The management of the painful bipartite patella: a systematic review

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.

Accessory fragment migration in a professional baseball player with bipartite patella: A case report

INTRODUCTION

Bipartite patella (BP) is usually recognized as an incidental radiographic finding. Therefore, no reports have observed the process of accessory fragment migration. We present the case of a professional baseball pitcher with significant migration of the fragment during follow-up.

PRESENTATION OF CASE

A 26-year-old man was diagnosed with symptomatic BP and underwent conservative therapy. Eleven months later, he was unable to play baseball because of gradually worsening knee pain without obvious trauma. On radiographs, the accessory fragment which had located at the superolateral pole 11 months earlier migrated posterolaterally. The diagnosis of Saupe's type III BP was established, and open excision of the accessory fragment was performed. Postoperatively, full-weight-bearing walking and range-of-motion exercises were started the day after surgery. Three months after surgery, he could pitch with all his power without pain.

DISCUSSION

Since our patient was a professional baseball right-handed pitcher who needed to step strongly on his left knee during pitching, strong traction force from the vastus lateralis was likely to have been repeatedly applied to the accessory fragment. It might lead to migration of the accessory fragment. The open excision of the accessory fragment was performed because the accessory fragment had migrated away from the patella body.

CONCLUSION

We report a case of professional baseball player with symptomatic BP, in which case the chronological migration of the accessory fragment was observed without obvious trauma. When the accessory fragment is identified without obvious trauma, one of the differential diseases could be a BP.

Symptomatic Bipartite Patella in Adults Treated With Open Excision: Outcomes and Management

Introduction

Bipartite patella affects about 2% of people. Most cases are asymptomatic; however, some develop anterior knee pain during a sporting activity or trauma. When conservative treatment fails, surgery can be considered. This study aims to report the outcomes of fragment excision with or without lateral release in adults with the symptomatic bipartite patella.

Methods

The study was approved by the College of Medicine IRB. A retrospective review was performed. Patients were excluded if aged < 18 or had prior knee surgery. Data collected included: age, gender, BMI, sports played, occupation, physical exam findings, Saupe classification, conservative and surgical treatment, advanced imaging used, duration of follow-up, Lysholm score and postoperative complications.

Results

Eight patients were studied. The average age was 28.4 years and BMI was 31.5. Sporting activities included hunting, swimming, soccer, golfing and softball. Occupations included office job, laborer, manufacturing plant worker and truck driver. All patients complained of anterior knee pain exacerbated by sports or work. All patients failed >6 months of conservative treatment. Saupe classification included seven types III (superolateral) and one type II (lateral). Surgical treatment included one open excision, six arthroscopic-assisted open excisions and one arthroscopic-assisted open excision with the lateral release. The duration of follow-up averaged 15 months. The average preoperative and postoperative Lysholm score was 75 and 93, respectively. One postoperative complication occurred.

Conclusions

Bipartite patella is an uncommon cause of anterior knee pain in adults. When pain persists despite conservative care, fragment excision of less than 12% of the whole patella with or without lateral release resulted in excellent outcomes in the majority of cases.

Outcomes of surgical treatment of symptomatic bipartite patella in teenage athletes

Bipartite patella affects about 2% of people. Most cases are asymptomatic; however, some develop anterior knee pain during sports. When conservative treatment fails, surgery can be considered. This study reports the outcomes of fragment excision with or without lateral release in teenage athletes with symptomatic bipartite patella. The study was approved by the College of Medicine Institutional Review Board. A retrospective review was performed. Patients were excluded if age >18 or had prior knee surgery. Data collected included age, gender, BMI, sports played, Saupe classification, conservative and surgical treatment, advanced imaging used, duration of follow-up, Lysholm Score and postoperative complications. Five teenage patients were studied. The average age was 15.6 years and BMI was 23. Sports played included basketball, football, track-and-field and soccer. All patients complained of anterior knee pain exacerbated by sports. All patients failed >6 months of conservative treatment. Saupe classification included four type III (superolateral) and one type II (lateral). Two patients had an MRI. Surgical treatment included two open excisions and three arthroscopic-assisted open excisions with lateral releases. The average Lysholm Score was 97. Postoperatively, all patients returned to presurgery sporting activity at an average of 9.8 weeks (range, 6-13 weeks). A 16-year-old male treated by open excision developed a postoperative wound infection. He was successfully treated with irrigation & debridement and antibiotics and returned to sports at 6 weeks. Symptomatic bipartite patella is an uncommon cause of anterior knee pain in adolescent athletes. When pain persists despite conservative care, fragment excision with or without lateral release resulted in excellent pain relief and return to full sporting activity in all cases.

Arthroscopic Management for Bipartite Patella: A Systematic Review

Background:

Bipartite patella is a rare congenital condition that becomes painful following direct trauma or an overuse injury. If it remains painful despite nonoperative treatment, surgery may be warranted. The current gold standard is open fragment excision or lateral release; however, arthroscopic management is also possible.

Purpose:

To investigate the safety and efficacy of arthroscopic treatment of painful bipartite patella.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

Using Medline and Embase, we systematically reviewed the literature as of March 8, 2020, using the subject headings “bipartite patella” and “arthroscopy” and related key terms. All levels of evidence involving human studies in English were included. Articles were excluded if only the abstract was published or the study was related to nonsurgical treatment or nonrelated diagnoses. Data related to journal/article information, demographic/clinical data, arthroscopic technique, length of follow-up, treatment outcomes, and complications were extracted.

Results:

Eleven articles with 43 patients were included in the review. Most patients (n = 34; 79%) underwent arthroscopic lateral release, while 16% (n = 7) had arthroscopic excision of the accessory fragment and 5% (n = 2) had arthroscopic excision and release. All patients except for one, who experienced postoperative trauma, were pain-free after arthroscopic treatment and were able to return to sports after a mean 2.6 months.

Conclusion:

This review demonstrated that arthroscopic management of painful bipartite patella is a safe and effective alternative to open surgical excision or release. However, all articles were case studies or small case series, owing to the rarity of the condition. In the future, higher-level studies comparing arthroscopic techniques and postoperative rehabilitation programs should be performed.

Quantitative assessment of the vascularity of the skeletally immature patella: a cadaveric study using MRI

PURPOSE

While predominant blood supply to the adult patella enters inferomedially, little is known about skeletally immature patellar perfusion. Improved knowledge of immature patella vascularity can further understanding of osteochondritis dissecans, dorsal defects of the patella and bipartite patella, and help ensure safe surgical approaches. We hypothesized that the immature patella would exhibit more uniform blood flow. The study purpose was to quantify immature patella regional perfusion in comparison with adults.

METHODS

Ten cadaveric knees were utilized (five immature, five mature). The superficial femoral artery was cannulated proximally. Signal enhancement increases were compared from pre- to post-contrast MRI to assess relative arterial contributions to patella regions (quadrants, anterior/posterior, superior/inferior, medial/lateral, and outer/inner).

RESULTS

Quantitative-MRI analysis revealed similar distribution of enhancement between the immature and mature patella. The inferior pole exhibited significantly higher arterial contribution versus superior pole in both immature and mature groups (p = 0.009; both groups), while the inferomedial quadrant had the highest arterial contribution of all quadrants in both groups. The superolateral quadrant demonstrated the lowest arterial contribution in the immature group and second lowest in the adult group. The patella outer periphery had significantly greater arterial contribution than the inner central region in both immature (p = 0.009) and mature (p = 0.009) groups.

CONCLUSION

Distribution of arterial contributions between the immature and mature patella was similar. Our results highlight the importance of inferior and inferomedial blood supply in both immature and mature patellas. These findings have implications for paediatric and adult patients; surgical damage to inferior patellar vessels should be avoided to prevent associated complications.

Arthroscopic Excision of Bipartite Patella

A bipartite patella usually presents as an incidental finding on radiographs because most cases are asymptomatic. However, some patients may present with pain and functional limitations. Conservative treatment is sufficient to resolve symptoms in most cases; however, a small minority of patients may require surgical management. Recent studies have reported excellent results with an arthroscopic approach. This Technical Note details our procedure for treating a symptomatic bipartite patella that has not resolved with conservative care.

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.

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.

Ultrasound and bone: a pictorial review

The assessment of bone mainly relies on standard radiographs, CT, MRI, and bone scintigraphy depending on the anatomic region complexity and clinical scenario. Ultrasound (US), due to different acoustic impedance between soft tissues and the bone cortex, only allows the evaluation of the bone surfaces. Nevertheless, US can be useful in the evaluation of several bone disorders affecting the limbs as a result of its tomographic capabilities and high definition. This pictorial review article summarises our clinical experience in adults and reviews the literature on US bone examination. We first present the US appearance of normal bone and the main congenital anatomic variations, after which we illustrate the US findings of a variety of bone disorders. Although US has limits in bone assessment, its analysis must be a part of every musculoskeletal US examination.

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.

Ultrasound-guided injection and the pie crust technique for the treatment of symptomatic bipartite patella

PURPOSE

This study aimed to investigate the results of a new treatment procedure (ultrasound-guided injection and the "pie crust" technique for lengthening of capsular tendon structures) for symptomatic bipartite patella.

METHODS

We retrospectively investigated patient outcomes following the treatment of symptomatic type III bipartite patella with our new technique. Fifteen knees in 14 boys (mean age, 13.0 ± 1.7 years) were included. The procedure involved the injection of 1% lidocaine (2 mL) and triamcinolone acetonide (5 mg) between the patella and fragment. We then punctured 10 sites from one skin puncture to extend lateral capsular tendon structures. The patients were clinically assessed using the Victorian Institute of Sports Assessment (VISA) score before and 1 week, 1 month, and 3 months after the procedure. Patients were also evaluated for complications.

RESULTS

The average VISA score was 45.7 ± 4.7 before treatment, 70.6 ± 7.3 at 1 week post-treatment, 84.4 ± 16.6 at 1 month post-treatment, and 88.6 ± 18.3 at 3 months post-treatment. The VISA score improvement from before the procedure to 1 week after the procedure was significant (P < 0.01). There were no complications in any of the patients, who returned to sports at a mean of 4.2 ± 2.1 weeks after the procedure. However, two patients (three knees) had poor results and could not return to action; thus, they underwent surgical treatment 4 months after the ultrasonographic procedure.

CONCLUSIONS

This novel method is a potential treatment option for the management of symptomatic bipartite patella in outpatient clinics.

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.

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.

Editorial Commentary: Got Evidence? What We Really Need Is an Algorithm for Treating Symptomatic Bipartite Patella

Bipartite patella is an uncommon but potentially troublesome problem for young athletes. Numerous uncontrolled retrospective studies have reported good results after various treatments. What is needed are studies that will guide workup and support treatment decisions based on the condition of the cartilage surfaces of the fragment, presence of pseudoarthrosis, and size and location of the fragment. To support decisions, we need prospective comparative studies, either randomized or, at least, prospective cohort studies that identify patients at the time of presentation, document key decision points, and follow patients to successful resolution of symptoms.

Evaluation and management of knee pain in young athletes: overuse injuries of the knee

Recurrent or chronic activity related knee pain is common in young athletes. Numerous intrinsic conditions affecting the knee can cause such pain. In addition, knee pain can be referred pain from low back, hip or pelvic pathology. The most common cause of knee pain in young athletes is patellofemoral pain syndrome, or more appropriately termed idiopathic anterior knee pain. Although, numerous anatomical and biomechanical factors have been postulated to contribute the knee pain in young athletes, the most common underlying reason is overuse injury. In this paper, we have reviewed selected conditions that case knee pain in athletes, including anterior knee pain syndrome, Osgood-Schlatter disease, Sinding-Larsen-Johanssen syndrome, juvenile osteochondritis dissecans (JOCD), bipartite patella, plica syndrome, and tendonitis around the knee.

Surgical Technique for Arthroscopic Resection of Painful Bipartite Patella

Bipartite patella (BP) is uncommon and is usually an incidental finding. Painful BP occurs rarely and is usually associated with post-traumatic anterior knee pain. When nonoperative treatment fails, fragment resection is indicated. A systematic review shows a potentially increased risk of complications with open surgery. The purpose of this Technical Note is to demonstrate a simple arthroscopic technique for treating painful BP through resection of the bone fragment.

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.