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PubMedDate not supplied

Articular hypermobility and chondral injury in patients with acute patellar dislocation.

Thirty adolescents with acute, primary patellar dislocation were assessed for a relationship between articular hypermobility and chondral injury. The 15 patients without articular hypermobility had a 2.5 times increased frequency of articular lesions when compared with 15 patients with hypermobility. Assessment of articular hypermobility should be part of the examination in patients with patellar dislocation.

Acute Disease↗

PubMed2003

Total knee arthroplasty for neglected permanent post-traumatic patellar dislocation--case report.

Permanent post-traumatic patellar dislocation is a rare entity resulting from recurrent trauma. This uncommon condition is often confused clinically with congenital dislocation of the patella. Treatment options, although not well defined, include observation, various soft tissue and bony procedures for realigning the patella and patellectomy. To our knowledge, this is the first case reporting the use of conventional non-constrained total knee arthroplasty with patellar resurfacing and soft tissue realignment procedure for long-standing patellar dislocation in a single stage. An interesting feature of this case was the patient's ability to function reasonably well for nearly 40 years with a dislocated patella until the development of secondary osteoarthritis, and the surprisingly good recovery after total knee replacement.

Arthrography↗

PubMed1997

Patellar dislocation in Rubenstein-Taybi syndrome.

This report describes 11 patients with Rubinstein-Taybi syndrome (RTS) and patellar dislocation. The age at diagnosis of patellar dislocation ranged from birth to 16 years. Ten patients had chronic dislocations and 8 of 11 had bilateral patellar dislocations. Eight patients required surgical stabilization of the patella; most achieved a good outcome with surgical repair. All families reported that the patellar dislocations impaired developmental skills which improved after surgery. Seven of the 11 patients were described as having other joint abnormalities including congenital dislocations and laxity of the joints. Patients with RTS should undergo regular thorough joint examinations, including the knees, because abnormalities may result in delay of attainment of motor skills.

Adult↗

PubMedDate not supplied

Surgical technique and rationale for medial patellofemoral ligament reconstruction for recurrent patellar dislocation.

This article describes a medial patellofemoral ligament (MPFL) reconstruction procedure using an artificial ligament for recurrent patellar dislocation. The MPFL has been shown biomechanically to be the primary restraint among the medial patellar stabilizers. Although various predisposing factors are involved in lateral patellar dislocation, we believe that the MPFL, as a primary restraint, should undergo primary reconstruction for patellar dislocation. The results of MPFL reconstruction using a mesh-type artificial ligament and medial retinaculum slip coverage for recurrent patellar dislocation were as good as we had expected. In this article, we describe the detailed surgical technique and its rationale. We believe technique has also wide applications in MPFL reconstruction using autogenous tendons.

Arthroscopy↗

PubMed2002

Patellar dislocation in army conscripts.

Between 1990 and 1996, 119 Finnish male conscripts underwent operative treatment for patellar dislocation. There were 68 conscripts (58%) with primary and 51 conscripts (42%) with recurrent patellar dislocation. Sixty-five (55%) dislocations occurred during military service, 40 (34%) occurred during sports activities, and 14 (11%) occurred during leisure time. The most common cause of injury was military training at battle exercises (n = 30). The typical injury mechanism was knee valgus rotation on fixed foot and tibia (97 conscripts, 82%). Surgical procedures performed were open in 75 conscripts (63%) and arthroscopically assisted in 44 conscripts (37%). Twenty-three (19%) redislocations occurred during follow-up (mean, 6 years; range, 3-9 years). The subjective outcome of treatment was excellent in 23 (19%), good in 42 (35%), moderate in 44 (37%), and poor in 10 (9%) conscripts. The most common residual complaint was patellofemoral pain (25 conscripts, 21%). Only 42 (35%) conscripts were able to finish their military service normally; fitness classification was decreased in 16 conscripts (13%), and 61 (52%) were temporarily exempted from military service (class E). The results of operative treatment did not differ significantly in conscripts with primary and recurrent dislocation, except for the time of first recurrence, which was significantly longer in conscripts with primary than with recurrent dislocation (27 versus 9 months). Patellar dislocation is the most common form of severe knee injury among conscripts and significantly hampers military service. Operative treatment yields only satisfactory results. Preventive measurements should be considered. A suggested algorithm for the treatment and classification of acute and recurrent patellar dislocation among military conscripts is presented.

Acute Disease↗

PubMed2006

MRI of traumatic patellar dislocation in children.

BACKGROUND: Traumatic patellar dislocations (TPD) are common injuries in children, and MRI is useful in evaluation of pediatric musculoskeletal injuries. However, no pediatric studies on the MR features of TPD have been reported. OBJECTIVE: To review the injuries after TPD in children. MATERIALS AND METHODS: Patients with clinical or radiological recognition of TPD and those with suggestive MR findings were selected. Bone, cartilage and soft-tissue injuries and patellofemoral relationships were assessed. RESULTS: A total of 26 patients (age range 10-18 years) were identified. The following injuries were seen: bone bruising of the inferomedial patella (81% of patients) and the lateral femoral condyle (81% of patients), cartilage injuries of the inferomedial patella (38% of patients) and the lateral femoral condyle (38% of patients), osteochondral fragments (42% of patients) and injuries of the medial patellar restraints (81% of patients). CONCLUSION: Pediatric manifestations of TPD seen on MRI are similar to those in adults. TPD is often occult in children. Early recognition of bone bruising of the patella and lateral femoral condyle, associated osteochondral injuries, and medial patellar stabilizer injury is important for timely diagnosis.

Adolescent↗

PubMed2002

Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella.

PURPOSE: To assess magnetic resonance (MR) imaging findings after acute lateral patellar dislocation (LPD) with emphasis on the medial patella restraints and to describe a medial patellar impaction deformity. MATERIALS AND METHODS: Knee MR images obtained within 8 weeks after LPD were evaluated for medial retinacular and medial patellofemoral ligament (MPFL) disruption, vastus medialis obliquus (VMO) edema and/or elevation, and other derangements. One hundred patients with no evidence of prior LPD were evaluated as controls. The Student t test was used for statistical comparisons. RESULTS: Eighty-two examinations were performed in 81 patients with LPD (mean age, 20 years; age range, 9-57 years). Seventy-six percent (62 of 82 examinations) showed medial retinacular disruption at its patellar insertion; 30% (25 of 82), at its midsubstance. The MPFL femoral origin was identified in 87% (71 of 82); of these, 49% (35 of 71) showed injury. Forty-eight percent (39 of 82) showed more than one site of injury to the medial stabilizers; 45% (37 of 82) showed edema or hemorrhage at the inferior VMO. Mean VMO elevation in the coronal plane of the adductor tendon was 2.2 cm, with a range of 0.6-4.5 cm (in control subjects, 0.9 cm; range, 0.1-2.5 cm; P <.001). At the inferomedial patella, 70% (57 of 82) of LPD examinations showed osteochondral injury and 44% (36 of 82) showed concave impaction deformity (0 of 100 control subjects). Other examination findings in LPDs included contusions of the lateral femoral condyle (66 [80%] of 82 examinations) or medial patella (50 [61%] of 82), intraarticular bodies (12 [15%] of 82), effusion (45 [55%] of 82), medial collateral injury (nine [11%] of 82), and meniscal tear (nine [11%] of 82). CONCLUSION: Injury to the medial retinaculum, MPFL, and VMO may be identified at MR imaging after acute LPD. Concave impaction deformity of the inferomedial patella is a specific sign of prior LPD.

Adult↗

PubMed2006

Arthroscopic release of the vastus lateralis tendon for recurrent patellar dislocation.

BACKGROUND: Arthroscopic release of the vastus lateralis tendon for treatment of recurrent patellar dislocation has been criticized on the grounds that it may weaken the quadriceps. HYPOTHESIS: Quadriceps strength and outcome measures improve after arthroscopic release of the vastus lateralis tendon in patients with documented patellar dislocation. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty patients who had recurrent patellar dislocation underwent arthroscopic lateral retinacular release that included a complete release of the vastus lateralis tendon from the superior pole of the patella and were observed prospectively. Bilateral quadriceps strength was tested preoperatively and at follow-up with an isokinetic dynamometer. Patients also completed the International Knee Documentation Committee Subjective Knee Form and the Short Form-36 preoperatively and postoperatively. RESULTS: Follow-up averaged 27 months (range, 24-43 months). There were no redislocations. Mean quadriceps strength improved by a mean of 28% (from 32.3 to 41.4 N x m). The mean quadriceps torque ratio (involved/uninvolved) improved significantly from a preoperative value of 63% (31/51 N x m) to 80% (42/52 N x m) at follow-up (P = .017). Fourteen patients (70%) increased quadriceps torque, and 6 patients (30%) decreased quadriceps torque. Only 1 patient failed to improve on International Knee Documentation Committee and Short Form-36 scores. The International Knee Documentation Committee scores improved from 45 points preoperatively to 76 points at follow-up (P = .001). The Short Form-36 physical component summary scores improved from 38 points preoperatively to 50 points at follow-up (P = .007), and the Short Form-36 physical functioning subscale scores improved from 53 points to 86 points (P = .015). CONCLUSION: Arthroscopic release of the vastus lateralis tendon and lateral patellar retinaculum in patients with recurrent patellar dislocation can improve quadriceps strength and knee function.

Adolescent↗

PubMed2005

Acute traumatic primary patellar dislocation: long-term results comparing conservative and surgical treatment.

OBJECTIVE: This report evaluates the subjective, clinical, and functional long-term results comparing surgical and conservative treatment in patients with a primary traumatic patellar dislocation. DESIGN AND SETTING: This retrospective clinical study focuses on patients with primary acute traumatic patellar dislocation. Patients with radiologic signs indicative of a predisposition for recurrent patellar instability were excluded from this study. PATIENTS: A total of 126 patients were examined a mean of 8.1 years after initial treatment of their primary patellar dislocation. INTERVENTIONS AND MAIN OUTCOME MEASUREMENTS: Patients were retrospectively divided into groups with conservative therapy (n = 63), diagnostic arthroscopy only (n = 20), immediate surgical reconstruction of the parapatellar ligament complex (n = 37), and refixation of osteochondral fragments (n = 6). Redislocation and resurgery rate, activity level, and subjective, clinical, and functional results were evaluated in these patients, and the outcomes in these groups were compared. RESULTS: In the long term, functional results (as expressed in the Lysholm score) were excellent or good in 85% of the patients, and good subjective results were reported by 71%, but follow-up revealed a recurrence rate of 26% in the total study population. The high activity level before the initial trauma could not be completely regained after treatment. There was no significant difference between the surgically and conservatively treated groups in the redislocation and reoperation rates, level of activity, or functional and subjective outcomes. CONCLUSIONS: Even with a focus on acute traumatic etiology and when factors predisposing to recurrent instability are largely excluded, the redislocation rate after treatment of acute patellar dislocation is still high, despite good clinical and subjective results. Conservative management seems to be the treatment of choice in patients with acute patellar dislocation, provided that the generally accepted indications for surgery, such as evidence of osteochondral fragments and major defects of the parapatellar ligament complex, are given due consideration.

Adolescent↗

PubMed1993

Prior lateral patellar dislocation: MR imaging findings.

PURPOSE: To illustrate the constellation of magnetic resonance (MR) findings that suggest prior patellar dislocation. MATERIALS AND METHODS: A computer search of all MR examinations of the knee with a coded diagnosis of patellar dislocation performed between February 1988 and October 1990 disclosed 22 cases (11 male and 11 female patients, aged 1-70 years). RESULTS: Eighteen cases (82%) demonstrated hemarthrosis, medical retinacular disruption, and contusion of the lateral femoral condyle. In 11 cases, the patella was displaced from the trochlear sulcus, but in no patient was there complete dislocation at the time of imaging. Axial short-inversion-time inversion-recovery (STIR) images demonstrated subtle subchondral and cancellous signal intensity abnormalities that were often poorly appreciated on T2-weighted images. In 11 cases, patellar dislocation was not suspected before MR imaging. CONCLUSION: Hemarthrosis, medial patellar and lateral femoral contusion, and retinacular disruption suggest prior lateral patellar dislocation. Because of its sensitivity to subtle intraosseous signal abnormality, axial STIR imaging is a valuable adjunct in the evaluation of the acutely injured knee.

Contusions↗

PubMed1985

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.

Arthritis, Rheumatoid↗

PubMed1978

Acute patellar dislocation: results of immediate surgical repair.

Seventeen cases of acute, first time, lateral patellar dislocations without fracture treated by immediate surgical repair were reviewed and evaluated. Nine patellar tendon realignments and 8 medial side reefing procedures were performed. There were no recurrences of patellar dislocation. Twelve knees were painful, of which 8 were rarely painful. All but one patient were satisfied with their results and participated in any desired sport. Surgical repair of acute patellar dislocation is advocated in the young patient who anticipates future participation in athletics.

Acute Disease↗

PubMed2002

Locked lateral patellar dislocation with impaction fracture of patella.

Irreducible lateral patellar dislocation is rare. It has previously been described with rotation around a vertical axis. We describe a case of irreducible lateral patellar dislocation in a 66-year-old lady with an impaction fracture of medial facet of patella locked on the lateral femoral condyle. Closed reduction was unsuccessful and the patient was treated by total knee replacement. Such a case has not been described previously in the literature.

Aged↗

PubMedDate not supplied

The cartilaginous femoral sulcus in children with patellar dislocation: an ultrasonographic study.

One hundred and sixteen knees of 33 patients with patellar dislocation and 25 normal children 12-18 years of age were examined by ultrasonography to measure the cartilaginous sulcus angle on the patellar surface of the femur. In knees with patellar dislocation, the cartilaginous sulcus angle measured between 154 and 195 degrees, exceeding the corresponding values of normal knees (134-153 degrees). In patient knees, the cartilaginous sulcus was also consistently wider than the underlying osseous sulcus. This suggests that in pediatric patients with patellar dislocation, the actual patella-stabilizing ability of the femoral sulcus is weaker than the osseous outline in axial radiographs would lead one to suppose. It would appear also that by measuring the cartilaginous sulcus angle of the femur, a clear distinction can be made between normal knee joints and joints displaying patellar instability.

Adolescent↗

PubMed1995

Surgery in acute patellar dislocation--evaluation of the effect of injury mechanism and family occurrence on the outcome of treatment.

A retrospective study was made of 270 patients and 284 knees with acute patellar dislocation treated operatively. The mean follow up time was 4.1 years. Medical history revealed 21.1% of cases with previous dislocations and 15.6% of cases with family occurrence of patellar dislocation. The dislocation resulted from an athletic performance in 41.5% of cases. The sport events most often associated with patellar dislocation were soccer, gymnastics, and ice hockey. All cases were treated with reefing of medial capsule. Release of lateral patellar retinacula was performed in 243 cases. Two cases were treated primarily with the Elmslie-Roux-Trillat procedure. The subjective result of operative treatment was better and the redislocation rate was lower if the injury mechanism was traumatic rather than non-traumatic and if there was no history for family occurrence of patellar dislocation.

Acute Disease↗

PubMed2005

Femoral neuropathy due to patellar dislocation in a theatrical and jazz dancer: a case report.

This case report describes a teenage female, high-level modern dancer who suffered multiple left patellar dislocations. Her history is atypical in that after her fifth dislocation, her recovery was hindered secondary to persistent weakness and atrophy of her quadriceps out of proportion to disuse alone. Electrodiagnostic studies and magnetic resonance imaging showed evidence of a subacute femoral neuropathy correlating chronologically with her most recent patellar dislocation. This case suggests that further diagnostic study may be warranted in patients with persistent quadriceps weakness or atrophy after a patellar dislocation, because this may suggest the presence of a femoral neuropathy. This is important because the strength training goals and precautions differ in disuse atrophy and a neuropathy. We believe this is the first reported case of a femoral neuropathy associated with the mechanism of a patellar dislocation.

Adolescent↗

PubMed2003

Sonographic appearances of medial retinacular complex injury in transient patellar dislocation.

AIM: To describe the sonographic appearances of the medial retinacular (MPFR) complex of the knee in patients with acute and recurrent patellar dislocation. MATERIALS AND METHODS: Thirty patients were scanned within 2-4 weeks of an acute episode of lateral patellar dislocation. Eleven gave a history of recurrent patellar dislocation. Ten patients had examination under anaesthesia with arthroscopy and repair of the injury. The sonographic and operative results were compared. RESULTS: The normal sonographic appearance of the MPFR is described. Of the 10 patients who underwent examination under anaesthesia, four patients had complete avulsion of the MPFR from the patella, two patients had avulsion of the MPFR from the adductor tubercle and four patients had avulsion of the MPFR from both the patella and adductor tubercle. There was complete correlation between the sonographic and operative findings for injuries of the MPFR. Other findings included partial retinacular tears, injury to the medial collateral ligament, haematoma within vastus medialis obliquus (VMO) and bony avulsions from the patella and adductor tubercle CONCLUSION: Sonography gives reliable information regarding the site of the injury and its extent thus helping to decide whether conservative or operative treatment is the most appropriate approach to management of the injury.

Acute Disease↗

PubMed2003

[Study of the patellar apex in objective patellar dislocation].

PURPOSE OF THE STUDY: The purpose of this work was to study the morphology of the patella in search of dysplasia typical of objective patellar dislocation. MATERIAL AND METHODS: One hundred forty patients (190 knees), 80 women and 60 men, who underwent surgery between 1988 and 1999 were included in this study. Mean age was 22.6 years (range 13-47). Patellar morphology was analyzed on the preoperative lateral x-rays (n=190) taken at 30 degrees flexion. The apex of the patella was measured as well as the length of the patellar tendon. The width of the patella was measured on the computed tomography scan (n=158). For 64 knees, magnetic resonance images of the patella were available on which the length and width of the patella, the articular surface, and the patellar tendon were measured. Ninety contralateral knees were symptom free and x-rays were available for 67. RESULTS: According to the Grelsamer classification, 80% of the patellae presented a normal apex. The length of the patellar apex was significantly shorter when the patellar ligament was longer. Using the Wiberg classification, men had more dysplasic patellae (grade C) (p=0.007). There was also a correlation between the Wiberg classification and the Maldague classification. The length of the medial border of the patella and the patellar angle were 2 factors directly related to the Wiberg classification. Mean width of the patella was 39.1 mm (computed tomography measurements). The mean length of the patellar tendon was 53.8 on the magnetic resonance images with a mean articular surface measuring 30.8 mm, a mean patellar length measuring 40.6 mm, and a mean width measuring 38.7 mm. There was no correlation between trochlear dysplasia and patellar morphology. DISCUSSION: There is little data in the literature concerning patellar morphology since Wiberg's work in 1941. The hypothesis of patellar dysplasia rather than trochlear dyplasia, the principal factor involved in objective patellar dislocation, has not been explored extensively. The presence of a hypoplasic medial border, Wiberg grade C, or a short patellar apex suggests that a particular patellar morphotype would be involved in objective patellar dislocation.

Adolescent↗