Acute lateral dislocation of the patella: correlation of ultrasound scanning with operative findings

Acute lateral dislocation of the patella has been associated with disruption of the medial restraints of the patella. Following non-operative management there is a re-dislocation rate of up to 44%. The purpose of this study was to test whether sonography is a reliable method of assessing the medial retinaculum after acute dislocation of the patella. Ten patients following acute patellar dislocation had an ultrasound scan (USS) performed by an experienced musculoskeletal radiologist. Each patient subsequently had an examination under anaesthetic, arthroscopy, and repair of the ruptured structures. The ultrasound reports were compared to the surgical findings to determine the accuracy of this investigation. USS located deficiencies in the ligamentous attachments to the medial border of the patella and the presence of avulsed bony fragments, all of which were confirmed at operation. The sonographic diagnosis of haematoma or torn fibres in the vastus medialis obliquus (VMO) corresponded with our operative findings. The most significant findings were the correlation of free fluid around the medial collateral ligament (MCL) with avulsion of the femoral attachment of the medial patellofemoral ligament (MPFL) and the presence of avulsed fragments of bone from the medial border of the patella.     

Arthroscopic patella realignment: An all-inside technique

Purpose: Many methods of realigning the patella have been described. Most techniques for proximal realignment involve an open medial reefing or advancement of the vastus medialis obliquus. Arthroscopically assisted methods have been described, but these all involve the need for a medial incision to tie sutures. This article describes an entirely arthroscopic technique for proximal realignment that eliminates the need for an incision, and reports the 2-year follow-up results using this technique. Type of Study: Retrospective review. Methods: Over a 5-year period, 26 patients (29 knees) with patellar instability were treated with an outpatient arthroscopic all-inside medial reefing and lateral release. Arthroscopic reefing was performed by percutaneous passage of suture followed by arthroscopic retrieval and knot tying inside the joint. Before knot tying, a healing response was initiated along the medial retinaculum by either gentle shaving with a whisker blade or by radiofrequency thermal response. Rehabilitation consisted of 1 week of immobilization followed by an accelerated program of range of motion exercises and vastus medialis obliquus strengthening. Results: At follow-up, 93% of patients reported significant subjective improvement. The average Lysholm score improved from 41.5 to 79.3 (P < .05). Preoperative and postoperative radiographs were measured for congruence angle, lateral patellofemoral angle, and lateral patella displacement, and all showed significant improvement postoperatively (P < .05). There were no complications and no redislocations. Patients reported a significant improvement in pain, swelling, stair climbing, crepitus, and ability to return to sports (P < .05). Conclusions: Arthroscopic patella realignment is a viable technique that offers results comparable or superior to published results for open or arthroscopically assisted realignment.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 9 (November-December), 2001: pp 940–945     

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。     

Delayed Reduction of Irreducible Chronic Posterolateral Dislocation of the Knee with Buttonholing of the Medial Femoral Condyle

Abstract Traumatic knee dislocations are relatively rare and almost always respond to closed reduction; however, a small percentage of knee dislocations are irreducible and in these cases open reduction is frequently required. A 65-year-old man with an unreduced posterolateral knee dislocation with laterally dislocated patella was seen 3 weeks after a motor vehicle accident. Medial femoral condyle was found buttonholed through the medial capsule together with the medial collateral ligament and lying in the medial joint space that allowed posterior rotary dislocation of the joint. Both cruciate ligaments and medial meniscus were torn. There was no evidence of any vascular or nerve injury. Reduction was accomplished by removal of the capsuloligamentous structures which were incarcerated in the trochlea and intercondylar notch and by excision of meniscal tear. Following posterior cruciate ligament reconstruction with patellar tendon autograft, lateral patellar release, vastus medialis advancement, and gracilis transfer were done.     

Insall Proximal Realignment of the Patella for Recurrent Dislocation or Subluxation

Objective

Proximal realignment of the patella for the treatment of patellar subluxation or dislocation consisting of a lateral release and advancement of the vastus medialis.

Indications

Recurrent lateral subluxation or dislocation of the patella despite a supervised exercise program. Recurrent subluxation or dislocation of the patella.

Contraindications

Congenital dislocation of the patella. Generalized degenerative arthritis of the patellofemoral joint. Excessive valgus deformity of the knee. Moderate to severe muscular atrophy of the vastus medialis muscle (i.e., in neurologic disorders).

Surgical Technique

Lateral parapatellar incision of skin. Detachment of the fibers of the iliotibial tract and the lateral retinaculum from the lateral patella. Medial capsular incision extending from the quadriceps tendon over the patella into the patellar ligament. The quadriceps expansion is shaved from the medial third of the patella preserving the longitudinal continuity. The vastus medialis is advanced and sutured onto the middle and distal aspects of the patella.

Results

Out of 21 patients (16 women, five men) who received a proximal realignment procedure during 1989 and 1993, all could be evaluated after 6.3 years (minimum follow-up of 4 years 5 months, maximum of 8 years 3 months). In 13 patients the diagnosis was recurrent dislocationof the patella, in eight patients a true primary traumatic dislocation was noted. A generalized ligamentous laxity was seen in three patients. One patient had a superficial wound infection postoperatively. Two patients had an excellent, 13 patients a good, six patients a fair and no patient a poor result according to the subjective score of Turba et al. Three patients experienced a recurrence of instability (one to three events) after the operation. One of these patients had to be revised for postoperative recurrent dislocation of the patella. The other two patients experienced no more symptoms of instability after muscle strengthening exercises of the vastus medialis muscle.     

髌骨半脱位70例治疗分析

目的探讨髌骨半脱位的治疗方法及其预后。方法回顾性分析70例（130膝）髌骨半脱位患者的临床资料,其中男30例,女40例;年龄10～48岁,平均23岁。患者髌骨的形态均为WibergⅡ、Ⅲ型,其中伴有外侧髌股关节骨关节炎者58例108膝,高位髌骨23例46膝,外伤后股四头肌内侧头肌张力不良10例10膝。Q角20°～40°。全部行手术治疗,手术方式包括：髌外侧支持带充分松解（130膝）;髌内侧支持带紧缩、股内侧肌移位至髌骨前内侧（12膝）;髌骨外侧部分切除（17膝）;胫骨结节前、内侧移位（46膝）,平均内移1．0cm、前移1．2cm;缝匠肌前移（11膝）,半腱肌前移（13膝）;关节镜下髌外侧支持带松解,髌内侧支持带紧缩（31膝）。术中见全部病例髌外侧支持带均明显增厚。结果随访3～180个月,根据Insall等评分系统评估分析疗效,术后疗效优78膝,良33膝,可12膝,差7膝。患者术后疼痛、关节活动功能均得到明显改善,尤其是解除膝前痛效果显著。结论根据病因及病理改变选择恰当的手术方式治疗髌骨半脱位均可取得满意的效果,特别是关节镜手术具有创伤小、恢复快的特点,值得进一步推广应用。     

Patellofemoral disorders and instability

Originally the main idea was to obtain a stable patella, i.e., to stabilize the "slipping patella". In the past many conditions like patella alta, ligamentous laxity, PF bone hypoplasia, weakness of the quadriceps muscle, genu valgum or genu recurvatum were thought to predispose to patellar instability. For a long period muscle exercises were instituted to strengthen the weak m.vastus medialis and to make vastus lateralis stronger. This pulls the patella laterally, especially during running or jumping, when lateral luxation of the patella occurs. Muscle imbalance as well as anatomical abnormalities are the basis both for patellar instabilities and reasonable surgical procedures were: proximal extensor mechanism realignment, proximal capsular reefing, patellar tendon splitting and its medial transfer. On the other hand bone procedures on the hypoplastic lateral femoral condyle were also performed by Albee, as well as tibial tubercle transfer and trochleoplasty by deepening of the trochlea (Dejour). An understanding of the pathoanatomic basis is the corner stone for     

Sonographic imaging of the patellofemoral medial joint stabilizing structures: findings in human cadavers

The medial soft-tissue restraints of the patella, specifically the medial patellofemoral ligament and the vastus medialis obliquus muscle, are critical to patellofemoral joint stability. A reliable and inexpensive imaging technique would be clinically useful especially after acute patellar dislocation. The medial patellofemoral ligament and the vastus medialis obliquus muscle were identified in cadaveric dissection. The attachments of the medial patellofemoral ligament to the patella and the adductor tubercle, and the attachments of the vastus medialis obliquus muscle to the adductor magnus tendon, adductor tubercle, and patella were carefully observed. Sonography then was performed on four thawed fresh frozen cadaver knees. After sonographic examination of these structures, the knees were dissected and the structures previously identified by sonography were verified. In all four specimens, these restraints of the patellofemoral joint were identified by sonography based on their imaging characteristics and surrounding bony and soft-tissue landmarks.     

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。     

Distal Disinertion of the Patellar Ligament Combined with Avulsion Fractures at the Medial and Lateral Margins of the Patella a Case Report and an Experimental Study

A 12-year-old boy presented with a proximally retracted patella 5 months after an injury to the left knee. The clinical and radiographic features and the findings at operation led to the conclusion that the original lesion had been a distal disinsertion of the patellar ligament combined with avulsion fractures at the medial and lateral margins of the patella, produced by the medial and lateral longitudinal patellar retinacula. Loading experiments on amputation and cadaver specimens showed that these retinacula, apart from being tendons for the vastus medialis and the vastus lateralis, respectively, constitute a direct fibrous connection of considerable strength between the patella and the tibia and thus are capable of producing avulsion fractures.