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PubMed2005

Structural properties of reconstruction constructs for the interosseous ligament of the forearm.

PURPOSE: The Essex-Lopresti fracture-dislocation, also termed longitudinal radioulnar dissociation (LRUD), results in major functional impairment from pain and limitation of motion at the wrist and elbow. Interosseous ligament (IOL) reconstruction has been proposed to help treat LRUD and restore forearm stability. The objective of this study was to evaluate the biomechanical structural properties of 3 different IOL reconstruction constructs and of the intact IOL for comparison. METHODS: Structural tensile testing was performed on 24 fresh-frozen cadaveric forearms with 4 different forearm conditions: IOL intact and IOL reconstructed with Achilles tendon, flexor carpi radialis (FCR) tendon, and bone-patellar tendon-bone. Isolated radius-IOL-ulna constructs were loaded to failure in a materials testing machine with force applied along the local fiber direction. RESULTS: Stiffness in the intact IOL was 129 +/- 31 N/mm, which was significantly stiffer than any of the constructs tested. The intact IOL was 8 times stiffer than the Achilles tendon construct, 7 times stiffer than the FCR construct, and 3 times stiffer than the bone-patellar tendon-bone construct. The Achilles tendon and FCR constructs were similar to each other biomechanically but the bone-patellar tendon-bone construct was slightly stiffer than the Achilles tendon and FCR constructs. CONCLUSIONS: All graft constructs tested were inferior structurally to the intact IOL. The results of this study provide a biomechanical basis for graft selection for reconstruction of the IOL.

Aged↗
PubMed1980

Hinged total knee arthroplasty.

Analysis of an on-going prospective study of seventy-seven hinged total knee arthroplasties in sixty-seven patients revealed that most patients had improvement in function, although major complications occurred in eighteen knees (23.4 per cent. These complications included sepsis, loosening, patellar tendon rupture, peroneal palsy, and patellar subluxation. Eight of nine knees with deep sepsis required removal of the prosthesis, and three of sixteen knees with patellar pain required realignment of the quadriceps. When prosthetic failure occurred, salvage of a functional extremity was difficult. Hinged total arthroplasty is not without its problems, and a cautious approach to its use is indicated. Whenever possible, a moderately constrained replacement arthroplasty should be considered.

Adult↗
PubMed1993

Patellar tilt and subluxation in total knee arthroplasty. Relationship to pain, fixation, and design.

Two hundred thirty-four primary total knee prostheses were evaluated with a 45 degrees merchant view to examine patellar position and fixation. Despite a standardized technique for obtaining roentgenographs, patellar position varied with leg position. Overall, 54.7% tracked centrally, 31.2% tilted, and 14.5% displaced. The incidence of these findings was the same whether the patella was domed or congruent. Neither pain scores nor fixation were affected by position. Postoperative tilt and displacement were more common in patellae that were tilted preoperatively. The incidence of postoperative tilt or displacement was not significantly different in knees in which a lateral release was performed. Patellar tilt in some patients seems inevitable despite careful technique because intraoperative tests are static and postoperative function is dynamic. This does not bode well for wear in a metal-backed patella. Tilt caused increased loading at the periphery of the component where most metal-backed prostheses have thin polyethylene.

Aged↗
PubMed1988

CT-scan in the diagnosis of patellar malalignment.

Fifty-one knees with patellofemoral symptoms, but with normal conventional radiographs, were studied by CT-scan. All but five showed evidence of malalignment, and when operated on had an abnormality of the articular cartilage. The authors conclude that in many cases a CT-scan is the best diagnostic procedure for the evaluation of disorders of the patellofemoral joint.

Adolescent↗
PubMedDate not supplied

[Patellar malposition, its incidence in patellar chondropathy and in a control population].

Patellar disequilibrium consists of either external malpositioning of the patella (EMP) or external hyperpression (EHP), which are clearly visible on a 30degrees axial radiograph of the knee. Does this disequilibrium play a role in the development of patellar chondropathy? The authors have based their comparisons on a series of 40 subjects more than 60 years of age (average age: 68 years) who were free from pain and arthrosis of the knee. In this group they found 2 cases of EMP (5 percent) and 3 of EHP (7.5 percent). In their series of cases of patellar chondropathy (43 cases) there were, after correction for the cases with a double etiology, 8.5 cases of EMP (20 percent) and 7 of EHP (16 percent). The differences between these figures and those for the control series are statistically significant for the number of cases of EMP (P less than 0.05), but not for the number of cases of EHP, the etiological role of which is probable but for which proof would require a larger series of patients. From this work the following findings emerge: (1) The frequency of latent patellofemoral arthrosis in the aged control subjects with knee problems. 7 cases out of 47, or 12.5 percent. (2) The frequency of patellar chondropathy apparently associated with the two etiological factors: out of 43 patients, 22 suffered from patellar disequilibrium (10 EMP and 12 EHP) but in 13 cases there was another associated possible cause of deterioration: traumatism or stress on the knee associated with work or sport. This methodological difficulty is discussed and resolved empirically. The importance of patellar disequilibrium in the development of degenerative patellofemoral affections derives not from the etiological importance but from the fact that they represent the only factor for which therapy may be given: elective internal rehabilitation or surgery (section of the external wing of the patella or transposition of the anterior tuberosity of the tibia).

Aged↗
PubMedDate not supplied

Primary stability with tibial press-fit fixation of patellar ligament graft: An experimental study in ovine knees.

PURPOSE: To investigate the initial fixation strength and to assess the value of tibial press-fit fixation of the bone-tendon-bone graft in anterior cruciate ligament reconstruction. TYPE OF STUDY: Nonrandomized control trial. METHODS: For tibial press-fit fixation, the tibial bone block of the bone-tendon-bone graft is countersunk in a bony groove at the distal tunnel outlet and fixed over a bone bridge with 2 No. 6 Ethibond sutures. The bone cylinder harvested from the tibial tunnel using an oscillating hollow saw is plugged into the tibial tunnel parallel to the graft, thus providing for additional anchoring of the graft by tibial press-fit fixation. In a comparative experimental study in 46 ovine knees, this fixation method was assessed for its value in anterior cruciate ligament reconstruction. A tibial bone tunnel was placed in routine manner in each ovine tibia using a target drill unit and an oscillating hollow saw. The complete patellar ligament, proximally attached to the patella and distally to a cylindrical bone block (20 x 8.4 mm), served as graft. Tibial fixation in group A (n = 10) was done using a titanium interference screw (20 x 8 mm), in group B (n = 10) using a titanium staple, in group C (n = 12) using suture fixation over a bone bridge, and in group D (n = 14) using the press-fit fixation described above. In a materials testing machine, all specimens were subjected to continuously increasing load until failure at a velocity of 1 mm/second. Ultimate failure load, stiffness, stress-strain characteristics, and failure mode were evaluated. RESULTS: Ultimate load to failure was 572 N (range, 473 to 680 N) in group A, corresponding to a fixation stiffness of 17.68 N/mm. For group B, ultimate load to failure was 608.4 N (range, 511 to 727 N) and stiffness of 19.92 N/mm. Bone block dislocation was the failure mode in groups A and B. Group C with exclusive suture fixation showed an ultimate load to failure of 304.5 N (range, 120 to 327 N) and a stiffness of only 6.96 N/mm. The mode of failure was suture cutout caused by the bone block in 9 of the cases and untying of the suture knot in 3 cases. Group D with press-fit fixation showed a significantly higher primary stability of 758 N (range, 513 to 993 N) relative to group C, with a corresponding stiffness of 25.12 N/mm (P <.02). In this group, the mode of failure was ligamentous rupture from the bone block. Regarding mechanical properties, no significant differences were seen between groups A, B, and D. CONCLUSIONS: Tibial press-fit fixation allows for metal-free fixation with high primary stability. By refilling the bone tunnel, the ligament (with a rather small cross-sectional diameter compared with hamstrings) is safely fixed within the bone tunnel to prevent potential postoperative tunnel enlargement due to movement of the graft within the tunnel. Anchoring the graft at the entrance into the joint, it provides for reduced graft length and adequate elasticity and accomplishes the requirements of fixation at the correct anatomic insertion site.

Animals↗
PubMed1990

[Dysplasia of the femoral trochlea].

Dysplasia of the trochlea was studied on a strict profile image of the knee. 1305 radiographs were analysed corresponding to several patello-femoral conditions (major and subjective patello-femoral osteoarthritis) and to control subjects. Two criteria are defined: the depth and the eminence of the trochlea. The depth was often minimal in instabilities that give a radiological characteristic image of intersection between the trochlear end line and the lateral condyle. This picture had a great diagnostic value for patellar instability. The eminence represented the owerhang of the trochlear end line in relation to the anterior cortex of the femur. By measuring it, it was possible to establish a statistically significant variability of the degree of instability on one hand, between instabilities, patellar syndromes and controles on the other hand. The intersection sign and the trochlear eminence in isolated patello-femoral osteoarthritis allows the direct filiation between dysplasia of the trochlea and osteoarthritis to be confirmed. Taking into account the size of the eminence, the hollowing out type trochleoplasties appears more fiable than raising of the lateral edge.

Bone Diseases, Developmental↗
PubMed2001

[Anterior knee pain associated with sports and work].

Anterior knee pain is not a disease, but a syndrome with numerous causes. This paper describes its appearance in the patellofemoral joint in sportsmen and in untrained people. Chondromalacia patellae is a condition of the cartilage, not a disease, that is, it is never diagnosed alone. Relative muscular insufficiency, especially of the knee extensors, may occur in children and adolescents, as they grow rapidly. The consequence is a unbalance of active stabilizers and the disturbance of the slippery trail of patella, particularly in the presence of dysplasia of patellofemoral joint. The impingement syndrome pain occurs in sportsmen and people overloading the patellofemoral joint. Other causes of anterior knee pain should be excluded in clinical examination and slippery trail of patella, its position, and signs of instability should be determined. This paper gives an overview of patellar chondromalacia, lateral pressure syndrome, patellar subluxation, patellar acute and recurrent luxation, and idiopathic anterior knee pain. The treatment is basically conservative. Stretching exercises and the strengthening of certain groups of femoral muscles serves to regain the balance, thus normalising the slippery trail and taking off the burden from the patellofemoral joint. If conservative treatment fails, surgery is the alternative.

Athletic Injuries↗
PubMed1989

Patellar complications in total knee arthroplasty. A literature review.

Increased implant longevity, improved range of motion, and the use of total knee arthroplasty in younger and more active patients have placed greater demands on the patella component. Commonly observed complications of the patellofemoral joint are crepitation, subluxation, excessive wear, loosening, and persistent patient discomfort. These complications have been attributed to inadequate prosthetic design, fixation techniques, anatomic abnormalities, and surgical error. This paper reviews the most prevalent complications and discusses their causes and prevention.

Biomechanical Phenomena↗
PubMed1982

Patellar complications after total condylar arthroplasty.

The incidence of complications in the initial three years' experience with total knee arthroplasty and patellar replacement was 9%. Of the total knee arthroplasties perforated in the last three years, neither fracture nor subluxation of the patella has occurred. A prosthesis with right and left femoral components and slight lateral (physiologic) slanting of the patellar groove is recommended. Lateral release is done only if absolutely necessary and is performed at a considerable distance from the patella to preserve blood supply. Excess bone removal from the patella is avoided. The fat pad is preserved in all cases. Patients who have undergone a patellectomy had a definitely weak knee. Treatment by simple immobilization failed to produce an excellent functional result.

Aged↗
PubMed1983

Patellar pain and incongruence. I: Measurements of incongruence.

In 150 normal asymptomatic knees, the average Q angle was 15 degrees. The patellar length was equal to the patellar ligament length, and the average congruence angle was -8 degrees. In 53 knees with recurrent subluxation, the patella was high-riding (TP, 1.23), the sulcus angle was shallow (147 degrees), and the average congruence angle was +16 degrees. In 53 knees with "chondromalacia," the Q angle was increased (20 degrees), and the average congruence angle was -2 degrees.

Adolescent↗
PubMed2005

Cemented rotating-platform total knee replacement. a concise follow-up, at a minimum of fifteen years, of a previous report.

We previously evaluated 119 consecutive total knee arthroplasties that were performed in eighty-six patients with use of the cemented LCS (low contact stress) rotating-platform system with an all-polyethylene patellar component. The average age of the patients at the time of surgery was seventy years (range, thirty-seven to eighty-eight years). The purpose of this study was to report the updated results at a minimum follow-up of fifteen years. Thirty-seven patients (fifty-three knees) were living, and no patient was lost to follow-up. No knee was revised because of loosening, osteolysis, or wear. Three knees required a reoperation (two for periprosthetic fractures and one for infection). No component was revised as a part of the reoperations. Osteolysis was present in three knees. No knee had radiographic signs of component loosening, and there were no dislocated bearings. The average range of motion was from 1 degrees of extension to 105 degrees of flexion. The average clinical and functional Knee Society scores were 43 and 49, respectively, at the preoperative evaluation and 85 and 58 at the time of the final follow-up. We concluded that the cemented LCS rotating-platform knee performed well, with durable clinical and radiographic results at a minimum follow-up of fifteen years.

Activities of Daily Living↗
PubMed2006

Vertical patellar position in large-breed dogs with clinically normal stifles and large-breed dogs with medial patellar luxation.

OBJECTIVE: To further define vertical patellar position, as measured by the ratio of patellar ligament length to patellar length (L:P), in large-breed dogs with clinically normal stifles and compare that to the L:P of large-breed dogs with medial patellar luxation (MPL). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Large-breed dogs (n = 50) with clinically normal stifle joints and 30 large-breed dogs with MPL. METHODS: Large-breed dogs with clinically normal stifle joints or MPL were identified and divided into groups (NORM and MPL, respectively). L:P values were determined for each dog by 4 observers from single lateral stifle radiographs. L:P was compared between NORM and MPL groups and 95% confidence intervals (CIs) were calculated. RESULTS: All 4 observers found a significantly higher L:P (more proximally positioned patella) for the MPL group compared with the NORM group. Overall mean (+/-SEM) L:P were: NORM, 1.71+/-0.020 and MPL, 1.87+/-0.025. The 95% CI was determined to be 1.45-1.97 for the NORM group and 1.57-2.17 for the MPL group. CONCLUSIONS: Large-breed dogs with MPL had a significantly more proximal vertical patellar position compared with large-breed dogs with clinically normal stifles. Large-breed dogs with L:P values >1.97 are considered to have patella alta. CLINICAL RELEVANCE: Proximal displacement of the patella within the femoral trochlear groove may play a role in MPL in large-breed dogs.

Analysis of Variance↗
PubMed1993

Congenital abnormalities in immature dogs from a pet store: 253 cases (1987-1988).

In a pet store, 6- to 18-week-old dogs were examined for congenital abnormalities. Of those pups offered for sale over a 2-year period (1987 and 1988), 15% (253/1,679) had at least 1 congenital defect, and 1.5% (26/1,679) had multiple congenital abnormalities. Defects observed and their respective rates were patellar luxation, 7.2% (121/1,679); cardiac abnormalities characterized by murmurs, 0.7% (11/1,679); palpebral abnormalities, 3.0% (50/1,679); inguinal hernia, 1.3% (22/1,679); umbilical hernia, 0.6% (10/1,679); faciodental malformations, 1.3% (21/1,679); and cryptorchidism, 2.6% (44/1,679). Rates of congenital abnormalities in pups from this study were higher than published rates in adult dogs.

Animals↗
PubMed1979

Chondromalacia and recurrent subluxation of the patella: a study of malalignment, with some indications for radiography.

The authors adopted four parameters in a study of 100 normal subjects and fifty patients affected by "chondromalacia" or by recurrent subluxation of the patella. These were: the quadriceps angle, the ratio between the length of the patellar tendon and the length of the patella, the femoral sulcus angle, and the congruence angle between the femur and patella. These parameters showed a statistically significant increase in the pathological group, thereby demonstrating that the majority of cases of "chondromalacia" of the patella and those of recurrent subluxation constitute two entities forming part of the same disease, the basis of which is malalignment and malposition of the patella.

Adolescent↗
PubMed1986

The patellofemoral joint in total condylar knee arthroplasty. Pros and cons based on five- to ten-year follow-up observations.

In this report, 100 knees in 77 patients, with an average age of 65, were followed for a period between five and 10 years. Rheumatoid arthritis was the diagnosis in 43 patients and osteoarthritis in 34 patients. The majority had varus, valgus, and biplane deformities. Twenty-one patients underwent bilateral procedures; all but one had patellar replacement. Over 90% of the knees were rated good to excellent according to The Hospital for Special Surgery Knee Disability Score Sheet. Of the 34 osteoarthritic patients (40 knees), 24 or 71% could walk ten blocks and beyond. Ten patients, or 29%, could walk between one and ten blocks. Further ambulation was restricted only by overall poor health and age (most were 74 years of age or older). Twenty-four patients, or 71%, could ascend and descend stairs without support, while six (18%) relied on bannister support when descending stairs. Four patients (11%) required bannister support for both ascending and descending stairs. Among the complications seen in this series were one loose patella and another with osteonecrosis of the anterior surface. No dislocations occurred, but 14 patellae showed tilt on skyline view roentgenograms, indicating a tight lateral retinaculum. In view of the good to excellent results achieved in the majority of patients, and the low morbidity associated with replacement, it is recommended that the patellofemoral joint be replaced in the course of total knee arthroplasty. When careful attention is paid to technical details, this procedure improves the quality of the arthroplasty.

Adult↗
PubMed1987

Investigation into the heredity of congenital lateral patellar (sub)luxation in the Shetland pony.

A breeding experiment was carried out in a group of Shetland ponies in order to investigate the heredity of congenital lateral patellar (sub)luxation. A breeding herd was established and consisted of stallions and mares acquired at different times. Some were free from, and others were affected by lateral patellar (sub)luxation in either one or both femoropatellar joints. Over a period of 20 years, 49 foals were born from different mating combinations. Some offspring were free from the defect and others showed the abnormality. Though the number of foals bred during the experiment is rather small, there is sufficient evidence to suggest a monogenic autosomal recessive hereditary transmission of the defect.

Animals↗
PubMed2006

Two-strand posterior cruciate ligament reconstruction with a quadriceps tendon-patellar bone autograft: technical considerations and clinical results.

In patients with complete posterior cruciate ligament (PCL) ruptures in which 10 mm or more of increased posterior tibial translation is detected, associated knee disorders must be treated at the same time as the PCL injury. Varus malalignment and any abnormal medial or lateral ligament deficiency must be corrected before or with PCL reconstruction to avoid the risk of failure of the PCL graft. Gait retraining is recommended for patients with abnormal knee hyperextension patterns before ligament reconstruction is performed. Advances in PCL reconstruction include the use of a two-strand graft that may be placed using either a tibial inlay or an all-arthroscopic tibial tunnel technique. Biomechanical studies have shown a reduction in graft tension and improved load sharing in these constructs compared with single-strand reconstructions. The tibial inlay method can be used in athletic patients, and it also is required in PCL revisions in which a prior tibial tunnel must be avoided to achieve graft fixation. The tibial tunnel technique is used to treat dislocated knees for which reconstruction of multiple knee ligaments is required or when prior arterial injury or posterior skin or muscle damage limits the indications for a posterior open approach. Postoperative rehabilitation should protect the PCL graft from high forces and repetitive cyclic knee motions during the first 4 weeks postoperatively.

Humans↗