Patellar tracking during simulated quadriceps contraction

The current study compared patella tracking during simulated concentric and eccentric quadriceps contractions in 12 knees from cadavers using a three-dimensional electromagnetic tracking system. The patella shifted (translated) and tilted medially during approximately the initial 22 degrees tibiofemoral flexion. The patella then shifted and tilted laterally for the remaining arc of tibiofemoral flexion (90 degrees). At 90 degrees tibiofemoral flexion, the patella had an orientation of lateral patella shift and lateral patella tilt. Patella shift was significantly more lateral between 40 degrees and 70 degrees tibiofemoral flexion during concentric quadriceps action than during eccentric contraction. Patella tilt was significantly more lateral between 45 degrees and 55 degrees tibiofemoral flexion during concentric quadriceps contraction than during eccentric action. No other significant differences were seen between the quadriceps contraction conditions. The current study supports the hypothesis that patellar instability is most likely a result of various anatomic and physiologic factors causing a failure of the extensor mechanism to deliver the patella into the femoral sulcus and that a patellar dislocation rarely would occur in a normal knee.     

内侧髌股韧带重建术中应用止血带对髌骨轨迹的影响

背景：内侧髌股韧带（MPFL）是限制髌骨向外侧脱位的主要静力稳定结构,MPFL重建术成为治疗髌骨不稳的主要选择。术中止血带的应用对减少出血量,改善手术视野提供了重要保障,同时也不可避免改变了股四头肌的张力,然而对于髌骨轨迹是否产生明显影响一直未有明确定论。目的：比较MPFL重建术中应用止血带对髌骨轨迹的影响。方法：2008年3月至2011年2月行双束解剖重建MPFL的髌骨复发性脱位患者53例（66膝）,男23例（28膝）,女30例（38膝）;年龄18-34岁,平均26岁。发病至手术时间1个月-13年,其中44例有明显外伤致髌骨脱位史。术中观察止血带充气前、后对髌骨轨迹的影响,以及是否需行外侧支持带松解。结果：53例（66膝）中,止血带未充气时,判断需行外侧支持带松解者5膝（5/66）;止血带充气后,判断需行外侧支持带松解者6膝（6/66）,两者比较无统计学差异（P〉0.05）。重建MPFL后再次应用止血带观察,当止血带充气时,66膝髌骨轨迹良好;当止血带放松后,2膝出现髌骨内移（2/66）,两者比较无统计学差异（P〉0.05）。结论：使用止血带前、后对髌骨轨迹无明显影响,术中观察髌骨轨迹良好则无需行外侧支持带松解。     

Long-term changes of the nonresurfaced patella after total knee arthroplasty

BACKGROUND: The most common complications of total knee arthroplasty involve the patellofemoral joint. However, the long-term fate of the nonresurfaced patella after total knee arthroplasty has seldom been reported. The purpose of this study was to evaluate the long-term changes of the nonresurfaced patella after total knee arthroplasty. METHODS: We retrospectively evaluated the nonresurfaced patella in 227 knees (181 patients) at an average of 8.5 years after total knee arthroplasty. Functional results were correlated with radiographic changes, and risk factors leading to abnormal changes of the patella were analyzed. RESULTS: Preoperatively, 186 (82%) of the patellae tracked centrally, thirty-nine (17%) displaced or tilted laterally, and two (1%) subluxated laterally. At the time of the latest follow-up, 133 (59%) of the patellae still tracked centrally with preservation of the cartilage thickness, fifteen (7%) showed early lateral tilt, sixty-eight (30%) had progressive loss of lateral cartilage thickness with lateral tilt and/or displacement, seven (3%) had progressed to lateral subluxation, and four (2%) tilted medially. An abnormal patellofemoral joint did not affect the knee and functional scores (p = 0.90 and 0.89, respectively). However, symptoms such as difficulty rising from a chair or reluctance to use the involved lower limb while climbing stairs were noted. Preoperative patellar maltracking was identified as the only risk factor leading to postoperative patellar abnormalities (relative risk, 2.7; 95% confidence interval, 2.21 to 3.30; p = 0.003). CONCLUSIONS: At the time of follow-up, at an average of 8.5 years, patellar tracking and the patellofemoral joint remained normal after approximately 60% of the total knee arthroplasties performed without resurfacing of the patella. Progressive degenerative changes of the nonresurfaced patella (mainly on the lateral facet) and patellar maltracking were the most common abnormal radiographic changes. Patients with preoperative patellar maltracking were at risk for the development of these changes and clinical symptoms. Resurfacing of the patella during total knee arthroplasty may benefit such patients.     

复合软组织手术对儿童习惯性髌骨脱位髌股关节适应性的影响

目的 研究复合软组织手术治疗不同年龄段儿童习惯性髌骨脱位后,髌股关节适应性的变化情况.方法 回顾性分析2000至2007年收治的习惯性髌骨脱位患儿73例.男24例,女49例;平均年龄7.1岁(3～15岁);单侧47例,双侧26例.按照年龄分为A、B两组:A组年龄3～8岁(包括8岁),24例(30膝);B组年龄8～15岁,49例(69膝).复合软组织手术包括膝关节外侧充分松解、内侧紧缩、髌腱半腱上点移位(Roux-Goldthwait手术)和股内侧肌止点下移术.术前及随访中分别行髌骨轴位和侧位X线检查,测量股骨滑车角、髌骨高度、髌骨-滑车适配角及髌骨倾斜角(Laurin角)的变化情况,以评价髌股关节适应性.结果 73例患儿均获随访,平均随访38个月(25～98个月).末次随访时髌骨脱位均无复发,其中2例发生髌骨内侧脱位.股骨滑车角:A组由术前的150.1°±5.1°改善为144.3°±6.0°,手术前后差异有统计学意义(P＜0.05);B组手术前后差异无统计学意义(P＞0.05).其余测量指标在两组均无显著变化.结论 复合软组织手术对儿童习惯性髌骨脱位髌股关节的塑型有影响,对于手术年龄在8岁以下儿童可以明显促进股骨髁的发育,降低股骨滑车角,改善髌股关节适应性;8岁以上儿童在随访期内股骨滑车角的变化不显著,髌股关节适应性改变不明显.     

Factors affecting range of flexion after total knee arthroplasty

Many factors affect postoperative range of flexion after total knee arthroplasty (TKA). The purpose of this study was to identify the most important factors that affect range of knee flexion after TKA. Sixty-five patients (73 knees) were treated with Genesis II knee replacements. Minimum follow-up was 2 years. Patient demographics (sex, age, body mass index, previous surgery, component type, patella resurfacing, preoperative Knee Society score preoperative range of motion) and radiographic measurements (preoperative tibiofemoral varus/valgus angle, height of the joint line, length of the patellar tendon, shift and tilt angle of the patella) were analyzed statistically. Among these factors, preoperative range of flexion, positively, and preoperative varus/valgus tibiofemoral angle, negatively, affected postoperative range of flexion. The tilt angle of the patella and the tilt angle of the patellar button approached statistical significance in revealing a negative relation with postoperative range of flexion. TKAs in which the patella was not resurfaced tended to lose range of flexion, whereas TKAs in which the patella was resurfaced tended to have no loss of flexion, although the number of TKAs in which the patella was not resurfaced was small. In conclusion, preoperative range of flexion and preoperative varus/valgus tibiofemoral angle affected postoperative range of flexion. The tilt angle of the patella and tilt angle of the patellar button may be factors that affect postoperative range of flexion. Received: September 28, 2000 / Accepted: January 9, 2001     

Patellar dislocation following total knee replacement

The reported incidence of patellar problems after total knee replacement has ranged from 5 to 30 per cent. Patellar dislocation is infrequent but can cause disabling symptoms. Between January 1974 and May 1982, eleven patients (twelve knees) with symptomatic lateral dislocation of the patella after total knee replacement were treated at The Hospital for Special Surgery by realignment of the extensor mechanism. All of the patients were women. Their average age was sixty-two years and average weight, eighty-seven kilograms. The diagnosis was osteoarthritis in seven knees and rheumatoid arthritis in five. Most of the patients had had preoperative valgus deformity (average, 18 degrees). The cause of dislocation was trauma in three knees, incorrect tracking of the patella after replacement in six, and malrotation of the tibial component in three. Four different prosthetic designs had been used. The design of the implant did not appear to be a factor causing dislocation in this group. The patellar dislocation was treated by proximal realignment of the quadriceps in ten knees, lateral retinacular release alone in one, and revision of the tibial and femoral components combined with proximal realignment in one. After an average follow-up of thirty-four months (range, twenty-four to fifty-seven months), the results according to The Hospital for Special Surgery knee-rating scale were excellent in ten knees and good in two, and there had been no redislocations.     

Medialization of the patella in total knee arthroplasty

Patellar complications of total knee arthroplasty remain the most common cause of pain and reoperation. Laboratory studies have suggested that medialization of the patella will improve tracking of the patella on the trochlea of the femoral component. The purpose of this study was to determine if clinical medialization of the patellar component on the patellar bone would improve tracking of the patella as demonstrated radiographically. Sixty-two knees were randomized so that 31 knees had a centrally placed patellar component and 31 had the patellar component placed on the medial two thirds of the patellar bone. There was no difference between the two groups with respect to either clinical or radiographic results in the first year after surgery. There was no improvement compared with previous reports in the incidence of tilt and displacement. The one improvement was a reduction in the incidence of lateral release. Thus, consequences of lateral release such as postoperative morbidity, avascular necrosis of the patella, and stress fracture of the patella can be avoided. It is recommended that the patellar component be placed on the medial two thirds of the patella to reduce the occurrence of lateral release. Tracking of the patella during surgery can be assessed using a single suture placed at the superior pole of the patella, and this technique in combination with the no-thumbs test provides an additional means of evaluation for patellar tracking.     

Congenital dislocation of the patella

Purpose Congenital dislocation of the patella is permanent and manually irreducible, and it manifests immediately after birth with flexion contracture of the knee, genu valgus, external tibial torsion and foot deformity. We retrospectively reviewed the results of operative treatment of seven knees in six patients with congenital dislocation of the patella. Methods The age of the six patients at diagnosis ranged from 8 days to 3.6 years, with an average of 1.3 years, and their age at the time of operation ranged from 0.6 to 3.9 years, with an average of 2.1 years. Serial casting and/or a brace was attempted before surgery in five of seven knees, leading to improvement in the flexion contracture of the knee. All knees were treated operatively in combination with lateral release, medial plication, V-Y lengthening of the quadriceps, medial transfer of the lateral patellar tendon and posterior release of the knee. Results Although these deformities were noticed at birth in all seven knees, diagnosis was delayed in three knees due to the low suspicion of the disease and invisible patellae on radiographs. Ultrasonography confirmed the diagnosis of dislocation. The patella was centered in the groove of the femoral condyle after surgery in all knees, but subluxation of the knee with flexion was observed in one knee in which the operation was performed at 3.9 years. Genu valgus and external tibial torsion improved after surgery in all knees. The operated knee was mobile in all cases, with less than 10° flexion contracture of the knee. Flexion contracture did not increase in any of the knees. Conclusion Congenital dislocation of the patella should be suspected in every patient with knee flexion contracture, genu valgus, external tibial torsion, foot deformity and delayed walking. Successful results were obtained when the operation was performed in younger children. Other procedures, such as the semitendinosus tenodesis or tendon transfer, might have to be combined to achieve better stability with flexion in older children. None of the authors received financial support for this study.     

The relationship of lateral release and tourniquet deflation in total knee arthroplasty

A total of 242 knees in 198 patients undergoing total knee arthroplasty were reviewed to evaluate the effect of tourniquet deflation on lateral release rates, possible variables associated with the need for lateral release, and adequacy of intraoperative evaluation on final radiographs. The need for lateral release was determined using the "no-thumbs" and "full contact" rules and visual evaluation. Lateral release was performed after tourniquet deflation. A total of 171 (71%) knees needed a lateral release before tourniquet deflation. After tourniquet deflation, only 53 (22%) required lateral release, representing a 69% reduction. Obesity was the only other significant factor in lateral release requirement. Based on the observations of this study, it is recommended that the need for lateral release be evaluated after tourniquet deflation. A 69% reduction in lateral release supports the hypothesis that tourniquet pressure has an effect on patellar tracking. Lateral release appears to be effective in restoring normal patellar tilt, and obesity increases its need.     

止血带对全膝关节置换术中股骨远端旋转定位时髌骨轨迹的影响

目的 探讨止血带对全膝关节置换术中以外科髁上轴线为股骨远端旋转定位线的髌骨轨迹的影响.方法 2002年12月至2008年8月,首选以外科髁上轴线为股骨远端旋转定位标志的初次全膝关节置换349例(526膝),男124例(155膝),女225例(371膝);年龄33～84岁,平均68岁.膝内翻387膝,膝外翻94膝.均使用同一种保留后十字韧带的活动平台假体,由同一位手术医生操作.采用前内侧髌旁入路,以外科髁上轴线为股骨远端旋转定位线,以no thumb test检测髌骨轨迹.对髌骨轨迹不良者,缝合髌骨内上缘支持带并松开止血带.对再次检查髌骨轨迹不良者行外侧支持带松解术.术后3个月患者能够极度屈曲膝关节时摄X线片检查髌骨轨迹.结果 术中no thumb test阳性138膝,其中半脱位12膝(膝外翻),髌骨倾斜126膝(膝外翻74膝).缝合髌骨内上缘支持带并松开止血带后,no thumb test阳性40膝,其中半脱位8膝(膝外翻),髌骨倾斜32膝(膝外翻29膝).髌骨外侧支持带松解率7.6%(40/526),膝外翻松解率39.4%(37/94).结论 在全膝关节置换术中,高压止血带对髌骨轨迹有干扰作用.术中缝合髌骨内上缘支持带并松开止血带,可降低外侧支持带松解率.     

The Elmslie-Trillat procedure for recurrent patellar subluxation after total knee arthroplasty

Patellofemoral problems are the most common complications after total knee arthroplasty (TKA). We report a patient who had patellar subluxation twice within 7 months after primary TKA. Postoperative radiographs and computed tomography scans revealed a valgus knee with no evidence of malposition of the prostheses. To eliminate the recurrent patellar subluxation, we finally performed an Elmslie-Trillat procedure in combination with extensive lateral release and succeeded in achieving normal patellar tracking. At 1-year postoperative follow-up, the patient was satisfied with the results. The patella tracked well in the femoral trochlear groove during knee flexion after the revision surgery. This procedure, in combination with lateral release, should be considered as a useful surgical treatment that can eliminate patellar subluxation after TKA in cases without component malposition.     

不置换髌骨膝关节置换术后髌骨不稳的原因及预防

目的 探讨全膝关节置换术后髌骨不稳的原因和预防措施.方法 1997年9月至2005年4月对94例(105膝)膝骨关节炎患者行全膝关节置换术.术前膝外翻14例,膝内翻80例,力线正常者11例.所用假体包括可旋转铰链型膝假体RK 10例14膝,活动衬垫型膝假体TACK 40例43膝,GEMINI假体44例48膝,所有患者均不置换髌骨.术前、术后在屈膝30°髌骨轴位片上测量髌骨的排列.结果 术前有膝外翻和髌骨不稳者术后髌骨不稳的发生率分别为28.6%和29.5%,使用RK、TACK、GEMINI假体的患者髌骨不稳的发生率分别为28.6%,20.9%和16.7%.4例有明显股骨或胫骨假体旋转异常.结论 膝关节置换术后出现髌骨不稳定的原因包括患者术前状态、假体设计、假体位置不良等.选择合适的假体,熟练掌握手术技巧,能明显减少膝关节置换术后髌骨轨迹异常.     

Preoperative Radiological Parameters Predicting the Need for Lateral Retinacular Release in Total Knee Arthroplasty

BackgroundProper patellar tracking is essential for well-functioning total knee arthroplasty (TKA). Besides implanting components in the correct position and rotation, balancing parapatellar soft tissues is also important in aiding normal patellar tracking. Patellar maltracking during TKA can be improved by lateral retinacular release (LRR).MethodsWe studied the incidence of LRR in consecutive primary TKA with nonresurfaced patella and posterior-stabilized implant design. We analyzed data from 250 consecutive primary TKAs (212 patients) from January 2016 to May 2016. We evaluated the preoperative radiological parameters like patellar tilt, patellar shift, patellar morphology, Insall-Salvati ratio, femoro-tibial angle, distal femoral valgus angle, and proximal tibia varus angle which predict the need for LRR during TKA. We used multivariate regression analysis to find the association of individual radiological parameters and the LRR.ResultsThe need for LRR is significantly associated with preoperative radiological parameters like patellar shift and patellar tilt (P < .001). Compared to the nonreleased group, the adjusted odds of LRR were greater for morphological parameters like Wiberg type 3 patella (odds ratio [OR] 17.45, 95% confidence interval [CI] 7.21-42.20), lateral facet thinning (OR 4.38, 95% CI 2.37-8.07), lateral patellofemoral arthritis (OR 14.36, 95% CI 6.82-30.23), and coronal valgus deformity (OR 4.95, 95% CI 1.60-10.68).ConclusionPreoperative assessment of these radiological parameters in the axial view implies a high chance of tight lateral retinacular structures. This helps in identifying patients who have a higher likelihood for patellar maltracking during TKA. Appropriate LRR helps to provide better patellar tracking post TKA.     

Lateral patellar release and bone grafting of the tibial plateau in total condylar knee arthroplasties. A technical note

In a review of 50 primary total condylar knee arthroplasties in 25 female and in 14 male patients the factors affecting the necessity of lateral patellar release and bone grafting of the medial tibial plateau were established. Lateral patellar release was performed in 18 of 33 arthroplasties in female patients, in only two of 17 operations in male patients, and on all but one of the knees with preoperative valgus deformity. Bone grafting of the medial tibial plateau was necessary mainly in small knees, i.e., for six of 18 small prostheses in contrast to one of 15 standard-sized implants in female patients and in none of the operated knees in males.     

Three-dimensional transfer of the tibial tuberosity for patellar instability with patella alta

Background

Although patellar instability can be treated with several surgical procedures, the appropriate surgical treatment for patellar instability with patella alta has not yet been investigated. The objective of this study is to find out whether three-dimensional transfer of the tibial tuberosity elicits good knee functionality with improved patella alta and prevents further patellar dislocation.

Methods

Twelve knees (10 patients) underwent surgery for patellar instability with patella alta from 2007 to 2011. The surgery performed was a three-dimensional transfer for the anteromedial distalization of the tibial tuberosity. Predisposing anatomical factors for patellar instability were evaluated preoperatively; femorotibial angle (FTA), patella alta (IS ratio), trochlear dysplasia (sulcus angle) and tilting angle (lateral tilt). The function of the knee was assessed before and after surgery by Lysholm and Kujala score.

Results

Before surgery, the IS ratio was 1.34 ± 0.13, lateral tilt was 22.4° ± 6.5°, and the sulcus angle was 151.7° ± 8.3°, indicating patella alta, laterality, and trochlear dysplasia. After surgery, the IS ratio and lateral tilt significantly improved to 0.95 ± 0.13, and 10.6° ± 3.4°, respectively. FTA and sulcus angle were not altered. Lysholm and Kujala score improved from 63.8 to 94.7 and 67.0 to 94.1 points, respectively. Most patients displayed good outcomes except for one patient who suffered re-dislocation by hitting their knee on the floor, 2.5 years after surgery.

Conclusion

Three-dimensional tibial tuberosity transfer was shown to correct the patella position and result in a good clinical outcome. This method is introduced as an alternative surgery for patellar instability with patella alta.     

Correction of knee deformity in patients with Ellis-van Creveld syndrome.

Six knees in three patients with Ellis-van Creveld syndrome were treated with lateral soft tissue release and corrective osteotomy of the tibia at 10 years of age on average. The main feature was valgus deformity with lateral dislocation of the patella. All patellae were reduced. The valgus deformity improved from 35 degrees (range, 48 degrees-20 degrees) to 17 degrees (range, 35 degrees-5 degrees) of the femorotibial angle (FTA) on average, although the FTA in five of six knees was < 5 degrees after surgery. There was one recurrent case and one transient peroneal nerve palsy. The reason for undercorrection was a depression of the lateral tibial plateau. The deformity of the articular surface is the most important problem in correcting the valgus deformity of the knee in this syndrome.     

Preoperative computed tomography scanning and arthroscopy in predicting outcome after lateral retinacular release.

We initiated a study to look at preoperative, flexed-knee, midpatellar computed tomography (CT) scans and intraoperative arthroscopic findings of lateral patellar articular degeneration in predicting the results after lateral retinacular release for failed nonoperative treatment of anterior knee pain. Twenty patients with 30 painful knees underwent preoperative flexed-knee, midpatellar CT scans that were retrospectively classified by the method of Fulkerson into normal alignment, lateral subluxation, lateral patellar tilt, and combined tilt and subluxation. Arthroscopy was performed before open lateral release. The lateral facet of the patella was graded as either minimal changes (Outerbridge I or II) or advanced (Outerbridge III or IV) changes. Patients were followed for a minimum of 2 years and graded on a standard patellofemoral rating scale. Only 22 of 30 knees that were thought to be clinically malaligned, actually were malaligned by CT scan; eight CT scans were interpreted as normal. The results were further stratified into group A (CT-documented tilt, minimal facet changes), group B (CT-documented tilt, advanced facet changes), and group C (normal CT). Ninety-two percent of group A were rated good or excellent. Twenty-two percent of Group B rated good/excellent, 33% fair, 44% poor. Only 13% of group C rated good (one patient). Based on the results of the study, we recommend lateral release for anterior knee patients with CT-proven patellar tilt who have not responded to conservative treatment and have minimal facet changes with minimal or no subluxation. Lateral retinacular release should not be offered as a treatment to the patient with a normally aligned patella because poor results will most likely result.     

A modified system of stress radiography for patellofemoral instability

Axial radiographs were obtained under valgus and external rotation stress at 45 degrees of knee flexion with and without contraction of the quadriceps muscle in order to assess the dynamics of patellar subluxation or dislocation. The radiography was performed on 82 knees in 61 patients with patellofemoral instability, and on 44 normal knees. The lateral patellofemoral angle and the congruence angle were measured and compared with the conventional Merchant views. Both parameters showed greater differences between symptomatic and normal knees on the stress radiographs obtained without quadriceps contraction. There was a major difference in the lateral patellofemoral angles between the groups, which clearly distinguished symptomatic knees from normal controls. Congruence angles on stress radiography had a significant correlation with the functional scores obtained after a period of conservative treatment and a positive correlation with the frequency of patellar subluxation. When the quadriceps contracted, two patterns of patellar shift were observed. While the patella reduced into the trochlear groove in all normal knees and about 70% of the symptomatic knees, contraction of the quadriceps caused further subluxation of the patella in the remaining symptomatic knees. All the knee joints which showed this displacement failed to respond to conservative treatment and eventually required surgical treatment. Thus, this technique of stress radiography is a simple, cost-effective and useful method of evaluating patellar instability and predicting the prognosis.     

Q-angle influences tibiofemoral and patellofemoral kinematics.

Numerous surgical procedures have been developed to correct patellar tracking and improve patellofemoral symptoms by altering the Q-angle (the angle between the quadriceps load vector and the patellar tendon load vector). The influence of the Q-angle on knee kinematics has yet to be specifically quantified, however. In vitro knee simulation was performed to relate the Q-angle to tibiofemoral and patellofemoral kinematics. Six cadaver knees were tested by applying simulated hamstrings, quadriceps and hip loads to induce knee flexion. The knees were tested with a normal alignment, after increasing the Q-angle and after decreasing the Q-angle. Increasing the Q-angle significantly shifted the patella laterally from 20 degrees to 60 degrees of knee flexion, tilted the patella medially from 20 degrees to 80 degrees of flexion, and rotated the patella medially from 20 degrees to 50 degrees of flexion. Decreasing the Q-angle significantly tilted the patella laterally at 20 degrees and from 50 degrees to 80 degrees of flexion, rotated the tibia externally from 30 degrees to 60 degrees of flexion, and increased the tibiofemoral varus orientation from 40 degrees to 90 degrees of flexion. The results show that an increase in the Q-angle could lead to lateral patellar dislocation or increased lateral patellofemoral contact pressures. A Q-angle decrease may not shift the patella medially, but could increase the medial tibiofemoral contact pressure by increasing the varus orientation.     

全膝关节置换术中放开止血带并缝合内上缘支持带对髌骨轨迹的影响

目的 探讨在初次全膝关节置换术(TKA)中放开止血带且缝合内上缘支持带对髌骨轨迹的影响.方法 选择2006年3月至2008年2月初次行TKA的83例患者136侧膝关节.使用前内侧髌旁人路,检测髌骨轨迹.对于不良的髌骨轨迹,术中松开止血带且仅用一针缝合髌骨内上缘支持带.再次检查髌骨轨迹.最后,对残留不良髌骨轨迹的患者行外侧支持带松解术,以求获得满意的髌骨轨迹.采用no-thumb试验作为检测髌骨轨迹的标准.结果 在初次行TKA的83例患者136侧膝关节中,在未松开止血带前,髌骨轨迹不良率为64.7%(88/136).放开止血带且缝合髌骨内上缘支持带后,髌骨外侧支持带松解率为26.5%(36/136),差异有统计学意义(X2=38.55,P＜0.01).其中,膝外翻畸形患者的松解率为58.6%(17/29),膝内翻和无明显畸形患者的松解率为17.8%(19/107).结论 高压止血带对行前内侧髌旁人路TKA的患者髌骨轨迹的干扰作用非常明显.术中松开止血带且缝合髌骨内上缘支持带明显降低了外侧支持带的松解率,从而降低了其可能带来的并发症.