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PubMed1980

Resurfacing of the patella.

The results of use of twenty-nine patellar resurfacing prostheses in twenty-eight patients were studied. The diagnosis was osteoarthritis in twenty-two knees, chondromalacia in five knees, and habitual dislocation with severe osteoarthritis in two. The follow-up time was from three to six years. A cemented chromium-cobalt prosthesis was used. Of the twenty-nine knees studied, two were rated excellent; fourteen, good; three, fair; and ten, poor. Failure was always due to unrelieved pain.

Adolescent↗
PubMed2006

Hybrid medial patellofemoral ligament reconstruction using the semitendinous tendon for recurrent patellar dislocation: minimum 3 years' follow-up.

PURPOSE: The purpose of this study was to evaluate the results of a new hybrid medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar dislocation. METHODS: Hybrid MPFL reconstruction by use of the semitendinous tendon was performed in 12 knees with recurrent patellar dislocation. The results were evaluated at a minimum follow-up of 3 years (mean, 4.2 years). RESULTS: According to the grading system of Insall et al., the results were classified as excellent in 8 knees (66%), good in 2 (17%), and fair in 2 (17%), with none being classified as poor. The mean Kujala score was 56.3 points (range, 29 to 82) preoperatively and 96.0 points (range, 84 to 100) at follow-up. There were no patients with recurrent dislocation and subluxation. No knees had a positive apprehension sign, and there were no postoperative complications. CONCLUSIONS: At a midterm follow-up, hybrid MPFL reconstruction by use of the semitendinous tendon for recurrent patellar dislocation should be considered as an effective operation for cases without severe predisposing factors. LEVEL OF EVIDENCE: Level IV, therapeutic case series, no or historical control group.

Adolescent↗
PubMed2002

Morphology of the knee in adult patients with neglected developmental dysplasia of the hip.

BACKGROUND: Although there have been numerous studies on the treatment of developmental dysplasia of the hip, few have focused on its natural history into adulthood. We observed valgus deformity of the knee in a group of adult patients with developmental dysplasia of the hip. To the best of our knowledge, there has been no detailed study of that condition. The purpose of this study was to investigate structural changes of the knee in patients with neglected developmental dysplasia of the hip. METHODS: Thirty-four adult patients with neglected developmental dysplasia of the hip and ten healthy adults were evaluated. The lower extremities were grouped according to the severity of the dysplasia. The morphology of the knees was evaluated with radiographic measurements, and the groups were compared. RESULTS: Compared with the control group, the patients with severe developmental dysplasia of the hip had significant valgus deformity of the knee. This finding was associated with an increased vertical dimension of the medial femoral condyle, which led to a valgus inclination of the distal femoral articular surface. Although the femoral sulcus was shallower in the patients with developmental dysplasia of the hip, patellofemoral congruency was not deranged. CONCLUSIONS: The pathologic condition of the hip joint in patients with developmental dysplasia of the hip results in developmental changes in the osseous anatomy of the knee joint, with the development of a valgus deformity of the lower extremity. If any surgical intervention is planned in a patient with developmental dysplasia of the hip, the whole lower extremity should be carefully analyzed, with special attention to the morphology of the knee, to avoid creating problems of malalignment.

Adolescent↗
PubMed2005

Cadaveric study on static medial patellar stabilizers: the dynamizing role of the vastus medialis obliquus on medial patellofemoral ligament.

Aim of this cadaveric biomechanical study was to describe the detailed anatomy of the static medial patellar stabilizers and further determine the role of each of them in preventing lateral patellar dislocation. Eight cadaver knees, after removing the skin and subcutaneous tissues, were used in the study. The medial patellofemoral ligament (MPFL), the medial retinaculum (MR) the medial patellomeniscal ligament (MPML), and the medial patellotibial ligament (MPTL) were dissected. Their origins, insertions, orientations and sizes were recorded. To the medial stabilizers, a tension of 10 pounds was applied, using a tensiometer held in a semicircular device while the knees were kept in 30 degrees of flexion. Then, the previously described ligaments were dissected and the resultant displacement recorded. The most anatomically distinct structure is the MPFL, whose length varies from 45-50 mm, and its width from 10-20 mm at its origin (medial femoral epicondyle) to 20-30 mm at its insertion to the patella. The "meshing" of the MPFL fibers to the fibers of the vastus medialis obliquus (VMO) close to its patellar insertion was the most interesting and very important finding. The contribution of MPFL to medial stability was more than 50%. Of the remaining ligaments, MPML contributes 24% and the MPTL and MR contribute only 13% respectively. The MPFL is the strongest medial static patellar stabilizer. Its contribution to patellar stability against lateral dislocation is far more than 50%, since its meshing with the VMO, shortens its fibers which thus pulls the patella to the medial part of the femoral groove and keeps it in the trochlea during the initial 20 degrees -30 degrees of flexion.

Biomechanical Phenomena↗
PubMed1977

[Congenital dislocation of the hip: an osteo-neural growth disturbance (author's transl)].

Congenital dislocation of the hip may be readily explained as the result of the osteo-neural growth-in-length disproportion. The theoretical concept is supported by experimental findings in frog tadpoles with "congenital" dislocation of the knee joint produced by osteolathyrogenic diet. In cleared specimens with selective staining of the nervous trunks according to Williams (1943) a growth inhibition of the sciatic nerve responsible for the proximal shift (dislocation) of the tibia may be noted. The tibia is adapted to the growth peculiarities of the sciatic nerve in an essentially similar way like the bony neurocranial capsule to the growing brain. The suggested pathogenetic mechanism appears to apply even to the congenital dislocation of the hip in man.

Animals↗
PubMed1993

The incomplete bicruciate knee injury. A report of two cases.

Two patients suffered similar knee injuries due to valgus stress and hyperextension. Examination under anesthesia and arthroscopic evaluation revealed a previously unreported ligament injury pattern. Both patients had a complete tear of the anterior cruciate ligament and a partial tear of the posterior cruciate ligament; neither was noted to have a dislocation. The descriptive term identifying this injury pattern is "incomplete bicruciate knee injury." The purpose of this report is to identify this knee-injury complex, which appears to be part of the sequence that leads to complete tears of both cruciate ligaments--the classic knee dislocation.

Adolescent↗
PubMed1995

[Experimental capsulo-ligamentar lesions of the knee during passive hyperextension. Biomechanical aspects. A lesional evaluation and consequences].

PURPOSE OF THE STUDY: Passive hyperextension is a rare mechanism of injury of knee ligaments in clinical practice. The lesions are often complex and no consensus exists about their sequence. Our purpose was to study the mechanical behavior and the anatomical lesions of the knee following passive hyperextension until rupture. MATERIAL AND METHODS: 12 pairs of fresh human cadaveric knees were tested after resection of soft tissue except for the ligaments and the Popliteus muscle. Some of them had specific ligaments sections (PCL or posterior capsule). We used a "four point bending" model at a constant rate (V = 3 10E-4 m/s) and measured failure torque and bending stiffness of the knee. Results were expressed as percent of the response of the normal contra lateral knee. RESULTS: A wide range of absolute data was noted and correlated to the age and bone quality. Bony avulsion was constant. The posterior capsule was the first structure injured at an average of 23 degrees of recurvatum, followed by the posterolateral ligament. The PCL was the ultimate structure to fail at its femoral attachment, preceding complete dislocation of the knee. No ruptures of the ACL and medial collateral ligament were noted. After section of the posterior capsule, the stiffness of the knee decreased 40 to 80 percent compared to the normal opposite knee, whereas the isolated section of the PCL had no significant effect. DISCUSSION: The method used in this study appears reliable. "The four point bending" is a reproducible model and the use of paired specimens allows a quantitative approach. The use of elderly specimens at a low strain rate in this experiment remains a questionable point. Passive hyperextension is characterized by automatic external rotation resulting in asymmetrical posterior lesions and tears of the PCL at its femoral attachment. On the contrary, active hyperextension of the knee can produce ACL injury by anterior translation of the tibia under the femur consecutive to Quadriceps femoris contraction. CONCLUSION: Our experimental model is an effective and reproducible method to create passive hyperextension of the knee. The first structure to fail is the posterior capsule followed by the posterolateral ligament. The PCL is the ultimate structure to fail and no ACL rupture has been noted before dislocation. CLINICAL RELEVANCE: if passive hyperextension mechanism is suspected, isolated posterior capsule lesion may occur and should be repaired. On the contrary, PCL tear should never be isolated and always associated with peripheral ligament injuries.

Anterior Cruciate Ligament↗
PubMed1995

[A case of dislocation of a double patella].

The congenital dislocation of the patella is relatively rare and the duplicated patella associated is exceptional. The congenital character of the dislocation is unquestionable, but the etiology remains unknown. Before patellar ossification, the diagnosis is difficult and may be delayed for several years until progressive genu valgum, external tibial rotation and flexion deformity results. Radiographs are not useful in evaluating the dislocation until patellar ossification begins at approximately 4 years of age. CT scans and MR imaging reveal the diagnosis before patellar ossification and defines the magnitude of associated dysplasia and the presence of degenerative changes. Early treatment is recommended before the development of secondary bony deformity. We are reporting an unusual case of a woman with multiple epiphyseal dysplasia and bilateral congenital malformation of the patella (duplicated frontal type), associated with genu valgum and congenital dislocation of the patella. She was diagnosed at 31 years old. After surgical treatment (genu valgum correction by varus osteotomy, proximal and distal realignment of the extensor mechanism and osteosynthesis with screws of duplicated patella) and three years follow-up period, we have obtained a good result (painless knees, no recurrence of dislocation and active flexion of 100 degrees on the right knee and 120 degrees on the left knee).

Adult↗
PubMed1977

Patellar-tendon transfer by the slot-block method for recurrent subluxation and dislocation of the patella.

In sixty-five knees followed for an average of 4.5 years after treatment of subluxation or dislocation of the patella by the slot-block method of medial patellar-tendon transfer, the results were satisfactory in fifty-four (83%) and unsatisfactory in eleven (17%). Recurrent subluxation or dislocation occurred in three (5%) of the knees and was attributed to insufficient displacement. Chondromalacia of the patella became worse after transfer in three of the sixty-two knees in which the distal realignment was technically correct. Two knees (3%) required patellectomy because of patellofemoral symptoms and there were nineteen complications in seventeen knees, including loss of motion in six, wound infection in six, displacement of the bone block in three, recurrent dislocation in three, and rupture of the patellar ligament in one. The method is believed to give superior results but it is technically demanding.

Humans↗
PubMed2003

Common peroneal nerve injuries: results with one-stage nerve repair and tendon transfer.

The authors report their experience in the treatment of common peroneal nerve (CPN) injuries using a one-stage procedure of nerve repair and tibialis posterior tendon transfer. A series of 45 patients with traumatic injury and graft repair of the CPN is presented. From 1988 to 1991, the six patients elected for surgery had only nerve repair: five ultimately did not recover, while muscle contraction in the remaining patient was graded M1-2. Since 1991, nerve surgery in our clinic was associated with tendon transfer procedures (39 cases) which were followed by a satisfactory reinnervation rate. Nerve transection and iatrogenic injuries, torsion/dislocation of the knee, complex biosseous fractures of the leg, and gunshot wounds showed excellent to fair results in decreasing order: in nerve sections, muscle recovery scored M3 or M4+ in all the patients, and in nerve ruptures due to severe dislocation of the knee, it was M3 or M4+ in 85% of cases. The association of microsurgical nerve repair and tendon transfer has changed the course of CPN injuries.

Adult↗
PubMed2002

[Complex instability of the anterior knee].

Complex knee instability involves the anterior cruciate ligament (ACL) and one or more major stabilizers of the knee [medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL)]. The medial side has a high healing potential and does not need operative treatment in most cases if ACL reconstruction is performed. Reconstruction of the medial ligament complex is indicated in gross instability of the medial meniscus fixation, dislocation of the MCL into the joint, and large dislocated bony avulsions. Injuries on the lateral side do not heal spontaneously and require acute operative treatment (first 2 weeks). Frank knee dislocations and gross multiligament injuries should be reduced acutely, and the integrity of the vascular structures must be examined closely. In a European multicenter study, operative treatment with reconstruction of both cruciate ligaments and functional rehabilitation gave better results than conservative treatment with immobilization of the joint.

Anterior Cruciate Ligament↗
PubMed2002

Dislocation of the bearing of the Oxford lateral unicompartmental arthroplasty. A radiological assessment.

When the Oxford unicompartmental meniscal bearing arthroplasty is used in the lateral compartment of the knee, 10% of the bearings dislocate. A radiological review was carried out to establish if dislocation was related to surgical technique. The postoperative radiographs of 46 lateral unicompartmental arthroplasties were analysed. Five variables which related to the position and alignment of the components were measured. Dislocations occurred in six knees. Only one of the five variables, the proximal tibial varus angle, had a statistically significant relationship to dislocation. This variable quantifies the height of the lateral joint line. The mean proximal tibial varus angle for knees the bearings of which had dislocated was 9 degrees and for those which had not it was 5 degrees. In both groups it was greater than would be expected in the normal knee (3 degrees). Our study suggests that a high proximal tibial varus angle is associated with dislocation. The surgical technique should be modified to account for this, with care being taken to avoid damage to or overdistraction of the lateral soft tissues.

Aged↗
PubMed1988

A chronically dislocating prosthetic patella. A case report.

A 63-year-old white woman was evaluated for a chronically dislocating right patella 6 months following total knee arthroplasty. At the time of our initial evaluation, her knee would not extend beyond 35 degrees and her patella was dislocated and irreducible. At arthrotomy, when the patella was everted, the patellar component was oriented with the facet ridge rotated 90 degrees to the trochlear groove of the femoral component. The patellar template guide indicated that the fixation pegs had been drilled properly, and thus, the patellar component had been assembled improperly during manufacturing. After dome-type patellar prosthesis replacement and proximal and distal extensor realignments were performed, 2 months post-revision the patient had a range of motion from 5 degrees to 95 degrees and ambulated with no patellar instability or pain.

Equipment Failure↗
PubMed2005

[Total knee replacement in valgus knee].

OBJECTIVE: To investigate the methods and clinical results of total knee replacement (TKA) in patients with valgus knee deformity. METHODS: Between January 1996 and August 2004, 87 TKAs were performed by means of medial parapatellar approach, standard osteotomy and only lateral soft tissue release with posterior stabilized implants on 74 patients (11 men and 63 women) with valgus deformity. The average age at the time of operation was 62.93 years (range, 26-80 years). Clinical and radiographic evaluations including range of motion (ROM), Knee Society Score System (KSS) and the tibial and femur angle (T-F angle) were performed at follow-up. RESULTS: After a mean follow-up of 33.8 months (range, 5 months-9 years), the average ROM improved from 91 degrees (range, 70 degrees-120 degrees) preoperatively to 112.4 degrees (range, 80 degrees-130 degrees) postoperatively, the average KSS improved from 22.7 points (0-48 points) preoperatively to 81.7 points (range, 71-93 points) postoperatively. The average function score improved from 26.5 points preoperatively to 86.3 points postoperatively, the average T-F angle was corrected from 21.59 degrees (range, 12 degrees-40 degrees) of valgus preoperatively to 8.7 degrees (0 degrees-11 degrees) of valgus postoperatively. One knee had lightly instability at follow-up, one knee with patellar dislocation preoperatively had subdislocation postoperatively, no other complication occurred. CONCLUSIONS: The techniques of medial parapatellar approach, standard osteotomy and only lateral soft tissue release with posterior stabilized implants can correct a fixed valgus deformity very successfully in patients undergoing primary total knee replacement, and provides excellent results.

Adult↗
PubMed1992

Locked patellar dislocation with vertical axis rotation. A case report.

Whereas traumatic lateral dislocation of the patella is a well-described clinical entity, other types of patellar dislocations, specifically those that involve patellar rotation, are unusual. These rare types also present a therapeutic problem in which reduction often requires a general anesthetic and, possibly, an open procedure. A 16-year-old boy sustained a laterally directed blow to his knee, resulting in dislocation of the patella. The patella had rotated 90 degrees in the vertical plane and became wedged against the lateral femoral condyle. Initial attempts at closed reduction in the emergency room and under general anesthesia in the operating room were unsuccessful, and the patient required open reduction. A similar type of dislocation has been described; however, the patella is usually intercondylar. The tear along the medial side was extensive enough to allow the patella to dislocate lateral to the lateral femoral condyle, making this a unique case. In these instances of rare patellar dislocation, the surgeon should be prepared to perform an open reduction, because attempts at closed reduction even with a general anesthetic may be unsuccessful.

Adolescent↗
PubMed2000

Silent compartment syndrome complicating total knee arthroplasty: continuous epidural anesthesia masked the pain.

Posterior dislocation is an uncommon complication of total knee arthroplasty (TKA) using a posterior stabilized total knee prosthesis, and it usually results from flexion instability. Acute posterior dislocation of a posterior stabilized prosthesis complicated by compartment syndrome of the leg has not previously been reported in the literature. We report a 62-year-old woman with posterior dislocation of her posterior stabilized TKA when her knee was in extension. It was further complicated by compartment syndrome with severe muscle necrosis. The diagnosis of compartment syndrome was delayed, partly because of continuous epidural anesthesia that completely abolished the pain and partly because of the low index of suspicion, as compartment syndrome is not well recognized as a possible complication of TKA. This case report strongly emphasizes that continuous epidural anesthesia is contraindicated in the case of complicated TKA because important clinical cues to neurovascular complications could be masked.

Anesthesia, Epidural↗