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Treatment options for chondral and osteochondral defects of the patella have been few and results have been inconsistent at best. Autologous osteochondral transplantation presents a new way to revisit these patellar defects. We report the case of a young female softball player with a simple cyst in the patella and an osteochondral defect that serves as the indication for autograft osteochondral transplantation.
Paget's disease is a common skeletal disorder in the elderly; however, monostotic Paget's disease of the patella is very rare and only a few cases have been reported. We present the clinical, radiographic, surgical and histological findings in a patient with monostotic Paget's disease of the patella, presenting with knee pain.
This study uses metrical characteristics of the patella to derive population specific equations for sex determination in South Africa. Six measurements were taken from 120 normal and undamaged left patellae in a sample of known race, equally distributed by sex, obtained from the Raymond A Dart collection of human skeletons. These data were subjected to discriminant analysis. Maximum height and maximum breadth were selected in the stepwise analysis with an average accuracy of 83% in correct sex classification. Four functions were derived from the direct analysis with a range of average accuracy between 77% and 85%. While most individual variables showed high misclassification rates and may not be useful on their own, maximum height and maximum breadth have an average accuracy of 85 and 79%, respectively.
To prevent patella infera in open wedge high tibial osteotomy, a new operation technique was developed. Instead of a proximal tibial tuberosity osteotomy, a distal osteotomy was performed and the tuberosity was fixed with one screw to the tibia. Initial experience in 17 patients was evaluated and compared with results of 20 patients with open wedge high tibial osteotomy with proximal tuberosity osteotomy. Distal tuberosity osteotomy in open wedge high tibial osteotomy appears effective in preventing patella infera.
In revision total knee arthroplasty (TKA), control of the patellar height and the joint line is difficult. Therefore, we developed an adjustable flexion-extension spacer, the Knee Joint-line Balancer (KJB(R)). This device simulates femur component sizes, polyethylene sizes, the joint-line level, and distal femur wedges. The goal of this study is to evaluate the use of an adjustable knee spacer to control patellar height and joint-line during revision total knee surgery. The subjects of the study were the first 10 consecutive patients who had undergone revision of a primary TKA where the KJB was used. A reference group composed of the last 10 patients treated without the use of the KJB was also evaluated. The joint-line position and the patellar height were determined before and after revision TKA. The method described by Figgie et al. was used. The patellar height in the reference group averaged 7.7 mm. Seven of 10 patients had a patella baja, and two of these patients had patellar impingement. One patient needed a proximalisation of the tuberositas. The patellar height in the KJB group averaged 14.6 mm after revision, with only one patient having a patella baja. This new device, adjustable kneespacer for revision TKA ("the KJB"), seems to provide better control of the patellar position in total knee revision.
This study aims to demonstrate that postoperative immobilisation in a cast is unnecessary following suture repair of the patella tendon and retinacula protected by a cerlage wire. We present 11 patients mean age 42 years evaluated at a mean of 26 months (range 14-38 months). The mean Lysholm knee score at review was 97 (range 92-100). The mean Insall Salvati measurement (length patella/length tendon (LP/LT)) was 1 (range 0.95-1.1). No patients had fixed flexion deformities or demonstrated an extensor lag and the average range of motion was 0-137 degrees. The difference between the operated and control knee at the time of assessment was: a mean loss of power of 6% (range 2-11) when measuring concentric extension and a mean loss of 7% power (range 13 to an increase of 12) in concentric flexion. We conclude that primary repair protected with a cerlage wire and early mobilisation gives excellent results in the treatment of isolated traumatic patella tendon ruptures and cast immobilisation postoperatively is not required.
Glomerular lesions typical of the nail-patella syndrome were found in the renal biopsy of a patient with microscopic hematuria. Extensive clinical and radiologic examinations failed to reveal skeletal or other abnormalities characteristic of this syndrome. The possibility that the typical ultrastructural changes of the nail patella syndrome may be present in other renal diseases must be considered.
We reviewed 41 knees at a mean of 4 years after arthroscopic lateral release of the extensor mechanism. The operations were performed for recurrent complete dislocation, not for subluxation, maltracking, or lateral pressure syndrome. Thirty-three of these knees were reviewed again 8 years after operation. There were 39% excellent results according to the criteria of Crosby and Insall at 4 years and 30% at 8 years. Patellar stability improved between 4 and 8 years (p < 0.01). The results in patients with subluxation of the patella on extension of the knee or generalized ligament laxity were poor; five of seven patients with these conditions were worse and had undergone another operation. With these conditions excluded, the excellent results decreased from 50% after 4 years to 37% after 8 years. The results of lateral release are better than those reported after other procedures. It is concluded that arthroscopic lateral release is the procedure of choice for patients with recurrent complete dislocation of the patella unless there is abnormal ligament laxity or subluxation on extension. The operation should not be performed in the presence of these conditions.
We present a case of bilateral osteonecrosis of the patella in a patient during steroid therapy and demonstrate the radiological, arthroscopic, and histological features. Osteonecrosis of the patella should be considered as a possible cause of knee pain in patients receiving steroid therapy.
Osteochondritis dissecans of the patella is a relatively rare condition. Surgical treatment has been recommended for those patients who fail conservative treatment, or who present with mechanical symptoms or loose bodies. In an attempt to preserve the patellofemoral articulation, we describe a new technique to arthroscopically fix osteochondritic lesions of the patella using bioabsorbable pins. This technique avoids the morbidity of a formal arthrotomy as well as the complications associated with metallic hardware.
The development of a resection guide that facilitates accurate preparation of the patella during total knee arthroplasty is reported. Use of the guide prevents tilting of the prosthesis, as well as over or underresection of the patella.
Patellofemoral problems occur in approximately 5% of total knee arthroplasties and account for 50% of complications of total knee arthroplasty. Surgical disruption of the blood supply to the patella may cause an increase in the incidence of osteonecrosis, stress fracture, and loosening. The authors discuss patellar blood supply and surgical considerations in total knee arthroplasty and review the clinical experience with avascular patellae.
Bone hardness of 10 human patellas in 15 regions and at three depths was measured through in situ indentation tests. Indentation tests were performed perpendicular to the three articular surfaces (lateral and medial facets, and central ridge area) and, thus, parallel to the trabeculae. Multiple regression analysis demonstrated a significant reduction of bone hardness with depth. In addition, the lateral facet had a higher bone hardness than the medial facet, and the proximal and central regions demonstrated higher bone hardness than the distal region. Overall, the proximolateral region of the patella exhibited the highest hardness compared with other regions. As bone hardness is indicative of load bearing, these results may have important consequences for patellar resurfacing and patellar component design.
Intra-articular dislocation of the patella is a rare clinical condition. Only forty-five cases have been reported. Most of them were encountered in adolescents and required an open reduction. We report two cases in an older age group with an incomplete rotation of the patella, which were successfully treated by closed reduction. We discuss the literature and suggest that the management depends on the degree of patellar rotation.
We measured the stiffness of the cartilage of the human femoral condyles via an ultrasonic tactile sensor under arthroscopic control. The stiffness and the degeneration of articular cartilage were assessed in 105 knees in 74 patients (39 men, 35 women, age: 9-72 years) who underwent arthroscopic observation or surgery. Twenty-five knees suffered from traumatic cartilage injury, 14 from osteochondritis dissecans, 13 from osteoarthritis, 11 from meniscal injury and six from ligamentous injury, bipartita patellae (three knees), and symptomatic plica synovialis (two knees). The degeneration of cartilage was classified according to Outerbridge's grading system. The relationships between the stiffness and the grade of cartilage degeneration, and gender were analyzed. The stiffness of grade I (softening) and II (fissuring less than 0.5 inches in length) was significantly lower than that of intact cartilage. In contrast, the stiffness of grade IV (exposed subchondral bone) was significantly higher than that of any other group. The cartilage stiffness of the patella in women was significantly lower than that in men. The tactile sensor was useful for determining the intraoperative stiffness of healthy and diseased human cartilage in all grades.
The LIM-homeodomain protein Lmx1b plays a central role in dorso-ventral patterning of the vertebrate limb. Targeted disruption of Lmx1b results in skeletal defects including hypoplastic nails, absent patellae and a unique form of renal dysplasia (see accompanying manuscript by H. Chen et al.; ref. 2). These features are reminiscent of the dominantly inherited skeletal malformation nail patella syndrome (NPS). We show that LMX1B maps to the NPS locus and that three independent NPS patients carry de novo heterozygous mutations in this gene. Functional studies show that one of these mutations disrupts sequence-specific DNA binding, while the other two mutations result in premature termination of translation. These data demonstrate a unique role for LMX1B in renal development and in patterning of the skeletal system, and suggest that alteration of Lmx1b/LMX1B function in mice and humans results in similar phenotypes. Furthermore, we provide evidence for the first described mutations in a LIM-homeodomain protein which account for an inherited form of abnormal skeletal patterning and renal failure.
Dorsal-ventral limb patterning in vertebrates is thought to be controlled by the LIM-homeodomain protein Lmx1b which is expressed in a spatially and temporally restricted manner along the dorsal-ventral limb axis. Here we describe the phenotype resulting from targeted disruption of Lmx1b. Our results demonstrate that Lmx1b is essential for the specification of dorsal limb fates at both the zeugopodal and autopodal level with prominent phenotypes including an absence of nails and patellae. These features are similar to those present in a dominantly inherited human condition called nail patella syndrome (NPS), which also has renal involvement. Mouse Lmx1b maps to a region syntenic to that of the NPS gene, and kidneys of Lmx1b mutant mice exhibit pathological changes similar to that observed in NPS (refs 5,6). Our results demonstrate an essential function for Lmx1b in mouse limb and kidney development and suggest that NPS might result from mutations in the human LMX1B gene.
The central one-third bone-patella tendon-bone graft is a popular choice for arthroscopic anterior cruciate ligament reconstruction. Complications following graft harvesting are unusual, but several reports have been published. We report an unusual case involving a simultaneous patella fracture and patellar tendon rupture that occurred 6 weeks postoperatively.