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.

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.

Knee subchondroplasty for management of subchondral bone cysts: a novel treatment method

Knee subchondroplasty (SCP) is one of the most novel minimally invasive methods for treating bone marrow lesions. The literature suggests that it is safe, with few complications and good outcomes. However, no studies have documented its usage for managing large subchondral bone cysts. This article outlines a case report and details the pearls and pitfalls of SCP in treating large subchondral bone cysts. Our patient underwent arthroscopic debridement with medial femoral condyle SCP. Mild posterior extravasation of synthetic bone substitute was observed on Postoperative Day 1, which was immediately rectified on revision arthroscopy. Gradual escalation of weight bearing and good pain relief were subsequently achieved, and the patient has remained complication-free after two years. No further extravasation were observed on repeat radiography. SCP is a feasible temporising measure that may help to delay the need for bone allograft or immediate knee arthroplasty in younger patients while retaining function and delaying loss of productivity.

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.

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.

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.

Cannulated versus non-cannulated cancellous screw fixation for femoral neck fractures: a synthetic bone biomechanical study

PURPOSE

To compare the compressive strength of cannulated versus non-cannulated cancellous screws for undisplaced femoral neck fractures in synthetic bones.

METHODS

18 synthetic proximal femurs simulating an AO B1 valgus impacted femoral neck fracture in osteoporotic bone were used. The fracture angles were between 55º and 63º (Pauwels grade 2). Fixation was made using 6.5-mm non-cannulated screws (n=6), 6.5-mm cannulated screws (n=6), or 7.3-mm cannulated screws (n=6). A custom-built jig was designed to guide the insertion of the screws in an identical triangular configuration. Screws were tightened by a single operator using a torque-measuring screwdriver. The femoral head was subjected to progressive axial loading at 5 mm/min. The load to failure and displacement were recorded.

RESULTS

The 3 groups did not differ significantly except that the load to failure was higher in the construct with 6.5-mm non-cannulated screws than that with 6.5-mm cannulated screws (1222 N vs 1008 N, p=0.003).

CONCLUSION

The compressive strength of a synthetic bone hip fracture model fixed with non-cannulated screws was higher than that of cannulated screws of the same diameter.

A Normative Anatomic Study of the Glenohumeral Joint and Rotator Cuff Tendons

Introduction:

The purpose of this study is to determine normative values relating to the glenohumeral joint and rotator cuff tendons namely length, width, thickness and footprint of supraspinatus (SS), infraspinatus (IS), teres minor ™ and subscapularis (SC) from 19 specimens.

Methods:

Rotator cuff tendons and humerus dimensions were measured directly using a digital vernier calliper. In addition, moduli values of rotator cuff tendons were obtained from tensile tests on twelve cadaveric shoulders. The tendon footprints were delineated onto a tracing paper and their dimensions were calculated using digitiser software. The glenoid dimensions were obtained from marking its outline onto a tracing paper and the cavity dimensions from wax moulds. The results were tabulated and statistical analyses, including Student's t-test and ANOVA, were performed.

Conclusion:

The normative anatomic values obtained can be used in finite element modeling, computer simulation, design of implants and surgery.

Patellar resection during total knee arthroplasty: effect on bone strain and fracture risk

Patellae in small knees, or after severe patellar erosion, may be vulnerable to fracture after resection during arthroplasty. The patellar remnant may be thin, while the polyethylene component has a standard thickness. Anterior patellar bone strain was measured in cadaver knees loaded via the quadriceps, from 0 to 90 degrees flexion, with the patella intact, and after resections to 16, 13 and 11 mm thick and replacement by an 8-mm-thick polyethylene component. Strain increased significantly with knee flexion with constant 500 N quadriceps tension. Resection caused significant changes from intact values in knee flexion and extension and no significant effect at 30 degrees flexion. In flexion, bending caused the anterior surface to become more convex, with high tensile bone strains. In extension, resection caused negative anterior strains, representing bending in the opposite direction, with large tensile strains on the cut posterior surface. For normal activities, such as rising from a chair (1.8 kN quadriceps tension) the patella appears safe against fracture with a minimal resection to 16 mm thick. An eroded patella resected to 11 mm thickness may be at risk of fracture with that loading.