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PubMed2003

Acute lateral dislocation of the patella: correlation of ultrasound scanning with operative findings.

Acute lateral dislocation of the patella has been associated with disruption of the medial restraints of the patella. Following non-operative management there is a re-dislocation rate of up to 44%. The purpose of this study was to test whether sonography is a reliable method of assessing the medial retinaculum after acute dislocation of the patella. Ten patients following acute patellar dislocation had an ultrasound scan (USS) performed by an experienced musculoskeletal radiologist. Each patient subsequently had an examination under anaesthetic, arthroscopy, and repair of the ruptured structures. The ultrasound reports were compared to the surgical findings to determine the accuracy of this investigation. USS located deficiencies in the ligamentous attachments to the medial border of the patella and the presence of avulsed bony fragments, all of which were confirmed at operation. The sonographic diagnosis of haematoma or torn fibres in the vastus medialis obliquus (VMO) corresponded with our operative findings. The most significant findings were the correlation of free fluid around the medial collateral ligament (MCL) with avulsion of the femoral attachment of the medial patellofemoral ligament (MPFL) and the presence of avulsed fragments of bone from the medial border of the patella.

Adolescent↗
PubMed1988

Recurrent dislocations and subluxations of the patella.

Seventy-four patients with patellar dislocations and subluxations were treated with a procedure described by Trillat. The Trillat method consists of stepwise correction of predisposing anatomic abnormalities including lateral retinacular release, patellar tubercle transfer, and advancement of the vastus medialis, if necessary. The follow-up period in 42 knees was from two to nine years with an average of 4.2 years. The results were excellent in six knees, good in 28 knees, fair in five knees, and poor in three knees. Thorough intraarticular examination is essential. If significant patellofemoral arthritis is present, a Maquet procedure should be performed.

Adolescent↗
PubMed2005

Trochleaplasty for patellar instability due to trochlear dysplasia: A minimum 2-year clinical and radiological follow-up of 19 knees.

BACKGROUND: Recurrent patellar dislocation may be associated with trochlear dysplasia. Trochleaplasty is a surgical procedure which strives to deepen the trochlear groove. We evaluated the clinical and radiological effect of trochleaplasty after a minimum follow-up of 2 years. PATIENTS AND METHODS: We examined 19 knees in 16 patients at a mean of 3 years after trochleaplasty. Postoperatively, a subjective questionnaire, a Kujala score, and tests for potential patellar redislocation and apprehension were evaluated. On radiographs we evaluated the preoperative and postoperative crossing sign, trochlear depth, trochlear bump, and patellar height. On CT scans, the pre- and postoperative tibial tuberosity to trochlear groove distance (TTTG) and the patellar inclination angle were measured. RESULTS: 16 of 19 knees improved subjectively. The Kujala score increased from 56 to 80 points at the latest follow-up. None of the patients sustained a redislocation. 5 patients had medial parapatellar tenderness, including 4 with persistent apprehension. Radiological signs of trochlear dysplasia were corrected. INTERPRETATION: Patellofemoral instability with underlying trochlear dysplasia can be treated successfully by trochleaplasty.

Adolescent↗
PubMed2005

Arthroscopic patellar "bankart" repair after acute dislocation.

We present a case of acute patellar dislocation in a skeletally immature patient treated with arthroscopic medial patellofemoral ligamentous complex repair using suture anchors with a horizontal mattress suture technique. Patellar dislocation is a common problem in the skeletally immature. Treatment is controversial for first-time dislocators because of the high rate of recurrent instability and functional disability in these patients. Surgical repair of the medial restraints may decrease recurrent instability, although anterior knee pain and crepitus is a common finding after open surgical techniques. Arthroscopic medial retinacular imbrication has been described for patients with persistent instability with good short-term results. Acute dislocations may cause avulsion of the medial patellofemoral ligamentous complex from the patella; this is amenable to direct primary repair to prevent recurrent instability and avoid the morbidity of open surgery. This technique recreates normal anatomy and function with minimally invasive surgery.

Adolescent↗
PubMed2006

[Preliminary study on treating patellar instability guided by arthroscopy].

OBJECTIVE: To explore the operation method in treating patellar instability guided by arthroscopy and to evaluate its therapeutic effects. METHODS: Thirty-two patients (34 knees) with patellar instability including 2 patellar tilt (2 knees), 26 (27 knees) patellar subluxation, and 4 (5 knees) patellar dislocation, diagnosed by clinical and arthroscopical standard, were treated with anterior transfer of the gracilis or medial transfer of the tibial tuberosity based on the lateral retinacular release and medial tightening. RESULTS: Twenty-eight patients were followed up for 5-87 (mean 36.6) months. The excellence rates was 92.8%. CONCLUSION: The patellofemoral alignment can be seen directly and dynamically under the arthroscopy. The combinational treatment including anterior transfer of the gracilis in repairing patellar instability can avoid the recurrence effectively and get satisfactory results.

Adolescent↗
PubMed2003

Acute traumatic extension deficit of the knee.

The purpose of this study was to evaluate the events leading to acute traumatic extension deficit of the knee and the arthroscopic findings in these patients. A total of 78 consecutive patients treated in the Turku university hospital during the years 1994-1996 were included. The mean annual incidence of acute traumatic extension deficits of the knee in our study was 1.1 per 10 000 inhabitants. The single most common (33%) event causing the extension deficit was non-sports related twisting of the knee. Various sports related activities accounted for 42% of the extension deficits, and soccer was the most common sport in this group. In conclusion, acute traumatic extension deficit of the knee is usually a sign of serious intra-articular damage, and the most likely finding (in 82% of the patients in our study) is either a meniscal rupture, an anterior cruciate ligament (ACL) rupture, a patellar dislocation, or a combination of these. The lesions in these knees require prompt evaluation by an orthopaedic surgeon mainly because of the high number of bucket-handle and menisco-capsular insertion ruptures of the menisci, which are possibly suitable for repair.

Acute Disease↗
PubMed2003

Acute and recurrent patellar instability in the young athlete.

Many reports of patellofemoral instability treatment suffer the same flaws of inappropriate patient selection, poor injury definition, insufficient activity assessment, and, especially in skeletally immature patients, limited followup found in other orthopedic literature. A significant number of dogmatic statements concerning risk factors and treatment interventions continue to be recycled through the literature without adequate clinical or laboratory substantiation, even in the face of contradictory data. Traditionally, patellar instability has been treated with variable periods of immobilization, sporadic rehabilitation, and an expected full return to sports activity. The reality is that many young athletes have long-term retropatella pain and sport-limiting extensor mechanism impairment following patellar dislocations. Most athletes benefit from an initial nonoperative program that is aggressive, multidimensional, and responsive to early treatment outcomes. Concurrent osteochondral injuries are common and a major contributor to adverse outcomes. Diagnostically, MRI is improving in its ability to detail osteochondral injury and it plays an important role in determining the location and extent of MPFL injury. The primary stabilizing role of the MPFL in the normal knee and its injury as an essential lesion of patella instability has been appreciated only recently. There is growing interest in exchanging the myriad of nonanatomic extensor mechanism reconstructions for more anatomic procedures based on restitution of the MPFL.

Acute Disease↗
PubMed1992

Management of recurrent dislocation of the patella following total knee arthroplasty.

Fifteen knees with patellar dislocation after total knee arthroplasty had realignment of the extensor mechanism using a modification of the Trillat procedure. The onset of dislocation occurred on average 4.7 months from the time of surgery. After total knee arthroplasty the patients had an average range of motion of 109 degrees. All patients had medialization of the tibial tubercle and lateral release. No patient had a recurrent dislocation after a minimum 2-year follow-up period. The average knee score was 82 and the average flexion arc was 112 degrees. All but one of the osteotomies healed uneventfully.

Aged↗
PubMed1984

An unusual case of intra-articular dislocation of the patella.

An unusual case of intra-articular patellar dislocation is described in which the patella rotated simultaneously in both the horizontal and vertical axes. The dislocation was sustained without apparent trauma. Reduction could not be accomplished in the emergency department. Closed reduction was accomplished successfully under general anesthesia in the operating room.

Child↗
PubMed2005

Histological evaluation of medial patellofemoral ligament reconstructed using the Leeds-Keio ligament prosthesis.

In a total of 15 knees from 15 patients undergoing medial patellofemoral ligament reconstruction using an artificial substitute and a medial retinaculum slip coverage for recurrent patellar dislocation, the reconstructed ligaments were histologically evaluated using hematoxilin-eosin and elastic van Gieson stains. The artificial substitute was a mesh-type Leeds-Keio ligament. The mean age of the patients at the time of surgery was 20 years (range; 13-38 years). The mean interval from initial reconstruction to gathering was 53 months (range; 11-109 months). In the tissue over the artificial ligament, longitudinally aligned collagen fiber bundles with spindle-shaped nuclei were formed in all specimens except one specimen of 11 months postsurgery, but it seemed to be mature ligament only in specimens more than 60 months postsurgery. The tissue inside the artificial ligament was immature as a whole in all specimens, although 13 out of the 15 specimens had regularly aligned collagen fiber bundles slightly or in some portions.

Adolescent↗
PubMed2005

Cadaveric study on static medial patellar stabilizers: the dynamizing role of the vastus medialis obliquus on medial patellofemoral ligament.

Aim of this cadaveric biomechanical study was to describe the detailed anatomy of the static medial patellar stabilizers and further determine the role of each of them in preventing lateral patellar dislocation. Eight cadaver knees, after removing the skin and subcutaneous tissues, were used in the study. The medial patellofemoral ligament (MPFL), the medial retinaculum (MR) the medial patellomeniscal ligament (MPML), and the medial patellotibial ligament (MPTL) were dissected. Their origins, insertions, orientations and sizes were recorded. To the medial stabilizers, a tension of 10 pounds was applied, using a tensiometer held in a semicircular device while the knees were kept in 30 degrees of flexion. Then, the previously described ligaments were dissected and the resultant displacement recorded. The most anatomically distinct structure is the MPFL, whose length varies from 45-50 mm, and its width from 10-20 mm at its origin (medial femoral epicondyle) to 20-30 mm at its insertion to the patella. The "meshing" of the MPFL fibers to the fibers of the vastus medialis obliquus (VMO) close to its patellar insertion was the most interesting and very important finding. The contribution of MPFL to medial stability was more than 50%. Of the remaining ligaments, MPML contributes 24% and the MPTL and MR contribute only 13% respectively. The MPFL is the strongest medial static patellar stabilizer. Its contribution to patellar stability against lateral dislocation is far more than 50%, since its meshing with the VMO, shortens its fibers which thus pulls the patella to the medial part of the femoral groove and keeps it in the trochlea during the initial 20 degrees -30 degrees of flexion.

Biomechanical Phenomena↗
PubMed1990

The effect of femoral component position on patellar tracking after total knee arthroplasty.

In a laboratory study, seven fresh anatomic knee specimens were evaluated to define the three-dimensional motions of the patella before and after total knee arthroplasty (TKA) with the AMK knee. The patella was displaced medially by an average of 4 mm and tilted medially by an average of 4 degrees after standard TKA. Medial translation or internal rotation of the femoral component further displaced and tilted the patella medially, but lateral translation or external rotation of the femoral component produced less predictable changes in patellar tracking. The patterns of patellar tracking after external rotation of the femoral component came closer to reproducing those of the intact knee than any other femoral component position. The high lateral ridge on the femoral component effectively prevents patellar dislocation but may produce abnormally high stresses on the patellar implant, especially if the implant is medially displaced or internally rotated. This could lead to accelerated wear or loosening of the patellar component.

Aged↗
PubMed1996

[Surgical treatment for recurrent dislocation of the patella in children and adolescents].

Over 100 surgical procedures for recurrent patellar dislocation is described in the literature. Soft tissue operations being less traumatic are specifically indicated in children and adolescents. This paper deals with three of them: Ali Krogius, Garlicki-Salamon and Blauth-Schwarz procedure. Material included 31 patients aged 8-21 years. Thirty-five operation were done: Ali Krogius procedure 14 times, Garlicki-Salamon 13 times and Blauth-Schwarz procedure in 8 cases. The four grade Hall and Michelli scale was used to assess the results. Excellent results were achieved in 12 cases, good in 19, fair in 4 and 2 were poor. Blauth-Schwarz procedure rendered the best results, the worst were accomplished with Ali Krogius operation.

Adolescent↗
PubMed1993

The Miller-Galante knee prosthesis for the treatment of osteoarthrosis. A comparison of the results of partial fixation with cement and fixation without any cement.

In a prospective, non-randomized study of 344 patients who had 392 primary total knee replacements with a Miller-Galante I prosthesis for the treatment of osteoarthrosis, the results of partial fixation with cement (insertion of the tibial and patellar components with cement and of the femoral component without cement) were compared with those of fixation without any cement. Of the 392 knees, 183 (163 patients) had fixation without cement (Group I) and 209 (181 patients), with and without cement (Group II). The average duration of follow-up was three years (range, two to five years). Nine patients died during the follow-up period, but no others were lost to follow-up. Analysis of the knee scores, range of motion of the knee, radiographs, and rates of complications revealed no differences between the outcomes in the two groups during the follow-up period. The rate of complications due to problems related to the extensor mechanism was high in both groups: a reoperation was performed in fifteen (8 per cent) of the knees that had had fixation without cement and in nineteen (9 per cent) of those that had had both types of fixation. Thirteen patients had additional operative treatment for recurrent patellar dislocations; twelve patients, for abnormal wear of the polyethylene of the patellar component: two patients, for avulsion of the patellar ligament from the tibia; and two patients, for unexplained pain in the knee. In addition, there were eight patellar fractures (two of which led to a reoperation) and three deep infections (all of which led to a reoperation).

Adult↗
PubMed2002

[Total knee arthroplasty: a 4.5-year follow-up].

OBJECTIVES: To present the short- and mid-term follow-up results of primary total knee arthroplasty. METHODS: We performed a total of 97 cemented total knee replacements (47 right, 50 left) with posterior cruciate ligament retention in 66 patients (60 women, 6 men). The mean age at the time of surgery was 65.2 years (range 29 to 82 years). Preoperative diagnoses were primary osteoarthrosis (n=60), rheumatoid arthritis (n=3), systemic lupus erythematosus (n=2), and post-traumatic osteoarthritis (n=1). Thirty-one patients had bilateral knee replacements, of which 29 were performed at the same session. Pre- and postoperative clinical evaluations were made according to the clinical rating system of the Knee Society. Radiographic evaluations were made according to the Fairbank's criteria preoperatively, and to the total knee arthroplasty radiographic evaluation and scoring system of the Knee Society postoperatively. The mean follow-up was 4.5 years (range 24 to 98 months). RESULTS: Clinical results were good or excellent in 94.8 percent of patients. Complications encountered were deep infection in two patients, patellar dislocation in two patients, deep venous thrombosis in two patients, and patellar tendon rupture in one patient. The mean increases in knee and functional scores were 42.94 and 39.87, respectively. Improvement in the mean postoperative knee flexion was 35.72 degrees. The mean leg alignment was 6.3 degrees valgus. No components required revision because of aseptic loosening. CONCLUSION: Posterior cruciate ligament retaining implants were found to yield successful clinical and radiologic results during short- and mid-term follow-up period.

Adult↗
PubMed1996

[Imaging of external instabilities of the patella. State of the art].

External femoropatellar instability is a dynamic abnormality from various origins: osseous, cartilaginous or musculotendinous; X-rays films cannot give a precise enough description of this phenomenon. Attention is drawn by anterior pain or a sensation of instability. Clinical analysis distinguishes between permanent, traumatic or transient dislocations which are now more frequently discovered as part of a femoro-patellar syndrome with or without cartilage involvement. Conventional imaging, CT-scan and MR imaging are based on faultless techniques. Lateral views precisely report femoropatellar architectural abnormalities and patellar instability. Skyline views are able to quantify the various parts of the dysplasia. Dynamic tests increase the sensitivity of the plain films. But the main shortcoming of these techniques is the lack of visualization of the initial patellar engagement in the trochlea. The femoropatellar component of the knee arthrography visualizes rather large cartilaginous lesions. CT-scan, better than skyline views, allows examining the patellar bone without interference with the trochlea (extended knee), during the engagement (15 degrees flexed knee) and after the engagement (30 degrees flexed knee). However, the examination technique varies from one author to another according to his own pathophysiologic understanding. With the bicondylar plane reference, the reliability of the CT-scan measurements are better than skyline views. Like the dynamic tests during the beginning of the patellar engagement at 15 degrees, flexion is more sensitive than those at 30 degrees. Finally, CT-scan arthrography demonstrates thinner cartilaginous lesions than conventional arthrography. Presently the main contribution of MR imaging consists of detecting transient patellar dislocation that a single clinical examination cannot differentiate from other internal knee disorders. MR imaging is more precise in analyzing the cartilaginous structure. Kinematic MR imaging, still in an experimental stage, offers a new approach to the dynamic study of the patellar tracking.

Humans↗
PubMedDate not supplied

Dislocated patella associated with below-knee amputation in adolescent patients.

One-third of the adolescent patients followed up in our prosthetic clinic have developed patellar dislocation. Four cases are described, and radiographs are evaluated for femoral-tibial alignment, patellar height, and tibial length. Patella alta was present in each patient. We propose that the forces associated with the patellar tendon-bearing prosthesis may produce elongation of the patellar tendon in young patients and predispose them to patellar instability.

Adolescent↗
PubMed1996

Effect of medial displacement of the tibial tubercle on patellar position after rotational malposition of the femoral component in total knee arthroplasty.

A large Q angle induced by technical error such as an internally rotated femoral component causes patellar failure after total knee arthroplasty. The effect of medial displacement of the tibial tubercle to decrease the Q angle for patellar tracking was studied by evaluating the patellar position relative to the patellar groove on the femoral component in cadaver specimens. A 5 degrees internally rotated femoral component caused the patella to shift medially about 5 mm, and also caused the tibia to rotate internally about 3 degrees at full extension. With a 5 degrees externally rotated femoral component, normal patellar tracking occurred. The distance of medial displacement was determined so that the patellar tendon was parallel to the longitudinal axis of the tibia at full extension. This allowed the quadriceps tendon, the patella, and the patellar tendon to form a straight line. The average distance of medial transposition of the tibial tubercle was 9.32 mm. Medialization of the tibial tubercle caused the patella to shift about 2 mm medially from the patellar groove. The transfer also caused an external rotation of the tibia (2 degrees-5 degrees). Medial transfer of the tibial tubercle changes patellar kinematics and corrects the tendency toward lateral patellar dislocation caused by internally rotating the femoral component; however, it also creates minor patellar and tibial kinematic changes that may have a clinical effect.

Biomechanical Phenomena↗