Medial patellar ossification after patellar instability: a radiographic finding indicative of prior patella subluxation/dislocation

Objective  To describe the correlation between medial patellar ossification and prior patella subluxation and/or dislocation. Materials and methods  A retrospective billing database search identified 544 patients who had been diagnosed with patellar instability over a 13-year period. One hundred twenty-eight patients met the inclusion criteria. After review by a staff orthopedic surgeon and two musculoskeletal radiologists, 28 patients were found to have medial patellar ossification. The size and location of medial patellar ossification was recorded. Results  Of the 28 patients (20 males, eight females, age 13–66 years, mean 28 years) who were found to have medial patellar ossification, 22 had radiographs, 16 had magnetic resonance imaging, and ten had both. The medial patellar ossification ranged in size from 2 to 18 mm with an average of 6.8 mm. Twelve were located in the medial patellofemoral ligament (MPFL), 14 in the medial joint capsule, and two in both the MPFL and joint capsule. Twenty-seven of 28 patients had a single ossification, and one patient had two ossifications. The timing from injury to first imaging of the lesion ranged from 10 days to a chronic history (≥35 years) of patellar instability. Conclusion  Medial patellar ossification correlates with a history of prior patella subluxation and/or dislocation. The medial ossification can be seen within the MPFL or the medial joint capsule, suggesting remote injury to these structures. The presence of this lesion will prompt physicians to evaluate for patellar instability.     

The double patella syndrome

First described by A. Trillat, the double patella is an uncommon clinical feature following repetitive injuries of the extensor mechanism of the knee. The first injury is a tendo-periosteal avulsion of the suprapatellar or, less frequently, infrapatellar tendon from the corresponding patellar pole. Often these avulsions are misdiagnosed and therefore treated only with a cast or no immobilization at all. Subsequent giving-way episodes lead to extensive ossification which is adjacent to or separated from the patella. The peculiar shape of this ossification overriding or underlying the primary kneecap justifies the denomination of double patella. Surgical treatment consists of removal of the calcification and reattachment of the tendon to the patella by transosseous sutures.     

The immature athlete

The skeletally immature athlete poses unique problems in diagnosis and treatment of injuries to the extensor mechanism of the knee. An accurate and detailed history and physical examination of the knee are essential for making a specific diagnosis and formulating an appropriate treatment plan. This article presents an overview of acute and chronic injuries of the extensor mechanism of the knee that are unique to skeletally immature athletes. The subjects of femoral trochlear dysplasia and medial subluxation of the patella are briefly discussed. The etiopathology, clinical evaluation, and management (non-operative and operative) of sleeve fractures of the patella and avulsion fractures of the tibial tubercle in children and adolescents are discussed. The pathoanatomy, clinical features, and management of synovial plica syndrome, Hoffa's syndrome, Osgood-Schlatter disease, and Sinding-Larsen-Johansson disease are presented.     

Drug Testing in Sports

In brief Because of their skeletal immaturity, children and adolescents are subject to a somewhat different set of overuse knee injuries than are adults. Described here are the diagnosis and treatment for the most common growth-related causes of knee pain in active young people: Osgood-Schlatter disease, Sinding-Larsen-Johansson disease, osteochondritis dissecans, bipartite patella, medial plica syndrome, and discoid meniscus. In most cases these conditions respond to conservative treatment.     

Clinical features and classification of bipartite or tripartite patella

The purposes of this study were to report clinical features of the developmental anomaly of ossification type bipartite or tripartite patella using a large series and to propose a new classification for the developmental anomaly of ossification type bipartite or tripartite patella. The first author prospectively examined 111 patients with symptomatic or asymptomatic bipartite (131 knees) or tripartite (8 knees) patellae. Eighty-six (77%) were male and 25 (23%) were female. Forty-three patients (39%) showed right knee involvement and 40 (36%) showed left, while 28 (25%) showed involvement in both knees. Forty-six bipartite and 4 tripartite patellae (36%) were symptomatic and 85 bipartite and 4 tripartite patellae (64%) were asymptomatic at initial examination. The median age at onset of pain of symptomatic patients (50 knees) was 15.6 ± 8.1 years (range, 10–51 years). The most common symptom was pain at the separated fragments during or after strenuous activity in all 50 knees. Physical examination revealed localized tenderness over the separated fragments in all 50 knees. Bipartite or tripartite patellae were classified by evaluating location and number of fragments. One hundred fifteen knees (83%) were classified as supero-lateral bipartite type, 16 (12%) were lateral bipartite type, 6 (4%) were supero-lateral and lateral tripartite type, and 2 (1%) were supero-lateral tripartite type. For the developmental anomaly of ossification type bipartite or tripartite patella, a classification based on both location and number of fragments is simple and easy to understand and applicable to all types of bipartite or tripartite patella.     

Intensive training in young athletes. The orthopaedic surgeon's viewpoint

A young athlete's musculoskeletal system is unique, in that it is not only growing, but is giving support to the growing soft tissues as well. With this in mind, it is easily understood that the fastest growing areas of children skeletal system are at greater risk of injury. No controlled longitudinal studies have yet been performed about the long term effects of injuries occurring in intensively trained young athletes. During the growth spurt, a dissociation between bone matrix formation and bone mineralisation occurs, thus leaving the child with the risks of chronic moderate-to-high overloading, sudden great overload, and diminished bone strength. This may account for both acute and overuse bone injuries in this age group. Epiphyseal plate injuries can have disastrous consequences. About 10% of all skeletal trauma in children involves the epiphysis, but few long-lasting effects have been reported. It is not clear whether intensively trained young athletes are at greater risk of injury than children engaged in free-play activities. It is worrying, though, that about 20% of injuries in sports children require internal fixation. Few studies have addressed injuries to tendons, ligaments and the enthesis in young athletes. It seems that tendon injuries are mild, not requiring surgery, and with a low recurrence rate, but no prospective studies have been performed. Avulsion of the ligamentous insertion occurs more frequently than ligament ruptures in this age group, even though they seem on the increase. Osteochondritis dissecans affects weightbearing joints such as the hip, the knee and the ankle, but elbow lesions in gymnasts and throwers are also relatively frequent. If it occurs before epiphyseal fusion, long term effects are scarce. The centre of growth or ossification where a major tendon is attached may undergo chronic inflammation and avulsion of cartilage and bone, due to the stresses transmitted to it. Typical areas are the inferior pole of the patella, the tibial tubercle and the calcaneal apophysis. Sports activity contributes to the disease by excessive traction at the tendinous and fascial insertion, or as a result of direct pressure. The lumbar spine is subjected to enormous forces in some sports. The true incidence of lumbar disc lesions in sporting children is not known, but it seems that acute trauma may play a major role. With the increase of the intensity and duration of training programmes, degenerative changes may play an adjuvant role.(ABSTRACT TRUNCATED AT 400 WORDS)     

Complications in the multiple-ligament-injured knee

Multiple-ligament knee injuries require careful evaluation to make an accurate diagnosis and to identify associated neurovascular injuries that can threaten limb viability. Other concomitant bony and soft-tissue injuries may include open joint injuries, fracture-dislocations, and compartment syndrome. Surgical reconstruction of multiple-ligament knee injuries requires careful preoperative planning and surgical timing to decrease the potential for iatrogenic neurovascular injuries and wound complications. Postoperative loss of motion and residual instability can result in severe functional deficits. Other complications related to surgical reconstruction may include tourniquet problems, anterior knee pain, medial femoral condyle ostenecrosis, heterotopic ossification, and compartment syndrome. This article reviews the complications that are often associated with multiple-ligament knee injuries.     

Incarcerated patellar tendon in Hoffa fracture: an unusual cause of irreducible knee dislocation

Irreducible knee dislocation due to incarcerated soft tissue structures in associated fractures is extremely uncommon. We report a case of irreducible, closed dislocation of the knee secondary to incarcerated patellar tendon in a Hoffa fracture (unicondylar fracture of femur in the coronal plane) with associated communited fracture of patella and disruption of both cruciates. We treated this case initially with open reduction and internal fixation of fracture and repair of the patellar tendon. During the total followup period of eighteen months, the patient had restricted joint range of motion with no joint instability despite aggressive physiotherapy and further surgical intervention. The prognosis of such complex knee injuries with combination of ligamentous injuries and associated fractures is much worse when compared to either injuries alone.     

Painful bipartite patella following injury: a case report

Bipartite patella is a normal variation in ossification development. This variation is usually asymptomatic but can cause persistent and debilitating anterior knee pain with an injury.We report the case of a 56-year-old man complaining of persistent anterior left knee pain following trauma.Standard knee radiographs show a bilateral Bipartite Patella appearance, and magnetic resonance imaging shows discrete bony edema of the cancellous bone of the accessory bone and about the synchondrosis explaining the anterior knee pain, associated with a crack in the posterior compartment of the medial meniscus.Conservative care including medical treatment with non-steroidal anti-inflammatory drugs, physical therapy was used.Magnetic resonance imaging is the most valuable diagnostic tool for evaluating detailed morphologic and pathologic changes in patients with the bipartite patella.     

An unusual mechanism for injury of the anterior cruciate ligament in figure skating

A 20-year-old competitive figure skater presented with an acute disabling knee injury that occurred in the overhead, non-weight-bearing knee during the performance of a Biellmann spin. Examination and magnetic resonance imaging confirmed the diagnosis of a complete anterior cruciate ligament (ACL) tear. To our knowledge, no previous cases of acute injury of the ACL sustained during the execution of a Biellmann spin have been reported. The ACL injury we report is unique because it occurred without the blade contacting the ice. The mechanism of injury has some features that are similar to those of other noncontact ACL injuries, with the addition of centrifugal force as a potential contributor to the injury.     

A mini-invasive adductor magnus tendon transfer technique for medial patellofemoral ligament reconstruction: a technical note

Patellar dislocations are associated with injuries to the medial patellofemoral ligament (MPFL). Several techniques for MPFL reconstruction have been recently published with some disadvantages involved, including large skin incisions and donor site morbidity. Arthroscopic stabilizing techniques carry the potential of inadequate restoration of MPFL function. We present a minimally invasive technique for MPFL reconstruction using adductor magnus tendon autograft. This technique is easily performed, safe, and provides a stabilizing effect equal to current MPFL reconstructions. Skin incision of only 3–4 cm is located at the level of the proximal half of the patella. After identifying the distal insertion of the adductor magnus tendon, a tendon harvester is introduced to harvest the medial two-thirds of the tendon, while the distal insertion is left intact. The adductor magnus tendon is cut at 12–14 cm from its distal insertion and transferred into the patellar medial margin. Two suture anchors are inserted through the same incision at the superomedial aspect of the patella in the anatomic MPFL origin. The graft is tightened at 30° knee flexion. Aftercare includes 4 weeks of brace treatment with restricted range of motion.     

Long patellar tendon: radiographic sign of patellofemoral pain syndrome--a prospective study.

The position of the patella was studied prospectively in both knees of 45 consecutive patients (21 male and 24 female patients aged 16-48 years who were competitive [n = 17] or recreational [n = 28] athletes) who had unilateral patellofemoral pain syndrome without symptoms or signs of patellar instability at initial examination. In each knee, standardized anteroposterior, lateral, and tangential radiographs were obtained and six indexes of patellar position (the ratio of the patellar tendon to the greatest diagonal length of the patella, sulcus angles, lateral patellofemoral angle, lateral patellar displacement, patellofemoral index, and knee angle) were measured. When healthy and affected knees were compared, high riding of the patella due to long patellar tendon (patella alta) was the only definite finding in the affected knees. The shape of the intercondylar sulcus and the mediolateral position of the patella were identical in both knees, providing no evidence for patellofemoral incongruence or lateral patellar tilt. Results of this study strongly suggest that idiopathic retropatellar pain is closely associated with patella alta.     

Osteochondroses in athletes.

Osteochondroses are disorders of primary and secondary growth centres, or lesions at the apophyseal or epiphyseal growth areas of bones. Although there are many types of osteochondroses, the history, clinical symptoms and findings as well as radiological findings are typical. Physical exercise is one of the factors that provokes symptoms. In a series of 185 osteochondroses in active young athletes, there were 18 different disorders. The commonest were Osgood-Schlatter's disease, Sever's disease, osteochondritis dissecans of the femoral condyles, various other patellar osteochondroses and Scheuermann's disease. Most of the athletes were from individual events; track and field sports (53.5%), cross-country skiing (8.1%), gymnastics (3.2%) and power events (2.7%). Of the team sports soccer produced the most (20.0%). The treatment was conservative in 84.3% and operative in 15.7%. The duration of symptoms in these athletes persisted in about 43% for less than one year and in 57% for more. The late changes of osteodhondroses do not cause serious risks for a normal life, if the treatment is active and the follow-up efficient.     

Intraosseous pilomatricoma: a possible rare skeletal manifestation of Gardner syndrome

Here we report a case of intraosseous pilomatricoma in a patient with Gardner syndrome. A 17-year-old boy with a family history of Gardner syndrome and multiple cutaneous epidermoid cysts presented with pain in the region below the knee of the left leg. Plain radiographs displayed a well-circumscribed eccentric lesion of mixed radiolucent and radiopaque density within the diaphysis of the left proximal tibia. By magnetic resonance (MR) imaging, the lesion appeared as a low intensity lesion in T1-weighted images and a heterogeneous high intensity lesion with a low-signal radiation pattern on T2-weighted images. Gadolinium enhancement was observed partially within the lesion and intensely in the lesion rim. After curettage, histological examination revealed a massive accumulation of keratinous material with epithelial nests that displayed both epidermal and trichilemmal keratinization with basaloid and shadow cells and with metaplastic ossification. These features confirmed a pathological diagnosis of intraosseous counterpart of pilomatricoma. In the context of this patient’s skin lesions, intraosseous pilomatricoma may be a rare skeletal manifestation of Gardner syndrome. This case was presented at the 33rd Closed Meeting of the International Skeletal Society in Vancouver, September 2006.     

Computed tomography and magnetic resonance imaging evaluation of patellofemoral instability

Malalignment and tracking abnormalities of the patellofemoral joint are common causes of anterior knee pain,which are often difficult to evaluate clinically. Conventional radiography, as well as the cross-sectional imaging modalities of computed tomography (CT) and magnetic resonance imaging (MRI) are useful tools for both detecting and quantifying these abnormalities. Acute transient dislocation of the patella, on the other hand, is a relatively uncommon injury accounting for only 2% to 3% of all acute injuries of the knee, and can also be a difficult diagnosis to establish on the basis of history and physical findings alone. MRI is a sensitive, noninvasive method for detecting prior acute transient dislocation of the patella. This article begins by describing the role of CT and MRI as it pertains to the detection of abnormal patellofemoral tracking. Both static and dynamic techniques are described along with the standard criteria used to establish and quantify patellofemoral malalignment abnormalities. Next, the constellation of MRI findings most commonly encountered after acute transient dislocation of the patella are described. These findings include a typical bone bruise pattern involving the anterolateral aspect of the lateral femoral condyle and inferomedial patella, hemarthrosis, and injury to the medial soft-tissue restraints (especially the medial patellofemoral ligament). After transient dislocation of the patella, patients with significant osteochondral injury or disruption of the medial soft-tissue restraints may benefit from surgical repair. The role of MRI in preoperative planning is discussed as it relates to the detection of osteochondral injuries as well as injury to the medial soft-tissue restraints.     

Superior results with continuous passive motion compared to active motion after periosteal transplantation A retrospective study of human patella cartilage defect treatment

Fifty-seven consecutive patients (33 men and 24 women), with a mean age of 32 years (range 16–53 years), who suffered from an isolated full-thickness cartilage defect of the patella and disabling knee pain of long duration, were treated by autologous periosteal transplantation to the cartilage defect. The first 38 consecutive patients (group A) were postoperatively treated with continuous passive motion (CPM), and the next 19 consecutive patients (group B) were treated with active motion for the first 5 days postoperatively. In both groups, the initial regimens were followed by active motion, slowly progressive strength training, and slowly progressive weight bearing. In group A, after a mean follow-up of 51 months (range 33–92 months), 29 patients (76%) were graded as excellent or good, 7 patients (19%) were graded as fair, and 2 patients (5%) were graded as poor. In group B, after a mean follow-up of 21 months (range 14–28 months), 10 patients (53%) were graded as excellent or good, 6 patients (32%) were graded as fair, and 3 patients (15%) were graded as poor. Altogether, nine of the fair or poor cases (50%) were diagnosed with chondromalacia of the patella. Our results, after performing autologous periosteal transplantation in patients with full-thickness cartilage defects of the patella and disabling knee pain, are good if CPM is used postoperatively. The clinical results using active motion postoperatively are not acceptable, especially not in patients with chondromalacia of the patella. Received: 24 November 1998 Accepted: 30 January 1999     

Arthroscopic treatment of patients with moderate arthrofibrosis after total knee replacement

The purpose of this study was to document the effect of arthroscopic management in patients with knee stiffness after total knee replacement. We present a case series study, in which 32 patients have been treated for moderate arthrofibrosis of the knee after total knee replacement, with the same regimen. We have excluded all cases of stiffness, because of infection, mechanical mal-alignment, loosening of the implants and other obvious reasons of stiffness of the knee, rather than pure arthrofibrosis. All patients first underwent a trial of conservative treatment before going for arthroscopic management. A pain catheter for femoral nerve block was inserted just before anesthesia for post-operative pain management. Arthroscopic arthrolysis of the intra-articular pathology was performed in a standardized technique with release of all fibrous bands in the suprapatellar pouch, reestablishing the medial and lateral gutter, release of the patella, resection of the remaining meniscal tissue or an anterior cyclops, if needed. Intensive physiotherapy and continuous passive motion were to start immediately post-operatively. All the patients were available for the follow up and they were evaluated using the knee society rating system. A total of 25 of the 32 procedures resulted in an improvement of the patients knee score. All the knees operated upon had intra-articular fibrous bands, hypertrophic synovitis and peri-patellar adhesions. A total of eight patients suffered from an anterior cyclops lesion and six patients showed pseudomenicus. In 19 cases a medial and lateral relapse of the patella was performed; only 5 patients got an isolated lateral release. The mean knee flexion was 119° (100–130) at the end of arthroscopy and was 97° (75–115) at the last follow up. The eight patients with extension lags decreased from 27° (10°–35°) pre-operatively to 4° (0–10) at time of follow up. The average knee society ratings increased from 70 points prior to the arthroscopy to 86 at time of follow up, which was found to be statistically significant (P < 0.01, student’s t test). The average function score also showed improvement from 68 points pre-operatively to 85 at the time of final follow up. The average pain scores improved from 30 points pre-operatively to 41 at the time of final follow up. Our results showed that arthroscopic management of knee stiffness following total knee replacement is a safe and efficient method of treatment. Pain and functional knee scores can improve markedly.     

Misdiagnosis in sports medicine

With the increase in participation sports comes an increased prevalence of sports injuries. Injuries of the shoulder and knee present the sports medicine practitioner with the challenge of obtaining a proper diagnosis and providing appropriate treatment. Commonly misdiagnosed injuries to the shoulder and knee include anterior cruciate ligament injuries, patella subluxation/dislocation, and labral injuries. This article provides insight into obtaining a detailed history, performing a focused physical examination, and understanding the pathoanatomy of the affected joints in order to help avoid misdiagnosis of these complex injuries. These skills can aid practitioners to better meet the needs of the high school, college, professional, and recreational athlete.     

The coexistence of Osgood-Schlatter's disease with Sinding-Larsen-Johansson's disease. Case report in an adolescent soccer player

Osgood-Schlatter's disease and Sinding-Larsen-Johansson's diseases belong to the group of osteochondroses which is composed of disorders related to trauma or abnormal stress without evidence of osteonecrosis. They both affect adolescents more frequently when there is a history of participation in sport and their pathogenesis is related to a traumatically induced disruption that shows more easily when a rapid growth spurt is present. The coexistence of these two diseases in a young soccer player is reported. In this case the bone mineral content of every athlete of the team was determined and the bone density of the injured boy resulted lower the mean values of the group. The result suggests the possibility that transitory osteoporosis, connected with the rapid growth spurt that is typical in the adolescence, should be considered as one of the possible causes which contribute to the development of osteochondritic lesions.     

Epithelioid hemangioendothelioma of bone

 Neoplasms of bone can arise from any of the cellular elements that constitute osseous tissues. Although tumors of vascular origin are not uncommon, the vast majority are benign. A rare malignant vascular tumor – epithelioid hemangioendothelioma of bone – classifically affects young males and produces osteolytic lesions involving the cortex and cancellous bone of the lower extremities. We present a case with these findings, as well as such unusual findings as cervical spine instability and lesions affecting no fewer than 45 different bones. We conclude that epithelioid hemangioendo-thelioma should be investigated by skeletal survey because (1) osteolytic lesions involving more that 50% of the cortex present a serious risk for pathologic fracture and (2) the natural history of multicentric epithelioid hemangioendothelioma is more indolent than its solitary counterparts