcomes between cemented and uncemented total hip replacement in the elderly population with neck of femur fractures.Material and methodsThe search was conducted in databases PubMed, Embase, Scopus, open grey, and Cochrane following PRISMA guidelines. The studies fulfilling the inclusion criteria were included, scrutinized for data analysis, and also quality appraisal of all the included studies was conducted to be included in this article.ResultsA total of 7 studies were included (2 RCT, 5 retrospective studies) comprising 1171 THRs. Data analysis showed a higher HHS in cemented compared to uncemented(p < 0.001). The uncemented group had a significantly higher rate of revision, dislocation, and periprosthetic fracture compared to cemented group(p < 0.001). However, VAS score, loosening rates, and heterotopic ossification were similar in both statistically insignificant groups.ConclusionChoosing between cemented and uncemented techniques had been a controversy with lesser data due to higher morbidity and mortality. This systematic review provides information regarding functional outcomes and complications in both groups. The cemented group had better outcomes and lesser complications which should be preferred in elderly patients as the conclusion of this study. However, a larger RCT with better follow-up is still required.Level of evidenceLevel I, systematic review and meta-analysis.     

Megaprosthetic reconstruction for periprosthetic or highly comminuted fractures of the hip and knee

Objectives

To present the experience of a tertiary referral hospital in the management of a case series with hip or knee fractures by using modular megaprosthesis.

Patients and methods

Seventeen consecutive patients with highly comminuted fractures of the knee (n = 2), periprosthetic fractures of knee (n = 10) or hip (n = 5) were included. Fractures were managed with modular megaprosthesis (including total hip in 2 cases). Postoperative complications like infection and instability and outcome measures like return to previous mobility and living were recorded.

Results

The mean age at time of surgery was 77 years (25–91), and mean follow-up was 44 months (13–98). We had no intra-operative complications. There were 3 deep periprosthetic infections, 1 hip and 2 knee. In the hip group, including total femur patients, we had 2 dislocations (2/7), both managed with closed reduction. No aseptic loosening was seen. 15/17 patients regained walking ability, and 16 were discharged to independent living. Nine patients have died at the time of follow-up.

Conclusions

In these often old and physically compromised patients with highly comminuted fractures or complicated periprosthetic fractures, modular megaprosthesis could be a good surgical option. It can provide immediate stability and allow early mobilization.

     

Outcomes of Cemented Distal Femoral Replacement Using “Line to Line” Technique With All-Polyethylene Tibial Implant for Tumors

BackgroundBoth cemented and cementless stemmed endoprosthetic implants have been used to reconstruct large skeletal defects after tumor resection with similar outcomes. In this study, we examined the oncologic, clinical, and functional outcomes in patients undergoing distal femur replacement using the French paradox technique.MethodsA total of 125 patients who underwent distal femur replacement between 1990 and 2019 using the line-to-line cementation technique were reviewed. Implant failure was recorded as per Henderson’s classification. Functional outcomes were analyzed using the Musculoskeletal Tumor Society and Toronto Extremity Salvage Score scoring systems. The mean follow-up was 84 (1-350) months.ResultsAseptic loosening of the femoral stem was recorded in one patient at 21-years of follow-up. Twenty of 125 patients required bushing exchange for polyethylene wear, all after 10 years. Six tibial bearing component fractures were recorded in four patients while one femoral stem component Morse taper fractured. Two all-polyethylene cemented tibial implants were revised for polyethylene granuloma. Deep surgical site infection occurred in 13 patients, while six patients experienced local recurrence. Kaplan-Meier estimates for implant survival for all-cause revision were 85% at 1 year and 70% at 5 years. These estimates for femur or tibia loosening as an end point were 96% at 10 years and 90% at 15 years. The mean Musculoskeletal Tumor Society and Toronto Extremity Salvage Score scores at the last follow-up were 76% and 74%, respectively. Thirty-five patients died of disease progression.ConclusionThe line-to-line cementation technique, used with all-polyethylene tibial implants, demonstrates low incidence of aseptic loosening at medium and long-term follow-ups.Level of EvidenceIII.     

Outcomes of fixation for periprosthetic tibia fractures around and below total knee arthroplasty

IntroductionThe incidence of periprosthetic fractures after total knee arthroplasty (TKA) is rising due to an increasing number of TKAs performed annually and the growing elderly population. Like periprosthetic fractures of the distal femur, periprosthetic tibia fractures are primarily treated with operative fixation; however, there is limited scientific literature that has reported outcomes of periprosthetic tibia fractures treated with modern plating techniques. To our knowledge, this is the largest series of non-intraoperative periprosthetic tibia fractures treated with open reduction internal fixation (ORIF) ever reported.MethodsRetrospective chart review of 4557 operatively treated tibia fractures with ORIF over a 16-year period at two Level 1 Trauma Centers.Results38 patients with an average follow-up of 15.3 months (range 3–24) were identified. 11 (28.9%) fractures were in the proximal tibia (four with extension into the plateau (Felix 1A) and seven adjacent to the tibial stem (Felix 2A)), six (15.8%) in the midshaft/diaphysis (Felix 3A), and 21 (55.3%) in the distal 1/3rd (metaphysis, Felix 3A). 76.3% (29/38) of fractures united by 6 months following the index procedure, leaving 9 nonunions. The overall re-operation rate was 31.6% (12/38). There were no significant differences in rates of union (p = 1.00), reoperation (p = 0.66), superficial infection (p = 0.66), or deep infection (p = 0.31) in patients treated with single versus dual plating.ConclusionPeriprosthetic tibia fractures are difficult to treat and have a high risk of nonunion and reoperation even with modern plating techniques. Most patients can be treated to union with operative fixation and do not require revision arthroplasty, if the components are stable initially. We recommend dual plating for fractures in the proximal third, and either single plating or nailing for fractures in the middle and distal thirds depending on bone quality, implant positioning, and fracture morphology.     

Retrograde femoral nailing in elderly patients: outcome and functional results

Functional outcome after retrograde femoral intramedullary nailing was investigated in 35 patients older than 60 years (mean, 86 years) with 36 fractures, comprising 15 (41.7%) shaft and 21 (58.3%) distal fractures; overall, 7 (19.4%) periprosthetic fractures occured. Twenty-two (62.9%) of 35 patients were evaluated at a mean 16.5-month follow-up with the Lyshom-Gillquist score and the SF-8 questionaire. Primary union rate was 97.8%, with no significant differences in duration of surgery, bone healing, mobilization, and weight bearing among different fracture types; periprosthetic fractures revealed a significantly delayed mobilization (P=.03). Complications occured significantly more often among distal femoral fractures (P=.009), including all revision surgeries. The most frequently encountered complication was loosening of distal locking bolts (n=3). Lysholm score results were mainly influenced by age-related entities and revealed fair results in all fractures (mean in the femoral shaft fracture group, 78.1 vs mean in the distal femoral fracture group, 74.9; P=.69), except in the periprosthetic subgroup, which had good results (mean, 84.8; P=.23). This group also had increased physical parameters according to SF-8 score (P=.026). No correlation existed between SF-8 physical parameters and patient age or surgery delay, whereas a negative correlation existed between patient age and SF-8 mental parameters (P=.012). Retrograde femoral intramedullary nailing is commonly used in elderly patients due to reliable bone healing, minimal soft tissue damage, and immediate full weight bearing. It also offers a valid alternative to antegrade nailing in femoral shaft fractures.     

Low body mass index is a risk factor for increased post-operative mortality and poor functional improvement in distal femur fractures among patients aged over 65: A multicentre (TRON) study

BackgroundDistal femur fractures have been reported to have a mortality rate comparable to hip fractures, but the risk is still unknown. Recent studies have reported that low body mass index (BMI) is a risk factor for mortality in the elderly. We investigated the efficacy of low BMI for predicting the risk of mortality in distal femur fractures in patients aged over 65 within 18 months after injury and its impact on postoperative clinical outcomes and mortality.MethodsData from patients followed for more than six months were obtained from our trauma research group's database. We investigated risk factors for increased mortality using Cox proportional hazards models. We divided the analysed cases into low (<18.5 kg/m²) and high (>18.5 kg/m²) BMI groups. We adjusted the background characteristics of the groups by patient matching, and evaluated the postoperative mortality, complication rate, and knee society score (KSS).ResultsWe identified 216 patients, including 58 (26.9%) with low BMI values. Low BMI was an independent risk factor for mortality in all models (Hazard Ratio: 2.9, p = 0.011). The overall survival rate of the low BMI group at 18 months was significantly lower than that of the high BMI group (70.7% vs. 89.1%; p = 0.003). The complication rates of the low BMI and high BMI groups were not significantly different (33.3% vs. 22.2%; p = 0.283). The mean KSS values at 3, 6, and 12 months in the low BMI group was significantly worse than that in the high BMI group (78.7 ± 16.2 vs. 84.8 ± 13.1; p = 0.035, 82.2 ± 16.9 vs. 89.7 ± 8.9; p = 0.005, 86.4 ± 13.0 vs. 91.4 ± 8.4; p = 0.020, respectively).ConclusionsOur study indicated that low BMI was independent associated with increased mortality and impaired postoperative functional recovery in distal femur fractures of the elderly patients.     

Mid-Term Results After 517 Primary Total Hip Arthroplasties With a Shortened and Shoulderless Double-Taper Press-Fit Stem: High Rates of Aseptic Loosening

BackgroundShorter double-taper stems with reduced lateral shoulders facilitate implantation via the muscle-sparing direct anterior approach and are becoming increasingly popular. We observed an unusually high number of cases of aseptic loosening with the use of a modified stem. Therefore, the aim of this prospective single-center study was to assess safety and efficacy of this cementless stem.MethodsA total of 486 consecutive patients receiving 517 primary total hip arthroplasties using the MonoconMIS stem were prospectively followed up for a mean period of 5.29 years (standard deviation [SD], 1.47). Surgical and clinical data, complications, and revision surgeries were analyzed. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) score was recorded before surgery and at one year and five years after surgery.ResultsThe overall 5-year implant survival rate was 95.2%. The individual component survival rates were 96.1% for the stem, 99.4% for the acetabular cup, and 99.0% for the isolated mobile component exchange. The most common reasons for revision were periprosthetic fracture (1.5%), aseptic stem loosening (1.4%), and infection (1.0%). The WOMAC score improved significantly from 49.57 (SD, 21.42) at baseline to 13.33 (SD, 16.47) at one year and 9.84 (SD, 14.45) at five years after surgery. Aseptic stem loosening occurred only in patients with Dorr type A proximal femur morphology.ConclusionThe evaluated femoral stem is associated with revision rates higher than what has been reported for other implants. The WOMAC scores suggest adequate efficacy. Our data do not support the use of the MonoconMIS for primary total hip arthroplasty in patients with Dorr type A proximal femur morphology.     

Prevalence of Postoperative Periprosthetic Femur Fractures Between Two Different Femoral Component Designs Used in Direct Anterior Total Hip Arthroplasty

BackgroundPeriprosthetic femur fractures are a well-documented complication following direct anterior uncemented total hip arthroplasty. The purpose of this study is to compare the prevalence of postoperative periprosthetic femur fractures between 2 different femoral component designs used in direct anterior total hip arthroplasty.MethodsBeginning in February 2015, a single fellowship-trained adult reconstruction surgeon performed 361 consecutive direct anterior total hip replacements using a flat, single-taper, wedged femoral implant. In June 2016, that same surgeon, using the exact same surgical technique and postoperative weight-bearing protocol, began using a dual-taper, hydroxyapatite-coated implant for 789 consecutive hips. The patients were carefully monitored for 3 months after surgery to identify the frequency of periprosthetic femur fractures. A Fisher’s exact test was used to determine if the prevalence of periprosthetic femur fractures differed between the 2 implant designs.ResultsFive of 361 (1.4%) patients sustained proximal femur fractures at an average of 19.6 days postoperatively in the first group, all demonstrating a Vancouver type B2 periprosthetic fracture and requiring femoral revision. No patients (0/789, 0%) in the second cohort sustained a postoperative, periprosthetic fracture (P = .006).ConclusionIn this comparison of 2 consecutive cohorts, the dual-taper, hydroxyapatite-coated implant had a statistically significant lower postoperative periprosthetic fracture rate than a flat, single-taper, wedged design.     

Distal femoral replacement for selective periprosthetic fractures above a total knee arthroplasty

Background and aim

The management of distal femur periprosthetic fractures in the elderly remains a challenge. The aim of this study was to evaluate the results of distal segmental femur replacement as an alternative to fixation in complex distal femoral periprosthetic fractures in elderly patients.

Methods

Twelve patients were included in this prospective study, with a mean age of 78 years (range 68–90 years); incidentally, all were female. Fractures of the distal femur were classified as per Kim et al.’s classification (Clin Orthop Relat Res 446:167–175, 2006); our series included eight patients with type III and four patients with type II periprosthetic fractures. All 12 patients were treated with segmental distal femur replacement (Zimmer Inc., Warsaw, IN, USA). Nine patients required 90 cm and three patients required 130 cm of distal femur segment with a rotating hinge knee prosthesis.

Results

The mean follow up period was 20 months (range 15–28 months), with no major surgical complications reported. The mean duration of hospital stay following surgery was 12 days (range 7–36 days). All patients were mobilising full weight-bearing by day 3. All patients returned to their prior living arrangements. Ten patients returned to their original domicile, with one patient being discharged to a care home requiring minimal ambulatory assistance. The remaining two patients returned to their care homes.

Conclusions

WOMAC scores improved from the pre-injury state with a mean of 49.62 to 72.54 post-surgery (p-value of 0.0001). The Knee Society scores, possible only following surgery, had a mean value of 72. The mean VAS pain score was 1.75 (0 = no pain to 10 = worst pain ever felt). The average range of knee flexion was from 4° to 89° (range ?5° to 110°). The mean SF-36 physical functioning score was 45.64 [range 40.70–48.90; standard deviation (SD) ?2.62] and the mean SF-36 mental functioning score was 52.94 (range 45.8–57.70; SD ?3.38).     

Locking compression plate versus revision-prosthesis for Vancouver type B2 periprosthetic femoral fractures after total hip arthroplasty

IntroductionRevision arthroplasty is currently the recommended treatment for periprosthetic femoral fractures after primary total hip arthroplasty (THA) and stem loosening (Vancouver B2). However, open reduction and internal fixation (ORIF) utilizing locking compression plate (LCP) might be an effective treatment with a reduced surgical time and less complex procedure in a typically elderly patient collective with multiple comorbidities. The purpose of this study was to compare the functional and radiographic outcomes in two cohorts with Vancouver B2 periprosthetic femoral fractures after primary THA, treated either by ORIF with LCP fixation, or by revision arthroplasty utilizing a non-cemented long femoral stem.Materials and Methods36 patients with Vancouver B2 periprosthetic femoral fractures following THA, who had been treated between 2000 and 2014, were reviewed. Eight fractures were treated with LCP fixation, fourteen fractures with the first-generation revision prosthesis (Helios^®), and fourteen fractures with the second-generation revision prosthesis (Hyperion™). The patients were assessed clinically with the Parker mobility score and radiographically.ResultsA total of ten males and 26 females formed the basis of this report with an average age of 81years (range, 64 to 96 years). All fractures treated with LCP fixation alone healed uneventfully and there were no signs of secondary stem migration, malalignement or plate breakage. The average surgical time was shorter in the ORIF cohort; however, the results were not statistically significant. The postoperative Parker mobility score at latest follow-up showed no difference between the groups.ConclusionsAccording to the results of the current study, we conclude that the use of LCP fixation can be a sufficient option for the treatment of Vancouver B2 periprosthetic femoral fractures correspondingly with femoral stem loosening.