Magnetic resonance arthrography with positional manoeuvre for the diagnosis of synovial fold of posterior shoulder joint capsule

OBJECTIVES

The objective of this study is to prospectively assess the effectiveness of shoulder magnetic resonance (MR) arthrograms with positional manoeuvres in detecting posterior synovial folds.

METHODS

Two radiologists independently assessed all axial MR arthrograms in internal rotation, neutral position, and external rotation for the presence of a posterior synovial fold. The diagnostic performances of the MR arthrograms were then compared, with results validated through arthroscopy.

RESULTS

Arthroscopy was performed on 81 of the 150 patients included in the study. A posterior synovial fold was identified arthroscopically in eleven of these patients. Measurements of the posterior synovial fold obtained in external rotation and the neutral position of the arm showed a significant correlation with arthroscopic results (p < 0.05). For detecting the posterior synovial fold with arthroscopic correlation, the sensitivity and specificity values for observer 1 and observer 2 were 100-81.4% and 100-88.6%, respectively, for MR arthrograms in the neutral position; 100-52.9% and 100-62.9% for MR arthrograms in external rotation; and 100-95.7% and 81.8-98.6% for MR arthrograms in internal rotation. There was a fair agreement for MR arthrography in external rotation for detecting posterior synovial folds, while MR arthrograms in internal rotation and neutral position showed near-perfect and significant interobserver agreement.

CONCLUSION

The rotational positions of the humeral neck during MR arthrographic examination can influence the diagnostic specificity and sensitivity of axial MR arthrograms in detecting the posterior synovial fold.

CLINICAL RELEVANCE STATEMENT

The posterior synovial fold can mimic a posterior labral detachment. Therefore, its correct identification is crucial in order to avoid unnecessary surgical procedures.

KEY POINTS

Movement of the shoulder may introduce variability in MR arthrography appearance. Rotation of the humeral neck during MR arthrography can affect diagnoses in posterior synovial fold detection. Given that posterior synovial folds can imitate posterior labral detachment, their correct identification is crucial to avoid unnecessary surgical procedures.

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

[MRI or ultrasound-which imaging technique do we need?]

Diagnostic imaging of epicondylitis is primarily performed using widely available, radiation-free ultrasound. The dynamic examination allows a rapid point-of-care assessment. Typical imaging findings of epicondylitis include intratendinous hypoechogenic foci at the humeral origin, ossification at the enthesis, intratendinous calcifications, or (partial) rupture. In particular, Doppler sonography increases sensitivity by assessing possible neovascularization within the tendon. When sonographic findings are unclear or extensive, or when ultrasound machines or the required expertise in elbow examinations are not available, magnetic resonance imaging is indicated. Here, the use of proton density-weighted sequences is appropriate for assessing bone marrow and soft tissue edema and tendon tears, while ossifications are best delineated in T1weighted sequences. Projection radiography and computed tomography can be helpful for larger ossifications, although they are not part of the standard imaging protocol.

Imaging of Anatomical Variants Around the Elbow

The elbow is a synovial joint able to perform flexion, extension, supination, and pronation. Knowledge of anatomical variants is crucial to avoid misinterpretation during the evaluation of the elbow joint. We address those anatomical variants simulating pathologic conditions.

Synovial plica of the elbow - detailed measurements and how to implicate its relevance in clinical practice

PURPOSE

The synovial plica of the elbow is a fold of synovial tissue, which is said to be a remnant of the embryonic septa of normal articular development and is located around the radiocapitellar joint. The objective of the present study was to provide morphometric properties of the synovial plica of the elbow and its relation to surrounding structures in asymptomatic patients.

METHODS

A retrospective study was conducted to establish the morphometric characteristics of the synovial plica of the elbow. The results of 216 consecutive patients, who for different reasons during the five year period of time underwent magnetic resonance imaging (MRI) of an elbow, were analyzed.

RESULTS

Plica was found in a total of 161 of 216 elbows (74.5%). The mean width of the plica was set to be 3.00 mm (SD: 1.39). The mean length of the plica was established at 2.91 mm (SD: 1.13). An analysis of sexual dimorphism was also included. Potential correlations were analyzed for each of the categories and age.

CONCLUSIONS

The synovial plica of the elbow is a clinically relevant anatomical structure. Analyzing the morphometric parameters of the synovial plica is necessary to properly evaluate synovial plica syndrome, which can commonly be confused with other sources of lateral elbow pain such as tennis elbow, oppression of the radial and/or posterior interosseous nerve, or snapping of the triceps tendon. The authors suggest that the thickness of the plica may not be the golden diagnostic feature as there are no statistically significant differences in this parameter between symptomatic and asymptomatic patients. A precise and accurate diagnosis of synovial fold syndrome and/or differentiation from other sources of lateral elbow pain must be performed, as the surgical treatment, even if performed properly, will be unsuccessful because of a misdiagnosed source of pain.

Arthroscopic lateral collateral ligament imbrication for treatment of atraumatic posterolateral rotatory instability

BACKGROUND

Among the causative lesions of lateral elbow pain, atraumatic posterolateral rotatory instability (PLRI) is a rare condition, but it produces pain and disability to the elbow. It still lacks published specific treatment literature. According to the development of arthroscopy, the arthroscopic lateral collateral ligament (LCL) imbrication can possibly be an alternative minimal invasive procedure that can eradicate the atraumatic PLRI. Hypothesis/Purpose: To report clinical results of arthroscopic LCL imbrication for the treatment on atraumatic PLRI elbow. Methods: Thirty-three patients with chronic atraumatic lateral elbow pain were presented to our institution between July 2015 and December 2021. Eight patients were diagnosed with atraumatic PLRI and underwent arthroscopic LCL imbrication. Comparison between the pre- and post-operative scores were recorded, which were The Quick-Disabilities of Arm, Shoulder, and Hand (Quick-DASH) score, Mayo Elbow Performance Index (MEPI) and Visual Analog Scale for pain (VAS). Results: Mean follow-up was 16 months (9-24 months). Comparing between pre-operation and post-operation, all of eight patients had significant improved Quick-DASH score (mean 55.62 vs 7.62, p = .004), MEPI (mean 50.00 vs 96.87, p = .000) and VAS for pain (mean 8.14 vs 1.28, p = .000). Conclusion: Atraumatic PLRI is a concerning lesion in patients with lateral elbow pain. Arthroscopic LCL imbrication can be simultaneously performed with other lateral elbow pain causations, such as tennis elbow and pathological plica, and provide painless, stable, and functional elbow.

LEVEL OF EVIDENCE

Case Series (Level of evidence: 4).

Tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis: Results of 2 years of follow-up

Hypothesis

We hypothesized that the treatment of recalcitrant lateral epicondylitis requires accurate identification of the painful area to promote remodeling of the degenerated extensor insertion and to stabilize the tendon origin during tendon healing. Thus, we performed tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis.

Methods

Twenty patients (21 elbows) were treated with bone marrow venting at the painful area of the lateral epicondyle of the elbow and tenodesis using 2 soft anchors lateral to the capitellum (immediately distal to the painful area) and were followed up for ≥2 years. Patients were assessed using the numerical rating scale for pain and the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire, and objective evaluation included active range of motion.

Results

The mean preoperative and postoperative pain scores were 7.5 and 0.5, respectively, indicating significant pain relief (P < .001). The mean preoperative and postoperative Quick Disabilities of the Arm, Shoulder, and Hand questionnaire scores were 44.2 and 1.0, respectively (P < .001). Two elbows had a slightly positive Thomsen test at the final visit. No recurrence of intra-articular symptoms induced by synovial fringe impingement was observed. Patients experienced more pain at the bone-tendon junction of extensors than at the tendon parenchyma.

Conclusion

Tenodesis with bone marrow venting under local anesthesia was effective for subjective patient satisfaction and positive clinical outcomes at ≥2 years of follow-up in patients with recalcitrant lateral epicondylitis. Intra-articular symptoms can be improved by stabilization of the lateral soft tissue without treatment for intra-articular lesions.

Overuse Elbow Injuries in Youth Gymnasts

BACKGROUND

Gymnastics is a unique sport that places significant loads across the growing elbow, resulting in unique overuse injuries, some of which are poorly described in the current literature.

PURPOSE

To provide a comprehensive review of the unique overuse elbow injuries seen in youth gymnasts and to provide an up-to-date synthesis of the available literature and clinical expertise guiding treatment decisions in this population.

STUDY DESIGN

Narrative review.

METHODS

A review of the PubMed database was performed to include all studies describing elbow biomechanics during gymnastics, clinical entities of the elbow in gymnasts, and outcomes of operative and/or nonoperative treatment of elbow pathology in gymnasts.

RESULTS

Participation in gymnastics among youth athletes is high, being the sixth most common sport in children. Early specialization is the norm in this sport, and gymnastics also has the highest number of participation hours of all youth sports. As a result, unique overuse elbow injuries are common, primarily on the lateral side of the elbow. Beyond common diagnoses of radiocapitellar plica and osteochondritis dissecans of the capitellum, we describe a pathology unique to gymnasts involving stress fracture of the radial head. Additionally, we synthesized our clinical experience and expertise in gymnastics to provide a sport-specific rehabilitation program that can be used by providers treating surgical and nonsurgical conditions of the elbow and wishing to provide detailed activity instructions to their athletes.

CONCLUSION

Overuse injuries of the elbow are common in gymnastics and include osteochondritis dissecans of the capitellum, radiocapitellar plica syndrome, and newly described radial head stress fractures. A thorough understanding of the psychological, cultural, and biomechanical aspects of gymnastics are necessary to care for these athletes.

Imaging of Elbow Injuries

Familiarity with throwing mechanics during elbow range of motion allows accurate diagnosis of sports-related elbow injuries, which occur in predictable patterns. In addition, repetitive stress-related injuries are often clinically apparent; however, imaging plays an important role in determining severity as well as associated injuries that may affect clinical management. A detailed understanding of elbow imaging regarding anatomy and mechanism of injury results in prompt and precise treatment.

Common tendinopathies around the elbow; what does current evidence say?

Tendinopathies are common causes of pain around the elbow resulting in significant functional impairment in athletes or the working-age population. Patients complain of a gradual onset pain with or without any specific trauma. Tissue histology shows chronic fibroblast and vascular proliferation, with a disorganized collagen pattern and absence of inflammatory mediators. Currently, numerous treatment options are described, but many of these are only supported by a heterogenous evidence base. Thus, management guidelines are difficult to define. Surgery is mostly indicated in selected cases that have failed non-operative management. This article reviews the pathophysiology and natural history of lateral and medial elbow tendinopathies, as well as distal biceps and triceps tendinopathies, and their current treatment options.

Synovial plica of the elbow and its clinical relevance

A synovial plica (fold) is normal anatomic finding, and occurs in 86–100% of cases; however, symptomatic plica is much less common (7.2–8.7% of all elbow arthroscopies).

Synovial plica syndrome is a painful elbow condition related to symptomatic synovial plica.

Synovial plica syndrome is diagnosed by clinical examination (lateral elbow pain) commonly accompanied by local tenderness, pain at terminal extension and/or painful snapping.

Synovial plica syndrome may be mimicked by other elbow conditions, commonly tennis elbow, loose bodies, and degenerative arthritis.

Magnetic resonance imaging or ultrasound scan may support diagnosis in correlation with clinical findings, but symptomatic plica may also be diagnosed as unexpected during elbow arthroscopy.

The arthroscopic resection is effective and safe if conservative treatment fails.

Cite this article: EFORT Open Rev 2020;5:549-557. DOI: 10.1302/2058-5241.5.200027

Magnetic resonance imaging of the elbow

Elbow pain can cause disability, especially in athletes, and is a common clinical complaint for both the general practitioner and the orthopaedic surgeon. Magnetic resonance imaging (MRI) is an excellent tool for the evaluation of joint pathology due to its high sensitivity as a result of high contrast resolution for soft tissues. This article aims to describe the normal imaging anatomy and biomechanics of the elbow, the most commonly used MRI protocols and techniques, and common MRI findings related to tendinopathy, ligamentous and osteochondral injuries, and instability of the elbow.

A Comprehensive Review of Radiohumeral Synovial Plicae for a Correct Clinical Interpretation in Intractable Lateral Epicondylitis

PURPOSE OF REVIEW

Radiohumeral synovial plicae (RHSP) have been studied by different authors in different ways; in spite of this, the evidence is poor and the results are controversial and inconclusive even when it comes to referring to this elbow structure. The aim of this article is to review the embryologic development, anatomy and histology, pathophysiologic features, clinical manifestations, physical examination, imaging findings, and treatment of radiohumeral synovial plicae, for their correct clinical interpretation in patients with intractable lateral epicondylitis.

RECENT FINDINGS

Radiohumeral synovial plicae syndrome (RHSPS) can cause intractable lateral epicondylitis and can be easily confused with other clinical conditions affecting the elbow. Many clinicians are not familiar with radiohumeral synovial plica syndrome since there are not many studies about it and previous reports do not seem to reach a consensus. Although its role in elbow injuries and epicondylitis is accepted and its surgical treatment is effective, there is no clear consensus about clinically relevant aspects. RHSP are remnants of normal embryo development of the articular synovial membrane with different anatomical locations, size and shape. Traumatism or overuse can turn RHSP into symptomatic structures at any age and can be compressed between the radial and humeral heads during movement. This compression can cause pain and other symptoms such as snapping, catching, mobility restriction, pitching, clicking, locking, blockage, popping and swelling. Radiohumeral synovial plica syndrome (RHSPS) may be an isolated condition or it can be associated with other elbow abnormalities. The findings on physical examination and imaging diagnosis are multiple and variable. Nowadays, RHSPS are quite unknown and previous reports do not seem to agree, leading to misdiagnoses as epicondylitis and making this structure the main cause of some cases of "intractable lateral epicondylitis". The outcomes of surgical treatments are quite promising although more, higher quality research is needed. Taking this into account, this review is meant to be a starting point for new anatomical and clinical studies.

Positioning Techniques to Improve the Ultrasound Evaluation of the Elbow

We introduce an ergonomic positioning for sonographic scanning of elbow joint where the patient is lying semisupine on the examination bed. This is in contrast with the conventional positioning where the patient is sitting on the edge of the bed or across the table on a chair. Our proposed positioning is more comfortable for both the patient and ultrasound practitioner. It also allows immediate ultrasound-guided injections with lesser risk regarding a vasovagal syncope of the patient.

Magnetic resonance imaging of elbow injuries in children

Evaluating elbow injuries is challenging because of the complex anatomy of the joint. In children, injury patterns depend on the sports-specific mechanism as well as the stage of skeletal maturity. This article reviews the anatomy of the elbow and common injury patterns seen in children, with an emphasis on MRI and the throwing athlete. Imaging pitfalls specific to children are described.

Clinical and diagnostic outcomes in arthroscopic treatment for posterolateral plicae impingement within the radiocapitellar joint

Synovial plica is rarely diagnosed as cause of elbow pain. Impingemnt of posterolateral plicae in the radiocapitellar joint tends to be usually overlooked. The purpose of this study was to present outcomes of arthroscopic treatment in relatively large number of cases and propose reliable diagnostic test for posterolateral plicae of the radiocapitellar joint.From January 2000 to December 2010, 24 cases diagnosed with pathologic posterolateral radiocapitellar plica on arthroscopic finding were retrospectively reviewed. Magnetic resonance imaging (MRI) evaluation and preoperative physical examination were performed. The posterolateral radiocapitellar plica test newly proposed by the present study was also conducted. To measure postoperative clinical outcomes, the disabilities of the arm, shoulder, and hand (DASH) score and Mayo elbow performance score (MEPS) were employed. Minimum duration of follow up was 24 months.According to the preoperative MRI, pathologic radiocapitellar plica was identified in 17 cases (70.8%). Preoperatively, maximal tender point was present on the radiocapitellar joint line in 20 cases (83.3%) and mechanical symptoms were observed in 9 cases (37.5%). 6 cases (25%) demonstrated pain at terminal extension and limitation of extension. 20 (83.3%) cases tested positive for posterolateral radiocapitellar plica test. The sensitivity and specificity of the posterolateral radiocapitellar plica test were 83.3% and 87.5%, respectively. The accuracy value was 86.3%. Arthroscopic debridement of pathologic plica in the radiocapitellar joint demonstrated clinical improvements: DASH score was from 36.6 to 8.9 and MEPS was from 56.9 to 95.6 at the latest follow-up.Symptomatic impingement by the pathologic posterolateral plica of the radiocapitellar joint should be considered when posterolateral elbow pain which is refractory to conservative treatment, and other prevalent diseases are excluded. The posterolateral radiocapitellar plica test and radiocapitellar joint line tenderness could be recommended as reliable examination maneuvers to obtain accurate diagnosis. Arthroscopic debridement was an effective method for treating symptomatic plicae.

Unusual cause of elbow pain in a baseball pitcher

An adolescent, right hand-dominant, baseball pitcher presented to sports medicine clinic with posterolateral right elbow pain over 4 months. He rated his pain as 8/10 with pitching, especially at the late cocking phase of throwing. Prior to consult, he had rested 3 months from pitching, progressing to strengthening exercises, with no pain relief. On physical examination, he had 120° of active external rotation, 80° of active internal rotation, mild tenderness to palpation over the capitellum and normal elbow radiography. Magnetic resonance arthrogram of the right elbow revealed subtle, posterolateral joint capsular tear and adjacent synovial hypertrophy. The patient was diagnosed with elbow synovial fold syndrome that was causing impingement at the radiocapitellar joint and was referred to an orthopaedic surgeon. Arthroscopy revealed redundant tissue; scar formation at the radiocapitellar joint was debrided. The patient participated in physical therapy for 2 months and was able to start throwing 3 months later.

It's time to change perspective! New diagnostic tools for lateral elbow pain

PURPOSE

The presence of intra-articular findings that may complement the extra-articular pathology in lateral epicondilytis has been suggested, and a role for minor instability of the elbow as part of the causative process of this disease has been postulated. This study was designed to describe two new clinical tests, aimed at detecting intra-articular pathology in patients affected by recalcitrant lateral epicondylitis and investigate their diagnostic performance.

METHODS

Ten patients suffering of atraumatic lateral elbow pain unresponsive to conservative treatment were considered in this study. Two clinical tests were developed and administrated prior to arthroscopy: Supination and Antero-Lateral pain Test (SALT); Posterior Elbow Pain by Palpation-Extension of the Radiocapitellar joint (PEPPER). Sensitivity, specificity, predictive values and accuracy of SALT and PEPPER as diagnostic tests for seven intra-articular findings were calculated.

RESULTS

In 90% of the patients, at least one test was positive. All patients with signs of lateral ligamentous patholaxity or intra-articular abnormal findings had a positive response to at least one of the two tests. SALT proved to have a high sensitivity but a low specificity and is accurate in detecting the presence of intra-articular abnormal findings, especially synovitis. PEPPER test was sensible, specific and accurate in the detection of radial head chondropathy.

CONCLUSIONS

Two new diagnostic tests (SALT and PEPPER) were specifically designed to evoke pain from intra-articular structures. These tests could be a valid support in the diagnostic algorithm of recalcitrant lateral elbow pain. Positive findings may be indicative of a minor instability of the lateral elbow condition.

LEVEL OF EVIDENCE

Diagnostic study, development of diagnostic criteria on basis of consecutive patients, level II.

Intra-articular findings in symptomatic minor instability of the lateral elbow (SMILE)

PURPOSE

Lateral epicondylitis is generally considered an extra-articular condition. The role of minor instability in the aetiology of lateral elbow pain has rarely been considered. The aim of this study was to evaluate the correlation of lateral ligamentous laxity with aspects of intra-articular lateral elbow pathology and investigate the role of minor instability in lateral elbow pain.

METHODS

Thirty-five consecutive patients aged between 20 and 60 years with recalcitrant lateral epicondylitis who had failed conservative therapy and had no previous trauma or overt instability, were included. The presence of three signs of lateral ligamentous patholaxity and five intra-articular findings were documented during arthroscopy. The relative incidence of each of these was calculated, and the correlation between patholaxity and intra-articular pathology was evaluated.

RESULTS

At least one sign of lateral ligamentous laxity was observed in 48.6% of the studied cohort, and 85.7% demonstrated at least one intra-articular abnormal finding. Radial head ballottement was the most common sign of patholaxity (42.9%). Synovitis was the most common intra-articular aspect of pathology (77.1%), followed by lateral capitellar chondropathy (40.0%). A significant correlation was found between the presence of lateral ligamentous patholaxity signs and capitellar chondropathy (p = 0.0409), as well as anteromedial synovitis (p = 0.0408).

CONCLUSIONS

Almost one half of patients suffering from recalcitrant lateral epicondylitis display signs of lateral ligamentous patholaxity, and over 85% demonstrate at least one intra-articular abnormality. The most frequent intra-articular findings are synovitis and lateral capitellar chondropathy, which correlate significantly with the presence of lateral ligamentous patholaxity. The fact that several patients demonstrated multiple intra-articular findings in relation to laxity provides support to a sequence of pathologic changes that may result from a symptomatic minor instability of the lateral elbow (SMILE) condition.

LEVEL OF EVIDENCE

III.

Short-term results after arthroscopic resection of synovial plicae in the radiohumeral joint: a case series of 64 procedures

Introduction: Painful Synovial Plicae (SP) in the posterolateral corner of the radiohumeral joint may be confused with lateral epicondylitis. The SP may impinge between the radial head and the humeral capitellum causing pain and snapping. The aim of this study was to evaluate the short-term results after arthroscopic plica resection of the elbow.

Methods: In this case series, we included a consecutive series of 64 arthroscopies (60 patients) with arthroscopic plica resection of the elbow. Inclusion criteria were six months of lateral elbow pain and unsuccessful conservative treatment. Patients had either ultrasonography verified plicae or pain on palpation of the plica. Patients were evaluated with an Oxford Elbow Score (OES) preoperatively, after three months and after mean 22 months (range: 12–31) of follow-up. Furthermore, baseline characteristics were recorded including, gender, age, body mass index (BMI), occupation, smoking and cartilage damage.

Results: The mean age was 44 years (range: 18–66). In 13 elbows, International Cartilage Repair Society (ICRS) grade 1 lesions were present in association with the plica. Preoperatively the mean OES was 19 (95% CI: 17–20). At three and 22 month follow-up the OES increased to 33 (95% CI: 30–36) and 35 (95% CI: 32–38), respectively (p < 0.001). Cartilage injury and gender did not affect the outcome. We reported no complications.

Discussion: Arthroscopic plica resection of the elbow indicates an improved OES after three and 22 months. A randomized prospective trial is needed to validate the effect of arthroscopic treatment of synovial elbow plicae.

Long-term results after a free vascularized adipofascial graft for congenital proximal radioulnar synostosis with an average follow-up of 10 years: a series of four cases

BACKGROUND

The aim of this study was to observe the long-term and chronologic changes in clinical and radiologic findings after a free vascularized adipofascial graft interposition with radial osteotomy for congenital proximal radioulnar synostosis (PRUS).

METHODS

Six forearms in 4 patients with congenital PRUS who underwent a free vascularized adipofascial graft interposition combined with radial osteotomy were followed up for an average of 10 years (8-12 years) postoperatively. Extension and flexion angles of the elbow and pronation and supination angles of the forearm as well as radiographs were evaluated preoperatively and throughout the postoperative follow-up period.

RESULTS

The average extension/flexion angles of the elbow and the average pronation/supination angles of the forearm were 3°/130° and 14°/- before surgery, -4°/135° and 39°/23° at 1 year after surgery, 6°/138° and 44°/30° at 3 years after surgery, and -2°/139° and 35°/7° at the time of the final follow-up, respectively. Final radiographs showed hypertrophy of the radial head in 4 patients, dislocation of the radial head in 2 patients, and deformity of the radial head in 1 patient.

CONCLUSIONS

Extension and flexion angles of the elbow in patients with congenital PRUS were constant and the average range of pronation was relatively well maintained throughout the postoperative period, but the average range of supination decreased by 16° from 1 year postoperatively to the time of the final follow-up.

Anatomic relations between the lateral collateral ligament and the radial head: implications for arthroscopic resection of the synovial fold of the elbow

PURPOSE

The purpose of this study was to determine the anatomic relationship between the radial head and the lateral collateral ligament (LCL) and when the LCL would be at risk of iatrogenic injury during arthroscopic resection of the synovial fold.

METHODS

Thirty-four formalin-fixed upper extremities were dissected. A projection of the LCL onto the radial head was marked with a needle. The percentage of the posterior border of the radial head overlaid by the LCL was digitally measured. A portion of the projection of the LCL was statistically correlated with the overall diameter of the radial head.

RESULTS

The overall diameter of the radial head was 21.2 mm ± 2.3. The proportionate projection of the medial border of the LCL onto the radial head was 5.3 ± 1.6 mm on average. The lateral 25 % of the radial head was overlaid by the LCL with a maximum value of 40 % on average. The inter- and intraobserver reliability showed very good accordance with the digital measurements (r > 0.8).

CONCLUSION

Care must be taken when performing a resection in the lateral 40 % of the radial head, whereas resection in the medial 60 % of the radial head appears to be safe. The LCL is an important stabiliser of the elbow joint, a lesion of which by undeliberate arthroscopic dissection may lead to joint instability. Iatrogenic injury to the LCL presumably can be prevented when respecting the given data.

LEVEL OF EVIDENCE

Experimental study.