Traumatic separation of a bipartite patella

New variant of bipartite patella with traumatic separation and complete disruption of the extensor mechanism of the knee

Very few case reports have been reported on traumatic separation of the bipartite patella along with quadriceps tendon rupture. These reports relate to separation of superolateral bipartite patella (Saupe type 3). We describe a new variant which to our knowledge has not been described or classified so far, which is purely a superior bipartite patella with traumatic separation and complete functional disruption of the extensor mechanism of the knee in a young patient working in the army which was managed with open reduction and internal fixation along with repair of the extensor mechanism of the knee achieving complete functional recovery.

Bipartite patella separation and partial quadriceps tendon rupture in the setting of trauma

Normal development of the patella typically involves fusion of secondary ossification centers into a single bone during adolescence, with failure of fusion resulting in bipartite and tripartite patellae. In such variants, injury to incomplete ossification center fusion, though uncommon, has been reported to occur in the setting of traumatic quadriceps tendon rupture. The authors present a rare and complex case of traumatic bipartite fragment separation, patellar avulsion, and a complex partial quadriceps tendon tear confirmed surgically in a 36-year-old male. In this case, a tear in the lateral aspect of the quadriceps tendon attached to the nonfused patellar ossification center resulted in retraction of the band containing the bipartite fragment and separation of the patellar fragments, with superior displacement of the smaller bony avulsion likely due to complex attachments from the medial aspect of the quadriceps tendon. Knowledge of the classical locations of a bipartite and tripartite patella can aid in the differentiation of the anatomic variant versus patellar avulsion. Additionally, knowledge of the variable and complex nature of the quadriceps tendon aids in understanding the process of patellar avulsions and various tears, leading to the appropriate orthopedic management.

Traumatic Rupture of an Intermediate Tendon in a Patient with Patellar Duplication

Patellar duplication is a rare asymptomatic condition. The diagnosis is often made following a traumatic event associated with an injury to the knee extensor mechanism. The treatment is often surgical and consists in removal of the smaller part of the patella with tendon reinsertion. The presence and rupture of an intermediate tendon between the two parts of the patella have not been reported in the modern literature. We present a traumatic rupture of an intermediate tendon in a patient with horizontal patellar duplication. The surgical management consisted of tenorrhaphy protected with a figure-of-eight tension band wire approximating the two parts of the patella. The patient recovered full knee range of motion and quadriceps strength at the last 8-month follow-up.

Developmental anomaly of ossification type patella partita

PURPOSE

Bipartite patella has been recognized as an incidental radiographic finding. However, symptomatic bipartite patella is occasionally diagnosed in adolescents and young athletes. The incidence of bipartite patella has been reported at 0.2-1.7, and 1-2 % of these cases are symptomatic. The purpose of this review article was to discuss current concepts relevant to developmental anomaly of ossification type patella partita.

METHODS

A PubMed database search using the key words "bipartite patella" was performed. Clinical papers reporting the bipartite patella were included. Four German-language studies were also included, three for incidence of bipartite patella and one for classification.

RESULTS

A new classification of developmental anomaly of ossification type patella partita based on location and number of fragment was recently proposed. It is simple and useful and applicable to all types of bipartite or tripartite patella. Several imaging studies have reportedly been used to evaluate symptomatic bipartite patella. MRI is currently the most appropriate method used to assess patients with bipartite patella. Although surgical procedures have been developed that reduce excessive traction force by the vastus lateralis muscle on the bipartite fragment, there is not sufficient evidence to support their use for routine treatment of painful bipartite patella.

CONCLUSION

In most symptomatic cases, movement at the interface between the bipartite fragment and the body of the patella presumably causes the pain. Therefore, the existence of apparent motion at the interface should be confirmed by specific imaging studies before surgery. Magnetic resonance imaging findings may provide such evidence by demonstrating a fluid bright signal across the segmentation, typical of pseudoarthrosis.

LEVEL OF EVIDENCE

V.

Evaluating anterior knee pain

Musculoskeletal complaints account for about 20% to 30% of all primary care office visits; of these visits, discomfort in the knee, shoulder, and back are the most prevalent musculoskeletal symptoms. Having pain or dysfunction in the front part of the knee is a common presentation and reason for a patient to see a health care provider. There are a number of pathophysiological etiologies to anterior knee pain. This article describes some of the common and less common causes, and includes sections on diagnosis and treatment for each condition as well as key points.

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.

Separation of a bipartite patella combined with quadriceps tendon rupture: a case report

Separation of a bipartite patella is very rare. We found only seven cases in the literature [Carter SR. Traumatic separation of a bipartite patella. Injury 1989;20:244; Ireland ML, Chang JL. Acute fracture bipartite patella; case report and literature review. Med Sci Sports Exerc 1995; 27:299-302; Ishii M, Yabuno K, Ishikawa T, Tsujino H, Yamaguchi K. A case of bipartite patella separation accompanied by subcutaneous rupture of quadriceps tendon. Seikeigeka (Orthopedic Surgery) 2003;54:1563-5. [In Japanese]; Canizares GH, Selesnick FH. Bipartite patella fracture. Arthroscopy 2003;19:215-7; Okuno H, Sugita T, Kawamata T, Ohnuma M, Yamada N, Yoshizumi Y. Traumatic separation of a type 1 bipartite patella; a report of four knees. Clin Orthop 2004;420:257-60]. Among these cases only one was complicated with quadriceps tendon rupture, and the patient had diabetes as underlying disease [Ishii M, Yabuno K, Ishikawa T, Tsujino H, Yamaguchi K. A case of bipartite patella separation accompanied by subcutaneous rupture of quadriceps tendon. Seikeigeka (Orthopedic Surgery) 2003;54:1563-5. [In Japanese]]. To our knowledge, there have been no reports of this condition in a healthy subject. In this report, we present a case of bipartite patella separation complicated with quadriceps tendon rupture in a patient with no underlying disease. Treatment involving suturing the tendon to the patella and osteosynthesis of the bipartite patella produced a good result.

Bone scintigraphy in patients with bipartite patella

This study was performed to assess the diagnostic value of bone scintigraphy to differentiate symptomatic bipartite patella from asymptomatic bipartite patella. Thirty-seven bipartite patellae (15 symptomatic and 22 asymptomatic) were evaluated by bone scintigraphy. Bone scintigraphic activity in bipartite patella was classified into the following four groups. Group A: Eleven bipartite patellae (10 symptomatic and 1 asymptomatic) demonstrated physiological and marked uptake at the epiphysio-metaphysial junction of the distal femur in bone scintiscans. Therefore, high scintigraphic uptake in the bipartite patella was difficult to distinguish from such uptake due to overlap. Group B: Five bipartite patellae (4 symptomatic and 1 asymptomatic) demonstrated both physiologically high scintigraphic uptake at the epiphysio-metaphysial junction of the distal femur and high scintigraphic uptake in the bipartite patella. Group C: Seventeen bipartite patellae (1 symptomatic and 16 asymptomatic) demonstrated abnormally high scintigraphic uptake in the bipartite patella. Group D: Four asymptomatic bipartite patellae did not demonstrate an abnormally high scintigraphic uptake. After excluding Group A, the proportion of positive bone scans in bipartite patella was 84.6% (22 of 26 patellae). Similarly, after excluding Group A, the proportion of positive bone scans in symptomatic bipartite patella was 100% (5 of 5 patellae) and in asymptomatic bipartite patella 81.0% (17 of 21 patellae). Statistical analysis using Fisher's exact test showed no significant differences in the proportion of positive bone scans between both groups (P = 0.5457). In conclusion, abnormally high scintigraphic uptake is frequent findings in both symptomatic and asymptomatic bipartite patella, and bone scintigraphy is not useful to differentiate between them. Therefore, surgical treatment should not be considered based only on scintigraphic findings.

Partielle Quadrizepssehnenruptur bei einem sechsjährigen Jungen

In children, avulsion fractures of the patella are observed more frequently than ruptures of the quadriceps tendon. In cases of suspected lesions of the quadriceps tendon, conventional x-ray imaging and ultrasound comparison of both patellae is recommended. Arthroscopy is helpful for diagnosing concomitant intra-articular knee lesions and permits evacuation of the hemarthrosis.

Traumatic separation of an uncommon bipartite patella type: a case report

The authors report about a case of traumatic separation of a horizontally bipartite patella in a young female soccer player. Unspecific anterior knee pain preceded the fracture, which had occurred after an inadequate trauma. Open reduction and osteosynthesis led to bony union with an excellent clinical outcome at follow-up.

Hemilaterally symptomatic bipartite patella associated with bone erosions arising from a gouty tophus: a case report

Symptomatic bipartite patella in adults is rare. We have treated an unusual case of a bipartite patella in an adult, which became symptomatic in association with cystic degeneration localized to the patella and a gouty tophus. Although the patient had bilateral bipartite patellae, multiplanar reformation with computed tomography (CT-MPR) clearly demonstrated that the bipartite portion of the patella was malaligned at the junction of the accessory bone and patella in the symptomatic knee. Bone erosions were present both in the bipartite fragment and adjacent portion of the patella. After surgical excision of the bipartite fragment, the patient's symptoms have improved. This case illustrates that cyst formation associated with inflammatory arthritis may be a rare cause for a bipartite patella in an adult to become symptomatic.

Histopathological abnormalities in painful bipartite patellae in adolescents

The purpose of this study was to clarify the etiology of painful bipartite patella in adolescents by histopathological examination of excised specimens. We performed excision of a fragment of painful bipartite or tripartite patella from six patients (six knees). The articular cartilage, interposed tissue, bone, and bone marrow of the excised specimens were histologically examined. The articular cartilage was intact in all but two patellae. The predominant composition of the interposed tissue was fibrous tissue in one patient; fibrous tissue and fibrocartilage in four patients; and fibrous tissue, fibrocartilage, and hyaline cartilage in one patient. In the interposed tissue, diffuse degenerative and necrotic fibrocartilage was observed in four patients and focal necrotic fibrocartilage was seen in two patients. In all patients, the central region of the interposed tissue almost completely lacked blood vessels. Other histological features of the interposed tissue included necrosis of the trabecular bone in three patients, irregularly shaped spicules of immature bone in three patients, and fragments of hyaline cartilage in two patients. In all patients the bone marrow adjacent to the interposed tissue showed numerous small blood vessels, and trabecular bone surfaces and the fibrocartilage surface adjacent to this bone marrow was scalloped and lined with numerous osteoclasts. The striking histopathological features of the interposed tissue were fibrous tissue and necrosis of the fibrocartilage. These abnormalities may ultimately lead to the failure of an accessory ossification center to unite with the main portion of the patella.

Traumatic separation of a type I bipartite patella: a report of four knees

Four knees in three patients with traumatic separation of a Type I bipartite patella are reported. Sudden anterior knee pain and an audible pop occurred at the time of the injury and the patients had aching or dull pain before the traumatic episode. Previous aching or dull pain led us to differentiate this type of injury from a usual transverse fracture. A round fracture line seen on the radiographs also led us to differentiate this type of injury from a stress fracture. Accordingly, the diagnosis of a traumatic separation of a Type I bipartite patella was confirmed. This is the first report of a traumatic separation of a Type I bipartite patella to our knowledge.

Bipartite patella fracture

Bipartite patella fracture is an uncommon injury that has rarely been described in the literature. It can be quite debilitating in the competitive athlete and is often overlooked by the treating physician. A bone scan can be helpful in confirming the diagnosis, and appropriate treatment often results in a successful outcome.