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PubMedDate not supplied

Medial or lateral dislocation (snapping) of a portion of the distal triceps: a biomechanical, anatomic explanation.

Medial and lateral snapping (dislocation) of the distal triceps over the epicondyle during elbow flexion has been reported but is frequently misdiagnosed and is not well understood. In this study a mathematical model was designed to simulate the effect that bony abnormalities at the distal humerus and soft tissue variations of the distal triceps have on the line of pull of the triceps. The predictions were then tested on prefabricated and fabricated plastic elbow models, as well as 8 cadaveric elbows. When the bony alignment was altered, varus angulation had the greatest effect: 30 degrees varus malalignment of the distal humerus displaced the centroid of the triceps vector medially by approximately 2.0 cm. Valgus malalignment had a lesser effect: 30 degrees valgus displaced it laterally by 1.5 cm. Negligible effects on the triceps line of pull were seen with internal or external malrotation and with flexion or extension malalignment. Of the soft tissue alterations, displacement of the triceps insertion had a greater effect than movement of the triceps origin. The triceps vector was displaced by approximately 70% of the amount of translation of the triceps insertion. The relationship between the triceps line of pull and the bony alignment is represented by the triceps (T) angle. Our use of the T angle to understand snapping triceps is analogous to the use of the quadriceps (Q) angle for patellar subluxation/dislocation. Treatment should aim to restore normal triceps biomechanics with soft tissue or bony procedures.

Arm↗
PubMedDate not supplied

Lateral patellar luxation in miniature horses.

Bilateral luxation of the patella in four Miniature Horses was corrected by a lateral release incision and medial imbrication of the parapatellar fascia to the tendon of the sartorius muscle. Before surgery, the four horses had a grade 3 to 4 lateral patellar luxation bilaterally and had difficulty walking. Trochlear ridge hypoplasia was evident on radiographs in each horse. Follow-up information varied from 11 months to 4 years after surgery. Three horses had no patellar luxation or lameness. The other horse had a normal right stifle, but patellar luxation (grade 3) had recurred on the left.

Animals↗
PubMed1993

Patellar tracking patterns during active and passive knee extension: evaluation with motion-triggered cine MR imaging.

To evaluate the critical range of the patellofemoral joint motion from 30 degrees of knee flexion to full extension, motion-triggered cine magnetic resonance (MR) imaging was performed during active extension in 13 patients with confirmed patellar maltracking and 15 healthy subjects. Cine MR images were compared with static MR images obtained during incremental extension of the knee joint. To evaluate the patellar tracking pattern, the same imaging parameters (patellar tilt angle, bisect offset, and lateral patellar displacement) and section locations were used in the static and motion-triggered studies. Statistically significant differences between the passive and active knee motions were found in all three parameters in the group of patients and in the bisect offset in the control group. The comparison between patients and healthy subjects yielded statistically significant differences for all parameters in actively extended knees but not in passively extended knees. The results demonstrate the importance of dynamic patellar motion studies for diagnosis of patello-femoral maltracking.

Adolescent↗
PubMed2004

[Quadriceps and hamstring atrophy and weakness after knee trauma and treatment].

158 patients after the knee trauma and operational treatment were evaluated. Quadriceps and hamstring isometric strength and thigh circumference 10 cm above the patella were measured. Injured leg was compared to non-injured. PATIENT GROUPS: Group 1 - 43 patients with isolated ACL injury treated non-operatively. Group 2 - 29 patients after ACL reconstruction using Leeds-Keio prosthesis. Group 3 - 29 patients after subtotal arthroscopic meniscectomy. Group 4 - 13 patients with patellar fractures treated operatively and 6 weeks in long leg cast, Group 5 - 31 patients with proximal articular tibial fractures treated operatively and immobilized 6 weeks in long leg cast. Group 6 - 13 patients with distal femoral articular fractures treated operatively without immobilization. Group 7 - 10 patients with habitual dislocation of the patella after the Campbell-Goldwaith operation and 6 weeks in a long leg cast. CONCLUSIONS: 1) No significant correlation between the quadriceps and hamstring strength deficit and thigh atrophy was found. 2) Strength deficits concerns both quadriceps and hamstring muscles. 3) Strength deficits are higher in patients treated in the long leg casts than in non-immobilized.

Adult↗
PubMedDate not supplied

Comparison of trochlear block recession and trochlear wedge recession for canine patellar luxation using a cadaver model.

OBJECTIVE: To compare trochlear block recession (TBR) to trochlear wedge recession (TWR) with regards to patellar depth (percentage of patellar volume under the trochlear ridges), patellar articular contact, percentage of recessed trochlear surface area, and resistance to patellar luxation. STUDY DESIGN: In vitro computed tomography (CT) and biomechanical evaluation using a cadaver model. SAMPLE POPULATION: Twelve normal, large-breed canine cadavers. METHODS: Bilateral pelvic limb specimens with intact stifle joints were mounted on a positioning device. The femoral trochlear ridges were reduced to provide a standard shallow trochlea. TBR or TWR was performed to a standard depth randomly on paired specimens. CT and biomechanical evaluations were performed pre- and postoperatively in both an extended (148 degrees ) and flexed (113 degrees ) stifle position. CT images were digitized and measurements made using an image-analysis software program. Biomechanical testing consisted of applying 40 degrees of internal tibial rotation and documenting patellar luxation. RESULTS: The change in trochlear depth (depth of recession) was not significantly different between groups. In the extended stifle position (patella in the proximal trochlea), patellar depth and patellar articular contact with the recessed trochlea were significantly greater after TBR compared with TWR. The percentage of recessed trochlear surface area was significantly greater after TBR compared with TWR. In the extended position, a smaller percentage of the patellae luxated within 40 degrees of internal tibial rotation after TBR compared with TWR. CONCLUSIONS: TBR increases proximal patellar depth, increases patellar articular contact with the recessed proximal trochlea, recesses a larger percentage of trochlear surface area, and results in a greater resistance to patellar luxation in an extended position as compared with TWR. CLINICAL RELEVANCE: TBR may help limit the development of stifle DJD in dogs treated for canine patellar luxation.

Animals↗
PubMedDate not supplied

Operative realignment of patellar malalignment in children.

Realignment operations were performed on 57 knees to correct patellar malalignment in children between 1985 and 1991. Three different operative techniques were used: the lateral release, the lateral release and medial reefment, and the Roux-Goldthwait patellar tendon transposition. Roentgenographic values were measured before and after the operation by Laurin's method. The mean follow-up time was 4 years 2 months, after which 20 knees were excellent, 20 good, 11 fair, and six poor, according to Insall's criteria. The effect of the operation on pathological roentgenographic values was obvious, and the malalignment of the patella was in most cases corrected. There are differences in the improvement effected by these three techniques. The lateral release and medial reefment correct the patellar tilt most effectively, and the Roux-Goldthwait operation, the lateral patellar deviation. The lateral release seems to be the appropriate technique for mild malalignment.

Adolescent↗
PubMed1997

Changes in articular cartilage in experimentally induced patellar subluxation.

OBJECTIVES: Patellar subluxation was experimentally induced in young rabbits and the resulting cartilaginous changes were observed over a prolonged period of time to determine histological changes in the subluxated patellar cartilage. METHODS: The tibial tuberosity in 12 week old rabbits was laterally displaced and fixed to the tibia with wire to induce lateral patellar subluxation. Pathological changes in patellar cartilage were examined for 120 weeks after surgery using computed tomography and stereoscopic microscopy. RESULTS: Eight weeks after surgery, changes in articular cartilage consisting of horizontal splitting of the matrix were observed in the intermediate zone and were presumed to have been caused by shearing stress applied to the patellar cartilage. The cartilaginous changes caused by patellar subluxation progressed very little over the 120 weeks. Very few rabbits presented with osteoarthritic changes in the patellofemoral joint, most probably because the stress resulting from the malalignment of the patellofemoral joint was mild enough to permit recovery. CONCLUSION: The mild, non-progressive pathological changes, in particular, basal degeneration, induced in this experiment in patellar cartilage were quite similar to the changes in articular cartilage seen in human chondromalacia patellae.

Animals↗
PubMed1992

Patellar complications after knee arthroplasty. A prospective study of 56 cases using the Kinematic prosthesis.

A prospective study on 56 knees was performed to analyze the incidence and cause of patellar complications following total knee arthroplasty with the Kinematic prosthesis inserted with the Universal Instrumentation system. Patellar complications occurred in 23 cases: 15 had anterior knee pain. There was 1 case of patellar fracture. Subluxation of the patella occurred in 13 cases, of which 6 were painful. Although the mechanical alignment was correctly reconstructed to neutral in all but 2 cases, the instrumentation tended to allow malpositioning of the components into excessive femoral valgus and compensatory excessive tibial varus that predisposed to patellar subluxation. With this prosthesis and instrumentation, patellar stability is hindered by a very short anterior femoral flange, a shallow patellar groove, and insertion of the components at 3 degrees to the mechanical axis. It should be ensured that the components are correctly positioned, that patellar stability is carefully checked before closing the capsule, and that lateral release is performed more often.

Aged↗
PubMed2005

An unusual rotational injury: Pantibial ligamentous injury.

Pantibial ligamentous injury including knee dislocation and tibiotalar joint subluxation is an uncommon severe rotational injury. A 21-year-old male injured his right knee falling from a motorcycle. Physical examination revealed effusion on the right knee and ankle, and posterior translation of the tibia as well. The MRI of the right knee and ankle demonstrated the following findings: a complete disruption of cruciate ligaments, the medial collateral ligament, posteromedial corner injury together with a peripheric tear in the medial meniscus, the ruptured deltoid ligament, ankle syndesmosis space widening (>5 mm) and lateral subluxation of talus. Deltoid ligament of the right ankle was repaired and ankle syndesmosis was fixed with a cortical screw. The PCL and ACL were reconstructed arthroscopically with autogeneous bone-patellar tendon-bone graft. The midsubstance tear of MCL, posteromedial corner and medial meniscus tear were primarily repaired with nonabsorbable sutures. 3 years after the surgery, the patient was called for the final examination. MRI and X-ray findings of the knee and ankle joint demonstrated the continuity of ACL, PCL, MCL, and deltoid ligament. The patient, who is a farmer, can go back to his job and perform his daily activities. We presented a previously unreported case that involves both simultaneous occurrence of knee dislocation and tibiotalar joint subluxation. We used the term "Pantibial ligamentous injury" for this case.

Accidental Falls↗
PubMed1995

Effect of a newly designed patellar realignment brace on patellofemoral relationships.

The effect of applying a newly developed patellar realignment brace to a patient with lateral subluxation of the patella was evaluated using active movement, loaded kinematic magnetic resonance (MR) imaging. The brace corrected the lateral displacement of the patella as shown on the kinematic MR imaging study. The patient underwent physical rehabilitation in conjunction with the use of the patellar realignment brace and has had resolution of her painful symptoms for the past 4 months.

Adult↗
PubMedDate not supplied

Anteromedial tibial tubercle transfer in patients with chronic anterior knee pain and a subluxation-type patellar malalignment.

We performed a prospective analysis of 29 Fulkerson anteromedial tibial tubercle transfers in patients with chronic anterior knee pain. The average followup was 32 months (range, 25 to 44). Fourteen patients (Group 1) had subluxation-type malalignment (congruence angle > 20 degrees, tilt angle > 8 degrees) and were treated with an isolated anteromedial tibial tubercle transfer. Fifteen patients (Group 2) had combined subluxation and tilt malalignment (congruence angle > 20 degrees, tilt angle < 8 degrees) and underwent anteromedial tibial tubercle transfer combined with a lateral release. Pre- and postoperative evaluations included clinical and radiographic examinations, Lysholm and Kujala patellofemoral scores, and standing-alignment computed tomography scans in 15 degrees of flexion taken transversely at the midpatellar. In all but one patient a dramatic improvement in Lysholm and Kujala scores was noted. The congruence angle improved in all patients except one, with an average improvement of 16 degrees in Group 1 and of 14 degrees in Group 2. The tilt angle remained relatively unchanged (change, -0.5 degree) in Group 1, but it improved by 11 degrees in Group 2. We conclude that an isolated anteromedial tibial tubercle transfer can consistently improve patellar subluxation and, when combined with a lateral release, can improve patellar subluxation and tilt, resulting in improved functional scores for patients with chronic anterior knee pain.

Adolescent↗
PubMed1998

Medial subluxation of the patella without previous lateral retinacular release.

This case presented a 17-year-old patient with persistent complaints localized to the right patellofemoral joint. Clinical examination demonstrated increased medial translation of the patella on manual stress. In contrast to previous published reports on medial patellar subluxation, this patient had not undergone prior lateral retinacular release. Arthroscopic examination documented medial tracking of the patella as well as excess medial translation. Imbrication of the patient's lateral patellar retinaculum centralized patella tracking and diminished medial translation on stress testing as observed arthroscopically and clinically. This case illustrates that medial patellar subluxation is a subtle problem that may be overlooked in the patient presenting with patellofemoral complaints and should be included in the differential diagnosis.

Adolescent↗
PubMed1989

[Patellar fractures. Modified tension band osteosynthesis].

In a retrospective investigation, the ability of modified tension band osteosynthesis to retain 45 reduced fractures of the patella and the functional end result was studied. Postoperatively, 24 patients were immobilized in plaster casts for 0-14 days and the remainder for 25-56 days. Postoperative radiographs revealed nine fractures (four transverse, three comminuted and two pole fractures) with fragment displacements exceeding 2-3 millimeters. Among these, three fractures had secondary dislocation and, further, one exactly reduced pole fracture dislocated. Operation was complicated with infection in four cases: two superficial wound infections, one subcutaneous fistula and one pyarthron. Operative release of adhesions was performed in five cases, two patients were patellectomized and one required a condyle prosthesis. At follow-up 18-80 months after the injury, 37 patients were examined clinically. Among 29 patients without concomitant injuries, seven patients were free of symptoms and 13 patients were without any pain. Free knee movement and quadriceps atrophy less than or equal to 1.5 cm was found in 17 patients. The modified tension band can retain adequately reduced transverse and comminuted fractures of the patella, probably also without plaster immobilisation. Dislocated fracture of the patella is a serious lesion, which must be treated with care.

Adolescent↗
PubMed2003

Spondyloepimetaphyseal dysplasia with joint laxity leptodactylic form: clinical course and phenotypic variations in four patients.

We describe a 5-year-old boy and a 33-year-old woman with spondyloepimetaphyseal dysplasia with joint laxity leptodactylic form (spondyloepimetaphyseal dysplasia with multiple dislocations) (MIM 6003546), and two 12-year-old girls with the disorder who were previously reported as examples of a variant of sponatrime dysplasia. Their clinical manifestations included midface hypoplasia, micromelic short stature, and generalized joint laxity that caused multiple joint problems, including thoracolumbar scoliosis, hip subluxation, progressive genu valgum with knee and patellar subluxation, elbow subluxation, and malalignment of the wrist. Laryngotracheomalacia was present in two individuals, and myopathy was noted in one. The radiological findings in the four individuals included mild platyspondyly most conspicuous in infancy, narrow interpediculate distances of the lumbar spine evident in infancy, retarded epiphyseal ossification that evolved to epiphyseal dysplasia and later to degenerative joint disease, metaphyseal irregularities and striations present in early childhood, and leptodactylic appearance (slender short tubular bones) of the hand.

Adult↗
PubMed2002

World experience with low contact stress mobile-bearing total knee arthroplasty: a literature review.

This article reviews recent data regarding the low contact stress (LCS) mobile-bearing total knee prosthesis recently published in the literature; conclusions are based on literature controls. The LCS Total Knee System (DePuy Orthopaedics Inc, Warsaw, Ind) has addressed the issues of implant polyethylene wear and implant-generated osteolysis. Patellar implant complications have been minimal despite the use of a mobile, metal-backed component. The original US Food and Drug Administration clinical investigation demonstrated favorable experience with cementless fixation. Results from numerous series indicate that the main problem with a mobile-bearing device is an early prosthetic failure resulting from bearing dislocation or breakage. Inadequate surgical technique will lead to femorotibial malalignment or ligamentous instability, which are factors that commonly result in revision. With the LCS Total Knee System, surgeons can use a tibia-cut-first approach with careful ligamentous balancing and flexion block spacing. The valgus lateral knee approach is an additional technique that has proved useful with this method.

Arthroplasty, Replacement, Knee↗
PubMedDate not supplied

Evaluation of the Roux-Elmslie-Trillat procedure for knee extensor realignment.

One method for correction of patellofemoral malalignment in acute and recurrent dislocations and subluxations of the patella involves a lateral retinacular release, medial capsular reefing, and medial displacement of the infrapatellar tendon insertion. The procedures was originally described by Roux and later modified and popularized by Elmslie and Trillat. It allows adequate evaluation and easy adjustment of the extensor mechanism at the time of surgery. This current report is an evaluation of 116 of these procedures followed for at least one year and examined by an orthopaedic surgeon. This evaluation indicates that this is a satisfactory method for prevention of recurrent subluxation of the patella with recurrence in only 7% of the cases. A critical evaluation of the results of the procedure reveals only 66% were rated as good or excellent. The results were directly related to associated intraarticular pathology such as hemarthrosis, patellar chondromalacia, degenerative changes on the femoral or tibial articular surfaces, torn or absent semilunar cartilages, torn anterior cruciate ligaments, and insufficient correction of either patella alta or a wide quadriceps angle. The procedure has been slightly modified and the indications for the procedure have been revised.

Adolescent↗
PubMed1995

The effect of knee flexion and quadriceps contraction on the axial view of the patella.

Axial views of the patella are standard in the investigation of anterior knee symptoms, and many investigators use congruence angles and patellar tilt in determining the diagnosis and appropriate treatment. A variety of different methods are used to obtain axial radiographs of the patella, but they are static representations of a dynamic phenomenon. The effect of quadriceps contraction on these indices has not been well defined. The purpose of this study was to compare the 30 degree axial view of the patella with the 45 degree axial view of the patella and to study the effect of quadriceps contraction on the 30 degree axial radiograph of the patella. Forty knees with normal patellofemoral joints and 20 knees with patellar subluxation were radiographed using 30 degree axial views of the patella with the quadriceps relaxed and contracted and with 45 degree axial views with the quadriceps relaxed. There was no significant difference in the sulcus or congruence angles between the 30 and 45 degree axial view in either the control or the patellar subluxation group. Contraction of the quadriceps did not cause a significant or consistent alteration in the congruence angles in either group. With quadriceps contraction, 55% of patients will centralize the patella, whereas 40% will actually increase lateral tracking or subluxation. In conclusion, the 30 degree axial view of the patella is equivalent to the 45 degree axial view in the assessment of patellar subluxation. Quadriceps contraction does not alter the congruence angles obtained in these axial views in a significant or consistent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

The diagnosis and treatment of medial subluxation of the patella after lateral retinacular release.

Five patients with medial subluxation of the patella occurring after isolated lateral retinacular release were treated between July 1985 and July 1989. The diagnosis was made by clinical examination. The patients complained of pain, swelling, and giving way after the lateral release. All five patients had increased medial passive patellar mobility, a positive gravity subluxation test, and a positive medial apprehension test. All patients failed conservative treatment. The patients were treated by reconstruction of the lateral retinaculum using sensory epidural anesthesia. At an average followup of 3.3 years, four of the five patients had no symptoms of instability and the medial patellar mobility and gravity subluxation tests were negative. There were three excellent and two good results using the grading system of Merchant and Mercer.

Adult↗