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Diagnosis of patellofemoral malalignment by computed tomography.

Conventional radiographic assessment of the patellofemoral joint (PFJ) is often unsatisfactory for a variety of technical and theoretical reasons. Using a simple device designed to allow easy and reproducible control of knee flexion, we used computed tomography (CT) to evaluate the PFJ in 10 normal volunteers and five patients with a history suggestive of recurrent subluxation or dislocation of the PFJ. At full extension of the knee the patients with a history of malalignment showed an abnormal patellar centralization and tilt compared with those of the normal volunteers. The abnormalities were absent or less pronounced on images obtained at 20 and 45 degrees of knee flexion.

Humans↗

Patellofemoral malalignment: a report of 68 cases treated by proximal and distal patellofemoral reconstruction.

A series of 68 knees were reviewed retrospectively at an average of 56 months following surgical treatment for patellar dislocation and subluxation. Fifty-three knees in 48 patients were assessed both subjectively by questionnaire and objectively by examination, and 15 knees were evaluated by questionnaire only. All cases were treated by a proximal and distal reconstruction as described by Trillat (1964). The surgery was performed by one surgeon (MC) and reviewed independently (DW). The results were excellent in 48 knees (71 per cent), good in 12 (17 per cent) and poor in 8 (12 per cent). In no patient had there been any further episodes of dislocation. We consider this a straightforward procedure producing consistent correction of patellofemoral instability with a low morbidity.

Adolescent↗

[Results in patello-femoral joint replacement in various knee endoprostheses (Type GSB and ES)].

105 patients with 137 total knee replacements (105 model GSB, 32 model ES) were reexamined 4.3 years (2 to 9.7 years) postoperatively. 63.9 percent suffered from chronic polyarthritis. The clinical result (Insall 100-point score) averaged 73.6 points (78.2 ES-, 71.7 GSB II-knees). In 28.6 percent of the GSB- and 3.1 percent of the ES-knees osteolyses of the patella were apparent. Subluxation or complete dislocation of the patella was present in 85.7 percent of the GSB- and 25 percent of the ES-knees. The result was dependent on the preoperative knee axis, patellar height and the implant site of the tibial component. Revisions with complete removal of the inlay were most successful.

Adult↗

A distinct form of spondyloepimetaphyseal dysplasia with multiple dislocations.

Three unrelated patients with identical radiological features are presented. Hypotonia was noted at birth and one patient was diagnosed as having congenital fibre type disproportion in the neonatal period. Later muscle biopsies, however, were entirely normal. All patients, now in their teens and twenties, are of normal intelligence, show striking epiphyseal and metaphyseal changes of the long bones, and have joint laxity and multiple dislocations of large joints, which are particularly incapacitating at the knees. These three cases represent a sporadic, previously unreported skeletal dysplasia with spondyloepimetaphyseal distribution and multiple large joint dislocations.

Adolescent↗

Hip arthrodesis. A long-term follow-up.

In a retrospective study, we examined twenty-eight patients who had had an arthrodesis seventeen to fifty years previously (average, thirty-five years). Hip and knee ratings were obtained, as well as anteroposterior and flexion-extension radiographs of the lumbar spine and standing anteroposterior radiographs of the knees and hips. About 60 per cent of the patients had pain in the ipsilateral knee (average time to onset, twenty-three years after arthrodesis), and a similar percentage had back pain (average time to onset, twenty-five years after the operation). Pain in the contralateral hip occurred in approximately 25 per cent of the patients (average time to onset, twenty years after arthrodesis). Only one patient was unemployed due to disabling pain in the back or knee. Seventy per cent of the patients could walk more than one mile (1.6 kilometers), and a similar percentage could sit comfortably for at least two hours. Seventy-five per cent of the patients had anteroposterior laxity of the ipsilateral knee, and 80 per cent had mediolateral laxity. The patients whose hip was fused in some abduction more frequently had pain in the ipsilateral knee and the back, and they had greater degenerative changes in the ipsilateral knee than the patients whose hip was fused in adduction or in the neutral position. Six patients had undergone total hip arthroplasty for pain in the back or the ipsilateral knee, or both, and all had marked relief of back pain, while two of four had relief of pain in the knee. Two patients had a total knee arthroplasty for relief of pain in the ipsilateral knee.

Activities of Daily Living↗

Patellofemoral relationships in recurrent patellar dislocation.

Magnetic resonance imaging was used to analyse the patellofemoral relationships during the first 30 degrees of knee flexion in women with recurrent patellar dislocation. The patellofemoral joints were imaged both sagittally and axially with the knee flexed 0 degrees, 10 degrees, 20 degrees, and 30 degrees. At the beginning of knee flexion the sulcus angle was greater than in unaffected women, the lateral patellofemoral angle was smaller, the patella displaced further laterally, tilted more laterally and the congruence angle was directed more laterally. At 30 degrees of knee flexion these differences were less marked than at 0 degree to 10 degrees. Logistic regression analysis showed that the sulcus angle at 10 degrees of knee flexion was the most diagnostic feature, indicating that there is an anatomical predisposition to recurrent dislocation and that pathological patellar tracking starts from the beginning of flexion. Traditional sunrise radiographic films taken at 25 degrees to 30 degrees knee flexion clearly miss diagnostically important information.

Adolescent↗

Acute and chronic avulsive injuries.

Avulsive injuries are common traumatic lesions, especially in young athletes. They can be acute, resulting from excessive tensile forces, or chronic, due to overuse. Avulsion injuries can resemble osteomyelitis or neoplasm and, therefore, familiarity with the radiographic patterns as well as the different muscle attachments is helpful for the clinician to arrive at the correct diagnosis. This article discusses acute and chronic avulsive injuries in the pelvis, knee, elbow, shoulder, and foot.

Acute Disease↗

Orthopaedic measurements with computed radiography. Methodological development, accuracy, and radiation dose with special reference to the weight-bearing lower extremity and the dislocating patella.

The overall aim of this study was to develop and evaluate a measurement system for computed radiography (CR) and Picture Archiving and Communication Systems (PACS), permitting measurements of long distances and angles in and between related images. The developed measurement system, which was based on the QUESTOR Precision Radiography (QPR) system, was applied to the weight-bearing knee with special reference to the dislocating patella. The QPR system modified for CR fulfilled the criteria for measuring the weight-bearing knee. The special measuring assistance tools that were developed were important for the implementation of CR and PACS, particularly in workstations programmed for musculoskeletal radiology. The energy imparted to the patient was reduced by 98% at the lowest exposure of the CR-system, compared with our conventional analogue method, without loss of diagnostic accuracy. The CR technique creates a possibility, to an extent not previously feasible, to differentiate the exposure parametres (and thus minimise the radiation dose to the patient) by carefully considering the purpose of the examination. A radiographic method for measuring the rotation of the femur and the tibia, the Q-angle, and the patellar translation was developed and applied to healthy volunteers. The introduced patellar variables have yielded new insights into the complex sequence of motions between the femur, tibia, and patella. The patients with a dislocating patella were subdivided into one "clean" group of spontaneous dislocations and one group with various traumas in the history, which thus resulted in two groups with distinct radiographic differences. The Q-angle was decreased in knees that had suffered dislocations, and the traditional surgical treatment with a further reduction of the Q-angle must be challenged. The use of clinical measurements of the Q-angle was not an optimal way to evaluate the mechanical alignment in the patellofemoral joint under physiological conditions. In this study, we have proved that the developed method for CR and PACS is a useful technique for measurements in and between related images, and is superior to the conventional analogue technique.

Adolescent↗

Arthroscopic removal of a loose body osteophyte fragment after superior patellar dislocation with locked osteophytes.

The authors report the case of a loose body from a fractured osteophyte after a superiorly dislocated patella with locked osteophytes. Few cases of superiorly dislocated patellae have been reported in the literature and no cases of osteophyte fracture fragments after locked osteophytes with subsequent arthroscopic loose body removal have been reported. The loose body was removed and the distal pole of the patella was debrided arthroscopically. This patient and the majority of previously reported cases, herein reviewed, had patella alta with pre-existing patellofemoral arthrosis. Patella alta in the face of patellofemoral arthrosis should be considered a risk factor for loose body formation. Therefore, recurrent superior patellar dislocation and locking osteophytes may be a relative indication for pre-emptive arthroscopic debridement of locked osteophytes.

Arthroscopy↗

Progressive subluxation and polyethylene wear in total knee replacements with flat articular surfaces.

One hundred eighty-six Microloc tricompartmental, cruciate-sparing, primary total knee replacements in 136 patients were performed between 1983 and 1987. Femoral components were made of cobalt-chrome-molybdenum alloy. The tibial component baseplates were made of titanium-aluminum-vanadium alloy. The baseplates were made with three small porous-coated pegs for fixation with or without cement, or with a central stem for fixation with cement. The polyethylene was affixed to the baseplate by a mechanical locking mechanism that was nonmodular. The articular surfaces of both components were flat mediolaterally and anteroposteriorly. The patellar components were dome shaped and metal backed with titanium-aluminum alloy. Seventy-three percent of the femoral components, 26% of the tibial components, and 48% of the patellar components were inserted without bone cement. The average time to maximum follow-up examination was 6.1 years (range, four to nine years). Of implants that had not been revised, 84.4% had good or excellent results (using the Hospital for Special Surgery scoring system) at final follow-up examination. The average range of motion of functioning implants at final follow-up examination was 108 degrees. Revisions for failure only of the metal-backed patellar component were performed in 22 knees (11.8%). Forty knees (21.5%) required revision for failure of the femoral-tibial articulation. Reasons for failure in this group included: polyethylene wear (57.5%); loosening (15.0%); tibial tray fracture (10.0%); sepsis (12.5%); and dislocation or ligament laxity (5.0%). An additional 15 functioning knees (8.1%) have radiographic evidence of progressive femoral-tibial subluxation. Future failure of these devices is considered likely. Polyethylene wear requiring revision was not statistically associated with patient age, gender, preoperative diagnosis, height, weight, or component size. Polyethylene failure leading to revision was related to the radiographic appearance of femoral-tibial component subluxation. This subluxation was most likely to occur after five years of component implantation. The development of progressive femoral-tibial subluxation was statistically associated with postoperative extremity malalignment, excessive varus positioning of the tibial component, bone grafting of the tibial plateau, the use of the small-pegged tibial component, and the use of this component without cement. Polyethylene wear associated with progressive femoral-tibial subluxation occurred at the periphery of the tibial plateau and along the raised portion of the tibial spine. The metal baseplate at the edge of the plateau was frequently exposed and worn. Bone lysis associated with the presence of polyethylene, metal, and cement debris was frequently observed.

Adult↗

[Quadriceps dysplasia and patellar tilt in objective patellar instability].

PURPOSE OF THE STUDY: Dysplasia of the vastus medialis, a well-known landmark of patellar instability, is difficult to point out pre-operatively. We propose the measurement of patellar tilt on the CT scans in order to appreciate abnormality. MATERIAL AND METHODS: We studied 3 well defined groups: 143 knees operated on for a true dislocation of the patella, either for the first time or a recurrent episode, 67 asymptomatic and nonoperated contralateral knees and 54 control knees. The patellar tilt in extension was measured on the CT-scan with the quadriceps relaxed and contracted. RESULTS: The results showed the increase of the patellar tilt as an characteristic factor of patellar instability (28.8 + 10.5 degrees against 11.8 degrees + 5.7 degrees in the control group). Patellar tilt was not a consequence of the dislocation because it was also significantly increased in the asymptomatic contralateral group (17 degrees + 9 degrees). Quadricipital contraction increased the patellar tilt only in the two groups of patellar instability (+ 6 degrees) and asymptomatic contralateral group (+ 13 degrees) but not in the control group (+ 1.6 degrees). The mean of the relaxed and the contracted quadriceps patellar tilt includes the dynamic trouble. We propose the threshold of 20 degrees to determine a pathological patellar tilt. In this case, sensibility is 90 per cent and the specificity is 91 per cent. In the other patellar instability factors, only severe trochlear dysplasias involved the patellar tilt. DISCUSSION: We think that the patellar tilt in extension is a landmark of a functional disorder of the whole quadriceps muscle more than the vastus medialis only. The mean of the relaxed and contracted quadriceps patellar tilt measures permitted to point out the border cases of this functional abnormality. This measurement is reliable and can be considered pathologic above 20 degrees. The results of Insall's muscular plasty were only symptomatic because this procedure could not correct the effect of the quadricipital contraction.

Adolescent↗

Referred knee pain treated with electroacupuncture to iliopsoas.

This is a case report of a 33-year-old woman who presented with an eight year history of deep left knee pain. The pain was originally diagnosed as deriving from osteoarthrosis of the hip secondary to dysplasia, however, the same pain returned at seven months, and again at 10 months, after successful hip resurfacing arthroplasty. Six to eight weeks after the start of the second relapse of referred knee pain, the patient sought acupuncture treatment at the British Medical Acupuncture Society's London Teaching Clinic. A single myofascial trigger point was found in iliopsoas that reproduced the patient's pain. It was successfully treated with two sessions of electroacupuncture applied directly to the point. Pain referral to the knee from trigger points in the upper part of rectus femoris is well recognised, however, this pattern of referral from iliopsoas has not been described previously.

Acupuncture Points↗

[Orthopaedic problems in adults with cerebral palsy].

BACKGROUND: There is little information about the need for orthopaedic surgery in adults with cerebral palsy; we wanted to assess this problem. MATERIAL AND METHODS: The material included 37 adults with cerebral palsy (19 women and 18 men), mean age 39. The degree of physical disability was mild in 19 cases, moderate or severe in 18. The patients were assessed by clinical examination and radiographs of hips and spine. RESULTS: 15 patients had pain located to the spine or lower extremities but no-one had severe or invalidating pain. Subjects with moderate or severe disability had a markedly reduced range of motion in the hip and knee joints. Subluxation or dislocation of the hip joints was found in six patients but only one of them had hip pain. Orthopaedic surgery had been performed in 23 patients. In 8 patients we found indications for additional orthopaedic surgery aimed at relieving pain, reducing contractures or improving function. The most frequent procedures would be tenotomies in the hip and knee regions, heel cord lengthening, and triple arthrodesis of the foot. INTERPRETATION: Regular follow-up of adults with cerebral palsy is recommended in order to reveal musculoskeletal problems that can be improved by orthopaedic surgery.

Adult↗

Dislocations following arthroplasties of the hip. Incidence, prevention, and treatment.

Three methods of avoiding postoperative prosthetic dislocation following total or bipolar hip arthroplasty are described; each approach is recommended for a specific population. The anterior surgical approach was utilized for bipolar hip endoprosthetic arthroplasty in 62 minimal or bed-to-chair ambulators with established flexion contractures about the hip. Two of these patients subsequently experienced a prosthetic dislocation, one of which was secondary to infection. An additional 98 patients who underwent arthroplasty using the posterior approach wore a knee immobilizer postoperatively, without incidence of prosthetic dislocation. A modification of Wilke boot casting was utilized for four patients following reduction of a dislocated hip prosthesis. The cast consisted of a short cylinder cast on the affected extremity connected by a cross bar to a short leg cast on the contralateral leg. The casts controlled rotation, were well tolerated, and resulted in no redislocations. We therefore recommend the anterior approach in minimal ambulatory patients who are to undergo total bipolar hip arthroplasty. When the posterior approach is used in hip replacement procedures, we have found that postoperative use of a knee immobilizer helps prevent dislocation. Following reduction of a dislocated hip prosthesis, a modification of the Wilke boot cast that does not immobilize the affected ankle can be used.

Aged↗

Preoperative planning to prevent instability in total knee arthroplasty.

Several factors can lead to persistent instability after total knee arthroplasty, including bone and soft tissue loss, preexisting ligamentous laxity, and poor operative technique. Achieving stability should not be equated with making the knee extremely tight, without any natural laxity.

Arthroplasty, Replacement, Knee↗

Instability of the patellofemoral joint in Down syndrome.

The knees of 210 institutionalized patients with Down syndrome were evaluated to determine the prevalence of patellofemoral instability and to assess the value of orthotic and surgical treatment. The cases of 151 non-institutionalized patients with Down syndrome were also reviewed. The patella was dislocatable or dislocated in thirty-five knees (8.3 per cent) in the institutionalized group and in twelve knees (4.0 per cent) in the non-institutionalized group. This interfered with walking in some patients, but only three of the patients were unable to walk because of patellofemoral instability. None of the institutionalized patients used any form of orthosis, and only three non-institutionalized patients used an orthosis. Eight knees in five patients had been operated on, and they had an average length of follow-up of 16.8 years. Four of these knees had a satisfactory result. Instability of the patellofemoral joint may occur in patients with Down syndrome but is rarely disabling. Almost all patients with patellofemoral instability adapted to the problem and were able to walk.

Adaptation, Physiological↗