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PubMedDate not supplied

Instrumented measurement of patellar mobility.

To provide an objective analysis of medial and lateral patellofemoral laxity, we examined 94 uninjured athletic subjects and 22 patients with unilateral lateral patellar dislocation. We developed an instrument to measure the compliance of the medial and lateral patellar restraints. The instrument recorded the force-displacement relationship as the patella was pushed medially and laterally. Subtracting the medial displacement from the lateral displacement at a given force level allowed the tester to assess the peripatellar soft tissue "balance." The results for both the 2.5- and the 5-pound tests were significant. Paired comparisons differentiated the three groups, with significant differences between control and affected (P = 0.0001), control and contralateral (P = 0.0036), and affected and contralateral (P = 0.0157) knees. The mean result of the lateral minus medial displacement test for our sample population of control subjects was -2.1 mm for the 5-pound test. A negative value in this test indicates that medial displacement exceeds lateral displacement. This finding was present in 81% of control subjects. In contrast, the mean result for the patients' affected knees was +3.2 mm for the 5-pound test. Using the value of 0.0 mm as the diagnostic determinant for peripatellar imbalance, we found a test sensitivity of 91% and a specificity of 81%.

Adolescent↗

PubMed1994

Clinical comparison of the Miller Galante I and AMK total knee systems.

One hundred patients with primary osteoarthritis of the knee were prospectively randomized to assess the clinical outcome between two contemporary knee designs, namely the Anatomic Modular Knee (AMK, DePuy, Warsaw, IN) and the Miller Galante I (MG I, Zimmer, Warsaw, IN). In addition, patients were stratified by surgeon. While the clinical outcome measured by the Hospital for Special Surgery knee scores was similar for both groups, there was a difference in the number of complications requiring further surgery. Extensor mechanism complications requiring further surgery occurred in four patients (3 MG I and 1 AMK); three patients in the MG I group required a distal realignment procedure for patellar dislocation, while none of the AMK patients had this complication. There was, however, one patellar fracture in the AMK group that required an open reduction. The authors postulate that the major difference contributing to patellofemoral complications relates to the patellofemoral design and patellar tracking, with the more anatomic AMK femoral component having better patellar tracking and stability clinically.

Aged↗

PubMed1987

[Dislocation of the patella--causality in legal accident insurance].

Fifty-two expertises on connections between cause and effect of patellar dislocations were examined with a view to improving the standards of medical expertizing. On principle, the mechanism of injury is the decisive criterion in determining whether the injury can be considered capable of causing the dislocation. It was found that in about one-half of the cases the dislocation was wrongly attributed to the event and that a reasonable connection existed in only one-quarter of the cases. The typical causes of error in reasoning - first dislocation, impressive pattern of injury, no degenerative changes - are listed and discussed. The importance of the pattern of damage for the first occurrence of a dislocation is demonstrated. The suitability of different courses of events for contributing essentially to the dislocation is discussed.

Adolescent↗

PubMed1990

Acute dislocation of the patella. A prospective review of operative treatment.

We report a prospective study of 55 patients with acute primary patellar dislocation, all treated by operation and followed up for at least two years. Diagnosis was based on the history of a lateral displacement, with medial tenderness and a positive apprehension test; redislocations were excluded. Before operation, the difference in lateral shift on skyline views of the injured and control patellae was highly significant. At operation, rupture of the medial retinaculum of the patella was seen in all but one case. There were medial marginal fractures of the patella in 23 cases. Subjective results of the operation were excellent or good in 44 of the 55 at two years with a redislocation rate of only 9%. Most patients were able to return to the same level of sporting activity as before the injury.

Adolescent↗

PubMed1995

Results in the treatment of recurrent dislocation of the patella after 30 years' follow-up.

The authors compare the clinical and radiographic outcome in patients with comparable bilateral recurrent patellar dislocation treated surgically on only one side, to clarify the appropriateness of the surgical indication. Sixteen patients were evaluated at an average follow-up of 30 years (20-45); all had been treated by the Roux technique. The results on both the operated and the unoperated knee were evaluated; the Crosby and Insall schedule was used for the clinical evaluation. Anteroposterior, lateral, and Merchant's view X-rays were examined for osteoarthritis and to measure the height of the patella. The congruence angle and the distance between anterior tibial tuberosity and trochlear groove (ATT-TG) were measured by computed tomography. The results in the operated knees were: 3 excellent, 9 good, 1 fair, and 3 worse; results in the nonoperated knees were 6 excellent, 8 good, 1 fair, and 1 worse. In the operated knees arthritis was grossly marked in 8, marked in 3, moderate in 1, and light in 4; in the nonoperated ones it was grossly marked in 8, moderate in 3, and light in 5. The congruence angle was normal in 10, medially displaced in 3, and laterally displaced in 3 cases on the operated side; on the nonoperated side it was normal in 7 cases and lateralized in the remaining 9. The ATT-TG in the operated knees was negative in 9 cases, normal in 1, and positive in 6; on the non-operated side it was positive or normal. In 7 operated cases a low patella was documented. The Roux technique yields positive results in the correction of recurrent dislocation. No clinical or radiographic differences were found between surgically and conservatively treated knees. The clinical results are generally not comparable with the radiographic features or with severity of degenerative modifications presented at long-term follow-up. The absence of a difference is due basically to the complete lack of adaptation of the surgical procedure to the variable pathogenesis of this disorder.

Adolescent↗

PubMedDate not supplied

Effect of a patellar realignment brace on patients with patellar subluxation and dislocation. Evaluation with kinematic magnetic resonance imaging.

The object of this study was to evaluate the effect of a patellar realignment brace on patients with patellar subluxation or dislocation. Twenty-one patients (24 patellofemoral joints) with clinical evidence of patellar subluxation (N = 16) or dislocation (N = 5) were examined with the joint inside a positioning device to allow active-motion, kinematic magnetic resonance imaging. To analyze the patellar tracking pattern, the same imaging parameters (patellar tilt angle, bisect offset, and lateral patellar displacement) and section locations were used before and after application of a patellar realignment brace. No statistically significant differences were found in any of the three parameters for the patellofemoral relationships before or after wearing the patellar brace. The results indicated no stabilizing effect of the tested brace in patients with patellar subluxation or dislocation during active joint motion.

Adolescent↗

PubMed1993

Acute dislocation of the patella: MR findings.

PURPOSE: The authors describe magnetic resonance (MR) imaging findings of acute traumatic dislocation of the patella. MATERIALS AND METHODS: MR imaging at 0.1 T was performed in 25 patients with an acute patellar dislocation, 24 of whom underwent surgery. All patients were young male conscripts, aged 18-22 years. RESULTS: Signal intensity abnormalities of bone, seen as areas of decreased signal intensity on T1-weighted images, were found in all 25 patients (100%). The lateral femoral condyle was involved in all cases. Signal intensity changes also appeared in the patella in eight patients and in the lateral tibial plateau in three. Osteochondral fragments seen at plain radiography and cartilage fissuring noted at arthroscopy were not visible at MR imaging. Injury of the medial patellar retinaculum was seen at MR in each case. All patients had a joint effusion. Lateral subluxation of the patella was a common finding. CONCLUSION: Constant findings at MR imaging were (a) contusion of the lateral femoral condyle, (b) tear of the medial retinaculum, and (c) joint effusion.

Acute Disease↗

PubMed1994

[Posterior luxation of the tibia on total knee prosthesis: apropos of 6 cases].

PURPOSE OF THE STUDY: Posterior dislocation of Total knee arthroplasty is an infrequent but serious complication. Six cases of this complication were treated from 1979 to december 1993, all occurring on primary arthroplasties. MATERIAL AND METHODS: Knee arthroplasty was performed once for rheumatoid arthritis, five times for osteoarthritis. All cases occurred with a semi constrained prosthesis sacrifying posterior cruciate ligament: 2 Total condylar without posterior stabilisation, and 4 posterior stabilised prosthesis. In one case the dislocation occurred on a very severe rheumatoid arthritis: the patient, confined in a wheel chair, was not reoperated. In two patients, the dislocation was due to rotatory malposition of the tibial component. In the last three cases, we did not found any cause to the dislocation, except ligament laxity: 2 of these patients had, pre operatively, a valgus deformity. In 6 cases, we found only 2 problems on extensor system (one patellar dislocation and one patellectomy). RESULTS: 5 patients required a surgical treatment In 2 cases, we used a more constrained prosthesis, with poor results, but the knee was stable. Once, by changing the position of the tibial component, and using a thicker plate. In 2 patients we only put a thicker tibial polyethylene component. These 3 patients had a good stability: 2 have an excellent result with H.S.S. rating system, the third one has a poor result explained by patellar pseudoarthrosis occurring after traumatic patellar fracture. DISCUSSION: With our patients and cases published in North American works, we have studied the different mechanisms of such a posterior dislocation: rotatory disorder on tibial component, ligament laxity in flexion, extensor system deficiency, valgus deformity with important postero lateral release. CONCLUSION: The causes of posterior dislocation on Total knee arthroplasties must be known: we have to try to prevent such a complication. If it occurs, a precise analysis will permit a logical curative treatment, which must avoid constrained prosthesis.

Aged↗

PubMedDate not supplied

Total knee dislocation due to rotatory malalignment of tibial component: a case report.

Dislocation of a total condylar knee replacement occurred because of rotatory malposition of the tibial component. The dislocation was evaluated by open operation and in the laboratory. It can be prevented by: directing the tibial component at the tibial tubercle; not using the posterior edge of the tibia to align the tibial component; recognizing the "contradictory rotation" of the tibia. At operation the tibia externally rotates with flexion and lateral patellar dislocation for exposure. However, the screw-home mechanism in normal gait causes the tibia to internally rotate with flexion. This difference of rotation increases the likelihood of dislocation. Other problems caused by rotatory malposition of the tibial component are: patellar subluxation in a hinged knee prostheses; patellar malalignment, patellar pain and possible prosthetic patellar loosening; abnormal eccentric loading of the tibial component and subsequent tibial-component loosening in all knee prostheses.

Humans↗

PubMed1979

Patellar complications following total knee arthroplasty.

We studied the complications involving the patella following total knee arthroplasty in eighty-six knees in which thirty-four unconstrained and fifty-two offset hinge prostheses had been implanted. The abnormalities that we studied included: patellar dislocation, five knees; subluxation, eighteen knees; localized wear, three knees; and generalized wear, four knees. In twenty-three patients these complications were associated with patellar malalignment, and occurred predominantly when the offset hinge model of prosthesis was used. The complications were attributed partly to mechanical factors inherent in the prosthetic design and partly to anatomical abnormalities. Failure of the surgeon to compensate adequately for both of those factors at the time of operation was a factor in most of the complications.

Aged↗

PubMed2002

Press-fit metal-backed rotating patella: seven- to 14-year followup.

A consecutive series of 80 patients with 110 press-fit metal-backed rotating platform patella resurfacing surgeries were reviewed at an average of 107 months followup (range, 84-167 months). Twenty-eight patients died before followup. Fifty-two patients (70 patellae) were available for clinical and radiographic followups. One patella was revised for failure of the patella component. Four patellae were revised along with revision of the knee replacement. One patella realignment procedure was done for recurrent subluxation of the patella. There were no patellar dislocations in this series, no patella fractures, and no disruption of the quadriceps tendon or infrapatellar ligament. Six patellae had subluxation seen on postoperative radiographs. The incidence of patellar tilt greater than 5 degrees was 13%. No patellae were considered radiographically loose. The incidence of radiolucencies was 37%. Subsidence of the component superiorly was identified in 39% of the patellae, and inferiorly in 36% of the patellae. Of the 49 patients (67 knees) returning for followup, 70% of the knees were rated as excellent, 10% were rated good, 15% were rated fair, and 5% were rated poor. Press-fit metal-backed patella provided good component durability with only one revision because of component failure. Radiographic analyses showed a high incidence of subsidence associated with good clinical results.

Aged↗

PubMed1993

Magnetic resonance imaging of patellofemoral relationships.

Patellofemoral relationships were analyzed in 11 patients (13 knees) with patellar dislocation and 15 asymptomatic subjects (15 knees) at 0 degree and 20 degrees of flexion. The measurements were made from five consecutive axial images through the patellofemoral joint. The six indices measured were lateral patellar tilt (LPT), lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), patella-lateral condyle index (L/PW), congruence angle (CA), and sulcus angle (SA). The reproducibility of the method was evaluated. The difference between the two study groups was more evident at 0 degree than at 20 degrees of knee flexion. Significant differences were noted between measurements made at different levels of the joint, particularly in the controls. Isometric contraction of the quadriceps muscle lateralized and tilted the patella slightly in both groups. L/PW with and without quadriceps muscle contraction, and LPA with reference to the anterior condyles differentiated between the two study groups most clearly. LPT and LPA with reference to the anterior condyles differentiated the study groups better than LPT and LPA with reference to the posterior condyles. The reproducibility was good except for inter-observer comparison of CA and SA. The use of an imaging plane selected at the midpoint of the patellar articular cartilage increases the sensitivity of the measurements, since it takes into account both the height of the patella and the tendency towards lateralization. These results indicate that patellar tilt is best measured with the LPA index and patellar lateralization with the L/PW index at 0 degree knee flexion. This study should always include isometric contraction of the quadriceps muscle.

Adolescent↗

PubMed2003

Nail-patella syndrome: long term evolution.

Nail-patella syndrome is a rare dysplasia characterized by a typical tetrad: hypoplasic nails, hypoplasic or absent patella, radial head dislocation and iliac horns. We review eight patients, four men and four women, aged from 20 to 70 years. The main complaint at consultation was with their knees due to patellar instability and pain. Five of them required surgical treatment due to patellar dislocation and three patients were not treated. The Krogius-Lecène procedure was performed in four patients with a good result following the Insall classification of pain and instability and with an average follow-up of 24 years (range, 18-28 years). Patellectomy was performed in the eldest patient due to femoropatellar arthritis present at first consultation. No patients presented with elbow or nail disorders or with iliac horns.

Adult↗

PubMed1991

[Femoro-patellar instability in children and adolescents].

93 knees in 74 patients between 9 and 20 years of age were operated because of patello-femoral instability. In 76 cases, it was due to an intractable patello-femoral syndrome and in 17 cases one or several episodes of patellar dislocation had occurred. Treatment consisted, after failure of physical therapy, 14 times in a leavering of vastus medialis with a lateral capsular release and medial capsularrophy. In 71 cases it was associated to a medial transfer of the patellar ligament. Results were studied in 85 knees after an average follow-up of 6 years. 45 knees were completely symptomless, an excellent result. 34 knees remained with some kind of pain and 6 patellae redislocated. It is concluded that the transfer of the patellar ligament should be associated to the dynamic realignment achieved by the vastus medialis transfer for better results.

Adolescent↗

PubMedDate not supplied

The three-in-one proximal and distal soft tissue patellar realignment procedure. Results, and its place in the management of patellofemoral instability.

The three-in-one procedure for extensor mechanism realignment of the knee combines lateral release, vastus medialis obliquus muscle advancement, and transfer of the medial one-third of the patellar tendon to the tibial collateral ligament. We observed 37 patients (42 knees) receiving this treatment at a minimum 25-month follow-up (range, 25 to 85 months; mean, 44). Thirty-two of 42 knees (76%) with recurrent patellar dislocation had good or excellent results after surgery. Redislocation occurred in four knees (9.5%). Skeletal immaturity, chondral damage, and generalized ligament laxity did not seem to affect outcome. Thirty patients (37 knees) were studied 2 years earlier as well (mean follow-up, 29 months). When comparing the results 2 years later, there was a significant deterioration in outcome over time. These results are comparable with the published results for other techniques of patellar stabilization. We describe the place of the three-in-one operation in our surgical protocol for patellofemoral instability, which is based on the principle that a procedure should be selected to address the underlying pathologic features in an individual case rather than always using one operation for all cases.

Adolescent↗

PubMed1990

[Arthroscopy of traumatic hemarthrosis following sports injuries. A 5 year analysis].

This retrospective study was made to evaluate the significance of different sports activities that cause variable haemarthrosis with intraarticular lesions of the knee joint. Throughout 1984 to 1988 arthroscopy was performed in 337 patients with acute haemarthrosis. The average time between trauma and arthroscopy was 8 days. ACL rupture was diagnosed in most of these cases. Regarding the different types of sport activities ACL lesions were found in skiers (74%), other winter sports (47%), soccer (53%), tennis and squash (58%), athletics (41%) and indoor (61%). Peripheral meniscus tears associated with haemarthrosis were found in 36% and patellar dislocations in 8%. Isolated MCL ruptures were diagnosed clinically and arthroscopy was not performed in these cases. Throughout 1987 isolated ACL ruptures were fixed by reattachment. This technique was not continued any longer and ACL replacement by patellar tendon as bone-ligament-bone was performed routinely since 1988 in those patients, who required surgery. 56 patients required ACL reconstruction following conservative treatment because of ACL deficiency, when they went back to sports activities. Longitudinal peripheral meniscus tears were fixed by the scape in inside-out technique.

Adolescent↗

PubMed1983

Effect of electrical stimulation to the vastus medialis muscle in a patient with chronically dislocating patellae. A case report.

Electrical stimulation to the vastus medialis muscle of a patient with chronically subluxing patellae prevented dislocation of the left patella during its application. No effect could be demonstrated while the stimulator was off. Other clinicians may, nonetheless, wish to adopt the method described in this article for assessing the efficacy of electrical stimulation on patellar dislocation, both while stimulation is applied and while it is not applied.

Adult↗

PubMed1996

Patella alta in southern China. A new method of measurement.

The position of the patella in the Southern Chinese population is 15 to 20% higher than in Western populations, both in controls and in disease. Those with patellar dislocation and anterior knee pain have significantly higher patellae than the controls in both population groups, and this is confirmed in the 5 methods of measurement we have studied. Patella alta is more common in our region. The patella alta index described in this paper provides a reliable and reproducible measurement of patellar height. A value of more than 3.4 is abnormal in our population.

Adolescent↗