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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Modification of patella alta, patella ventralization en patella lateralization in patellar pain syndrome following implantation of total GSB endoprosthesis].

We examined the degree of retropatellar pain related to biomechanical factors of the implantation in 31 cases of GSB-endoprostheses without retropatellar alloarthroplasty, loosening or infection. Postoperative patella alta and lateralisation of the patella extended the retropatellar pain syndrom but not tibiaventralisation. These results indicate that certain unfavourable patella positions may be responsible for the retropatellar pain syndrom in patients with a GSB-endoprosthesis.

Adult↗
PubMed1994

Effects of patella alta and patella infera on patellofemoral contact forces.

The relationship between patella alta and patellar subluxation may, in part, reflect the relationship between the height of the patella above the tibiofemoral joint line and the patellofemoral contact force. This study reports on the direct in vitro measurement of the patellofemoral contact force, and its point of application on the patella, as a function of patellar height. The contact force was measured by a specially designed six-degree-of-freedom force transducer under loading simulating rising from a chair. The magnitude of the resultant contact force increased significantly with superior displacement of the patella. The magnitude of the resultant contact force changed as much as 3% per millimeter of change in patellar height. The details of this response varied among the knees tested and depended on the original anatomical patellar height. For a high-riding patella, the onset of tendofemoral contact is delayed and the magnitude of the patellofemoral contact continues to increase with increasing flexion angle. Early onset of tendofemoral contact associated with a low-riding patella results in a concomitant reduction in the magnitude of the contact force. The medially directed component of the contact force acting on the patella resists lateral subluxation of the patella. This force component increased with superior displacement of the patella. This may explain in part the tendency for a high-riding patella to sublux. For all seven specimens tested the point of application of the resultant contact force migrated superiorly with inferior displacement of the patella.

Aged↗
PubMed2002

Patella baja after total knee arthroplasty: is it really patella baja?

In the prosthetic knee, narrowing of the space between the patella and the tibial polyethylene can be due to distal positioning of the patella or to a proximal transfer of the joint line. In the former case, one is dealing with patella baja. In the latter case, the patella is in its normal position relative to the femur, a situation we call pseudo-patella baja. The therapeutic options for patella baja and pseudo-patella baja are different because the former is due to a short patellar tendon, and the latter is due to a raised joint line. Eversion of the extensor mechanism during revision surgery may be more challenging with true patella baja compared with pseudo-patella baja. It is important not to attempt to detect true patella baja with either the Blackburne-Peel or the Caton-Deschamps ratio in the setting of a prosthetic knee because these ratios are affected adversely by the position of the joint line.

Arthroplasty, Replacement, Knee↗
PubMed1993

Effects of patella taping on patella position and perceived pain.

Anterior knee pain syndrome (AKPS) represents a significant challenge for the sports medicine clinician. One proposed etiological factor for AKPS is poor vastus medialis obliquus (VMO) control, resulting in lateral glide of the patella. Patella taping has been advocated to increase VMO control. The purpose of this study was to determine the effects of patella taping on patella position and perceived pain. Twelve subjects (age = 29 +/- 9 yr; weight = 70.9 kg +/- 17.8; height = 174.0 cm +/- 8.1) with AKPS currently using patella taping procedures with a decrease in their symptoms participated. Each subject had Merchant's view x-rays taken pre- and post-taping while performing an isometric quadriceps contraction to determine patella rotation and patella congruency angles. Subjects also completed a visual analog pain scale after performing a 0.2 m (8") step-down both pre- and post-taping. Paired t-tests revealed no significant change in patellofemoral congruency (P = 0.98) and patella rotation angles (P = 0.80). Significant reduction (50%) in subject pain level was revealed by the visual analog scale (t(15) = 4.99; P < 0.0005). Results demonstrate that patella taping significantly reduced the perceived pain levels during a 0.2-m step-down; however, this reduction in pain was not associated with patella position changes.

Adult↗
PubMed2003

Patients with lateral tracking patella have better pain relief following CT-guided tuberosity transfer than patients with unstable patella.

In patients with either lateral tracking patella or unstable patella the pathological lateral position of the tuberosity can be corrected by a medial transfer. This study compared the results of subtle CT-guided correction of the tuberosity for objective unstable patella (n=27) with the results for lateral tracking patella (potential instability) as described by Dejour (n=16). Follow-up was 37 months. CT revealed a pathological lateralization of the tibial tuberosity-trochlear groove greater than 15 mm in 41 knees. These patients underwent medialization of the tibial tuberosity up to 10-12 mm lateral from the trochlear groove, and 28 patients underwent a distalization to normalize the Caton index to 1.0-1.2. Results were evaluated using Cox' method. Patients with objective patellar instability were rated as 11% excellent, 52% good, 33% fair, and 4% poor. All patients became stable except one who had a 6 degrees valgus alignment. Although 96% had improved stability, 33% of the patients still had pain. The patients with lateral tracking patella (potential instability) were rated as 37.5% excellent, 44% good, and 19% fair. The lower proportion of pain relief in patients with unstable patella is likely the result of the cartilage damage experienced by these patients following multiple dislocations. Thus the patient with lateral tracking patella without patella dislocations must be differentiated from the one with unstable patella. Their prognosis in pain relief is better.

Cohort Studies↗
PubMed1999

Surgical management of congenital permanent dislocation of the patella in nail patella syndrome by Stanisavljevic procedure.

We report a patient with nail patella syndrome associated with congenital permanent dislocation of the patella successfully operated on using a modified Stanisavljevic method. The patient, a 26-year-old woman, complained of inability to completely extend her right knee joint. She had occasionally experienced the "giving way" phenomenon since childhood, but she had not received any treatment since birth. Physical examination showed that all fingernails were deformed, with longitudinal striations, while the lunules were of an abnormal triangular shape or were missing. Both patellae were palpably hypoplastic, with the right patella dislocated laterally, and the knee had an extension lag of 90 degrees. Thigh and leg muscle were slightly underdeveloped, but quadriceps muscle contraction was good. Several radiographs were taken and they showed bilateral iliac horns and hypoplasia of the bilateral humero-radial joints and of both patellae, and complete dislocation of the right patella. We employed the Stanisavljevic procedure for the reduction of the patella, with Z-lengthening of the rectus femoris and medial translocation of the tibial tuberosity. Four years after the operation, a 30-degree extension lag still exists in the right knee, but the treatment resulted in stable alignment of the quadriceps mechanism, and notably improved gait appearance.

Adult↗
PubMed2000

Effect of a patella-stabilizing brace on lateral subluxation of the patella: assessment using kinematic MRI.

This study investigated the effect of a special patella brace on patients with lateral subluxation of the patella using kinematic magnetic resonance imaging (MRI). Fifteen patients were assessed with and without application of the brace (Shields Patella Stabilizing Brace, Hely & Weber, Santa Paula, Calif) using active-movement, against-resistance kinematic MRI of the patello-femoral joint. Kinematic MRI examinations were evaluated using previously described qualitative criteria to determine patello-femoral relationships. Eleven (73%) patellofemoral joints had improvement (55%) or correction (45%) of lateral subluxation of the patella. The brace failed to alter the position of the patella in four (27%) patients who had patella alta (two patients) or were extremely overweight (two patients). This study provided objective findings that application of the brace improved or corrected lateral subluxation of the patella in the majority of patients. This information has important implications for the conservative treatment of patients with this form of patellar malalignment.

Adult↗
PubMed1975

Patella alta and patella infera. Their etiological role in patellar dislocation, chondromalacia, and apophysitis of the tibial tubercle.

The Insall-Salvati method of assessing the position of the patella was applied to four groups of patients:normal patients, and those with dislocation of the patella, chondromalacia of the patella, and apophysitis of the tibial tubercle. The ratio of patellar length to tendon length was 1.0 in the normal patients, 0.8 in the patients with dislocations, 0.86 in those with chondromalacia, and 1.2 in those with apophysitis of the tibial tubercle. Patella alta may be an important cause of dislocating patella and of chondromalacia patellae. The significance of the patella infera found in the Osgood-Schlatter lesion may be one of either cause or effect.

Adult↗
PubMed1982

[Critical study of patella alta. II. Patella alta and femoropatellar pathology].

Patella alta is radiologically defined by an Insall index equal to or greater than 1.3. In 50 patients suffering from pain of the femur and patella, roentgenographic studies consisting of a simple profile view and occasionally completed by a view through Smillie's angle with the knee hyperextended, revealed patella alta. The stretching of the patellar tendon is facilitated by excessive tension during growth and by excessively strenuous physical exercises; patella alta can occasionally be complicated by Osgood-Schlatter's or Sinding-Larsen Johansson's disease. Ruptured tendons have occasionally been observed. Genu recurvatum can also lead to patella alta. The joint should be routinely examined for excessive mobility. Patella alta is often associated with various affections of the extensor apparatus of the knee: pathology secondary to injury, external malposition, gonarthrosis, supratrochlear erosions of the femur. The importance of the role of this condition with respect to patellar chondromalacia has been estimated to varying degrees. The diagnosis of patella alta should be considered in all cases of knee pain.

Adolescent↗
PubMed1997

Radiographic changes in the patella after total knee arthroplasty without resurfacing the patella. Comparison of osteoarthrosis and rheumatoid arthritis.

The necessity of patellar resurfacing has aroused considerable controversy. Between 1986 and 1996, we have routinely performed 208 primary total knee arthroplasties (TKAs) without resurfacing the patella. However, we have occasionally observed gradual postoperative patellar deterioration which caused peripatellar pain. This study observed the radiographic changes in the patella after TKA without resurfacing the patella to assess the effect of the changes on the clinical results. Sixty out of 208 TKAs were assessed in this study. The original diagnoses were osteoarthrosis (OA) in 17 joints and rheumatoid arthritis (RA) in 43 joints. Fourteen patients (23.3%) complained of postoperative peripatellar pain: 2 of the 17 patients with OA (11.8%) and 12 of the 43 with RA (27.9%). Lateral tilt of the patella slightly decreased with time, but lateral shift increased slightly. Patellar length and width increased throughout the follow-up period. The thickness of the patella, especially in the RA cases, significantly (Mann-Whitney, p < 0.05) decreased with time. According to these radiographic findings, as time passed the thickness of the patella decreased, its length and width increased, and the patella as a whole became flattened. On examining the effect of this flattening on postoperative pain, it was found that about 70% of those patients whose patellar thickness had decreased to 80% or less complained of peripatellar pain. In the case of the OA patients, however, there was no statistically significant correlation between patellar flattening and pain. It is concluded that patellar resurfacing should be considered for the patient with rheumatoid arthritis. Because patellar flattening did not develop in many patients with OA and few of them complained of peripatellar pain, patellar resurfacing should not be performed routinely.

Activities of Daily Living↗
PubMed1982

[The patella following implantation of a knee prosthesis, with reference to patella plasty (author's transl)].

The follow-up patella using knee prosthesis depends on the followings: a) advancement of femoropatellar arthrosis, b) shape and kind of surface of the fossa patellaris femoris, c) kind of knee prosthesis. To treat the patella arthrosis patella plasty is a good alternative to a patella prosthesis. This has been noticed by good or very good results 34 Patients out of 43. It has no complications and does not prevent the use of patella prosthesis if necessary.

Bone Regeneration↗
PubMed1987

Dorsal defect of the patella: concept of its origin and relationship with bipartite and multipartite patella.

In a series of 2286 single radiographic examinations of the knee in 1985, 6 dorsal defects of the patella (DDP) were detected. The diagnosis was made if a round lucent lesion of the dorsal superolateral surface of the patella was found abutting against articular cartilage. In four of our patients, an association with a multipartite patella (MP) was found. Biopsy of one lesion showed dense connective tissue and areas of bone necrosis. In one patient, the pattern of reossification of the lesion could be demonstrated. Our observations provide further evidence that the DDP is a stress-induced anomaly of ossification rather than a post-traumatic subarticular cyst of the patella, a diagnosis sometimes suggested by the clinical context. The initial lesion is probably a traction lesion at the insertion of the vastus lateralis muscle rather than ulceration of articular cartilage. We suggest a possible relationship between dysfunction of the quadriceps mechanism, patellar subluxation, and the genesis of the DDP.

Adolescent↗
PubMed1992

[Importance of the subchondral space for development of chondromalacia patellae--morphologic study of joint cartilage of the rabbit patella after experimental ischemia].

The aetiology of chondromalacia patellae and especially the importance of the subchondral space have not been clarified to date. However, clinical findings yielded pointers to a connection between degenerative changes of the articular cartilage and an influence exercised by the subchondral space. In our experiments we performed an operative ischaemia of the patella with interruption of the vascular inflow and outflow on 40 adult rabbits for exactly defined times (2 weeks, 6 weeks, 3 months, 6 months). The examinations were carried out using the plastination method, histology, transmission electron microscopy, and scanning electron microscopy. Marked changes can be seen from the third month onwards: disappearance of the tidemark, degeneration of the cartilaginous cells (formation of clusters) and onset of trachomatous keratitis. These degenerative changes progress further in the animals of 6 months of age. The results indicate that metaplasia of the tidemark plays a significant part in the pathogenesis of degenerative changes of the cartilage. Hence, chondromalacia patellae can be caused by subchondral vascularisation disorders.--This is, therefore, a new concept for the aetiopathogenesis of chondromalacia patellae, a disease pattern that is of great importance in sports orthopaedics.

Animals↗
PubMedDate not supplied

[Patellofemoral pressure and contact surface measurement in the 'hunter's hat patella'. Experimental studies of sagittal patella osteotomy].

One reason of the chondromalacia patellae is the functional incongruence due to a patellofemoral dysplasia like for example the so called hunter's hat deformity. As a curative treatment in those cases an osteotomy of the patella may be carried out. This operation shall improve the congruence of the articular surface as well as the stability of the patella. There are experimental studies describing the femoropatellar pressure situation in eight cases with a surgical induced hunter's hat patella after osteotomy. The results represent a significant increase of the opposing surfaces in the medial compartment and a more uniform distribution of the femoropatellar pressure.

Cartilage Diseases↗
PubMed1980

A study of the arterial supply of the patella in the normal state, in chondromalacia patellae and in osteoarthrosis.

The arterial supply to the patella has been studied in 21 specimens. Fifteen were obtained at autopsy and six at amputation. Nine of the specimens were normal, six were diagnosed as chondromalacia patellae and six as osteoarthrosis. Micropaque was injected into the arteries, and the Spalteholtz clearing technique was used. Radiography was also performed. In addition to previously reported observations, arteries were found to penetrate into the patella from the interior of the quadriceps tendon, from the synovial tissue and from the medial and lateral retinaculae. Moreover, it was found that with increasing degree of cartilage destruction the arterial pattern within the patella became disturbed and irregular with formation of anastomoses.

Adult↗
PubMed1992

Patella alta and recurrent dislocation of the patella.

Fifteen knees were treated with a surgical technique designed for recurrent patellar dislocations when associated with patella alta. The average number of patellar dislocations preoperatively was 12, and the determination of patella alta was made using the technique described by Insall and Salvati, which is a ratio of the length of the patellar tendon to the longest diagonal length of the patella. The normal value for this ratio is 1.02 plus or minus 20%. The average preoperative ratio in this study was 1.58 (range, 1.2-2.1), which changed to 1.08 (range, 0.99-1.14) by the time of follow-up examination. The surgical technique used involves transposing the patellar tendon insertion distally without any medialization or recessing and allows for good bone contact for healing, secure fixation, and immediate postoperative motion. There were no recurrences of patellar dislocation postoperatively and few complications. Only one patient complained of anterior knee pain in the follow-up period. This technique is thought to give good results when it is used specifically for recurrent patellar dislocations associated with patella alta.

Adolescent↗
PubMed2003

Use of a trabecular metal patella for marked patella bone loss during revision total knee arthroplasty.

This study evaluates the short-term results following patellar resurfacing with a trabecular metal patella shell in the setting of marked patellar bone loss at the time of revision total knee arthroplasty (TKA). Twenty consecutive patients undergoing revision TKA with the use of a trabecular metal patella were evaluated at a mean 23-month follow-up. All patients had marked patellar bone loss at surgery precluding resurfacing with a standard cemented patellar button. Results were good or excellent in 17 of 20 patients. There were no displacements of any trabecular metal patella shells, and the fixation appeared excellent despite the poor quality of bone remaining. Complications included 3 patients with polar patella fractures postoperatively. Qualitatively, these results compare favorably with patellar resection arthroplasty in this setting.

Adult↗