人工智能三维术前规划在全髋关节置换术中的应用和准确性分析

目的 探讨人工智能三维规划系统在全髋关节置换术中假体型号选择的准确性。方法 选取2019年11月至2020年12月住院期间的27例（32髋）行初次全髋关节置换手术患者，其中男10例，女17例。术前完成患侧髋关节X线及CT影像资料采集，分别使用传统模板测量法和人工智能三维术前规划进行假体型号预测，通过与全髋关节置换术中实际所用型号进行对比，比较两种预测方法的吻合率。结果 人工智能三维术前规划对髋臼及股骨假体型号预测的吻合率分别为90.6%和81.3%，传统模板测量对髋臼及股骨假体型号预测的吻合率分别为56.3%和46.9%。两种预测方法吻合率比较，差异有统计学意义（P<0.05）。人工智能三维规划系统预测髋臼杯型号同实际应用型号之间存在相关性（r=0.915，P<0.001），人工智能三维规划系统预测股骨假体型号同实际应用型号之间存在相关性（r=0.941，P<0.001）。结论 人工智能三维术前规划系统较传统模板测量方法更能准确预测假体型号。     

Orthosize软件在初次全髋关节置换术前测量的准确性和可靠性分析

目的 回顾性研究Orthosize软件在初次全髋关节置换（THA）术前测量的准确性及可靠性,探讨THA术前设计的必要性和重要性。方法 收集2018年1月至2020年12月荆门市中医医院符合要求的行THA的患者共63例作为研究对象。其中,男26例,女37例;年龄48 ～ 76岁,平均（64.86±7.16）岁。两个测量者均使用传统胶片模板（胶片测量法）及Orthosize软件（软件测量法）预测假体大小,记录术前测量的髋臼及股骨柄假体型号、术后测量X线假体型号。计算两种方法术前、术后测量的准确率,对比分析两种方法术前预测假体型号与实际使用型号的差异性,并且评估Orthosize软件测量法的可靠性。结果 术前预测假体型号的准确率如下：在髋臼侧胶片测量法与软件测量法相差1个型号以内分别占87.3%、95.2%（完全符合分别占60.3%、73.0%）,在股骨侧胶片测量法与软件测量法相差1个型号以内分别占90.5%、96.8%（完全符合分别占65.1%、76.2%）,两种方法术前测量的差异性比较有统计学意义（P＜0.05）,且软件测量法在髋臼侧和股骨侧均较胶片测量法准确率高。软件测量法组内及组间测量数据的可靠性良好（Kappa＞0.81）。结论 Orthosize软件在THA术前设计中预测假体型号的准确性和可靠性令人满意,准确的术前测量对于髋关节的解剖重建和功能恢复具有重要的意义。     

CR假体与PS假体全膝关节置换治疗膝骨性关节炎合并膝外翻畸形的疗效分析

目的 比较后交叉韧带保留型（CR）假体与后方稳定型（PS）假体行人工全膝关节置换术（TKA）治疗膝骨性关节炎合并膝外翻畸形的临床疗效。方法 回顾性分析南昌大学附属赣州医院关节外科2019年5月至2021年5月收治的60例（60膝）膝骨性关节炎合并膝外翻畸形患者资料,均为单侧置换。30例采用CR假体行TKA治疗（CR组）,30例采用PS假体行TKA治疗（PS组）。比较两组患者的手术时间、术中失血量、术后引流量、术后3 d血红蛋白（Hb）下降量及深静脉血栓发生情况;比较两组患者手术前后膝外翻角;比较两组患者术后1周、1个月、3个月、6个月、1年疼痛视觉模拟评分（VAS）、膝关节活动度（ROM）、美国特种外科医院膝关节评分（HSS）。结果 60例患者均顺利完成TKA手术,所有患者随访13 ～ 28个月,平均（18.51±0.90）个月。CR组术中出血量、术后引流量、术后3 d的Hb下降量较PS组减少（P＜0.05）;两组手术时间相当、术后均无深静脉血栓发生,差异无统计学意义（P＞0.05）;两组手术前后膝外翻角的比较差异无统计学意义（P＞0.05）;CR组术后1周、1个月VAS评分较PS组更低（P＜0.05）,两组术后3个月、6月、1年VAS评分比较差异无统计学意义（P＞0.05）;CR组术后1周、1个月、3个月膝关节ROM和HSS评分优于PS组（P＜0.05）,两组术后6个月、1年膝关节ROM和HSS评分比较差异无统计学意义（P＞0.05）。结论 采用CR或PS假体行TKA手术治疗膝骨性关节炎合并膝外翻畸形均可有效纠正膝关节畸形、减轻膝关节疼痛、改善膝关节活动度及功能,取得满意临床疗效;但相对PS假体,CR假体保留了后交叉韧带,减少了股骨髁部截骨量,从而减少手术出血,更好减轻早期术后疼痛,有助于TKA术后早期功能康复。     

股骨近端防旋髓内钉治疗外侧壁破裂和未破裂股骨转子间骨折的疗效比较

目的 探讨股骨近端防旋髓内钉（PFNA）治疗外侧壁破裂和未破裂股骨转子间骨折的疗效。方法 回顾性分析2016年1月至2019年12月上海市浦东新区人民医院采用PFNA治疗的118例股骨转子间骨折的患者资料,其中外侧壁破裂组42例,外侧壁未破裂组76例。比较两组患者的手术时间、术中出血量、术中透视次数、术中骨折复位质量、术后尖顶距、术后下床活动时间、术后完全负重时间、骨折愈合时间、术后并发症、末次随访时髋关节屈伸活动度（ROM）及Harris评分。结果 118例患者随访12 ～ 36个月,平均（16.2±4.9）个月。两组患者的手术时间、术中出血量、术中骨折复位质量、术后尖顶距比较,差异无统计学意义（P＞0.05）;外侧壁破裂组术中透视次数、术后下床活动时间、术后完全负重时间、骨折愈合时间明显劣于外侧壁未破裂组,差异有统计学意义（P＜0.05）。外侧壁破裂组有8例（19.0%）发生骨折延迟愈合,外侧壁未破裂组有3例（3.9%）发生骨折延迟愈合,差异有统计学意义（P＜0.05）。外侧壁破裂组内固定失效发生率为7.1%,外侧壁未破裂组为6.6%,差异无统计学意义（P＞0.05）。末次随访时外侧壁未破裂组髋关节屈伸活动度及Harris评分均优于外侧壁破裂组（P＜0.05）,其中外侧壁破裂组Harris评分优良率为78.6%,外侧壁未破裂组为94.7%,差异有统计学意义（P＜0.05）。结论 应用PFNA治疗外侧壁破裂和未破裂股骨转子间骨折可取得满意效果,但外侧壁破裂组的疗效劣于外侧壁未破裂组,应重视外侧壁破裂型股骨转子间骨折的治疗,防止内固定失效。     

术中应用不同假体对全膝关节置换术后引流的影响

目的 探讨术中使用后方稳定型（posterior cruciate stabilization, PS）与后交叉韧带保留型（posterior cruciate retention, CR）假体对全膝关节置换术（total knee arthroplasty, TKA）术后引流的影响。方法 回顾性分析2018年6月至2018年10月终末期骨性关节炎行全膝关节置换的患者102例，其中62例采用后交叉韧带保留型（CR）假体（CR组），40例采用后稳定型（PS）假体（PS组）。所有患者术中均使用止血带、关节腔注射氨甲环酸（tranexamic acid, TXA），术后患肢屈曲1 h、引流管夹毕1 h、患肢冰敷24 h。收集术后2、4、24、48 h引流量和引流液中血红蛋白（hemoglobin, HB）含量，以及术后2、24、48 h静脉血中的血红蛋白（HB）含量。统计术后输血情况、早期感染并发症例数。结果 102例患者随访3个月，术后总引流量CR组（292.9±128.3）mL比PS组引流量为（355.2±136.8）mL少，两组比较差异有统计学意义（P＜0.05）。术后1 d的CR组的引流量比PS组少，两组比较差异有统计学意义（P＜0.05）。术后24 h的CR组引流液中血红蛋白含量比PS组明显下降，两组比较差异有统计学意义（P＜0.05）。术后24、48 h的PS组静脉血中血红蛋白含量比CR组明显下降，两组比较差异有统计学意义（P＜0.05）。CR组2例输了2 U红细胞，PS组2例输了1 U红细胞、9例输了2 U红细胞。102例患者术后早期均未出现感染并发症。结论 与PS假体相比，采用CR假体可减少患者的失血量、术后引流量少、降低全膝关节置换术后贫血的发生、减少围术期输血率。     

小切口微创治疗难复型股骨转子间骨折的疗效观察

目的 探讨髋部前外侧小切口手术入路复位方式利用PFNA内固定治疗难复型股骨转子间骨折患者的临床疗效。方法 选取2017年5月至2021年5月湖南省湘西自治州人民医院的老年难复型股骨转子间骨折患者共34例,其中髋部前外侧小切口组19例（行髋部前外侧小切口PFNA内固定手术）,常规外侧大切口组15例（行常规外侧大切口PFNA内固定手术）。比较两组患者的手术时间、切口长度、术中出血量、早期下床活动时间、术后疼痛评分等相关数据。结果 所有患者均获得随访6 ～ 10个月,平均随访（8.12±1.64）个月。髋部前外侧小切口组患者的手术时间、术中出血量、手术切口长度、早期下床活动时间、术后疼痛评分优于常规外侧大切口组,两组间比较差异有统计学意义（P＜0.05）。结论 对于老年难复型股骨转子间骨折患者,髋部前外侧微创切口PFNA手术治疗难复位型股骨转子间骨折的方式术中出血量少,手术创伤小,患者的术后疼痛低,术后下床活动时间早,安全性大大提高。     

基于国人172例Oxford 3代单髁膝关节置换术探索手术器械配套规律

回顾分析172例单髁膝关节置换（UKA）手术患者的临床特征、手术工具及植入假体的型号,为围手术期医护人员在手术前准备手术器械及假体提供参考。根据研究结果,专科手术小组优化了手术器械包的配套：在股骨成型工具常规包中,男性患者配型号S、M,备用包配型号XS、L;女性患者常规包配股骨的型号XS、S,备用包配型号M、L。胫骨成...     

全髋关节置换前假体型号的选择方法CSCD

背景:假体和股骨近段髓腔横断面的匹配非常重要,模板测量法术前预测股骨假体型号准确率低,因此有必要寻找新的方法用于全髋关节置换前预测假体型号。目的:利用CT测量股骨峡部最小髓腔内径及股骨颈髓腔内侧径,并通过两种髓腔径大小术前选择股骨假体型号。方法:利用CT测量52例61髋初次全髋关节置换患者置换前股骨颈髓腔内侧径和峡部最小髓腔内径大小,根据两种髓腔的大小进行术前选择股骨假体型号;以常规模板测量法作为对照。分析两种方法术前选择股骨假体型号的可行性、准确性。结果与结论:股骨颈髓腔内侧径和峡部最小髓腔内径大小与股骨假体型号之间都存在很强的相关性(r=0.97-0.99,P<0.05)。CT峡部测量法术前选择股骨假体型号的优秀率为47.5%;比模板测量法有更好准确性,尤其是在≤65岁的年龄段。股骨颈内侧径测量法置换前选择股骨假体型号优秀率为52.5%;比模板测量法有更好准确性,尤其在>45岁的年龄段。CT峡部测量法对于年龄≤65岁或股骨干髓腔窄小者有较好临床应用价值。股骨颈内侧径测量法则在年龄>45岁或股骨干髓腔宽大者的置换前选择假体型号方面具有更好的准确性。两种方法综合运用有利于选择出匹配度更高的股骨假体。     

膝关节置换术后长期胫骨近端力学性能的预测

目的 分 析 膝 关 节 单 髁 置 换 术 ( unicompartmental knee arthroplasty, UKA) 和 全 膝 置 换 术 ( total knee arthroplasty, TKA)后长期胫骨近端力学性能的变化,探究 UKA 和 TKA 的失效原因。 方法 建立健康、UKA、TKA胫骨近端有限元模型,利用 Wolff 骨重建理论结合有限元法预测胫骨近端的密度分布和应力分布。 结果 UKA 外侧踝平均应力基本不变,但呈增大趋势,平均密度增加 2%,内侧踝平均密度减小 13%,平均应力均减少 11%。 TKA外侧踝平均密度减少 1. 5%,平均应力减少 14%,内侧踝平均密度减少 1. 4%,平均应力减少 19%,假体末端平均密度增加 10%,平均应力增加 15%。 结论 UKA、TKA 假体的植入会造成应力遮挡现象,可能是产生术后假体松动的主要原因。 TKA 假体末端应力增大,可能导致 TKA 的失效。 UKA 非置换侧平均应力随着骨重建的进行不断增大,可能就导致 UKA 中远期对侧骨关节炎恶化。 研究结果可以为降低 UKA、TKA 并发症发生概率提供数据支持。     

HSS膝关节康复方案对单髁置换术后早期关节功能和步态的影响

目的 研究美国特种外科医院（hospital for special surgery, HSS）膝关节康复方案对膝关节单髁置换术（unicompartmental knee arthroplasty, UKA）术后关节功能及步态的近期影响。方法 回顾性分析2018年1月至2021年6月间在湖北省中医院行UKA术的60例患者。将采用HSS膝关节成形术康复指南进行康复治疗的30例患者作为HSS组;将同期采用常规康复方案的30例患者作为常规组。记录术后1周、3个月、6个月、1年两组患者的膝关节活动范围（range of motion, ROM）、美国特种外科医院膝关节HSS评分、人工关节遗忘指数（forgotten joint index, FJS）。分别于术后6个月、1年时采用GaitWatch三维步态分析及运动训练系统进行步态信息数据的采集,并比较两组间差异。结果 两组均完成术后1年以上随访,膝关节功能比较：术后3个月随访,HSS组膝关节ROM、HSS评分高于常规组,差异有统计学意义（P＜0.05）;术后6个月随访,HSS组患者膝关节ROM、HSS评分高于常规组,FJS评分低于常规组,差异有统计学意义（P＜0.05）;术后1年随访,HSS组的HSS评分高于常规组、FJS评分低于常规组,差异有统计学意义（P＜0.05）。步态参数比较：术后6个月随访,HSS组的步数、步长及单足支撑相较常规组高,差异有统计学意义（P＜0.05）;术后1年随访,HSS组的步数、步频、单足支撑相较常规组高,差异有统计学意义（P＜0.05）。结论 HSS膝关节成形术后康复方案在UKA术后早期可显著改善膝关节功能和步态,有利于UKA术后早期康复。     

Improvement of femoral component size prediction using a C-arm intensifier guide and our established algorithm in unicompartmental knee arthroplasty: A report from a Chinese population

BackgroundUnicompartmental knee arthroplasty (UKA) is becoming more widely used with the recent increase in popularity of the use of minimally invasive techniques. However, it is difficult to judge about the femoral component size in UKA using preoperative templating digitally or otherwise. Even when using navigation it is impossible to control the femoral component size. The aim of this study is to develop a better pre- or intra-operative measure that will predict femoral component size.MethodsNinety-two UKA cases were studied from June 2007 to December 2011 with a mean 26-month follow-up. We developed an intra-operative C-arm intensifier guide (CAIG) method for determining femoral size instead of pre-operative templating. The accuracy of prediction of both methods was compared from a review of post-operative radiographs. In addition, we summarized all cases and developed a Chinese algorithm to determine the femoral component size pre-operatively.ResultsThere was a significant difference between templating (59%) and CAIG (92%) method (P = 0.0001). In the Chinese algorithm, height based on gender and tibial size both have greater accuracy of prediction (88% and 70.7%) than the Oxford algorithm (51.1% and 59.8%). Component size distribution and optimal tibial/femoral pairing differed from those in the Oxford report.ConclusionsWe conclude that the Chinese algorithm can greatly improve the accuracy of prediction of femoral component size. In addition, CAIG-assisted implantation of a UKR is a reliable intra-operative tool and can aid size selection of the femoral component.Level of EvidenceLevel III.     

Determination of femoral component size in unicompartmental knee replacement

It is difficult to determine the ideal size of femoral component when a unicompartmental knee replacement (UKR) is implanted with a minimally invasive approach. The aim of the study was to identify the best method of determining femoral component size pre-operatively. This was done by assessing the accuracy with which it could be predicted by pre-operative templating, patient height, gender and tibial component size. One hundred patients who had had Oxford UKR were studied. Pre-operative radiographs were templated and patient height, gender and implanted tibial component size were recorded. From a review of post-operative radiographs and the known size of component used the ideal size of component that should have been used was established. By relating patient height, gender and tibial component size to the ideal femoral component size the range of these various parameters that best predicted each component size was identified. The reliability of these predictions was assessed assuming that a component one size off ideal was acceptable and two sizes off was unacceptable. Templating was correct in 67% of cases, acceptable in 33% and was never unacceptable. Height alone was correct in 56%, acceptable in 38% and unacceptable in 6%. Height based on gender was correct in 75%, acceptable in 25% and was never unacceptable. Tibial size was correct in 56%, acceptable in 41% and unacceptable in 3%. We conclude that both templating and height based on gender are reliable methods of assessing femoral component size. However because errors can occur surgeons are advised to use both.     

Differences in impact on adjacent compartments in medial unicompartmental knee arthroplasty versus high tibial osteotomy with identical valgus alignment

BackgroundIt is unclear why medial unicompartmental knee arthroplasty (UKA) with postoperative valgus alignment causes adjacent compartment osteoarthritis more often than high tibial osteotomy (HTO) for moderate medial osteoarthritis of the knee with varus deformity. This study used a computer simulation to evaluate differences in knee conditions between UKA and HTO with identical valgus alignment.MethodsDynamic musculoskeletal computer analyses of gait were performed. The hip–knee–ankle angle in fixed-bearing UKA was changed from neutral to 7° valgus by changing the tibial insert thickness. The hip–knee–ankle angle in open-wedge HTO was also changed from neutral to 7° valgus by opening the osteotomy gap.ResultsThe lateral tibiofemoral contact forces in HTO were larger than those in UKA until moderate valgus alignments. However, the impact of valgus alignment on increasing lateral forces was more pronounced in UKA, which ultimately demonstrated a larger lateral force than HTO. Valgus alignment in UKA caused progressive ligamentous tightness, including that of the anterior cruciate ligament, resulting in compression of the lateral tibiofemoral compartment. Simultaneously, patellofemoral shear forces were slightly increased and excessive external femoral rotation against the tibia occurred due to the flat medial tibial insert surface and decreased lateral compartment congruency. By contrast, only lateral femoral slide against the tibia occurred in excessively valgus-aligned HTO.ConclusionsIn contrast to extra-articular correction in HTO, which results from opening the osteotomy gap, intra-articular valgus correction in UKA with thicker tibial inserts caused progressive ligamentous tightness and kinematic abnormalities, resulting in early osteoarthritis progression into adjacent compartments.     

External rotation of the tibial component should be avoided in lateral unicompartmental knee arthroplasty

BackgroundLateral unicompartmental knee arthroplasty (UKA) leads to good clinical outcomes for isolated lateral osteoarthritis. However, the impact of the tibial component position on postoperative outcomes in lateral UKA is yet to be determined.PurposeThis study investigated the influence of tibial component malposition on clinical outcomes in lateral UKA.MaterialsThis was a retrospective study of 50 knees (mean age 73.5 years) who underwent lateral UKA between September 2013 and January 2019. The Oxford Knee Score (OKS), Knee Society Score – Knee (KSSK), and Knee Society Score – Function (KSSF) were evaluated. The coronal alignment, posterior slope of tibial component, tibial component rotation relative to Akagi’s line (angle α), and femoral anteroposterior (AP) axis (angle β) were measured postoperatively. The average follow up period was 2.3 (range, 1–4.9) years.ResultsClinical scores were significantly improved after lateral UKA. The mean coronal alignment was 0.9° ± 3.2° varus (range, 9.1° varus to 5.5° valgus), the mean posterior slope was 6.8° ± 3.8° (range, 0.8° to 14.8°). The mean α and β angles, were 4.1° ± 5.8° (range, −9.7° to 16.5°) and 6.7° ± 7.1° (range, −7.0° to 20.5°) external rotation. The angle α had significant negative correlations with postoperative OKS (r = −0.36), KSSK (r = −0.28), and KSSF (r = −0.39), and angle β had significant negative correlations with postoperative OKS (r = −0.34) and KSSK (r = −0.46).ConclusionExcessive external rotation of the tibial component could negatively influence the postoperative outcomes of lateral UKA.     

Periprosthetic bone mineral density changes after unicondylar knee arthroplasty

BackgroundUnicompartmental knee arthroplasty (UKA) has received renewed interest in the last decade. UKA involves minor injury to soft tissues, limited removal of bone and delicate preservation of knee anatomy and geometry. In theory, UKA provides an opportunity to restore post-surgical knee kinematics to near normal.HypothesisUKA leaves patellofemoral joint free to meet high mechanical forces with no stress-shielding and therefore might preserve bone mineral density (BMD).Patients and methodsWe studied 21 patients with osteoarthritis(OA), who had received medial compartment UKA at Kuopio University Hospital between October 1997 and September 2000. BMD was measured by dual-energy X-ray absorptiometry (DEXA), at baseline (within a week after surgery) and at intervals until 7 years.ResultsDEXA results were reproducible. The highest rate of periprosthetic bone loss occurred during the first 3 months after UKA. The average loss in BMD was 4.4% (p = 0.039) in the femoral diaphysis and it ranged from 11.2% (p < 0.001) to 11.9% (p = 0.002) in the distal femoral metaphysis; however, BMD changes in these regions, from 2 years to 7 years, were nonsignificant. At the 1-year follow-up, the BMD of the medial tibial metaphysis had increased by 8.9% (p = 0.02), whereas those in the lateral tibial metaphysial (–2.4%) and diaphysial regions (–2.0%) did not change significantly.InterpretationsUKA did not preserve periprosthetic BMD in the distal femoral metaphysis, whereas BMD changes in the tibial metaphysis were minor, consistent with a mechanical balance between the medial and lateral tibial compartments.Level of Evidence 2bProspective case control study.     

Femorotibial rotational mismatch of the Oxford unicompartmental knee in the flexion position is a risk for poor outcomes

BackgroundFemorotibial rotational mismatch has been reported to cause unsatisfactory outcomes after total knee arthroplasty. However, to our knowledge, no previous reports have described the relationship between the femorotibial rotational mismatch and clinical outcomes of Oxford unicompartmental knee arthroplasty (UKA).MethodsIn total, we studied 52 knees with primary varus knee osteoarthritis that underwent Oxford UKA with a navigation system. Tibial component internal rotation angles relative to the femoral component at extension and flexion angle of 90° were measured using a navigation system. We evaluated the relationship between the clinical outcomes and femorotibial rotational mismatch angles. Additionally, we evaluated the relationships between the outcomes and rotational alignments of the femur and tibial components measured by computed tomography (CT).ResultsThe tibial component internal rotational angle relative to the femoral component was significantly larger at a flexion angle of 90° than on extension (P < .001) and showed negative correlations with the Knee Society Functional Score and the pain and sports subscales of the Knee Injury and Osteoarthritis Outcome Score. Rotational alignment of the femur and tibial components on computed tomography was not associated with clinical outcomes.ConclusionThe tibial component internal rotational angle relative to the femoral component in the flexion position was negatively correlated with clinical outcome. Surgeons should pay attention to a rotational mismatch between components in the flexion position during the Oxford UKA procedure. Navigation systems will be effective in reducing the femorotibial rotational mismatch and improving clinical outcomes.     

Rotational alignment errors can occur in unicompartmental knee arthroplasty if anatomical landmarks are misused: A preoperative CT scan analysis

BackgroundAccurate implant positioning, including rotation, is essential for successful unicompartmental knee arthroplasty (UKA). This study defined the rotational error that would result in medial UKA when using the medial edge of the tibial tubercle (TT) rather than the medial tibial spine for determining tibial component rotation, and in lateral UKA when aligning the anterior edge of the sagittal tibial cut with the lateral edge of the patellar tendon.MethodsPreoperative computed tomography (CT) scans were reviewed in 88 knees undergoing medial (n = 71) and lateral (n = 17) UKAs. In medial UKA, the angle between a line along the long axis of the medial tibial spine and a line drawn to the medial edge of the TT was measured. In lateral UKA, the angular relationship between the longitudinal axis of the lateral tibial spine and the lateral edge of the patellar tendon was measured.ResultsIn medial UKA, an average angular error of 9.6° of external rotation could result if the medial edge of the TT is used to set tibial implant rotation. In lateral UKA, the error of the sagittal tibial cut was an average of 7.1° of excessive external rotation if it is referenced on the lateral edge of the patellar tendon.ConclusionsThe preoperative CT scan analysis showed that using the medial edge of the TT and lateral edge of the patellar tendon to set tibial implant rotation may result in excessive external rotation in medial and lateral UKAs, which could result in kinematic mismatch, suboptimal contact areas and rotational malalignment.     

The effect of component alignment on clinical outcomes in fixed bearing unicompartmental knee arthroplasty

BackgroundThe aim of this study is to report component alignment in a series of ZUK fixed bearing unicompartmental knee arthroplasty (UKA) implants and compare this to clinical outcomes.MethodsThe radiographs, Knee Society Scores (KSS) and knee flexion of 223 medial UKAs were evaluated. The following alignment parameters were assessed; coronal and sagittal femoral component angle (c-FCA and s-FCA), coronal and sagittal tibia component angle (c-TCA and s-TCA) and the coronal tibiofemoral angle (c-TFA). Each alignment parameter was grouped at consecutive 2.5° intervals, mean KSS and knee flexion was then compared between the interval groups.Results96.4% of femoral components were between 7.5° of varus and valgus and 95.1% between 7.5° extension and 5° flexion. 89.6% of tibial components were between 7.5° of varus and 2.5° valgus and 97.3% between 2.5° and 15° flexion. There was no significant difference between the KSS or knee flexion between any of the incremental groups of component alignment. Mean c-TFA was 0.2 ± 3.0°, 92.4% were between −5° (varus) and 5° (valgus). KSS were significantly greater for two of the increments with slightly more varus. Linear regression analysis showed there was very weak correlation (R² = 0.1933) between c-TFA and c-TCA.ConclusionsThe results of this study show that fixed bearing UKA components are forgiving to accommodate some variation in tibial and femoral component position without effecting clinical outcome scores or knee flexion. Limb alignment matters more than component position and knees with slight varus tibiofemoral alignment have better clinical scores than those with valgus.     

Fixed bearing lateral unicompartmental knee arthroplasty—Short to midterm survivorship and knee scores for 101 prostheses

BackgroundIsolated unicompartmental knee arthritis is less common laterally than medially. Lateral unicompartmental knee arthroplasty (UKA) constitutes only 1% of all knee arthroplasty performed. Use of medial UKA is supported by several published series showing good long-term survivorship and patient satisfaction, in large patient cohorts. Results of lateral UKA however have been mixed. We present the short and mid-term survivorship and 5-year clinical outcome of 101 lateral UKAs using a single prosthesis.MethodsOver a 9 year period, 100 patients who satisfied inclusion criteria underwent a lateral fixed-bearing unicompartmental arthroplasty. American Knee Society (AKSS), Oxford Knee (OKS) and modified Western Ontario McMaster Universities Arthritis Index (WOMAC) scores were completed preoperatively and at 1, 2 and 5 years postoperatively. Kaplan–Meier survival analysis was used to determine the 2-year and 5-year survivorship, using revision for any cause as end point.ResultsSurvivorship was 98.7% and 95.5% at 2 and 5 years respectively. 1 knee was revised for subsidence of the tibial component and 1 knee for progression of medial compartment osteoarthritis. Of a possible 35 knees in situ at 5 year follow-up, 33 knees were fully scored. Median AKSS, OKS and modified WOMAC scores were 182, 41, and 16 respectively.ConclusionsThe mid-term survivorship and outcome scores at 5-years suggest that lateral unicompartmental knee arthroplasty provides a valuable alternative to total joint replacement in selected patients with isolated lateral tibio-femoral arthritis at mid-term follow-up.Level II evidence.     

单髁置换术应用于骨关节炎合并前交叉韧带缺失的三维有限元研究

目的采用有限元方法比较前交叉韧带(anterior cruciate ligament,ACL)完整与缺失的骨关节炎患者单髁关节置换(unicompartmental knee arthroplasty,UKA)术后膝关节生物力学特性,分析ACL缺失对膝关节单髁置换术后的运动和应力的影响。方法根据膝关节CT、MRI图像,建立有限元模型。采用逆向工程技术重建活动衬垫单髁假体,加载入该正常膝关节三维有限元模型。在不同屈膝角度(0°、30°、60°、90°、120°)加载载荷,观察在ACL完整(ACL-intact,ACLI)和缺失(ACL-deficiency,ACLD)情况下,膝关节的最大接触压和位移程度。结果 UKA-ACLI与UKA-ACLD模型在膝关节屈膝各角度,各部位(外侧股骨软骨、胫骨软骨、半月板、股骨假体、胫骨假体、衬垫)最大应力无明显差异,ACLD模型在膝关节屈膝0°和30°位前后位移明显大于ACLI模型,在膝关节屈膝0°位股骨相对内旋减小,在膝关节屈膝30°位股骨相对外旋增加。结论标准位置假体植入情况下,ACL缺失并不会导致UKA术后应力异常增大,会导致在膝关节伸直位时位移增加。