Meniscal repair. Where do we go from here?

In summary, it has been the task of this article to try to forecast the future of meniscal surgery over the next decade. As we enter the twenty-first century, it becomes evident that a combination approach will be the most likely procedure. The code phrase will be, "Save as much meniscus as possible." The authors predict that accomplishing this objective will involve the use of adhesive materials, possibly autologous but more probably exogenous, supported by the insertion of a collagenous type material, which will serve as a scaffolding for the ingrowth of fibrocartilage, and the healing will be stimulated by hormonal methods. Whether this occurs through recombinant DNA techniques or better methods of precipitation remains an issue. Dose-specific mitogens and chemotactic agents will be placed in the area of injury to potentiate the vascular fibrous response of the host tissue. With earlier and more exuberant fibrous response and initial tissue adhesion from the fibrin adhesive, better stability will be established to allow for primary healing of meniscal tissues. This procedure will work well for longitudinal tears of the meniscus. A dilemma arises with more complex tears of the meniscus, however. Previously irreparable tears may be conducive to resection then replacement with cultured autologous fibrochondrocytes, either in a gel-type form or on scaffolds made of collagen or biodegradable materials. These scaffold/fibrochondrocyte replacements may be contoured to the defect present and bonded tightly with the fibrin adhesives previously discussed. Again, growth factors would be needed for ultimate success as the fibrochondrocytes mature into the appropriate morphologic subpopulations and begin to turn over their own extracellular matrix. The patient would have a neomeniscal autologous transplant with normal host cell turnover of matrix. A brave new era lies ahead for meniscal repair, and the journey promises to be a most exciting one.

Critical analysis of knee ligament rating systems

Sixty-five patients who consecutively underwent anterior cruciate ligament reconstruction were studied using four individual, categoric, knee score rating systems. Different results were noted at followup (mean, 35 months; range, 24 to 58) depending on the rating method used. Ali patients were graded using the Hospital for Special Surgery, Lysholm, Tegner activity, and Cincinnati Knee Ligament rating systems. The Cincinnati Knee Ligament rating individual scores were noted to be lower than the Hospital for Special Surgery and Lysholm scores for subjective and objective outcome assessment. The Hospital for Special Surgery and Lysholm scores did not correlate highly with the Cincinnati Knee Ligament rating final rating, but they did correlate with each other. The use of ligament rating scores tended to inflate results, particularly when raw scores were converted to overall categoric ratings (e.g., excellent, good). The Cincinnati Knee Ligament rating system correlates more highly with individual grading and most precisely defines outcome in athletically active patients. Sources of error may be introduced by a disproportionate combination of unrelated scores or by overrating low-activity-level individuals who avoid stressing their knees. Avoidance of data generalization remains the optimal method for studying anterior cruciate ligament surgery outcome.

Paramyxovirus infection in lung transplant recipients

BACKGROUND

Respiratory infections are common after lung transplantation. The significance of respiratory paramyxoviruses, respiratory syncytial virus, and parainfluenza virus in lung transplant recipients has not been determined.

METHODS

In a retrospective fashion, we examined the incidence and clinical characteristics of paramyxovirus infection in 84 consecutive lung transplant recipients at the University of Minnesota Hospital and Clinics from 1986 through 1993.

RESULTS

We identified 19 cases of paramyxovirus infection in 18 patients (21% of all transplant recipients). All patients had symptoms with lower respiratory tract involvement, and nine (47%) had coexisting upper respiratory involvement. Symptom onset was 24 to 2056 days after transplantation (median = 260 days). Respiratory syncytial virus infection was seasonal (January through June), but parainfluenza virus infection occurred throughout the year. Six patients showed a decline in spirometry (26% +/- 2.8% decrease in forced expiratory volume in 1 second); four returned to baseline. Diagnosis was made by bronchoalveolar lavage in 15 cases, nasopharyngeal swab in three cases, and sputum in one case. Most patients (74%) were treated with ribavirin, and all but one treated patient recovered fully. In untreated patients, respiratory syncytial virus contributed to one death and one parainfluenza virus infection resulted in a persistent reduction in spirometry. Age was the strongest predictor of infection, with a higher incidence in patients under 18 years old (57%, p < 0.05). Preexisting obliterative bronchiolitis did not correlate with an increased incidence of paramyxovirus infection (20% with obliterative bronchiolitis, 22% without obliterative bronchiolitis; p > 0.05).

CONCLUSIONS

Lower respiratory tract infection with paramyxovirus is common in lung transplant recipients and capable of causing death or a permanent reduction in pulmonary function.

In vitro assembly of cowpea chlorotic mottle virus from coat protein expressed in Escherichia coli and in vitro-transcribed viral cDNA

The small spherical plant virus, cowpea chlorotic mottle virus (CCMV), provides an ideal system to examine spherical virus assembly. We have modified the CCMV in vitro assembly system to produce virions from coat protein expressed in Escherichia coli and viral RNA transcribed in vitro from full-length cDNAs. Examination of the in vitro-assembled particles with cryoelectron microscopy and image reconstruction techniques demonstrates that the particles are indistinguishable from plant purified particles at 2.5 nm resolution. Mutational analysis of the coat protein N- and C-terminal extensions demonstrate their respective roles in virus assembly. The N-terminus is required for assembly of RNA containing particles but not for the assembly of empty virions. The C-terminus is essential for coat protein dimer formation and particle assembly.

Malignant pleural effusion

Pleural effusion is a frequent complication of malignant disease. With a realization of pathophysiological mechanisms, symptomatology, and specific care needs of patients, the nurse can make appropriate assessments and provide thorough and essential care to improve patient outcome.

Thermoregulation in Yersinia enterocolitica is coincident with changes in DNA supercoiling

Yersinia enterocolitica is a facultative intracellular parasite, displaying the ability to grow saprophytically or invade and persist intracellularly in the mammalian reticuloendothelial system. The transition between such diverse environments requires the co-ordinated regulation of specific sets of genes on both the chromosome and virulence plasmid. Temperature has a profound pleiotropic effect on gene expression and phenotypically promotes alterations in cell morphology, outer-membrane protein synthesis, urease production, lipopolysaccharide synthesis, motility, and synthesis of genes involved in invasion of eukaryotic host cells. By examining thermoregulated flagella biosynthesis, we have determined that motility is repressed at 25 degrees C (permissive temperature) with subinhibitory concentrations of novobiocin. These conditions also induce virulence gene expression suggesting novobiocin addition simulates, at least partially, a high-temperature environment. Furthermore, temperature-shift experiments, using Y. enterocolitica containing pACYC184 as a reporter plasmid, indicate that thermo-induced alterations of DNA supercoiling coincide with temperature-induced phenotypic changes. A class of putative DNA gyrase mutant (novobiocin resistant) likewise demonstrates the 37 degrees C phenotype when cultured at 25 degrees C; it is non-motile, urease negative, calcium growth dependent, and positive for Yop expression. These results support a model implicating DNA topology as a contributing factor of Y. enterocolitica thermoregulation.

MR diagnosis of recurrent tears in the knee: value of intraarticular contrast material

OBJECTIVE

After surgical resection or repair of a torn meniscus, the healed area may have areas of abnormal signal intensity on MR images. Consequently, routine MR imaging is not reliable for detecting recurrent meniscal tears. As a result, we studied the efficacy of MR imaging with intraarticular contrast material (MR arthrography) for detecting recurrent tears of the meniscus.

SUBJECTS AND METHODS

Thirty-seven patients who previously had a meniscal tear treated by either meniscal resection or repair had conventional MR imaging and MR arthrography with 40-50 ml of a 1:100 solution of gadopentetate dimeglumine in saline. All patients had arthroscopy shortly after the MR studies. Follow-up arthroscopic surgery was performed within an average of 6.6 weeks after the MR arthrograms. The routine MR images and MR arthrograms were reviewed separately and randomly, and these results were compared with the arthroscopic findings. Meniscal morphology, signal intensity, and the presence of joint fluid tracking into recurrent tears were evaluated.

RESULTS

The overall accuracy in diagnosing recurrent meniscal tears in the post-operative meniscus was 66% when conventional MR imaging was used and 88% when MR arthrography was used. In patients who had only minimal meniscal resection, both methods had an accuracy of 89%. In patients who had more extensive meniscal resection, accuracy was 65% with conventional MR imaging and 87% with MR arthrography. In four patients who had only a small meniscal remnant, the accuracy was 50% with routine MR imaging and 100% with MR arthrography. On conventional MR images, the presence of an effusion tracking into a meniscal tear had a sensitivity and positive predictive value of 90% for detection of recurrent meniscal tears; however, the sensitivity was only 41%.

CONCLUSION

Our results show that the sensitivity of MR imaging in detecting meniscal tears after surgery varies with the extent of the resection. Sensitivity was considerably improved when intraarticular contrast material was used. MR arthrography should be considered as an alternative to arthroscopy in patients who have had resection or repair of the meniscus.

Trephination of incomplete meniscal tears

The meniscus performs several roles that are important to the function of the knee joint. In an effort to preserve these functions of the meniscus, methods to promote the healing of meniscal lesions have been investigated. One such method involves trephination or the creation of vascular access channels by removal of a core of tissue from the periphery of the meniscus to the tear, thus connecting a lesion in the avascular portion of the meniscus to the peripheral blood supply. The purpose of this study is to describe our experience with arthroscopic trephination of symptomatic incomplete meniscal tears in humans. This is a simple technique that avoids the risk associated with suture repair of the meniscal tissue, yet preserves the meniscus. Overall results were good or excellent in 90% of the cases. In conclusion, symptomatic incomplete meniscal tears can be treated by stimulation of vascular channels without the risk associated with suturing of this tissue, while preserving the important functions of the meniscus.

Overuse injuries of the knee in basketball

Overuse injuries of the knee are abundant in basketball players. This article discusses the pathophysiology of overuse and the principles of treatment. The diagnosis and clinical management of jumper's knee, patellofemoral pain, and stress fractures are outlined with specific attention to rehabilitation techniques and training.

Arthroscopically assisted anterior cruciate ligament reconstruction with the pes anserine tendons. Comparison of results in acute and chronic ligament deficiency

Fifty anterior cruciate ligament-deficient knees treated consecutively with arthroscopically assisted reconstruction using a pes anserine tendon autograft were retrospectively studied. The mean followup was 36.7 months (range, 26 to 58). All patients had reconstruction with a double-stranded graft. The mean injury to surgery interval was 9.6 days in 22 patients (acute group) and 22.5 months in 28 patients (chronic group). Objective outcome, which was noted to be more optimal in the acute group, was better than subjective outcome in either group. Examination revealed 95% of patients treated acutely and 82% of those treated later to have 1+ or less Lachman test result (P < 0.036) and 96% of the acute group and 82% of the chronic group to have an absent pivot shift (P < 0.036). Eighty-eight percent of acutely treated patients had a KT-1000 result of < or = 3 mm, as compared to 61% of chronically treated patients (P < 0.001). Loss of range of motion was significantly greater in the acute group (P < 0.018). Using a strict overall rating system, patients reconstructed earlier were noted to have a better outcome compared to those after delayed reconstruction (P < 0.021). Cumulative meniscal injury appears to be the most significant contributing factor.

Obliterative bronchiolitis after lung transplantation: a fibroproliferative disorder associated with platelet-derived growth factor

Fibroproliferative disorders are characterized by accumulations of mesenchymal cells and connective tissue in critical locations, leading to organ dysfunction. We examined the role of platelet-derived growth factor (PDGF) in the pathogenesis of obliterative bronchiolitis, a fibroproliferative process that occurs after lung transplantation and results in small airway occlusion. Bronchoalveolar lavage fluid from obliterative bronchiolitis patients significantly stimulated fibroblast migration, whereas fluid from patient controls did not. Quantitation by radioligand binding assay demonstrated increased concentrations of PDGF in lavage fluid from obliterative bronchiolitis patients (patients, 104 +/- 26.9 pM; controls, 8.4 +/- 6.9 pM; P < 0.01). Heparin affinity, gel filtration, and Western blot analysis confirmed the presence of PDGF in lavage fluid. Immunohistochemical and in situ hybridization studies of histologic sections and bronchoalveolar lavage cells suggest that alveolar macrophages are one cellular source. Prospective evaluation of sequential bronchoalveolar lavage samples from a patient who developed obliterative bronchiolitis demonstrated markedly increased PDGF concentrations before the onset of irreversible airflow obstruction. These findings are consistent with a role for PDGF in the fibroproliferative changes observed in obliterative bronchiolitis.

Neural responses to visual texture patterns in middle temporal area of the macaque monkey

1. We studied how neurons in the middle temporal visual area (MT) of anesthetized macaque monkeys responded to textured and nontextured visual stimuli. Stimuli contained a central rectangular "figure" that was either uniform in luminance or consisted of an array of oriented line segments. The figure moved at constant velocity in one of four orthogonal directions. The region surrounding the figure was either uniform in luminance or contained a texture array (whose elements were identical or orthogonal in orientation to those of the figure), and it either was stationary or moved along with the figure. 2. A textured figure moving across a stationary textured background ("texture bar" stimulus) often elicited vigorous neural responses, but, on average, the responses to texture bars were significantly smaller than to solid (uniform luminance) bars. 3. Many cells showed direction selectivity that was similar for both texture bars and solid bars. However, on average, the direction selectivity measured when texture bars were used was significantly smaller than that for solid bars, and many cells lost significant direction selectivity altogether. The reduction in direction selectivity for texture bars generally reflected a combination of decreased responsiveness in the preferred direction and increased responsiveness in the null (opposite to preferred) direction. 4. Responses to a texture bar in the absence of a texture background ("texture bar alone") were very similar to the responses to solid bars both in the magnitude of response and in the degree of direction selectivity. Conversely, adding a static texture surround to a moving solid bar reduced direction selectivity on average without a reduction in response magnitude. These results indicate that the static surround is largely responsible for the differences in direction selectivity for texture bars versus solid bars. 5. In the majority of MT cells studied, responses to a moving texture bar were largely independent of whether the elements in the bar were of the same orientation as the background elements or of the orthogonal orientation. Thus, for the class of stimuli we used, orientation contrast does not markedly affect the responses of MT neurons to moving texture patterns. 6. The optimum figure length and the shapes of the length tuning curves determined with the use of solid bars and texture bars differed significantly in most of the cells examined. Thus neurons in MT are not simply selective for a particular figure shape independent of whatever cues are used to delineate the figure.

Single lung transplantation for severe emphysema

Lung transplantation is effective therapy for patients with severe obstructive lung disease. We reviewed seven patients with severe emphysema (age, 48 +/- 5 years; forced expiratory volume in 1 second [FEV1] 0.76 +/- 0.26 liters) who received single-lung transplants (SLT) at our institution between August 1989 and September 1990. Studies to assess the adequacy of cardiac function before transplantation showed moderately reduced right ventricular function (by multiple gated acquisition, 34 +/- 6%), moderately elevated pulmonary artery pressure (25 +/- 3 mm Hg), and normal left ventricular function (by multiple gated acquisition 65% +/- 12%) and coronary arteriograms. Time on the waiting list before transplantation was reduced compared with heart-lung transplant (HLT) recipients (waiting time, 2.9 +/- 1.5 months for SLT, 9.6 +/- 10.2 months for HLT). Six of the SLT recipients are currently alive (after transplantation interval, 17 +/- 5 months); the remaining recipient died of pulmonary embolism 21 days after SLT. Number of ventilator days, intensive care unit days, and days to hospital discharge after transplantation did not differ significantly from HLT recipients. Cardiopulmonary bypass was necessary in four SLT recipients. Pulmonary function was markedly improved after SLT (FEV1, 1.78 +/- 0.73 L/min after SLT versus 0.75 +/- 0.3 L/min before SLT; p less than 0.01), and functional status is correspondingly improved.

CONCLUSIONS

SLT constitutes effective therapy for patients with severe emphysema, including those with moderate reduction of right ventricular function; and SLT offers distinct advantages over HLT, including decreased waiting time before transplantation, improved donor organ utilization, and less frequent need for cardiopulmonary bypass.

Arthroscopic-assisted anterior cruciate ligament reconstruction with the semitendinosus tendon: comparison of results with and without braided polypropylene augmentation

Fifteen chronic anterior cruciate ligament-deficient knees were arthroscopically reconstructed with a semitendinosus tendon polypropylene (STP) augmented composite graft. A comparison group of 28 reconstructions with the semitendinosus tendon (ST) but without augmentation was simultaneously reviewed. The mean follow-up in the STP group was 31 months (range of 24-42 months) and in the ST group it was 34 months (range 26-54 months). Both patient groups had similar age, sex, preinjury functional sports level, injury-to-surgery interval, and associated meniscal pathology. Good-to-excellent subjective results were reported in 86% of STP patients and 78% of ST patients, whereas 86% of the STP patients and 88% of the ST patients returned to sports activity. Objective examination revealed 73% of the STP group and 82% of the ST group to have a negative or 1+ Lachman test result. A negative pivot shift was noted at follow-up in 80% of the STP group and in 82% of the ST group. KT-1000 testing revealed 60% of the STP patients and 61% of the ST patients to have less than or equal to 3 mm of side-to-side difference. In the STP group there was no evidence of graft breakage, deep infections, or sterile effusions. Overall subjective and functional results were uniformly better than objective results in both patient groups. Analysis of subjective, objective, and functional results reveal no difference in outcome between the STP and the ST patient groups.

The postoperative knee

Magnetic resonance (MR) has established itself as the gold standard for noninvasive imaging of the knee. As in arthroscopy, assessment of injuries to the menisci, articular surfaces, synovium, and cruciate ligaments can be made. Additionally, MR has an advantage over arthroscopy in being able to assess the para articular soft tissues and cortical and medullary bony compartments. Until recently, the role of MR in the postoperative knee has been less clear. New information, however, suggests that MR is capable of assessing the status of the partially resected meniscus, the adjacent articular surfaces, and subchondral medullary lesions that frequently occur. There has been recent interest in reestablishment of the stabilizing function of a previously torn anterior cruciate ligament by means of autogenous or allogenous materials. MR permits the surgeon to assess the isometry and possible sites of graft impingement that may occur following cruciate ligament reconstruction. The purpose of this article is to define the current status of MR in the assessment of the postoperative knee.

The anaesthetic management of a patient with a phaeochromocytoma and acute stroke

A case is reported of a young woman in whom the diagnosis of a phaeochromocytoma was made after a major stroke. Preoperative preparation included the introduction of phenoxybenzamine, 10 mg.day-1, and propranolol, 80 mg.day-1, over a two-week period. The presence of cerebrovascular disease and the marked orthostatic changes in blood pressure and heart rate to low-dose phenoxybenzamine prevented the establishment of full alpha blockade. Incomplete alpha blockade probably contributed to the hypertensive response to manipulation of the tumour (220/150 mmHg) and hypotension occurred after removal of the tumour (80/45 mmHg). An anaesthetic technique was chosen to provide haemodynamic stability as well as protection against cerebral ischaemia. Invasive haemodynamic monitoring, a four-channel processed electroencephalograph and somatosensory evoked potentials were used to accomplish these goals.

Osteonecrosis of the knee after arthroscopic surgery: diagnosis with MR imaging

Spontaneous osteonecrosis about the knee typically is a disease of the elderly characterized by an acute onset of pain. The exact cause of this condition has long been debated, although a causative relationship between meniscal tears and spontaneous osteonecrosis about the knee has been postulated. Seven patients with knee pain, meniscal tears, and chondromalacia without initial evidence of osteonecrosis at magnetic resonance (MR) imaging underwent arthroscopic surgery with meniscal recontouring or repair and cartilage shaving. These patients returned within 2-14 months with recurrent pain in the treated knee. MR imaging then demonstrated abnormalities consistent with osteonecrosis. Osteonecrosis of the femoral condyle or tibial plateau may be a late sequela of meniscal injury in association with chondromalacia and arthroscopic surgery. This diagnosis should be suspected in patients with recurrent knee pain after arthroscopic repair of meniscal tears. The precise relationship of this pattern of osteonecrosis to that previously described as spontaneous requires further investigation.

Accuracy of diagnoses from magnetic resonance imaging of the knee. A multi-center analysis of one thousand and fourteen patients

Magnetic resonance images of the knee were made for 1014 patients, and the diagnosis was subsequently confirmed arthroscopically. The accuracy of the diagnoses from the imaging was 89 per cent for the medial meniscus, 88 per cent for the lateral meniscus, 93 per cent for the anterior cruciate ligament, and 99 per cent for the posterior cruciate ligament. The magnetic resonance examinations were done at several centers, and the results varied substantially among centers. The accuracy ranged from 64 to 95 per cent for the medial meniscus, from 83 to 94 per cent for the lateral meniscus, and from 78 to 97 per cent for the anterior cruciate ligament. The results from different magnetic-resonance units were also compared, and the findings suggested increased accuracy for the units that had a stronger magnetic field. Of the menisci for which the magnetic resonance signal was reported to be Grade II (a linear intrameniscal signal not extending to the superior or inferior meniscal surface), 17 per cent were found to be torn at arthroscopy.

Evaluation of patients with persistent symptoms after lateral retinacular release by kinematic magnetic resonance imaging of the patellofemoral joint

The arthroscopic lateral retinacular release is typically performed to treat patellar pain and instability. This procedure was previously considered to be relatively benign with a low associated complication rate. However, a high incidence of medial subluxation of the patella was recently reported in patients with persistent symptoms after lateral retinacular release. Because the use of physical examination criteria may not always be sufficient to assess patellar alignment, 40 patients (43 knees) were evaluated by the newly developed technique of kinematic magnetic resonance imaging of the patellofemoral joint. One (2%) patellofemoral joint had normal patellar alignment, 10 (23%) had lateral subluxation of the patella, 1 (2%) had excessive lateral pressure syndrome, 27 (63%) had medial subluxation of the patella, and 4 (9%) had lateral-to-medial subluxation of the patella. Seventeen of 40 patients (43%) with unilateral arthroscopic lateral retinacular releases had medially subluxated patellae on the unoperated joints. Because patellar malalignment commonly affects bilateral joints, medial subluxation of the patella may have been present before the lateral retinacular release but was not recognized in these patients.

A psychogeriatric nursing assessment protocol for use in multidisciplinary practice

The assessment of geriatric patients with psychiatric or neurobehavioral problems demands a multidisciplinary approach linking nursing, psychiatry, neurology, geriatrics, and internal medicine. While the medical disciplines have relatively well-established approaches to assessing psychogeriatric patients, nursing lacks a comprehensive assessment strategy that supports both nursing and multidisciplinary practice. This article describes the Psychogeriatric Nursing Assessment Protocol (Abraham, 1989) developed for use in a multidisciplinary geriatric neuropsychiatric outpatient clinic. The relationship of the protocol to psychiatric, neurological, geriatric, and medical assessments is discussed in an attempt to clarify the linkages of knowledge and care required for successful service delivery to geriatric patients with psychiatric or neurobehavioral problems, as well as to their families and formal and informal caregivers.

Peripheral meniscal tears: MR findings after conservative treatment or arthroscopic repair

Follow-up knee magnetic resonance (MR) examinations were performed on 17 patients (18 menisci) with arthroscopically proved tears of the outer third of the meniscus who were treated either conservatively (six patients) or with surgical repair (11 patients). All patients satisfied accepted clinical orthopedic criteria for meniscal healing. MR examinations obtained 3-27 months after injury revealed persistent signal intensity (grade 3), unchanged from that seen on the preoperative study, in all 15 patients in whom both pre- and postoperative studies were obtained and in three of four menisci that were proved to be healed at second-look arthroscopy. It appears that grade 3 signal from both conservatively treated and repaired menisci may persist long after the tear has become asymptomatic and has presumably healed. The presence of such signal should not be interpreted as necessarily indicating meniscal retear in these patients. Persistent signal intensity at the site of previous injuries may account for some reported cases of disagreement between MR and arthroscopic findings.

Results of arthroscopic meniscectomy

It would appear that arthroscopic partial menisectomy offers as good, if not better, results compared with open meniscectomy. Authors who have compared patients undergoing open meniscectomy with those undergoing arthroscopic meniscectomy have also shown that the other variables and parameters so important to the patient in the early postoperative period weight very heavily in favor of arthroscopic meniscectomy.

Acute anterior cruciate ligament reconstruction. Analysis of complications

One hundred fifty-six patients treated with intraarticular anterior cruciate ligament (ACL) reconstruction were analyzed to determine the incidence of complications. The study group of 31 patients (Group I) was treated with repair or reconstruction of an acute ACL injury. A comparison group of 125 patients had reconstruction for chronic ACL instability (Group II). The patients were evaluated clinically and by roentgenograms. The average follow-up time for the study group was 52.2 months. In Group I, 35% developed fibroarthrosis postoperatively that required arthroscopic lysis of adhesions and manipulation to restore motion. In Group II, only 12% developed this complication. However, developing this complication did not affect a patient's long-term clinical result when properly recognized and promptly treated.

Patellar tracking abnormalities: clinical experience with kinematic MR imaging in 130 patients

A kinematic magnetic resonance (MR) imaging technique for assessment of malalignment of the patella, involving the acquisition of multiple sequential axial images of the patellofemoral joint during the early increments of passive knee flexion, was used to evaluate 130 patients (235 symptomatic patellofemoral joints) showing clinical evidence of having patellar tracking abnormalities. Twenty-three of the patellofemoral joints had undergone previous surgical procedures for patellar realignment. In addition, 14 (28 patellofemoral joints) asymptomatic control subjects were studied. Normal patellar tracking was observed in all of the asymptomatic subjects and in 43 (17%) of the 260 patellofemoral joints in the patient population, 18 (7%) of which were symptomatic. Sixty-nine (26%) of the patellofemoral joints had lateral subluxation of the patella, 106 (41%) had medial subluxation of the patella, 21 (8%) had excessive lateral pressure syndrome, 19 (7%) had lateral-to-medial subluxation of the patella, and two (1%) had dislocation of the patella. Of the 235 patellofemoral joints with suspected abnormalities, 217 (93%) had patellar malalignment. Of the 23 patellofemoral joints that had undergone prior surgery, 20 (87%) had abnormal patellar tracking. Thirteen of 14 (93%) patellofemoral joints that had undergone a prior arthroscopic lateral retinacular release had a medially displaced patella.