A biomechanical comparison of a mesh suture to a polyblend suture in a porcine tendon model

Association of obesity with high retears and complication rates, and low functional scores after rotator cuff repair: a systematic review and meta-analysis

BACKGROUND

Obesity influences the outcomes of orthopedic surgeries such as total knee arthroplasty and spinal surgery. However, the effect of obesity on the outcomes of rotator cuff repair is unknown. This systematic review and meta-analysis aimed to examine the effect of obesity on rotator cuff repair outcomes.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched to identify relevant studies published from their inception till July 2022. Two reviewers independently screened titles and abstracts using the specified criteria. Articles were included if they indicated the effect of obesity on rotator cuff repair and the related outcomes after surgery. Review Manager 5.4.1 software was used to perform statistical analysis.

RESULTS

Thirteen articles involving 85,497 patients were included. Obese patients had higher retear rates than nonobese patients (odds ratio [OR] 2.58, 95% confidence interval [CI] 1.23-5.41, P = .01), lower American Shoulder and Elbow Surgeons scores (mean difference [MD]: -3.59, 95% CI: -5.45 to [-1.74]; P = .0001), higher visual analog scale for pain (mean difference: 0.73, 95% CI: 0.29-1.17; P = .001), higher reoperation rates (OR 1.31, 95% CI 1.21-1.42, P < .00001), and higher rates of complications (OR 1.57, 95% CI 1.31-1.87, P = .000). Obesity did not affect the duration of surgery (MD: 6.03, 95% CI: -7.63 to 19.69; P = .39) or external rotation of the shoulder (MD: -1.79, 95% CI: -5.30 to 1.72; P = .32).

CONCLUSION

Obesity is a significant risk factor for retear and reoperation after rotator cuff repair. Furthermore, obesity increases the risk of postoperative complications and leads to lower postoperative American Shoulder and Elbow Surgeons scores and higher shoulder visual analog scale for pain.

Biomechanical effect of increased number of suture strands on rotator cuff repair in a bovine model

OBJECTIVE

This study aimed to investigate if there was a link between the biomechanical properties and the number of suture strands in repairing a rotator cuff (RC) tear in a bovine model using the transosseous technique.

METHODS

Fifty-four fresh tendons from bovine (mean age: 7.1 ± 0.5 months; range 6.5-7.5 months) and 1 humeral head from porcine (8.5 months) were used in this study. All the specimens had no apparent abnormalities. Using the transosseous structure, the RC tendon was detached from the greater tuberosity and randomly assigned to 3-strand, 4-strand, 5-strand, and 6-strand groups, with the glenohumeral abducted at 0° and 90°. Biomechanical tests were conducted to compare the groups' differences in the failure mode, pull-toextension load in the 1-, 2-, and 3-mm formations, and the maximum load. The analysis of variance test was performed to compare the results. Statistical significance was set at P < .05.

RESULTS

No significant difference was observed among the groups concerning the tendon characteristics (all P ≥ .05). At 90° shoulder abduction, a significant difference was detected in the load between 3- and 5-strand groups for 1-mm gap formation (P=.049). No statistical differences were noted in the load at the gap displacements in the 1-, 2-, and 3-mm formations at 0° and 90° shoulder abduction (all P > .05). The maximum failure load and extension in maximal tension increased with the number of sutures.

CONCLUSION

The maximum load and ultimate extension increase with the number of sutures at both positions. The number of sutures was not an influencing factor of gap formation. Regarding the tear size and tension of the RC, choosing the appropriate number of strands individually instead of excessively increasing the number of sutures is advocated for RC repair.

A Transosseous Suture as an Alternative to Suture Anchor on Anterior-Avulsion Greater Tuberosity Fragment Fixation in Neer Three-Part Proximal Humeral Fracture: A Biomechanical Study

OBJECTIVE

Greater tuberosity (GT) fragments were communicated, and additional techniques to increase the GT fragment stability after the locking plate fixation was necessary. This study aimed to analyze the reinforcement effects on the anterior-avulsion GT fragment in Neer three-part proximal humeral fractures (PHFs) using transosseous suture and suture anchor techniques.

METHODS

Eighteen fresh-frozen human cadaveric shoulder specimens were used in the study. Standardized fracture of the GT and surgical neck was created in 18 human cadaveric proximal humerus. The GT fragments were reinforced with transosseous suture (TS), suture anchor (SA), and suture in addition to the PHILOS plate fixation. The fixed humerus was tested by applying static loading to the supraspinatus tendon. Load forces and fragment displacement were evaluated by a biomechanical testing machine, and the load to 3- and 5-mm displacements, load to failure, and mode of failure were recorded for all specimens. Nonparametric variables were examined by the Kruskal-Wallis test, and the Bonferroni post hoc test was used to analyze the mean loads to create 3- and 5-mm displacements as well as the failure load.

RESULTS

The age, female proportion, and bone mineral density showed no statistically significant differences between the three groups. The mean loading force to create 3-mm and 5-mm displacement in the TS group (254.9 ± 77.4, 309.6 ± 152.7) were significantly higher than those in the suture group (136.1 ± 16.7, 193.4 ± 14.5) (P = 0.024, P = 0.005). For the SA group, the force to create 3- and 5-mm displacement (204.3 ± 60.9, 307.8 ± 73.5) were comparable to those in the TS group (P = 0.236, P = 0.983). Moreover, the loading force to failure in the TS group (508.6 ± 217.7) and SA group (406.6 ± 114.9) was significantly higher than that in the suture group (265.9 ± 52.1) (P = 0.021, P = 0.024). In the TS group, three failed due to tendon-bone junction rupture; bone tunnel broken occurred in two specimens; suture rupture could also be seen in one specimen. All specimens in the suture group failed because of suture rupture. In the SA group, three specimens failed due to suture rupture; two failed secondary to tendon-bone junction rupture; and one failed because of shaft fracture.

CONCLUSIONS

Transosseous suture is a new type of reinforcement for GT fragment in Neer-three part PHFs. The transosseous suture was superior to the suture only in the reinforcement of the anterior-avulsion GT fragment of Neer three-part PHFs, and it had comparable biomechanical strength to the suture anchor.

Does the Fatty Infiltration Influence the Re-tear Rate and Functional Outcome After Rotator Cuff Repair? A Systematic Review and Meta-analysis

Purpose

Fatty infiltration (FI) of the rotator cuff muscles occurs after rotator cuff tears (RCTs), which may affect the outcome of the repair procedure. This study aimed to determine the relationship between preoperative FI and the rate of re-tear and functional outcomes after rotator cuff repair.

Methods

Computerized databases, including PubMed, EMBASE, Web of Science, and Cochrane Library database were searched for studies published from the inception date to January 2022. Two reviewers independently screened the titles and abstracts using prespecified criteria. Articles were included if they clearly stated the effect of varying degrees of FI on the outcome after shoulder cuff repair. Comparison was performed by different degrees of FI analysis: no FI is grade 0-1, FI is grade 2 and above. Statistical analysis was performed using Review Manager 5.4.1 software.

Results

A total of 16 articles involving 1383 patients from 8 countries were included. The follow-up period ranged from 8 to 121 months. In terms of re-tear rate: patients with preoperative FI had significantly higher rates of re-tear compared with patients without FI (OR 4.60, 95% CI 2.22-9.54, p < 0.0001), supraspinatus FI VS no FI (OR 2.06, 95% CI 1.00-4.24, p = 0.05), infraspinatus FI VS no FI (OR 2.42, 95% CI 1.19-4.91, p = 0.01). In terms of functional scoring: patients without FI had higher postoperative Constant-Murley (Constant) scores than those with FI (MD - 5.06, 95% CI - 9.40 to - 0.72, p = 0.02), there was no clear evidence that preoperative FI was related to postoperative American Society of shoulder and elbow physicians scores and the University of California at Los Angeles scores and range of motion.

Conclusion

FI after RCTs significantly increases the risk of postoperative re-tear and leads to worse functional scores, especially FI of the infraspinatus muscle. However, FI does not seem to reduce postoperative range of motion.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-022-00807-0.

Three Medial All Suture Anchors Improves Contact Force Compared to Two Hard Body Anchors in a Biomechanical Two-Tendon Rotator Cuff Tear Model

Purpose

To biomechanically compare a knotless double-row construct with 3 medial all-suture (3AS) anchors with a standard 2 medial hard body (2HB) anchor construct.

Methods

Twelve matched cadaveric shoulder specimens with a mean age of 57 years (range: 54-61 years) were randomized to receive a knotless double-row repair with either a 3AS or 2HB construct. In the 3AS construct, three 2.6-mm all-suture anchors were placed adjacent to the articular margin and secured laterally with two 4.75-mm knotless hard body anchors. In the 2HB construct, two 4.75-mm medial hard body anchors were placed medially, lateral fixation was identical to the 3AS construct. Creep, displacement, stiffness, and ultimate load were recorded for each sample. In addition, a SynDaver model was used to compare contact pressure between the 2 repair constructs.

Results

There were no differences in cyclic displacement at 1, 30, and 100 cycles (P = .616, .497, .190, respectively), cyclic stiffness (.928), ultimate load (.445), or load to failure (P = .445) between the 2 constructs. The 3AS repair construct had improved contact pressure between tendon and bone when compared with the 2HB construct at loads of 20 N, 30 N, and 40 N (P = .01, .02, and .04, respectively).

Conclusions

Displacement and load to failure properties are similar between knotless constructs using either 2HB or 3AS for the medial row. However, contact force may improve with the use of 3 medial all-suture anchors.

Clinical Relevance

As all-suture anchors are smaller in size when compared with hard body anchors. For this reason, there is potential to place an additional all-suture medial anchor to improve contact force and potentially improve rotator cuff healing when compared with the use of hard body anchors.