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PubMed1987

Lateral retinacular release of the patella.

From October 1977 through January 1984, 2,330 arthroscopic procedures of the knee were performed by one of the authors (G.J.S.). Among these procedures, 35 lateral retinacular releases were performed through minimal, lateral incisions. Twenty-two knees in 22 patients were available for follow-up evaluation, and these cases were reviewed retrospectively. The average age of the patients at the time of surgery was 22.6 years. The average follow-up period was 48 months. The patients were divided into three subgroups on the basis of their preoperative diagnosis. Group I (eight knees) had a history of patellar dislocations; group II (seven knees) had recurrent patellar subluxation, identified by history and physical and radiographic examinations; and group III (seven knees) had patellar pain without a history of dislocations or subluxation and with no symptoms of instability. All of these patients underwent diagnostic arthroscopy and lateral retinacular release, as well as arthroscopic treatment of associated pathology. Postoperatively and at the time of followup, all patients were evaluated for pain, function and patellar instability. In 15 patients with a history of patellar dislocation or subluxation, 67% were found to have had significant improvement in their symptoms, which was borne out by the findings during physical examination. None was worse following treatment. Among the seven patients with no history of patellar dislocation or subluxation, only one of the seven had a satisfactory result. Based upon the findings of this study, it was concluded that arthroscopic lateral retinacular release is a reasonable, initial step in the surgical treatment of patellar dislocation or subluxation, resistant to conservative treatment. Its efficacy in cases of recalcitrant patellar pain without a history of instability is doubtful.

Adolescent↗
PubMed1989

Arthroscopy in the diagnosis of occult dislocation of the patella.

The authors investigated the incidence of acute patellar dislocation by clinical and radiologic examination and by arthroscopy. Acute patellar dislocation represented 2.44% of all knee injuries in their series, and only 25% of the former were evident at the initial examination.

Arthroscopy↗
PubMedDate not supplied

Axial and lateral radiographs in evaluating patellofemoral malalignment.

This is a prospective study of 431 patients (862 knees) with patellofemoral pain, patellar dislocation, or other abnormalities of the knee joint. There were 217 asymptomatic knees with no contralateral problems for comparison. All patients had a history and physical and radiographic examination of both knees. The radiographs included standard anteroposterior views, axial views at 30 degrees of knee flexion, and standing lateral views at 0 degree and 30 degrees of flexion. The presence of patellar tilt or subluxation was noted on the axial view. The lateral view of the patella, with precise overlap of the posterior femoral condyles, allowed determination of relationships between the patella's medial edge, median ridge, and lateral edge to assess patellar tilt. Sixty-two percent of patients with patellar dislocations demonstrated subluxation on the axial view, while 98% demonstrated an abnormal lateral view. Eighteen percent of the control knees revealed evidence of subluxation on the axial view while 35% demonstrated subluxation on the extended lateral view. The axial view demonstrated 62% sensitivity for dislocation, while the lateral view taken in full extension demonstrated 98% sensitivity. The specificity for previous dislocation was 82% for the axial view and 93% for the lateral flexed view. Given the high sensitivity of the lateral view for detecting prior patellar dislocation, a normal result on this view can virtually eliminate the question of previous dislocation. Also, with the high specificity of the axial view and lateral view with knee flexion, the two views combined can confirm a clinical impression of patellofemoral malalignment.

Adolescent↗
PubMed1976

Occult traumatic dislocation of the patella.

In series of patients with clinically established traumatic patellar dislocation other authors have found surgical and radiological lesions pathognomonic for this condition. In a series of patients admitted with hemarthrosis, and with no knowledge of having had dislocation of their patella, we found the same lesions thus illustrating that a syndrome of occult traumatic patellar dislocation exists. The vertical location of the patients' patellae was found normal measured by the index of Insall and Salvati (9). The intercondylar groove measured by the method of Brattström (4) was found in almost all cases to be under the upper normal limit. Their knee caps were normal following the descriptions of Knutsson. None had valgus knees beyond normal upper limits and none had general laxity of joints, thus indicating that this syndrome may be found in normal knees.

Adolescent↗
PubMed2000

"Slip sliding Away": patellofemoral dislocation and tracking.

This article reviews the anatomy of the medial retinacular complex and the relationship of the anatomy to patellar dislocation. Clinical and radiographic findings of patellar dislocation are discussed, and the technical considerations and clinical usefulness of patellar tracking studies are addressed.

Femur↗
PubMed1994

Surgical treatment of recurrent dislocation of the patella.

Sixty-seven patients (69 knees) with recurrent patellar dislocation underwent either a lateral release (20 knees), a proximal realignment (14 knees), a distal realignment (16 knees), or a combined realignment (19 knees) procedure. Average respective followup was 8, 8, 6, and 4 years. Patients undergoing lateral release experienced a 40% recurrence of patellar dislocation. After a realignment procedure, redislocation was uncommon (4%), but pain and swelling were reported by 12% of the patients. Significant patellofemoral crepitation was present in 35% of the realignments. The congruence angle was corrected satisfactorily in the proximal realignments, but it remained abnormal in 25% of the distal realignments. The distance from the tuberosity to the sulcus was restored to normal by transposition of the tibial tuberosity, but remained abnormal in 36% of the proximal realignments. However, it did not preclude a good clinical result. Lateral release cannot be recommended for knees with severe dysplasia of the extensor mechanism. Proximal, distal, and combined realignments yielded similar clinical results. Retensioning of the medial structures and lateral release are effective in reducing the patella within the sulcus. Although transposition of the tuberosity is appealing, clinical advantages are less evident.

Adolescent↗
PubMed1991

[Arthroscopy in acute dislocation of the patella: a new surgical technique].

The adequate treatment for acute patellar dislocation is still controversial. The Authors describe a new surgical arthroscopic technique to repair medial retinaculum rupture, which is the most common lesion in the acute patellar dislocation. Compared to arthrotomy arthroscopic treatment eliminates post-operative pain and shows the same advantages in reducing recurrences.

Acute Disease↗
PubMedDate not supplied

Acute dislocation of the patella. A correlative pathoanatomic study.

The objective of our study was to elucidate the characteristic pathoanatomy associated with patellar dislocation and report the preliminary results of early surgical repair. Twenty-three patients with documented patellar dislocation had standard radiographs and a magnetic resonance imaging scan. Intraarticular lesions were evaluated and treated arthroscopically followed by an open exploration of the medial aspect of the knee in 16 patients. Twelve patients were observed for a minimum of 2 years after surgical repair (average, 34 months). Eleven patients returned for a follow-up examination. Magnetic resonance imaging revealed effusion (100%), tears of the femoral insertion of the medial patellofemoral ligament (87%), increased signal in the vastus medialis muscle (78%), and lateral femoral condyle (87%) and medial patellar (30%) bone bruises. Arthroscopic examination revealed osteochondral lesions involving the patella and the lateral femoral condyle in 68% of cases. Open surgical exploration revealed tears of the medial patellofemoral ligament off the femur in 15 of 16 patients (94%). After medial patellofemoral ligament repair, none of the patients experienced recurrent dislocation. Overall 58% of the results were considered to be good or excellent and 42% were fair. Fifty-eight percent of the group returned to their previous sport with no or minor limitations.

Acute Disease↗
PubMed2005

Antero-medialisation of the tibial tubercle for patellar instability.

We reviewed 19 patients (24 knees) with patellofemoral instability treated surgically with antero-medialisation of the tibial tubercle and lateral retinacular release. Twenty-two knees had recurrent patellar dislocation and two patellar subluxation. Lateral retinacular release was performed arthroscopically in 15 knees. Average follow-up was 52 (16-86) months. There was one postoperative haemarthrosis and one failed fixation, which needed surgical revision. The average Lysholm score improved from 63.3 to 98 and only one knee had persistent patello-femoral pain postoperatively. The patellar tilt angle improved from 9.4 degrees to 5.5 degrees . There were no redislocations. We find that the surgical technique produces a consistent correction of patellar instability, but long-term studies are needed to confirm whether it can prevent arthritic degeneration.

Adolescent↗
PubMedDate not supplied

Semitendinosus tenodesis for repair of recurrent dislocation of the patella in children.

Recurrent dislocation of the patella is more common in girls than in boys. Although several predisposing factors may exist, patellar dislocation is most commonly associated with familial ligamentous laxity. Many surgical repairs have been described to stabilize the patella. We have found the semitendinosus transfer to the patella to result in a predictable, stable patellofemoral joint without risk of injury to the proximal tibial physis. Between January 1990 and December 1997, 29 children have been treated at the Children's Hospital of Eastern Ontario with a semitendinosus transfer for recurrent dislocation of the patella. Seven children were excluded from the study because of insufficient follow-up; consequently this series consisted of 22 children. Four children underwent bilateral repairs, hence 26 knees that have been operated on with this procedure were included in this study. There were three boys and 19 girls, with an average age at surgery of 14 years and 4 months, ranging from 8 years and 11 months to 17 years and 10 months. The average length of follow-up was 3 years and 2 months, ranging between 2 years and 7 years and 4 months. All children had experienced greater than three episodes of recurrent dislocation of the patella. Pain consistent with patellofemoral syndrome or chondromalacia was present in 17 of 26 knees. On clinical examination, 10 knees exhibited marked ligamentous laxity. There were nine positive patellar apprehension tests, and eight patellae were hypermobile. All children were treated with a semitendinosus transfer to the patella with concomitant tightening of the medial retinaculum and a lateral retinacular release. On long-term follow-up, 23 of the 26 knees (88%) were asymptomatic, and the child had returned to regular activities. Each child completed the Lysholm and the subjective component of the Zarins-Rowe questionnaire to determine the subjective results of the repair procedure. Three children complained of patellofemoral symptoms. One child experienced recurrence of the patellar dislocation, and one child developed medical patellar subluxation.

Adolescent↗
PubMed1998

Malrotation causing patellofemoral complications after total knee arthroplasty.

Thirty patients with isolated patellofemoral complications after total knee arthroplasty were compared with 20 patients with well functioning total knee replacements without patellofemoral complications. The epicondylar axis and tibial tubercle were used as references on computed tomography scans to measure quantitatively rotational alignment of the femoral and tibial components. The group with patellofemoral complications had excessive combined (tibial plus femoral) internal component rotation. This excessive combined internal rotation was directly proportional to the severity of the patellofemoral complication. Small amounts of combined internal rotation (1 degree-4 degrees) correlated with lateral tracking and patellar tilting. Moderate combined internal rotation (3 degrees-8 degrees) correlated with patellar subluxation. Large amounts of combined internal rotational (7 degrees-17 degrees) correlated with early patellar dislocation or late patellar prosthesis failure. The control group was in combined external rotation (10 degrees-0 degree). The direct correlation of combined (femoral and tibial) internal component rotation to the severity of the patellofemoral complication suggests that internal component rotation may be the predominant cause of patellofemoral complications in patients with normal axial alignment. The epicondylar axis and tibial tubercle are reproducible landmarks which are visible on computed tomography scans and can be used intraoperatively. Using this computed tomography study can determine wether rotational malalignment is present and thus, whether revision of one or both components may be indicated.

Arthroplasty, Replacement, Knee↗
PubMed2006

[Rotational malalignment causing patellofemoral complications after total knee replacement].

OBJECTIVE: To study the rotation of femoral component and tibial component with CT and evaluate the relationship between patellofemoral complications and rotational alignment of the components. METHODS: Thirty patients with isolated patellofemoral complications after total knee arthroplasty were compared with 20 patients with well functioning total knee replacements free of patellofemoral complications. The epicondylar axis and tibial tubercle were used as references on CT scans to quantify the rotational alignment of the femoral and tibial components. RESULTS: Patients with patellofemoral complications had excessive combined (tibial plus femoral) internal component rotation, which was directly proportional to the severity of the patellofemoral complications. Mild combined internal rotation (1 degree-4 degrees) was correlated with patellar and lateral tracking tilting, moderate rotation (3 degrees-8 degrees) with patellar subluxation, and severe rotation (7 degrees-17 degrees) with early patellar dislocation or late patellar prosthesis failure. The control group had combined external rotation of 10 degrees-0 degree. CONCLUSIONS: The direct correlation of combined internal component rotation to the severity of the patellofemoral complication suggests that internal component rotation may be the predominant cause of patellofemoral complications in patients with normal axis alignment. CT scans can be used intraoperatively and postoperatively to determine whether the rotational malalignment is present to require revision of one or both components.

Adult↗
PubMed1989

Insall proximal realignment for disorders of the patella.

Proximal realignment with standard lateral retinacular release (Insall operation) was performed on 35 knees with a follow-up time of two to 11 years. The results for chondromalacia patellae were satisfactory to excellent results in 20 of 23 knees (87%) at two years and in eight of 15 knees (55%) at five to 11 years. Satisfactory to excellent results in 11 of 12 knees (92%) were noted for recurrent patellar dislocation. This procedure should be reserved for advanced chondromalacia patellae (Grades III and IV) and recurrent patellar dislocation. Anatomic studies suggest that the pain relief was most likely due to a combination of patellar denervation and restoration of patellar congruence.

Adult↗
PubMed2004

Indications in the treatment of patellar instability.

Recent developments in patellar instability have focused on the passive restraints against mediolateral patellar motion. Viewed from this perspective, muscle alignment is considered secondary because, although muscle forces are important, their ability to cause or prevent patellar dislocation depends on passive stability or the lack thereof. In the normal knee, the patella seats quickly in the trochlea in early flexion, so that the ligamentous restraints are important only near full extension. In the unstable patellofemoral joint, the trochlea frequently is deficient and patella alta often exists. In such cases, the ligaments assume a greater role in preventing excessive lateral patellar displacement. The most pressing questions at the moment are: 1) which of the anatomical abnormalities must be corrected, alone or in combination, to prevent further patellar instability; and 2) what is the relative risk of corrective procedures compared to the natural history or competing surgical approaches? These questions must be addressed by clinical trials. Only a minority of patients who experience patellar dislocation will redislocate the patella, and surgical treatment does not always yield results that are superior to conservative care. Treatment recommendations should be based on an individual's risk of recurrent dislocation, pain, and disability, a thorough understanding of his or her anatomy, and clear treatment objectives. Lateral release has no role in the treatment of a hyperlax patellofemoral joint, as it adds additional laxity to a system that is already unstable. If surgery is performed, current evidence suggests techniques aimed at repair or reconstruction of the passive retinacular restraints are as effective as more extensive procedures at preventing subsequent dislocations. Among the latter procedures, realignment procedures use active muscle forces to help seat the patella in the femoral groove; however, biomechanical costs are associated with this approach and superior results have not been demonstrated with distal and combined realignments compared with more limited proximal procedures.

Adolescent↗
PubMed2005

Trochleoplasty in dysplastic knee trochlea.

In patients complaining of recurrent patellar dislocations or persistent retropatellar pain due to a dysplastic femoral trochlea, we perform a Henri Dejour trochleoplasty. In this technique the femoral trochlea is deepened by removing the subchondral trochlear bone followed by incision, impaction and fixation of the cartilage flange along the trochlear groove. Between 1996 and 1999, 13 procedures were performed in 12 patients. Strictly lateral X-rays showed dysplasia of the trochlea, as defined by the "crossing sign", whether or not in combination with patella alta. Patients were assessed using the Larsen-Lauridsen score considering pain, stiffness, osteopatellar crepitus, flexion and loss of function. Although the majority of patients scored fair and poor on an objective scoring system, we achieved 77% good to very good subjective results. Although the result was not perfect, the patients were satisfied with the procedure. This technique might be a valuable alternative in cases of frank trochlear dysplasia associated with persistent retropatellar pain or recurrent patellar dislocations.

Adolescent↗
PubMedDate not supplied

Medial patellofemoral ligament injury following acute transient dislocation of the patella: MR findings with surgical correlation in 14 patients.

PURPOSE: The purpose of this study was to determine the accuracy of MRI in determining both the extent and the location of injury to the medial patellofemoral ligament (MPFL). METHOD: MR findings were compared to the surgical results of 14 consecutive patients who experienced transient patellar dislocation. Two musculoskeletal radiologists, blinded to the surgical results, retrospectively reviewed the MR studies, and a consensus reading was obtained. RESULTS: Surgery demonstrated complete disruption of the MPFL in 7 of 14 patients (50%), with stretching or partial tearing of the MPFL in the remaining 7 (50%) patients. MRI was 85% sensitive and 70% accurate in detecting MPFL disruption. Vastus medialis obliquus muscle elevation was present in 12 of 14 (85%). CONCLUSION: MRI accurately depicts both the extent and the location of MPFL injury following transient patellar dislocation and can therefore play a significant role in directing surgical management of these patients.

Acute Disease↗
PubMedDate not supplied

Use of a modified Elmslie-Trillat procedure to improve abnormal patellar congruence angle.

Forty patients underwent 45 modified Elmslie-Trillat realignment procedures (mean followup, 2 years) for refractory patellar instability (34 knees) or painful patellofemoral syndrome with malalignment (11 knees). The postoperative congruence angle (mean, +3.4 degrees) was significantly improved compared with the preoperative value (mean, +21.5 degrees). We considered the "normal" congruence angle average as -8 degrees (range, -20 degrees to +4 degrees). Over time postoperatively, we detected no statistical difference in the congruence angle (5 months, 3.4 degrees; 24 months, 6.3 degrees). There were no patellar dislocations postoperatively. Nine knees (20%) had some postoperative subluxation. Ninety-four percent of the patients without subluxation had congruence angles less than 15 degrees, whereas 54% of patients with postoperative subluxation had postoperative congruence angles greater than 15 degrees. The evidence in this study population indicates that the modified Elmslie-Trillat procedure can predictably improve the patellar congruence angle. Adequate correction may eliminate patellar dislocation. Correction of the congruence angle to less than +15 degrees will result in a decreased incidence of postoperative patellar instability. Early full activity postoperatively did not affect the modified Elmslie-Trillat correction of the congruence angle being maintained over time.

Adolescent↗
PubMed2001

[The origin of femoral trochlear dysplasia: comparative anatomy, evolution, and growth of the patellofemoral joint].

We performed a comparative analysis of the femoropatellar morphology examining the evolutionary aspects to search for the origin of trochelar dysplasia. Trochlear dysplasia is frequent in the human population and, when associated with morphological and positional abnormalities of the patella, can lead to patellar pain syndrome in minor cases or patellar dislocation in severe cases. There is no strict relationship between the observed anomalies and clinical expression. The shape of the articular surfaces is variable in mammals depending on their type of locomotion: unguligrade, digitigrade, plantigrade. In greater apes, the femoral diaphysis is straight and the trochlea is flat and symmetrical. The patella does not tend to dislocate laterally since the knee under load is always flexed. In human adults, the femoral diaphysis has a valgus obliquity angle of 8 degrees to 10 degrees. Consequently, the trochlea has a deepened sulcus and an elevated lateral lip, avoiding lateral patellar dislocation, especially during initial knee flexion. In the human newborn, the femoral diaphysis is vertical. As the child starts walking, the femoral obliquity angle develops between 1 and 7 years of age, inducing a secondary valgus of the extensor apparatus. This obliquity does not develop in non-walking children. Fossil femurs of australopithecus demonstrate that a high obliquity angle had appeared more than 3 million years ago, but also exhibit a poorly deepened trochlea and a slight elevation of the lateral facet. At 1.8 million years, the fossils have the oblique diaphysis, the strongly deepened sulcus and the strongly elevated lateral facet. The obliquity angle of the femoral diaphysis is the leading feature which initiated the later modifications of the patellofemoral joint that over 3 million years were never inscribed in the human genoma. Lateral trochleal lip and deep sulcus are features that were first acquired, then once selected, genetically assimilated, and now appear on the fetal cartilaginous epiphysis.

Adult↗