The clinical and radiologic outcome of microfracture on arthroscopic repair for full-thickness rotator cuff tear

J Shoulder Elbow Surg (2019) -, 1–6

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The clinical and radiologic outcome of microfracture on arthroscopic repair for full-thickness rotator cuff tear Anil Pulatkan, MDa, Wasim Anwar, MDb, Sevil Tokdemir, MDc, Sercan Akpinar, MDd, Kerem Bilsel, MDa,* _ Department of Orthopedics and Traumatology, School of Medicine, Bezmialem Vakif University, Istanbul, Turkey FCPS Department of Orthopedics, Medical Teaching Institute, Hayatabad Medical Complex, Peshawar, Pakistan c _ Department of Radiology, School of Medicine, Bezmialem Vakif University, Istanbul, Turkey d Medline Adana Hastanesi, Belediye Evleri Mahallesi, C¸ ukurova, Adana, Turkey a b

Background: The persistent incidence of retear despite improvements in techniques led orthopedic surgeons to the application of principles of tissue bioengineering to achieve enhanced repair and functional outcomes. The purpose of this study was to compare clinical and radiologic outcomes of arthroscopic single-row repair augmented with microfracture (SRM) at the greater tuberosity with single-row (SR) and double-row (DR) repair in the treatment of full-thickness rotator cuff tears. Materials and methods: This is a retrospective comparative study. A total of 123 patients were enrolled for arthroscopic repair of full-thickness rotator cuff tears, with 40 patients treated by SR, 44 by SRM, and 39 by DR. The minimum follow-up was 2 years. The primary outcome was retear rate, which was detected by magnetic resonance imaging, and the secondary outcome was functional outcome. Results: The mean age of the patients was 59.2 years, 58.1 years, and 60.6 years in the SR, SRM, and DR groups, respectively. The retear rate was 33%, 14%, and 36% in the SR, SRM, and DR groups, respectively (P ¼ .045). The SRM group had significantly improved functional outcomes compared with the SR and DR groups in terms of the postoperative Constant score and visual analog scale score (P ¼ .001 and .002, respectively). Delta Constant scores were nonsignificant for retear and intact tendons (P ¼ .137). Conclusion: SRM has a significantly lower retear rate and better functional outcome than SR and DR repair. Levels of evidence: Level III; Retrospective Cohort Design; Treatment Study Ó 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. Keywords: Single-row; double-row; augmentation; microfracture; retear; rotator cuff repair

This study was approved by the Bezmialem Institutional Review Board (no. 45446446-020-17306). All of the patients provided written informed consent for inclusion in the study.

*Reprint requests: Kerem Bilsel, MD, Department of Orthopedics and Traumatology, School of Medicine, Bezmialem Vakif University, Vatan _ Cd, Fatih 34093, Istanbul, Turkey. E-mail address: [email protected] (K. Bilsel).

1058-2746/$ - see front matter Ó 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved. https://doi.org/10.1016/j.jse.2019.07.010

2 Arthroscopic rotator cuff repair has encouraging results with advancing technologies and skills; still, the recurrence rate is as high as 90%.2,4,12,26,27 Maintaining the biomechanics and maximizing the tendon to bone healing, the techniques evolved from single-row (SR) to double-row (DR) to transosseous equivalents to suture bridging techniques and, finally, to augmentation procedures.7,12,24 The development of newer suture anchors has allowed surgeons to efficiently achieve these goals. Whereas biomechanical studies support the evolution techniques, clinical trials remain inconclusive.28 A literature review demonstrated no significant difference in outcome between arthroscopic SR repair and DR repair, but arthroscopic repair with augmentation procedures showed excellent results.6,7,12,24,28 However, limited data are available in the literature about the clinical outcome of arthroscopic repair with augmentation procedures. Therefore, the purpose of this study was to compare clinical and radiologic outcomes of arthroscopic SR repair augmented with microfracture (SRM) at the greater tuberosity with SR repair and DR repair in the treatment of fullthickness rotator cuff tears.

Materials and methods This single-center retrospective comparative study was conducted from August 2014 to August 2017 in the Department of Orthopedics and Traumatology of Bezmialem Vakif University (Istanbul, Turkey) for arthroscopic repair of fullthickness rotator cuff tears. The hospital data, patient records, and operative reports were reviewed to confirm age, sex, clinical examination, preoperative imaging, diagnosis, date of operation, surgical repair techniques, intraoperative videos and findings, and surgical time. The preoperative shoulder Constant score and visual analog scale (VAS) score were reviewed. Tear size was determined from preoperative magnetic resonance imaging (MRI) and arthroscopic findings as well as from video recordings. Patients with failure of conservative treatment for a minimum of 6 weeks as well as patients with degenerative and traumatic full-thickness tears primarily repaired, which are classified as large tears according to the Cofield classification, were included in the study.5 Excluded from the study were patients with partial, small, medium, or massive retracted tears; patients with revision of rotator cuff repair, cuff tear arthropathy, associated anterior instability, or subscapularis tear; patients with <2 years of followup; and patients who were lost to follow-up. Three groups of patients were clinically and radiologically evaluated: group SR, single-row arthroscopic rotator cuff repair; group SRM, single-row arthroscopic rotator cuff repair with microfracture at the greater tuberosity to augment healing; and group DR, double-row arthroscopic rotator cuff repair. A priori statistical power analysis was performed to calculate the sample size. A difference of a mean of 5  8 points in the shoulder Constant score was defined as the minimal clinically relevant difference.16 With a power of 80%, a 95% confidence level, and an a value of .05, the results of the power analysis determined a sample size of 39 in each group.

A. Pulatkan et al. There were 355 shoulder arthroscopy patients reviewed. Of 355 shoulders, we excluded 42 shoulder instability cases, 6 subscapularis tears, 21 partial-thickness tears, 43 small tears, 47 medium tears, 29 massive cuff tears, 27 cuff tear arthropathy cases, 10 revision arthroscopy cases, and 7 patients who were lost to follow-up. A total of 123 patients met our inclusion and exclusion criteria. A total of 40, 44, and 39 patients in the SR, SRM, and DR groups, respectively, were enrolled in the study. The surgical technique was selected by the senior surgeon according to his experience and preference independent of patient parameters without any randomization method. These patients were called, the aims and scope of the study were explained, and the patients received additional information about clinical scoring systems and MRI and magnetic resonance arthrography as well as about contrast material. The primary outcome was the detection of a retear on MRI among the 3 different techniques. We graded tendon status at 1year postoperative follow-up using the Sugaya classification23 (Table I). A tendon with an intact repair was defined as Sugaya type I-III (Fig. 1). A tendon with a failed repair or retear was defined as Sugaya type IV or type V (Fig. 2). MRI was evaluated by 2 senior orthopedic surgeons and 1 radiologist in a consensus. If there was no consensus among the evaluators, the opinion of the majority was taken as basis. Comparisons were performed among the groups, and individuals were compared between the groups for retear rate. The secondary outcome was assessed with the shoulder Constant score and VAS score. The secondary outcome was recorded both preoperatively and postoperatively. The difference between the preoperative and postoperative shoulder Constant score was calculated as a delta Constant score. The results of the patients among the groups were compared at final follow-up. Retears and intact tendons were compared with the delta Constant score and VAS score for functional outcome at final follow-up.

Surgical technique All procedures were performed in the beach chair position. The patient was scrubbed and draped. Preoperative skin marking was done. A standard posterior portal was created, and a 30 arthroscope was inserted for visualization. An anterior portal was created under direct visualization with a spinal needle in the rotator interval, and diagnostic arthroscopy was performed. The tear was visualized and confirmed from the articular side. Biceps tenotomy or tenodesis was performed according to the age and preoperative findings of biceps tendon integrity. The arthroscope was then moved to the subacromial space, and a lateral portal was created under visualization; subacromial decompression and bursectomy were performed through the lateral portal with the help of a radiofrequency ablation device and arthroscopic shaver, and the subacromial space was visualized. The rotator cuff tear was reidentified from the bursal side, the edges were refreshed, and the tissues were mobilized and released to obtain tension-free restoration of the anatomic footprint. The greater tuberosity at the footprint was slightly decorticated. An anterolateral accessory portal was created for anchor placement and suture management. Two double-loaded suture anchors were used in all patients, and 2 additional knotless anchors were added in the standard transosseous-equivalent technique for the DR group. The rotator cuff was repaired by SR alone, SRM, or DR according to the

Microfracture on rotator cuff repair

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Table I

Classification of postoperative rotator cuff integrity (described by Sugaya et al23)

Type

Definition of type

I II III

Sufficient thickness compared with that of the normal cuff and homogeneously low intensity Sufficient thickness compared with that of the normal cuff and partial high intensity Insufficient thickness (less than half the thickness of the normal cuff) but discontinuity, suggesting a partial-thickness delaminated tear Presence of a minor discontinuity in 1-2 slices on both oblique coronal and sagittal images, suggesting a small full-thickness tear Presence of a major discontinuity in more than 2 slices on both oblique coronal and sagittal images, suggesting a medium or large full-thickness tear

IV V

performed using the Mann-Whitney test and independent samples t-test, and 3-group comparisons were performed using the Kruskal-Wallis and one-way analysis of variance tests. Categorical comparisons were performed using the Fisher exact and Fisher-Freeman-Halton tests. Continuous variables were expressed with median (minimum-maximum) and mean  standard deviation values, and categorical variables were expressed with frequency (percentage) values. The results are reported as 95% confidence intervals and related P values. All analyses were done using SPSS version 21 software (IBM, Armonk, NY, USA). P < .05 was considered statistically significant.

Results

Figure 1 type I).

Regenerated footprint at 1-year follow-up (Sugaya

preoperative findings and the surgeon’s preference. In the SRM group, SR repair was done in standard fashion, and a custom-made awl (Tasarım Medikal, Istanbul, Turkey) with a straight trihedral cutting tip was used to perform microfracture to penetrate subchondral bone. The holes are standardized as 1.3-mm diameter, 4to 5-mm distance, and 5-mm depth to the lateral side of the repair zone in the greater tuberosity (Fig. 3).

Follow-up protocol All the patients were followed up at 2 weeks, 4 weeks, 2 months, 6 months, and 1 year. Patients were immobilized in 30 of abduction for 4 weeks. Passive range of motion started at 4-6 weeks, and active range of motion started in 2 months.

Statistical analysis Concordance of the continuous data to normal distribution was tested by the Shapiro-Wilk test. Two-group comparisons were

The mean age of the patients was 59.2 years, 58.1 years, and 60.6 years in the SR, SRM, and DR groups, respectively. There were no significant differences among the 3 groups in terms of age, sex, dominant side, history of trauma, and preoperative Constant score. None of the patients had reported a trauma at the routine postoperative controls. There was a significant difference in the time before surgery and the preoperative steroid injections among the groups; patients in the DR group had longer duration of symptoms and more steroid injections preoperatively (Table II). When functional outcomes of the groups were compared, there was a significant difference in terms of postoperative shoulder Constant score and delta Constant score. The delta Constant scores were 26.4, 30.4, and 19.1 in the SR, SRM, and DR groups, respectively (P < .001). Comparisons between individual groups in terms of the postoperative Constant score showed no difference between the SR and SRM groups or between the SR and DR groups, but there was a significant difference between the SRM and DR groups. Among the SR, SRM, and DR groups, there was a significant difference in both the Constant score and the VAS score. The rotator cuff retear rate was 33%, 14%, and 36% in the SR, SRM, and DR groups, respectively (P ¼ .045). On individual analysis between groups, there was a significant difference of SR vs. SRM and SRM vs. DR (P ¼ .039 and .018, respectively); however, there was no significant difference between the SR and DR groups in terms of the

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Figure 3 To stimulate the bone marrow, microfracture is performed before rotator cuff repair.

Figure 2 type V).

Retear of rotator cuff after 1-year follow-up (Sugaya

retear rate. Retear had no effect on the functional outcome; when patients in the retear group were assessed against functional outcome (delta Constant score), there was no significant difference in the functional outcome of patients with intact tendons compared with patients with ruptured tendons (P ¼ .137). At final follow-up, the retear rate, postoperative shoulder Constant score, and VAS score were assessed (Table III).

Discussion The challenging issues surrounding rotator cuff surgery are the restoration of the anatomic footprint, tendon to bone fixation, and failure of healing. Retear is the most frequently encountered complication of rotator cuff surgery.2,4,12,26,27 Comparison of the 3 arthroscopic rotator cuff repair techniques demonstrated a statistically significant decrease in the retear rate in patients treated with SRM at the greater tuberosity. Biomechanical studies have shown the superiority of the DR repair technique over the SR repair technique.9,11,14,22 However, clinical studies have failed to verify this superiority.8,17,19-21 Despite the biomechanical and technical improvements in rotator cuff techniques with relatively good functional outcomes, to an extent, this led researchers to integrate the augmentation procedure around tendons and bones to

achieve excellent tendon to bone healing and to lower the retear rate.18 Biologic growth factors, platelet-rich plasma, augmentation grafting techniques (with allogenic or autologous graft), suture augmentation techniques, and augmentation with microfracture at the greater tuberosity have been introduced with some promising biomechanical advantages, but some of them are technically demanding and have not yet been transferred into regular clinical practice1,7,12,13,15,25; however, SRM at the greater tuberosity gained popularity because of the simplicity of the procedure. The biology of the repair is enhanced with bone marrow vents created by microfractures of the greater tuberosity, forming the ‘‘crimson duvet’’ or bone marrow superclot, which will envelop the repair site and regenerate the footprint of the rotator cuff.7,13 In comparing our results with those of other studies in the literature for our primary outcome of retear rate, it has been found that SRM at the greater tuberosity has a lower incidence of retear rate than SR repair alone and DR repair.6,7,10,13 Our previous experimental animal study showed significant dynamic tendon healing in microfracture on the tuberosity of the repaired chronic rotator cuff tear.3 Milano et al,13 in a prospective randomized study, demonstrated that the tendon healing rate was 52.6% in patients in the SR group and 65.7% in a group of patients treated with SRM at the greater tuberosity, with a significant difference between groups. Dierckman et al,6 in a retrospective study, demonstrated that arthroscopic repair of a medium to large rotator cuff tear using a triple-loaded SR repair augmented with bone marrow vents resulted in a 91% healing rate according to MRI and an excellent clinical outcome. Jo et al,10 in a cohort study, showed a lower

Microfracture on rotator cuff repair Table II

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Patients’ demographic and baseline clinical characteristics

Age (yr) Sex, male/female Dominant side, right/left History of trauma Preoperative steroid injection Time before surgery (mo) Biceps tenotomy Biceps tenodesis Acromioplasty Intraoperative pullout Preoperative Constant score Follow-up (mo)

Single-row repair (n ¼ 40)

Single-row repair with microfracture (n ¼ 44)

Double-row repair (n ¼ 39)

P value

59.2  10.1 15/25 28/12 4 (10) 23 (58) 17.6  33.2 26 (65) 6 (15) 34 (85) 2 (5) 49.1  6.4 30 (26-48)

58.1  9.7 11/33 33/11 7 (16) 15 (34) 10  7.6 29 (66) 5 (11) 33 (75) 2 (5) 49.5  10.7 30 (26-48)

60.6  9.8 11/28 31/8 8 (21) 24 (62) 32  48.1 25 (64) 4 (10) 29 (74) 0 (0) 51.9  6.5 29 (27-37)

.517* .438y .624y .431y .024y .011* .985y .834y .432y .546y .257* .252z

Categorical variables are presented as number (%). Continuous variables are presented as mean  standard deviation. Bold values are considered statistically significant. * One-way analysis of variance. y Fisher-Freeman-Halton test. z Kruskal-Wallis test.

Rotator cuff integrity (according to Sugaya’s grading23), VAS score, and Constant score at final SR (n ¼ 40) SRM (n ¼ 44) DR (n ¼ 39) P value*,y,z SR vs. SRM Retear 13 (33) 6 (14) 14 (36) .045* .039 VAS score for pain 3 (1-8) 2 (1-7) 3 (1-7) .002y .03 Postoperative Constant score 75.5  12.5 79.8  8.4 71  10.9 .001z .150 Delta Constant 26.4  12.3 30.4  12.2 19.1  12.6 <.001z .304 Table III

follow-up SR vs. DR

SRM vs. DR

.750 .143 .156 .04

.018 <.001 .001 <.001

VAS, visual analog scale; SR, single-row repair; SRM, single-row repair augmented with microfracture; DR, double-row repair. Categorical variables are presented as number (%). Continuous variables are presented as median (minimum-maximum) or mean  standard deviation. Bold values are considered statistically significant. * Fisher-Freeman-Halton test. y Kruskal-Wallis test. z One-way analysis of variance.

retear rate of 22.2% in the multiple channeling group, probably by the recruitment of endogenous mesenchymal stem cells and the proximal humerus, as well as a retear rate of 45.2% using the conventional technique, but this group did not show any significant difference in terms of functional outcome. Osti et al,16 in a prospective randomized controlled trial, reported that microfracture at the footprint is effective in the short term but failed to show any significant difference in the long term, both clinically and radiologically. There are several limitations and shortcomings of the study. This was a retrospective study with a short follow-up of 2 years. There was no randomization, which introduces selection bias for the surgeon based on surgical method decision-making. Patients in the DR repair group had a longer duration of symptoms and more steroid injections preoperatively compared with patients in the other groups. In the interpretation of MRI, the radiologist and orthopedic surgeons cannot be fully blinded because of the presence of the suture anchor and microfracture at the tuberosity.

Conclusion SRM is a safe, easy, effective technique and has the potential advantage of biologic healing at the footprint. SRM has a significantly lower retear rate and better functional outcome than SR and DR repairs alone. On the basis of our results, a future large prospective randomized controlled trial or systematic meta-analysis is recommended.

Disclaimer The authors, their immediate families, and any research foundations 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

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