36 A Comparison of the Outcomes of Two Types of Synthetic Patches for Interpositional Graft Use in Irreparable Rotator Cuff Tears

Tom Morrison, Patrick H. Lam, and George A.C. Murrell

Summary

Arthroscopic sutureanchor repair of massive rotator cuff tears has met limited success. The use of interpositional synthetic patch grafts has shown potential in recent studies with small sample sizes. The aim of this study was to evaluate the outcomes of interpositional synthetic patches for massive rotator cuff tear in a large cohort of patients. We identified 69 patients with large and irreparable rotator cuff tears who underwent arthroscopic interpositional patch repair with ePTFE (38 patients) or PTFE felt (26 patients) synthetic patches. This cohort was matched in terms of anteroposterior, mediolateral, and total area tear dimensions with 100 patients who underwent arthroscopic rotator cuff repair using direct suture-anchor repair. Strength and range of motion were recorded at 1, 6, and 12weeks and 6months postsurgery. Repair integrity was evaluated via ultrasound at 6months postsurgery. Re-tear rates in the synthetic patch groups were lower than the suture-anchor group at 6 months (PTFE felt 4%, ePTFE 3% vs. sutureanchor repair 25%, p < 0.01). Supraspinatus strength in the PTFE felt repair group was greater than the sutureanchor repair group at 6 weeks (22N vs. 10N, p=0.01). All other functional outcomes were similar between the two groups. Patients receiving synthetic patches for massive and irreparable rotator cuff tears had significantly lower re-tear rates than those repaired using sutureanchor techniques and supraspinatus strength at 6 months postsurgery.

Keywords: arthroscopy, ePTFE patch, massive rotator cuff tear, polyterafluoroethylene patch, synthetic patch

36.1 Introduction

? Rotator cuff tears can be repaired by reattaching the torn tendon back to the humeral head using suture anchors. This approach has good outcomes for patients with small-to-moderate tears; however, the reported re-tear rate for repair of massive rotator cuff tears is between 20% and 90%.1

? Furthermore, so-called irreparable tears cannot be repaired with this technique because of retraction of the tendon. Treatment options for these tears include debridement, partial repair, or tendon transfer; however, the outcomes of these procedures have often been unsatisfactory.2

? We have developed a technique for arthroscopic rotator cuff repairs using synthetic patches for massive tears not amenable to direct repair. The results have been encouraging in studies with small sample sizes.3

? In this study, we compare PTFE felt (Bard PTFE felt, C.R. Bard, Warwick, RI) with ePTFE (Gore-Tex Expanded PTFE Patch, W.L. Gore and Associates, Newark, DE). ePTFE differs from PTFE felt as it is stretched under high temperatures. Both devices are designed to produce micropores that allow for tissue ingrowth when implanted. No previous studies have compared results of different patch materials.

? The aim of this study, therefore, is to compare outcomes of ePTFE and PTFE felt interpositional patches with standard sutureanchor only repair for massive rotator cuff tear in a large cohort. It was hypothesized that synthetic patch repairs would have lower rates of re-tear and better functional outcomes than direct suture-anchor repairs.

36.2 Methods

36.2.1 Study Design

? Following ethics approval (HREC 12/310), a retrospective study with prospectively collected data was undertaken. Patients were considered for inclusion in the study if they had received rotator cuff repair surgery by the senior author with an ePTFE (Gore-Tex Expanded PTFE Patch) or PTFE felt (Bard Expanded PTFE felt) interpositional patch rotator cuff repair, or a direct suture-anchor repair. Patients were excluded if they had severe arthritis, lymphedema, humeral head fractures, previous shoulder arthroplasty, or did not receive an ultrasound to evaluate repair integrity 6 months postsurgery.

? Three patient groups were compared, those receiving PTFE felt interpositional synthetic patches (PTFE felt group, n=26), those receiving ePTFE patches (ePTFE group, n=39), and those receiving sutureanchor repairs (direct repair group, n=100). The direct repair group was selected to compare the efficacy of the patch procedure with suture-anchor repairs. Patients in the direct repair group were selected if they had had a suture-anchor repair performed by the senior author between the date of the first and last patch operation, with anteroposterior, mediolateral, and total area of tear size being no larger or smaller than that of patch repairs. Posthoc matching occurred, as outlined in the results section, to ensure the direct-repair group was similar to the patch groups with respect anteroposterior, mediolateral, and total area of tear size.

36.2.2 Surgical Procedures

? Prophylactic antibiotics (cephalosporin) were administered preoperatively and 4hours postoperatively.

? All patients underwent arthroscopic rotator cuff repair in the beachchair position following interscalene regional anesthesia. The shoulder, arm, and hand were prepared with iodine solution and then draped. A standard posterior portal was made to allow for the arthroscope to be positioned within the posterior glenohumeral joint capsule.

? A second lateral incision was made superior to the superior border of the supraspinatus tendon to be used for the insertion of instruments, sutures, anchors, and a patch if required. This incision was made using a spinal needle to approximate the midpoint between the anterior and posterior edges of the tear.

? Once visualized, the edges of the cuff were lightly debrided using a 4- or 5-mm soft tissue shaver (Stryker Endoscopy, San Jose, CA). Debridement allowed for visualization of tear size, and determination of tendon quality and degree of tendon retraction. Patch repairs were indicated when the tendon could not be mobilized to the footprint on the humeral head, with other tears repaired using the direct suture-anchor technique.

? For a direct suture-anchor repair, the torn edge of the rotator cuff tendon was grasped with an Opus SmartStitch suturing device. A #2 braided polyethylene suture (MagnumWire) was deployed through the tendon body in an inverted mattress configuration, using either an Opus M-Connector or Perfect Passer (ArthroCare Sports Medicine, Sunnyvale, CA). A hole was made with a T-handle punch on the lateral margin of the rotator cuff footprint of the humeral head. The suture was passed through an Opus Magnum Knotless Implant anchor, which was secured into the hole using a single row configuration. Additional sutures and anchors were placed depending on the size of the tear.

? In the case of a patch repair, a patch was cut to a size large enough to bridge the defect while also allowing for 1.5 cm of overlap on the medial edge to account for suture overlap caused by the suture delivery device. The choice of patch material (between PTFE felt and ePTFE) was determined based upon current supplies at the surgical facility. The repair technique was the same for both patches. The medial edge of the patch was prepared first, with a Perfect Passer or M-Connector used to deliver sutures along the edge of the torn tendon in evenly dispersed 5 mm intervals. These sutures are were passed exvivo into the patch and evenly spaced using a Perfect Passer suture passer.

? The patch was secured to the torn edge of the rotator cuff using either the mattress or weave technique, as outlined by Shepherd et al3,4 The patch was then pushed through the lateral portal until it was situated within the glenohumeral joint. A knot pusher was used to push the patch toward the tendon so that the two surfaces were carefully opposed. The free ends of the tendon edge sutures were then tied arthroscopically, and loose ends trimmed with a suture cutter. To secure the patch to the humeral head, three sutures were passed through the edge of the patch using an Opus SmartStitch device (ArthroCare, Sydney, Australia) prior to patch insertion. A T-handled punch was used to create a hole on the greater tuberosity for the anterior anchor. The suture ends were passed through an Opus Magnum 2 suture anchor (ArthroCare). The anchor was placed into the holes in the greater tuberosity, and the suture tightened to reattach the patch to the footprint. The process was repeated for the medial and posterior suture.

? Portals were closed using uninterrupted nylon sutures and steristrips.

? All patients were rehabilitated in the same manner used for a typical rotator cuff repair. The arm was placed in a sling with a small abduction pillow (UltraSling II, DJO, Normanhurst, Australia) for 6 weeks. Patients initially completed pendulum exercises and 2 weeks postoperatively were introduced to passive flexion and extension range-of-motion exercises. At a 6-week postoperative physiotherapy visit, patients initiated active range-of-motion and isometric strengthening exercises. At 12 weeks postoperation, patients proceeded to overhead activates and lifting weights < 5 kg. At 6 months postoperation, patients returned to normal activities (? Video 36.1).

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Video 36.1 Surgical demonstration of a comparison of the outcomes of two types of synthetic patches for interpositional graft use in irreparable rotator cuff tears.

36.2.3 Patient-Ranked Outcomes

All patients completed a modified L?Insalata questionnaire evaluating pain at rest, during sleep, and during specific activities as well as shoulder stiffness and sporting and work activity using a Likert scale preoperatively and postoperatively at 1, 6, and 12 weeks and 6 months.5

36.2.4 Examiner-Ranked Outcomes

? All patients underwent a shoulder examination consisting of passive range-of-motion and strength testing. Forward flexion, abduction, external rotation, and internal rotation were tested and determined by visual inspection.6 Strength was tested using a handheld dynamometer upon adduction, internal rotation, lift off, external rotation, and abduction.7

? The integrity of the rotator cuff was determined at 6 months postoperation using a General Electric Logiq E9 ultrasound machine (GE Corporation, Sydney, Australia), with a 6-MHz and 15-MHz linear transducer by a single experienced ultrasonographer using a standardized protocol as previously described.8

36.2.5 Statistical Analysis

Outcomes are reported as the mean � standard error of the mean. Nonparametric data was compared using Wilcoxon signed rank tests. Parametric data was compared using Student?s t-tests.

36.3 Results

After applying initial inclusion and exclusion criteria on 2,745 patients receiving rotator cuff repairs by the senior author, 69 patients receiving synthetic patches were identified as eligible for the study?26 patients had received PTFE felt patches and 43 ePTFE patches.

36.3.1 Matching for Tear Size between Patch Groups

The intraoperatively measured tear size between the PTFE felt and ePTFE groups in mediolateral and anteroposterior planes and tear area were compared. There was a significant difference between the anteroposterior tear size (ePTFE being bigger) between the groups. To correct this, the five largest ePTFE patch patients were excluded. After these were excluded, there was no significant difference in anteroposterior tear size between the groups (p = 0.09).

36.3.2 Direct-Repair Comparison Group

The direct-repair group was created from all patients receiving suture-anchor repairs by the senior surgeon. Only operations occurring between the date of the first patch patient (May 25, 2010) and last patch patient (October 21, 2013) were considered. Patients also had to have tears with intraoperative measurements no larger than the maximum dimensions (80 mm anteroposterior, 70 mm mediolateral) and no smaller than the minimum dimensions (20 mm anteroposterior, 20 mm mediolateral) of the patch patients. 166 patients met these criteria.

36.3.3 Matching for Tear Size between Patch Groups and Direct-Repair Groups

? To ensure there was a similar preoperative tear size between the direct-repair and patch groups, a following posthoc matching procedure was performed.

? Tear size between all groups was compared using Student?s t-tests. There was a significant difference between both PTFE felt and ePTFE and direct-repair group anteroposterior tear size, with the direct-repair group being smaller. The 48 smallest anteroposterior tears were then removed from the direct-repair group and again compared to the PTFE felt and ePTFE group, leaving no significant difference between any group for anteroposterior tear size.

? There remained a significant difference between both PTFE felt and ePTFE, and the direct-repair group in terms of mediolateral tear size, with the direct-repair group being smaller. The 26 smallest mediolateral tears were removed from the direct-repair group. After these exclusions, 80 patients remained in the direct-repair group.

? To ensure 100 patients were in the direct-repair group, the restriction on operation date was expanded. Twenty additional patients with the largest mediolateral tear size were recruited in order of most recent operation going back from the date of the earliest patch-repair operation. Patients were not included if they had mediolateral tears larger than the largest mediolateral tear size in either the ePTFE or PTFE felt groups.

? Once these additional patients were included, there was a significant difference between the direct-repair and PTFE felt and ePTFE groups in anteroposterior tear size, with the direct-repair group being larger. The 11 patients with the largest anteroposterior tear were excluded and replaced with patients with the largest anteroposterior tear that did not create a significant difference between the direct-repair group and the PTFE felt and ePTFE groups. Patients were added in order of most recent operation before the earliest operation in the PTFE felt and ePTFE groups.

? This resulted in a direct-repair group of 100 patients with comparable anteroposterior, mediolateral, and total tear area to PTFE felt and ePTFE patch groups.

36.3.4 Demographics

The three groups were similar with respect to gender, age at surgery, which shoulder was affected, or how long there had been from the initial injury to surgery between any group (? Table 36.1, ? Table 36.2).

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36.3.5 Intraoperative Data

? The surgeon?s opinion of quality of tendon tissue and tendon mobility was significantly better in the direct-repair group than in the PTFE felt and ePTFE group (? Table 36.3 and ? Table 36.4).

? Operative time was longer for patch patients (PTFE felt 59 minutes � 5.0, ePTFE 49 minutes � 2.0) than for the direct-repair group (27 minutes � 1.4); however, there was no significant difference in time for the different types of patches (? Table 36.3, ? Table 36.4).

36.3.6 Patient-Ranked Outcomes

? Overall shoulder satisfaction.

? Patients in all groups had a significant improvement in shoulder function 1week postoperation that was sustained at 6 months (p > 0.001).

? Patients receiving a PTFE felt patch had a rated their shoulder satisfaction higher than patients receiving a direct repair at 1 week (p=0.035); however, there was no other significant difference between groups at any time point (? Fig. 36.1).

? Pain.

? There was no reported difference between any group in shoulder stiffness, difficulty reaching behind back, level of pain during overhead activities, frequency of extreme pain, and current level of activity at work. ePTFE patients reported less pain than the direct-repair group preoperatively (p=0.027); however, this difference was not significant at future time points.

? The direct-repair group of patients had a higher level of reported sporting activity than the ePTFE group at 6 months (p=0.02).

? Patients in the ePTFE group reported significantly more pain at rest after 6 months than the direct-repair group (p=0.031). There was no difference in level of pain during sleep between groups; the one exception was patients at 6 weeks in the ePTFE group being worse than the PTFE felt group (p=0.049).

? There was no difference reported in any group in pain during overhead activities or pain during sleep at 6 months postoperation.