Bipartite patellae as a cause of disability in the athlete

Imaging of the Pediatric Knee

During normal development, imaging findings in the immature knee joint may mimic pathology or indicate transient sites of weakness, prone to injury. This article reviews the development of the knee joint, age- and maturation-dependent imaging considerations, and various developmental variants that can be encountered, subdivided into those that involve the tibiofemoral and patellofemoral compartments, soft tissues, and osseous components. The tibiofemoral compartment section reviews the focal periphyseal edema zone (FOPE), ossification variants of the femoral condyles, distal femoral metaphyseal cortical irregularity from periosteal traction, and the metaphyseal subperiosteal stripe, which should be distinguished from pathologic mimickers such as endochondral ossification dysfunction, osteochondritis dissecans (OCD), fibroosseous lesion, periosteal and subcortical pathologies. The patellofemoral compartment section includes a review of partite patella, dorsolateral defect, variant trochlear morphology, and maturation-dependent sites of transient weakness that are prone to injury from repetitive overuse (Sinding-Larsen-Johansson syndrome and Osgood-Schlatter disease) and avulsion fractures (patellar sleeve and tibial tubercle avulsions). Finally, soft tissue (discoid lateral meniscus, meniscal flounce, anterior cruciate ligament variants) and osseous components (meniscal ossicle, fabella, and cyamella) are reviewed.

Multipartite patella: A review of diagnostic techniques and management of the symptomatic patient

Multipartite patella is an anatomical variant classified by the fragmentation of the main patellar body. The cause of this variant is due to failure in fusion of the patellar ossification centers. It is commonly misdiagnosed as a fracture of the patella in clinical practice, leading to unnecessary treatment measures. The aim of this review is to provide an overview of the development and classification of this variation, diagnostic imaging techniques, and assess the optimal management technique for the symptomatic patient. Multiple radiographic methods are used to identify this variant, with recent studies highlighting high sensitivity rates for nonradiative methods (ultrasound). In terms of symptomatic management, accessory fragment excision and vastus lateralis release provide the greatest alleviation of symptoms, with screw fixation being less favorable.

Imaging of Anatomical Variants Around the Knee

Several anatomical variants have been described in the knee. These variants may involve intra- and extra-articular structures, such as menisci, ligaments, plicae, bony structures, muscles, and tendons. They have a variable prevalence, are generally asymptomatic, and are usually discovered incidentally in knee magnetic resonance imaging examinations. A thorough knowledge of these findings is essential to avoid overestimating and overinvestigating normal findings. This article reviews most anatomical variants around the knee, describing how to avoid misinterpretation.

Treatment of congenital bipartite patella in pediatric population - a systematic review of the published studies

Bipartite patella is an abnormality where patella is incorrectly ossified resulting in fibrocartilaginous synchondrosis. In most cases bipartite patella is asymptomatic and incidental finding but can also be painful especially in adolescents. The aim of our analysis was to determine the preferable treatment for pediatric bipartite patella. We conducted a systematic review based on PubMed and Embase searches. All original articles with reference to treatment in the population of ≤ 20 years of age, were included. Case reports, and articles without individualized data were excluded. In total, the individual data of 126 knees in 116 patients was analyzed. In 77.8% (98/126) of the analyzed knees the result was excellent, and the majority of the knees, 89.7% (105/126) received surgical intervention, and seven different techniques were used. None of operative methods were superior to others. Excellent treatment outcomes were achieved more often in younger patients (p=0.004), and the median duration of symptoms in operatively treated patients was shorter (p=0.018). If operative treatment is used after unsuccessful conservative treatment, it should be considered early in adolescence and also within a relatively short period after the onset of symptoms. The best operative method could not be found. More research and RCTs are needed concerning the conservative methods and different operative techniques.

Patella Fracture Identified Using Point-of-care Ultrasound

A 49-year-old female fell from standing. Her right knee extended into the air. She had acute right knee pain preventing weight-bearing. Her knee was most comfortable fully-extended. She could not flex it due to pain, nor extend it against resistance. Tenderness and a horizontal defect were noted over the anterior knee. Bedside ultrasound demonstrated a horizontally-fractured patella (confirmed on X-ray) with intact femoral and patellar tendons. She was put in a knee immobilizer and underwent surgery, with return to full function and activities. Ultrasound can identify patella fractures and help with early evaluation, management, and specialty referral, as well as ordering more-focused imaging. In one study, POCUS (point-of-care ultrasound) for patella fracture had 95% sensitivity, 63% specificity, 86% positive predictive value, and 83% negative predictive value. The dynamic nature of ultrasound allows a ruptured patella (87% sensitivity) or quadriceps tendon (100% sensitivity) to be excluded with high certainty.

Operative Treatment of Bipartite Patella in Pediatric and Adolescent Athletes: A Retrospective Comparison With a Nonoperatively Treated Cohort

Background:

Bipartite patella (BPP) is a developmental anomaly that forms when incomplete patellar ossification leaves a residual fibrocartilaginous synchondrosis between ossification centers. Repetitive traction forces across the synchondrosis can cause knee pain, most commonly presenting in adolescence. Symptoms frequently resolve with nonoperative management. Few surgical case series exist to guide treatment approaches for refractory pain.

Purpose:

To investigate the clinical features, surgical techniques, and outcomes associated with operative treatment of symptomatic BPP in pediatric and adolescent athletes and to compare features of the series with a large control group managed nonoperatively.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective medical record review was conducted of all patients aged ≤20 years who were diagnosed with symptomatic, radiologically confirmed BPP between 2003 and 2018 at a single tertiary-care pediatric hospital (N = 266). Demographic and clinical variables were analyzed, and additional radiologic and perioperative variables were collected for the surgical subcohort.

Results:

Of the 266 patients included, 27 were treated operatively (10.2%). When compared with those treated nonoperatively (with rest, physical therapy, cryotherapy, and anti-inflammatory medications), the operatively managed group experienced a longer duration of symptoms before first presentation (21.5 vs 7.6 months; P < .001) and were more likely to be older (mean age, 15.4 vs 12.4 years; P < .001), female (59.3% vs 35.6%; P = .03), and competitive athletes (100% vs 84.5%; P = .02). In the 27 patients treated operatively, procedures were categorized as isolated fragment excision (n = 9), fragment excision with lateral release (n = 8), isolated lateral release (n = 5), fragment screw fixation (n = 4), and synchondrosis drilling (n = 1). The mean time between surgery and return to sports was 2.2 months. Four patients (14.8%) reported residual symptoms requiring secondary surgery, including lateral release (n = 1), excision of residual fragment (n = 1), and fixation screw removal (n = 2).

Conclusion:

BPP can cause knee pain in adolescent athletes and is generally responsive to nonoperative treatment. Patients undergoing surgical treatment—most commonly female competitive athletes with prolonged symptoms—represented 10% of cases. A variety of surgical techniques may be effective, with a 15% risk of persistent or recurrent symptoms warranting reoperation. Prospective multicenter investigations are needed to identify optimal candidates for earlier interventions and the optimal operative treatment technique.

Magnetic resonance imaging for diagnosis of bipartite patella: usefulness and relationship with symptoms

Purpose

Bipartite patella is a rare developmental variation of the knee cap. We aimed to identify the magnetic resonance imaging (MRI) features of bipartite patella and evaluate the association with clinical symptoms.

Material and methods

MRI exams of 61 patients with bipartite variant were evaluated for types of bipartite patella, oedema around the synchondrosis, bipartite fragment height (FH), distance between the fragment and the patella (FPD), and signal characteristics within the synchondrosis. The study was designed with two observers in order to achieve intra- and interobserver compliance. Any other major knee pathologies that can cause pain were also recorded.

Results

Of the 61 participants the average age was 40.1 ± 14.3 years, 44 were males, and 17 were females. Fifty-nine of the bipartite fragments were located at the superolateral quadrant of the patella. There was oedema at the bipartite area in 35 patients. Ten of these patients had no major MRI diagnosis other than oedema, and they were classified as the symptomatic group. The age of the patients in the symptomatic group was statistically lower than in the asymptomatic group (p < 0.05). There was no statistically significant difference between the groups in terms of male and female distributions, signal types across the synchondrosis, and FH or FPD measurements (p > 0.05). High concordance correlation coefficients were observed on measurements.

Conclusions

MRI of the knee is highly accurate in evaluation of bipartite patella. To our knowledge; a detailed MRI analysis, like in our study, has not previously been performed, and our report is unique in showing that the symptomatic occurrence of bipartite patella is statistically higher in young patients.

Synchondrosis Bither Block: A New Addition in the Diagnosis of Symptomatic Bipartite Patella

Symptomatic bipartite patella is uncommon, and to ensure good outcome, patient selection is the key. Mostly assigning the pain origin to the nonfused fragment is easy though, in few cases, can be a serious dilemma, especially in the absence of direct tenderness over nonfused fragment. The decision of surgical intervention is solely made on the criteria of exclusion of other causes in the presence of persistent anterior knee pain. The literature focuses on different treatment techniques and outcomes with a rare attempt to add to the currently available supporting tests to affirmatively ascertain the cause-pain relation to the bipartite fragment. This article defines the synchondrosis block to assist the surgeon in isolating the source of pain to bipartite fragment in symptomatic knee.

Small but troublesome: accessory ossicles with clinical significance

Accessory ossicles are supernumerary and inconstant structures that are not caused by fractures. Derived from unfused ossification centers, accessory ossicles were first described by Vesalius in 1543. For centuries, they were believed to be asymptomatic. However, with advances in radiology techniques, many have been associated with painful syndromes. Although the original descriptions date from the sixteenth century, the subject is little discussed and, in some cases, controversial. The objective of this study was to describe the radiological aspects of a series of accessory ossicles and to review the evolution of their various descriptions, in order to revive discussion of the subject.

Clinical Outcome of Arthroscopic Lateral Retinacular Release for Symptomatic Bipartite Patella in Athletes

PURPOSE

To report the results of arthroscopic lateral retinacular release without excision of the accessory fragment for treatment of symptomatic bipartite patella with a minimum 2-year follow-up.

METHODS

We retrospectively reviewed all cases of symptomatic type III bipartite patella confirmed by radiographs, computed tomography, and magnetic resonance imaging and treated with arthroscopic lateral release from 2005 to 2015. Patients with history of knee fractures or surgery, concomitant meniscal or anterior cruciate ligament (ACL) procedures, and severe arthritic changes of the patellofemoral joint were excluded. Patients were assessed by Kujala score, visual analog scale (VAS), Tegner Activity Scale (TAS), and time to return to sporting activities.

RESULTS

Ten patients (11 knees) were clinically reassessed after 69.6 ± 33.3 (range: 25-132; 95% confidence interval [CI]: 47.29-91.99) months from surgery. There was a significant improvement in Kujala (P < .05) and VAS scores (P < .05), and no differences were found between pre- and postoperative TAS scores (P > .05). No complications occurred during the follow-up period. All patients returned to sport after 42.3 ± 11.3 (range: 30-60; 95% CI: 34.71-49.84) days after surgery.

CONCLUSIONS

The arthroscopic lateral retinacular release of a symptomatic type III bipartite patella without excision of the accessory fragment allowed early return to sporting activities, with excellent symptom relief. Patients had significantly improved mean Kujala and VAS scores without a decrease in the mean TAS scores.

LEVEL OF EVIDENCE

Level IV, case series.

Successful Treatment of Painful Synchondrosis of Bipartite Patella after Direct Trauma by Operative Fixation: A Series of Six Cases

Introduction:

The patella is the largest sesamoid bone in the body and may have one (77%) or multiple (23%) ossification centres. Patellar and patellofemoral joint abnormalities are a common cause of anterior knee pain but symptomatic bipartite patella is an uncommon problem.

Case Series:

We report a series of six cases of painful synchondrosis in bipartite patellae, all in keen athletes following a direct blow to the anterior aspect of the knee. A complete rupture of the synchondrosis with evidence of retropatellar chondral separation was seen on MRI scan in all cases. Successful surgical fixation was undertaken with complete resolution of symptoms in all patients at an average of three months post-operatively.

Conclusion:

Painful synchondrosis of a bipartite patella in young and active individuals following direct trauma is a relatively rare cause of anterior knee pain, but may be associated with significant morbidity. In cases refractory to non-operative management, successful symptomatic treatment can be achieved by operative fixation.

Forensic Identification of Bipartite Patella Misdiagnosed as Patella Fracture

Bipartite patella is recognized as a developmental anomaly of ossification. Most of them are asymptomatic and are discovered incidentally. Bipartite patella is sometimes misdiagnosed as a patella fracture, because the x-ray images of both these conditions may appear very similar. In this case, the patient complained of left knee pain after x-ray films revealed a fracture-like line in the left patella. The patient was then diagnosed as having a patella fracture. In China, the injury degree is categorized as serious injury, minor injury, and trivial injury. As the injury degree of patellar fracture is identified as minor injury, the defendant who injured the patient will be sentenced to prison for ≤3 years. However, the defendant objected to this judgment and applied for the second evaluation of injury degree. On the basis of the site of injury, clinical manifestations, and imaging findings, we diagnosed the patient with bipartite patella which belongs to normal anatomic variant. Therefore, the injury degree of the patient was not minor injury.

Arthroscopic treatment of painful Sinding-Larsen-Johansson syndrome in a professional handball player

Sinding-Larsen-Johansson (SLJ) syndrome is a type of osteochondrosis of the distal pole of the patella most often caused by repeated microtrauma. Here, we describe the case of a professional athlete with painful SLJ syndrome treated arthroscopically. A 29-year-old male professional handball player presented with anterior knee pain that persisted after 4 months of an eccentric rehabilitation protocol and platelet-rich plasma injections. Despite this conservative treatment, the patient could not participate in his sport. The SLJ lesion was excised arthroscopically, which led to complete disappearance of symptoms and return to competitive sports after 5 months.

The management of the painful bipartite patella: a systematic review

PURPOSE

This study aimed to identify the most effective method for the treatment of the symptomatic bipartite patella.

METHODS

A systematic review of the literature was completed, and all studies assessing the management of a bipartite patella were included. Owing to the paucity of randomised controlled trials, a narrative review of 22 studies was completed. A range of treatments were assessed: conservative measures, open and arthroscopic fixation or excision and soft tissue release and excision.

RESULTS

All of the methods provided results ranging from good to excellent, with acceptable complication rates.

CONCLUSIONS

This is a poorly answered treatment question. No firm guidance can be given as to the most appropriate method of treating the symptomatic bipartite patella. This study suggests that there are a number of effective treatments with acceptable complication rates and it may be that treatments that conserve the patella are more appropriate for larger fragments.

LEVEL OF EVIDENCE

IV.

Unique patellofemoral alignment in a patient with a symptomatic bipartite patella

BACKGROUND

A symptomatic bipartite patella is rarely seen in athletic adolescents or young adults in daily clinical practice. To date, only a limited number of studies have focused on patellofemoral alignment. The current study revealed a unique patellofemoral alignment in a patient with a symptomatic bipartite patella.

METHODS

Twelve patients with 12 symptomatic bipartite patellae who underwent arthroscopic vastus lateralis release (VLR) were investigated (10 males and two females, age: 15.7±4.4years). The radiographic data of contralateral intact and affected knees were reviewed retrospectively. From the lateral- and skyline-view imaging, the following parameters were measured: the congruence angle (CA), the lateral patellofemoral angle (LPA), and the Caton-Deschamps index (CDI). As an additional parameter, the bipartite fragment angle (BFA) was evaluated against the main part of the patella in the skyline view.

RESULTS

Compared with the contralateral side, the affected patellae were significantly medialized and laterally tilted (CA: P=0.019; LPA: P=0.016), although there was no significant difference in CDI (P=0.877). This patellar malalignment was found to significantly change after VLR (CA: P=0.001; LPA: P=0.003) and the patellar height was significantly lower than in the preoperative condition (P=0.016). In addition, the BFA significantly shifted to a higher degree after operation (P=0.001).

CONCLUSIONS

Patients with symptomatic bipartite patellae presented significantly medialized and laterally tilted patellae compared with the contralateral intact side. This malalignment was corrected by VLR, and the alignment of the bipartite fragment was also significantly changed.

LEVEL OF EVIDENCE

Level IV, case series.

Return to activity among athletes with a symptomatic bipartite patella: a systematic review

BACKGROUND

A bipartite patella is typically rare, but can become symptomatic during overuse activities such as those performed during athletic events. Therefore, this anomaly typically presents in the young, athletic population, often inhibiting athletic activities. Multiple treatment options exist, with nonsurgical management frequently adopted as the initial treatment of choice.

PURPOSE

To determine the most effective intervention in returning athletes with symptomatic bipartite patella to their prior activity levels.

METHODS

A systematic review of the literature was performed using PRISMA guidelines to identify studies reporting outcomes of athletes' ability to return to activity following treatment for a symptomatic bipartite patella. The type of intervention, type of bipartite classification, outcomes, and complications were recorded.

RESULTS

Twenty articles with a total of 125 patients and 130 knees were identified and included in this review. A total of 105 athletes made a full return to athletic activity following treatment for their painful bipartite patella. One hundred athletes (85.5%) that underwent surgical treatment were able to make a full return to their sport without symptoms, although this varied by surgical procedure performed. Excision of the painful fragment produced the best results in returning athletes to sport, with 91% returning without symptoms and nine percent returning but with residual symptoms.

CONCLUSION

Surgical treatments for symptomatic bipartite patellae are successful at returning athletes to their same level of play, and best outcomes are with excision of the fragment. These results are limited, however, due to the poor quality of original data given the rarity of the anomaly and the underrepresented conservative treatment group.

Bipartite patella causing knee pain in young adults: a report of 5 cases

We report on 5 patients who underwent arthroscopic excision or open reduction and internal fixation for bipartite patella. All patients presented with refractory anterior knee pain. The diagnosis of bipartite patella was made using radiography, and confirmed with magnetic resonance imaging or computed tomographic arthrography. All 5 patients achieved complete resolution of symptoms after surgery, and remained pain-free after a mean followup period of 13 months.

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.

Efficacy of surgical interventions for a bipartite patella

Bipartite patella is a relatively rare phenomenon. This anomaly is typically asymptomatic but can become painful with overuse, strenuous activities, or trauma, which is why it is typically seen in a young, athletic population. Although nonsurgical management is the initial treatment, if symptoms persist, surgical intervention may be necessary. Multiple surgical options exist, such as excision or fixation of the fragment or release of lateral soft tissue structures. The authors report the efficacy of various surgical interventions on a symptomatic bipartite patella, with outcomes related to symptom relief and ability to return to preoperative levels of activity. A systematic review was performed using multiple databases. Studies reporting outcomes of symptom relief or ability to return to activity following surgical intervention for a bipartite patella were included. Surgical technique, type of bipartite, and complications were recorded. Twenty-four articles with a total of 122 patients and 127 knees were included and reviewed. Relief of pain was achieved in 84.1% of patients, with 98.3% able to return to their preoperative activity levels after surgery. For patients with a symptomatic bipartite patella, return to preoperative activity levels with zero to minimal pain can be achieved with excellent results using any of the reported surgical methods.

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.

Arthroscopic treatment of symptomatic bipartite patella

Successful arthroscopic treatment of symptomatic bipartite patella in a 23-year-old female professional volleyball player is reported.

Magnetic resonance imaging of anatomical variations in the knee. Part 2: miscellaneous

Magnetic resonance imaging is the modality of choice for investigation of internal derangement of the knee. The reporting radiologist must be familiar with both normal anatomy and anatomical variants within the knee, in order to avoid mis-diagnosis, over-investigation and unnecessary intervention. This article reviews the recognised anatomical variants of the non-ligamentous/musculotendinous structures of the knee, their anatomy, incidence and typical appearances on MRI.

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.

Excision of painful bipartite patella: good long-term outcome in young adults

Excision of the accessory bipartite fragment is widely used, but its long-term outcome is not known. We evaluated the outcome after surgical excision of a symptomatic accessory bipartite or multipartite patella fragment in young adult men performing their compulsory military service and determined the incidence of painful bipartite patellae in this group of skeletally mature adults. We followed 25 of 32 patients for a minimum of 10 years (mean, 15 years; range, 10-22 years). The incidence of painful, surgically treated bipartite patella was 9.2 per 100,000 recruits. Patients' median age at surgery was 20 years. There were 19 superolateral and six lateral bipartite fragments. Other radiographic findings were rare. At followup, the Kujala score mean was 95 points (range, 75-100 points), and osteoarthrotic changes (Kellgren-Lawrence Grade 1) were seen in two knees. No reoperations related to bipartite patella occurred during the followup. Symptomatic bipartite patella is rare and does not seem primarily associated with anatomic deviations, but when incapacitating pain persists despite nonoperative treatment, surgical excision seems to yield reasonable functional outcome and quick recovery with no apparent adverse sequelae. Our data suggest there is no reason to avoid this technically undemanding procedure for treating persistent symptoms of bipartite patella in young adults.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Symptomatic bipartite patella: treatment alternatives

Bipartite patella is usually an asymptomatic, incidental finding. However, in adolescents, it may be a cause of anterior knee pain following trauma or a result of overuse or strenuous sports activity. Most patients improve with nonsurgical treatment. Surgery is considered when nonsurgical treatment fails. Excision of the fragment is the most popular surgical option, with good results. However, when the fragment is large and has an articular surface, excision may lead to patellofemoral incongruity. Lateral retinacular release and detachment of the vastus lateralis muscle insertion are other surgical options and are reported to produce good pain relief and union in some patients. These procedures reduce the traction force of the vastus lateralis on the loose fragment. Internal fixation of the separated fragment has limited support in the literature. Understanding the possible consequences of different treatment approaches to painful bipartite patella is necessary to preserve quadriceps muscle strength and patellofemoral joint function.

Bone union of painful bipartite patella after treatment with low-intensity pulsed ultrasound: report of two cases

We report two cases of painful bipartite patella in which bone union was achieved after treatment with low-intensity pulsed ultrasound. Both patients were 13-year-old males. Each received ultrasound (SAFHS, EXOGEN) for 20 min a day. The interval between the onset of pain and ultrasound treatment was between 2 and 4 months. The patellar pain disappeared within two months after treatment in both cases. Bone union was seen radiographically at 4 months. Low-intensity pulsed ultrasound is a non-invasive treatment that appeared to be helpful in the management of two patients with painful bipartite patella.

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.

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.

Tripartite patella: late appearance of a third ossification center in childhood

Bilateral radiographic progression of the supero-lateral fragment of a bipartite- into a tripartite patella with unilateral symptoms. An 8 year old girl presented a bilateral bipartite patella Stage III as an incidental finding after fall on the flexed right knee. Serial radiographs two years later revealed a bilateral progression of the bipartite- into a tripartite patella with complaints only on the post-traumatic right side. Observation was opted as therapy. There was no correlation of symptoms and radiological findings of the fragmentation of the bipartite- into a tripartite patella. Therefore we conclude the etiology of a bilateral late appearance of a third ossification center.

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.

Knee fractures in the athlete

Sports-related fractures of the knee, although uncommon, do occur during athletic participation. The assessment and management of each fracture type have been emphasized in this article to provide a guideline for treating these acute knee injuries to a successful return to sports-specific competition. Anatomic fracture reduction is necessary to have optimal joint function in the knee as well as stability of fracture for early joint motion, promote bone healing, and avoid traumatic arthritis. This is especially crucial to the injured athlete, as residual deficits of the knee can greatly affect performance. Selection of low-profile implants at the time of surgery to prevent soft tissue irritation and possible implant removal must also be considered with the return to athletic activity.

Vastus lateralis release for painful bipartite patella

PURPOSE

The purpose of this study was to evaluate the efficacy of vastus lateralis release for painful bipartite patella. We have also compared the results of open method versus arthroscopic method using a holmium:YAG laser system (OmniPulse Holmium Laser System; Trimedyne Inc, Irvine, CA).

TYPE OF STUDY

This study was a nonrandomized control and cross-over trial.

METHODS

Fifteen patients with 17 painful bipartite patella who underwent vastus lateralis release were included in this study. The average age of patients was 14.3 +/- 2.2 years. In 7 knees of 6 patients, vastus lateralis release was performed through a skin incision over the bipartite fragment, and in 10 knees of 9 patients, we performed the procedure arthroscopically with the holmium:YAG laser. We assessed clinical and radiographic data of the patients chronologically in both groups.

RESULTS

In all patients, pain over the fragment disappeared within 4 weeks after the operation, and all returned to their previous sports activities at an average of 3.1 +/- 0.9 months postoperatively. Clinical assessment was classified as excellent in 13 knees and good in 4 knees. Bone union at 6 months after the operation was complete in 11 knees (64.7%) and incomplete in 6 knees (35.3%), and none of the knees was graded as not healed. Bone union in patients with an age of 15 or younger was significantly better than that in patients over 15 years of age (P <.05). Release under arthroscopy showed statistically better results in duration of knee effusion (P <.05), return of circumference of thigh (P <.05), and return of muscle strength (P <.05).

CONCLUSIONS

Because vastus lateralis release is less invasive surgery with good results, we conclude that this procedure can be a first choice of operative treatment for painful bipartite patella.

Bone-scintigraphy in painful bipartite patella

We report the scintigraphic-appearances of painful bipartite patella in 25-year-old man a 2 1/2 years history of unexplained patellar pain. Painful bipartite patella is a rare cause of chronic post-traumatic patellar pain. Bone scintigraphy, by demonstrating increased uptake by the painful accessory bipartite fragment, appears to be an imaging method of choice in the diagnosis of this condition.

Painful bipartite patella following injury

We report nine rare cases of painful bipartite patella following injury to the knee, in seven non-athletic adults. Patients suffered with persistent anterior knee pain and localized tenderness over the superolateral aspect of the patella for an average of 2 years following injury. The clinical, radiographic and arthroscopic findings are described. Excision of the accessory bipartite fragment resulted in satisfactory relief of pain and complete restoration of the knee function in all patients at a mean follow-up of 10 months (range 3-36 months). Although painful bipartite patella may be considered rare it should be recognized as a cause of post-traumatic anterior pain in the adult.

Efficacy of lateral retinacular release for painful bipartite patella

We treated painful bipartite patella with a modified lateral retinacular release technique in 15 patients (16 knees). Bony union of the separated fragment and the patella was obtained in 15 of 16 knees within 8 months of surgery. Sustained traction acting on the patella laterally and proximally is presumed to cause the pain. The surgical technique to reduce this force proved effective not only in relieving the pain but also in achieving bony union. Painful bipartite patella can lead to excessive lateral pressure syndrome or patellar compression syndrome, these complications can be effectively treated by this surgical technique. In contrast to conventional treatments, such as excision of smaller fragments or osteosynthesis to achieve bony union, the modified lateral retinacular release technique is easy to perform and provides an effective means for relieving patellofemoral pain and achieving bony union.

Painful bipartite patella. A new approach to operative treatment

Thirteen patients who had fifteen painful bipartite patellae were managed with a new operative technique in which the vastus lateralis insertion to the painful patellar fragment is detached subperiosteally while the continuity of the tendon-periosteum complex to the main portion of the patella is preserved. A grossly mobile patellar fragment was removed from five patellae (three type-II and two type-III according to the classification of Saupe). A fragment that showed minimum mobility was left in situ in seven type-III and three type-II patellae. All of the patients had prompt relief of the pain and returned to full sports activity within two months after the operation. Six of the seven type-III fragments that had not been removed united by bone to the main portion of the patella within two years postoperatively, but all three type-II fragments failed to unite. Over-all, eleven patients (thirteen knees) had an excellent result at an average of five years postoperatively.

Chronic Knee Pain in Active Adolescents Don't Forget the Uncommon Causes

In brief Chronic knee pain among active brief adolescents may be caused by a wide spectrum of conditions that range from generally benign, self-limited disorders, such as Osgood-Schlatter disease, to malignant osteosarcoma. Benign disorders account for the majority of knee pain in the adolescent athlete, and most causes are readily diagnosed. However, recognizing and treating the less common-often more serious-causes of chronic knee pain may be a greater challenge.

Overuse Knee Injuries in Young Athletes

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.

Stress fracture of the patella

Stress fractures are rarely an indication for surgical treatment. In our case we decided to operate on the patient because of distraction of the fragments. Solid bony healing took longer than in traumatic fractures, but the good functional result confirmed our regimen.