Tendon Ruptures After Distal Radius Fracture

Key Points

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The incidence of tendon ruptures after distal radius fracture is rare, currently 1%–3%, and generally occur within the first year after surgery. The extensor pollicis longus (EPL) or flexor pollicis longus (FPL) are most often involved tendons, and rupture of flexor or extensor tendons to the fingers were also reported.
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The key to prevent flexor tendon rupture is to properly position the plate, and Soong classification offers practical guide to ideal plate position.
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The key to prevent extensor tendon rupture is to avoid too long screws that dorsally protrude. The dorsal tangential/horizon/skyline or carpal shoot-through view offers a reliable verification intraoperatively, and/or a CT scan, postoperatively.
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Once clinical diagnosis is established, surgical exploration should proceed and hardware should be removed before proceeding to tendon reconstruction.
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Tendon transfer or grafting are two common option of surgical treatment and prognosis of these surgeries are believed to be reliable in achieving a satisfactory result.

Panel 1: Case Scenario

A 63 year-old, right hand dominant male presents with a spontaneous inability to flex his thumb after several months of pain along the course of the FPL. His medical history include a volar plate osteosynthesis of a distal radius fracture 2 years earlier after a skiing trauma ( Fig. 1 ). Clinical examination confirms an FPL tendon rupture and ultrasound identifies a rupture at the CMC-1 joint with a retracted proximal tendon stump that cannot be localized. What is the most effective approach for management of his rupture and how could it have been prevented?

Importance of the Problem

Tendon rupture after distal radius fractures were found with or without surgical treatment. The timing of the tendon rupture varies from days or months after fracture or many years after surgical treatment. The most common incidence is associated with open reduction and internal fixation when the plate is not placed in a correct position and most commonly involved tendons are extensor tendons. DeGeorge et al. reported among 647 cases of distal radius fractures (636 patients) with open treatment of extra-articular and intraarticular distal radius fractures with internal fixation between May 2000 and May 2015, there is 2 extensor pollicis longus (EPL) ruptures and 1 flexor pollicis longus (FPL) tendon rupture. The mean time to tendon rupture was 481 days with a range from 21 to 1599 days. This is a rather uncommon complications compared with other complications such as loose or painful hardware (48 cases) and tendinopathy (flexor tendon irritation in 16 cases, extensor tendon irritation in 11 cases). In a survey of distal radius fractures treated with volar plating in a prefecture in Japan, Naito et al. reported 10 FPL ruptures (0.35%), 8 EPL ruptures (0.29%), 1 rupture of the flexor digitorum profundus (FDP) tendon to index finger (0.04%) and 1 rupture of the extensor digitorum communis (EDC) (0.04%) out of a total of 2787 cases. Thorninger et al. followed 576 patients with distal radius fractures treated with volar plating and found 5 flexor tendon ruptures and 12 extensor tendon ruptures. The incidence of tendon rupture was 2.9%.

In a systematic review of the 56 studies (6278 patients) before 2017, Azzi et al. reported overall tendon-related adverse events were recorded in 420 patients (6.8%). The incidence of tendon ruptures (EPL, FPL, FDP plus flexor digitorum superficialis, or EDC) was 1.5% with volar plates and 1.7% with dorsal plates. The incidence of tenosynovitis was 4.5% with volar plates and 7.5% with dorsal plates. Other reported detailed the ruptures of the flexor carpi radialis tendon or all finger flexors, or patients with late ruptures or the ruptures in nonoperative patients.

The incidence of tendon rupture was reported in 1%–3% of the cases with volar or dorsal plating according to the recent large patient cohorts, which appears not differ from the data in earlier publications (1%–2%). Though tendon rupture was seen in distal radius fracture without open reduction and surgical plating, our chapter will focus on questions and evidence of tendon rupture relating to surgical treatment.

Main Question

How are tendon ruptures after distal radius fracture most effectively prevented, diagnosed, and treated?

Current Opinion

Tendon rupture secondary to conservatively treated distal radius fractures are excessively rare and may go unnoticed if a high index of suspicion is not maintained. The vast majority of tendon ruptures following distal radius fractures are related to hardware malposition, have an insidious onset postoperatively after surgery and are preventable.

Finding the Evidence

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Cochrane search: Distal Radius Fracture
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Pubmed (Medline): (“Radius Fractures” [Mesh] OR distal radius fracture*[tiab]) AND (tendon rupture*)
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Bibliography of eligible articles that were not in the English language were excluded.

Quality of the Evidence

Level II:

Prospective study: 1

Level III:

Systematic review and metaanalysis: 1
Retrospective comparative studies: 3

Level IV:

Case series: 13

Findings

Prevention

The EPL tendon is at risk for spontaneous rupture even in the absence of identifiable predisposing risk factor. It has been suggested that rather than pure mechanical irritation, vascular, and metabolic factors may also play a substantial role in the etiology of this exceedingly rare diagnosis. Spontaneous EPL rupture with conservative treatment of a usually nondisplaced fracture as a result of retinaculum remaining intact—with increased pressure in EPL compartment leading to ischemia—often will occur within 4–8 weeks post injury. Signs and symptoms include initial discomfort with thumb use and soon tenderness over EPL compartment. The patient is best informed from outset that there is low risk but if discomfort persists to return as may need to have compartment opened.

With regard to (post-)operative prevention, Soong et al. proposed a grading system to classify the palmar prominence of the plate relative to the watershed line. Soong classification is based on standard lateral plain radiographs: (a) Grade 0: The plate is dorsal to the volar critical line and proximal to the volar rim. (b) Grade 1: The plate is palmar to the volar critical line, but proximal to the volar rim. (c) Grade 2: The plate extends beyond the level of the volar rim.

Recent reports of the Soong classification with incidence of plate removal and tendon ruptures were summarized in Table 1 . The cohort with the largest number of patients (113 patients) showed a statistically significant correlation between FPL rupture as well as flexor tenosynovitis and the plate position according to the Soong classification. Soong grading is a valuable tool to classify the position of palmar plates relative to the watershed line and to detect patients at risk of tendon injuries ( Figs. 1 and 2 ). Elective removal of implants after union should be considered in patients with a higher Soong grade (1 and 2) ( Box 1 ).

Table 1

Soong Grades of Palmar Plates Removed After Distal Radial Fracture.

Authors	years	Patients With Implant Removal	Grade 0	Grade 1	Grade 2	Tendon Ruptured
Snoddy et al.	2015	33	14 (42%)	10 (30%)	9 (27%)	1
Lutsky et al.	2015	37	4 (11%)	28 (76%)	2 (5%)	0
Selles et al.	2018	54	10 (19%)	20 (37%)	24 (44%)	0
Goren et al.	2020	113	28 (25%)	48 (42%)	37 (33%)	16

Box 1

Prevention and Clinical Diagnosis of Tendon Rupture.

1.

Proper position of a plate is a measure to decrease the risk of tendon rupture. Avoid placing the distal rim of a standard volar plate palmar and distal to the watershed line. ( Figs. 3 and 4 ).
2.

Do not project the screws over the dorsal cortical surface of the distal radius in the standard lateral view. An additional dorsal tangential/horizon/skyline or carpal shoot-through is more accurate and reliable to identify protruding screws ( Fig. 5 ).
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Soft tissue coverage over the plate is recommended.
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If intraoperative reduction of the fracture requires the plate to locate in a position of Soong grade 2 or 3, early removal of the plate after fracture healing should be considered. If tendon irritation presents, removal is highly suggested.
5.

Loss of active thumb interphalangeal flexion (or extension) indicates rupture of the FPL (or EPL) tendon, and loss of finger flexion at the distal interphalangeal joint indicates injuries to the finger flexor tendons. Weakness in finger extension suggest the possible rupture of finger extensor tendons.
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The median reported interval to rupture after surgery is 9 months with exceptional cases being reported up to 10 years. Most patients have prodromal symptoms of crepitus, pain with finger motion, clicking or a rubbing sensation prior to rupture.