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PubMed1989

Chondromalacia induced by patellar subluxation in the rabbit.

A unilateral patellar malalignment was induced in 20 young and 20 mature rabbits by lateral displacement of the tibial tuberosity, the other knee serving as osteotomized in situ control. At 6 weeks, all the knees appeared macroscopically normal, but histologically definite cartilage degeneration was found on the experimental side. At 3 months, macroscopic changes occurred in 5 of 10 mature rabbits, and histologic cartilage degeneration was found in all the experimental knees, most pronounced in mature animals, and particularly in joint facets submitted to high pressure. This experimental model produces changes resembling chondromalacia patellae and early arthrotic changes suggesting the importance of malalignment in the development of patellofemoral cartilage degeneration.

Animals↗

PubMedDate not supplied

Fluoroscopic technique for double-contrast knee arthrography.

The fluoroscopic double-contrast technique of arthrography of the knee is useful in documenting the extent of suspected injury to the knee. It is of particular value in demonstrating small and large lesions involving the menisci, cruciate ligaments, patellar cartilages, as well as the articular cartilages of the femoral condyles and tibial plateaus. This examination is instrumental in the diagnosis of the patient with an atypical history of injury and unusual physical findings. A simple restraint device allows the fluoroscopist complete control over the stress applied to the knee while positioning the patient for filming. Fluoroscopic spot radiographs of excellent contrast and sharp detail can be obtained of each of the various structures, applying the stress needed. When the radiologic technologist takes a little time to become more knowledgeable about the anatomy of the knee jount, and the rationale for the various views, the knee arthrographic examination is easily understood.

Cartilage, Articular↗

PubMed1987

Arthroscopic determination of patellofemoral malalignment.

Patellofemoral alignment was determinant by arthroscopy according to the degree of knee flexion at which the lateral facet, the patellar ridge, and the medial facet of the patella gained contact with the femur. The intraarticular pressure was 75 mm Hg. In 17 patients with a normal patellofemoral joint, the lateral facet aligned at a mean knee flexion of 20 degrees, the patellar ridge at 35 degrees, and the medial facet at 50 degrees. Twelve patients with patellar subluxation showed no difference in the alignment of the lateral facet, but differed significantly with regard to alignment of both the ridge and the medial facet with contact at a mean flexion of 55 degrees and 85 degrees, respectively. The median measurements in 20 patients with idiopathic anterior knee pain did not deviate significantly from the normal material. However, the dispersion was increased significantly, with eight patients having increased measurements consistent with malalignment and three having decreased measurements below the lower limit of normal alignment. Patients with idiopathic anterior knee pain apparently can be reclassified according to the arthroscopically determined alignment, which may prove important in the treatment of these patients.

Adolescent↗

PubMed1978

The abnormal lateral patellofemoral angle: a diagnostic roentgenographic sign of recurrent patellar subluxation.

On roentgenograms made with the patient supine, the knees flexed 20 to 30 degrees, the x-ray tube between the ankles, and the cassette held proximal to the knees and perpendicular to the x-ray beam, it was found that a line between the femoral condyles and a line between the margins of the lateral facet of the patella formed the lateral patellofemoral angle, an angle that was of diagnostic value in patients with subluxation of the patella. In 100 clinically normal patients, these lines were parallel in three and formed an angle open laterally in ninety-seven. In thirty patients with subluxation of the patella, the lines were parallel in twenty-four and formed an angle open medially in six. In 100 patients with chondromalacia of the patella, however, the roentgenographic study was of no diagnostic value since the lines were parallel in ten and formed an angle open laterally in ninety.

Female↗

PubMed1982

Anterolateral rotary instability of the knee joint. Results after stabilization by extraarticular transposition of the lateral part of the patellar ligament. A preliminary report.

A method using the lateral third of the patellar ligament and the adjacent part of the patella as an extraarticular transplant to the lateral femoral condyle in the stabilization of anterolateral rotary instability of the knee is described and discussed. The operation was performed in six patients. The stabilizing effect of the procedure could be evaluated in only five of them due to the development of septic arthritis in one patient. Four of these five patients had ruptured the anterior cruciate ligament, while the fifth patient had a congenital anterolateral instability. In this patient the procedure was combined with an Ellison operation. In all five patients the operation eliminated the instability and resulted in good function. The procedure is recommended for further testing in the treatment of anterolateral rotary instability of the knee as an alterative method to procedures applying the iliotibial band.

Adolescent↗

PubMedDate not supplied

Medial patellar luxation in 16 large dogs. A retrospective study.

Unilateral medial patellar luxation was diagnosed in 10, and bilateral medial patellar luxation in six, large and giant-breed dogs (22 stifles). Lameness occurred in five dogs after trauma or surgery, and 11 dogs had no known predisposing history. The mean age at presentation was 25 months, and the mean time from initial onset of clinical signs to diagnosis was 13 weeks. All traumatic or iatrogenic luxations (five dogs) were unilateral. Luxations presumed to be congenital were unilateral in five dogs and bilateral in six. The grades of medial patellar luxation were I (1 stifle), II (11 stifles), III (9 stifles), and IV (1 stifle). Preoperative function was good (1 dog), fair (9 dogs), and poor (6 dogs). Surgical correction was performed in dogs with grades II, III, and IV luxations (21 stifles). Complications included one wound dehiscence and trochlear wedge migration, one pin loosening, and one persistent lameness caused by lymphoplasmacytic synovitis. Long-term follow-up was available in 13 dogs (18 stifles). Function was judged by owners to be excellent in seven dogs, good in five dogs, and poor in one dog. Surgical treatment of grades II and III luxations yielded good (8 stifles) and excellent (9 stifles) results, while one grade IV luxation had a poor long-term outcome.

Animals↗

PubMedDate not supplied

Management of patellar subluxation. A modification of Hauser's technique.

Patellar subluxation is one of the most common causes of internal derangement of the knee in young individuals. Most surgical techniques mandate entrance into the knee joint and require prolonged postoperative immobilization. The result may be excessive postoperative synovitis and occasionally, hemarthrosis. Prolonged postoperative immobilization results in joint stiffness. The authors propose a modification of Hauser's technique which allows tailored correction of the abnormal vector forces applied to the patella, simple adjustment of the tension in the extensor mechanism, creates patellar stability, and permits rapid return of knee motion. A new tibial corticocancellous window is created in a manner similar to Hauser's technique. The cancellous defect is deepened by curettage and the transferred tibial tubercle is then inverted, inserted through the window, and tamped into the graft bed thereby gradually increasing tension in the tendon. The cancellous and cortical bone from the window is then tamped in behind the patella tendon, buttressing the tendon, and permitting the knee a full unguarded range of motion on the operating table. In 23 operations in 22 patients, with a follow-up of 35.4 months and a mean patient age of 18.7 years, all patellae were stable. All but one patient achieved full range of motion. Younger patients with minimal or absent preoperative patellofemoral chondromalacia had uniformly good results.

Follow-Up Studies↗

PubMedDate not supplied

Surgical correction of medial subluxation of the patella.

We evaluated the results of a surgical procedure to correct medial subluxation of the patella in 63 patients (65 knees), most of whom had undergone a lateral retinacular release. We performed a direct repair or a reconstruction of the lateral patellotibial ligament using locally available tissue such as strips of iliotibial band or patellar tendon. Followup averaged 53.7 months (range, 24 to 99). Outcome was based on the examiner's inability to clinically reproduce the patient's painful medial subluxation and on the patient's general impression of his or her improved functional status. Forty-four patients (68%) reported improvement in their functional levels and 49 (75%) reported that they were subjectively improved by the procedure. Overall, 50 patients (80%) had a rating of good or excellent. Six knees required a second surgical reconstruction because of failure to improve or because of a reinjury. Analysis of overall clinical outcome revealed no significant relationships based on the patient's age at the time of the initial procedure, sex, or length of followup (P > 0.10). Reconstitution of the lateral patellotibial ligament effectively corrected medial subluxation of the patella and long-term results of this salvage procedure were satisfactory.

Adolescent↗

PubMed1996

[Differential indications for so-called "lateral release" in treatment of chondropathia patellae].

The success rate of the operation of lateral release for pain caused by the patella is reported as being between 14% and 99%. The choice between arthroscopic or open procedures does not seem to affect the results. The wide ranges of results probably reflects differences in patients selection or the method and investigations of follow up. The early term outcome usually show better results than long term follow up. This study evaluates the indications for the operation of lateral releases and discusses the result of 36 out of a total of 42 patients who were follow up for 3 years later surgery. We found that an insufficiency of dysplasia of the vastus medialis, the laxity of the capsule and soft ligaments, and a strong lateral retinaculum were important factors in the indication for this procedure. The quadriceps angle was also of prime importance, but the minor forms of patellar dysplasia played only a minor role. In the so-called hyperpression syndrome, where the patella has a strong tendency to move laterally, the simple lateral release is the single most successful operation. The indication for procedures additionally to the lateral release is examined. We found that in a case with an insufficiently guided patella, a weak capsule and ligaments, an additional capsule roughing should be performed. The presence of early degenerative changes in the joint predisposes to poor results in operations such as abrasion and pride drilling. The results in our study were assessed using the Lysholm score. Our results show that the most successful technique was the combination of an arthroscopy and an extraarticular open operation controlled by arthroscopic means. This technique was not associated with major complications such as haemarthrosis and consecutive prolonged postoperative rehabilitation. Overall we achieved a rate of 83% of good or satisfactory results at more than 3 years using the indications and techniques described above.

Adult↗

PubMed2003

Electromyography of the quadriceps in patellofemoral pain with patellar subluxation.

This study compared muscle activity and timing of gait phases during functional activities in 13 subjects with patellofemoral pain associated with lateral subluxation and in 11 subjects with healthy knees. Fine wire electromyography recorded activity in the vastus lateralis and vastus medialis oblique during walking and ascending and descending stairs. Subjects were filmed to divide the activities into phases and determine timing. The vastus medialis oblique and vastus lateralis had similar patterns during all activities. Subjects with patellofemoral pain had significantly increased activity in the vastus medialis oblique and vastus lateralis compared with the healthy subjects during the most demanding phases of the gait cycle, suggesting a generalized quadriceps weakness in the patients with patellofemoral pain. Timing differences were seen in walking and stair ascending with the subjects with patellofemoral pain spending significantly more time in stance compared with the healthy subjects. This may be an attempt to reduce the load on weak quadriceps. These data reflect a generalized quadriceps muscle weakness, rather than the prevailing theory of quadriceps muscle imbalance as an etiology of patellofemoral pain. Therefore, we support the practice of strengthening the entire quadriceps muscle group, rather than attempting to specifically target the vastus medialis oblique.

Adolescent↗

PubMed2000

Assessment of patellar maltracking using combined static and dynamic MRI.

Between January 1995 and Jul 1997, 474 patients with anterior knee pain resistant to conservative treatment were referred for MR of the knee. The MR examination consisted of routine sequences with an additional patellofemoral dynamic examination using a technique that has been developed at this institution. The dynamic study examines both knees simultaneously, with the patient supine and the quadriceps loaded. No gating or restraint apparatus is needed. Patellar subluxation or tilt was present in 188(40%) of cases, bilateral in 104 and unilateral in 84 cases (right 39, left 45). It was classified as mild in 51%, moderate in 39% and severe in 10%. Subluxation was more prevalent in females than males (42% vs. 37%) and this was most obvious in the severe group where 68% were female. In 90 knees selected at random, four measurements of patellofemoral morphology were obtained using reconstructed images from a volume gradient echo sequence. These measurements were correlated with the degree of subluxation or tilt. A tibial tubercle distance greater than 20 mm, a femoral sulcus angle greater than 150 degrees, sulcus depth less than 4 mm were specific for subluxation but no measurement proved to be sufficiently sensitive to preclude a tracking study. MRI can be used to define more precisely the anatomy of the extensor mechanism and its relationship to the femur and tibia, in both a static and dynamic setting. In this way, patients with anterior knee pain can be classified more accurately and the outcomes of treatment more reliably assessed.

Adult↗

PubMed1986

Anterior tibial tubercle elevation in the young adult.

A modification of Maquet's procedure, longitudinal proximal tibial osteotomy, was performed on 36 adults under the age of 40. The tibial tubercle was elevated between 2.0 and 2.5 cm. Fourteen were operated on for significant osteochondral injury to the underside of the patella, including patellar fracture; 16 were operated on because of osteoarthrotic change in the patellofemoral joint secondary to recurrent subluxation. Six were operated on because of pain persisting after previous patellectomy. Follow-up ranged between 2 and 5 years, was at least 2 years, and averaged 3.53 years. A good result was determined to be one in which the patient had no pain requiring medication or activity limitation; a poor result was designated when the patient had pain requiring medication or activity limitation. The success rate among the trauma or fracture group was 94 per cent, among the subluxation group 88 per cent, and among the postpatellectomy group 66 per cent. Failures included unrecognized osteoarthrosis of the tibiofemoral joint, psychiatric problems, a reflex sympathetic dystrophy, a compensation neurosis, a failure to correct excessive knee valgus with recurrent subluxation, and a fall displacing the operation. Serious complications, osteomyelitis and a displaced graft resulting from a postoperative fall, occurred at a rate of 5 per cent; minor complications, tenuous skin healing and tibial tubercle shingle fractures, occurred at a rate of 19 per cent. This operation is indicated only for patients with osteoarthrosis of the patellofemoral joint and is contraindicated in the presence of tibiofemoral osteoarthrosis. High success rates are attributed to careful attention to indications and contraindications and to the design and details of performing the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989

Patellar subluxation. A recent history.

For 15 years (1955 to 1970), I was plowing "new ground" pretty much by myself. When you plow behind an old mule and hit a stump hole full of cottonmouth moccasins, you have to get on the move in a hurry and figure out some solution to the predicament or you won't get your corn planted. So, I was not treating the overweight, knock-kneed, loose-jointed, teenaged girl, but the young boy or girl who thought that he or she was an athlete and had dreams of being a star. If rehabilitation did not work, then I thought a lateral release, an Elmslie, and nothing short of a full reconstruction would solve the problem. One had to develop as much vastus medialis obliquus power as this dysplastic muscle could generate, had to transfer the strong vastus lateralis to a more central pull, and, with the distal reconstruction, correct any patella alta and Q-angle abnormality. One had to give the knee every possible advantage in order to serve an athlete. As Hippocrates so wisely noted, one needed to study the athlete to know, with appropriate modifications, what is best for every patient, young or old. In the late 1960s and early 1970s, many fine young orthopedists were stimulated by the information of the AAOS postgraduate courses in sports medicine. They, after having gained further through their own experiences, have become the major contributors to our increasing knowledge of the patellofemoral joint, especially in athletes, and many of these fine "young" (now a little older) orthopedists are now the contributors to this issue. They are giving you their experiences, knowledge, and lessons. A close and repeated study of their information must be combined with compassion for your patient. Then, only experience will develop the desired fine tuning.

Humans↗

PubMedDate not supplied

Clinical results of surgical correction of medial luxation of the patella in dogs.

Thirty-four dogs that had surgical correction of medial patellar luxation (MPL) in 52 stifle joints were examined after a minimum follow-up period of 1 year (median, 3.6 years). The dogs were divided into the following three groups depending on their age at the time of surgery: group 1, 3 to 6 months; group 2, 8 to 20 months; and group 3, 2.2 to 12 years. Two of the dogs in group 3 had ruptured their cranial cruciate ligament in addition to having MPL. The results were based on a clinical assessment of the animal's gait, and physical and radiographic examination of the stifle joints. Six of seven stifle joints evaluated in group 1 had radiographic evidence of moderate to severe degenerative joint disease of the patellofemoral joint, and in two of the joints recurrence of MPL was observed. Failure to maintain reduction of the patellofemoral joint was also observed in 11 of 22 (50%) and 12 of 23 (52%) of the stifle joints in groups 2 and 3, respectively. In the latter groups, mild degenerative joint disease was evident radiographically in stifle joint that had not maintained reduction. Four of the 34 dogs were consistently (n = 2) or intermittently (n = 2) lame; the two dogs that were consistently lame had cranial instability of the stifle consistent with rupture of the cranial cruciate ligament. In the latter two dogs, the cranial cruciate ligament had been intact at the time of surgery for correction of MPL.

Age Factors↗