Perianchor Cyst Formation Around Biocomposite Biodegradable Suture Anchors After Rotator Cuff Repair

Magnetic resonance imaging for relationship between the severity of perianchor fluid collection and rotator cuff integrity after arthroscopic double-row suture-bridge rotator cuff repair

PURPOSE

The primary purpose of this study was to assess perianchor fluid collection (PFC) severity of medial anchor and rotator cuff integrity association after arthroscopic double-row suture-bridge rotator cuff repair (RCR) and the secondary purpose was to identify the demographic and radiologic risk factors for high-grade PFC.

HYPOTHESIS

Re-tear rate would be significant higher in patients with high-grade PFC.

METHODS

We retrospectively reviewed patients with arthroscopic double-row suture-bridge RCR for full-thickness rotator cuff tear (RCT) at our institution between February 2012 and May 2018. Based on the PFC severity, they were divided into the no-fluid (no fluid collection), low-grade (minimal or local fluid collection around the anchor), and high-grade (fluid collection beyond the entire length of the anchor) groups. Magnetic resonance imaging was performed 6 months postoperatively for assessing PFC severity and repaired rotator cuff integrity association, besides evaluating correlation between severity and various demographic and radiologic factors, including work level (low/medium/high) and RCT size.

RESULTS

This study included 312 patients, 181 (58%) in the no fluid group, 82 (26.3%) in the low-grade PFC group, and 49 (15.7%) in the high-grade PFC group. Re-tear occurred in 73 (23.4%) patients and was more frequent in the high-grade group (26/49 [53.1%]) than in the no-fluid (27/181 [14.9%]; p<0.001) and low-grade (20/82 [24.4%]; p=0.001) groups, without statistically significant differences between the latter two (p=0.082). Among the demographic factors, work level (low/medium/high) differed significantly between the no-fluid (22.1%/58.0%/19.9%), low-grade (25.7%/46.3%/28.0%), and high-grade (26.5%/34.7%/38.8%) groups (p=0.026). Among the radiologic factors, the mediolateral tear size differed significantly between the three groups (no-fluid group: 1.7±0.8cm, low-grade group: 1.8±0.6cm, high-grade group: 2.2±1.0cm; p=0.003). Multivariate regression analysis showed that mediolateral tear size (odds ratio: 1.821; 95% confidence interval: 1.258-2.636; p=0.001) was an independent risk factor for high-grade PFC.

CONCLUSIONS

After arthroscopic double-row suture-bridge RCR, the highest re-tear rate was observed in patients with high-grade PFC, while there was no significant difference in rates between no-fluid and low-grade PFC groups. As PFC severity increased, the risk of re-tear increased. In particular, larger mediolateral tear size was associated with high-grade PFC.

LEVEL OF EVIDENCE

III; case-control study.

Association of Lateral Extra-Articular Tenodesis With Improved Graft Maturity on MRI 2 Years After ACL Reconstruction With Quadriceps Tendon Autograft in Skeletally Immature Athletes

Background

Quadriceps tendon autograft (QTA) has recently gained popularity in the treatment of anterior cruciate ligament (ACL) ruptures in pediatric patients. The addition of lateral extra-articular tenodesis (LET) to an ACL reconstruction (ACLR) has been found to reduce the risk of ACL retear in high-risk patients.

Purpose

To (1) compare ACL graft maturity using signal intensity ratios (SIRs) on magnetic resonance imaging (MRI) scans in skeletally immature patients undergoing ACLR with QTA either with or without concomitant LET and (2) evaluate LET safety by calculating the physeal disturbance-related reoperation rate in the ACLR+LET group.

Study Design

Cohort study; Level of evidence, 3.

Methods

The records of patients aged ≤18 years who underwent ACLR between 2015 and 2021 were reviewed retrospectively. Patients undergoing ACLR with QTA who had open distal femoral and proximal tibial physes on MRI scans and a minimum 2-year follow-up data were included. SIR values were measured on sagittal MRI scans by averaging the signal at 3 regions of interest along the ACL graft and dividing by the signal of the posterior cruciate ligament at its insertion. Statistical analysis was performed to evaluate differences in SIR values at 6 months, 1 year, and 2 years postoperatively in patients who underwent ACLR alone versus ACLR+LET.

Results

Overall, 29 patients were included in the study: 16 patients in the ACLR+LET group and 13 patients in the ACLR-only group. There were no significant differences in SIR values between groups at the 6-month or 1-year postoperative timepoints. At 2 years postoperatively, the median SIR of the ACLR+LET group was significantly lower than that of the ACLR-only group on both univariate (1.33 vs 1.86, respectively, P = .0012) and multivariate regression analyses adjusting for both sex and surgical technique (β = -0.49 [95% CI, -0.91 to -0.05]; P = .029). There were no cases of reoperation for physeal disturbance in patients who underwent ACLR+LET.

Conclusion

The addition of LET to an ACLR with QTA was associated with lower average SIR values and thus improved graft maturity at 2 years postoperatively compared with ACLR alone in skeletally immature patients. The addition of LET to an ACLR was found to be safe in skeletally immature patients.

Arthroscopic transosseous anchorless rotator cuff repair reduces bone defects related to peri-implant cyst formation: a comparison with conventional suture anchors using propensity score matching

BACKGROUND

The transosseous anchorless repair (ToR) technique was recently introduced to avoid suture anchor-related problems. While favorable outcomes of the ToR technique have been reported, no previous studies on peri-implant cyst formation with the ToR technique exist. Therefore, this study compared the clinical outcomes and prevalence of peri-implant cyst formation between the ToR technique and the conventional transosseous equivalent technique using suture anchors (SA).

METHODS

Cases with arthroscopic rotator cuff repair (ARCR) between 2016 and 2018 treated with the double-row suture bridge technique were retrospectively reviewed. Patients were divided into ToR and SA groups. To compare clinical outcomes, 19 ToR and 57 SA cases without intraoperative implant failure were selected using propensity score matching (PSM). While intraoperative implant failure rate was analyzed before PSM, retear rate, peri-implant cyst formation rate, and functional outcomes were compared after PSM.

RESULTS

The intraoperative implant failure rate (ToR, 8% vs. SA, 15.3%) and retear rate (ToR, 5.3% vs. SA, 19.3%) did not differ between the two groups (all P>0.05). However, peri-implant cysts were not observed in the ToR group, while they were observed in 16.7% of the SA group (P=0.008). Postoperative functional outcomes were not significantly different between the two groups (all P>0.05).

CONCLUSIONS

The ToR technique produced comparable clinical outcomes to conventional techniques. Considering the prospect of potential additional surgeries, the absence of peri-implant cyst formation might be an advantage of ToR. Furthermore, ToR might reduce the medical costs related to suture anchors and, thereby, could be a useful option for ARCR. Level of evidence: III.

Degradation behavior of ZE21C magnesium alloy suture anchors and their effect on ligament-bone junction repair

Current materials comprising suture anchors used to reconstruct ligament-bone junctions still have limitation in biocompatibility, degradability or mechanical properties. Magnesium alloys are potential bone implant materials, and Mg²⁺ has been shown to promote ligament-bone healing. Here, we used Mg-2 wt.% Zn-0.5 wt.% Y-1 wt.% Nd-0.5 wt.% Zr (ZE21C) alloy and Ti6Al4V (TC4) alloy to prepare suture anchors to reconstruct the patellar ligament-tibia in SD rats. We studied the degradation behavior of the ZE21C suture anchor via in vitro and in vivo experiments and assessed its reparative effect on the ligament-bone junction. In vitro, the ZE21C suture anchor degraded gradually, and calcium and phosphorus products accumulated on its surface during degradation. In vivo, the ZE21C suture anchor could maintain its mechanical integrity within 12 weeks of implantation in rats. The tail of the ZE21C suture anchor in high stress concentration degraded rapidly during the early implantation stage (0-4weeks), while bone healing accelerated the degradation of the anchor head in the late implantation stage (4-12weeks). Radiological, histological, and biomechanical assays indicated that the ZE21C suture anchor promoted bone healing above the suture anchor and fibrocartilaginous interface regeneration in the ligament-bone junction, leading to better biomechanical strength than the TC4 group. Hence, this study provides a basis for further research on the clinical application of degradable magnesium alloy suture anchors.

Soft Anchors for Rotator Cuff Repair: A Review

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All-suture anchors or so-called "soft" anchors, initially adapted for labral repairs, have increased in popularity for use in rotator cuff repair because of their smaller size, decreased occupation of the footprint, improved points of fixation, ease of use, and ease of revision.

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In limited series, soft anchors have demonstrated equivalent biomechanical and clinical performance compared with hard body anchors for rotator cuff repair.

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Perianchor cyst formation can occur with both hard body and soft anchors.

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Biomechanical and clinical data support aiming for vertical angles of insertion for soft anchors.

Evaluation of Radiographic Changes 5 Years After Arthroscopic Rotator Cuff Repair

Background:

Radiographic changes in the glenohumeral joint often occur after rotator cuff repair; however, the details of the progression and underlying causes remain unknown.

Purpose:

To retrospectively evaluate the timing and frequency of radiographic changes after arthroscopic rotator cuff repair and to clarify the predictive factors that affect the onset of such changes using multivariate analysis.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We retrospectively reviewed 100 patients with 5 years of follow-up after arthroscopic rotator cuff repair and evaluated the postoperative shift in radiographic findings on plain radiographs every year during follow-up. Factors related to osteoarthritis, acromial spur re-formation, and greater tuberosity resorption at 5 years after surgery were evaluated using logistic regression analyses. Explanatory variables included preoperative factors, intraoperative factors, and postoperative retear. Baseline variables significant in the univariate analyses were included in the multivariate models.

Results:

Of the 100 patients, 12 developed osteoarthritis, 26 developed acromial spur formation, and 16 developed greater tuberosity resorption at 5 years after surgery. The incidence and grade of osteoarthritis and acromial spur gradually increased over time postoperatively. On the other hand, greater tuberosity resorption developed within 2 years after surgery but did not progress later. Multivariate analysis showed that a larger anteroposterior tear size (odds ratio [OR], 1.09; 95% CI, 1.01-1.17; P = .037) was a risk factor for postoperative osteoarthritis. Early retear (OR, 10.26; 95% CI, 1.03-102.40; P = .047) was a risk factor for acromial spur re-formation. Roughness of the greater tuberosity (OR, 9.07; 95% CI, 1.13-72.82; P = .038) and larger number of suture anchors (OR, 3.34; 95% CI, 1.66-6.74; P = .001) were risk factors for greater tuberosity resorption.

Conclusion:

Our study showed that radiographic changes occurred in 40% of patients within 5 years after arthroscopic rotator cuff repair. While the osteoarthritic changes and acromial spur re-formation gradually progressed postoperatively, the greater tuberosity resorption stopped within 2 years after surgery. Tear size, morphology of the greater tuberosity, and the number of suture anchors can affect radiographic changes. Furthermore, this study suggested that acromial spur re-formation may be an indicator of early retears.

Perianchor cyst formation in all-suture anchor after rotator cuff repair: an evaluation of anchor insertion angle

BACKGROUND

Previous studies reported that micromotion after all-suture anchor implantation can lead to perianchor cyst formation (PCF), leading to risk of retear. Modifying anchor insertion angle (AIA) is known to be one of the various ways to increase anchor stability. However, there currently are few studies that assess the correlation between PCF, AIA, and retear.

PURPOSE

To find the correlation of PCF and the repaired rotator cuff integrity with AIA after arthroscopic double-row suture-bridge rotator cuff repair (RCR) using an all-suture anchor in the medial row.

METHODS

A total of 218 patients who underwent arthroscopic double-row suture-bridge RCR were retrospectively reviewed. All patients underwent RCR using all-suture anchors and polyether ketone anchors in the medial and lateral rows, respectively. Magnetic resonance imaging was conducted 6 months after the surgery to evaluate PCF, AIA, and integrity of the repaired cuff. The all-suture anchor insertion angle in the medial row was measured with reference to the greater tuberosity to assess the relationship between the AIA and PCF. The correlations between PCF, AIA, and post-RCR integrity were evaluated including various demographic and radiologic factors.

RESULTS

Perianchor cysts were formed in 93 patients (42.7%). Mediolateral tear size (2.1 ± 1.2 cm vs. 1.7 ± 0.9 cm, P = .034) and AIA (61.9° ± 15.2° vs. 68.4° ± 13.0°, P = .001) were significantly different between patient groups with and without perianchor cysts. Multivariate logistic regression analysis showed that mediolateral tear size (odds ratio [OR] 1.318, 95% confidence interval [CI] 1.008-1.724; P = .043) and AIA (OR 0.967, 95% CI 0.947-0.988; P = .002) were independent risk factors for PCF. In addition, PCF was observed more frequently (69.6% vs. 32.1%, P < .001) and the AIA was lower (59.4° ± 13.7° vs. 67.8° ± 13.8°, P < .001) in the retear group than in the healed group.

CONCLUSIONS

Perianchor cysts were formed in approximately 40% of patients who underwent arthroscopic double-row suture-bridge RCR using all-suture anchors. Low AIA and large mediolateral tear size were risk factors for PCF. Moreover, perianchor cyst and AIA were correlated with post-RCR integrity. Therefore, a high AIA must be carefully considered when all-suture anchors are inserted into the medial row when performing RCR.

Perianchor Cyst Formation Is Similar Between All-Suture and Conventional Suture Anchors Used for Arthroscopic Rotator Cuff Repair in the Same Shoulder

Purpose

The purpose of this study was to compare perianchor cyst formation between soft and hard suture anchors placed in the same patient 1 year after arthroscopic rotator cuff repair (ARCR).

Methods

This study reviewed patients who underwent primary ARCR using a “hybrid” technique using at least one soft anchor (FiberTak, Arthrex, Naples, FL) and one hard anchor (SwiveLock) placed in the same shoulder between January 1, 2018 and December 31, 2018. Magnetic resonance imaging was obtained at minimum 1-year postoperative to assess cyst formation (perianchor fluid signal) and rotator cuff healing. Range of motion (ROM) and patient-reported outcome measures (PROMs) were evaluated at baseline and 1-year follow up. PROMs included visual analog scale pain score, Simple Shoulder Test score, American Shoulder and Elbow Surgeon (ASES) score.

Results

Nineteen patients with a combined 45 hard and 26 soft suture anchors were available for follow-up at a mean of 20 months postoperatively. There was a higher proportion of grade 1 fluid signal changes in the hard anchor group compared to the soft group (62.2% to 7.7; P < .001); however, there was no difference in the incidence of cyst formation (grade 2 or 3 changes) between groups (13.3% vs 3.8%; P = .251). There was also no difference in the rate of cyst formation between biocomposite and polyether-ether-ketone-type hard anchors (18.2% vs 0%; P = .113) or between anchors placed at the greater and lesser tuberosities (10.2% vs 5.3%, P = .519).

Conclusion

Hard suture anchors showed increased fluid signal compared to soft suture anchors at short-term follow-up after ARCR, but there was no difference in cyst formation between anchor types.

Biomechanical properties of a suture anchor system from human allogenic mineralized cortical bone matrix for rotator cuff repair

Background

Suture anchors (SAs) made of human allogenic mineralized cortical bone matrix are among the newest developments in orthopaedic and trauma surgery. Biomechanical properties of an allogenic mineralized suture anchor (AMSA) are not investigated until now. The primary objective was the biomechanical investigation of AMSA and comparing it to a metallic suture anchor (MSA) and a bioabsorbable suture anchor (BSA) placed at the greater tuberosity of the humeral head of cadaver humeri. Additionally, we assessed the biomechanical properties of the SAs with bone microarchitecture parameters.

Methods

First, bone microarchitecture of 12 fresh frozen human cadaver humeri from six donors was analyzed by high-resolution peripheral quantitative computed tomography. In total, 18 AMSAs, 9 MSAs, and 9 BSAs were implanted at a 60° angle. All three SA systems were systematically implanted alternating in three positions within the greater tuberosity (position 1: anterior, position 2: central, position 3: posterior) with a distance of 15 mm to each other. Biomechanical load to failure was measured in a uniaxial direction at 135°.

Results

Mean age of all specimens was 53.6 ± 9.1 years. For all bone microarchitecture measurements, linear regression slope estimates were negative which implies decreasing values with increasing age of specimens. Positioning of all three SA systems at the greater tuberosity was equally distributed (p = 0.827). Mean load to failure rates were higher for AMSA compared to MSA and BSA without reaching statistical significance between the groups (p = 0.427). Anchor displacement was comparable for all three SA systems, while there were significant differences regarding failure mode between all three SA systems (p < 0.001). Maximum load to failure was reached in all cases for AMSA, in 44.4% for MSA, and in 55.6% for BSA. Suture tear was observed in 55.6% for MSA and in 22.2% for BSA. Anchor breakage was solely seen for BSA (22.2%). No correlations were observed between bone microarchitecture parameters and load to failure rates of all three suture anchor systems.

Conclusions

The AMSA showed promising biomechanical properties for initial fixation strength for RCR. Since reduced BMD is an important issue for patients with chronic rotator cuff lesions, the AMSA is an interesting alternative to MSA and BSA. Also, the AMSA could improve healing of the enthesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05371-0.

Periimplant osteolysis does not affect the outcome of rotator cuff repair: a systematic review and meta-analysis

PURPOSE

The goal of this study was to perform a systematic review and meta-analysis to compare the clinical and radiologic outcomes of rotator cuff repair, depending on the presence of developed periimplant osteolysis (PIO) after using suture anchors.

METHODS

The electronic databases of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for articles published up until October 2019 to find relevant articles comparing the outcomes of rotator cuff repair between the periimplant osteolysis group and non-periimplant osteolysis group. Data searching, extraction, analysis, and quality assessment were performed according to the Cochrane Collaboration guidelines. The results are presented as risk ratio (RR) for binary outcomes and standardised mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI).

RESULTS

Six clinical studies were included. No significant differences were found between the group with periimplant osteolysis and the group without periimplant osteolysis regarding retear rate (RR = 1.34; 95% CI 0.93-1.94; I² = 28%), postoperative clinical scores (SMD = 0.29; 95% CI - 0.26 to 0.83; I² = 80%) and range of motion (ROM); forward flexion (SMD = 0.39; 95% CI - 0.16 to 0.93; I² = 0%), external rotation (SMD = - 0.10; 95% CI - 0.64 to 0.45; I² = 0%) and internal rotation (SMD = - 0.37; 95% CI - 0.92 to 0.17; I² = 0%).

CONCLUSION

The presence of periimplant osteolysis after rotator cuff repair with suture anchor does not affect the clinical outcomes such as retear rate, clinical scoring, and ROM. However, as there was no standard consensus on the criteria for evaluating periimplant osteolysis, this result may not fully reflect the effect of periimplant osteolysis depending on its severity.

LEVEL OF EVIDENCE

Level IV.

Clinical and Radiological Outcomes of Rotator Cuff Repairs Using All-Suture Anchors as Medial Row Anchors

Background

The aim of our study is to report the clinical and radiological outcomes of a series of prospectively enrolled patients who have had double-row transosseous equivalent rotator cuff repairs, where all-suture anchors were used as medial-row anchors, with a minimum follow-up of 1 year.

Methods

Twenty-two consecutive patients underwent arthroscopic transosseous equivalent double-row rotator cuff repair using all-suture anchors as medial-row anchors. Oxford Shoulder Score, Constant Score and Visual Analogue Scale pain score, together with shoulder range of motion, were used preoperatively and at 3 months, 6 months and final follow-up. Radiological evaluation was performed with magnetic resonance imaging at one-year post surgery to assess the structural integrity of the repair and the rate of cyst formation in greater tuberosity.

Results

The patient mean age was 61 years (range 46-75). Minimum follow-up was 1 year, and the mean final follow-up was 15 months (range 12-24). Healing failure in our patients was less than 5% (1/22 patients). There were significant improvements in shoulder function outcome scores at final follow-up. The Constant and Oxford scores were 78 and 44 at final follow-up respectively. There were similar magnitudes of improvement in range of motion (combined abduction and rotation), pain score and supraspinatus strength at final follow up. The improvements in outcome scores were already statistically significant at 3 months (P<.001). Using Kim's classification for cyst formation on T2-weighted MRI images, we observed no fluid or minimal fluid collection in 85% of the patients (17/22 patients). There were no correlations between the grade of bone changes and the clinical outcomes.

Conclusion

It is safe to use all-suture anchors as medial-row anchors when performing double-row anchor transosseous equivalent rotator cuff repairs. The purported advantages of all-suture anchors may outweigh their perceived disadvantages in rotator cuff repair surgery.

Long-term follow-up of perianchor cyst formation after rotator cuff repair

Background

Perianchor cyst formation (PCF) can occur after arthroscopic rotator cuff repair with poly-L-lactic acid (PLLA) anchors; however, little is known about PCF after all-suture anchor (ASA) use.

Methods

We reviewed patients who underwent double-row arthroscopic rotator cuff repair from 2012 to 2017 with ASAs implanted in the medial row and PLLA anchors in the lateral row. We evaluated PCF (graded on magnetic resonance imaging) and compared physical examination and functional surveys between patients with PCF (WC) and without PCF (WoC) at long-term follow-up.

Results

Among twenty-two patients (23 shoulders), 93% of PLLA anchors (vs. 79% ASA) displayed a grade 0 PCF, P = .100. No PLLA anchors had a grade 3 or 4 PCF, compared to 11% of ASAs, P = .158. At a mean postoperative follow-up time of 113 weeks, there was no significant difference between WC and WoC cohorts with regard to range of motion, rotator cuff strength, American Shoulder and Elbow Surgeons survey scores, or retear rates. However, the WoC cohort had a significantly higher University of California at Los Angeles shoulder survey score at final follow-up (34.3 WoC vs. 30.9 WC, P = .024).

Conclusion

No difference was found in PCF between ASAs and PLLA anchors. At long-term follow-up, WoC patients had significantly improved functional outcome scores, based on the University of California at Los Angeles survey, but equivalent range of motion and rotator cuff strength examinations compared with WC patients.

Arthroscopic remplissage with all-suture anchors causes cystic lesions in the humerus: a volumetric CT study of 55 anchors

PURPOSE

To evaluate with computed tomography (CT) the incidence of implant-related osteolysis after implantation of two types of all-suture anchors during remplissage for the management of Hill-Sachs lesions in shoulder instability.

METHODS

Single-cohort, observational study with a minimum of 12 months follow-up. Twenty-five participants (19 males and 6 females; mean age 37.4 years [SD: 11.6]) with Hill-Sachs lesions requiring remplissage were evaluated with a CT performed a mean of 14.1 [3.74] months after surgery. Fifty-five all-suture anchors (19 2.3 mm Iconix and 36 1.7 mm Suturefix) were used. The volume of the bone defects was measured in the CT. Every anchor was classified into one of four groups: (1) no bone defect. (2) Partial bone defect (bone defects smaller than the drill used for anchor placement). (3) Tunnel enlargement (bone defect larger than the drill volume but smaller than twice that volume). (4) Cystic lesion (bone defect larger twice the drill volume).

RESULTS

No bone defect was identified in only two anchors (3.6%, 95% CI 0.4-12.5%). A partial bone defect was found in eight anchors (14.5%, 95% CI 6.5-26.7%). In 35 anchors (63.6%, 95% CI 49.6-76.2%), there was enlargement of the bone defect that was smaller than 200% the size of the drill used. Ten anchors caused bone defects larger than twice the size of the drill used (18.2%, 95% CI 9.1-30.9%). The defect size was a mean of 89 mm³ (SD: 49 mm³, minimum 0 mm³, maximum 230 mm³).

CONCLUSION

When using all-suture anchors in arthroscopic remplissage during instability surgery, relevant bone osteolytic defects are common at 1-year-follow-up. Cystic defects larger than twice the volume of the resected bone during implantation develop in one in six anchors and significant tunnel widening will develop in another three out of five anchors. This bone loss effectively increases the size and depth of the Hill-Sachs lesions but does not seem to affect short-term clinical outcomes.

LEVEL OF EVIDENCE

Level IV.

Regenesorb and polylactic acid hydroxyapatite anchors are associated with similar osseous integration and rotator cuff healing at 2 years

BACKGROUND

Commercially available suture anchors for rotator cuff repairs can differ significantly in architecture and material. Clinical data on their osseous integration and its effect on patient-reported outcomes is scarce. Preclinical investigations indicated a higher rate of osseous integration for the open-architecture design of the Healicoil Regenesorb anchor than the closed-threaded design of the Twinfix (Smith & Nephew). The purpose of this study was to investigate these 2 anchors with different architecture and material to determine their effect on osseous integration and clinical outcomes after rotator cuff repair.

METHODS

A prospective randomized controlled trial was performed from 2014 to 2019. Sixty-four patients (39 females, 25 males) with an average age of 58.7 years who underwent arthroscopic rotator cuff repair by one of 4 board-certified, fellowship-trained surgeons were randomized to receive Healicoil Regenesorb (PLGA/ß-TCP/Calcium Sulfate) or Twinfix Ultra HA (PLLA/HA) anchors. Thirty-two patients had Healicoil anchors implanted, and 32 patients had Twinfix anchors implanted. Of the 64 patients, 51 returned at 24 months for computed tomographic (CT) examination (25 Twinfix and 26 Healicoil) to determine osteointegration of the anchors. Patient-reported outcomes, including Penn Shoulder Score (PENN), Western Ontario Rotator Cuff Index, visual analog scale, EQ-5D, Single Assessment Numeric Evaluation, Global Rating of Change, were collected at baseline, 6 weeks, 3 months, 6 months, 12 months, and 24 months. Ultrasonography was used to assess rotator cuff integrity after 6 months. Two board-certified, fellowship-trained orthopedic surgeons, blinded to the type of anchors, analyzed the CT scans to assess the anchor osteointegration at 24 months using a previously published grading scale.

RESULTS

There were no differences in demographics, preoperative outcomes, or baseline characteristics such as tear size, number of anchors, Goutallier classification, or smoking status between groups. There was no difference in osseous integration between the 2 anchors at 24 months (P = .117). Eight patients had rotator cuff retears, of which 2 patients had Twinfix anchors and 6 patients had Healicoil anchors (P = .18). There were no statistically significant differences in patient-reported outcomes or complications between groups. The 2-year PENN scores were 89 with the Twinfix and 88 with Healicoil anchors (P = .55).

CONCLUSION

Despite differences in material and anchor architecture, the rate of healing and patient-reported outcomes were similar between the Twinfix and Healicoil anchor groups. The rate of osteointegration was the same at 2 years.

Postoperative bone marrow edema lasts no more than 6 months after uncomplicated arthroscopic double-row rotator cuff repair with PEEK anchors

PURPOSE

To assess the natural evolution of the osseous reaction following arthroscopic double-row rotator cuff repair with PEEK anchors and to analyze its correlation with clinical shoulder function.

METHODS

Between 2015 and 2017, 159 patients received arthroscopic double-row rotator cuff repair with PEEK anchors and underwent serial clinical and radiological follow-up (3, 6, 12, and 24 months). Radiological results were analyzed by tendon integrity, bone marrow edema, and peri-implant osteolysis. Clinical shoulder function was evaluated with the Constant score.

RESULTS

One-hundred and seventeen patients were enrolled; among them, 63% demonstrated bone marrow edema around the anchors on postoperative 3-month MRI. The edema area percentage was 41% ± 7%. At 6 months, edema was only seen in 12% of cases, with an area percentage of 18% ± 5%. At 12 and 24 months, edema was rarely present. Fluid signals around the anchor were observed in 17.6%, 42.7%, 33.3%, and 21.0% of patients at 3, 6, 12, and 24 months, respectively; the tunnel widening values were 1.1 ± 0.4 mm, 1.8 ± 0.5 mm, 2.3 ± 0.6 mm, and 2.2 ± 0.7 mm at each follow-up, respectively. The sign of osteolysis was significantly more obvious around the lateral anchor than around the medial anchor. The presence of an osseous reaction was not correlated with worse clinical outcome.

CONCLUSION

Osseous reactions following arthroscopic rotator cuff repair are common and significant even with PEEK anchors. Bone marrow edema does not last more than 6 months in patients without complications. Peri-implant osteolysis is more evident around the lateral anchor than around the medial anchor and improves gradually over time. The sign of osteolysis is not correlated with clinical shoulder function. Based on these findings, surgeons should be cautious about bone marrow edema lasting more than 6 months following arthroscopic rotator cuff repair.

LEVEL OF EVIDENCE

Level IV.

Novel and reproducible technique coping with intraoperative anchor pullout during arthroscopic rotator cuff repair

PURPOSE

To evaluate the incidence of intraoperative anchor pullout during arthroscopic rotator cuff repair, to compare the outcomes of different methods of managing anchor pullout, and to introduce a new technique for anchor pullout.

METHODS

1076 patients who underwent arthroscopic rotator cuff repair using a single-row repair technique were included. In 483 patients, rotator cuff repair was performed using a screw-in type anchor, and in 593 patients, soft anchors were used. When intraoperative anchor pullout occurred, it was managed by buddy screwing, anchor insertion in a different location, cement augmentation, or by bar anchoring using a threaded Steinmann pin. Plain radiography and sonography were used to check anchor locations and healing.

RESULTS

Fifty-two patients experienced anchor pullout intra- or postoperatively (48 and four patients, respectively). Anchor pullouts were more frequently observed for larger tears, women, older patients, and in patients with preoperative stiffness (limitations of both active and passive movements of the affected shoulder joint). For screw-in type anchors, pullout during surgery occurred in 16 patients (3.3%, 16/483), and all were managed using the buddy screwing technique. For soft anchor cases, pullout occurred in 32 patients (5.4%, 32/593) and was managed by anchor insertion in a different location (17 patients), cement augmentation (two patients), or bar anchoring using a threaded Steinmann pin (13 patients). Three patients managed by buddy screwing and two patients managed by anchor insertion in a different location had anchor failure after repair. Tendon healing at 6 months was observed in 12/16 patients treated by buddy screwing, 11/17 treated by anchor insertion in a different location, 2/2 treated by cement augmentation, and 12/13 treated by bar anchoring with a threaded Steinmann pin.

CONCLUSION

Intraoperative anchor pullout during arthroscopic rotator cuff repair is an uncommon but cumbersome complication. There are some techniques already introduced to deal with this complication. In comparison, not one technique is overwhelmingly superior to others; however, our new technique which is bar anchoring with a threaded Steinmann pin could be another solution, since it could utilize primary anchor sites and results appear to be acceptable. Level of evidence III.

Serial Changes in Perianchor Cysts Following Arthroscopic Labral Repair Using All-Suture Anchors

Backgroud

Changes in perianchor cysts around the all-suture anchors, which demonstrate distinguished features from the biocomposite anchors, have not been revealed sufficiently. The purpose of this study was to investigate serial changes of perianchor cysts according to the location of the inserted anchor in the glenoid in arthroscopic labral repair using all-suture anchors.

Methods

We enrolled 43 patients who underwent computed tomography (CT) immediately postoperatively and CT arthrogram (CTA) at 1 year or 2 years after arthroscopic labral repair using a 1.3-mm all-suture anchor for recurrent anterior shoulder dislocation with or without a superior labral tear from anterior to posterior and a posterior labral tear. The mean diameter and tissue density (HU) of perianchor cysts were measured depending on the location in the glenoid. Clinical outcomes, labral healing, and redislocation rate were evaluated at 2 years after surgery.

Results

On functional assessment, the mean American Shoulder and Elbow Surgeons score and Rowe score improved statistically significantly after surgery (from 47.9 ± 14.3 preoperatively to 90.1 ± 9.6 postoperatively and from 45.3 ± 12.4 preoperatively to 92.2 ± 10.1 postoperatively, respectively; p < 0.01). Postoperative redislocations were found in 2 patients (4.7%). In radiological evaluation, the mean diameter of perianchor cysts at postoperative 1 year (3.24 ± 0.65 mm) was significantly larger than the immediate postoperative diameter; however, there was no significant difference between postoperative 1 year and 2 years (3.23 ± 0.57 mm). Tissue density at the center of cysts demonstrated no significant difference between 1 and 2 year postoperatively (107.7 ± 29.8 HU [superior], 99.7 ± 31.7 HU [anteroinferior], and 105.1 ± 25.0 HU [posterior] vs. 109.1 ± 26.1 HU [superior], 106.4 ± 30.3 HU [anteroinferior], and 111.0 ± 32.9 HU [posterior]). The mean diameter of perianchor cysts in the anteroinferior position was largest compared with that in superior or posterior positions.

Conclusions

Perianchor cysts associated with all-suture anchors enlarged significantly within 1 year after arthroscopic labral repair regardless of the insertion location in the glenoid. However, the size and tissue density of perianchor cysts were similar at postoperative 1 and 2 years, and satisfactory stability and clinical outcomes were obtained.

Effects of a Thermosensitive Antiadhesive Agent on Single-Row Arthroscopic Rotator Cuff Repair

BACKGROUND

Postoperative stiffness after rotator cuff repair is a common complication that can lead to poor outcomes and patient discomfort. The application of an antiadhesive agent at the time of repair recently became an option for clinicians, but little information is available on its effects.

PURPOSE

To evaluate and compare retear rates, the incidence of postoperative stiffness, and the clinical outcomes of patients who underwent cuff repair with or without the application of an antiadhesive agent.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Among 296 patients who underwent arthroscopic rotator cuff repair surgery, we compared the outcomes of those injected with a thermosensitive gel antiadhesive agent into the subacromial space (112 cases) versus noninjected controls (184 cases). Retear rates in the 2 groups were determined by magnetic resonance imaging at 1 year after surgery. Shoulder joint range of motion and functional scores were evaluated serially.

RESULTS

The rate of retear was significantly lower in the injection group (20/112 cases; 17.9%) than the control group (53/184 cases; 28.8%) (P = .034). Postoperative stiffness was not significantly different between the 2 groups (P = .710). Among the data regarding range of motion, only forward flexion at 6 months after surgery showed superior results in the injection group. Functional scores showed conflicting results: The control group had better visual analog scale scores for pain (injection vs control: 2.17 vs 1.68 at 6 months; 1.82 vs 1.28 at 12 months), American Shoulder and Elbow Surgeons scores (79.89 vs 89.64 at 12 months), and simple shoulder test scores (8.70 vs 10.06 at 12 months), whereas the injection group had better Constant-Murley scores (injection vs control: 59.49 vs 55.60 at 3 months; 77.35 vs 71.98 at 6 months; 87.28 vs 81.56 at 12 months).

CONCLUSION

The tendon healing rate was significantly higher in the group receiving an antiadhesive agent than in the control group. No intergroup difference was seen in the occurrence of postoperative stiffness. However, the pain-related functional score showed inferior results in the injection group at 12 months. The biological action of antiadhesive agents in rotator cuff repair should be further evaluated.

Clinical and Radiologic Outcomes of Combined Use of Biocomposite and PEEK Suture Anchors during Arthroscopic Rotator Cuff Repair: A Prospective Observational Study

The aim of the current study was to evaluate the functional and radiologic outcomes of biocompatible non-absorbable PEEK (polyetheretherketone) and biocomposite (poly-L-lactic acid/poly(lactic-co-glycolic acid) 70% + β-tricalcium phosphate) anchors, especially in terms of perianchor cyst formation during the first six months postoperatively. We prospectively analysed 29 patients who underwent arthroscopic rotator cuff repair between March and May 2019. Both PEEK and biocomposite suture anchors were used as lateral anchors in one body. Clinical outcomes were assessed using the shoulder range of motion (ROM), visual analogue scale (VAS) for pain and satisfactory score, American Shoulder and Elbow Surgeons (ASES) score, and Simple Shoulder Test (SST). All these were obtained in patients preoperatively at 3 and 6 months after surgery. The imaging evaluation included perianchor cyst formation, anchor absorption, repaired cuff integrity, and retear pattern. All functional outcomes significantly improved over time. The biocomposite anchor had a statistically significant tendency to form higher grades of fluid collection at 3 months after surgery. However, the perianchor cyst reduced by the sixth postoperative month. Six months postoperatively, the functional outcomes were improved after rotator cuff repair and similar degrees of perianchor cyst formation were observed, regardless of the suture anchor material used.

Biomechanical Comparison of Knotless All-Suture Anchors and Knotted All-Suture Anchors in Type II SLAP Lesions: A Cadaveric Study

PURPOSE

To compare the biomechanical performance of knotless versus knotted all-suture anchors for the repair of type II SLAP lesions with a simulated peel-back mechanism.

METHODS

Twenty paired cadaveric shoulders were used. A standardized type II SLAP repair was performed using knotless (group A) or knotted (group B) all-suture anchors. The long head of the biceps (LHB) tendon was loaded in a posterior direction to simulate the peel-back mechanism. Cyclic loading was performed followed by load-to-failure testing. Stiffness, load at 1 and 2 mm of displacement, load to repair failure, load to ultimate failure, and failure modes were assessed.

RESULTS

The mean load to repair failure was similar in groups A (179.99 ± 58.42 N) and B (167.83 ± 44.27 N, P = .530). The mean load to ultimate failure was 230 ± 95.93 N in group A and 229.48 ± 78.45 N in group B and did not differ significantly (P = .958). Stiffness (P = .980), as well as load at 1 mm (P = .721) and 2 mm (P = .849) of displacement, did not differ significantly between groups. In 16 of the 20 specimens (7 in group A and 9 in group B), ultimate failure occurred at the proximal LHB tendon. Failed occurred through slippage of the labrum in 1 specimen in each group and through anchor pullout in 2 specimens in group A.

CONCLUSIONS

Knotless and knotted all-suture anchors displayed high initial fixation strength with no significant differences between groups in type II SLAP lesions. Ultimate failure occurred predominantly as tears of the proximal LHB tendon.

CLINICAL RELEVANCE

All-suture anchors have a smaller diameter than solid anchors, can be inserted through curved guides, preserve bone stock, and facilitate postoperative imaging. There is a paucity of literature investigating the biomechanical capacities of knotless versus knotted all-suture anchors in type II SLAP repair.

Large Drill Holes Are Still Present in the Long Term After Arthroscopic Bankart Repair With Absorbable Tacks: An 18-Year Randomized Prospective Study

BACKGROUND

Studies have demonstrated the development of an osseous reaction at the drill sites of anchors after arthroscopic shoulder surgery.

PURPOSE

To investigate the drill-hole size at 18 years after arthroscopic Bankart repair using either fast polygluconate acid (PGA) or slow polylevolactic acid (PLLA) absorbable tacks and to compare the functional outcomes and development of osteoarthritis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

40 patients with unidirectional anterior shoulder instability, treated with arthroscopic Bankart repair, were randomized into the PGA group (n = 20) or the PLLA group (n = 20). Plain radiographs of both shoulders, as well as computed tomography (CT) images of the operated shoulder, were used to evaluate the drill-hole size, volume, and degenerative changes. Functional outcomes were assessed by use of the Rowe score, Constant score, and Western Ontario Shoulder Instability (WOSI) index.

RESULTS

Of the 40 patients, 32 patients returned for the follow-up (15 PGA and 17 PLLA). No significant differences were found in the population characteristics between the study groups. The mean follow-up time was 18 years for both groups. No significant differences were seen in range of motion, strength in abduction, or Constant, Rowe, and WOSI scores between the groups. Recurrence rate was 33% in the PGA group and 6% in the PLLA group during the follow-up period (P = .07). The drill-hole appearance on plain radiographs (invisible/hardly visible/visible/cystic) was 11/2/2/0 and 6/5/5/1 for the PGA and PLLA groups, respectively (P = .036). The mean ± SD drill-hole volume as estimated on CT images was 89 ± 94 and 184 ± 158 mm³ in the PGA and PLLA groups, respectively (P = .051). Degenerative changes (normal/minor/moderate/severe) on plain radiographs were 7/4/4/0 and 3/8/5/1 for the PGA and PLLA groups, respectively (P = .21), and on CT images were 5/7/3/0 and 2/6/6/3 for the PGA and PLLA groups, respectively (P = .030).

CONCLUSION

This long-term follow-up study demonstrated that the PLLA group had significantly more visible drill holes than the PGA group on plain radiographs. However, this difference was not evident on CT imaging, with both groups having several visible cystic drill holes and a substantial drill-hole volume defect. No significant differences were found between the study groups in terms of clinical outcomes.

Reliability of open architecture anchors in biocomposite material: medium term clinical and MRI evaluation. Our experience

OBJECTIVES

Comparing radiologic bone ingrowth and the clinical outcomes of an open-construct (PEEK) (polyether ether ketone) suture anchor with those of a bio-composite suture anchor (glycolic polylactic acid anchors, beta-tricalcium phosphate and calcium sulphate) in patients with arthroscopic rotator cuff repair.

METHODS

From August 2017 to January 2019, 33 patients of both sexes, aged between 44 and 78 years underwent arthroscopic rotator cuff repair for tears considered repairable with an extension not exceeding4 cm. The bioabsorbable anchors used comprised glycolic polylactic acid/beta-tricalcium phosphate/ calcium sulphate, and the non-absorbable anchors in polyetheretherketone (PEEK). All patients underwent MRI evaluation at 12 months postoperatively to determine complications and identify any re-tear.

RESULTS

Clinical scores showed an improvement from both clinical and functional point of view. There were no statistically significant changes compared to the physical examination. On radiographs, mobilizations, anchor pull-outs or other complications did not occur in each group.

CONCLUSIONS

Shoulder function improved after complete repair of the rotator cuff and similar clinical results were achieved regardless of the material and shape of the suture anchor. The bioabsorbable anchors in innovative open architecture material seem to have results comparable to peek anchors. Unfortunately, further studies are needed to define the advantages in using one material compared to the other. (www.actabiomedica.it).

A Comparison of Open-Construct PEEK Suture Anchor and Non-Vented Biocomposite Suture Anchor in Arthroscopic Rotator Cuff Repair: A Prospective Randomized Clinical Trial

PURPOSE

To compare radiologic bone ingrowth and the clinical outcomes of an open-construct (PEEK) (polyether ether ketone) suture anchor with those of a non-vented biocomposite suture anchor in patients with arthroscopic rotator cuff repair.

METHODS

Sixty-nine patients were randomly allocated into 2 groups based on type of suture anchors used for rotator cuff repair; group 1: open-construct PEEK anchor (36 patients), group 2: non-vented biocomposite anchor (33 patients). The status of bone ingrowth into the anchor and the presence of cyst formation were evaluated at 6 months postoperatively by computed tomography scan using the Modified Barber's ossification scale. The American Shoulder and Elbow Surgeons score, Constant score, and visual analog scale score for pain and range of motion were evaluated. Magnetic resonance imaging or ultrasonography was performed at 12 months postoperatively to examine the integrity of the repaired rotator cuff tendon.

RESULTS

Significant improvements in shoulder function and pain relief were observed regardless of the anchor used (both Group 1 and 2; P < .001). No differences were found in functional scores and range of motion between the 2 groups. Group 1 showed better bone ingrowth grades than group 2 (poor 2.8 vs 24.2%, fair 27.8 vs 39.4%, good 38.9 vs 33.3%, and excellent 30.6 vs 3.0%; P < .001). The rate of cyst formation around the anchor on the 6 months' postoperative computed tomography (group 1: 14% and group 2: 12%) and re-tear rate at 12 months (5% each) showed no difference between the 2 groups.

CONCLUSIONS

Shoulder function was improved after complete rotator cuff repair and similar clinical outcomes were achieved regardless of suture anchor material and shape. However, the open-construct PEEK anchor provided better bone ingrowth into the anchor than the non-vented biocomposite anchor at 6 months after arthroscopic rotator cuff repair.

LEVEL OF EVIDENCE

Level I; Prospective Randomized Trial.

Three anchor concepts for rotator cuff repair in standardized physiological and osteoporotic bone: a biomechanical study

BACKGROUND

Previous biomechanical studies used single-pull destructive tests in line with the anchor and are limited by a great variability of bone density of cadaver samples. To overcome these limitations, a more physiological test setting was provided using titanium, bioresorbable, and all-suture anchors.

METHODS

In this controlled laboratory study, 3 anchor constructs were divided into 2 groups: physiological and osteoporotic. Sixty standardized artificial bone specimens (=10 for each anchor in each group) were used for biomechanical testing. The anchors were inserted at a 45° angle as during surgery. Cyclic loading for 1000 cycles followed by ultimate load-to-failure (ULTF) testing was performed. Elongation, ultimate load at failure, and the mode of failure were noted.

RESULTS

In the physiological group, the ULTF for the all-suture anchor (mean [standard deviation], 632.9 [96.8 N]) was found to be significantly higher than for the other anchors (titanium, 497.1 [50.5] N, and bioresorbable, 322.4 [3.1 N], P < .0001). The titanium anchor showed a significantly higher ULTF than the bioresorbable anchor (P < .0001). In the osteoporotic group, the all-suture anchor again showed a higher ULTF compared to the bioresorbable anchor (500.9 [50.6] N vs. 315.1 [11.3] N, P < .0001). In the osteoporotic group, cyclic loading revealed a higher elongation after 1000 loading cycles for the bioresorbable (0.40 [0.12] mm) compared to the titanium (0.22 [0.11] mm; P = .01) as well as the all-suture anchor (0.19 [0.15] mm, P = .003).

CONCLUSION

Regarding ULTF, the all-suture anchor outperformed the other anchors in physiological bone, but in osteoporotic bone, significance was reached only compared to the bioresorbable anchor. Although cyclic loading revealed significant differences, these might not be clinically relevant.

Editorial Commentary: Fill It up: The Fate of "Absorbable" Implants

Surgeons make conscious decisions daily regarding implants. But do they really know what happens in the body to "absorbable anchors?" How long does it take to resorb, and what fills the space left behind? Absorbable materials can be very different, and well-done studies are important to help us understand the process and to guide our decisions.

The formation of perianchor fluid associated with various suture anchors used in rotator cuff repair

Aims

The aim of this study was to compare the osseous reactions elicited by all-suture, polyetheretherketone (PEEK), and two different biodegradable anchors used during rotator cuff repair.

Patients and Methods

Transosseous-equivalent rotator cuff repair was performed in 73 patients. The patients were divided into two groups, in both of which two different medial-row anchors were used. In group 1, anchor A comprised 30% β-tricalcium phosphate (TCP) + 70% fast-absorbing poly lactic-co-glycolic acid copolymer (85% polylactic acid enantiomers + 15% polyglycolic acid) and anchor B comprised all-sutures. In group 2, anchor C comprised 23% micro β-TCP + 77% polylactic acid enantiomers and anchor D comprised PEEK polymer. There were 37 patients in group 1 and 36 patients in group 2. The presence and severity of fluid collection around anchors and healing of the rotator cuff were assessed using MRI scans, approximately one year postoperatively. The severity of the collection was graded as 0 (no perianchor fluid signal), 1 (minimal perianchor fluid), 2 (local collection of fluid), 3 (fluid collection around the whole length of the anchor but of a diameter less than twice the anchor diameter), or 4 (fluid collection around the whole length of the anchor and of a diameter greater than twice the anchor diameter).

Results

A perianchor fluid signal was seen in three patients (8.1%) with anchor A, four (10.8%) with anchor B, 15 (41.7%) with anchor C, and 15 (41.7%) with anchor D. The severity of the collection around anchor was grade 2:1:0:0 for anchor A, grade 2:2:0:0 for anchor B, grade 12:2:0:1 for anchor C, and grade 11:3:0:1 for anchor D (grade 1:2:3:4, respectively). The prevalence and severity of fluid formation was not significantly different between anchors A and B, and anchors C and D. However, on intergroup analysis, there were significant differences for the prevalence and severity of fluid formation between anchors in group 1 and group 2. The prevalence of failure to heal was not significant in group 1 (seven, 18.9%) or group 2 (nine, 25.0%). There was no relationship between the presence of perianchor fluid and each type of anchor, and the integrity of the rotator cuff repair, in either group.

Conclusion

Despite the nonabsorbable nature of all-suture and PEEK anchors, all-suture anchors produced less osseous reaction after rotator cuff repair. In deciding which kind of anchor to use, consideration should be given not only to the strength of the initial fixation, but also to the postoperative biological reaction. Cite this article: Bone Joint J 2019;101-B:1506–1511

Editorial Commentary: Perianchor Cysts-We Need More Worries After Rotator Cuff Repair Like We Need Holes in the Head

Cysts or radiolucent rings are relatively common around suture anchors after rotator cuff repair. The rate of cyst occurrence is similar across anchor types and materials. Generally, perianchor cysts are benign and can be regarded as not affecting clinical outcomes.

Perianchor Cyst Formation After Arthroscopic Rotator Cuff Repair Using All-Suture-Type, Bioabsorbable-Type, and PEEK-Type Anchors

PURPOSE

This study aimed to identify the difference in postoperative perianchor bone reactions in different groups of patients who underwent rotator cuff tear repairs with all-suture-, bioabsorbable screw-, and PEEK (polyether ether ketone)-type suture anchors. Furthermore, the rate of rotator cuff retear and its association with perianchor bone reactions based on the different anchors used were investigated. Moreover, their impact on the clinical outcome of patients was examined.

METHODS

The study included 213 patients who underwent arthroscopic single-row repair and were divided into 3 groups according to the suture anchor used: all-suture (n = 137), biodegradable (n = 36), and PEEK (n = 40) anchor groups. The clinical outcomes and magnetic resonance imaging findings were evaluated at a mean follow-up of 9.6 months. The perianchor bone reaction at the anchor site was categorized according to grades. Patients were classified based on repair integrity into the healed and retear groups with Sugaya type I to III and Sugaya type IV to V, respectively.

RESULTS

No statistically significant differences in Constant scores and retear rates were observed between the groups (P = .934 and P = .548, respectively). Magnetic resonance imaging showed that the total number of perianchor cysts formed postoperatively was 23 (10.8% [23 of 213 patients]). Moreover, the proportions of perianchor cysts were 8.8%, 16.7%, and 12.5% in the all-suture-type, bioabsorbable-, and PEEK-type anchor groups, respectively (P = .485). In the retear group, the incidence rate was significantly increased with higher grades of perianchor bone reaction (P = .001). The tear size and perianchor bone reaction were found to be independent factors that affected the incidence of retear.

CONCLUSIONS

Perianchor cyst formation was observed in 10.8% of cases after the use of suture anchors for arthroscopic rotator cuff repair. No significant differences were observed among all-suture-type, bioabsorbable-type, and PEEK-type anchors in terms of visual analog scale and Constant scores, retear rates, and perianchor bone reactions. However, the retear rate was associated with a greater perianchor cystic reaction and larger tear size.

LEVEL OF EVIDENCE

Level III, retrospective comparative trial.

Biocomposite Suture Anchors Remain Visible Two Years After Rotator Cuff Repair

BACKGROUND

Biocomposite suture anchors containing osteoconductive materials have gained popularity in rotator cuff repairs. However, little is known about the influence of the addition of osteoconductive materials on implant resorption, bone reaction, tendon healing, and clinical outcomes scores.

QUESTIONS/PURPOSES

(1) What percentage of suture anchors were not completely resorbed 2 years after implantation? (2) What are the diameters of the bone bed in relation to the implant? (3) Is tendon integrity correlated with bone tunnel diameter? (4) Is there an association between tunnel widening, periimplant fluid film grade, biodegradation grade, and retear with clinical outcomes scores, such as the Western Ontario Rotator Cuff Index (WORC) and the Oxford Shoulder Score (OSS)?

METHODS

Thirty-six patients were enrolled from August 2012 to January 2014. The following inclusion criteria were applied: (1) reparable full-thickness supraspinatus tendon tears, (2) double-row suture bridge techniques applied for supraspinatus repair, (3) use of biocomposites suture anchor implants composed of poly L-lactic acid (PLLA) and β-tricalcium phosphate (TCP) exclusively, and (4) a minimum of 2 years followup. Four patients met the exclusion criteria, and seven of 36 patients (19%) were lost to followup. Thereby, 25 patients (84 implants) were included in this retrospective study. To answer the study's questions, the following methods were applied: (1) The resorption of the implants and periimplant fluid film were assessed on MRI using a four-stage scale system, (2) bone bed diameter was measured on MRI at three different points on the longitudinal central axis of each anchor, (3) tendon integrity was evaluated on MRI according to the Sugaya classification and correlated to bone tunnel diameter, and (4) assessed tunnel diameters, periimplant fluid film grade, biodegradation grade, and tendon condition were related to clinical outcomes scores at the time of followup (2.3 ± 0.3 years). The intraobserver reliability was 0.981 (p < 0.001) and interobserver reliability was 0.895 (p < 0.001).

RESULTS

At 2.3 ± 0.3 years, most analyzed suture anchors (76 of 84 [90%]) were, with varying degrees of degradation, still visible. Bone tunnels showed minor widening (0.4 ± 1.4 mm) at the base, but osseous ingrowth was detected as narrowing at the middle (0.1 ± 1.1 mm) and at the apex (1.4 ± 1.7 mm) of the implants. Patients with retears (Sugaya Grades 4-5) had narrower tunnels (3.6 ± 1.8 mm) than patients without retears (Sugaya Grades 1-3; 4.4 ± 1.6 mm; mean difference, 0.782 [95% confidence interval {CI}: 0.009-1.6]; p = 0.050). WORC and Oxford scores were not associated with the tunnel widening amount, fluid film grade, biodegradation grade, or tendon retear.

CONCLUSIONS

In light of the results of the present study, surgeons should consider in their daily practice that the resorption process of these implants may be slower than assumed so far, but no association with severe implant-related complications has been found in the short term. Future studies should focus on the evaluation of the effects of osteoconductive materials on resorption, tendon healing, and clinical outcomes in the long term and on the integration process in different rotator cuff reconstruction techniques.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Changes in Perianchor Cyst Formation Over Time After Rotator Cuff Repair: Influential Factors and Outcomes

BACKGROUND

There is a lack of knowledge about the changes in perianchor cysts over time and the factors related to perianchor cysts.

PURPOSE

To evaluate the changes in perianchor cyst formation and anchor absorption over time after arthroscopic rotator cuff repair with a biocomposite suture anchor and to evaluate the factors affecting perianchor cyst persistence and their relationship with patient outcomes.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Forty consecutive patients (mean age, 61.10 ± 5.79 years) who underwent arthroscopic repair for medium- to large-sized rotator cuff tears using a single type of biocomposite (poly-L-lactic acid/polyglycolic acid-beta tricalcium phosphate) medial-row anchor were prospectively enrolled. Postoperative magnetic resonance imaging (MRI) at 2 different time points (6 and 18 months) was performed, and perianchor cyst formation, anchor absorption, and healing failures were evaluated using postoperative MRI. Demographic and clinical data were collected, and functional outcomes at a minimum of 18 months after surgery were assessed.

RESULTS

Perianchor cysts were observed in 24 patients (60.0% total; grade 1: 35.0%; grade 2: 10.0%; grade 3: 7.5%; grade 4: 7.5%) at 6 months, and 7 patients (18.4% total; grade 1: 7.9%; grade 2: 5.3%; grade 3: 2.6%; grade 4: 2.6%) had a persistent perianchor cyst at 18 months after surgery. No anchors were absorbed at 6 months, but 73.7% of patients revealed complete or near-full absorption at 18 months. Patients with persistent perianchor cysts showed a significantly larger tear size in the anteroposterior dimension ( P = .002) and greater retraction ( P < .001). There were no differences in healing failures and functional outcomes between patients with and without persisting perianchor cysts (all P > .05). No differences were found in perianchor cyst formation and anchor absorption between anchors inserted in the greater tuberosity and the lesser tuberosity (all P > .05).

CONCLUSION

The incidence and severity of perianchor cysts decreased with time, and most biocomposite suture anchors were absorbed at 18 months after surgery. Persisting perianchor cysts correlated with a larger tear size in the anteroposterior dimension and greater retraction.

Pullout Strength of All-Suture Anchors: Effect of the Insertion and Traction Angle-A Biomechanical Study

PURPOSE

To evaluate the pullout strength of the all-suture anchor (ASA), based on the angles of anchor insertion and traction.

METHODS

Synthetic saw bones of 2 densities (0.16 and 0.32 g/cm³) with 3 mm thick cortical bone models were used. ASAs were inserted at 45°, 60°, 75°, or 90° and pulled at 2 angles from the surface: 45° (simulating the physiological pull of the supraspinatus) and 90° (simulating pulling out during knot tying). Five consecutive pullout tests for each insertion and traction angle combination per saw bone were conducted to evaluate the ultimate load to failure and mode of failure (80 tests total). Thereafter, 9 matched pairs of human cadaveric humeri with 2 ASA types were used (insertion angles, 45°, 75°, 90°; traction angle, 90°). Nine consecutive tests were conducted for each insertion angle and anchor type (54 tests total).

RESULTS

The pullout strength was significantly higher for high density- than for low-density saw bones (all P < .05). The pullout strength was higher at the 45°than at the 90° traction angle (all P < .05) and was significantly higher at the 90° and 75° than at the 45° insertion angle in both high-density saw bones and cadaveric humeri (all P < .05). However, the pullout strength was not significantly different by ASA type (all P > .05).

CONCLUSIONS

ASA showed stronger pullout strength in higher density bones. Furthermore, it presented stronger pullout strength in the physiological traction direction of supraspinatus rather than in the knot-tying direction, consistent with the deadman theory. However, stronger pullout strength was observed in the vertically directed insertion angle, not 45°. Therefore, implanting the ASA vertically may be clinically more beneficial not only when performing knot tying during surgery, but also when the supraspinatus tendon loads the ASA postoperatively.

CLINICAL RELEVANCE

The study provides biomechanical evidence that the optimal insertion angle for an ASA is more vertical than the 45°.

Clinical Outcomes of Arthroscopic Rotator Cuff Repair Using Poly Lactic-co-glycolic Acid Plus β-tricalcium Phosphate Biocomposite Suture Anchors

Background

This study is performed to evaluate anchor-related outcomes and complications after arthroscopic rotator cuff repair using 30% β-tricalcium phosphate (β-TCP) with 70% poly lactic-co-glycolic acid (PLGA) biocomposite suture anchors.

Methods

A total of 78 patients (mean age, 61.3 ± 6.9 years) who underwent arthroscopic medium-to-large full-thickness rotator cuff tear repair were enrolled. The technique employed 30% β-TCP with 70% PLGA biocomposite suture anchors at the medial row (38 patients, Healix BR^TM anchor [Healix group]; 40 patients, Fixone anchor B [Fixone group]). The radiologic outcomes (including perianchor cyst formation or bone substitution) and anatomical outcomes of the healing failure rate were evaluated using magnetic resonance imaging at least 6 months after surgery, the pain visual analogue scale at 3, 6 months, and final follow-up visit, and American Shoulder and Elbow Surgeons scores at least 1 year postoperatively. Anchor-related complications were also evaluated.

Results

The perianchor cyst formation incidence was similar for both groups (60.5%, Healix group; 60.0%, Fixone group; p=0.967), although severe perianchor cyst incidence was slightly lower in the Fixone group (15.0%) than in the Healix group (21.1%). There was no occurrence of anchor absorption and bone substitution. No differences were observed in the healing failure rate (13.2%, Healix group; 15.0%, Fixone group; p=0.815) and functional outcome between groups (all p>0.05). Anchor breakage occurred in 5 patients (2 Healix anchors and 3 Fixone anchors); however, there were no major anchor-related complications in either group.

Conclusions

No differences were observed in the clinical outcomes of the Healix and Fixone groups, neither were there any accompanying major anchor-related complications.