Abstract
Background
Modern distal biceps reconstruction techniques generally have satisfactory outcomes, but are not without complications. Posterior interosseous nerve (PIN) palsy is a rare but potentially devastating complication of bicortical metal button fixation. Recently, a unicortical, intramedullary, repair technique utilizing a suture anchor has been described. The primary aim of this study was to compare short-term functional and patient-reported outcomes and complication rates in patients receiving unicortical intramedullary repair (UR) with suture anchor against those receiving bicortical repair (BR) with metallic button. We hypothesized that UR would have equally satisfactory outcomes without the complication profile.
Methods
Retrospective chart review was conducted for all patients undergoing operative fixation of distal biceps tendon ruptures from 2015 to 2021 at our tertiary referral center. Twenty patients received BR, and eight patients received UR. Patient demographics and surgical complications were compared. QuickDASH scores at two-month and latest in-person and telehealth postoperative visits, as well as elbow and forearm range of motion at last clinical visit, were collected and analyzed.
Results
Average patient age in the BR & UR cohorts were 49.3 ± 9.3 and 42.1 ± 6.2 years, respectively, with a male predominance. There was no statistical difference in patient age, sex, hand dominance, injury laterality, injury chronicity, and follow-up duration. Range of motion was comparable and excellent in both groups. Latest follow-up was 3.0 ± 0.5 years in the BR and 1.5 ± 0.4 years in the UR cohorts. QuickDASH scores improved between the two-month and latest time points in each cohort however did not differ significantly in head-to-head comparison. Complications included a case of PIN palsy, distal biceps tendon rerupture, and lateral antebrachial cutaneous nerve (LABC) neuropraxia in the BR group and two cases of LABC neuropraxia in the UR group. The number needed to treat (NNT) for the prevention of one additional case of PIN palsy using UR is 22 patients.
Discussion
Short-term functional and patient-reported outcomes in traditional BR and newly reported UR of distal biceps tendon ruptures are comparable and excellent. UR did not have higher failure rate despite follow-up periods beyond what is typically reported for tendon reruptures. In this limited retrospective cohort study, UR also did not encounter postoperative PIN palsy and had an NNT of 22 patients. In the appropriate clinical setting, this provides early evidence supporting the utilization of unicortical intramedullary suture anchor fixation of distal biceps tendon ruptures as well as associated perioperative interventions such as preoperative nerve blocks.
Keywords: Distal, Biceps, Repair, Intramedullary, Unicortical, Outcome
Bicortical, metallic button fixation through the bicipital tuberosity is a well-characterized and popular technique for the repair of distal biceps tendon ruptures. Biomechanically, cortical button repair has been reported to achieve excellent fixation strength.3,12,15 Clinically, these procedures achieve satisfactory outcomes.9,10 Despite these advantages, a notable shortcoming of bicortical fixation is the risk of iatrogenic injury to the posterior interosseous nerve (PIN), which is reported to occur in approximately 1%-8% of cases.5,8,11,17 Techniques have been described to minimize this risk including drill trajectories within safer corridors and unicortical button fixation. It is noted however, that anatomic variations in the location of patients’ PIN unfortunately precludes complete avoidance of PIN palsy.2,14,18 Unicortical metallic button fixation has also been reported. Despite similar benefits and promising outcomes, intramedullary deployment within the unpredictable size of certain patients’ radial canal presents a challenge.16
To address these challenges, our group recently described a unicortical, intramedullary technique utilizing a suture anchor for distal biceps tendon repair.4 Outcomes for this procedure have, to date, not been described. The primary aim of this study was to compare short-term functional and patient-reported outcomes and complication rates in patients receiving unicortical intramedullary repair (UR) with suture anchor against those receiving bicortical repair (BR) with metallic button. We hypothesized that URs would have equally satisfactory outcomes without the complication profile.
Materials and methods
After obtaining institutional review board approval for this study, a retrospective chart review was conducted for patients who underwent repair for distal biceps tendon repair by two fellowship-trained orthopedic hand and upper extremity surgeons at our tertiary referral center (A.L. & B.T.B). Patient charts were identified by a search of Current Procedural Terminology code 24342 (reinsertion of ruptured distal biceps tendon) between January 2015 and June 2021. The exclusion criteria included triceps rupture, concomitant fracture or nerve injury at time of surgery, and follow-up duration shorter than six months. Patient demographics, operative technique, surgical complications, postoperative patient-reported outcomes (QuickDASH score), and range of motion were collected and analyzed. QuickDASH scores were obtained at both the two-month and latest in-person and telehealth postoperative visits.
Patients were separated into two cohorts based on their operative technique: Bicortical metallic button repair (BR) and unicortical intramedullary suture anchor repair. At our institution, BR was historically used for distal biceps repair. By the year 2019, the UR implant was introduced, tested in cadaveric settings, and ultimately adopted for clinical application in 2020. All subsequent distal biceps tendon repairs were performed using this technique by the surgeons in the current study (A.L. & B.T.B). All URs were performed based on our previously described technique.4 In brief, upon exposure of the radial tuberosity, a unicortical hole was drilled, followed by deployment of the intramedullary all-suture anchor. The two accompanying sutures were run through the biceps stump in a locked Krackow fashion, and then used to reduce and lock the tendon back to the radius.
Statistics were expressed as mean and standard deviations. Continuous outcome measures were assessed using t tests. Categorical outcomes were compared using chi-squared and exact tests of goodness-of-fit. P values of less than .05 were considered statistically significant. All statistical analyses were conducted utilizing SPSS Statistics (IBM Corp, Armonk, NY).
Results
From an initial query of 50 patients, thirteen were excluded as erroneously coded triceps ruptures, three were excluded for concomitant fracture, and six were excluded for follow-up duration shorter than six months. The final cohort comprised of 20 patients in the BR group and 8 patients in the UR group. Average patient age in the BR & UR cohorts were 49.3 ± 9.3 and 42.1 ± 6.2 years, respectively, with a male predominance. No statistically significant difference was found in patient age, sex, hand dominance, or injury laterality. Patients in both groups had comparable injury chronicity, both in relation to time between injury and initial presentation in clinic and between injury and date of surgery. Postoperative follow-up durations were also similar. Latest follow-up was 3.0 ± 0.5 years in the BR and 1.5 ± 0.4 years in the UR cohorts (Table I).
Table I.
Patient demographics, symptom, and follow-up duration.
| Bicortical metallic button (n = 20) | Unicortical suture anchor (n = 8) | P value | |
|---|---|---|---|
| Age (y) | 49.3 ± 9.3 | 42.1 ± 6.2 | .06 |
| Sex (M/F) | 19/1 | 8/0 | .52 |
| Hand dominance (R/L) | 16/3 | 7/1 | .83 |
| Injury laterality (R/L) | 9/10 | 4/4 | .90 |
| Time between injury & initial presentation (week) | 4.6 ± 8.1 | 3.2 ± 4.5 | .65 |
| Time between injury & surgery (week) | 7.8 ± 10.6 | 4.9 ± 6.0 | .47 |
| In-office follow-up duration (week) | 18.3 ± 9.6 | 12.7 ± 4.2 | .13 |
M/F, male/female; R/L, right/left.
Postoperative outcomes
At final follow-up, elbow and forearm range of motion was comparable and excellent in both BR and UR groups (Table II). Elbow flexion and extension as well as forearm supination and pronation were close to full in both cohorts. Generally, QuickDASH scores improved in both the BR and UR groups between the two-month and latest follow-up visits (22.5 ± 10.7 and 9.1 ± 13.7 at the two-month and latest follow-up visits, respectively for the BR group, P = .01; and 14.2 ± 10.9 and 2.6 ± 4.2 for the UR group, P = .03). With the available data, QuickDASH scores were improved in the UR cohort at both time points; however, the difference was not statistically significant.
Table II.
Postoperative outcomes and complications.
| Bicortical metallic button (n = 20) | Unicortical suture anchor (n = 8) | P value | |
|---|---|---|---|
| 2-mo QuickDASH | 22.5 ± 10.7 | 14.2 ± 10.9 | .08 |
| Latest QuickDASH | 9.1 ± 13.7 | 2.6 ± 4.2 | .38 |
| Change in QuickDASH | −13.4 ± 11.7 | .01 | |
| −11.6 ± 8.8 | .03 | ||
| Final flexion (degrees) | 135.5 ± 5.4 | 139.4 ± 5.6 | .10 |
| Final extension (degrees) | 3.0 ± 7.3 | 1.3 ± 3.5 | .53 |
| Final supination (degrees) | 69.0 ± 6.8 | 64.4 ± 16.1 | .29 |
| Final pronation (degrees) | 70.3 ± 8.2 | 70.0 ± 11.7 | .95 |
| Complications (number) | |||
| PIN palsy | 1 | 0 | |
| Rerupture | 1 | 0 | |
| LABC neuropraxia | 1 | 2 |
PIN, posterior interosseous nerve; LABC, lateral antebrachial cutaneous nerve.
Complications
In the BR cohort, three separate patients sustained postoperative PIN palsy, rerupture, and LABC neuropraxia. Patients in the UR cohort did not experience PIN palsy; however two had LABC neuropraxia (Table II). The number needed to treat (NNT) for the prevention of one additional case of PIN palsy using UR is 22 patients.
Discussion
In the current retrospective cohort study, short-term outcomes of UR were comparable to that of BR, without the risk of PIN injury. Patients with UR were able to achieve postoperative elbow and forearm range of motion at the same level with that of BR counterparts. At eighteen months to three years postop, patient-reported QuickDASH scores in the UR cohort was 3.2 ± 4.4. This, as well, was not inferior to patients with BR. Notably, PIN injury was not encountered in patients receiving UR. Based on this limited study therefore, the NNT (ie. the number of patients needed to be treated to prevent one additional negative outcome) for the prevention of one additional case of PIN palsy using UR is 22 patients. This finding is not surprising as it has been hypothesized that direct injury, owing to dorsal radial cortex penetration of drills, guidewires, and implants in traditional bicortical fixation is the main culprit of PIN palsy. Despite generally satisfactory functional and patient-reported outcomes using BR in the literature, the incidence of PIN palsy has been reported to range from 1% to 8%.5,8,11,17 In addition to comparable clinical outcomes, UR with suture anchor’s ability to reliably avoid PIN injury, has the potential to benefit other areas of clinical practice including safely utilizing preoperative nerve blocks for patient analgesia.
At latest follow-up, no tendon reruptures were encountered in the UR group. While this is almost certainly a reflection of limited sample size, it is reassuring that the follow-up duration for the UR group in the current study is well beyond what is reported as the time frame for most reruptures to occur. Previous studies examining metallic button fixation of distal biceps tendon ruptures have described that rerupture most frequently occurs within the first two months of surgery.1,7,10 The novelty of the current intramedullary suture anchors utilized in this study however renders conclusions regarding clinical rerupture rate inconclusive at the present time.
The authors acknowledge several important methodological limitations to the current study. Most importantly, the sample size in both cohorts is limited as a result of the rarity of this injury. The current study does not have sufficient power to detect differences in outcome, and thus conclusions drawn to date must be taken in an observational context. Comparison of the rate of PIN palsy, in particular, would benefit from larger analyses. Despite promising early results, follow-up studies will be required to provide long-term outcomes of UR for distal biceps tendon ruptures with a particular interest in rerupture rates. Utilization of the same implant for subpectoral biceps tenodesis indications has shown ultimate failure loads commensurate with that of metallic button fixation.13 A recent biomechanical comparison between intramedullary all-suture anchors and bicortical metallic button anchors has also found equivalent maximum load to failure and lower maximum displacement with the all-suture anchor, albeit with a dual-suture-anchor construct.6 The current study also did not have the sufficient data to compare other outcome measures of-interest, including but not limited to elbow flexion, forearm supination strength, and endurance. Finally, this study was also performed at a single institution, with two surgeons’ patients, which may limit the generalizability of these findings. Even among unicortical suture anchor fixation, there exist implant- and provider-dependent technique variations, such as the use of single versus double-loaded sutures to reinforce fixation, which may confound outcomes.19
Conclusion
Short-term observational results from this study support unicortical, intramedullary suture anchors as a promising alternative for repair of distal biceps tendon ruptures. Functional and patient-reported outcomes are comparable with commonly used bicortical, metallic button fixation without associated risk of PIN injury. Further investigation is required to determine long-term viability and any complications unique to this treatment technique.
Disclaimers
Funding: No funding was disclosed by the authors.
Conflicts of interest: Adrienne Lee and Blaine Todd Bafus have received financial support for education and food & beverage from Rock Medical Orthopedics, Inc. The other authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
Footnotes
MetroHealth Medical Center institutional IRB approval was obtained prior to conducting the current study (IRB ID: STUDY00000067).
References
- 1.Amarasooriya M., Bain G.I., Roper T., Bryant K., Iqbal K., Phadnis J. Complications after distal biceps tendon repair: a systematic review. Am J Sports Med. 2020;48:3103–3111. doi: 10.1177/0363546519899933. [DOI] [PubMed] [Google Scholar]
- 2.Bain G.I., Prem H., Heptinstall R.J., Verhellen R., Paix D. Repair of distal biceps tendon rupture: a new technique using the Endobutton. J Shoulder Elbow Surg. 2000;9:120–126. [PubMed] [Google Scholar]
- 3.Chavan P.R., Duquin T.R., Bisson L.J. Repair of the ruptured distal biceps tendon: a systematic review. Am J Sports Med. 2008;36:1618–1624. doi: 10.1177/0363546508321482. [DOI] [PubMed] [Google Scholar]
- 4.Cheng C., Bafus B.T. Intramedullary, unicortical repair of distal biceps tendon rupture. JSES Rev Rep Tech. 2022;2:238–242. doi: 10.1016/j.xrrt.2021.12.002. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Chillemi C., Marinelli M., De Cupis V. Rupture of the distal biceps brachii tendon: conservative treatment versus anatomic reinsertion - clinical and radiological evaluation after 2 years. Arch Orthop Trauma Surg. 2007;127:705–708. doi: 10.1007/s00402-007-0326-7. [DOI] [PubMed] [Google Scholar]
- 6.Colantonio D.F., Le A.H., Keeling L.E., Slaven S.E., Vippa T.K., Helgeson M.D., et al. Intramedullary unicortical button and all-suture anchors provide similar maximum strength for onlay distal biceps tendon repair. Arthroscopy. 2022;38:287–294. doi: 10.1016/j.arthro.2021.06.036. [DOI] [PubMed] [Google Scholar]
- 7.Ford S.E., Andersen J.S., Macknet D.M., Connor P.M., Loeffler B.J., Gaston R.G. Major complications after distal biceps tendon repairs: retrospective cohort analysis of 970 cases. J Shoulder Elbow Surg. 2018;27:1898–1906. doi: 10.1016/j.jse.2018.06.028. [DOI] [PubMed] [Google Scholar]
- 8.Gallinet D., Dietsch E., Barbier-Brion B., Lerais J.M., Obert L. Suture anchor reinsertion of distal biceps rupture: clinical results and radiological assessment of tendon healing. Orthop Traumatol Surg Res. 2011;97:252–259. doi: 10.1016/j.otsr.2010.11.010. [DOI] [PubMed] [Google Scholar]
- 9.Grewal R., Athwal G.S., MacDermid J.C., Faber K.J., Drosdowech D.S., El-Hawary R., et al. Single versus double-incision technique for the repair of acute distal biceps tendon ruptures: a randomized clinical trial. J Bone Joint Surg Am. 2012;94:1166–1174. doi: 10.2106/JBJS.K.00436. [DOI] [PubMed] [Google Scholar]
- 10.Huynh T., Leiter J., MacDonald P.B., Dubberley J., Stranges G., Old J., et al. Outcomes and complications after repair of complete distal biceps tendon rupture with the cortical button technique. JB JS Open Access. 2019;4:e0013.1–e0013.6. doi: 10.2106/jbjs.oa.19.00013. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Kelly E.W., Morrey B.F., O’Driscoll S.W. Complications of repair of the distal biceps tendon with the modified two-incision technique. J Bone Joint Surg Am. 2000;82:1575–1581. doi: 10.2106/00004623-200011000-00010. [DOI] [PubMed] [Google Scholar]
- 12.Kettler M., Lunger J., Kuhn V., Mutschler W., Tingart M.J. Failure strengths in distal biceps tendon repair. Am J Sports Med. 2007;35:1544–1548. doi: 10.1177/0363546507300690. [DOI] [PubMed] [Google Scholar]
- 13.Lacheta L., Rosenberg S.I., Brady A.W., Dornan G.J., Millett P.J. Biomechanical comparison of subpectoral biceps tenodesis onlay techniques. Orthop J Sport Med. 2019;7 doi: 10.1177/2325967119876276. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Lo E.Y., Li C.S., Van Den Bogaerde J.M. The effect of drill trajectory on proximity to the posterior interosseous nerve during cortical button distal biceps repair. Arthroscopy. 2011;27:1048–1054. doi: 10.1016/j.arthro.2011.03.084. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Mazzocca A.D., Burton K.J., Romeo A.A., Santangelo S., Adams D.A., Arciero R.A. Biomechanical evaluation of 4 techniques of distal biceps brachii tendon repair. Am J Sports Med. 2007;35:252–258. doi: 10.1177/0363546506294854. [DOI] [PubMed] [Google Scholar]
- 16.Monaco N.A., Duke A.J., Richardson M.W., Komatsu D.E., Wang E.D. Distal biceps repair using a unicortical intramedullary button technique: a case series. J Hand Surg Glob. 2019;1:178–184. doi: 10.1016/j.jhsg.2019.03.003. [DOI] [Google Scholar]
- 17.Nigro P.T., Cain R., Mighell M.A. Prognosis for recovery of posterior interosseous nerve palsy after distal biceps repair. J Shoulder Elbow Surg. 2013;22:70–73. doi: 10.1016/j.jse.2012.08.001. [DOI] [PubMed] [Google Scholar]
- 18.Thumm N., Hutchinson D., Zhang C., Drago S., Tyser A.R. Proximity of the posterior interosseous nerve during cortical button guidewire placement for distal biceps tendon reattachment. J Hand Surg Am. 2015;40:534–536. doi: 10.1016/j.jhsa.2014.10.039. [DOI] [PubMed] [Google Scholar]
- 19.Wörner E., van Oost I., Eygendaal D., The B. Higher failure rate of suture anchors in partial distal biceps tendon ruptures in comparison with Endobutton fixation. JSES Int. 2021;5:821–826. doi: 10.1016/j.jseint.2021.02.012. [DOI] [PMC free article] [PubMed] [Google Scholar]