Three-phase bone scintigraphy pattern of loosening in uncemented hip prostheses

The three-phase bone scintigraphy pattern of loosening in uncemented hip prostheses (UHPs) has not previously been elucidated. We evaluated 28 patients with complicated UHPs who had undergone total hip arthroplasty a very long time previously (range 3–20 years, mean 8.4). All the patients were surgically reviewed: 26 UHPs were found to be loosened and two infected. Nine asymptomatic UHPs were taken as controls. The dynamic phase was invariably negative in both loosened and asymptomatic UHPs while markedly positive in the infected ones. The blood pool phase was positive to various degrees in 16 of the 26 loosened UHPs as well as in the infected UHPs, but was invariably negative in painless replacements. In the bone phase, areas of significantly (discrete to marked) increased uptake were observed in all the loosened prostheses as well as in two-thirds of the asymptomatic ones. However, the regions of the lesser trochanter and/or tip and/or shaft were involved exclusively in the case of the loosened UHPs, and diffuse periprosthetic uptake was found only with loosened or infected implants. Areas of slight methylene diphosphonate (MDP) uptake were found at every periprosthetic site and areas of discrete to marked MDP uptake were commonly found in the acetabulum and/or the greater trochanter with both loosened and painless prostheses and are thus considered to be nonspecific findings.     

Tibial component positioning in total knee arthroplasty: bone coverage and extensor apparatus alignment

Correct positioning of the tibial component in total knee arthroplasty (TKA) must take into account both an optimal bone coverage (defined by a maximal cortical bearing with posteromedial and anterolateral support) and satisfactory patellofemoral tracking. Consequently, a compromise position must be found by the surgeon during the operation to simultaneously meet these two requirements. Moreover, tibial tray positioning depends upon the tibial torsion, which has been shown to act mainly in the proximal quarter of the tibia. Therefore, the correct application of the tibial tray is also theoretically related to the level of bone resection. In this study, we first quantified the torsional profile given by an optimal bone coverage for a symmetrical tibial tray design and for an asymmetrical one. Then, for the two types of tibial trays, we measured the angle difference between optimal bone coverage and an alignment on the middle of the tibial tubercule. Results showed that the values of the torsional profile given by the symmetrical tray were more scattered than those from the asymmetrical one. However, determination of the mean differential angle between the position providing optimal bone coverage and the one providing the best patellofemoral tracking indicated that the symmetrical prosthetic tray offered the best compromise between these two requirements. Although the tibiofemoral joint is known to be asymmetric in both shape and dimension, the asymmetrical tray chosen in this study was found to fulfill this compromise with more difficulty. Received: 8 November 1996 Accepted: 7 April 1997     

Patients’ perspective on controversial issues in total knee arthroplasty

We investigated the level of patient knowledge and preferences over the currently controversial issues in TKA. One hundred patients who had decided to undergo TKA for advanced osteoarthritis were asked to complete a questionnaire inquiring their knowledge and preferences over three controversial issues: (1) computer assisted surgery (CAS), (2) minimal invasive surgery (MIS), and (3) ceramic femoral component. The patient preferences over the three issues were questioned again after they had been informed of advantages and disadvantages of each option using an explanatory document. Most (more than 75%) of the patients did not have sufficient knowledge and their knowledge was based on non-professional sources (more than 85%). Before the information was given, most (more than 80%) of the patients preferred a new option. After the information was provided, more patients preferred a standard option in the issues of CAS (60%) and MIS (88%). This study prompts health care providers to become more active in providing accurate information and to consider patients perspective in making decisions which will influence the benefits and risk of the patients.     

Arthrodesis of the knee after failed infected total knee arthroplasty

Infection after total knee arthroplasty (TKA) can be a challenging and difficult problem to treat. In selected patients, knee arthrodesis is a well-recognized salvage procedure after infected TKA. The authors retrospectively reviewed their experience with this treatment option, presenting 20 patients (8 women, 12 men), performed between 1990 and 2002. The average age was 67 years (range: 47–81 years) and the mean number of previous surgical procedures was 6 (range: 4–11 procedures). There were multiple indications for knee arthrodesis, including extensive bone or soft tissue loss, poor bone stock, and recurring infections. One-stage fusion was done in 7 knees while, on the other 13, arthrodesis was performed as two-stage fusions. The average clinical follow-up was 4.5 years (range: 2–11 years). 18 of the 20 patients were interviewed and graded using the Visual Analogue Scale (VAS) for pain, the Short Form-36 Health Survey (SF-36), and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire that has knee-related quality of life items. According to the VAS, the mean intensity was 3.4 points. 6 (33%) of the patients had no difficulty with the knee and 9 (50%) of them had mild or moderate difficulty. The SF-36 scores were similar to those for normative data for patients after TKA, with only the social functioning, role emotional, and physical functioning scores being lower and the role physical and social functioning scores being higher. Three of 20 fusions failed, whereas two knees became non-infected non-unions. In one, the knee infection persisted and required above-knee amputation. The two-stage arthrodesis gave the most predictable rate of fusion. Persistent infection and extensive bone stock losses led to failure even under the best circumstances. In our opinion, arthrodesis of the knee is a satisfactory salvage procedure following a failed TKA, and can provide reliable expectation for a stable, painless extremity for high-functioning patients who are able to walk.     

The femoral sulcus in total knee arthroplasty

The position of the femoral sulcus relative to the midline of the distal femoral resection in total knee arthroplasty (TKA) was studied to determine if centralized placement of the femoral component on the distal femur was justified in terms of aligning the prosthetic sulcus with the native femoral sulcus. The location of the femoral sulcus was studied in 112 consecutive patients undergoing TKA. The mean sulcus position was 0.7 mm lateral to the midline of the distal femoral resection (SD 1.4, 95% CI, 0.5–1.0 mm). However, the variation in sulcus positions ranged from 4 mm medial to 4 mm lateral to the midline. The mean sulcus position in valgus knees was 1.0 mm lateral to the midline (SD 1.8), and that in varus knees was 0.7 mm lateral to the midline (SD 1.2) (P = 0.501). It appears prudent to centre the femoral component on the native sulcus rather than the midline of the distal femoral resection, so as to ensure accurate alignment of the prosthetic sulcus with the native sulcus and to encourage normal patella tracking.     

Legion假体在膝外翻畸形初次全膝关节置换手术中应用疗效

目的探讨Legion假体在膝外翻畸形初次全膝关节置换手术中的临床应用疗效。方法回顾性分析沈阳军区总医院骨科2012年1月至2015年12月收治的膝外翻畸形患者32例(37膝)。记录患者术后髌股轨迹、切口愈合情况、膝外翻矫正角度、膝关节Harris评分(HSS)。结果所有患者术后均获得随访。32例患者膝关节髌股轨迹良好,切口愈合情况佳,无感染发生。34膝完全矫正了膝外翻畸形,仅余3膝存在3°~5°膝外翻遗留。患者HSS评分由术前34.5分提升至术后87.0分。结论在膝外翻畸形患者的初次膝关节置换手术中应用Legion假体可以达到满意的手术疗效,术后患者膝关节稳定,大部分患者的膝外翻畸形得到了纠正,患者在术后早期功能锻炼即可达到屈曲90°、伸直0°。     

Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty

BackgroundDespite the success rate of Total Knee Arthroplasty (TKA), many patients undergo contralateral TKA. It is possible that altered gait mechanics after unilateral TKA play a role in the progression of contralateral OA progression.Research questionThe purpose of this study was to identify biomechanical predictors of radiographic OA progression in the contralateral (non-surgical) knee after unilateral (primary/initial) TKA. In addition, this study quantified for patients who had contralateral OA progression.MethodsBiomechanical outcomes were collected 6–24 months after unilateral primary TKA and were used to predict changes in contralateral OA severity at follow-up. Participants were divided into “Progressor” and “Non-Progressor” groups based on changes in Kellgren-Lawrence (KL) OA grade and Joint Space Width (JSW) between baseline and follow-up testing sessions. Biomechanical factors during walking were peak knee adduction moment, knee flexion/extension excursions, knee angle at initial foot contact, and peak knee flexion/extension. Multiple independent t-tests were used to examine the magnitude of differences in biomechanical variables between the groups. Logistic regression was used to examine the association between the biomechanical predictors and change in KL scores and JSW.ResultsThe mean time between surgery and follow-up x-rays was 8.8 (2.4) years. Of 40 participants, 62.5–78% had contralateral radiographic knee OA progression by follow-up. There were no significant differences in the biomechanical variables between groups. For the regression analysis, none of the biomechanical variables were found to be predictors for contralateral OA progression.SignificanceAlthough abnormal biomechanics are known risk factors for primary knee OA, it is possible that the mechanisms that result in OA progression of the contralateral limb are different than primary knee OA progression. Future work should evaluate other objective measures of OA progression and determine if cumulative measures of joint loading are related to OA worsening.     

Bone marrow edema in the knee in osteoarthrosis and association with total knee arthroplasty within a three-year follow-up

OBJECTIVE: The purpose of this study was to determine if a correlation exists between magnetic resonance imaging (MRI) findings of bone marrow edema (BME) in osteoarthrosis (OA) of the knee joint and need for total knee arthroplasty (TKA) within a follow-up period of 3 years. MATERIALS AND METHODS: The entire database of knee MR studies over a 3-year period was used to select individuals with knee OA. A chart review was conducted to identify and include only those who had a 3-year follow-up appointment from the time of the initial MR study. There were 25 patients in the OA-only group (four men and 21 women; age range, 28-75; average age, 49.3 years). The OA and BME group had 48 patients (23 men and 25 women; average age, 55.5 years). The MRs were reviewed and interpreted by a musculoskeletal radiologist and were classified into one of four patterns of BME: none, focal, global, or cystic pattern. Meniscal tear and degree of cartilage loss were also assessed. RESULTS: Subjects who had BME of any pattern type were 8.95 times as likely to progress rapidly to a TKA when compared to subjects with no BME (p = 0.016). Subjects with a global pattern of BME were 5.45 times as likely to have a TKA compared to subjects with focal, cyst, or no BME (p < 0.05). Subjects with a global edema pattern were 13.04 times as likely to have a TKA than subjects with no marrow edema in the knee (p < 0.01). There was no correlation of TKA with meniscal tear or cartilage loss. The group of subjects who had a TKA were 12.6 years older than those who did not have a TKA (p < 0.001). However, the BME results were still significant after accounting for the age difference. CONCLUSION: Our classification of patterns into global, focal, cystic, and absence of BME is an attempt to further define edema in osteoarthrosis and how it relates to clinical progression. Patients with BME and OA have an increased risk of TKA as opposed to OA and no marrow edema. The BME pattern with the worst prognosis for the knee is the global pattern.     

Computer-assisted surgery can reduce blood loss after total knee arthroplasty

The aim of this study was to compare blood loss and transfusion requirements in patients undergoing computer-assisted total knee arthroplasty (TKA) and patients operated with conventional instrumentation with intra-medullar guides. A prospective randomized study of 87 patients undergoing a TKA assigned to conventional technique (n = 44) or computer-assisted surgery (n = 43) was conducted. All patients were operated by the same surgeon and in all cases a cemented arthroplasty and deep recovery drainage were used. Both groups were comparable in all variables except for duration of ischemia, which was 13.7 min higher in the computer-assisted group. Blood loss due to drainage was higher in the conventional technique group (613 vs. 447 ml), as was the number of patients in which blood from the blood recovery system was reinfused (53 vs. 23%). Those patients undergoing computer-assisted surgery experienced less bleeding than those operated with the conventional technique. However, hemoglobin drop and allogenic transfusion rate were not statistically different in both groups.     

Effect of improvement in quadriceps strength asymmetry on trunk movement asymmetry after total knee arthroplasty

BackgroundPatients with knee osteoarthritis (OA) demonstrate trunk movement asymmetry during walking; this asymmetry is associated with disability and quadriceps strength asymmetry.Research questionWhat are the differences between trunk movement asymmetries before and after total knee arthroplasty (TKA) and associations between the changes in trunk movement asymmetry and quadriceps strength asymmetry?MethodsIn this prospective cohort study, 27 patients (mean age, 71.0 years; women, 85.2%) were assessed at 1 month before and 6 months after surgery. Trunk movement asymmetry (harmonic ratio) was assessed at their preferred pace using a triaxial accelerometer. The isometric quadriceps strength was evaluated using a hand-held dynamometer, and the quadriceps strength inter-limb absolute difference was calculated. Multivariate analyses were performed to compare the trunk movement asymmetries before and after surgery with covariate adjustment (gait pain, gait velocity, and non-operated-limb Kellgren and Lawrence [K&L] grade) and to investigate the association between the changes in trunk movement asymmetry and quadriceps strength inter-limb difference with covariate adjustment (age, sex, and non-operated-limb K&L grade).ResultsThe trunk movement asymmetry in the medio-lateral (mean difference, 0.61; 95% confidence interval [CI], 0.22 to 1.00) and antero-posterior (mean difference, 1.15; 95% CI, 0.48 to 1.83) directions significantly decreased postoperatively compared with the preoperative results. A decreased quadriceps strength inter-limb difference was significantly associated with a decreased medio-lateral trunk movement asymmetry (β = 0.68; 95% CI, 0.30 to 1.06).SignificanceTKA plays an important role in the improvement of trunk stability during walking in patients with knee OA. Decreasing quadriceps strength asymmetry may be a key to improving trunk movement asymmetry.     

快速康复理念在骨肉瘤人工膝关节置换术围术期中应用

目的探讨快速康复理念在骨肉瘤人工膝关节置换术围术期实施方法及效果观察。方法选取中国医科大学附属第四医院骨外科自2013年10月至2017年1月收治的15例采用人工膝关节置换术治疗的骨肉瘤患者设为快速康复组,围术期采用快速康复理念管理;18例采用人工膝关节置换术治疗的骨肉瘤患者设为常规组,实施常规治疗。比较两组的术后康复情况。结果快速康复组患者术后下床活动时间明显早于常规组,并发症明显少于常规组,术后膝关节活动度的优良率明显高于常规组,随访3个月时的膝关节功能评分明显高于常规组,两组间比较,差异均有统计学意义(P<0.05)。结论对骨肉瘤人工膝关节置换术的患者围术期实施快速康复管理,能够促进术后康复。     

Soft tissue tension in extension in total knee arthroplasty affects postoperative knee extension and stability

The purpose of this study was to assess correlation of soft tissue tension in extension with postoperative extension deficit and valgus/varus instability. Sixty-four osteoarthritic knees that underwent primary total knee arthroplasty were investigated. Soft tissue tension in extension was measured during operation with a balancer/tensor device. Extension deficit was measured, and valgus/varus laxity was assessed by stress radiographs in extension and 30°-flexion 1 year after operation. The extension deficit became larger with an increase of soft tissue tension a year after operation. (P < 0.05) The varus laxity in extension and 30°-flexion and valgus laxity in 30°-flexion became smaller with an increase of soft tissue tension (P < 0.05). Our results demonstrated that soft tissue tension during operation affects postoperative knee extension and stability. An erratum to this article can be found at     

Multilobulated popliteal cyst after a failed total knee arthroplasty

Popliteal cyst is a rare finding after total knee arthroplasty (TKA), but when present, it might indicate a malfunction of the TKA related to generation of wear-particles, or loosening. We present a case of a multilobulated popliteal cyst developing in a patient 8 years after primary TKA. The cyst was associated with a mechanical prosthetic loosening. The primary complaint of the patient was pain in the posterior region of the knee. A two-stage procedure consisting of cyst excision at first, followed after 5 months by a revision TKA was performed. Intraoperatively, a darkish, multilobulated cyst with a well-defined thick wall filled with fluid containing polyethylene debris, communicating with the knee joint was found. After 3 years of follow-up, the patient was satisfied and walked without the support of a cane. The patient presented a satisfactory knee range of motion. Clinical, radiological and ultrasound investigations ruled out popliteal cyst recurrence. A dissecting popliteal cyst associated with a failed TKA should be excised because it contains polyethylene debris that constitutes an induced factor for prosthetic loosening. A two-stage procedure with quite a long time in-between, as presented in this paper, can be a useful alternative to manage such a problem, in particular in very old patients associated with other medical problems.     

Measurement of joint gap load in patella everted and reset position during total knee arthroplasty

An original tensor system was developed to directly measure the load between femoral trial component and tibial cut surface in vivo in both patella everted and reset positions during total knee arthroplasty (TKA). We used this system during posterior-stabilized (PS) and cruciate-retaining (CR) TKA. In PS-TKA, there was no significant difference between the loads in extension in patella everted position and reset position. In flexion, however, there was significant increase of load in patella reset position compared to in everted position. In CR-TKA, there was no significant difference between the loads in patella everted position and in patella reset position in either extension or flexion. It was found that the effect of patella position on joint gap load was different between PS-TKA and CR-TKA. It is important to be aware that, when performing PS-KA, the load in flexion gap will increase, in other words, flexion gap distance will decrease by resetting the patella.     

Lower extremity gait kinematics outcomes after knee replacement demonstrate arthroplasty-specific differences between unicondylar and total knee arthroplasty: A pilot study

BackgroundThe aim of the present study is to compare sagittal gait kinematics of ankle, knee and hip joints between subjects with unicondylar and total knee arthroplasty and age matched healthy controls. Since unicondylar knee replacement is a less invasive procedure, which more closely preserves knee joint anatomy, we hypothesized that one year post unicondylar knee arthroplasty patients would demonstrate more normal gait patterns than patients with total knee arthroplasty.Research questionDo unicondylar and total knee arthroplasty patients display similar gait kinematics one year after surgery?MethodsFourteen subjects (8 posterior stabilized and 6 medial unicondylar knee replacements) that were one year post surgery, and 6 healthy control subjects underwent a 3D gait analysis and a physical examination (range of motion, muscle strength). Statistical parametric mapping was used to compare gait kinematics of the lower limbs between groups. Additionally, differences in peak angles and clinical outcomes were assessed using a one-way ANOVA between subjects analysis.ResultsBoth knee replacement groups showed reduced knee flexion range of motion and reduced muscle strength at the operated leg compared to the control group. Subjects with TKA demonstrated reduced knee flexion at loading response and midstance of the gait cycle. Both UKA and TKA demonstrated significantly less knee flexion during swing.SignificanceThe results of this study demonstrate arthroplasty-specific differences in muscle strength, range of motion and gait kinematics of the lower limb one year after knee surgery. Future planning of post-surgery follow-up should addresses these arthroplasty-specific weaknesses and gait deviations.     

Survival curve and factors related to drainage during the first 24 h after total knee arthroplasty

Routine use of drains in total knee arthroplasty (TKA) is controversial. The aim of this study is to define the hourly risk of bleeding in the first 24 h following TKA using a survival study, to detect factors that might modify this risk, and establish a predictive model. In a retrospective study including 112 knees, patients with a coagulation disorder, platelet disease, or anticoagulation treatment were excluded. The risk factors studied included anesthesia score of the American society of anesthesiologists (ASA), proteinemia, total volume of fluid drained, and the use of low molecular weight heparin. The Kaplan-Meier test, Mantel-Haenszel test, and Cox regression analysis were used for the statistical calculations. The results indicate that the drains used in TKA can be removed within the first 18 h with a high degree of safety and low risk of persistent bleeding. The evolution of postoperative bleeding was independent of the factors studied.     

加速康复外科理念在膝关节置换术围术期应用

目的评价加速康复(ERAS)外科理念在膝关节置换术围术期的应用疗效。方法收集2015年1月至2016年1月收治的因膝关节骨性关节炎行膝关节置换术的82例患者,随机分为ERAS组(n=40)和常规组(n=42),比较两组围手术期疗效。结果患者82例随访1个月。所有患者切口均一期愈合,术后12 d拆线。ERAS组术中出血量、输血量均明显少于常规组,差异有统计学意义(P<0.05)。两组手术时间比较,差异无统计学意义(P>0.05)。ERAS组术后住院(8.0±3.4)d,明显低于常规组的(11.5±3.6)d,两组平均住院日比较,差异有统计学意义(P<0.05)。两组均未发生切口并发症。两组深静脉血栓、泌尿系统感染并发症发生率比较,差异无统计学意义(P>0.05)。比较术后12 d和术后1个月的膝关节KSS评分,ERAS组膝关节KSS评分优于常规组,差异有统计学意义(P<0.05)。结论 ERAS外科理论在膝关节置换围术期的应用能明显缩短术后住院时间和住院费用,可以促进患者膝关节功能的康复,值得推广和应用。     

Clinical experience with less invasive surgery techniques in total knee arthroplasty: a comparative study

We compared 25 consecutive cases of total knee arthroplasty performed through less invasive techniques with 25 cases of age and BMI matched cases of standard knee replacements. Early experience suggests functional recovery is earlier with less invasive technique as compared with open access. Patients in less invasive group had better knee flexion (an average of 116 degrees compared to 97 degrees ), walking ability and stair climbing at 6 months than those with standard technique at 6 months. At 2 years this difference was maintained to a lesser extent. More patients with less invasive group could kneel and could do "normal up and down" the stairs at 6 months and also at 2 years. There was no significant difference in alignment and component sizing between the two groups. This should translate to similar long term results after less invasive knee arthroplasty as after open access total knee arthroplasty.     

Influence of intra-operative joint gap on post-operative flexion angle in osteoarthritis patients undergoing posterior-stabilized total knee arthroplasty

Recently, we developed a new tensor for total knee arthroplasty (TKA) procedures enabling soft tissue balance assessment throughout the range of motion while reproducing post-operative joint alignment with the patello-femoral (PF) joint reduced and the tibiofemoral joint aligned. Using the tensor with a computer-assisted navigation system, we investigated the relationship between various intra-operative joint gap values and their post-operative flexion angles. An increased value during the extension to flexion gap and a decreased value during the flexion to deep flexion gap with PF joint reduced, not everted, showed an inverse correlation with post-operative knee flexion angle, not pre-operative flexion angle. In conclusion, understanding the characteristics of joint gap kinematics in posterior-stabilized TKA under physiological and reproducible joint conditions may enable the prediction of the post-operative flexion angle and help to determine the appropriate intra-operative joint gap.