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PubMed2004

Patellofemoral relationships and cartilage breakdown.

We evaluated the association between patellofemoral relationships and cartilage lesions in patients (age range 15-49) with anterior knee pain without patellar dislocation (n = 24) and in patients with isolated meniscal rupture without a high energy trauma (n = 21). The position of the patella was assessed from knee radiographs, and cartilage lesion was graded and mapped at arthroscopy. In subjects with lateral patellar cartilage lesion the patella tilted laterally (p < 0.01) and was clearly laterally displaced (p < 0.001), compared to those without patellar cartilage lesion. In subjects with central patellar cartilage lesion the patella located high according to the Insall-Salvati index (p < 0.01) and was somewhat laterally displaced (p < 0.05). Compared to subjects without cartilage lesion in the femoral trochlea, the patella was laterally displaced in subjects with lesion in the lateral trochlea (p < 0.001). In conclusion, our results suggest that specific malalignments predispose to patellofemoral cartilage lesion, but prospective studies are needed to confirm the finding.

Adolescent↗
PubMed2000

Radiographic and computed tomographic analysis of the position of the tibial tubercle in recurrent dislocation and subluxation of the patella.

Among the factors that influence the patellofemoral alignment and stability, the position of the tibial tubercle was evaluated using plain radiographs and computed tomography (CT). Radiographs of the Q-angle with the knee in full extension and quadriceps muscle relaxed showed that mean Q-angles in the dislocation or subluxation group and control group were 13.8 degrees and 14.3 degrees, respectively. The major reason for this deceptive measurement was a patella positioned laterally in the dislocation or subluxation group. Better estimation was made with the modified Q-angle measurement by using the most concave point of the intercondylar notch as a reference point instead of the center of the patella. By overshadowing CT images of the levels of the patellofemoral joint and the tibial tubercle, it was possible to evaluate the location of the tibial tubercle in relation to the femoral trochlea. Both the angular measurement (lateral deviation angle [LDA]) and the distance measurement (lateral deviation index [LDI]) showed that the tibial tubercle in the dislocation or subluxation group was rotated externally and shifted laterally (LDA, 36.3+/-7.0 degrees and LDI, 30.1+/-5.6) compared with the control group (LDA, 20.2+/-7.1 degrees and LDI, 15.1+/-5.6). Further study is warranted to elucidate the exact mechanism of recurrent patellar dislocation and subluxation.

Adult↗
PubMed1992

Role of arthroscopic lateral release in the treatment of patellofemoral disorders.

The results of 50 arthroscopic lateral releases are reported. The average follow-up period was 36 months with a range of 18-52 months. Satisfactory results were achieved in 71% of 21 patients with patellar pain alone and in 76% of those (Betz RR, Lonergan R, Patterson R. The percutaneous lateral retinacular release Orthopaedics 1982;5:57-62) with instability. Patients with patellofemoral osteoarthritis or patellar dislocation were excluded from the series. Postoperative hemarthrosis occurred in 10%. Unsatisfactory results could be related to incomplete release, severe chondromalacia, or insufficient rehabilitation. Lateral release is capable of producing high rates of success with a low incidence of complication when used to treat patellar pain with tight retinaculum, patellar instability, and subluxation.

Arthroscopy↗
PubMed1989

A metal-backed, rotating-bearing patellar prosthesis to lower contact stress. An 11-year clinical study.

A congruent-contact, metal-backed, rotating-bearing patellar prosthesis has been used clinically over an 11-year period. The features of this implant include a congruent-contact, rotating bearing attached to a thin metallic anchoring plate fixed to the bone by cruciate fixturing fins. The device was initially used with methylmethacrylate and later used as a cementless, porous-coated, ingrowth fixation implant. The benefits of congruent contact with mobility to adjust its tracking position during flexion and extension help to eliminate axial shear stresses at the bone-prosthesis interface and lower the contact stresses at the bearing-metal interface to improve wear properties. Prostheses were implanted in 515 knees over a period of six months to 11 years. Of these 515 knees, 331 patellar prostheses have been followed for 24 to 132 months (mean, 73 months). Of that group of 331 implants, 141 were cemented and 190 were cementless. Specific complications involving the use of this implant were as follows. One intraoperative vertical midpatellar fracture in a cemented case went on to uneventful healing with an excellent result. Two displaced postoperative transverse midpatellar fractures (0.39%) occurred in two revision total knee arthroplasties that involved major lateral releases. One of those was a cemented revision and required removal of the implant and a partial patellectomy to gain an excellent result. In the other, a noncemented revision, the patient lacks 45 degrees of quadriceps extension and has a poor result following traumatic fracture at three years postsurgery. One patellar dislocation (0.19%) occurred in a 270-pound, osteoarthritic man in whom undersized components were used. No polyethylene wear-through, separation from the metal anchoring plate, or implant breakage was seen in this series. Overall, the performance of this congruent-contact, metal-backed, rotating-bearing patellar prosthesis indicates the prosthesis can provide long-term function and stability with few short-term or long-term complications.

Adult↗
PubMed2000

[Acute and chronic patella dislocations. Therapeutic strategies in Danish orthopedic departments].

BACKGROUND: In review of the literature there is no standard treatment of acute- as well as recurrent dislocation of the patella. Most investigations are retrospective or not randomised. Approximately 1500 patients/year with the diagnosis luxatio patellae are seen in Danish hospitals. METHODS: Using a questionnaire we wished to find out how these patients were treated in Danish orthopaedic departments. RESULTS: We found that there was no consensus on the treatment of patellar dislocation. CONCLUSION: We concluded that there is a need for prospective randomised studies involving a large number of patients, with a long follow up time.

Acute Disease↗
PubMedDate not supplied

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.

Child↗
PubMed1988

Posteriorly stabilised total-condylar knee replacement. Three to eight years' follow-up of 85 knees.

We have reviewed 85 knees in 71 patients after total-condylar posteriorly stabilised (Insall-Burstein) knee replacement with an average follow-up of five years. Excellent or good results were obtained in 90% with an average maximum flexion of 98 degrees. The four poor results (5%) included two with deep infection, one with patellar dislocation and one with loosening. Four other knees (5%) showed signs of probable tibial loosening, but the patients were asymptomatic, the clinical results had not deteriorated with time and lucent lines had not progressed. Varus alignment of the knee and a varus tilt of more than 2 degrees of the tibial component correlated with the incidence of lucent lines around the tibial implant. No patellar stress fractures were seen but impingement symptoms were present in 20%, although they were troublesome in less than half of them. The virtue of the prosthesis lies in its versatility for use in the severely deformed joint.

Adult↗
PubMed1999

[Arthroscopic repair of the medial retinaculum after first time dislocation of the patella].

Between March 1994 and December 1997, an arthroscopic repair of the medial retinaculum after first time dislocation of the patella was performed 38 times in 34 patients. The operative technique is being described as well as the results after an average follow-up of 25 months in 31 cases. In the group with radiologically determined predisposing factors (n = 20) as many osteochondral flakes were found as in the group without these factors, but there were significantly less chondral lesions on the lateral femoral condyle and the medial patellar facet. There were no complications during hospitalization, although in 3 (10%) cases a redislocation occurred during follow-up. According to the subjective Turba Score, 84% of the patients showed a good or very good, and 16% a fair result, including cases with redislocation. The arthroscopic repair of the medial retinaculum after first time patellar dislocation is a minimal invasive method with very low peri- and postoperative morbidity. The redislocation rate can be reduced to at least 50% compared to the published data on conservative treatment.

Adolescent↗
PubMed1998

The patellar tilt angle: correlation of MRI evaluation with anterior knee pain.

The purpose of this study was to analyze the degree of patella tilt and its correlation with the symptoms of anterior knee pain. We used magnetic resonance imaging (MRI) to measure the angle of patella tilt. The patients (n = 128) were classified into two groups. Group 1 (n = 78) included patients who had never had symptoms of anterior knee pain but had MRI for evaluation of the menisci and the ligaments. Group 2 (n = 50) included patients who had MRI for evaluation of anterior knee pain syndrome. Patients who had gross deformities like patellar dislocation, tricompartmental osteoarthritis, or inflammatory arthritis were excluded. The average patella tilt angle was 6.3 (SD = 3.9) and 12.8 (SD = 8.4) degrees, respectively, for the two groups of patients. Twenty-three patients in group 2 underwent arthroscopy because of failure of conservative treatment, and the average patella tilt angle in this subgroup was 16.4 degrees. Our study suggests that patella tilt angle is correlated with the symptoms of anterior knee pain, and indicated that the cause of pain came from the tight lateral retinaculum. In addition, MRI was found to be an accurate and reproducible method of measurement of the patellar tilt angle.

Adolescent↗
PubMed1997

Operative versus closed treatment of primary dislocation of the patella. Similar 2-year results in 125 randomized patients.

To assess whether initial surgery is beneficial for patients with primary dislocation of the patella, we carried out a prospective randomized study. Knee stability was examined under anesthesia, and associated injuries were excluded by diagnostic arthroscopy. 55 patients then had closed treatment and 70 patients were operated on with individually adjusted proximal realignment procedures. Surgery gave no benefit based on 2 years of follow-up. The subjective result was better in the non-operative group in respect of mean Houghston VAS knee score (closed 90, operative 87), but similar in terms of the patient's own overall opinion and mean Lysholm II knee score. Recurrent instability episodes (redislocation or recurrent subluxation) occurred in 20 nonoperated and in 18 operated patients. Of these, 15 and 12, respectively, then suffered redislocations. Function was better after closed treatment. Serious complications occurred after surgery in 4 patients. In conclusion, the recurrence of patellar dislocation may be more frequent than reported, whatever the form of treatment. Routine operative management cannot be recommended for primary dislocation of the patella.

Adolescent↗
PubMed1975

Cryptorchism and related defects in dogs: epidemiologic comparisons with man.

In a study of 1266 dogs with cryptorchism from a large clinic/hospital series 8 breeds were found to be at excess risk of the defect and 3 breeds at significantly low risk. Review of the medical histories revealed that hip dysplasia, patellar dislocation, defects of the penis and prepuce, and umbilical hernia were excessively associated with cryptorchism. Testicular tumors were diagnosed 10.9 times more commonly among cryptorchid dogs. The epidemiologic features of canine cryptorchism were compared with those in man. Cryptorchid dogs could be used as models for etiologic research.

Animals↗
PubMed1992

Calcitonin gene-related peptide, substance P and GAP-43/B-50 immunoreactivity in the normal and arthrotic knee joint of the mouse.

The aim of this study was to describe the normal distribution of calcitonin gene-related peptide (CGRP) and substance P (SP) containing fibres in the knee joint of the mouse and to obtain insight into the changes in innervation associated with degenerative processes in the joint. Arthrosis was induced by a single subpatellar intra-articular injection of bacterial collagenase. After decalcification in EDTA solutions, the CGRP and SP fibres were visualized by peroxidase-antiperoxidase pre-embedding immunocytochemistry for light microscopy. Control experiments on the mouse brain as a reference for the effect of EDTA on the immunostaining showed that the decalcification procedure with EDTA had not impaired the immunostaining. A rich innervation of thin varicose CGRP and SP immunoreactive fibres was found in most peri- and intra-articular tissue components. The periosteum, synovial tissues, the joint capsule and the intra-articular fat tissues were richly innervated. Less intense innervations were also found in the subchondral bone plates of the tibio-femoral joint and of the patella. Fibres were also found in the soft tissues between the patellar tendon and the femoral groove. No differences could be found between the location of CGRP and SP fibres with respect to the localization in the joint, but generally more CGRP fibres were found. The collagenase-induced osteoarthrosis was characterized by sclerosis of the subchondral bone, patellar dislocation, osteophyte formation, synovial proliferation and by severe cartilage abrasion, particularly on the medial side of the femoro-tibial joint. The overall distribution of CGRP and SP fibres was the same as in the control joints. However, major differences were found in all studied joints at specific locations around the cruciate ligaments, in the synovium around the patella, in the soft tissues lateral of the patella and in plica tissue between the patella and femoral groove. The CGRP and SP innervation was no longer detectable by immunolabelling with the antibodies. With a polyclonal antibody to the growth associated protein GAP-43/B-50, signs of degenerated axonal profiles were observed in these locations. At other peripheral locations, such as the muscles, the GAP-43/B-50 distribution was normal. In conclusion, the present study provides detailed information on the localization of CGRP and SP fibres, which may be involved in pain perception. Knowledge of the changes that occur during arthrosis may give more insight into the clinical symptoms.

Animals↗
PubMed1988

The significance of hemarthrosis of the knee in children.

Diagnostic arthroscopy was performed in 40 consecutive patients under 16 years of age with hemarthrosis of the knee. The age of the patients ranged from 10 to 15 years, median 13.7 years. Eighteen patients had ruptures of the anterior cruciate ligament; seven ruptures were partial. Only two cases of fractures of the tibial spine were encountered. Seven patients had midsubstance tears of the anterior cruciate ligament. Eleven patients had patellar dislocations. Six patients had minimal capsular disruptions as the cause of hemarthrosis. Three patients had osteochondritis dissecans of the knee and two patients had isolated ruptures of the medial collateral ligament. Twenty-eight of the patients underwent some form of operative repair. The clinical diagnosis was confirmed at arthroscopy in 17 of the 40 cases. The appearance of hemarthrosis of the knee usually signifies a serious knee injury and should be treated with the same importance as in adults, and as a rule arthroscopy should be carried out.

Arthroscopy↗
PubMed1993

Arthroscopy in patients with knee endoprostheses.

Remarkable advances have been made in knee replacement. Nevertheless, patients and surgeons still face unsolved problems following implantation of an artificial knee joint. In some cases arthroscopy may serve as a diagnostic or surgical tool. Our experience has shown that arthroscopy is helpful in diagnosing polyethylene wear, fractures of prosthetic components and loosening of the endoprosthesis. Moreover, surgical procedures can be synchronously performed, e.g. lateral release for complete or partial patellar dislocation, parapatellar denervation for retropatellar pain and resection of meniscal remnants or a synovial plica in case of interposed tissue. In contrast to knee infections, early prosthetic infections should be treated with an open procedure.

Aged↗
PubMed2001

Distribution of patellofemoral joint pressures after femoral trochlear osteotomy.

Anterior osteotomy of the lateral femoral condyle was designed for the treatment of recurrent patellar dislocations. This study examined whether anterior femoral trochlear osteotomy significantly elevates contact pressures in the patellofemoral joint. Static intrajoint loads and contact area determination were recorded using prescale Fuji pressure-sensitive film under static loading. Peak pressures, average pressures and contact areas of the patellofemoral joint were calculated on intact specimens and after anterior osteotomy of the lateral condyle. Our results indicate that a 6-mm or 10-mm anterior osteotomy of the lateral condyle significantly elevates patellofemoral contact pressures.

Adult↗
PubMed2004

MRI of Hoffa's fat pad.

The infrapatellar fat pad of Hoffa is commonly injured but rarely discussed in the radiological literature. Abnormalities within it most commonly are the consequences of trauma and degeneration, but inflammatory and neoplastic diseases of the synovium can be confined to the fat pad. The commonest traumatic lesions follow arthroscopy, but intrinsic signal abnormalities can also be due to posterior and superior impingements syndromes and following patellar dislocation. Infrapatellar plica syndrome may also be traumatic in aetiology. The precise aetiology of ganglion cysts is not understood; the principal differential diagnosis is a meniscal or cruciate cyst. Hoffa's fat pad contains residual synovial tissue, meaning that primary neoplastic conditions of synovium may originate and be confined to the fat pad. Inflammatory changes along the posterior border of the pad may also be used to help differentiate effusion from acute synovitis on unenhanced MR examinations.

Adipose Tissue↗
PubMed1999

Factors affecting the rectus femoris-patellar tendon Q-angle, measured using a computed tomographic scan.

We devised a method to measure the Q-angle (the angle between the rectus femoris and the patellar ligament), using computed tomography (CT), in 1993. In this study, I investigated the lateral shift at each point forming the angle as factors affecting the Q-angle. The study group consisted of 83 patients with recurrent patellar dislocation (83 lower limbs) and a control group of 55 healthy people (55 lower limbs). A lateral shift was found in the anterosuperior iliac spine (ASIS) in the dislocation group compared with the control group (P < 0.01). A lateral shift was also found in the anteroinferior iliac spine (AIIS) in the dislocation group compared with the control group (P < 0.05). A medial shift was found in the bottom of the groove of the femoral condyle in the dislocation group compared with the control group (P < 0.001). A lateral shift was also seen in the tibial tubercle of the dislocation group in comparison with the control group (P < 0.0001). Lateral shift of the tibial tubercle may be the main factor influencing the Q-angle, as measured by CT.

Adolescent↗
PubMed2003

Lateral femoral condylar shearing fractures.

Lateral femoral condylar shearing fractures occur as the aftermath of acute patellar dislocation. The fracture fragment may be larger than originally appreciated on plain films. Diagnosis depends on identifying the fracture fragment somewhere within the knee joint, and the "donor site" on the lateral femoral condyle. Therefore, MRI or arthroscopy should be performed to identify the true size of the fracture fragment. The larger of these fragments may require surgical intervention with fixing of the fracture fragment onto the lateral condyle with screws. We present the radiographic and clinical findings in seven patients.

Journal Article↗