Patellar dislocation due to iatrogenic quadriceps fibrosis: results of operative treatment in 54 cases

Objective

To evaluate the clinical and functional results of a surgical treatment of patellar dislocation whose etiology was iatrogenic quadriceps fibrosis in children.

Materials and methods

A prospective study was undertaken from February 2004 to December 2009. The study included 54 pediatric patients (56 knees) that had developed dislocation of the patella after repeated intramuscular injections of antibiotic(s) into the quadriceps muscle. There were 11 males (20.4 %) and 43 females (79.6 %). The patients’ mean age at surgery was 7 years, 9 months (range 6 years, 4 months to 12 years, 6 months). A complete history of each patient was recorded. The affected knees were evaluated preoperatively and postoperatively on the basis of the symptoms, signs, and roentgenographic findings. Patellar dislocation was classified according Bensahel’s criteria. All patients had a three-part surgical procedure that combined capsulorrhaphy, quadricepsplasty, and transfer of the vastus medialis oblique to the superior border of the patella.

Results

There has been no poor postsurgical result or recurrence so far; we have noted an ugly scar in nine knees (16.1 %), limitation of the knee flexion in five knees (8.9 %), and loss of extension of 5 °–20 ° in four knees (7.1 %). Overall, we attained excellent results in 39 knees (69.7 %), good results in 13 knees (23.2 %), and fair results in four knees (7.1 %).

Conclusion

In our cases of pediatric dislocation of the patella caused by iatrogenic quadriceps fibrosis, the introduced three-part surgical procedure has shown great success in restoring the realignment mechanism of the patella. The technique is simple, safe, and effective in skeletally immature children.     

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。     

骨性和软组织性髌骨脱位模型中滑车发育的实验研究

目的通过股骨截骨术增大股骨前倾角和髌骨内外侧软组织失平衡手术制作髌骨脱位模型,观察股骨滑车局部形态和骨小梁结构的变化。方法取40只3个月龄的新西兰幼兔,分别对其右膝进行两种手术方式(每组20只):①截骨组,接受股骨旋转截骨术,股骨远端内旋来增大股骨前倾角;②软组织组,行髌骨内侧支持带松解和外侧支持带紧缩缝合术。所有左膝作为正常对照组。术后观察4个月至骨骼成熟,将股骨远端进行Micro-CT扫描,测量滑车形态:外侧髁、滑车沟和内侧髁的高度,滑车沟角,滑车的外侧和内侧关节面倾斜角等,并对骨小梁进行分析:骨体积分数、骨小梁厚度、骨小梁数量、骨小梁分离度和骨密度等。相关指标的结果进行组间比较。结果截骨组中1例发生髋关节脱位,而髌骨未发生脱位;3例在屈膝状态下出现完全性的髌骨脱位;16膝在膝关节被动伸直时,髌骨发生脱位。软组织组中15膝在屈膝状态下出现完全性的髌骨脱位,5膝未发生髌骨脱位。截骨组的股骨滑车在滑车入口处伴有局部的突起形成,称为"骨突",而滑车关节面比较光滑,未出现明显的软骨破裂等,而软组织组的股骨滑车未见"骨突"形成,滑车关节面出现软骨破裂、缺损等关节炎表现。与对照组相比,截骨组和软组织组的滑车均变浅和变宽,滑车沟高度和滑车沟角变大,但两组比较没有统计学差异。与对照组相比,截骨组骨小梁发生汇聚,内侧髁和外侧髁的骨小梁厚度增大,内侧髁骨小梁数量减少,而软组织组表现为骨质疏松,内侧髁和外侧髁的骨体积分数、骨小梁厚度、骨小梁数量和骨密度都减少,骨小梁分离度增大。与软组织组相比,截骨组内侧髁和外侧髁的骨体积分数、骨小梁厚度、骨小梁数量和骨密度都较大,骨小梁分离度较小,差异有统计学意义。结论通过股骨截骨术增大股骨前倾角和髌骨内外侧软组织失平衡手术可成功构建髌骨脱位的骨性和软组织型模型,并继发形成不同的滑车形态学改变和骨小梁结构变化。     

Reconstruction of the Medial Patellofemoral Ligament With Autologous Quadriceps Tendon

In knees with insufficient or previously disrupted medial retinacular and patellofemoral ligaments caused by subluxation or dislocation, anatomic reconstruction of the medial patellofemoral ligament may be performed. This procedure involves harvesting of an 8 × 70-mm medial quadriceps tendon graft, which leaves the quadriceps tendon retinacular attachment intact and avoids patellar and femoral drill holes. This graft is passed beneath the retinaculum adjacent to the femoral epicondyle and is sutured to the medial intermuscular septum—a procedure that reproduces the medial patellofemoral ligament and is supported by imbrication of the remaining medial retinaculum. The tension of the graft and of the medial retinaculum is set at closure with the knee in 30° to 45° of flexion; this allows the patella to be moved a distance equal to 25% of its width. Avoidance of drill holes allows the procedure to be used regardless of skeletal maturity and reduces fracture complications, inadequate graft placement, and failure of fixation. Postoperative rehabilitation includes immediate knee motion from 0° to 90° and partial weight bearing.     

关节镜辅助治疗急性髌骨脱位

目的 探讨关节镜辅助下外侧支持带松解、内侧支持带紧缩治疗急性髌骨脱何的疗效.方法 2006年4月-2009年3月,应用关节镜辅助下改良髌外侧支持带松解、内侧支持带紧缩治疗急性髌骨脱位22例25膝.男5例,女17例;年龄14～34岁,平均23.6岁.均突发于屈膝活动过程中.左侧11膝,右侧14膝.出现症状至入院时间为1～...     

关节镜下髌骨内侧支持带紧缩术治疗青少年复发性髌骨脱位

目的探讨关节镜下髌骨内侧支持带紧缩术(medial retinaculum plication,MRP)治疗青少年复发性髌骨脱位的临床疗效。方法对2000年3月-2007年10月收治的30例符合选择标准的青少年复发性髌骨患者进行前瞻性研究,其中28例获完整随访者纳入研究。男5例,女23例;年龄12～19岁,平均14.7岁。左膝12例,右膝16例。髌骨首次脱位至入院时间4～39个月,平均18.8个月。患者既往髌骨2～4次脱位。患者髌骨外推恐惧试验均为阳性,髌骨外移度为(2.9±0.7)°,髌骨外推无硬性终止点。国际膝关节文献委员会(IKDC)、Lysholm、Kujala以及Tegner评分分别为(47.7±3.7)、(52.6±4.9)、(66.7±5.9)和(3.1±1.3)分。患者均于关节镜下行MRP治疗。结果患者术后切口均Ⅰ期愈合,无感染或神经、血管损伤等早期并发症发生。患者均获随访,随访时间2～7年,平均4.8年。术后随时间延长,髌骨外推恐惧试验阳性患者数逐渐增加,24个月时为12例;髌骨外推有硬性终止点患者逐渐减少,24个月时为3例;髌骨外移度逐渐增加,24个月为(2.3±1.1)°;以上3项指标除髌骨外移度外,与术前比较差异均有统计学意义(P<0.05)。术后6例发生再脱位,23例出现单纯髌骨不稳。术后24个月IKDC、Lysholm、Kujala以及Tegner评分分别为(62.5±6.2)、(70.7±5.1)、(76.6±4.8)和(3.9±0.7)分,均较术前显著提高(P>0.05)。CT检查示,术后即刻患者髌股关节适配角、髌骨外侧角以及髌骨倾斜角均恢复至正常水平,但术后24个月与术前比较差异均无统计学意义(P>0.05);术后24个月髌骨外移距离与术前比较,差异有统计学意义(P<0.05)。结论关节镜下MRP治疗青少年复发性髌骨脱位虽在改善膝关节功能方面有一定疗效,但不能较好维持髌骨矫正后的位置。     

髌股关节发育不良对髌骨脱位磁共振成像表现的影响

背景：当存在髌股关节发育不良时,髌骨脱位的损伤程度较轻,因此更加依赖影像学诊断。 目的：比较髌股关节发育不良患者和髌股关节发育正常患者髌骨脱位时磁共振成像（MRI）表现的异同。 方法：回顾性分析54例经临床证实的髌骨脱位患者的MRI影像学资料。髌股关节发育不良患者32例,髌股关节发育正常患者22例。记录患者MRI中髌骨内侧骨挫伤或撕脱骨折、髌骨关节面骨软骨骨折、股骨外侧髁外侧部骨挫伤、髌股内侧支持带撕裂等情况。 结果：髌股关节发育不良组的32例患者中,髌骨内缘骨折12例,内侧支持带损伤10例,髌骨软骨损伤7例,股骨外髁骨挫伤18例;髌股关节发育正常组的22例患者中,髌骨内缘骨折8例,内侧支持带损伤14例,髌骨软骨损伤14例,股骨外髁骨挫伤14例。两组在内侧支持带损伤和髌骨内缘骨折上有显著统计学差异（P＜0.05）。 结论：MRI可以较好地诊断髌骨脱位。当髌股关节发育不良时,内侧支持带损伤和髌骨内缘骨折的发生率降低。     

急性髌内侧支持带损伤关节镜下修复术的疗效

目的:采用高频超声对急性髌内侧支持带损伤进行准确定位,利用定位点行髌内侧支持带修补术探讨其疗效。方法:回顾性分析2009年6月至2014年3月收治的急性髌骨脱位患者17例,男6例,女11例;年龄11~40岁,平均(16.2±6.2)岁;病史2周以内。术前均行髌内侧支持带的高频超声检查,并对韧带纤维不连续的点位做皮肤标示。5例髌内侧支持带自体部损伤者行关节镜下过线缝补;12例支持带自髌骨边缘止点撕脱者将锚钉固定在骨内,用锚钉自带线缝补。术前及随访18个月时,进行Kujala评分和CT测量髌骨倾斜角,查最大主动、被动屈膝度及髌骨恐惧症。结果:随访18个月后Kujala评分92.2±11.1,髌骨倾斜角(11.5±4.2)°,与受伤前差异无统计学意义。最大主动屈膝(133.5±4.2)°,与正常值无差异。最大被动屈膝(153.5±4.6)°,超声显示髌内侧支持带纤维连续。髌骨恐惧症1例,无髌骨不稳复发。结论:髌内侧支持带损伤在超声定位下完成了准确的定位和关节镜下的修补,术后制动时间短。随访18个月,膝关节功能满意,无髌骨不稳复发。     

Quadriceps dislocation medial approach for intraarticular and medial structures of the knee

To minimize possible complications such as patellar subluxation, quadriceps atrophy and skin tightness and slough which interfere with successful rehabilitation following knee surgery, the author employed a quadriceps dislocation medial approach for total knee arthroplasty and ligament (medial and both cruciates) surgery. The results of this approach (99 knees) were compared with a medial capsular incision approach (111 knees), a lateral capsular incision approach (114 knees), and Hughston's medial hockey stick incision approach (122 knees). The skin slough, patellar subluxation, and sense of tightness during rehabilitation occurred least with the quadriceps dislocation medial approach (P less than .05). The quadriceps dislocation medial approach was also the most convenient approach of the four.     

Surgical treatment of habitual dislocation of the patella in childhood

Surgical Principles Medial displacement of the medial half or the medial two thirds of the patellar ligament on the proximal tibia; the detached ligament is anchored to a chiselled trough in the bone with a cancellous bone screw and serrated washer. Division of the fibres of the tractus iliotibialis leading into the patella and of the lateral extensor retinaculum up to the vastus medialis (so-called “lateral release”). Transfer of the vastus medialis in lateral and distal direction by approximately 1 to 1.5 cm onto the patella. Double breasting of the medial extensor retinaculum. First published in: Operat. Orthop. Traumatol. 1 (1989), 94–99 (German Edition).     

关节镜辅助下小切口重建内侧髌股韧带治疗创伤性复发性髌骨脱位

目的探讨关节镜辅助下小切口同种异体肌腱重建内侧髌股韧带(MPFL)治疗创伤性复发性髌骨脱位的临床效果。方法回顾性分析自2006年1月～2010年4月共收治28例创伤性复发性髌骨脱位,所有患者在第一次脱位均为膝关节外伤所致,伤后患膝明显肿胀及髌骨脱位-复位感,此后出现髌骨脱位3次以上者。手术方法:先行关节镜检查,髌骨外侧支持带紧张者行松解术,关节镜监视下调整MFPL的张力并于其解剖止点以同种异体肌腱重建MFPL,术后接受正规功能康复锻炼。结果术后平均随访26个月(12～36个月)。重建术后无髌骨再次脱位发生,髌股关节稳定。术前、术后均采用Lysholm和Kujala膝关节评分标准,手术前后评分差异有统计学意义(P<0.05)。结论选择适当的病例,重建内侧髌股韧带是治疗创伤性复发性髌骨脱位的有效方法。     

关节镜下改进紧缩髌骨内侧支持带治疗复发性髌骨脱位

目的 探讨关节镜下改进紧缩髌骨内侧支持带治疗复发性髌骨脱位的疗效.方法 我科于2013年7月至2015年7月收治复发性髌骨脱位病人23例,男4例,女19例,年龄为10~25岁,平均为15.8岁.手术在关节镜下操作,用等离子刀常规进行松解髌骨外侧支持带,用ACCU PASS自动连续传递缝合钩将PDS缝线四等分整体跨越髌骨内侧支持带,采用对称集中打结法拉紧缝线,实现对髌骨内侧支持带的有效紧缩.术后鼓励病人在膝关节支具保护下早期进行功能锻炼.比较手术前后Lysholm膝关节评分、Tegner膝关节运动水平评分和髌骨外移度.结果 单膝的关节镜下操作时间为40~55 min,平均为46.4 min.术中实现髌股关节面复位,屈膝关节活动(0°~90°)时髌骨活动轨迹满意,病人没有发生再脱位.随访时间为18~36个月,平均为24.6个月.末次随访时病人髌骨位置满意,膝关节静息位或屈伸活动时未发生髌骨再脱位.术后18个月Lysholm膝关节评分为(79.6±5.4)分、Tegner膝关节运动水平评分为(5.4±0.9)分、髌骨外移度为(3.8±1.1)mm与术前的(51.9±7.9)分、(2.8±1.2)分、(11.8±2.1)mm比较,差异均有统计学意义(均P<0.05).结论 关节镜下采用ACCU PASS自动连续传递缝合钩可以方便对髌骨内侧支持带紧缩的操作,PDS缝线行对称集中式打结能获得坚强的固定紧缩效果,本方法具有操作便捷、固定强度好、膝关节功能恢复快、近期疗效好的特点.     

关节镜下内侧髌股支持带缝合与石膏固定治疗急性髌骨脱位的病例对照研究

目的:比较关节镜下髌内侧支持带紧缩术和石膏固定法治疗急性髌骨脱位的疗效.方法:回顾性分析2006年2月至2012年10月收治的急性髌骨脱位患者29例,病史2周以内,年龄9～31岁,分为手术组和非手术组.手术组17例,男7例,女10例,平均年龄(16.2±6.2)岁,采用关节镜下髌内侧支持带紧缩术治疗;非手术组12例,男5例,女7例,平均年龄(16.3±5.0)岁,行石膏外固定治疗.治疗前及随访1年时,进行Kujala评分,行CT检查测量髌骨倾斜角,观察髌骨恐惧症发生情况.结果:手术组治疗前后髌骨倾斜角差异无统计学意义,治疗后Kujala评分低于治疗前;非手术组治疗后髌骨倾斜角大于治疗前,Kujala评分低于治疗前.随访1年,手术组Kujala评分84.1±5.6,高于非手术组73.3±10.5;髌骨倾斜角(13.5±3.5)°,小于非手术组(21.2±5.3)°.结论:关节镜下采用髌内侧支持带紧缩术治疗急性髌骨脱位相比石膏外固定治疗,在术后1年之内具有更好的效果.     

Outcomes of medial patellofemoral ligament reconstruction and tibial tubercle osteotomy in syndromic adolescents with patellar dislocation

BackgroundTreatment of congenital and habitual dislocation of the patella in syndromic adolescents can be difficult due to accompanying soft-tissue and/or osseous abnormalities often present in the knee. The aim of this study was to report the results of surgical treatment of congenital and habitual patellar dislocation with medial patellofemoral ligament (MPFL) reconstruction and tibial tubercle osteotomy (TTO) in adolescents with an underlying syndrome.MethodsSyndromic adolescent patients with congenital or habitual patellar dislocation treated with MPFL reconstruction and TTO between 2005 and 2019 with a minimum of one year of follow-up were identified. Demographic, clinical, radiographic, and surgical data were recorded, and any complications were noted. Kujala and Lysholm scores were used to quantitate knee function.ResultsSeventeen knees in 11 patients met the criteria for inclusion. The mean age at operation was 14.8 years (range, 13.3–18.3 years). Patients were identified as having Ehlers-Danlos (four), Down (two), trichorhinophalangeal (one), McCune-Albright (one), Klippel-Feil (one), and generalized joint hypermobility (two) syndromes. The mean follow-up was 2.2 years for each individual knee (range, 1–5.9 years). The mean Kujala score increased from 56 ± 10 preoperatively to 86 ± 6 at the most recent postoperative visit (p < 0.001). The mean Lysholm score increased from 53 ± 10 preoperatively to 85 ± 7 at the most recent postoperative visit (p < 0.001). Knee flexion increased significantly from 117° ± 15° preoperatively to 154° ± 13° postoperatively (p < 0.001). However, knee extension was no different pre- and postoperatively (4° ± 8° vs. 1° ± 4°, respectively, p = 0.2).ConclusionsCongenital and habitual patellar dislocation in adolescent-aged patients with an underlying syndromic diagnosis can be successfully treated with MPFL reconstruction combined with TTO.     

Lateral Dislocation of the Patella Following Marmor and Guepar Arthroplasty of the Knee

The follow-up of 50 knees treated with the modular Marmor prosthesis and 50 with the Guepar hinge joint included tangential radiography of the femoro-patellar joint. After Marmor arthroplasty lateral patellar dislocation was found in seven knees, in six causing pain. After Guepar arthroplasty lateral patellar dislocation was found in 32 knees, but pain was present in only three. There was only a questionable correlation between pre-existing valgus deformity and postoperative lateral patellar dislocation, and an external rotation deformity of the lower leg was found in only five cases after Guepar arthroplasty. Thus, neither phenomenon could explain the high incidence of lateral patellar dislocation in the Guepar series. These dislocations must be assumed to be due to the unphysiological strain on the extensor apparatus inherent in this type of prosthesis.     

内侧髌股韧带重建联合胫骨结节移位和关节镜下外侧支持带松解术治疗持久性髌骨脱位

目的观察内侧髌股韧带重建联合胫骨结节移位和关节镜下外侧支持带松解术治疗持久性髌骨脱位的效果。方法对6例持久性髌骨脱位患者的10个膝关节行内侧髌股韧带重建联合胫骨结节移位和关节镜下髌骨外侧支持带松解术。手术前后采用Lysholm膝关节功能评价表和Kujala评分表进行评估,并通过CT观测手术前后髌骨外移度。结果 6例均获随访,时间24～36(29±7.21)个月。Lysholm评分术前为47.10分±10.31分,术后24个月为83.11分±5.21分,差异有统计学意义(P<0.05);Kujala评分术前为41.26分±13.36分,术后24个月为82.33分±5.31分,差异有统计学意义(P<0.05)。患膝运动能力均较术前明显改善。髌骨外移度术前为35.61 mm±5.37 mm,术后为4.30mm±1.13mm,差异有统计学意义(P<0.05)。结论内侧髌股韧带重建联合胫骨结节移位和关节镜下髌骨外侧支持带松解术能够有效纠正持久性髌骨外侧脱位,缓解症状,恢复膝关节功能。     

复发性髌骨脱位的治疗进展

复发性髌骨脱位主要表现为髌骨反复性脱位、"打软腿"等,大多有外伤史或膝关节发育不良的基础。传统治疗方法包括内侧支持带紧缩、外侧支持带松解、胫骨结节移位、股骨滑车成型术等。近年来随着对内侧髌股韧带(MPFL)解剖结构及生物力学的研究逐渐深入,MPFL防止髌骨脱位的作用越来越被重视,通过重建MPFL来恢复髌骨正常轨迹日益增多。目前尚无一种术式能够完全治疗复发性髌骨脱位,具体治疗根据患者的解剖及生物力学情况,选择合适的术式联合治疗,恢复患者的髌骨稳定性、下肢力线及尽可能恢复膝关节功能。     

Acquired permanent dislocation of the patella in a patient with rheumatoid genu valgum

A case of acquired permanent dislocation of the patella associated with severe genu valgum in a patient with rheumatoid arthritis (RA) is herein reported. The pain and genu valgum progressed because of poor RA control. The patient had no history of major trauma of the knee before or after the onset of RA. The most reasonable hypothesis to explain this patient''s pathology is that occult patellar dislocation developed after a minor trauma and progressed to permanent dislocation; poor RA control then worsened both the patellar dislocation and genu valgum. Total knee arthroplasty (TKA) with patella reduction was successfully performed with release of the lateral retinaculum and extension of the extensor mechanism by partial snipping of the rectus femoris tendon. Two years after the operation, the patient exhibited improvement in her Knee Society Knee and Function Scores from preoperative scores of 18 and 20 to postoperative scores of 94 and 80, respectively. Acquired permanent dislocation of the patella associated with severe genu valgum in patients with RA is rare. Excellent results were obtained with TKA, and the proximal realignment method was a useful procedure for patella reduction.     

Role of peripatellar retinaculum in transmission of forces within the extensor mechanism

BACKGROUND: The role of the peripatellar retinaculum as a frontal plane stabilizer of the patellofemoral joint has been well established. However, as a result of its unique orientation, the retinaculum also may influence the distribution of forces within the extensor mechanism. The objective of this study was to determine the extent to which the peripatellar retinaculum affects the magnitude of forces experienced by the patellar tendon. METHODS: Ten cadaver knees were used in this investigation. Each was mounted on a custom test apparatus that was fixed to an Instron frame. The extensor mechanism was loaded by applying forces through the individual heads of the quadriceps femoris. Patellar tendon tension was measured at 0 degrees , 20 degrees , 40 degrees , and 60 degrees of knee flexion with use of a buckle transducer under two conditions: (1) with the peripatellar retinaculum intact, and (2) with the peripatellar retinaculum removed. Patellar tendon tension was compared between the two conditions across the knee flexion angles. RESULTS: At each knee flexion angle, the patellar tendon tension was greater with the retinaculum removed than it was with the retinaculum intact. However, the difference was significant only at 0 degrees and 60 degrees , at which positions the force transmitted to the patellar tendon was increased by 16.6% and 9.6%, respectively. Conclusions: The observed increases in patellar tendon tension after removal of the peripatellar retinaculum is an indication of the load-sharing function of that structure as a part of the extensor mechanism. CLINICAL RELEVANCE: Our results suggest that compromise of the peripatellar retinaculum may alter patellar tendon and/or patellofemoral joint forces.     

Congenital dislocation of the patella. Part II: orthopaedic management

Five patients (eight knees) with diagnosed congenital dislocation of the patella and well-documented charts were reviewed. Age at diagnosis ranged from 4 days to 6 years. A flexion contracture of the knee and femorotibial rotatory dislocation of varying degrees were present in all the cases. The quadriceps was active in all the cases, producing knee flexion in four cases. Foot deformity was associated in all the cases (clubfoot, calcaneovalgus, or congenital vertical talus). Gradual correction of knee flexion contracture with serial casting was attempted in five cases leading to an almost complete extension in two cases. Treatment of patellar dislocation was surgical in all the cases, consisting in extensive quadriceps release (seven knees) or V-Y lengthening (one knee), division of lateral soft tissues, and reefing of the medial retinaculum and capsule. Intraoperative anomalies were recorded. At an average follow-up of 6.9 years, all the patients are able to walk on their operated limb, and the patella is centered in the trochlea in all the cases. Knee mobility, rotatory dislocation, and daily function were improved in seven cases.