Biodegradable Suture Anchors Research Articles

Mechanical Properties and In Vitro Corrosion Behaviors of Biodegradable Magnesium Alloy Suture Anchors

Biodegradable suture anchors based on Mg-Nd-Zn-Zr alloy were developed for ligament-to-bone fixation in rotator cuff surgeries. The Mg alloy anchors were designed with structural features of narrow tooth and wide tooth, and simulated through finite element analysis (FEA). Meanwhile, the corrosion behaviors of the Mg alloy anchors were studied by immersion test and the mechanical properties were investigated by measuring the maximum torque and pull-out force. The simulation result showed that the wide-tooth anchor exhibited more a uniform stress distribution and lower shear stress in the torsion process, suggesting a satisfactory torsional resistance of this structure. Meanwhile, the wide-tooth anchor exhibited a lower Von-Mises stress after applying the same pull-out force in the simulation, indicating a higher resistance to pull-out failure of the anchor. The result of the immersion test indicated that the wide-tooth anchor exhibited a slightly slower corrosion rate in Hank’s solution after 14-day immersion, which was beneficial to enhance the structural and mechanical stability of the biodegradable suture anchor. Furthermore, the results of the mechanical properties test demonstrated that the wide-tooth anchor showed superior performance with higher maximum torques and axial pull-out forces before and after corrosion. More importantly, the axial pull-out force and maximum torque for the wide-tooth anchor decreased by 5.86% and 8.64% after corrosion, which were significantly less than those for the narrow-tooth anchor. Therefore, the wide-tooth suture anchor with lower corrosion rate, higher mechanical properties and structural stability is a promising candidate for ligament-bone fixation in the repair of rotator cuff injuries.

Biodegradable vs nonbiodegradable suture anchors for rotator cuff repair: a systematic review and meta-analysis.

The use of non-biodegradable suture anchors (NBSA) in arthroscopic rotator cuff repair (RCR) has increased significantly. However, several complications such as migration, chondral damage, revision, and imaging difficulties have been reported. Meanwhile, the effectiveness of biodegradable suture anchors (BSA) in overcoming such complications and achieving functional outcomes requires further study. Thus, we aim to compare the clinical outcomes and complications of RCR using BSA and NBSA using direct comparison studies. Two independent reviewers conducted systematic searches in PubMed, Embase, Cochrane Library, and Web of Science from conception to September 2022. Using the RoB 2 and ROBINS-I tools, we assessed the included studies for bias. We applied GRADE to appraise our evidence. Our PROSPERO registration number is CRD42022354347. Six studies (two randomized controlled trials, one retrospective cohort, and three case-control studies) involving 423 patients were included (211 patients received BSA and 212 patients received NBSA). BSA was comparable to NBSA in forward flexion, abduction, external rotation, Constant-Murley score, and perianchor cyst formation (P = 0.97, 0.81, 0.56, 0.29, and 0.56, respectively). Retear rates were slightly higher while tendon healing was reduced in BSA compared to NBSA, but the differences were not significant (P = 0.35 and 0.35, respectively). BSA and NBSA appear to yield similar shoulder functions and complications in rotator cuff repairs.

Comparative Evaluation of Metallic and Biodegradable Suture Anchors in Arthroscopic Repair of Anterior Talofibular Ligament Injury: A Short-term Study on Clinical and Functional Outcomes.

BACKGROUND With the development of arthroscopy and suture anchor, the modified Brostrӧm technique has made remarkable progress. However, it is unclear which material is most suitable for treating anterior talofibular ligament injury (ATFL). This study evaluated the short-term efficacy of 2 suture anchors (metal vs biodegradable materials) in arthroscopic ATFL repair. MATERIAL AND METHODS From January 2018 to December 2019, 82 patients with ankle disorders (51 men and 31 women) with ATFL injury received arthroscopic repair with suture anchor through the Brostrӧm-Gould procedure. The mean age was 38.70±9.35 years (range, 18-54 years). Each patient was followed up. American Orthopedic Foot and Ankle Society score (AOFAS), Karlsson Ankle Functional Score (KAFS), and the Visual Analogue Scale (VAS) were used to evaluate functional status and pain. RESULTS All patients were followed up for 21.21±2.19 months (range, 18-25 months). No complications were found either group. Preoperative clinical and functional scores in both groups had no significant difference (P>0.05). The functional score increased significantly in both groups (P<0.001). At the last follow-up, the mean AOFAS score was 93.00 (90.00, 96.00) in the Biodegradable group and 93.50 (91.00, 96.00) in the Metallic group (P=0.31). The mean KAFS score was 91.50 (85.00, 95.00) in the Biodegradable group and 93.00 (90.00, 95.50) in the Metallic group (P=0.10); the mean VAS score was 1.50 (1.00, 1.80) in the Biodegradable group and 1.30 (0.98, 1.70) in the Metallic group (P=0.22). CONCLUSIONS Arthroscopic repair of ATFL injury with suture anchors can improve the prognosis of CAI. There were no statistically significant differences in clinical and functional outcomes with metal or biodegradable suture anchors at short-term follow-up.

Knotless PEEK and double-loaded biodegradable suture anchors ensure comparable clinical outcomes in the arthroscopic treatment of traumatic anterior shoulder instability: a prospective randomized study

PurposeTo compare the clinical outcome of arthroscopic capsulolabral repair for traumatic anterior shoulder instability with PEEK knotless and knotted biodegradable suture anchors.MethodsArthroscopic stabilization was performed in 78 patients with recurrent traumatic anterior shoulder instability. They were divided into 2 groups of 39 patients each, according to suture anchors used: knotless PEEK anchors in group 1, and biodegradable anchors in group 2. Exclusion criteria were: instability without dislocation, posterior or multidirectional instability, glenoid bone loss > 20%, off-track lesions, concomitant rotator cuff tears and previous surgery. The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) self-administered questionnaire. Secondary outcomes were: Work-DASH, Sport-DASH, Rowe score, recurrent instability and subsequent surgery. The following independent variables were considered: age, gender, dominance, generalized ligamentous hyperlaxity, duration of symptoms, age at first dislocation, number of dislocations, type of work, type of sport, sports activity level, capsule-labral injury pattern, SLAP lesion and number of anchors. Differences between groups for numerical variables were analyzed by use of the Student’s t-test or Mann–Whitney U-test. Fisher’s exact test was used for analysis of categorical variables. Significance was set at p < 0.05.ResultsSeven patients (9%) were lost at follow-up, 5 from group 1 and 2 from group 2. Follow-up ranged from 36 to 60 months (median: 44; IQR: 13). Comparison between groups did not show significant differences for each independent variable considered. No differences could be found either for DASH (n.s.) or Rowe (p = n.s.) scores between the two groups. Overall recurrence rate was 7%. Three re-dislocations were reported in group 1 and two in group 2 (n.s.). Only one patient in each group underwent re-operation.ConclusionsThe study showed no significant differences in clinical outcomes after arthroscopic treatment of traumatic anterior shoulder instability using PEEK knotless or biodegradable knotted anchors at mid-term follow-up.Level of evidenceI.

Use of Ultrasonically Interdigitated Anchors in Haglund's Deformity Correction Surgery.

Haglund's deformity is a common cause of foot pain, with high success rates of surgical intervention. Because early weightbearing rehabilitation correlates with better surgical results, the integrity of anchors employed in these surgeries needs to be evaluated for proper fixation strength, leading to improved postoperative outcomes. The ultrasonically interdigitated anchor is a biodegradable suture anchor that is melted into bony trabeculae using ultrasound, leaving a small biological footprint and less interference on computed tomography and magnetic resonance imaging scans, without loss of fixation strength. We performed a review of 44 patients aged 26 to 84 years treated with either ultrasonically interdigitated anchors or fully threaded titanium anchors during Haglund's deformity excision. Overall, 7 of 14 patients who received an ultrasonically interdigitated anchor reported raw PROMIS (Patient-Reported Outcomes Measurement Information System) scores averaging 14.3, with an average return to ambulation time of 4.2 weeks. Fifteen of 30 patients receiving a fully threaded titanium anchor reported raw PROMIS scores averaging 9.7, with an average return to ambulation time of 3.5 weeks. We found little difference between the outcomes between the 2 anchors and no massive failures or infections in either group, implying that ultrasonically interdigitated anchors are a viable option for Achilles tendon reattachment during Haglund's deformity repair surgery.Levels of Evidence: Level III: Case control study.

Metallic versus biodegradable suture anchors for rotator cuff repair: a case control study

BackgroundsRepair of full-thickness rotator cuff (RC) tears is routinely performed using suture anchors, which produce secure and effective soft tissue fixation to bone. The aim of this prospective study is to compare the long-term outcomes of single row arthroscopic rotator cuff repair (RCR) performed using metal or biodegradable suture anchors. The null hypothesis is that there is no difference in shoulder function using metal or biodegradable suture anchors as evaluated by UCLA shoulder score, Wolfgang criteria, and Oxford shoulder score.MethodsArthroscopic RCR was performed in 110 patients included in this case control study. They were divided into 2 groups of 51 and 59 patients respectively. Metal suture anchors were used in group 1, and biodegradable suture anchors in group 2. Results were obtained at a mean follow up of 4.05 + 2 years. Clinical outcomes and functional outcomes were evaluated.ResultsThe mean modified UCLA shoulder score was 26.9 + 7.1 in group 1, and 27.7 + 6.5 in group 2 (P = 0.5); the mean Wolfgang score was 13.3 + 3.3 in group 1, and 14 + 2.6 in group 2 (P = 0.3); the mean OSS was 23.7 + 11.4 in group 1, and 20.7 + 9.2 points in group 2 (P = 0.1). The mean active anterior elevation was 163.5° + 28.2° in group 1 and 163.6° + 26.9 in group 2 (P = 0.9); the mean active external rotation was 46° + 19.7° in group 1 and 44.6° + 16.3° in group 2 (P = 0.7). The mean strength in anterior elevation was 4.8.02 + 23.52 N in group 1, and 43.12 + 17.64 N in group 2 (P = 0.2); the mean strength in external rotation was 48.02 + 22.54 N in group 1 and 46.06 + 17.64 N in group 2 (P = 0.6); the mean strength in internal rotation was 67.62 + 29.4 N in group 1, and 68.6 + 25.48 N in group 2 (P = 0.9).ConclusionsThere are no statistically significant differences at a mean follow-up of 4.05 + 2 years in clinical and functional outcomes of single row arthroscopic RCR using metallic or biodegradable suture anchors for RC < 5 cm.

Clinical and Radiological Outcomes After Arthroscopic Bankart Repair Using the All-Suture Anchors: Comparison with the Biodegradable Suture Anchors

Clinical and Radiological Outcomes After Arthroscopic Bankart Repair Using the All-Suture Anchors: Comparison with the Biodegradable Suture Anchors

Comparison of Clinical Outcomes and Computed Tomography Analysis for Tunnel Diameter After Arthroscopic Bankart Repair With the All-Suture Anchor and the Biodegradable Suture Anchor

To compare the clinical outcomes and radiological findings at the anchor site after arthroscopic Bankart repair with all-suture anchors and biodegradable suture anchors in patients with recurrent anterior shoulder dislocation. The patients who underwent arthroscopic Bankart repair were divided into 2 groups depending on the type of the suture anchor used in different periods. Power analysis was designed based on the postoperative Rowe score. Clinical outcomes, including the Rowe score, American Shoulder and Elbow Surgeons score, subjective instability, and redislocation rates were evaluated. In all patients enrolled, the tunnel diameter of the anchor was assessed with computed tomography arthrogram at 1year postoperatively. The Institutional Review Board of Ewha Womans University approved this study (no. EUMC 2017-05-058). A total of 67 patients were enrolled: 33 underwent surgery with a 1.3-mm (single-loaded) or 1.8-mm (double-loaded) all-suture anchor (group A), and 34 underwent surgery with a 3.0-mm biodegradable anchor (10.8mm in length, 30% 1,2,3-trichloropropane/70% poly-lactide-co-glycolic acid) (group B). There were no significant differences in clinical outcomes between groups A and B in the American Shoulder and Elbow Surgeons score (preoperatively, 51.2 ± 13.7 vs 47.7 ± 12.2; 2years postoperatively, 88.5 ± 12.3 vs 89.7 ± 10.9; P= .667) and Rowe score (preoperatively, 41.4 ± 10.5 vs 41.3 ± 9.4; 2years postoperatively, 87.9 ± 14.9 vs 88.5 ± 14.6; P= .857). Postoperative redislocation (6.1% vs 5.9%, P= .682) and subjective instability rate (12.2% vs 17.7%, P= .386) of both groups showed no significant difference. Average tunnel diameter increment was significantly greater with the 1.8-mm all-suture anchor (2.8 ± 0.9mm) than the 1.3-mm all-suture anchor (1.2 ± 0.8mm) and 3.0-mm biodegradable anchor (0.8 ± 1.2mm)(P < .001). Arthroscopic Bankart repair with the all-suture anchor showed comparable clinical outcomes and postoperative stability as the conventional biodegradable suture anchor at 2years after surgery. Tunnel diameter increment of the all-suture anchor was significantly greater than that of the biodegradable suture anchor at the 1-year computed tomography analysis. Although tunnel diameter increment was greater with the all-suture anchor, it did not influence the clinical outcomes. Level III, retrospective comparative study.

Avulsion fracture of the ischial tuberosity treated with the suture bridge technique: a case report

BackgroundIn cases of avulsion fracture of the ischial tuberosity in which the bone fragments are substantially displaced, nonunion may cause pain in the ischial area. Various surgical procedures have been reported, but achieving sufficient fixation strength is difficult.Case presentationWe treated a 12-year-old male track-and-field athlete with avulsion fracture of the ischial tuberosity by suture anchor fixation using the suture bridge technique. The boy felt pain in the left gluteal area while running. Radiography showed a left avulsion fracture of the ischial tuberosity with approximately 20-mm displacement. Union was not achieved by conservative non-weight-bearing therapy, and muscle weakness persisted; therefore, surgery was performed. A subgluteal approach was taken via a longitudinal incision in the buttocks, and the avulsed fragment was fixed with five biodegradable suture anchors using the suture bridge technique.ConclusionsAlthough the majority of avulsion fractures of the ischial tuberosity can be treated conservatively, patients with excessive displacement require surgical treatment. The suture bridge technique provided secure fixation and enabled an early return to sports activities.

Two Cases of Biodegradable Suture Anchor Displacement Diagnosed with Ultrasonography following Arthroscopic Rotator Cuff Repair

With the advancement of shoulder arthroscopy, use of biodegradable suture anchors in the surgical repair of rotator cuff tears has increased. Because of the radiolucency of these anchors, radiography is not appropriate for early detection of anchor failure. Ultrasonography is an advantageous modality in visualizing biodegradable, radiolucent anchors on a real-time basis without risk of radiation exposure. We report on two cases of displacement of a biodegradable suture anchor diagnosed on ultrasonography during the postoperative follow-up, which has not been previously reported. Because this displacement could be missed in the postoperative follow up ultrasonography, we describe the ultrasonographic features of the displaced biodegradable anchors. Surgeons and radiologists should pay special attention to the possibility of displacement of the suture anchor in patients who underwent rotator cuff repairs using suture anchors.

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

Background: Biodegradable anchors may lead to perianchor cyst formation or osteolysis. A new generation of anchors containing osteoconductive material was recently presented, but there is currently no solid evidence that this concept decreases cyst formation around anchors. Hypothesis: The null hypothesis was that the prevalence and severity of cyst formation around anchors would be similar for all 3 anchor types. Study Design: Cohort study; Level of evidence, 2. Methods: To evaluate differences between anchor behaviors postoperatively, this study included 2 groups of patients who underwent rotator cuff repair. In group 1 (n = 38), transosseous-equivalent rotator cuff repair was performed in all patients. At the time of repair, 2 different anchors (anchor A: 23% microstructured β-tricalcium phosphate plus 77% polylactic acid enantiomers [PLLA]; and anchor B: 30% hydroxyapatite plus 70% PLLA) were used for medial-row repair. Insertion locations (anterior or posterior) were randomly assigned. In group 2 (n = 38), the same procedure was performed; however, 1 of the anchors used in group 1 was changed (anchor A: as above; and anchor C: 30% β-tricalcium phosphate plus 70% faster absorbing polylactic-co-glycolic acid copolymer [85% PLLA plus 15% polyglycolic acid]). The presence and severity of fluid collection around the anchors was evaluated by magnetic resonance imaging at approximately 1 year after rotator cuff repair (12.7 ± 0.9 months for group 1 and 12.6 ± 1.8 months for group 2). Results: In group 1, a fluid signal was observed in 14 patients (36.8%) for anchor A and in 12 patients (31.6%) for anchor B (P > .05). The severity of perianchor cyst formation was no different for the 2 anchors (respective fluid signal grades [0-4]: 24, 3, 9, 1, and 1 for anchor A; and 26, 4, 7, 1, and 0 for anchor B; P > .05). However, in group 2, cysts were observed in 19 patients (50%) for anchor A and in 3 patients (7.9%) for anchor C (P < .001). For anchor C, only 2 cases of grade 1 and 1 case of grade 2 fluid collection were observed. Intergroup analysis of anchor A revealed no significant differences in the prevalence or severity of perianchor cyst formation (P > .05). Healing failure was observed in 12 patients (31.6%) in group 1 and 10 patients (26.3%) in group 2 (P > .05). Conclusion: New-generation biodegradable suture anchors seem to decrease the severity of perianchor cyst formation. Future research is required to optimize the compositions and proportions of osteoconductive materials and polymers to improve adverse reactions. Nevertheless, controlling the properties of polymers and adding osteoconductive material both appear to enhance biocompatibility.

Adverse Events Associated With Biodegradable Lactide-Containing Suture Anchors

To evaluate the occurrence of adverse events and inflammatory reactions related to the use of biodegradable anchors. A retrospective review of a consecutive series of arthroscopic shoulder procedures using biodegradable suture anchors performed by a single surgeon was undertaken. The database was purged of patient identifiers. The blinded data were analyzed for procedure type, anchor type and composition, associated procedures, and general demographic data. Anchor composition and number were recorded. A shoulder procedure after the index operation was considered an adverse event. The nature of these procedures was evaluated using medical records, operative images, and video, looking specifically for inflammatory reactions. Any anchor-related issues were documented. Three hundred sixty cases met the inclusion criteria. The procedure was a tendon repair (rotator cuff or biceps) in 265 cases and a labral repair (instability or SLAP) in 97, 2 of which were combined instability and tendon repairs. Nine different biodegradable anchors were identified, possessing 4 different polymer combinations. Adverse events (reoperations) were identified in 18 of 360 patients (5%): 13 tendon repairs and 5 labral/instability repairs. Only 2 were anchor related. In 1 tendon repair case, the anchor broke and an anchor fragment required removal. In 1 labral repair case, the anchor eyelet (a suture) loosened from the anchor body and eroded the humeral head. No cases of inflammatory synovitis wereobserved. No statistical difference in adverse event rates existed between tendon and labral repairs (P > .05). Anchor-specific adverse events occurred in 2 of 360 procedures (0.5%). One was anchor design related (the prominent head containing the suture eyelet broke off) in a poly-L-lactic acid (PLLA) anchor. One was anchor material related and occurred when the poly-levo (70%)/dextro (30%)-lactide anchor body reabsorbed, loosening the encased eyelet suture and allowing this suture to migrate into the joint. No inflammatory reactions were documented in the slowly degrading pure PLLA or more rapidly degrading biocomposite PLLA/β-tricalcium phosphate-based anchors. Level IV, retrospective review, therapeutic study.

Computed Tomographic Analysis of Arthroscopic Labral Repair Using Absorbable Knotless Suture Anchors

Background We investigated the reconstitution of the glenoid bone after degradation of absorbable knotless suture anchors used for labral repair. Methods Arthroscopic labral repairs performed on 59 shoulders in 55 patients by a single surgeon using knotless poly-L-lactic acid suture anchors were reviewed at a mean of 46.5 months. Computed tomographic scans of the operated shoulder were reviewed by two independent radiologists for the number of drill holes present, as well as the amount of bony reconstitution and the presence of osteoarthritis. Results One hundred and ninety anchors were placed and both radiologists counted 185 drill holes (97%). Agreement between the radiologists was high (kappa = 0.96). The majority of holes had partial bony ingrowth (69% to 71%) and osteolysis was infrequent (6%). The prevalence of degenerative joint disease was 7% to 8%. Conclusions Biodegradable suture anchors are a viable option for labral fixation during arthroscopic shoulder stabilization but, in most cases, the drillholes are not fully replaced with bone and may enlarge, although the effect on clinical outcome is uncertain.

Relationship Between Insertion Torque, and Pullout Strength Depending on the Size of the Pilot Hole and Biodegradable Suture Anchor in Osteoporotic Humeral Head

PURPOSE: The object of this study was to investigate the difference in torque and pullout strength between the standard anchor insertion (5.0 mm) with a small awl (3.7 mm) and larger anchor insertion (6.5 mm), with a standard awl (5.0 mm) in osteoporotic humeral head.MATERIALS AND METHODS: The embalmed 24 paired cadaveric shoulders were assigned to either Group A or B. After measuring the bone mineral density (BMD) of the ROI (region of interest) in the humeral head, 5.0 mm suture anchors were inserted using a 3.7 mm awl in Group A1, and the same 5.0 mm anchors were inserted using a 5.0 mm awl in Group A2. The 5.0 mm anchors were inserted using a 5.0 mm awl in Group B1, and 6.5 mm anchors were inserted using a 5.0 mm awl in Group B2. We measured the torques at the time of the anchor insertion and pullout strengths.RESULTS: There was no significant difference in the BMD between the groups. The torque of A1 (20.6 cN.m) was significantly higher than that of A2 (13.2 cN.m), and the torque of B2 (20.8 cN.m) was significantly higher than that of B1(12.1 cN.m). However, the difference in the increased torque between group A and B was not significant. The pullout strength of A1 (204.2 N) was significantly higher than that of A2 (152.9 N), and the pullout strength of B2 (210.9 N) was significantly higher than that of B1 (149.5 N). However, the difference in the increased pullout strength between Group A and B was not significant.CONCLUSION: In severe osteoporosis, the use of a larger suture anchor with a standard awl increased the torque and pullout strength significantly, in comparison to the use of the same sized suture anchor and awl. If there is an inadequate interval between the anchors on the greater tuberosity, the use of a 3.7 mm awl and 5.0 mm anchor will be beneficial compared to that of a 5.0 mm awl and 6.5 mm anchor, considering that an increase in the pullout strength does not depend on the awl size.

Arthroscopic Rotator Cuff Repair With Metal and Biodegradable Suture Anchors: A Prospective Randomized Study

The purpose of this study was to compare the clinical outcome of arthroscopic rotator cuff repair with metal and biodegradable suture anchors. Arthroscopic rotator cuff repair was performed in 110 patients with a full-thickness rotator cuff tear. They were divided into 2 groups of 55 patients each, according to suture anchors used: metal anchors in group 1 and biodegradable anchors in group 2. Results were evaluated by use of the Disabilities of the Arm, Shoulder and Hand (DASH) and Work-DASH self-administered questionnaires, as well as the Constant score normalized for age and sex. On analyzing the results at 2 years' follow-up, we considered the following independent variables: baseline scores; age; sex; arm dominance; location, shape, and retraction of cuff tear; fatty degeneration; treatment of biceps tendon; rotator cuff repair technique (anchors or anchors and side to side); and number of anchors. Univariate and multivariate statistical analyses were performed to determine which variables were independently associated with the outcome. Significance was set at P < .05. Of the patients, 9 (8.2%) were lost to follow-up. Comparison between groups did not show significant differences for each variable considered. Overall, according to the results, the mean DASH scores were 17.6 +/- 17.2 points in group 1 and 22.8 +/- 19.9 points in group 2; the mean Work-DASH scores were 24.9 +/- 28.1 points and 22.5 +/- 24.1 points, respectively; and the mean Constant scores were 104 +/- 20.5 points and 98.6 +/- 14.3 points, respectively. Differences between groups 1 and 2 were not significant. Univariate and multivariate analysis showed that only baseline score, age, tear location, and fatty degeneration significantly and independently influenced the outcome. At a short-term follow-up, differences between arthroscopic repair of full-thickness rotator cuff tears with metal and biodegradable suture anchors were not significant. Level I, high-quality randomized controlled trial with no statistically significant differences but narrow confidence intervals.

Comparison between metal and biodegradable suture anchors in the arthroscopic treatment of traumatic anterior shoulder instability: a prospective randomized study

The purpose of this study was to compare the clinical outcome of arthroscopic treatment of shoulder instability with metal and biodegradable suture anchors. Arthroscopic stabilization was performed in 78 patients with recurrent traumatic anterior shoulder instability. They were divided into 2 groups of 39 patients each, according to suture anchors used: metal anchors in group 1, and biodegradable anchors in group 2. Results were evaluated by use of the Disabilities of the Arm, Shoulder and Hand (DASH) self-administered questionnaire; Rowe score; Constant score normalized for age and gender, and recurrence of dislocation. On analyzing the results at a 2-year follow-up, we considered the following independent variables: age; gender; arm dominance; duration of symptoms, age at first dislocation, number of dislocations, type of work; type of sport; sports activity level; lesion of the anterior labrum and anterior-inferior gleno-humeral ligament; SLAP lesion, and number of suture anchors. Comparison between groups did not show significant differences for each variable considered. Overall, according to the results, median DASH scores were 4.5 points (range 0-27) in group 1 and 7 points (range 0-25) in group 2 (n.s.); median Rowe scores were 100 points (range 60-100) and 100 points (range 25-100), respectively (n.s.); and median Constant scores were 98 points (range 81-107) and 98 points (range 87-121), respectively (n.s.). Recurrence was observed in 1 patient (2.8%) in group 1 and in 2 patients (5.9%) in group 2. Overall recurrence rate was 4.3%. Univariate and multivariate analysis showed that age, duration of symptoms, number of dislocations, type of work, and type of sports significantly and independently influenced the outcomes. Differences between groups 1 and 2 were not significant. At a short-term follow-up, differences between arthroscopic shoulder stabilization with metal and biodegradable suture anchors were not statistically significant. Clinical relevance of the study is that there is no difference in the use of metal or biodegradable suture anchors for the arthroscopic treatment of shoulder instability.

Enlargement of Drill Holes After Use of a Biodegradable Suture Anchor: Quantitative Study on Consecutive Postoperative Radiographs

Osteolysis around a biodegradable device has been warned of in several reports. We investigated variations of drill holes of polylactic acid (PLA) suture anchors in consecutive radiographs after arthroscopic capsulolabral repair to assess the influence of enlargement of the drill holes on clinical outcome. Twenty patients who underwent arthroscopic capsulolabral repair using 3 Panalok suture anchors for traumatic anterior shoulder instability were included in the study. The mean follow-up period was 25.8 months. From radiographs taken on postoperative day 1, at 3 and 12 months, and at the latest follow-up, the diameter of each drill hole was measured. The diameter enlargement ratio was calculated for each drill hole by dividing each diameter by the corresponding day-1 diameter. The patients were divided into 2 groups based on the degree of enlargement of drill holes (greater or less than the mean + 1 standard deviation [SD]) and the clinical outcome of each group was evaluated according to the Rowe score and range of motion. Diameter enlargement ratios tended to increase with time (P = .0152 for 3 v 12 months postoperatively, and P = .0049 for 3 v latest follow-up). Three drill holes out of 53, 17 out of 60, and 11 out of 47 showed enlargement over the mean + 1 SD, at 3 and 12 months postoperatively and at latest follow-up, respectively. Eleven patients had such enlarged drill holes, and had significantly poor Rowe score (70.9 v 95.6 points; P = .0267) at latest follow-up. A drill hole filled with a PLA anchor tended to enlarge over time. We found that 55% of patients had at least 1 drill hole that enlarged beyond the mean + 1 SD. These patients had significantly less favorable results in function and stability. The present study raises concern about the use of PLA suture anchors for the fixation of detached glenoid labrum. Level IV, therapeutic case series.

Isolated and combined Type II SLAP repairs in a military population

The study compares the clinical results of isolated arthroscopic repair of Type II SLAP tears with those of combined treatment for Type II SLAP and other associated shoulder conditions. The population was composed of 36 aged-matched active duty males with a mean age of 31.6 years (range 22-41 years); mean follow-up was 29.1 months (range 24-42 months). Eighteen subjects in Group I had isolated Type II SLAP tears. Eighteen subjects in Group II had Type II SLAP tear and concomitant ipsilateral shoulder conditions, including subacromial impingement in six patients, acromioclavicular arthrosis in three patients, subacromial impingement and acromioclavicular arthrosis in four patients, spinoglenoid cyst in four patients, and intra-articular loose bodies in one patient. Arthroscopic SLAP repair was performed with biodegradable suture anchors. Subacromial decompression and spinoglenoid cyst decompression were performed arthroscopically. Distal claviculectomy was performed in open fashion. Loose bodies were removed arthroscopically. At minimum 2-year follow-up, the mean UCLA score for Group I (30.2 +/- 3.0 points) was not significantly different from Group II (30.8 +/- 2.0 points) (P = 0.48). The mean post-operative ASES score for Group I (84.1 +/- 13.4 points) was significantly lower than for Group II (91.8 +/- 5.4 points) (P < 0.04). The mean VAS pain score for Group I (1.6 +/- 1.3 points) was significantly higher than for Group II (0.7 +/- 0.7 points) (P < 0.02). Seventeen of 18 patients (94%) in each group returned to full duty. In a population of active duty males, arthroscopic repair of isolated Type II SLAP had comparable results with a cohort of Type II SLAP repairs treated in combination with other shoulder conditions, with the combined treatment group having significantly better results in two of three parameters measured. Return to duty rates were identical. Therefore, concurrent treatment of other associated extra-articular shoulder conditions improves the overall success of SLAP repair and the presence of these other conditions should be recognized and treated along with the SLAP tears in order to maximize clinical results.

Cyclic Load Testing of Biodegradable Suture Anchors Containing 2 High-Strength Sutures

The purpose of this study was to test 4 different biodegradable suture anchors threaded with 2 high-strength sutures under cyclic loading conditions in humeral cadaveric specimens divided into 2 different age groups. Thirty-two paired human cadaveric humeri were stripped of all soft tissue. Two groups were studied: group 1, in which the mean age was 54 years, and group 2, in which the mean age was 70 years. We placed 1 suture anchor at 3 humeral sites per bone (anterior, middle, and posterior greater tuberosity). We tested 24 specimens using each of 4 anchors: TwinFix AB (Smith & Nephew Endoscopy, Andover, MA), BioZip (Stryker Endoscopy, San Jose, CA), Bio-Corkscrew FT (Arthrex, Naples, FL), and SpiraLok (DePuy Mitek, Raynham, MA). The anchor's sutures were grasped with an Instron clamp (Instron, Canton, MA), preloaded, and cycled from 10 to 60 N 500 times, followed by destructive testing. The mean displacement at 500 cycles, yield loads, failure modes, and ultimate loads were recorded. Most cyclic motion occurred during the first 100 cycles. More motion occurred in older bones than in younger bones (P < .05). The mean yield loads were greater for the young group for the SpiraLok anchors than for Bio-Corkscrew FT anchors in the young and old groups (P < .001), TwinFix anchors in the old group (P < .05), and BioZip anchors in the old group (P < .05). The ultimate failure loads for SpiraLok anchors in the young group were greater than for Bio-Corkscrew FT anchors in the young and old groups and BioZip anchors in the old group (P < .05). In group 1 TwinFix AB (P = .01) and BioZip (P = .02) ultimate loads were statistically greater than that for Bio-Corkscrew FT. The TwinFix AB failed by anchor pullout. The Bio-Corkscrew FT failed by eyelet pullout. The BioZip and SpiraLok pulled out in older bone and experienced eyelet breakage in younger bone. None of the 4 anchors reached 5 mm of displacement even after 500 loading cycles. Most of the displacement occurred in the first 100 cycles. Of all anchors tested, the Bio-Corkscrew FT recorded the lowest displacement after 500 cycles (P < .05). The SpiraLok had the highest ultimate load of all anchors tested (P < .01). Rotator cuff anchors perform differently in younger humeral bone than in older humeral bone. Most displacement with cyclic loading occurring between the anchor and bone takes place in the first 100 cycles. Anchors in older bones can be expected to fail at lower loads.

Biodegradable Shoulder Anchors Have Unique Modes of Failure

Biodegradable suture anchors have facilitated and revolutionized arthroscopic tissue-to-bone repair, especially in the shoulder. However, the anchor is but a part of the repair construct, which also includes a suture, tied in a knot, that attaches the tissue (tendon or labrum) to bone. Bioabsorbable anchors may result in loose bodies. Two cases are reported as sentinel events highlighting this potential risk. In the first case, combining a nonabsorbable suture (forming the anchor eyelet) with an anchor body made from rapidly degrading copolymer resulted in the suture becoming a loose body as the anchor body reabsorbed. In the second case, a portion of the eyelet and upper screw thread, itself composed of a biodegradable copolymer, became a loose body as the anchor absorbed, perhaps because the eyelet became proud with regard to the host bone during cyclic loading. Biodegradable anchors offer many advantages over metal anchors but do not eliminate the risk of a glenohumeral loose body. Unexpected postoperative symptoms such as painful catching, popping, or “squeaking” may indicate a glenohumeral loose body and warrant an arthroscopic evaluation. In the future, improved shoulder suture anchor design may lower the risk of this complication.