Humeral stem alignment of curved short stem in reverse shoulder arthroplasty: Varus/Valgus alignment is not a determinant for clinical outcomes.

BACKGROUND: This study aimed to investigate the influence of curved short stem alignment within the proximal humerus on the clinical outcomes of reverse shoulder arthroplasty. We hypothesized that the varus/valgus alignment would yield clinical outcomes comparable to those of a neutral alignment. METHODS: We retrospectively reviewed 167 patients who underwent reverse shoulder arthroplasty using the Aequalis Ascend Flex implant between January 2017 and December 2021. The study categorized the patients into three groups based on the angle difference between the humeral axis and the stem axis: neutral group (GN, defined as within ±5 degrees), valgus group (GL), and varus group (GR). Functional outcomes were assessed using the visual analog scale pain score, subjective shoulder value, American Shoulder and Elbow Surgeons score, University of California Los Angeles shoulder score, and active range of motion. Routine radiographic evaluations were also conducted to assess the filling ratio and bone resorption. RESULTS: Among 138 patients, 89 were in the GN group, 37 (27%) in the GL group, and 12 (9%) in the GR group. The average degree of varus alignment was 6 (range from 5 to 7 degrees), while the average degree of valgus alignment was -7 (range from -8 to -5 degrees). According to our findings, the clinical outcomes did not exhibit significant differences between the three groups. Furthermore, the radiological outcomes showed no significant differences among the three groups. CONCLUSIONS: Compared to neutral alignment, varus or valgus alignment of the humeral stem in reverse shoulder arthroplasty using a curved short stem does not significantly affect clinical outcomes.

Lateral Wall Integrity of the Greater Tuberosity Is Important for the Stability of Osteoporotic Proximal Humeral Fractures After Plate Fixation.

BACKGROUND: Previous studies assessing surgical fixation of osteoporotic proximal humeral fractures have primarily focused on medial calcar support. In this study, we utilized a specific model for 2-part surgical neck fracture of the osteoporotic proximal humerus to investigate how severe comminution of the greater tuberosity (GT) lateral wall affects biomechanical stability after fixation with a plate. METHODS: Ten matched pairs of cadaveric humeri (right and left) were assigned to either a surgical neck fracture alone (the SN group) or a surgical neck fracture with GT lateral wall comminution (the LW group) with use of block randomization. We removed 5 mm of the lateral wall of the GT to simulate severe comminution of the lateral wall. Axial compression stiffness, torsional stiffness, varus bending stiffness, and the single load to failure in varus bending were measured for all plate-bone constructs. RESULTS: Compared with the SN group, the LW group showed a significant decrease in all measures, including torsional stiffness (internal, p = 0.007; external, p = 0.007), axial compression stiffness (p = 0.002), and varus bending stiffness (p = 0.007). In addition, the mean single load to failure in varus bending for the LW group was 62% lower than that for the SN group (p = 0.005). CONCLUSIONS: Severe comminution of the GT lateral wall significantly compromised the biomechanical stability of osteoporotic, comminuted humeral surgical neck fractures. CLINICAL RELEVANCE: Although the generalizability of this cadaveric model may be limited to the extreme clinical scenario, the model showed that severe comminution of the GT lateral wall significantly compromised the stability of osteoporotic humeral surgical neck fractures fixed with a plate and screws alone.

Optimal immobilization position for conservative treatment of proximal humerus fractures by fracture type: a biomechanical cadaveric study.

In conservative treatment for proximal humerus fractures (PHFs), the immobilization position of the affected arm should not be determined uniformly. The aim of this study is to investigate the optimal immobilization position for conservative treatment of different types of PHFs. We hypothesized that the optimal position minimizing the deforming force in PHFs depends on the fracture components involved. PHF models involving either the surgical neck (SN) or greater tuberosity (GT) were created using 12 fresh-frozen cadaveric shoulders. In the SN model, the deforming forces on the pectoralis major muscle were measured in full adduction by increasing external rotation. In the GT model, the deforming force of the supraspinatus muscle was measured in neutral rotation by decreasing abduction, and the deforming force of the infraspinatus muscle was measured in full adduction by increasing internal rotation, respectively. In the SN model, the deforming force of the pectoralis major muscle increased significantly with external rotation from full internal rotation to neutral rotation (P = 0.006), indicating that the arm should be placed in full internal rotation. In the GT model, the deforming force of the supraspinatus muscle increased significantly with adduction from 45° of abduction to full adduction (P = 0.006); the deforming force of the infraspinatus muscle increased significantly with internal rotation from neutral rotation to full internal rotation (P = 0.006). These findings should be considered when placing the arm in abduction and neutral rotation so as to minimize the deforming force by either the supra or infraspinatus muscle. In conservative treatment for PHFs, the affected arm should be placed in a position that minimizes the deforming force on the fracture components involved.

Heated Tobacco Products Have Detrimental Effects on Rotator Cuff Healing, Similar to Conventional Cigarettes.

BACKGROUND: Cigarette smoking impairs rotator cuff healing, but no study, to our knowledge, has focused on the association between heated tobacco products and rotator cuff tears. METHODS: This study retrospectively investigated 1,133 patients who underwent arthroscopic repair of symptomatic rotator cuff tears between March 2011 and April 2021. Patients were grouped on the basis of their smoking patterns as nonsmokers, cigarette smokers, and heated tobacco smokers. Propensity score matching was used to reduce selection bias, and 45 subjects were selected from each group via 1:1:1 matching. Functional scores and active range of motion were compared among the 3 groups preoperatively and at a 2-year follow-up. Postoperative magnetic resonance imaging was performed 6 months after the surgical procedure to assess structural integrity. RESULTS: Except for sex, similar baseline characteristics were achieved after propensity score matching. There were no differences in the clinical scores or range of motion between the matched groups either preoperatively or at the 2-year follow-up. However, the retear rate for the matched nonsmoker group was significantly lower (8.9%) than those for the matched cigarette smoker group (31.1%) and the heated tobacco smoker group (28.9%) (p = 0.022). Multivariable logistic regression analysis revealed that the retear rates were 3.403 times higher for the cigarette smoker group and 3.397 times higher for the heated tobacco smoker group than that for the nonsmoker group. CONCLUSIONS: Heated tobacco users, like conventional cigarette smokers, have worse clinical outcomes with respect to rotator cuff healing than nonsmokers. Regardless of the type of cigarette, abstinence from smoking is necessary for patients undergoing rotator cuff repair surgery. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Comparing the Biomechanical Stability of Cerclage Cable with Plate Insert Versus Locking Screw in Periprosthetic Humeral Fracture.

BACKGROUND: In the setting of periprosthetic humeral fractures, the humeral stem of the implant represents a substantial challenge to the optimal method of proximal fixation. This study aimed to compare the initial biomechanical stability provided by cerclage cables with a locking plate insert versus bicortical locking screws (i.e., the gold standard for fixation) in fresh cadaveric humeri. METHODS: After calculating the sample size, we utilized 10 sets of cadaveric specimens and created a 5-mm osteotomy gap 120 mm distal to the tip of the greater tuberosity, simulating a Wright and Cofield type-B periprosthetic humeral fracture on each specimen. Using 3 locking screws for distal fragment fixation, identical in all specimens, the specimens were assigned to Group A (3 cerclage cables with a plate insert) or Group B (3 locking bicortical screws) for proximal fragment fixation. Biomechanical tests included stiffness in varus and valgus bending, torsion, and axial compression, and a single load to failure. RESULTS: No significant differences were observed in the biomechanical metrics between the 2 groups. CONCLUSIONS: Our study revealed that fixation with use of cerclage cables with a plate insert demonstrated biomechanical stability comparable with that of bicortical locking screw fixation when addressing the proximal fragment in Wright and Cofield type-B periprosthetic humeral fractures. CLINICAL RELEVANCE: For proximal fragment fixation of periprosthetic humeral fractures, cerclage cables with a plate insert can be utilized as an effective fixation method that offers initial fixation strength that is comparable to the use of 3 locking bicortical screws.

The Treatment of Periprosthetic Fracture Revision of the Humerus with "Bamboo Support" Structural Allograft Technique-Atrophic Non-Union of a Post-Operative Periprosthetic Fracture after Reverse Total Shoulder Arthroplasty: A Case Report.

Periprosthetic fractures are a serious complication of joint replacement surgery. With the growing prevalence of reverse total shoulder arthroplasty (RTSA), the incidence of relatively uncommon periprosthetic humeral fractures has increased. Here, we present the unique case of a 74-year-old woman who developed atrophic non-union after plate osteosynthesis for a periprosthetic fracture associated with RTSA. Fixation failure was evident 3 months after the surgical intervention; the patient underwent a 3-month course of arm sling immobilization. However, bone resorption continued, and varus angulation of the fracture developed. In this case, surgical strategy involved the use of long proximal humerus internal locked system plate (DePuy Synthes, Paoli, PA, USA), augmented with autologous iliac bone graft and allogenic humerus structural bone graft with the "bamboo support technique", fixed with Cable System (DePuy Synthes, Paoli, PA, USA). No reports have addressed the management of failed periprosthetic fractures using allogeneic humeral strut bone grafts. This report aims to fill the gap by presenting a novel surgical technique for the management of periprosthetic fractures associated with RTSA in case of treatment failure.

Congruent Concavity Restoration of the Reconstructed Glenoid After the Latarjet Procedure: Compensation for the Position of the Graft.

BACKGROUND: Few clinical studies have addressed concavity restoration by natural remodeling after a Latarjet procedure. This study investigated the fibrous tissue and osseous remodeling of the reconstructed glenoid and concavity restoration after a Latarjet procedure using postoperative computed tomographic arthrography (CTA). METHODS: This retrospective study included 31 patients who underwent immediate postoperative computed tomographic (CT) scanning followed by CTA at 6 months postoperatively. We investigated whether fibrous tissue was newly created over the graft, whether the created fibrous tissue restored the congruity of the articular surface and the osseous remodeling of the graft to the glenoid level (whether the osseous portion of the graft was remodeled flush to the glenoid level) and the concavity of the glenoid using the radius of a best-fit circle on the articular surface, and the relationship between the amount of created fibrous tissue and the position of the graft. RESULTS: In all patients, the fibrous tissue on the graft yielded a smooth articular surface, as revealed by the CTA. The mean radius of the entire glenoid, including the transferred graft, was significantly smaller (p = 0.010) at 33.2 ± 8.5 mm than that of the glenoid posterior to the osseous step-off at 37.6 ± 9.4 mm, which is presumed to be the glenoid before the surgical procedure. Despite the congruity of the articular surfaces due to fibrous tissue seen in the CTA, 14 (45%) of 31 patients showed a subchondral osseous step-off on either the medial side or the lateral side in the immediate postoperative CT scans. However, through osseous remodeling, 8 of the 10 grafts with a lateral step-off and 2 of the 4 grafts with a medial step-off converted to a flush position. The position of the step-off was correlated with the thickness of the fibrous tissue, with a tendency for thicker tissue in cases of a step-off on the medial side (p = 0.014). CONCLUSIONS: Fibrous tissue formation plus remodeling of the transferred graft resulted in the restoration of a congruent concavity after a Latarjet procedure by compensating for initially non-flush positioning of the graft. However, due to the small sample size in our study, clinical outcomes could not be correlated with radiographic findings, and our recommendation is to continue placing the graft as anatomically as possible. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Effect of cigarette smoking on the maintenance of reduction after treatment of acute acromioclavicular joint dislocation with hook plate fixation.

BACKGROUND: The purpose of this study was to determine the association between smoking and clinical outcomes of hook plate fixation for acute acromioclavicular (AC) joint injuries. METHODS: This study retrospectively investigated 82 patients who underwent hook plate fixation for acute AC joint dislocation between March 2014 to June 2022. The patients were grouped by smoking status, with 49 in group N (nonsmokers) and 33 in group S (smokers). Functional scores and active range of motion were compared among the groups at the 1-year follow-up. Coracoclavicular distance (CCD) was measured, and difference with the uninjured side was compared at initial injury and 6 months after implant removal. RESULTS: No significant differences were observed between the two groups in demographic factors such as age and sex, as well as parameters related to initial injury status, which included time from injury to surgery, the preoperative CCD difference value, and the Rockwood classification. However, the postoperative CCD difference was significantly higher in group S (3.1±2.6 mm) compared to group N (1.7±2.4 mm). Multivariate regression analysis indicated that smoking and the preoperative CCD difference independently contributed to an increase in the postoperative CCD difference. Despite the radiographic differences, the postoperative clinical outcome scores and active range of motion measurements were comparable between the groups. CONCLUSIONS: Smoking had a detrimental impact on ligament healing after hook plate fixation for acute AC joint dislocations. This finding emphasizes the importance of smoking cessation to optimize reduction maintenance after AC joint injury. Level of evidence: III.

Comparison of the Goutallier Classification of Fatty Infiltration for the Subscapularis With a Novel Modified Classification.

Background: Fatty infiltration in the subscapularis muscle extends to the upper portion of the muscle first and then to the lower portion only after some degree of fatty change has taken place in the upper region. Although the Goutallier classification is the most widely used method to categorize fatty infiltration, how to accurately and reliably determine the extent of infiltration is controversial. Purpose: To examine a modified classification that is more reliable in (1) assessing fatty infiltration of the subscapularis muscle and (2) predicting the structural integrity of the repaired tendon by identifying cutoff points for retear. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: This study retrospectively examined the records of 545 patients who underwent arthroscopic repair for a subscapularis tear. Two shoulder surgeons reviewed the preoperative magnetic resonance imaging scans of all enrolled patients and evaluated the fatty infiltration of the subscapularis muscle based on the original Goutallier classification, as well as a novel modified Goutallier classification designed to measure the proportion of fat and muscle in the upper and lower portions of the muscle separately. Intra- and interobserver agreement of the reviewers was calculated using κ statistics. Using receiver operating characteristic curve analysis, we determined the cutoff point for the particular fatty infiltration grade related to the occurrence of retear for each classification scheme. Results: The κ values for interobserver reliability were 0.743 and 0.856 for the original and modified Goutallier classifications, respectively, with the modified classification having significantly higher reliability (Z = 4.064; P < .001). Cutoff points for the fatty infiltration grade associated with retear were 2.5 for the original Goutallier classification (sensitivity, 65.3%; specificity, 95.6%; accuracy, 87.8%) and 3.5 for the modified classification (sensitivity, 52.5%; specificity, 97.8%; accuracy, 89.7%). Conclusion: In assessing fatty infiltration of the subscapularis muscle, the modified Goutallier classification showed higher reliability than the original Goutallier classification. The cutoff point for potential retear (grade 3.5) was at a point where the fatty infiltration extended to the lower portion of the subscapularis muscle.

The biomechanical effect of fibular strut grafts on humeral surgical neck fractures with lateral wall comminution.

No studies have evaluated the effect of fibular strut augmentation on the stability of locking plate fixation for osteoporotic proximal humeral fractures with lateral wall comminution. The purpose of this study was to evaluate the stability of locking plate fixation with a fibular strut graft compared with locking plate alone in an osteoporotic two-part surgical neck fracture model with lateral cortex comminution. Ten paired fresh-frozen cadaveric humeri were randomly allocated into two groups, either the locking plate alone (LP group) or locking plate with fibular strut graft augmentation (LPFSG group), with an equal number of right and left osteoporotic surgical neck fractures with lateral wall comminution of the greater tuberosity. Varus, internal/external torsion, and axial compression stiffness as well as single load to failure were measured in plate-bone constructs, and the LPFSG group showed significantly greater values in all metrics. In conclusion, this biomechanical study shows that fibular strut augmentation significantly enhances varus stiffness, internal torsion stiffness, external torsion stiffness, and maximum failure load of a construct compared to locking plate fixation alone in proximal humeral fractures with lateral wall comminution.

Disagreement Between the Accepted Best-Fit Circle Method to Calculate Bone Loss Between Injured and Uninjured Shoulders.

BACKGROUND: No study has evaluated whether best-fit circles based on glenoids with defects accurately represent normal inferior glenoids before injury. PURPOSE: To investigate whether the best-fit circles on the affected side with a glenoid defect can accurately represent native glenoids before injury. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: This retrospective study included 58 patients with unilateral recurrent anterior shoulder instability. First, we compared the diameter of best-fit circles based on affected and unaffected glenoids. Glenoid defect sizes based on each best-fit circle were then calculated and compared. Second, we created serial virtual glenoid defects (10%, 15%, 20%, 25%) on unaffected glenoids and compared diameters of best-fit circles on the glenoids before and after virtual defects. We also analyzed and compared the size of virtual and calculated glenoid defects. Bland-Altman plots and intraclass coefficients (ICCs) were used to compare and analyze agreement of measurements. After categorization of glenoid defects based on clinical cutoff values, Cohen κ and percentage agreement were calculated. RESULTS: The diameter of 55.2% (32/58) of best-fit circles from affected glenoids over- or underestimated the diameter on the unaffected side by >5%. In 28 of the 32 patients, the diameter of the affected side circle was overestimated. Consequently, 41.4% (24/58) of glenoid defects were over- or underestimated by >5%. In 19 of the 24 patients, the glenoid defect from the affected side was >5% larger. ICCs between sides for best-fit circle diameters and defect sizes were 0.632 and 0.800, respectively. Agreement of glenoid defect size between sides was 58.6% (34/58) overall, but when the defect was ≥10%, agreement decreased to 32.3% (10/31). Among 232 glenoids with virtual defects created from 58 normal glenoids, the diameter of 31.0% (72/232) of best-fit circles and the size of 11.6% (27/232) of defects were over- or underestimated by >5%. CONCLUSION: When assessing glenoid defects in anterior shoulder instability, best-fit circles based on affected glenoids do not always represent the native glenoid and may thus lead to inaccurate circle sizes and defect estimates.

Age, Tear Size, Extent of Retraction, and Fatty Infiltration Associated With a High Chance of a Similar Rotator Cuff Tear in the Contralateral Shoulder Regardless of Symptoms in Patients Undergoing Cuff Repair in the Index Shoulder.

PURPOSE: To investigate the prevalence of a contralateral rotator cuff tear (RCT) in patients with a symptomatic RCT requiring repair and to determine whether findings from magnetic resonance imaging (MRI) of the affected shoulder can predict the presence of a contralateral tear. METHODS: Patients with atraumatic RCTs who had undergone arthroscopic repair between March 2019 and February 2021 were reviewed in this study. MRI of both shoulder joints was performed to evaluate the bilaterality of RCT. Demographic factors and MRI findings of index shoulders were assessed using logistic regression analysis to reveal any correlations with the presence of RCT in the contralateral shoulder. RESULTS: A total of 428 patients were enrolled in this study. When the affected shoulders had a posterosuperior rotator cuff (PSRC) or subscapularis tear including either an isolated or combined tear, 63.6% and 67.8% had the same tears on the contralateral side, respectively. A contralateral-side tear was found in 74.6% (185/248) of symptomatic cases and 44.8% (65/145) of asymptomatic cases, which represents a significant difference (P < .001). Logistic regression analysis revealed that age ≥67.5 years, tear size ≥17 mm, Goutallier grade ≥1.5, and Patte grade ≥1.5 were found to be indicative of potential contralateral PSRC tears. By contrast, the presence of a subscapularis tear in the affected shoulder was the only significant risk factor in predicting a potential subscapularis tear in the contralateral shoulder. CONCLUSIONS: Among patients with a symptomatic RCT requiring arthroscopic repair, 63.6% with a PSRC tear and 67.8% with a subscapularis tear in the affected shoulder were found to have a similar tear in the contralateral shoulder regardless of symptoms. Age, tear size, extent of retraction, fatty infiltration of PSRC tears, and the presence of subscapularis tears were identified as factors predictive of tears on the contralateral side. LEVEL OF EVIDENCE: Level IV, case series.

Subscapularis tendon tears hidden by the medial biceps sling can be missed on arthroscopic examination.

INTRODUCTION: To investigate (1) the prevalence of "hidden lesions" and "non-hidden lesions" of subscapularis tendon tears requiring repair during arthroscopic examination that would be missed by a 30° arthroscope, but could be identified by a 70° arthroscope, from the standard posterior portal and (2) the correlation of preoperative internal rotation weakness and findings of magnetic resonance imaging (MRI) indicating hidden lesions. MATERIALS AND METHODS: We retrospectively examined 430 patients who underwent arthroscopic subscapularis repair between was initially nonvisible with a 30° arthroscope but became visible only with a 70° arthroscope from the standard posterior portal. The preoperative and intraoperative findings of the hidden lesion group (n = 82) were compared with those of the non-hidden lesion group (n = 348). 2016 and 2020. A hidden lesion was defined as a subscapularis tendon tear requiring repair that preoperative internal rotation weakness was assessed using the modified belly-press test. Preoperative MR images were reviewed using a systemic approach. RESULTS: The prevalence of hidden lesions was 19.1% (82/430). No significant difference was found in preoperative internal rotation weakness between the groups. Preoperative MRI showed a significantly lower detection rate in the hidden lesion group than in the non-hidden group (69.5% vs. 84.8%; P = 0.001). The hidden lesions were at a significantly earlier stage of subscapularis tendon tears than the non-hidden lesions, as revealed by the arthroscopic findings (Lafosse classification, degree of retraction; P = 0.003 for both) and MR findings (muscle atrophy, fatty infiltration; P = 0.001, P = 0.005, respectively). CONCLUSIONS: Among the subscapularis tears requiring repair, 19.1% could be identified by a 70° arthroscope, but not by a 30° arthroscope, through the posterior portal. The hidden lesions showed a significantly lower detection rate on preoperative MRI than the non-hidden lesions. Thus, for subscapularis tears suspected on preoperative physical examination, the 70° arthroscope would be helpful to avoid a misdiagnosis.

Comparison of arthroscopic primary and revision Bankart repair for capsulolabral restoration: a matched-pair analysis.

INTRODUCTION: There have been no previous studies comparing serial radiologic results between primary and revision Bankart repair despite the significance of capsulolabral height and slope restoration. The purpose of this study was (1) to compare serially the height and slope of the repaired labrum in the early postoperative period among primary and revision Bankart repair groups, and (2) to compare clinical outcomes between the two groups. MATERIALS AND METHODS: This study included each 24 patients who underwent arthroscopic primary Bankart repair (Group A) and revision Bankart repair (Group B) matched by age, sex, and glenoid defect ratio. Postoperative serial radiologic assessment of the repaired labral height and slope was proceeded using magnetic resonance imaging (MRI) or computed tomographic arthrography (CTA) at 3 weeks and 6 months. RESULTS: There were no significant differences in labral height and slope at 3 weeks and 6 months postoperatively in Group A. However, significant reductions in labral height and slope were evident between 3 weeks and 6 months postoperatively in Group B (P < 0.05). Group A yielded superior results to Group B with respect to labral height and slope at each time point (P < 0.05) in between-group analyses. The clinical outcomes were not significantly different between the two groups except for the patients' return to their premorbid sports activity level (P = 0.024). CONCLUSIONS: The height and slope of the repaired capsulolabral structures in the early postoperative period after arthroscopic revision Bankart repair group were significantly lower than those of the primary Bankart repair group. Also the reduction of labral height and slope was significant in the revision Bankart repair group over time. Nonetheless, clinical outcomes did not differ significantly except return to premorbid sports activity level at final follow-up.

High failure rate after conservative treatment for recurrent shoulder dislocation without subjective apprehension on physical examination.

PURPOSE: The purpose of this study was to investigate the outcomes of conservative treatment for recurrent shoulder dislocation without subjective apprehension, despite the presence of a Bankart lesion or glenoid defect. METHODS: A retrospective analysis was performed for 92 patients with recurrent shoulder dislocation treated with conservative treatment due to negative apprehension between 2009 and 2018. The failure of the conservative treatment was defined as a dislocation or subluxation episode or subjective feeling of instability based on a positive apprehension. The Kaplan-Meier method was used to estimate failure rates over time, and a receiver operating characteristic (ROC) curve was constructed to determine a cut-off value for a glenoid defect. The clinical outcomes were compared between patients who completed conservative treatment without recurrence of instability (Group A) and those who failed and subsequently underwent surgical treatment (Group B) using shoulder functional scores and sports/recreation activity level. RESULTS: This retrospective study included 61 of 92 eligible patients with recurrent shoulder dislocation. Among the 61 patients, conservative treatment failed in 46 (75.4%) over the 2-year study period. The cut-off value for a glenoid defect was 14.4%. The association between glenoid defect size (≥ 14.4% or as a continuous variable) and survival was statistically significant (p = 0.039 and p < 0.001, respectively). The mean glenoid defect size in Group B increased from 14.6 ± 3.0% to 17.3 ± 3.1% (p < 0.001), and clinical outcomes for Group A were inferior to those for Group B at the 24-month follow-up. CONCLUSIONS: Conservative treatment for recurrent shoulder dislocation in patients without subjective apprehension showed a high failure rate during the study period, especially if the glenoid defect was ≥ 14.4% in size. Despite clinical improvement in patients who completed conservative treatment without recurrence, functional outcome scores and sport/recreation activity levels were better in the patients who underwent arthroscopic Bankart repair. Therefore, for recurrent anterior shoulder instability, even without subjective apprehension, surgical treatment is warranted over conservative treatment. LEVEL OF EVIDENCE: Level IV.

Pull-out Strength of Suture Anchor and Torque of Buddy Anchor for an Osteoporotic Humeral Head in Rotator Cuff Repair: Parallel Versus Divergent Insertion.

BACKGROUND: The buddy anchor technique is useful to reinforce loose anchors in the osteoporotic humeral head during arthroscopic rotator cuff repair. However, theoretical parallel insertion of the buddy anchor to index a loose anchor is challenging in arthroscopy and can widen the entry site and decrease structural integrity. PURPOSE: To investigate and compare the biomechanical stability between 2 buddy anchor insertion techniques (parallel insertion vs divergent insertion) in the osteoporotic humeral head. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 24 paired fresh-frozen cadaveric shoulders were used, and each pair was randomly assigned to either the parallel insertion group or the divergent insertion group. In the parallel insertion group, the buddy anchor was inserted parallel to the index loose anchor. In the divergent insertion group, the buddy anchor was inserted at a 20° angle in the medial direction to the index loose anchor. The insertion torque of the buddy anchor and ultimate pull-out strength of the index anchor were measured and compared between the 2 groups. RESULTS: The mean maximum insertion torque was significantly higher in the parallel insertion group (16.1 ± 1.8 cN·m) compared with the divergent insertion group (12.0 ± 1.5 cN·m) (P < .001). The mean ultimate pull-out strength was significantly higher with divergent insertion (192.2 ± 28.6 N) than with parallel insertion (147.7 ± 23.6 N) (P < .001). CONCLUSION: For application of the buddy anchor system in the cadaveric osteoporotic humeral bone model, divergent insertion showed better ultimate pull-out strength than conventional parallel insertion, despite inferior maximum insertion torque. CLINICAL RELEVANCE: The results of this study widen the applicability and accessibility for the buddy anchor system.

Relation between diameter of a lateral screw and pull-out strength in distal clavicle fracture in plates with different geometry: A cadaveric biomechanical study.

Plate fixation has recently gained popularity among the various surgical methods used to treat Neer type II distal clavicle fractures. The use of a low-profile distal clavicle locking plate is logically considered a better option when there is no significant difference in the fixation strength between insertions of 3.5- and 2.7-mm diameter screws. Therefore, the purpose of this biomechanical study was to investigate any differences in fixation strength among varying sizes of screws that are used to treat distal clavicle fractures. The study was performed with 20 paired shoulder girdles from 10 fresh frozen cadavers. To create a type IIA fracture of Neer classification, osteotomy was performed perpendicularly to the longitudinal axis of the clavicle at the medial end point of the conoid ligament. Two custom-made fixtures designed to be attached to both upper and lower sides of the Instron were fabricated for the evaluation. The mean maximum pull-out strength for fixation using 3.5-mm diameter screws was 241.9 ± 67.8 N, whereas the mean pull-out strength in fixation with 2.7-mm diameter screws was 228.1 ± 63.0 N. There was no statistically significant difference between the two groups. Distal fragment fixation with distal clavicle locking plates using two 2.7-mm diameter screws showed comparable biomechanical pull-out strength at the time-zero setting to fixations with a hook plate using two 3.5-mm diameter screws. Therefore, the fixation of the distal fragment with a low-profile plate and 2.7-mm screws may be preferred as an alternative option if the distal fragment of the fractured clavicle is not extremely small.

Arthroscopic Revision Rotator Cuff Repair: The Role of Previously Neglected Subscapularis Tears.

BACKGROUND: Concomitant full-thickness tear of the subscapularis tendon is often neglected during primary posterosuperior rotator cuff repair, and its significance has not been investigated by any previous clinical study. PURPOSE: To investigate (1) the clinical and radiological outcomes of revision arthroscopic rotator cuff repair and (2) the number of neglected concomitant subscapularis full-thickness tears in the revision of posterosuperior rotator cuff retears and their structural integrity after repair. STUDY DESIGN: Case series, Level of evidence, 4. METHODS: This study retrospectively examined 58 patients who underwent arthroscopic rotator cuff revision for a retear of a previously repaired posterosuperior rotator cuff. Preoperative and postoperative functional scores and active range of motion (ROM) were assessed. The initial and most recent follow-up magnetic resonance imaging scans before revision and arthroscopic findings at the time of primary repair were reviewed to determine whether the concomitant subscapularis tear was newly developed or preexisting. Final confirmation of the tendon's full-thickness tear was made during the revision procedure. RESULTS: At final follow-up, mean functional shoulder scores and ROM improved significantly compared with the preoperative values (P < .001). Among the 58 revision cases, 25 (43.1%) had a neglected full-thickness tear of the subscapularis tendon. The fatty infiltration grade of the neglected subscapularis tear progressed from a mean of 1.1 before primary repair to a mean of 1.6 before revision, and the change indicated statistically significant deterioration (P < .001). Despite clinical improvement after revision surgery, the retear rate was considerable in the re-repaired cuff tendons (37.9%) as well as for the repaired concomitant subscapularis tears (24%). CONCLUSION: Among revision rotator cuff repairs, 43.1% had neglected subscapularis tears, and fatty infiltration of these initially neglected subscapularis tendons showed further progression at the time of revision. The retear rate after the repair of neglected subscapularis tears was higher than expected. Thus, detecting and treating subscapularis tear via meticulous preoperative evaluation and thorough inspection during primary arthroscopy are essential.

Association Between Excessive Joint Laxity and a Wider Hill-Sachs Lesion in Anterior Shoulder Instability.

BACKGROUND: Excessive general joint laxity, a negative prognostic factor in joint instability, has not been studied to determine its relationship with bipolar bone loss in anterior shoulder instability. PURPOSE/HYPOTHESIS: This study aimed to investigate the characteristics of bipolar bone defects in the presence of excessive joint laxity and the clinical outcomes based on the on-track/off-track theory. We hypothesized that (1) patients with excessive joint laxity might have less significant bipolar bone defects compared with those without excessive joint laxity and (2) no significant difference would be found in the clinical outcomes, including recurrence rate. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This study included 81 patients who had undergone arthroscopic Bankart repair, with (group L; n = 33) or without (group N; n = 48) excessive joint laxity. The presence of excessive joint laxity was defined as a score of ≥4 using Beighton and Horan criteria preoperatively. Bipolar bone lesions were assessed using preoperative 3-dimensional computed tomography. Additional remplissage was performed for cases with off-track or positive engagement test in borderline on-track lesions. The functional outcomes at the 2-year follow-up were assessed using the recurrence rate, Subjective Shoulder Value, Rowe score, University of California Los Angeles shoulder score, active range of motion, and the sports/recreation activity level. RESULTS: No significant difference was found in the glenoid bone defect between groups (14.1%, group L; 14.4%, group N). Off-track lesions were identified in 39.4% (13/33) of group L and 14.6% (7/48) of group N (P = .011). The mean Hill-Sachs interval to glenoid track ratio was 83.1% in group L and 75.2% in group N (P = .021). Additional remplissage procedures were more frequently performed in group L (48.5%; 16/33) than in group N (16.7%; 8/48) (P = .002). However, no significant difference was observed in the shoulder functional scores and recurrence rates between the groups. CONCLUSION: Patients with anterior shoulder instability and excessive joint laxity had significantly wider Hill-Sachs lesions and more off-track lesions than did those with normal joint laxity despite the lack of a significant difference in the glenoid bone defect. However, these differences in the Hill-Sachs lesion were not related to differences in the functional outcomes between the groups.