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Medium-term results of the operative treatment of recurrent patellar dislocation by Insall proximal realignment.

Between 1984 and 1991, 36 patients with the diagnosis of recurrent patellar dislocation were treated operatively using the proximal realignment procedure. Thirty patients were available for follow-up. The average follow-up period was 6.3 years (range 2-9.6 years). The average age at injury was 21.3 years with a predominance of female patients. At follow-up all knees were physically examined. The results were evaluated using the score of Larsen and Lauridsen as well as the Tegner score and subjective assessment. Radiographs from 19 patients (63%) were available for review. At follow-up one patient suffered from a recurrence of patellar dislocation. All patients had stable knee joints and a full range of motion. There was no statistically significant difference between pre- and postoperative sports activity level. Seven patients (23.3%) had excellent results, 12 patients (39.9%) good results and 1 a poor result using the Larsen and Lauridsen score. Subjective assessment revealed the operative result as very good, good or satisfactory in 90%. Patellofemoral osteoarthritis was seen in 7 of 19 patients (36.8%). With a proximal realignment procedure good clinical results can be achieved for recurrent patellar dislocation. Subjective satisfaction with this procedure is rated as good. It is successful in preventing redislocation.

Adolescent↗

Delayed proximal repair and distal realignment after patellar dislocation.

Twenty athletes with distal malalignment who sustained unilateral traumatic patellar dislocation remained impaired by chronic instability. Surgery was performed at a mean age of 18 years. Posttraumatic attenuation of the medial patellofemoral ligament was repaired near the margin of the patella in 10 knees and avulsion or attenuation posterior to the vastus medialis obliquus in 10 knees. Advancement of the medial patellomeniscal ligament at the margin of the patella and normalization of the Q angle to 10 degrees by tibial tubercle osteotomy were performed in each knee. Distal lateral retinacular release without release of the normal vastus lateralis tendon was performed. Results were judged according to Turba et al, and activity levels were evaluated per guidelines of the International Knee Documentation Committee. Eighteen (90%) patients achieved good or excellent results and were unimpaired at a minimum of 24 months. Two patients achieved fair subjective results with some impairment in vigorous activity. There was no recurrent instability. Radiographically, the mean preoperative patellofemoral congruence angle improved from 20 degrees to 0 degree. Athletes who sustain an initial traumatic patellar dislocation after physeal closure and in whom conservative management fails can be treated successfully by repair of the medial patellofemoral ligament at the site of disruption and advancement of the medial patellomeniscal ligament combined with correction of an elevated Q angle.

Adolescent↗

Vertical patellar dislocation: a case report.

The purpose of this case report is to highlight an unusual diagnosis and mechanism of injury. Vertical patellar dislocation is an uncommon entity. Relatively few cases have been reported in the literature, and most of these have occurred in adolescent boys who have sustained a direct blow to the knee while engaging in some form of contact sport. The case reported here is a vertical patellar dislocation that happened to a 10-year-old girl without any trauma. This is an unusual case and seemingly atypical for a vertical patellar dislocation. The knowledge of this diagnosis might assist clinicians in the understanding of unlikely mechanisms of injury in the assessment and treatment of this musculoskeletal disorder.

Child↗

Arthroscopic treatment of acute patellar dislocations.

Twenty-nine patients treated with arthroscopy alone for acute patellar dislocation were reviewed. All had a significant traumatic episode with hemarthrosis in a previously asymptomatic knee. Clinical follow-up averaged 25 months (range 5-64 months). Fifteen patients had concomitant percutaneous lateral release (LR). Significant-sized osteochondral defects not radiographically visible preoperatively were discovered in 40%. Fragments were excised and corresponding craters debrided or abraded. Additional intraarticular pathology discovered included two meniscal tears and one anterior cruciate tear. Overall excellent (E) and good (G) results were 83%. The recurrence rate was 14%, all of which occurred in the LR group. All recurrent dislocations occurred within 1-year post injury. The LR group had 73% G and E results compared with 93% in those without LR. Arthroscopy followed by immobilization was an efficacious approach to acute traumatic patellar dislocations in this specific group of patients. The addition of LR with early motion, however, detracted from the results.

Acute Disease↗

Acute patellar dislocations. The natural history.

Of 27 patients sustaining primary patellar dislocations, 20 were treated with immobilization and subsequent physiotherapy (including nine patients who underwent arthroscopy) and seven with immediate surgical stabilization and lateral release. The patients with predisposing factors such as patellofemoral malalignment, abnormal patellar configuration, and a history of prior symptoms of instability were more prone to recurrent dislocation and may benefit from operative intervention. Although the incidence of recurrence among those individuals can be decreased, at least 30% to 50% of all patients having sustained a primary patellar dislocation will continue to have symptoms of instability and/or anterior knee pain.

Acute Disease↗

[Resorbable pin refixation of an osteochondral fracture of the lateral femoral condyle due to traumatic patellar dislocation: case management, follow-up and strategy in adolescents].

AIM: Intraarticular osteochondral fractures resulting from traumatic patellar dislocation in children are reported most frequently between 13 and 15 years of age. Fracture localization concerns, apart from loose intraarticular bodies, the inferiomedial patellar facet and the lateral femoral condyle. Osteochondral fractures of the lateral femoral condyle with more than 50 % of its surface are extremely rare and reported infrequently. METHOD: We report a traumatic patellar dislocation in a 14 year old patient that let to an osteochondral fracture of the lateral femoral condyle. MRI-scan demonstrated an extensive fracture size concerning more than 50 % of the condylar surface with intraarticular dislocation. Initially arthroscopic surgery followed an open reduction and internal refixation of the osteochondral fragment with resorbable, poly-p-dioxanon pins. RESULTS: Follow-up MRI-scan revealed 7 weeks after surgery an adequate repositioning of the fragment with correct pin placement. Second-look arthroscopy demonstrated an osteochondral reintegration of the fragment within a period of 7 months after prior surgery. CONCLUSION: Resorbable poly-p-dioxanon pins as a mean for refixation of an osteochondral, intraarticular fracture in an adolescent, with an arthroscopic confirmed acceptable result, seem to be a considerable therapy option.

Absorbable Implants↗

Treatment of acute patellar dislocation.

To determine the effectiveness of nonoperative and operative treatment of initial acute patellar dislocation, we reviewed the charts of 399 patients with the diagnosis of an acute dislocation, seen during a 30 year period. One hundred patients (103 knees) met the criteria for inclusion in the study. The average age of the patient at injury was 21.7 years (range, 9 to 72 years). Length of followup averaged 8 years (range, 2 to 26 years). Retrospectively, we divided the patients into two groups, according to the examination of their unaffected knee. Group I (69 knees) showed evidence on examination of congenital abnormality of the extensor mechanism in the unaffected knee, indicating a predisposition to dislocate with less significant trauma. Group II (34 knees) showed no clinically perceptible congenital predisposition to dislocate based on examination of the unaffected knee. In the nonoperatively treated knees in Group I, there was a 52% (28/54) incidence of good or excellent results. The nonoperatively treated knees in Group II had a 75% (15/20) incidence of good or excellent results. Acute dislocation occurred more frequently in males than in females. Recurrence was rarer in patients whose initial dislocation had occurred when they were over 15 years old. Contrary to recently published reports, primary acute traumatic patellar dislocations can be treated with nonoperative therapy with good or excellent results. Initial evaluation should include examination of the uninvolved knee which, if found to have signs of congenital abnormality, would indicate a worse prognosis.

Adolescent↗

Rotational knee strain resulting in patellar dislocation. An experimental study in rabbits.

The right lower extremities of 64 young rabbits were immobilized by a plaster spica. The animals developed a gait pattern, which included internal tibial rotation and adduction of the left (unimmobilized) tibia. Twenty-one of the animals developed medial patellar dislocation in the unimmobilized lower extremity. The mechanism of the patellar dislocation in this experimental model was possibly overstretching of the lateral colateral ligament and the lateral side of the joint capsule, associated with medial rotation of the tibia and the tibial tubercle. The direction of patellar pull when gliding inferiorly during knee flexion was shifted medially, resulting in patellar dislocation and secondarily, in formation of an exostosis under the displaced patella. Hip arthrodesis in humans, as a course of rotational instability of the contralateral knee, resembles some aspects of this experimental condition.

Animals↗

Patellar dislocation in Kabuki syndrome.

We describe four individuals (two females and two males) with Kabuki syndrome and recurrent dislocation of the patella. The age of diagnosis of patellar dislocation ranged from 11 to 23 years. One individual underwent excision of the free fragment and transfer of the tibial tuberosity with good outcome. Two required patellar brace for instability. Characteristics of individuals with the syndrome at a high risk of patellar dislocation include female, adolescence or young adulthood, joint laxity, and obesity.

Abnormalities, Multiple↗

Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury.

We prospectively studied the characteristics and early recovery of an unselected population of patients who had acute first-time lateral patellar dislocation. The recovery program used standardized rehabilitation, emphasizing range of motion, muscle strength, and return of function. Patients returned to stressful activities including sports as tolerated when they regained full passive range of motion, had no effusion, and when quadriceps muscle strength was at least 80% compared with the noninjured limb. Seventy-four patients met the enrollment criteria; 37 men and 37 women. The average age was 19.9 years, and preinjury sports participation was similar to that of ligament-injury patients. Four percent of patients (N = 3) had a history of birth complications, 3% (N = 2) had a history of lower extremity problems as an infant or child, and 9% (N = 7) had a family history of patellar dislocation. Radiographs revealed a 50% incidence (N = 37) of patella alta; all patients demonstrated lateral patellar overhang. Patients regained range of motion (mean, 0 degrees to 132 degrees) by 6 weeks. Sports participation remained significantly reduced throughout the first 6 months after injury, with the greatest limitations in kneeling and squatting. At 6 months, 58% of patients (N = 43) noted limitation in strenuous activities. The patients who had acute primary patellar dislocation were young and active. Most injuries occurred during sports, and few patients had abnormal physical features, contradicting any stereotype of an overweight, sedentary, adolescent girl whose patella dislocates with little or no trauma.

Adolescent↗

Traumatic patellar dislocation in children and adolescents: treatment update and literature review.

PURPOSE OF REVIEW: Traumatic patellar dislocation in children and adolescents is a complex problem resulting from a range of anatomic and mechanical conditions. A careful review of the literature demonstrates certain risk factors that predispose children to recurrent dislocation. With this understanding, these conditions can be managed more aggressively in the hope of an improved outcome. Additionally, a vast number of surgical procedures to correct patellar instability have been described, and recent cadaveric studies are now guiding surgical interventions. RECENT FINDINGS: Risk factors for recurrent dislocation may include various skeletal abnormalities, increased quadriceps angle, generalized ligamentous laxity, and family history. Recent anatomic and biomechanical studies have demonstrated that the medial patellofemoral ligament and the vastus medialis obliquus are the primary restraints to lateral translation and ultimately dislocation of the patella. Management should therefore be directed both at correcting anatomic abnormalities when indicated and at reconstruction of medial restraints to patellar tracking. SUMMARY: The recommendation for management of a traumatic patellar dislocation in a skeletally immature patient is initially conservative, emphasizing early motion and quadriceps strengthening. However, in patients for whom conservative management has failed or who are at particularly high risk for dislocation and require surgical intervention, repair or reconstruction of the medial patellofemoral ligament is the treatment of choice. Recent works have included investigation of less invasive techniques in children.

Adolescent↗

Functional treatment of patellar dislocation in an athletic population.

Fifty-eight athletically active study participants with 69 knees that had experienced patellar dislocations were available for followup after being selected for a functional rehabilitation program without antecedent immobilization. Follow-up evaluation was at a minimum of 24 months after onset of treatment and averaged 46.2 months. Good or excellent results occurred in 39 (66%) knees treated after an initial patellar dislocation and in 15 (50%) knees with a chronic history of patellar instability. Twenty-six percent of the 69 knees had experienced recurrent patellar instability at followup. Overall, 42 patients (73%) were satisfied with their knees after this nonsurgical management. Anatomic predisposition and onset of bilateral instability at an early age were found to be significant factors associated with a less favorable outcome.

Adolescent↗

External tibial torsion: an underrecognized cause of recurrent patellar dislocation.

Seventeen patients (18 knees) with recurrent patellar dislocation were identified with increased quadriceps angles secondary to excessive isolated external tibial torsion. Traditional realignment procedures attempted in these knees were unsuccessful because of failure to align the biomechanical axis of the extensor mechanism. Derotational osteotomies of the tibia just proximal to the patella tendon insertion were used to reduce the quadriceps angle to within normal limits to improve the biomechanics of the extensor mechanism. Seventeen (94%) knees were available for clinical and subjective followup at an average of 25 months (range, 1-3.2 years). Overall, 13 of the 17 knees were graded as good to excellent (76%). Five of the 17 patients also had well established anterior knee pain in addition to recurrent dislocation and were treated with a combined derotational and Maquet type osteotomy, with 4 patients obtaining a good to excellent result. Knees that subjectively and functionally demonstrated less painful symptoms preoperatively were associated with excellent results. Poor outcomes were associated with knees that were operated on multiple times.

Adolescent↗

[Current aspects of surgical management of patellar dislocation in the growth period with special reference to Goldthwait surgery].

RESEARCH QUESTION: The Goldthwait procedure is an operative treatment method for patellar dislocation in children which respects the growth plate. The aim of the study was to analyse the long term results of this procedure. METHODS: The results of 36 knees (26 children) operated on because of patellar dislocation according to the Goldthwait technique alone or in combination with other procedures (Krogius, patellar fixation) between 1941-1991 at Balgrist Clinic were analysed. Therefore, we used an own score. RESULTS: After a mean follow-up of 16 years (1.5 to 51 years) we found in 77.8% of the cases good and very good subjective results, and in 63.9% good and very good objective results. A recurrence of dislocation occurred in 36.1% of the cases. In 76.9% of these cases a reoperation was performed, of which only one case led to an acceptable final result. The operation results were unsatisfactory in the presence of condylar dysplasia with an angle of more than 160 degrees. The age at the time of surgery and the degree of patellar dysplasia had no effect on the outcome. The success was increased through the use of the Goldthwait procedure in conjunction with other techniques. Pathologic leg axis or severe arthrosis did not occur. CONCLUSION: In absence of significant condylar dysplasia the Goldthwait procedure combined with other techniques provides acceptable results. The technique alone is less efficient.

Adolescent↗

Patellofemoral relationships and distal insertion of the vastus medialis muscle: a magnetic resonance imaging study in nonsymptomatic subjects and in patients with patellar dislocation.

The correlation between the insertion level of the vastus medialis muscle and lateral patellofemoral angle (LPA), lateral patellar displacement (LPD) and tilt (LPT), and the height of the patella (LT/LP) was analyzed by magnetic resonance imaging (MRI) in patients with patellar dislocation (n = 10) and in control subjects (n = 10). Images were produced in 0 degrees and 20 degrees of knee flexion. The insertion level to the patella was also analyzed with the knee in extension. No significant correlation was noted between the insertion level and different patellofemoral indexes, but multiple-regression analysis showed that the best predictor for the insertion level was the LPA with the knee in extension. The insertion level was significantly more proximal in patients with patellar dislocations than in normal subjects.

Adolescent↗

Locked patellar dislocation with vertical axis rotation. A case report.

Whereas traumatic lateral dislocation of the patella is a well-described clinical entity, other types of patellar dislocations, specifically those that involve patellar rotation, are unusual. These rare types also present a therapeutic problem in which reduction often requires a general anesthetic and, possibly, an open procedure. A 16-year-old boy sustained a laterally directed blow to his knee, resulting in dislocation of the patella. The patella had rotated 90 degrees in the vertical plane and became wedged against the lateral femoral condyle. Initial attempts at closed reduction in the emergency room and under general anesthesia in the operating room were unsuccessful, and the patient required open reduction. A similar type of dislocation has been described; however, the patella is usually intercondylar. The tear along the medial side was extensive enough to allow the patella to dislocate lateral to the lateral femoral condyle, making this a unique case. In these instances of rare patellar dislocation, the surgeon should be prepared to perform an open reduction, because attempts at closed reduction even with a general anesthetic may be unsuccessful.

Adolescent↗

[Patellar dislocation as a cause of osteochondral fracture of the femoro-patellar joint].

Acute traumatic dislocation of the patella may be associated with osteochondral fractures. Clinical examination invariably shows a tense effusion. A detailed radiographic examination including antero-posterior, lateral and skyline views of the patella is usually necessary to establish an exact diagnosis. Once diagnosis is made open reduction and fixation of the osteochondral fracture should be carried out if it is possible. Out of 78 patients of our own with patella dislocation 24 cases suffered an osteochondral fracture. In ten cases refixation of the osteochondral fragment was achieved. Intraoperatively the alignment of the patella was controlled in any case. In cases of lateral subluxation lateral release and medial reconstruction was performed. In two cases medial transfer of the tibial tuberosity was carried out. Osteochondral fractures of the femoro-patellar groove represent an important injury in the course of acute patellar dislocation. With exact diagnosis and correct treatment congruity of the femoro-patellar joint can be restored in many cases.

Bone Transplantation↗