Determining patient acceptable symptom states from patient reported outcome measures following reverse shoulder arthroplasty: Constant-murley, UCLA, Oxford Shoulder Scores.

Aims: To establish cut-off values for Patient-Acceptable Symptom States (PASS) in three Patient Reported Outcome Measures (PROMs), the Constant-Murley Score (CMS) and University of California Los Angeles (UCLA) Shoulder Score and Oxford Shoulder Score (OSS) at 3, 6, and 12-months following reverse shoulder arthroplasty (RSA). Methods: A retrospective study was conducted for individuals who were treated for massive rotator cuff tear, rotator cuff arthropathy or proximal humerus fractures with RSA from January 2011 and February 2020. This study included patients who have completed the patient reported outcome measures (PROMs) and satisfaction questions preoperatively, and at 3, 6 and 12-months after the procedure. Functional outcome were evaluated by CMS, UCLA shoulder score and OSS, with one anchoring question regarding satisfaction. PASS thresholds for each PROM were obtained with the Youden method, by using the receiver operating characteristic analysis, and secondary analysis was performed with the 80% specificity and 75th percentile method. Results: 129 patients were included. 74.2%, 83.9%, and 89.3% of patients were found to have a satisfactory symptom state at 3, 6 and 12-months postoperatively. At 3, 6 and 12-month intervals, the respective PASS thresholds were 42, 39 and 52 for CMS, 17, 21 and 26 for UCLA score and 28, 25 and 18 for OSS. Conclusions: PASS thresholds for RSA at 3, 6 and 12-months were found for CMS (42, 39, 52), UCLA (17, 21, 26) and OSS (28, 25, 18). These thresholds suggest increasing expectations with a trend towards higher functional requirements at each time point.

Abduction causes increased strain gradient compared to forward flexion: Evidence from a cadaver model of simultaneous strain study of the rotator cuff tendons.

BACKGROUND: Various strain studies of the supraspinatus have been done in isolation. Given that rotator cuff muscles function as a group, it may be physiologically representative to measure strain behaviour with the glenohumeral joint intact. Here, we explored a novel method in measuring simultaneous strain behaviour of the rotator cuff tendons and investigated the effect of full-thickness anterior tear of the supraspinatus on the infraspinatus and subscapularis tendons. METHODS: Nine cadaveric shoulders were evaluated on a customized rig. Using linear differential variable transducers to measure strain, each shoulder was subjected to up to 60° of elevation in the coronal, scapular, and sagittal planes. We also assessed 30° of external rotation and up to 60° of internal rotation of the humerus. Full-thickness anterior tear of the supraspinatus was then made before re-assessing strain patterns in the scapular plane. FINDINGS: Strain measurements of the intact tendons revealed a significant strain gradient between the articular and bursal sides of the supraspinatus during increasing degrees of elevation in the coronal and scapular planes. Full thickness anterior tear of the supraspinatus is localised to the tendon and does not affect the surrounding cuff musculature, with a potential shielding effect of the infraspinatus during early glenohumeral abduction. INTERPRETATION: Significant strain gradient exists between the articular and bursal sides of the supraspinatus during abduction but not during forward flexion in an intact glenohumeral joint. Rehabilitation exercises for anterior supraspinatus tears can be appropriately targeted on the remaining intact rotator cuff musculature.

Rotator cuff repair with an interposition polypropylene mesh: A biomechanical ovine study.

BACKGROUND: Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair. We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs. We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair. AIM: To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model. METHODS: A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear. We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair. In seven specimens, the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens. Five specimens with an intact tendon were tested. The specimens underwent cyclic loading to determine the ultimate failure load and gap formation. RESULTS: The mean gap formation after 3000 cycles was 1.67 mm in the continuous group, and 4.16 mm in the mattress group (P = 0.001). The mean ultimate failure load was significantly higher at 549.2 N in the continuous group, 426.4 N in the mattress group and 370 N in the intact group (P = 0.003). CONCLUSION: The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.

Minimal Clinically Important Differences for Oxford, Constant, and University of California Los Angeles Shoulder Scores After Reverse Shoulder Arthroplasty to Allow Interpretation of Patient-Reported Outcome Measures and Future Statistical Power Analyses.

PURPOSE: To determine the minimal clinically important difference (MCID) for the Constant-Murley Score (CMS), University of California Los Angeles (UCLA) Shoulder Score, and Oxford Shoulder Score (OSS) after reverse shoulder arthroplasty. METHODS: Patients were prospectively followed up between January 2011 and February 2020. Inclusion criteria was that of patients who underwent reverse shoulder arthroplasty for massive irreparable cuff tear, cuff tear arthropathy, and fractures, with and without previous cuff repair, by a fellowship-trained surgeon. Patients were assessed preoperatively and at 3, 6, and 12 months' postoperatively. Functional outcome was assessed by the CMS, UCLA Shoulder Score, and OSS and the respective MCIDs were determined using simple linear regression in consonance with patient satisfaction and expectation fulfilment. RESULTS: A total of 131 patients were followed up for 12 months. The MCIDs at 3 months for CMS, UCLA Shoulder Score, and OSS were 7.2, 3.3, and 6.9, respectively. At 6 months, the MCIDs for CMS, UCLA Shoulder Score, and OSS were 6.6, 2.4, and 4.7, respectively. At 12 months, the MCIDs for CMS, UCLA Shoulder Score, and OSS were 9.3, 2.9, and 6.6, respectively. CONCLUSIONS: CMS, UCLA Shoulder Score, and OSS are valid scores to calculate MCID after reverse shoulder arthroplasty, and the MCID established in this study can be used for the interpretation of these scores to help in statistical power analysis for future studies. LEVEL OF EVIDENCE: III, retrospective cohort study.

Diagnosis and treatment of avascular necrosis of the humeral head: Current concepts.

Avascular necrosis (AVN) of the humeral head is an uncommon clinical entity which can result in significant morbidity for patients. There is a paucity of literature concerning humeral head AVN, which may be due to the relatively rarity of the condition and poorly understood nature. Despite being first described decades ago, the underlying pathophysiology leading to humeral head AVN is still poorly defined. While the staging of humeral head AVN is well described, not much is known about prognosticating factors to predict the eventual course. Most of the management options are based on that of femoral head AVN, and even so, there is a paucity of good quality clinical trials in the literature. This current concepts paper describes what is known about humeral head AVN and proposes a management algorithm to guide clinicians.

Computer-assisted navigation in ACL reconstruction improves anatomic tunnel placement with similar clinical outcomes.

BACKGROUND: While the use of navigation systems in anterior cruciate ligament (ACL) reconstruction theoretically improves tunnel placement accuracy and clinical outcomes, the existing literature remains inconclusive. We aimed to evaluate the potential benefits of navigated ACL reconstruction on tunnel placement and clinical outcomes. METHODS: In this retrospective study, we evaluated a cohort of patients who underwent conventional or navigated (OrthoPilot system) primary ACL reconstruction at our institution from June 2004 to October 2009. Anteroposterior and lateral radiographic knee assessments were evaluated to assess postoperative tunnel positioning. Clinical outcomes, including the International Knee Documentation Committee classification, Lysholm score, and Tegner score, were evaluated preoperatively and 1-year postoperatively. Radiographic and clinical outcomes were compared and analysed using independent 2-sample t-tests and Chi-square tests. RESULTS: Sixty patients met the inclusion criteria and were included for analysis, comprising of 26 navigated and 34 conventional reconstructions. Postoperative radiographs showed no differences in tibial tunnel position between both groups, but a significantly smaller deviation from the recommended position in the navigated group (navigated: 5.96 %; conventional: 7.92 %; p = 0.008). Femoral tunnel placements in the navigated group were significantly more perpendicularly away from the Blumensaat line (navigated: 38.90 %; conventional: 31.94 %; p = 0.001), with a greater deviation from recommended position (navigated: 11.00 %; conventional: 6.94 %; p = 0.009). There were no differences in 1-year postoperative clinical outcomes (p > 0.05). CONCLUSION: Navigated ACL reconstruction resulted in a more anatomic femoral tunnel placement and similar clinical outcomes as conventional reconstruction. Further research should be conducted to clarify the potential biomechanical and clinical impacts of navigated ACL reconstruction.

Biomechanical comparison of vertical suture techniques for repairing radial meniscus tear.

PURPOSE: The aim of this study was to (1) develop suture techniques in repairing radial meniscal tear; (2) to compare the biomechanical properties of the proposed repair techniques with the conventional double horizontal technique. METHODS: Thirty-six fresh-frozen porcine medial menisci were randomly assigned into four groups and a complete tear was made at the midline of each meniscus. The menisci were subsequently repaired using four different repair techniques: double vertical (DV), double vertical cross (DVX), hybrid composing one vertical and one horizontal stitch, and conventional double horizontal (DH) suture technique with suturing parallel to the tibia plateau. The conventional double horizontal group was the control. The repaired menisci were subjected to cyclic loading followed by the load to failure testing. Gap formation and strength were measured, stiffness was calculated, and mode of failure was recorded. RESULTS: Group differences in gap formation were not statistically significant at 100 cycles (p = .42), 300 cycles (p = .68), and 500 cycles (p = .70). A trend was found toward higher load to failure in DVX (276.8 N, p < .001), DV (241.5 N, p < .001), and Hybrid (237.6 N, p < .001) compared with DH (148.5 N). Stiffness was also higher in DVX (60.7 N/mm, p < .001), DV (55.3 N/mm, p < .01), and Hybrid (52.1 N/mm, p < .01), than DH group (30.5 N/mm). Tissue failure was the only failure mode observed in all specimens. CONCLUSION: Our two proposed vertical suture techniques, as well as the double vertical technique, had superior biomechanical properties than the conventional technique as demonstrated by higher stiffness and higher strength.

Comparison of a simplified skin pointer device compared with a skeletal marker for knee rotation laxity: A cadaveric study using a rotation-meter.

AIM: To compare the measurements of knee rotation laxity by non-invasive skin pointer with a knee rotation jig in cadaveric knees against a skeletally mounted marker. METHODS: Six pairs of cadaveric legs were mounted on a knee rotation jig. One Kirscher wire was driven into the tibial tubercle as a bone marker and a skin pointer was attached. Rotational forces of 3, 6 and 9 nm applied at 0°, 30°, 45°, 60° and 90° of knee flexion were analysed using the Pearson correlation coefficient and paired t-test. RESULTS: Total rotation recorded with the skin pointer significantly correlated with the bone marker at 3 nm at 0° (skin pointer 23.9 ± 26.0° vs bone marker 16.3 ± 17.3°, r = 0.92; P = 0.0), 30° (41.7 ± 15.5° vs 33.1 ± 14.7°, r = 0.63; P = 0.037), 45° (49.0 ± 17.0° vs 40.3 ± 11.2°, r = 0.81; P = 0.002), 60° (45.7 ± 17.5° vs 34.7 ± 9.5°, r = 0.86; P = 0.001) and 90° (29.2 ± 10.9° vs 21.2 ± 6.8°, r = 0.69; P = 0.019) of knee flexion and 6 nm at 0° (51.1 ± 37.7° vs 38.6 ± 30.1°, r = 0.90; P = 0.0), 30° (64.6 ± 21.6° vs 54.3 ± 15.1°, r = 0.73; P = 0.011), 45° (67.7 ± 20.6° vs 55.5 ± 9.5°, r = 0.65; P = 0.029), 60° (62.9 ± 22.4° vs 45.8 ± 13.1°, r = 0.65; P = 0.031) and 90° (43.6 ± 17.6° vs 31.0 ± 6.3°, r = 0.62; P = 0.043) of knee flexion and at 9 nm at 0° (69.7 ± 40.0° vs 55.6 ± 30.6°, r = 0.86; P = 0.001) and 60° (74.5 ± 27.6° vs 57.1 ± 11.5°, r = 0.77; P = 0.006). No statistically significant correlation with 9 nm at 30° (79.2 ± 25.1° vs 66.9 ± 15.4°, r = 0.59; P = 0.055), 45° (80.7 ± 24.7° vs 65.5 ± 11.2°, r = 0.51; P = 0.11) and 90° (54.7 ± 21.1° vs 39.4 ± 8.2°, r = 0.55; P = 0.079). We recognize that 9 nm of torque may be not tolerated in vivo due to pain. Knee rotation was at its maximum at 45° of knee flexion and increased with increasing torque. CONCLUSION: The skin pointer and knee rotation jig can be a reliable and simple means of quantifying knee rotational laxity with future clinical application.

Arthroscopic undersurface rotator cuff repair versus conventional arthroscopic double-row rotator cuff repair - Comparable results at 2-year follow-up.

AIM: The aim of our study is to compare the improvement in clinical outcomes after conventional arthroscopic double-row rotator cuff repair and arthroscopic undersurface rotator cuff repair. METHOD: A consecutive series of 120 patients who underwent arthroscopic rotator cuff repair was analysed. Sixty-one patients underwent conventional double-row rotator cuff repair and 59 patients underwent undersurface rotator cuff repair. Several clinical outcomes, including numerical pain rating scale (NPRS), constant shoulder score (CSS), Oxford shoulder score (OSS) and University of California Los Angeles shoulder score (UCLASS), were prospectively recorded by a trained healthcare professional preoperatively and at 3, 6, 12 and 24 months after surgery. RESULT: Comparing both groups, there were no differences in age, gender and preoperative NPRS, CSS, OSS and UCLASS. However, the tear size was 0.7 ± 0.2 (95% confidence interval (CI) 0.3-1.1) cm larger in the conventional group ( p = 0.002). There was no difference in the improvement of NPRS, CSS, OSS and UCLASS at all time points of follow-up, that is, at 3, 6, 12 and 24 months after surgery. The duration of operation was shorter by 35 ± 3 (95% CI 28-42) min in the undersurface group ( p < 0.001). CONCLUSION: Both arthroscopic undersurface rotator cuff repair and conventional arthroscopic double-row rotator cuff repair showed marked improvements in clinical scores when compared preoperatively, and there was no difference in improvements between both groups. Arthroscopic undersurface rotator cuff repair is a faster technique compared to the conventional arthroscopic double-row rotator cuff repair.