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Three Part Question

In [adult patients with a suspected distal bicep rupture] is the [hook test a reliable and accurate] physical test at [confirming diagnosis].

Clinical Scenario

A 48 year old male presents to the emergency department following a fall at work. He recalls grabbing a pole as he tried to slow his fall. He complains of right shoulder and elbow pain. Active elbow flexion and supination is painful and weak. Radiographs exclude fracture and/or dislocation at the shoulder and elbow. You suspect a distal bicep injury and recall there is a time urgency to manage such injuries. You perform the 'hook test' but are unsure of its reliability and accuracy in detecting Distal Biceps Tendon Rupture (DBTR). You consult the literature to support your discussion to expedite this case to the upper limb orthopaedic team.

Search Strategy

Search Strategy
Medline 1946 to present
EMBASE 1974 to present
CINAHL 1981 to present
BNI 1922 to present
{Distal Bicep Rupture} AND {Hook test} AND {assessment OR diagnosis}
LIMIT to Adults

Search Outcome

17 papers were retrieved of which 8 were duplicates. Other papers excluded were case reports and reviews. Therefore 4 papers were identified as pertaining to the clinical question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
O'Driscoll, S. W., et al. 2007 US	45 patients were assessed using the 'hook test' prior to surgical exploration and repair of the distal biceps.	Retrospective Cohort Study (diagnosis)(L2)	Sensitivity and specificity of 'Hook test' and MRI in detecting DBTR	Hook test: Sensitivity and specificty 100%, MRI 85% sensitivity, 92% specific	No individual case data on time from injury to clinic assessment. Chronic recorded as >21 days after injury but no range recorded Single assessor reduces generalisability
Devereaux, MW, ElMaraghy, AW 2013 Canada	48 patients were assessed using three special tests, the 'Hook test', Passive Forearm Pronation (PFP) , and the Biceps Crease Interval (BCI) to determine distal biceps tendon injury. Comparisons made with intra operative findings and/ or MRI or US	Prospective Cohort Study (Diagnosis) (L2)	Sensitivity and specificity for each individual special test and when combined	Hook - sensitivity- 81% (8 false negatives) specificity - 100% PFP - sensitivity - 95% (2 false negatives), 100% specificty BCI - 88% (5 false negatives), 50% specificty Combined in unequivical (n=35) 100% sensitivity, 100% specificity	Failed to include inter-rater reliability of each special test No sample size estimates Fails to identify if MRI or US is used for equivocal findings No discussion of Ultrasound specificity/ sensitivity in detection of DBTR despite its use No individual case data on time from injury to clinic assessment although range is included
ElMaraghy, A, Devereaux, M 2013 Canada	17 patients with suspected DBTR were assessed using the Hook test, PFP, BCI, and Bicipital aponeurosis flex test (BAFT) and compared with intraoperative findings.	Retrospective Cohort Study (Diagnosis)(L2)	Sensitivity, Specificity and diagnostic accuracy of the BAFT in detecting bicipital aponeurosis rupture. Findings reviewed in relation to Hook test findings.	Sensitivty - 100%, 90% specificity, overall diagnostic accuracy - 94% Hook test - 3 of 8 patients displayed false negative	No data on intra and inter tester reliability. Partial data collection is not included Fails to acknowledge complexity of clinical manoeuvre Small sample Bold narrative on surgical repair technique documented but unrelated to study aim/ findings
Pallante, GD, O'Driscoll, SW 2019 US	57 repairs (56 patients) who had undergone surgical DBT repair for partial tear, complete rupture, and revision repair were routinely assessed using the Hook test to determine DB integrity at 6 weeks, 3-4 month and one year post procedure	Retrospective Cohort Study (Diagnosis) (L3)	Time to return an intact Hook Test post DBTR repair	51/57 repairs returned an 'intact' hook test by a mean of 10 weeks post surgery	Specificity and sensitivity of modified Hook test not documented No confirmatory MRI of which to compare 'intact' Hook test findings. Resisted testing is suggested to indicate partial tear or tendinosis but this is not confirmed with evidence Single assessor reduces generalisability

Comment(s)

Almost exclusively occurring in middle aged males; distal biceps tendon rupture (DBTR) is a relatively rare injury. Accounting for only 3% of all tendon injuries; it is often a result of a sudden eccentric load to the bicep causing complete or partial rupture1. Active individuals with an acute complete DBTR require timely surgical repair. Delays to intervention (>6/52) is associated with greater surgical difficulty and post operative complications2. All four papers reviewed in this article highlight that delayed and missed diagnosis is common. Variation in 'textbook' signs and symptoms and/ or clinical examination difficulty is often cited. It should be noted that the referenced papers within these publications are dated. Equivocal objective findings and uncertainty can prompt unnecessary imaging requests. Despite all four papers reporting some use of soft tissue imaging; these were often by a private provider, post specialist review, or as part of the study. Proposed by O'Driscoll and colleagues, The Hook Test was reported by the authors to be both 100% specific and 100% sensitive in detecting complete DBTR in 33 patients3. Devereaux and colleagues however reported that the hook test resulted in a sensitivity of 81% with eight false negatives recorded in their 48 patient cohort4. Interestingly; all eight were chronic cases. Over 50% of the cohort in the O'Driscoll paper were also recorded as chronic (>21 days after injury) but no further data is available. The average time between injury and presentation to specialist clinic in the Devereaux paper was 76 +/- 158.8 days with a broad range of 1-913. Devereaux and colleagues suggest the lower sensitivity may be due, in part, to inadvertently hooking the Bicipital Aponeurosis (BA) or scarred tissue in more chronic cases. The authors propose a combination of three clinical tests and report 100% sensitivity and specificity in detecting DBTR when all three outcomes are in agreement. ElMaraghy and Devereaux further explored the hypothesis of the BA impacting accurate detection of DBTR5. An intact BA was found intra-operatively in half of the 16 patient cohort with complete DBTR. The authors highlighted that an intact BA can mislead clinicians as it may reduce biceps tendon retraction often seen in complete DBTR. They hypothesised that their proposed BA Flex Test, which resulted in 100% sensitivity and 90% specificity in detecting BA rupture, may aid decision making around urgency of DBTR surgical repair. A recent paper in 2019 utilised an updated version of the Hook Test to determine biceps tendon integrity following surgical repair6. Over 60%, and 88% of the 57 repairs returned an intact finding at two and four months respectively. Caution however should be applied to their findings as no confirmatory MRI was included within this study. Instead the authors reference sensitivity and specificity data from their previous 2007 Hook test study but fail to acknowledge that data was obtained with the previously unmodified Hook test. Of the four studies within this report; clinical assessments are completed by experienced specialist clinicians within dedicated clinics, in two specialist upper limb centres. Small study numbers with a propensity for chronic presentation also limits how transferable the results are to non specialists working in an acute front line trauma setting.

Clinical Bottom Line

The Hook Test is a simple objective clinical test which is accurate and reliable in detecting DBTR when carried out by skilled clinicians in specialist upper limb clinics. Further studies are, however, needed to explore its accuracy and reliability when used by non specialist clinicians in acute front line settings.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. O'Driscoll, SW The Hook Test for Distal Biceps Tendon Avulsion Am J Sports Med 2007; 1865-1869
2. Devereaux, MW Improving the Rapid and Reliable Diagnosis of Complete Distal Biceps Tendon Rupture: A Nuanced Approach to the Clinical Examination Am J Sports Med 2013;41:1998-2004
3. ElMaraghy, A The “bicipital aponeurosis flex test”: evaluating the integrity of the bicipital aponeurosis and its implications for treatment of distal biceps tendon ruptures. J Shoulder and Elbow Surgery 2013; 22:908-914
4. Pallante, GD Return of an Intact Hook Test Result: Clinical Assessment of Biceps Tendon Integrity After Surgical Repair Ortho J Sports Medicine 2019;7:1-6