残留内翻对弓形股骨患者全膝关节置换术后功能恢复的影响

目的探究残留内翻的下肢力线对弓形股骨患者行全膝关节置换术(total knee arthroplasty,TKA)术后功能恢复的影响。方法本研究回顾性收集西安市红会医院膝关节外科2015年1月至2015年12月,接受同一术者实施TKA的59例(71膝)骨关节炎患者的全部资料,其中男6例(8膝),女53例(63膝);年龄58~82岁,平均(67.7±5.7)岁。测量患者股骨侧弓角(femoral bowing angle,FBA)及下肢力线(hip-knee-ankle angle,HKA)。FBA<177°定义为弓形股骨。根据术后负重位标准正位X线片将患者分为两组:残留内翻组32例37膝(HKA<177°),中立位力线组27例34膝[HKA为(180±3)°]。以美国膝关节协会评分(knee society score,KSS)及西安大略和麦克马斯特大学骨关节炎指数评分(the western Ontario and McMaster universities osteoarthritis index,WOMAC)评价两组术后功能及症状。结果患者均获随访,随访时间43~55个月,平均随访时间为(49.30±4.11)个月。全部患者均未见假体松动、感染等严重并发症。两组患者术前KSS及WOMAC评分比较,差异无统计学意义(P<0.05);手术前后比较差异有统计学意义(P>0.05);术后残留内翻组WOMAC总分[(5.57±6.23)分]较中立位力线组[(9.27±8.86)分]明显降低,WOMAC C部分(日常生活困难程度)评分[(4.95±5.87)分]显著低于中立位力线组[(8.24±7.68)分],余各评分比较差异无统计学意义(P<0.05)。结论相比中立位力线,存在弓形股骨的患者行TKA术后下肢力线残留内翻可以获得更好的临床结局,但中远期疗效有待进一步观察。     

Less valgus alignment in total knee arthroplasty for the varus knee

Constitutional varus of the leg is well recognizable anatomically. Moreland[1] studied long standing radiographs of normal males with a range of varus from 2.6-3° in the proximal tibia. Victor et al. [2] reported constitution varus of 3 degree in 32% men, 17% women. The authors routine technique during total knee arthroplasty (TKA) is to cut the distal femur at 5° valgus and the tibia at neutral for the valgus leg and cut the distal femur at 5° valgus and the tibia 2° varus for varus aligned limbs. 127 consecutive long standing knee radiographs were not retrospectively studied pre and post operatively with 2 year minimum follow up. Average age was 68 years (range 51-90). Average weight was 215 lbs (range 110 – 333). Average tourniquet time was 32 minutes for all patients prior to closure.For the varus group (72 knees), average pre-op tibial femoral alignment was 3.3° varus (range 0-13°). Post-op tibial femoral alignment was 1.2° valgus (range 1° varus - 5° valgus) with the mechanical axis falling into the medial compartment in all patients. Average pre-op knee score was 88 and post-op was 180 at minimum of 2 years.For the valgus group (55 knees), average pre-op tibial femoral alignment was 7.5° (range 2°-24°) valgus. Average post-op tibial femoral alignment was 3.8° (range 1°-10°) valgus. Average pre-op knee score was 107 and post-op was 182 at minimum of 2 years. The authors agree with aiming for valgus alignment for the classic valgus leg (mechanical axis centered on hip, knee, ankle) and less valgus alignment for the varus knee (mechanical axis into the medial compartment). Following the patients anatomy eliminates the need for major soft tissue releases while still avoiding “malalignment”. No special soft tissue releases were required in any patient with pre-op varus or valgus alignment. The clinical outcome is not effected by leaving pre-op varus aligned extremities in less valgus with their TKA’s.     

The Impact of Mechanical and Restricted Kinematic Alignment on Knee Anatomy in Total Knee Arthroplasty

Background

Total knee arthroplasty (TKA), aiming at neutral mechanical alignment (MA), inevitably modifies the patient's native knee anatomy. Another option is kinematic alignment (KA), which aims to restore the original anatomy of the knee. The aim of this study was to evaluate the variations in lower limb anatomy of a patient population scheduled for TKA, and to assess the use of a restricted KA TKA protocol and compare the resulting anatomic modifications with the standard MA technique.

Femoral Lateral Bowing and Varus Condylar Orientation Are Prevalent and Affect Axial Alignment of TKA in Koreans

Background

Coronal alignment is considered key to the function and longevity of a TKA. However, most studies do not consider femoral and tibial anatomical features such as lateral femoral bowing and the effects of these features and subsequent alignment on function after TKA are unclear.

Questions/purposes

We therefore determined (1) the prevalence of lateral femoral bowing, varus femoral condylar orientation, and severe tibia plateau inclination in female Koreans undergoing TKA; (2) whether postoperative alignments are affected by these anatomical features and improved by the use of navigation; and (3) whether postoperative coronal alignments are associated with function.

Methods

We measured alignment in 367 knees that underwent TKA and 60 sex- and age-matched normal knees (control group). We determined patterns and degrees of femoral bowing angle, femoral condylar orientation, and tibial plateau inclination on preoperative full-limb radiographs. Postoperatively, coronal alignment of limbs and of femoral and tibial components was measured. We compared American Knee Society scores, WOMAC scores, and SF-36 scores in aligned knees and outliers (beyond ± 3° or ± 2°) at 1 year.

Results

The prevalence of lateral femoral bowing was 88% in the TKA group and 77% in the control group. Mean femoral condylar orientation angle was varus 2.6° in the TKA group and valgus 1.1° in the control group, and mean tibial plateau inclination was varus 8.3° in the TKA group and varus 5.4° in the control group. Femoral lateral bowing and varus femoral condylar orientation were associated with postoperative alignments. Several clinical outcome scales were inferior in the outliers in mechanical tibiofemoral angle, anatomical tibiofemoral angle, and tibial coronal alignment but not in femoral coronal alignment outliers.

Conclusions

Lateral femoral bowing, varus condylar orientation, and severe varus inclination of the tibia plateau should be considered when performing TKA in Korean patients or patients with otherwise similar anatomical features.     

Does Residual Varus Alignment Cause Increasing Varus Laxity at a Minimum of Five Years After Total Knee Arthroplasty?

Background

The purpose of this study is to investigate whether varus-valgus laxity of cruciate-retaining (CR) total knee arthroplasty (TKA) changes between 1 year and >5 years after surgery based on postoperative limb alignment.

Accuracy of Image-Free Computer Navigated Total Knee Arthroplasty Is Not Compromised in Severely Deformed Varus Knees

In severe varus knee deformity, image-free computer navigated total knee arthroplasty (TKA) may result in a malaligned knee. The aim of this study was to compare the results of 17 severe varus knees (≥ 20°) and 81 varus knees (< 20°) that underwent image-free computer navigated TKA and analyze postoperative malalignment. Computer navigated TKA was performed according to standard protocol, and component angles and mechanical axes were evaluated postoperatively with weight bearing full-length standing radiographs. All severe varus knees were corrected to within 3° of neutral lower limb alignment despite having a mean preoperative varus deformities of 22.4°. Neutral alignment was obtained in 88.9% of the varus group (mean preoperative varus deformity of 11.7°), without significant difference between the two groups. No significant difference was found in either the femoral or tibial component angles, or in the frequency of complications. Severity of varus deformity did not affect the accuracy of image-free computer navigated TKA.     

全膝关节置换术中股骨内髁滑移截骨治疗伴有关节外畸形的膝内翻

目的：探讨股骨内髁滑移截骨术（medial condyle sliding osteotomy, MCSO）在全膝关节置换术中纠正患者内翻膝关节外畸形的临床疗效。方法通过回顾性研究2013年1月至2015年12月在第三军医大学附属西南医院关节外科中心于全膝关节置换术中采用MCSO在关节内纠正股骨侧的关节外内翻畸形的12例患者,统计该组患者手术前后的股骨远端外侧力线角（mechanical lateral distal femoral angle, mLDFA）、髋-膝-踝（hip?knee?ankle, HKA）角、疼痛视觉模拟量表（visual analogue scale, VAS）评分及美国膝关节协会（American Knee Society, AKS）综合评分系统中的膝评分和功能评分等,评价MCSO纠正关节外的内翻畸形的效果。结果本组患者随访6~40个月,无感染、骨折、假体松动、截骨不愈合等并发症发生。本组患者手术前后的mLDFA分别为117.4°±4.7°、91.6°±1.4°;手术前后的HKA角分别为167.2°±9.8°、179.6°±1.6°;手术前后的VAS评分分别为（6.4±1.1）分、（1.8±1.5）分;手术前后的AKS膝评分分别为（60.2±17.6）分、（92.6±9.4）分;手术前后的AKS功能评分分别为（69.4±21.3）分、（87.6±14.9）分。手术前后以上指标的差异均有统计学意义（均P＜0.05）。结论在合并关节外畸形的内翻膝的关节置换手术中,采用MCSO技术可以正确纠正内翻力线,更容易实现伸屈间隙平衡,达到满意的手术疗效。能有效避免对膝关节后内侧和内侧组织结构的过度松解,从而避免单纯依赖软组织松解而导致的屈曲位内侧间隙松弛及髌股关节对位不良等问题。     

膝关节后交叉韧带保留型假体置换术15年远期疗效研究

目的 针对后交叉韧带(posterior cruciate ligament,PCL)保留型膝关节假体置换术进行15年以上临床随访研究,分析其临床疗效及失败原因.方法 对Medico-Chirurgical du Cedre中心1990年9月至1992年3月行PCL保留型全膝关节假体初次置换术获得随访的153例(178膝)患者的临床资料进行回顾性研究.对其采用术后X线测量结合随访时国际膝关节协会临床评分评估手术疗效,X线测量包括髋膝踝角(HKA)平均值、HKA绝对偏差、α角、β角、髌骨指数(AP/AT)、胫骨后倾角(PTA)等.以翻修率作为假体生存率最终评定标准.结果 153例患者随访时31例(49膝)死亡,4例(4膝)失访,获访118例(125膝).翻修11膝,15年以上假体生存率93.7%.翻修11膝原因分别为:9膝为假体界面无菌性松动(其中7膝伴严重骨溶解,2膝为胫骨假体周围透亮线伴疼痛),1膝反曲畸形,1膝内侧胫骨平台塌陷.术后随访时膝关节协会评分达173分,优良率95.9%.对比翻修患者与未翻修患者临床资料:对侧未手术膝关节内外翻角、术前正位X线片β角、两组手术前后膝关节协会评分差异均有统计学意义(P＜0.05).结论 PCL保留型假体可以较好地恢复膝关节生物力学特性,15年以上生存率优良.仅个别病例失败与PCL失效有关,聚乙烯衬垫后部过度磨损和髌股关节并发症少见.未手术侧膝关节畸形程度和术侧膝关节胫骨侧内翻畸形程度可能是影响假体翻修率的重要因素.     

Polyethylene Damage Increases With Varus Implant Alignment in Posterior-stabilized and Constrained Condylar Knee Arthroplasty

Background

Implant malalignment in primary TKA has been reported to increase stresses placed on the bearing surfaces of implant components. We used a longitudinally maintained registry coupled with an implant retrieval program to consider whether preoperative, postoperative, or prerevision malalignment was associated with increased risk of revision surgery after TKA.

Questions/purposes

(1) What is the relative polyethylene damage on medial and lateral compartments of the tibial plateaus from revised TKAs? (2) Does coronal TKA alignment affect implant performance, such that TKAs aligned in varus are predisposed to experience increased polyethylene damage? (3) Does TKA alignment differ between postoperative and prerevision radiographs, and if so, what does this difference suggest about the mechanical contact load placed on a knee with a TKA?

Methods

Between 2007 and 2012, we performed 18,065 primary TKAs at our institution. By March 2016, 178 of those TKAs (1%) were revised at our center at least 2 years after primary surgery at our institution. Eighteen of those TKAs were excluded from this analysis because the tibial insert was not explanted during revision surgery, and four more were excluded because the inserts were lost or returned to the patient before the study was initiated, leaving 156 retrieved polyethylene tibial inserts (in 153 patients) revised at greater than 2 years after the primary TKA for this retrospective study. Patients who underwent revision surgery elsewhere were not considered here, since this study depended on having retrieved components. Polyethylene damage modes of burnishing, pitting, scratching, delamination, surface deformation, abrasion, and third-body debris were subjectively graded on a scale of 0 to 3 to reflect the extent and severity of each damage mode. On preoperative, postoperative, and prerevision radiographs, overall alignment, femoral alignment, and tibial alignment in the coronal plane were measured according to the protocol recommended by the Knee Society.

Results

Knees with more overall varus alignment after TKA had increased total damage on the retrieved tibial inserts (Spearman’s rank correlation coefficients of −0.3 [95% CI, −0.4 to −0.1; p = 0.001]). We also found revised TKAs tended to drift back into greater varus before revision surgery, with a mean (SD) of 3.6° ± 4.0° valgus for postoperative alignment compared with 1.7° ± 6.4° prerevision (p = 0.04).

Conclusions

Despite surgical efforts to achieve neutral mechanical alignment, remaining varus alignment places an increased contact load on the polyethylene articular surfaces. The drift toward further varus alignment postoperatively is consistent with the knee adduction moment remaining high after surgery.

Clinical Relevance

While we found a predisposition toward recurrence of the preoperative varus deformity, we did not find increased medial as opposed to lateral polyethylene damage, which may be explained by the curve-on-curve toroidal design of the articulating surfaces of the TKA implants in this study.

     

Postoperative limb alignment and its determinants after minimally invasive Oxford medial unicompartmental knee arthroplasty

One hundred twenty-two consecutive minimally invasive Oxford phase 3 medial unicompartmental knee arthroplasties in 109 patients were evaluated for postoperative limb alignment and the influence of factors such as preoperative limb alignment, age, body mass index, sex, insert thickness, and surgeon's experience. The mean mechanical preoperative hip-knee-ankle (HKA) angle of 172.2° ± 3.1° improved to 177.1° ± 2.9° postoperatively. In 75% of the limbs, the HKA angle was restored to within an acceptable alignment of 177° ± 3°, 14% of the limbs were in excessive varus (<174°), and 11% were in valgus (>180°). Only preoperative HKA angle was predictive of postoperative HKA angle. Although most of the limbs had acceptable limb alignment after unicompartmental knee arthroplasty, limbs with more severe preoperative varus deformity had a tendency to remain in excessive varus, and limbs with lesser preoperative varus deformity had a greater tendency to go into valgus postoperatively.     

Radiographic Findings in Patients With Catastrophic Varus Collapse After Total Knee Arthroplasty

Background

Catastrophic varus collapse is an uncommon mechanism of failure in primary total knee arthroplasty (TKA). Varus collapse has been associated with obesity and smaller implant sizes. However, to our knowledge, preoperative radiographic characterization of this cohort has not been performed. Therefore, the following study evaluated preoperative alignment and how this correlates with the degree of eventual varus collapse identified in this patient population prior to revision.

Tibia Valga Morphology in Osteoarthritic Knees: Importance of Preoperative Full Limb Radiographs in Total Knee Arthroplasty

Osteoarthritis of the knee is associated with deformities of the lower limb. Tibia valga is a contributing factor to lower limb alignment in valgus knees. We evaluated 97 valgus knees and 100 varus knees. Long-leg films were taken in weight bearing with both knees in full extension. For valgus knees, 52 knees (53%) had a tibia valga deformity. Average tibia valgus deformation was 5.0°. For varus knees, there was only 1 case of tibia valga (1%), with a deformation of 2.5°. The aim of this study was to assess the prevalence of primary tibia valga in valgus and varus knees and understand how it affects our approach to total knee arthroplasty (TKA). We recommend having full-leg length films when planning for TKA in valgus knees.     

Risk factors of post-operative malalignment in fixed-bearing medial unicompartmental knee arthroplasty

Purpose

The purpose of this study was to identify risk factors of post-operative malalignment in medial unicompartmental knee arthroplasty (UKA) using multivariate logistic regression.

Methods

We retrospectively enrolled 92 patients who had 127 medial UKAs. According to post-operative limb mechanical axis (hip-knee-ankle [HKA] angle), 127 enrolled knees were sorted into acceptable alignment with HKA angle within the conventional?±?3 degree range from a neutral alignment (n?=?73) and outlier with HKA angle outside?±?3 degree range (n?=?54) groups. Multivariate logistic regression was used to analyse risk factors including age, gender, body mass index, thickness of polyethylene tibial insert, pre-operative HKA angle, distal femoral varus angle (DFVA), femoral bowing angle (FBA), tibial bone varus angle (TBVA), mechanical distal femoral and proximal tibial angles, varus and valgus stress angles, size of femoral and tibial osteophytes, and femoral and tibial component alignment angles.

Results

Pre-operative DFVA, TBVA and valgus stress angle were identified as significant risk factors. As DFVA increased by one degree, malalignment was about 45 times probable (adjusted OR 44.871, 95 % CI 2.608–771.904). Shift of TBVA and valgus stress angle to a more varus direction were also significant risk factors (adjusted OR 13.001, 95 % CI 1.754–96.376 and adjusted OR 2.669, 95 % CI 1.054–6.760).

Conclusions

Attention should be given to the possibility of post-operative malalignment during medial UKA in patients with a greater varus angle in pre-operative DFVA, TBVA and valgus stress angle, especially with a greater varus DFVA, which was the strongest predictor for malalignment.

     

Evaluating distal femoral torsion and posterior condylar line reliability for adjusting femoral component rotation in TKA,Egyptian population radiographic study

BackgroundFemoral component rotational alignment is critical for successful TKA. The primary study objective is to measure the preoperative distal femoral torsion (DFT) of an Egyptian patient’s cohort using a seated posteroanterior (PA) knee radiograph. The secondary objectives are to check the intraoperative reliability of using the posterior condylar line (PCL) as a reference for rotation and to measure postoperative component rotation using the same radiographic technique.Methods100 arthritic knees, 22 males, 78 females, 95 Varus and five valgus. A long anteroposterior radiograph [Hip to knee to ankle (HKA)] for coronal alignment assessment, and the anatomical posterior condylar angle (aPCA) between the anatomical transepicondylar axis (aTEA) and the PCL was measured in the seated PA knee radiographs for evaluating the DFT and component rotation. Intraoperative rotation was adjusted to 3° external rotation to the PCL.ResultsHKA improved from a preoperative mean 170.4° ± 6.2 to a postoperative mean 178.3° ± 1.5 (p < 0.005). DFT was internal in all knees; the mean aPCA was −4.5 ± 2.4 (0° to −9°), femoral component rotation significantly changed to a mean aPCA of −3.6 ± 2.3 (0° to −7°) (p = 0.005). Acceptable intraoperative patellar tracking in 94%, and patellar subluxation needed a lateral retinacular release in 2% (two valgus knees). The preoperative DFT was not affected by sex or direction of coronal deformity; more external DFT noticed in severe varus deformity.ConclusionsAll keens had an internal DFT not affected by sex, or coronal deformity direction. Using PCL as a guide to adjust femoral component rotation is a valid technique in our population.     

Does the Preoperative Varus Deformity Influence the Survival of Postoperative Neutral-Aligned TKAs? An Analysis With a Minimum 5-Year Follow-Up

Background

Postoperative neutral alignment may be an important factor for longevity of total knee arthroplasty (TKA). In knees with severe varus deformity, greater soft tissue release and bone resection were required to achieve neutral alignment. We investigated the relationship between the severity of preoperative varus deformity and longevity of neutral-aligned TKAs.

Potential errors in axial alignment using intramedullary instrumentation for total knee arthroplasty

Accurate restoration of normal limb alignment is crucial for the long-term survivorship of total knee arthroplasty (TKA). A mathematical model was used to evaluate the maximum error in varus and valgus alignment that could occur when cutting the tibia or femur during TKA using intramedullary (IM) guides of varying length and diameter. Minor deviations in the insertion point of IM instrumentation during TKA can result in malalignment of several degrees. This error can be minimized by careful attention to the entry point of the IM instrumentation or by increasing the IM rod diameter and length used during primary TKA.     

Effect of Total Knee Arthroplasty on Coronal Alignment of the Ankle Joint

BackgroundThe effect of total knee arthroplasty (TKA) on the ankle joint is not entirely clear. The purpose of this study is to assess postoperative changes in the coronal alignment of the ankle joint in patients undergoing TKA for various degrees of knee deformity.MethodsThis retrospective study included 107 patients who had undergone TKA for primary osteoarthritis. In all cases, preoperative coronal alignment deformity of the knee was corrected in an attempt to restore the native mechanical axis of the knee. Patients were stratified into 3 groups according to the degree of knee coronal alignment correction achieved intraoperatively: group 1 (<10° varus/valgus correction, n = 60), group 2 (≥10° varus correction, n = 30), and group 3 (≥10° valgus correction, n = 17). Knee/ankle alignment angles were measured on full-length, standing anteroposterior imaging preoperatively and postoperatively and included the following: hip-knee-ankle angle, tibial plafond inclination (TPI), talar inclination (TI), and tibiotalar tilt angle.ResultsSignificant changes in ankle alignment, specifically with regard to TPI (9.5° ± 6.9°, P < .01) and TI (8.8° ± 8.8°, P = .03) were noted in the ≥10° valgus correction group compared to the other 2 groups. Regardless of the degree of knee deformity correction, TKA did not lead to significant changes in the tibiotalar tilt angle.ConclusionA correction of ≥10° in a genu valgum deformity can affect ankle joint alignment, leading to alterations in TPI and TI. These findings need to be taken into consideration in assessing candidates for TKA as a possible cause of postoperative ankle pain.     

The UniSpacer™: correcting varus malalignment in medial gonarthrosis

While options for operative treatment of leg axis varus malalignment in patients with medial gonarthrosis include several established procedures, such as unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA) or high tibial osteotomy (HTO), there has been little focus on a less invasive option introduced more recently: the UniSpacer™ implant, a self-centering, metallic interpositional device for the knee. This study evaluates clinical and radiological results of the UniSpacer™, whether alignment correction can be achieved by UniSpacer™ arthroplasty and alignment change in the first five postoperative years. Anteroposterior long leg stance radiographs of 20 legs were digitally analysed to assess alignment change: two relevant angles and the deviation of the mechanical axis of the leg were analysed before and after surgery. Additionally, the change of the postoperative alignment was determined one and five years postoperatively. Analysing the mechanical tibiofemoral angle, a significant leg axis correction was achieved, with a mean valgus change of 4.7 ± 1.9°; a varus change occurred in the first postoperative year, while there was no significant further change of alignment seen five years after surgery. The UniSpacer™ corrects malalignment in patients with medial gonarthrosis; however, a likely postoperative change in alignment due to implant adaptation to the joint must be considered before implantation. Our results show that good clinical and functional results can be achieved after UniSpacer™ arthroplasty. However, four of 19 knees had to be revised to a TKA or UKA due to persistent pain, which is an unacceptably high revision rate when looking at the alternative treatment options of medial osteoarthritis of the knee.     

The Impact of Coronal Alignment on Revision in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty

BackgroundTo better define the optimal alignment target for medial fixed-bearing unicompartmental knee arthroplasty (UKA), this study compares the postoperative mechanical alignment of well-functioning UKAs against 2 groups of failed UKAs, including revisions for progression of lateral compartment osteoarthritis (“Progression”) and revisions for aseptic loosening or subsidence (“Loosening”).MethodsFrom our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000, we identified 37 UKAs revised for Progression and 61 UKAs revised for Loosening. Each of these revision cohorts was matched based on age at surgery, gender, body mass index, and postoperative range of motion with unrevised UKAs that had at least 10 years of follow-up and a Knee Society Score of 70 or greater without subtracting points for alignment (“Success” groups). Postoperative alignment was quantified by the hip-knee-ankle (HKA) angle measured on long-leg alignment radiographs.ResultsThe mean HKA angle at 4-month follow-up for the Progression group was 0.3° ± 3.6° of valgus compared to 4.4° ± 2.6° of varus for the matched Success group (P < 0.001). For the Loosening group, the mean HKA angle was 6.1° ± 3.1° of varus versus 4.0° ± 2.7° of varus for the matched Success group (P < 0.001).ConclusionsPatients with well-functioning UKAs at 10 years exhibited mild varus mechanical alignment of approximately 4°, whereas patients revised for progression of osteoarthritis averaged more valgus and those revised for loosening or subsidence averaged more varus. The optimal mechanical alignment for medial fixed-bearing UKA survival with contemporary polyethylene is likely slight varus.