Distal biceps tendon ruptures – the relation of radiological retraction and chronicity to the ability of tendon reattachment and long-term functional outcomes

Abstract

Aims

To assess whether the degree of radiological retraction and chronicity of distal biceps tendon ruptures are related to the ability to reattach the tendon and long-term functional outcomes.

Methods

Analysis of consecutive patients undergoing surgery for distal biceps tendon ruptures by a single surgeon. Measurements regarding the site and degree of tendon retraction in relation to anatomical landmarks following rupture were correlated with intraoperative findings. Postoperative functional outcomes were assessed in cases with >12 months follow-up.

Results

24 cases of distal biceps tendon ruptures treated surgically were identified. Mean tendon retraction was 6.0 cm (range 1.2–9.5) from the radial tuberosity. 22 cases were reattached successfully. 2 required ligament augmentation/bridging using a synthetic ligament. In 2 cases the tendon could not be reattached due to poor quality of the tendon stump. Ability to reattach the tendon was unrelated to degree of radiological retraction or chronicity of rupture. Degree of retraction was not related to rupture chronicity. All reattachments healed with no re-rupture at follow-up with no substantial motion loss. In 17 cases >12months follow-up the DASH and OES were not related to retraction or chronicity of rupture.

Conclusions

Radiological retraction and chronicity are not related to the ability to reattach distal biceps tendon ruptures or their clinical outcomes, hence should not discourage surgical exploration and attempted reattachment. Substantial tendon retractions can occur acutely and reattachment in considerable flexion did not produce any significant motion loss. Some cases will need augmentation or gap bridging and augmentation devices need to be available at surgery.

Level of evidence

Level IV Retrospective Study Defined.

1. Introduction

Distal bicep tendon ruptures typically occur in men between the ages of 40–60 after an eccentric extension load is applied to the elbow in flexion and are being reported with increasing frequency.^1,2 Patients often describe a painful tearing sensation and present with ecchymosis and swelling around the antecubital fossa.

Loss of integrity of the distal biceps tendon may result in substantial weakness, mainly in supination of the flexed elbow with increased fatiguability reported.³ The weakness in elbow supination and elbow flexion has been reported as high as 50% and 30% respectively.^4,5 Hence, early surgical reattachment has been advocated in all but low demand patients in order to restore strength and function.^6,7

Whilst diagnosis is predominantly clinical, radiological imaging (Ultrasound(US)/Magnetic Resonance Imaging(MRI)) is often arranged prior to surgery to confirm the diagnosis and may influence decision making. Diagnosis of complete distal biceps tendon ruptures may be delayed due to misdiagnosis or late presentation. This may, in principle, result in scarring and proximal retraction of the muscle belly, or loss of tendon substance which can make subsequent mobilisation of the tendon and reattachment difficult or not possible.² Hence, there may be a tendency for radiological tendon retraction and rupture chronicity to guide as to whether to attempt surgical reattachment, with cases exhibiting substantial retraction or presenting late, being denied surgery unnecessarily.

Our aims were to determine whether the degree of distal biceps tendon retraction as found on preoperative imaging and rupture chronicity are related to the ability to achieve primary surgical reattachment with or without augmentation of the distal biceps tendon, and whether they are related to post-operative clinical outcomes.

2. Materials & methods

2.1. Patients

We set out to perform an analysis of patients undergoing surgical repair for distal biceps tendon ruptures at our institution. Local ethical approval was obtained from the Research and Development department at our institution for the purposes of undertaking the study. We performed a retrospective search using operative records and theatre databases to identify all patients who had undergone consecutive surgical repair for distal biceps tendon ruptures by the senior author. Acute ruptures were defined as those having been repaired within 4 weeks of injury and with those occurring after 4 weeks defined as chronic as previously described.^2,8

All patients undergoing surgical reattachment were included in our analysis to assess repairability of the tendon. Presentation details and timings of injuries were recorded. Where dates of injuries were unclear, the date of Emergency Department attendance was used as the date of injury. Operative details were reviewed noting use of any augmentation using a synthetic ligament (Ligament Augmentation & Reconstruction System, LARS™, Corin Group, Cirencester, UK) available at our institution.

All patients identified had preoperative imaging either with US or MRI. MRI sequences were reviewed independently by an experienced musculoskeletal radiologist at our institution. The degree of tendon retraction was described as the distance measured on sagittal MRI sequences between the anatomical insertion point on the radial tuberosity to the most distal point of the ruptured tendon. The position of the end of the ruptured tendon in relation to the elbow joint (distal or proximal) was also noted. We sought to standardise retraction measurements to account for the degree of retraction of the biceps tendon relative to the length of the humerus (in patients with preoperative MRI scans), to give a more clinically useful measurement since the significance of tendon retraction in terms of distance may be variable relative to the overall size and stature of the patient. Previous anthropometric studies have suggested that distal segments of the humerus may correlate with total humeral length.9, 10, 11 Bicondylar width between the medial and lateral epicondyle is one such measurement which has been shown to be related to total humeral length^10,11 and measurement is reproducible using coronal MRI sequences of the elbow. Starting from distally and progressing proximally we identified the first section on the coronal MRI images on which both the medial and lateral epicondyles were visible. We measured the inter-epicondylar distance (tip of medial epicondyle to tip of lateral epicondyle) perpendicular to the humeral shaft (distance x). We then identified on sagittal images the section with the most distant visible tendon and measured the distance between the most distal part of that tendon to a point perpendicular to the level of the articular surface of the elbow (distance y)(Fig. 1). y/x gave a standardised measure of tendon retraction which was also used to describe tendon retraction. A negative value of y/x indicates retraction distal to below the elbow joint and a positive value indicates retraction above the elbow.

$$y/x=\frac{Tendonretractionfromelbowjo\mathrm{int}lineonsagittalimage,y}{Interpicondylardistanceoncoronalimage,x}$$

Fig. 1.

Example y/x measurements of tendon retraction on MR Images: left image-coronal x, right image-sagittal Y.

2.2. Interepicondylar distance on coronal image, x

Patients were assessed in person for the purposes of this study. Those that could not attend were assessed by utilising their medical records and via a phone consultation where possible. Range of motion was measured using a goniometer and compared to the contralateral limb. Strength was measured using the Oxford Scale and a neurovascular assessment was performed with particular evaluation of the Lateral Antebrachial Cutaneous nerve (LABCN). Patient reported outcome measures were obtained using the Oxford Elbow Score (OES) and Disability of the Arm, Shoulder and Hand (DASH) score.^12,13

2.3. Surgical technique

All patients were operated on by the senior author at a single institution over a 7-year period between 2011 and 2018 using a single incision technique.¹⁴ An “S” shaped incision is utilised centred over the antecubital fossa dissecting down to and exposing the biceps tendon insertion on the radial tuberosity. Proximally the ruptured tendon end is identified and mobilised. Two 3.5 mm suture anchors (Twinfix ULTRABRAID, Smith & Nephew, London, UK), each with two suture strands are inserted into the radial tuberosity with the aid of an image intensifier. These suture strands are passed through the tendon and tightened in a set sequence to produce an ‘L’ shaped reattachment.¹⁴ We accepted high flexion reattachments, with most cases performed in more than 90° flexion. In cases whereby the tendon is markedly tenuous or difficult to mobilise and attach to the tuberosity without excessive tension, the LARS™ Ligament Augmentation & Reconstruction System (Corin, Gloucestershire) is used as an augmentation/interposition graft.

Following surgical reattachment, patients are placed into plaster set at about 90-100⁰ flexion for 2–4 weeks and are subsequently immobilised in either plaster or a hinge elbow brace up to a total of 6–8 weeks post-operatively before beginning mobilisation with physio, avoiding heavy lifting activities for up to 12 weeks.

3. Statistical analysis

Results were collated and analysed using Microsoft excel and SPSS (version 20.0, IBM) software. Normality tests for data distribution were tested using statistical software. Simple descriptive statistics were included. Non-Parametric testing was carried out using the Mann-Whitney U test and for parametric data an Independent Sample T-Test was used for assessing differences in outcomes between subgroups. Fisher's exact test was used to ascertain differences between nominal variable groups in subgroup analysis. A two-tailed 5% significance level was used to assess the outcome measures for statistical significance.

4. Results

A total of 24 cases were included for primary analysis. All cases were male with a mean age of 45.2 years (±7.8). Mean time to surgery was 44.9 days (±64.4). 20/24 (83%) cases had surgery within 7 weeks. 14/24 (58%) cases were operated on within 4 weeks of injury and 7/24 (29%) between 4 and 7 weeks. 3 cases were operated on beyond 4 months due to delayed presentations and circumstances preventing expedited surgery. Case demographics are shown in Table 1.

Table 1.

Demographic data.

Variable	Mean (+/-S.D)	Range
Age (years)	45.2 (±7.8)	26–55
Time to surgery (days)	44.9 (±64.4)	4–284
Time to Imaging (days)	15.4 (±17.2)	1–80
Follow up (months)	47.6 (±24.9)	13–81

2 patients were unable to attend the hospital for clinical review, here an assessment was made during a phone consultation (OES and DASH questionnaire as well as a limited clinical review). 1 patient was lost to follow-up and information was gathered by review of clinical notes. 1 patient had an Ultrasound scan in which a retrospective meaningful assessment of tendon retraction could not be made.

22/24 (92%) had successful reattachment of the distal biceps tendon, whilst 2 had failed attempted reattachment. In both of these cases, the tendons were found to have marked degeneration intraoperatively with fraying and retraction. The tendon was noted intraoperatively to be unable to hold stitches therefore mobilisation and reattachment could not proceed in these cases. One of these cases had opted for brachialis tenodesis preoperatively in the event that primary reattachment could not occur and this was done intraoperatively. In the other case no reattachment or tenodesis took place. Both of these cases had tendon retraction above the level of the elbow joint with 8 cm and 7 cm retraction from the radial tuberosity. Their rupture chronicity was 139 days and 34 days.

Mean tendon retraction from anatomical insertion on the radial tuberosity to ruptured tendon end in our series was 6.0 cm (±2.4, range 1.2–9.5 cm). Mean y/x (distance of tendon retraction from elbow joint line,y/interepicondylar distance,x) was 0.36 (±0.50). 16/22 (73%) patients successfully reattached had above elbow joint tendon retraction. 2/22 (9%) successful reattachments required LARS ligament augmentation in order to supplement/bridge the repair intraoperatively, both of these cases had retraction above the elbow.

Time to surgery had no impact on ability to reattach the biceps tendon intraoperatively, (Mann-Whitney U test p-0.181). When comparing groups regarding chronicity of surgery (<4 weeks vs > 4 weeks) and degree of biceps tendon retraction in relation to the elbow joint, there was no association between these groups and the ability to successfully reattach the tendon (Fisher's Exact test p-0.999, p-0163). Similarly, when looking at absolute tendon retraction from anatomical insertion on the radial tuberosity and measurement y/x, there was no effect on ability to reattach the tendon (independent t-test p-0.379, p-0.221).

All cases that underwent surgical reattachment had clinically intact biceps tendons recorded at last follow-up with no identifiable re-ruptures.

4.1. Assessment of patients with >12 Months follow-up

Patients reviewed at more than 12 months had median DASH score of 2.5 (IQ range 0.0–14.2) and OES of 47.0 (range 40.0–48.0)(Table 2).

Table 2.

Distal Biceps Reattachment Results attending follow-up, >12months.

Case	Side	Image Modality	Time from Injury to Reconstruction (Days)	Age (y)	Reattached Successfully?	Tendon Retraction from Radial Tuberosity (cm)	Tendon in Relation to Elbow Joint	Trans-epicondylar Width (mm) X	Retraction from Elbow Joint (mm) Y	Measurement y/x	Follow-Up From Surgery (months)	Oxford Elbow Score	DASH	Return to Work	Strength Supination Oxford Elbow Scale	Strength Flexion Oxford Elbow Scale	LABCN Sensation	Additional Complications
1	Left	USS	14	51	Yes	4.0	Below	N/A	N/A	N/A	81	48	0	Yes	5	5	Normal	None
2	Right	MRI	4	38	Yes	7.0	Above	55.2	2.9	0.05	78	42	14.2	Yes	5	5	Normal	None
3 #	Right	MRI	13	55	Yes	7.0	Above	63.1	1	0.10	76	14	70	No	4	4	Altered	CRPS
4**	Left	MRI	25	48	Yes	8.5	Above	66.1	44.7	0.68	80	48	0	Yes	5	5	Normal	None
5	Left	USS	8	51	Yes	3.0	Below	N/A	N/A	N/A	66	48	0	Yes	5	5	Normal	None
6	Left	MRI	44	41	Yes	1.2	Below	65.1	−24.6	−0.38	65	48	0	Yes	5	5	Normal	None
7	Left	MRI	7	35	Yes	8.8	Above	60.4	37.7	0.62	51	46	5	Yes	4	5	Normal	None
8*	Left	USS	139	44	Fail Brachialis Tenodesis	8.0	Above	N/A	N/A	N/A	39	N/A	N/A	N/A	N/A	N/A	N/A	N/A
9	Right	MRI	13	42	Yes	4.3	Below	61.5	−35.7	−0.58	43	38	14.2	Yes	4	4	Altered	None
10	Right	MRI	23	49	Yes	7.7	Above	64.3	57.3	0.89	33	41	13.3	Yes	5	5	Altered	None
11	Left	MRI	169	51	Yes With LARS Augment	6.0	Above	42.6	38.3	0.90	75	48	0	Yes	5	5	Normal	None
12*	Right	MRI	30	52	Yes	6.0	Above	55.8	14.7	0.26	27	40	12.5	Not Available	Not Available	Not Available	Not Available	None
13	Right	MRI	25	43	Yes With LARS Augment	8.0	Above	60.4	45.3	0.75	31	31	17.5	Yes	5	5	Altered	None
14	Right	USS	35	32	Yes	3.0	Below	N/A	N/A	N/A	21	48	0	Yes	5	5	Normal	Superficial wound infection
15	Right	MRI	46	48	Yes	5.5	Above	56.4	16.9	0.30	23	47	2.5	Yes	5	5	Normal	None
16	Left	MRI	15	26	Yes	9.5	Above	66.9	53.8	0.80	19	45	0	Yes	5	5	Normal	PIN palsy resolved 6 months
17**	Right	MRI	15	49	Yes	7.5	Above	65.2	32.8	0.50	75	48	0	Yes	5	5	Altered	None
18	Right	USS	34	43	Fail No Reattachment	7.0	Above	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A
19	Right	MRI	31	54	Yes	1.2	Below	59.2	−28	−0.47	13	47	10	Yes	5	5	Altered	PIN palsy resolved 6 months
20	Right	USS	15	45	Yes	Not Available	Above	N/A	N/A	N/A	24	48	2.5	Yes	5	4	Normal	Nil
21*	Left	USS	284	54	Yes	Not Available	Not Available	N/A	N/A	N/A	27	40	15	Yes	Not Available	Not Available	Normal	Nil
22***	Left	USS	13	53	Yes	Not Available	Above	N/A	N/A	N/A	Not Available	Not Available	Not Available	Not Available	Not Available	Not Available	Not Available	Not Available

Further subgroup analysis on these patients with >12 months follow up was performed to assess effects on secondary outcomes. Cases with >7 weeks delay to surgery were excluded from this subgroup analysis.

There were no statistically significant differences found in our study on long term outcomes between subgroups based on retraction and chronicity. Retraction above and below the elbow did not effect patient recorded scores or functional outcome measures and patients satisfactorily regained movement and strength at follow-up with no difference between groups(Table 3). Taking into account the absolute degree of tendon retraction from the radial tuberosity there was no correlation with patient recorded outcome scores OES (r-0.279, p-0.296) and DASH (r 0.173 p-0.522). Amount of tendon retraction was not associated with LABCN altered sensation (p-0.846). When looking at the level of retraction in relation to measurement y/x, there was no statistically significant correlation between y/x and satisfaction scores OES (p-0.925) and DASH (p-0.634). Likewise, y/x was not associated to altered sensation in LABCN (p-0.478), loss of strength (p-0.330) and loss of extension (p-0.097).

Table 3.

Outcomes by Retraction Above vs. Below Elbow Tendon Repair (with >12 month follow-up and recorded outcome measures, up to 7 weeks).

	All Cases n = 17 Median (IQ Range)	Above Elbow n = 11 Median (IQ Range)	Below Elbow n = 6 Median (IQ Range)	P value
Oxford Elbow Score	42.8 (40.5–48.0)	40.9 (40.0–48.0)	46.2 (44.8–48)	0.131
DASH Score	9.5 (0.0–13.8)	12.5 (0.0–14.2)	4.0 (0.0–11.1)	0.192
Supination (0)	87 (85–90)	86 (80–90)	89 (89–90)	0.193
Flexion (0)	136 (131–140)	134 (130–140)	139 (134–144)	0.340
Extension Loss (0)	2 (0–3)	2 (0–6)	1 (0–1)	0.433
Supination strength	4.8 (5.0–5.0)	4.8 (4.8–5.0)	4.8 (4.8–5.0)	0.873
Flexion Strength	4.9 (5.0–5.0)	4.9 (5.0–5.0)	5.0 (5.0–5.0)	0.386

Long term functional outcome scores and range of motion were similar between acute and chronic re-attachment groups (Fig. 2. Table 4.) The LARS ligament augmentation was needed once in the acute group and once in the chronic group.

Fig. 2.

Median Outcome Scores by Chronicity (with >12 month follow-up and recorded outcome measures up to 7 weeks).

Table 4.

Chronicity on Outcome Measures (with >12 month follow-up and recorded outcome measures, up to 7 weeks).

	All Cases (within 7 weeks) n = 17 Median (IQ Range)	Acute ( < 4 weeks) n = 12 Median (IQ Range)	Chronic (4–7 weeks) n = 5 Median (IQ Range)	P value
Oxford Elbow Score	47.0 (40.5–48)	45.5 (38.8–48)	47.0 (43.5–48)	0.512
DASH Score	2.5 (0.0–13.8)	3.8 (0.0–14.2)	2.5 (0.0–11.3)	0.547
Supination (0)	90 (85–90)	90 (85–90)	90 (83–90)	0.804
Flexion (0)	140 (131–140)	138 (130–140)	140 (136–143)	0.380
Extension Loss (0)	0 (0–3)	0 (0–4)	0 (0–5)	0.999
Supination strength	5.0 (5.0–5.0)	5.0 (4.3–5.0)	5.0 (5.0–5.0)	0.283
Flexion Strength	5.0 (5.0–5.0)	5.0 (5.0–5.0)	5.0 (5.0–5.0)	0.527

Time from injury to radiological assessment was not related to degree of absolute tendon retraction (r-.105 p-0.649) or measurement y/x (r.233, p-0.352) (Fig. 3.).

Fig. 3.

a Degree of Tendon Retraction from Anatomical Insertion vs. Time from Injury to Imaging

b. Measurement y/x (tendon retraction from elbow joint on sagittal image –y, inter-epicondylar distance on coronal image-x) vs. Time from Injury to Imaging.

6/18 cases (33%) had altered Lateral Antebrachial Cutaneous Nerve (LABCN) sensation at follow up. Altered LABCN sensation was not associated with larger tendon retraction (p-0.846), or y/x ratio (p-0.478) or rupture chronicity (p-0.600). Altered LABCN sensation was related to higher DASH scores (p-0.019) and lower OES scores (p-0.031).

2 patients in our study suffered with a transient post-surgical Posterior Interosseous Nerve (PIN) palsy which fully recovered with no lasting motor deficits. All except 1 case returned to work. This patient was noted to have LABCN dysesthesia and was diagnosed as having developed Chronic Regional Pain Syndrome (CRPS) postoperatively along with substantial shoulder symptoms unrelated to his biceps tendon injury or surgery. 2 cases changed their job to involve less heavy manual work.

5. Discussion

Surgical reattachment of distal biceps tendon ruptures is often the preferred management option in order to prevent morbidity from loss in elbow supination and flexion^6,7 strength. However, the question as to whether the degree of tendon retraction and rupture chronicity are related to the ability to perform primary surgical reattachment and to clinical outcomes has not yet been adequately addressed. Hence, there may be a tendency for substantially retracted or chronic ruptures to be deemed irreparable or warrant reconstruction with autograft or allografts.

In our series, 92% of patients could be re-attached primarily with 9% requiring synthetic ligament augmentation. Degree of tendon retraction and chronicity had no significant bearing on ability to reattach the tendon or on functional outcome measures. Furthermore, immobilization of patients post-operatively in substantial flexion did not produce any cases of extension loss in our series. These findings reinforce those reported by Morrey et al.¹⁵ who demonstrated that even tight high flexion repairs can regain full extension over time. This study hypothesized the ability to regain motion was due to the ability of the biceps to stretch out over time. Muscle fibres have been show to adapt by a form of longitudinal growth by recruitment of additional sarcomeres in series to lengthen existing fibres without altering resting sarcomere length.¹⁶

There was no significant correlation between tendon retraction and rupture chronicity, with large retractions observed in cases investigated radiologically soon after injury. This suggests that tendon retraction in distal biceps tendon ruptures may be largely due to a springing action of the detached tendon acutely rather than due to loss of tendon substance or muscle contracture over time.

There is no current accepted consensus for timing of surgery for attempted distal biceps reattachment. Some surgeons may attempt reattachment only in early ruptures and may perform autograft or allograft reconstructions in more chronic cases. In our series, outcomes were similar in acute and chronic ruptures. Although most of our cases were operated within 7 weeks and hence any interpretations with regards to delay can only be extrapolated up to that delay, one of our cases was successfully primarily re-attached at 9 months post injury with good outcomes. Our findings are in accord with those of Anakwenze et al.⁸ which demonstrated similar outcomes with acute and chronic reattachments (defined as those occurring within 4 weeks and those after 4 weeks). There was found to be no difference in outcomes between the 12 acute repairs and 6 chronic repairs in that study. Furthermore Dillon et al. demonstrated similar long term outcomes in terms of function and strength between acute and chronic groups (again using less vs. more than 4 weeks) in a study of 27 patients undergoing single incision endobutton repair¹⁷ We feel that as long as the biceps tendon can be mobilised and re-attached to its anatomical footprint with or without synthetic ligament augmentation or bridging, satisfactory clinical outcomes can be achieved.

Our findings suggest that distal biceps tendon ruptures may be explored with attempted primary re-attachment (or with augmentation/bridging with synthetic ligament) up to about 7 weeks post injury despite the degree of tendon retraction. Our experience also suggests that on occasion irreparable tendons may be encountered due to loss of tendon substance or structural integrity and therefore patients should be informed of this possibility preoperatively. In such cases graft reconstruction might be considered at the same or later setting depending on graft availability and surgical expertise.

Complication rates in distal biceps tendon repairs have been estimated to be as high as 25–33%.^18,19 In our series, we noted a number of patients who developed lateral antebrachial nerve (LABCN) paraesthesia despite intra-operative identification and protection of the nerve. This is in line with previous reports of LABCN dysfunction being the most commonly encountered complication of distal biceps tendon reattachment¹⁷ especially in those utilising the single incision technique.²⁰The LABCN arises from the C5, C6 cervical roots and is a terminal sensory branch of the musculocutaneous nerve. Cadaveric studies have demonstrated that the LABCN emerges from the lateral margin of the biceps tendon, piercing the deep fascia between brachialis and biceps at the level of the elbow.^21,22 It has a close relationship with the cephalic vein running just medial to it at the elbow and continuing distally medially and parallel with the vein in the subcutaneous fat of the forearm.^21,22

Several patients in this study had long term dysesthesia in the distribution of the LABCN nerve. Previous case reports and case series have demonstrated LACBN entrapment between the biceps tendon and brachialis fascia^23,24 but intra-operative identification of the nerve ensured that this was not the case in our series.

Given the close anatomic relationship between the biceps and LACBN, we hypothesise that following biceps reattachment, scar tissue may place undue traction onto the nerve particularly at the extremes of movement during elbow extension and supination/pronation which may cause nerve symptoms.

Surgical decompression of the LACBN with improvements in symptoms has been reported in certain entrapment neuropathies^25,26 but optimal treatment for nerve dysfunction following distal biceps tendon surgery is not clear. Secondary analysis demonstrated markedly lower satisfaction scores in this group in our study highlighting the impact this may have on patient satisfaction following surgical reattachment. We believe patients should be adequately counselled regarding the potential for LACBN dysfunction and the impacts on outcomes.

Limitations of this study include its retrospective design which limited the availability of absolute tendon retraction measurements on ultrasound for some of the cases examined. Furthermore, the small number of cases treated at more than 7 weeks post injury limits any conclusions that can be made up to that time limit.

6. Conclusion

In conclusion, our results suggest that degree of radiological retraction and chronicity (up to 7 weeks) are not related to the ability to reattach distal biceps tendon ruptures or long-term clinical outcomes, hence should not discourage surgical exploration and attempted reattachment. Substantial tendon retractions can occur acutely, though reattachment in considerable flexion does not lead to demonstratable long-term extension loss. Some cases may need augmentation or gap bridging and therefore augmentation devices need to be available at surgery.

Declaration of competing interest

The authors declare no conflict of interest.