Partial subscapularis tear: State-of-the-art.

The subscapularis (SSC) muscle is a crucial anterior glenohumeral stabilizer and internal rotator of the shoulder joint. The partial tears of the SSC might result from traumatic injury or intrinsic degeneration. Partial SSC tears can range in severity and be classified into different categories based on the location of the tear, size of the lesion, and associated pathology. The tear usually begins from the superolateral margin in the first facet and propagates downwards. It is frequently associated with biceps pathology or anterosuperior lesions. These tears are now increasingly recognized as distinct pathology that requires specific diagnostic and management approaches. The current management approaches are shifting towards operative, as partial SSC tears are increasingly recognized as a distinct pathology. At present, there is no consensus regarding the timing of repair, but the relative tendency of the SSC to retract much faster than other rotator cuff muscles, and difficulty in mobilization, advocates an early repair for SSC irrespective of the lesion size. An associated biceps pathology can be treated with either tenotomy (biceps delamination/erosion) or tenodesis. The techniques of partial SSC repair are constantly improving. There is no reported difference in use of 2-anchor-based conventional single-row (SR), a 3-anchor-based interconnected double-row technique, or a 2-anchor-based interconnected hybrid double-row construct in the repair construct. However, the 2-anchor-based interconnected double-row provides an advantage of better superolateral coverage with leading-edge protection, as it helps in placing the superolateral anchor superior and lateral to the original footprint. A timely intervention and restoration of the footprint will help restore and rehabilitate the shoulder. Future directions should prioritise injury prevention, early diagnosis with clinic-radiological cues and targeted interventions to mitigate risk.

All-suture anchor size and drill angle influence load to failure in a porcine model of subpectoral biceps tenodesis, a biomechanical study.

BACKGROUND: Tenodesis of the long head of the biceps tendon is frequently performed in shoulder surgery, and all-suture anchors have become more popular as fixation methods. However, uncertainty still exists regarding the ultimate load to failure of all-suture anchors and the best insertion angle at a cortical humeral insertion point. PURPOSE: The purpose of this study was to compare the biomechanical characteristics of three types of all-suture anchors frequently used for biceps tenodesis. In addition, the influence of two different insertion angles was observed in a porcine humeri model. METHODS: The ultimate load to failure and failure mode of three types of all-suture anchors (1.6 FiberTak®, 1.9 FiberTak®, 2.6 FiberTak®, Arthrex®) applicable for subpectoral biceps tenodesis were evaluated at 90° and 45° insertion angles in 12 fresh-frozen porcine humeri. The anchors were inserted equally alternated in a randomized manner at three different insertion sites along the bicipital groove, and the suture tapes were knotted around a rod for pullout testing. In total, 36 anchors were evaluated in a universal testing machine (Zwick & Roell). RESULTS: The 2.6 FiberTak® shows higher ultimate loads to failure with a 90° insertion angle (944.0 N ± 169.7 N; 537.0 N ± 308.8 N) compared to the 1.9 FiberTak® (677.8 N ± 57.7 N; 426.3 N ± 167.0 N, p-value: 0.0080) and 1.6 FiberTak® (733.0 N ± 67.6 N; 450.0 N ± 155.8 N, p-value: 0.0018). All anchor types show significantly higher ultimate loads to failure and smaller standard deviations at the 90° insertion angle than at the 45° insertion angle. The major failure mode was anchor pullout. Only the 2.6 FiberTak® anchors showed suture breakage as the major failure mode when placed with a 90° insertion angle. CONCLUSIONS: All three all-suture anchors are suitable fixation methods for subpectoral biceps tenodesis. Regarding our data, we recommend 90° as the optimum insertion angle. CLINICAL RELEVANCE: The influence of anchor size and insertion angle of an all-suture anchor should be known by the surgeon for optimizing ultimate loads to failure and for achieving a secure fixation.

Partial ruptures of the distal triceps tendons show only slightly lower ultimate load to failure: a biomechanical study.

OBJECTIVE: Partial ruptures of the distal triceps tendon are usually treated surgically from a size of > 50% tendon involvement. The aim of this study was to compare the ultimate load to failure of intact triceps tendons with partially ruptured tendons and describe the rupture mechanism. METHODS: Eighteen human fresh-frozen cadaveric elbow specimens were randomly assigned to two groups with either an intact distal triceps tendon or with a simulated partial rupture of 50% of the tendon. A continuous traction on the distal triceps tendon was applied to provoke a complete tendon rupture. The maximum required ultimate load to failure of the tendon in N was measured. In addition, video recordings of the ruptures of the intact tendons were performed and analysed by two independent investigators. RESULTS: A median ultimate load to failure of 1,390 N (range Q0.25-Q0.75, 954 - 2,360) was measured in intact distal triceps tendons. The median ultimate load to failure of the partially ruptured tendons was 1,330 N (range Q0.25-Q0.75, 1,130 - 1.470 N). The differences were not significant. All recorded ruptures began in the superficial tendon portion, and seven out of nine tendons in the lateral tendon portion. DISCUSSION: Partial ruptures of the distal triceps tendon demonstrate a not statistically significant lower ultimate load to failure than intact tendons and typically occur in the superficial, lateral portion of the tendon. This finding can be helpful when deciding between surgical and conservative therapy for partial ruptures of the distal triceps tendon.

[Importance and application of injury prevention in Austrian football - a survey among 687 coaches]. / Stellenwert und Anwendung der Verletzungsprävention im österreichischen Fußball ­ eine Befragung unter 687 Trainer/innen.

BACKGROUND: Soccer is one of the most popular sports in the world but associated with a high risk of injury. For this reason, the study of the etiology of injuries is of great interest and numerous prevention programs have been developed in recent years. Since these prevention programs must be embedded into training routine, trainers are primarily responsible for their implementation. The present study aimed to survey Austrian soccer coaches engaged in professional, amateur or youth teams with respect to their opinions on injuries as well as the application of respective prevention programs. METHODS: An online questionnaire was developed and sent to all coaches registered in the Austrian Football Association.In addition to personal data, the trainers' attitudes to the subject of injury prevention were also asked. It was also asked which preventive measures the trainers consider important and which they also use in their training and to what extent. RESULTS: A total of 687 trainers took part in the survey. 2,3%, 37,5% and 43,6% of trainers were engaged in professional, amateur and youth clubs, respectively. The rest gave no information. The majority of respondents (56%) considered injuries a major concern in soccer. Inadequate fitness (75,7%) as well as insufficient preparation (60,7%) and poor regeneration (59,2%) were seen as the greatest risk factors for injuries. Appropriate warm-up (66,8%), regeneration (59,4%) and core stabilization training (58,2%) were considered the most effective preventative measures. More than 50% of the participants were not familiar with any of the most widely applied injury prevention programs, and only 15.4% actually implemented those programs in their training.The substantial interest in injury prevention notwithstanding, the respective standard of knowledge amongst Austrian coaches is poor. In light of the high prevalence of injuries, it is most important to inform trainers about injury prevention programs and possibilities to implement them in training practice.

Clinical outcome and healing rate after meniscal bucket handle tear repair.

BACKGROUND: Reports combining patient-reported outcome measures, clinical evaluation, and radiographic assessment of postoperative healing after arthroscopic repair of bucket-handle meniscal tears (BHMT) are scarce. METHODS: Patients who underwent arthroscopic repair for acute traumatic BHMTs between October 2011 and March 2016 with a minimum follow-up of two years were included. Postoperative outcome scores comprised the International Knee Documentation Society Score (IKDC), Lysholm score, Tegner activity score (TAS), and visual analog scale (VAS) for pain. Clinical meniscal healing failure was assessed according to Barrett's criteria. Side-to-side difference in knee laxity was measured using KT-2000. Radiographic healing was assessed by 3-Tesla magnetic resonance imaging (MRI) and classified according to Henning's criteria at final follow-up. RESULTS: Forty patients with a mean age of 32.0 ± 11.5 years were available for follow-up after 51.8 ± 14.3 months. Revision surgery by means of arthroscopic partial meniscectomy was performed in four patients (10%) prior to the follow-up visit. The clinical healing rate was 83.3% at final follow-up. Mean IKDC score was 82.8 ± 13.8 and Lysholm score was 77.4 ± 24.8. Of all patients, 87.5% reached or exceeded the patient-acceptable symptomatic state (PASS) criteria for the IKDC score at final follow-up. The median TAS was 6 and VAS for pain was 0.46 ± 0.9. Side-to-side difference in knee laxity was higher in patients with concomitant ACL reconstruction (2.1 ± 2.7 mm) compared to isolated BHMTs (1.0 ± 2.0 mm). MR examination showed 69.4% healed, 25.0% partially healed, and 5.6% unhealed menisci. CONCLUSION: Patients who underwent repair for acute traumatic BHMTs achieved good to excellent clinical outcome along with a high rate of meniscal healing at a minimum follow-up of two years. Clinical and radiological healing rates were similarly satisfactory and most patients exceeded the PASS criteria for the IKDC score. Patients were able to reach a high postoperative activity level. LEVEL OF EVIDENCE: Case Series; IV.

Center of pressure (COP) measurement in patients with confirmed successful outcomes following shoulder surgery show significant sensorimotor deficits.

PURPOSE: To determine the sensorimotor and clinical function of patients with confirmed successful outcome after either undergoing acromioclavicular joint (ACJ) stabilization, Bankart repair (BR), or rotator cuff repair (RC), and to compare these measures to the contralateral, healthy side without history of previous injuries or surgeries of the upper extremity. It was hypothesized that patients of each interventional group would have inferior sensorimotor function of the shoulder joint compared to the contralateral, healthy side, while presenting with successful clinical and functional outcomes. METHODS: Three intervention groups including ten patients who had confirmed successful clinical and functional outcomes after either undergoing ACJ stabilization, BR, or RC were evaluated postoperatively at an average follow-up of 31.7 ± 11.6 months. Additionally, a healthy control group (CG) of ten patients was included. Clinical outcomes were assessed using the Constant-Murley (CM) and American Shoulder and Elbow Surgeons (ASES) Score. Pain was evaluated using the visual analogue scale (VAS). Sensorimotor function was assessed by determining the center of pressure (COP) of the shoulder joint in a one-handed support task in supine position on a validated pressure plate. RESULTS: Each interventional group demonstrated excellent clinical outcome scores including the CM Score (ACJ 83.3 ± 11.8; BR 89.0 ± 10.3; RC 81.4 ± 8.8), ASES Score (ACJ 95.5 ± 7.0; BR 92.5 ± 9.6; RC 96.5 ± 5.2), and VAS (ACJ 0.5 ± 0.9; BR 0.5 ± 0.8; RC 0.5 ± 0.8). Overall, the CG showed no significant side-to-side difference in COP, whereas the ACJ-group and the BR-group demonstrated significantly increased COP compared to the healthy side (ACJ 103 cm vs. 98 cm, p = 0.049; BR: 116 cm vs. 102 cm, p = 0.006). The RC-group revealed no significant side-to-side difference (120 cm vs. 108 cm, n.s.). CONCLUSION: Centre of pressure measurement detected sensorimotor functional deficits following surgical treatment of the shoulder joint in patients with confirmed successful clinical and functional outcomes. This may indicate that specific postoperative training and rehabilitation protocols should be established for patients who underwent surgery of the upper extremity. These results underline that sensorimotor training should be an important component of postoperative rehabilitation and physiotherapeutic activities to improve postoperative function and joint control. LEVEL OF EVIDENCE: IV.

Limited evidence for biological treatment measures for cartilage and tendon injuries of the shoulder.

PURPOSE: To critically review the available literature on the usage of biologics to treat cartilage and tendon injuries of the shoulder. METHODS: Four different databases were searched in January 2020 for studies reporting data on bone marrow stimulation, autologous chondrocyte implantation, platelet-rich plasma, autologous concentrated serum, and bone marrow aspirate concentrate for the treatment of cartilage and/or tendon injuries of the shoulder. Prospective, retrospective, cohort and case-control studies as well as case series, systematic reviews and laboratory studies (involving human tissue) were included. Cadaveric or animal studies were excluded. Findings were summarized and an expert opinion on trends was provided. RESULTS: Although there is limited literature available on biologics in cartilage lesions of the shoulder, the advancement from micro- to nanofracture, that is well established for the treatment of cartilage lesions in the knee, may be the next step in the treatment of shoulder lesions as well. The high rate of failure and therefore the complexity of tendon healing following rotator cuff repair has led to a rising interest in biologic augmentation such as platelet-rich plasma and stem cells to enhance tendon-bone-healing and to decrease the prevalence of failure. Despite the increase in publications, there exists a huge heterogeneity of content, quality, and quantity of among studies and their processing methods reporting the use of platelet-rich plasma in rotator cuff repair. CONCLUSION: Conclusions from individual studies cannot be generalized. Currently, no evidence supports that platelet-rich plasma provides clinical benefits in rotator cuff repair. Similar is reported for microfracture in rotator cuff repair, however, despite no clinical benefits, microfracture has shown to reduce the appearance of structural failures. Although some evidence exists for the use of stem cells form bone marrow aspirate concentrate, results from large case series are still lacking. LEVEL OF EVIDENCE: Level V.

Biceps Brachii Alterations Following the Latarjet Procedure: A Prospective Multicenter Study.

PURPOSE: To prospectively investigate the postoperative forearm supination and elbow flexion strength of both upper extremities and popeye deformity in patients who underwent a mini-open Latarjet procedure for anterior shoulder instability. METHODS: Patients who underwent a mini-open Latarjet procedure at two specialized shoulder centers were prospectively evaluated preoperatively (T0) and at least 6 months (T1) after surgery. Subjects were tested for elbow flexion and forearm supination strength of both upper extremities using an isometric dynamometer and customized torque dynamometer. Clinical outcome was assessed by the Constant Score (CS), American Shoulder and Elbow Score (ASES) and Simple Shoulder test (SST). Popeye deformity was defined as a distalization of the greatest circumference of the biceps muscle belly towards the lateral epicondyle of the elbow. RESULTS: A total of 20 patients with a mean age of 27 ± 6 years were included in the study. At a mean follow-up of 10 ± 3 months, the elbow flexion strength was restored to the preoperative state (p = 0.240). Forearm supination strength significantly decreased at final follow-up, to 88 % in the surgical arm (p = 0.015) vs. 90 % in the non-surgical arm (p = 0.023). There was no statistical difference when comparing both arms concerning elbow flexion strength (p = 0.510) and forearm supination strength (p = 0.495). No significant popeye deformity was observed in both arms (p = 0.111 vs. p = 0.508). Clinical outcome scores improved significantly from 73 ± 18 to 82 ± 13 (p = 0.014) for CS and 76 ± 22 to 89 ± 12 (p = 0.008) for ASES score preoperatively to final follow-up. No difference in the SST was documented (p = 0.10). CONCLUSION: The Latarjet procedure showed to preserve elbow flexion strength and provided comparable forearm supination strength compared to the uninjured arm with reliable clinical outcome in this study population. However, a decrease of forearm supination strength in both arms was persistent at a mean of 10 months postoperatively. No popeye deformity was noted in the postoperative examinations. LEVEL OF EVIDENCE: Case series, Level III.

The evaluation of Rolimeter, KLT, KiRA and KT-1000 arthrometer in healthy individuals shows acceptable intra-rater but poor inter-rater reliability in the measurement of anterior tibial knee translation.

PURPOSE: To assess measurement equivalence, inter- and intra-rater reliability, standard error of measurements (SEM) and false positive measurements (FPM) of four different knee arthrometers (KLT,Karl Storz; KiRA, I + ; KT-1000 MEDmetric Corp; Rolimeter, Aircast) in healthy patients. METHODS: Four different investigators (two advanced (AR) and two beginners (BR)) examined 12 participants with healthy knees at two time points with regards to anterior tibial translation (ATT) and side-to-side difference (SSD). Test equivalence was assessed using the TOST (two-one-sided t test) procedure with ± 1 mm equivalence boundaries. Intraclass correlation coefficients (ICCs) were calculated using two-way mixed effects models. Furthermore, false positive-(SSD > 3 mm) and SEMs were assessed. RESULTS: A total of 2304 Lachman Tests were performed. Between-rater SSDs were equivalent between AR and BR raters for the Rolimeter only. Inter-rater ICC values (SSD, ATT) were graded as "poor" to "moderate" for all devices. Equivalent test-retest results were observed for all raters using the Rolimeter, KLT and KT-1000, whereas measurement consistency with KiRA was given in the advanced examiners group only. Intra-rater ICC values (Range: SSD, ATT) were graded as "poor" to "moderate" for SSD values and "moderate" to "good" for ATT. SEMs were lowest for the Rolimeter and highest for KiRA. FPM were never obtained with the Rolimeter (0%), twice (2.1%) with the KT-1000, three times (3.1%) with the KLT and 33 times (34.4%) using KiRA. CONCLUSION: There is acceptable intra-rater but poor inter-rater reliability with all tested arthrometers. Measures of knee laxity are comparable between Rolimeter, KLT and KT-1000 but higher for KiRA. Clinically, the present study shows that repeated arthrometry measurements should always be performed by the same investigators.

Additional acromioclavicular cerclage limits lateral tilt of the scapula in patients with arthroscopically assisted coracoclavicular ligament reconstruction.

INTRODUCTION: The current treatment for acromioclavicular (AC) dislocation lacks a gold standard and previous literature concludes that coracoclavicular (CC) fixation with additional AC cerclage fixation adds stability and is a useful adjunct to augment these repairs. AIM: The purpose of this study was to investigate the clinical and radiological value of an additional AC cerclage. It was hypothesised that an additional AC cerclage would show better clinical results. We further expected the additional AC cerclage to result in lower radiological loss of reduction compared to the technique relying on CC-fixation only. METHODS: A total of 30 male patients with acute (less than 3 weeks) AC-dislocations Rockwood grade IV and V from 2013 to 2014 underwent arthroscopic bi-cortical CC-ligament reconstruction. Patients were assigned to a surgeon depending on the day of clinical presentation. One surgeon used only bi-cortical CC-ligament reconstruction (no-PDS group); the other surgeons used an additional PDS cerclage with an 8-loop configuration over the AC joint (PDS group). Clinical data (Constant Shoulder Score, ASES Score, DASH Score, VAS pain) were assessed 24 months post-operatively, and AP shoulder radiographs used to measure the AC and CC distances. RESULTS: No significant differences in the Constant (Z = - 0.498, p = 0.624), ASES (Z = 0.263, p = 0.806) and DASH (Z = 1.097, p = 0.305) score as well as VAS pain (Z = 0.498, p = 0.624) were seen for both groups. Factorial ANOVA showed a significant effect of "time" [F(1,28) = 17.54, p < 0.001, r = 0.62], reflecting a significant radiological increase of AC distances over time for both groups. Comparing CC and CC + AC groups, the effect of "OP technique" was significant [F(1,28) = 4.67, p = 0.039, r = 0.38], with AC distances obtained in the PDS group being statistically lower than in the No-PDS group, whereas CC distances did not significantly increase in both groups [F(1,28) = 0.07, p = 0.791]. "Time × OP technique" interaction effects were non-significant [F(1,28) = 0.38, p = 0.545], which reflects similar changes in AC distances over time in both groups. For the CC distances, neither main nor interaction effects were significant (all p > 0.05). CONCLUSION: Both the isolated CC reconstruction and the CC reconstruction with an additional AC cerclage showed good clinical results at 2 years' follow-up. AC distances increased in both groups from the post-surgery measurement to the 2-year follow-up, but were generally lower with an additional AC cerclage. CC distances did not increase significantly over time in both groups. Therefore, the presented data suggest adding a fixation of the AC joint.

Combined posterolateral knee reconstruction: ACL-based injuries perform better compared to PCL-based injuries.

PURPOSE: To compare post-operative physical activity and return to work after combined posterolateral corner (PLC) reconstruction (PLC-R) in anterior cruciate ligament (ACL)- or posterior cruciate ligament (PCL)-based injuries. METHODS: Patients aged > 18 years undergoing PLC-R using the Larson technique combined with either ACL or PCL reconstruction were included. Outcome was evaluated retrospectively after a minimum follow-up of 24 months using Tegner Activity Scale, Activity Rating Scale (ARS), Knee Injury and Osteoarthritis Outcome Score (KOOS), work intensity according to REFA classification, and a questionnaire about type of occupation and time to return to work. RESULTS: A total of 32 patients (11 ACL-based injuries and 21 PCL-based injuries) were included. Mean follow-up was 56 ± 26 months in the ACL-based injury group and 59 ± 24 months in the PCL-based injury group. All patients in the ACL-based injury group and 91% of patients in the PCL-based injury group returned to sports activities. Comparing pre- and post-operative values, a significant deterioration of the Tegner Activity Scale and ARS was observed in the PCL-based injury group, whereas no significant change was observed in the ACL-based injury group. KOOS subscales were generally higher in the ACL-based injury with significant differences in the subscale sports and recreational activities. Patients with ACL-based injuries returned to work significantly earlier compared to patients with PCL-based injuries (11 ± 4 weeks vs. 21 ± 10 weeks, p < 0.05). CONCLUSION: High rates of return to sports and work can be expected after combined PLC-R in both ACL- and PCL-based injuries. However, deterioration of sports ability must be expected in PCL-based injuries. ACL-based injuries led to superior patient-reported outcomes and an earlier return to work, as compared to PCL-based injuries. LEVEL OF EVIDENCE: Level IV.

Remodeling the Skeletal Muscle Extracellular Matrix in Older Age-Effects of Acute Exercise Stimuli on Gene Expression.

With advancing age, the skeletal muscle extracellular matrix (ECM) undergoes fibrotic changes that may lead to increased muscle stiffness, injury susceptibility and strength loss. This study tested the potential of different exercises to counter these changes by stimulating the activity of genes associated with ECM remodeling. Twenty-six healthy men (66.9 ± 3.9 years) were stratified to two of four groups, performing unilateral (i) conventional resistance exercise, (ii) conventional resistance exercise followed by self-myofascial release (CEBR), (iii) eccentric-only exercise (ECC) or (iv) plyometric jumps (PLY). The non-trained leg served as control. Six hours post-exercise, vastus lateralis muscle biopsy samples were analyzed for the expression of genes associated with ECM collagen synthesis (COL1A1), matrix metallopeptidases (collagen degradation; MMPs) and peptidase inhibitors (TIMP1). Significant between-group differences were found for MMP3, MMP15 and TIMP1, with the greatest responses in MMP3 and TIMP1 seen in CEBR and in MMP15 in ECC. MMP9 (3.24-3.81-fold change) and COL1A1 (1.47-2.40-fold change) were increased in CEBR and PLY, although between-group differences were non-significant. The expression of ECM-related genes is exercise-specific, with CEBR and PLY triggering either earlier or stronger remodeling than other stimuli. Training studies will test whether execution of such exercises may help counter age-associated muscle fibrosis.

Sternoclavicular Joint Reconstruction Fracture Risk Is Reduced With Straight Drill Tunnels and Optimized With Tendon Graft Suture Augmentation.

BACKGROUND: Despite the rare entity of sternoclavicular joint (SCJ) instability, a variety of different reconstruction techniques for SCJ dislocations have been described. A technique with oblique drilling has been proposed to reduce intraoperative risks. PURPOSE: To biomechanically investigate different cerclage reconstruction techniques and the benefit of additional reinforcement using suture tape. STUDY DESIGN: Controlled laboratory study. METHODS: Reconstructed artificial bone specimens were mounted on a mechanical testing machine. They were subjected to anterior and posterior translation, analyzing ultimate strength, displacement, stiffness, and elongation. For stage 1, different angulations of the drill tunnels through the sternum and clavicle were compared. Straight drill tunnels from anterior to posterior were compared with 45° oblique drill tunnels. For stage 2, three different materials for cerclage reconstruction were compared: (1) suture tape alone (FT group), (2) tendon graft alone (tendon group), and (3) tendon graft with suture tape augmentation (tendon+FT group). RESULTS: For the FT group, in the anterior and posterior directions, straight drill holes resulted in a significantly higher load to failure (936.9 ± 122.5 N) compared with oblique ones (434.5 ± 20.2 N) (P < .0001). During cyclic testing, all specimens with straight drill holes survived the 5- to 550-N step, while all specimens with oblique ones failed during the 5- to 450-N step. Analyzing the graft material choice, the mean load to failure was 556.6 ± 174.3 N for the tendon group, 936.9 ± 122.5 N for the FT group, and 767.0 ± 110.7 N for the tendon+FT group (P = .089). The stiffness of the tendon+FT group was significantly lower than that of the FT group and significantly higher than that of the tendon group. CONCLUSION: Oblique tunnel placement during SCJ reconstruction, while reducing the intraoperative risk, results in decreased primary stability of the construct. Tendon graft reconstruction with suture tape augmentation leads to enhanced stability and optimizes biomechanical properties of the construct. CLINICAL RELEVANCE: The surgical technique with straight drill holes has superior initial biomechanical properties and may likewise produce superior clinical outcomes in the treatment of SCJ instability. Suture tape augmentation can provide additional stability to reconstruction procedures.

A Superolaterally Placed Anchor for Subscapularis "Leading-Edge" Refixation: A Biomechanical Study.

PURPOSE: To compare a conventional single-row (SR) repair technique and 2 double-row (DR) repair techniques to restore and protect the superolateral aspect of the subscapularis (SSC) tendon and ensure SSC leading-edge reconstruction in a cadaveric model. METHODS: The native footprint was measured in 15 pairs of human cadaveric shoulders (N = 30) with a mean age of 67.2 years. According to the Fox-Romeo classification, a 25% defect or 50% defect in a superior-inferior direction was created. Specimens were mounted onto a servohydraulic test system to analyze contact variables at 0° and 20° of abduction with a force-controlled ramped program up to 50 N. In addition, each specimen was cyclically loaded (10-100 N, 300 cycles). The tears were repaired with 1 of 3 constructs: a 2-anchor medially based conventional SR construct, a 2-anchor-based hybrid DR construct, or a 3-anchor-based DR construct. The outcome variables were ultimate tensile load, displacement, and pressurized footprint coverage. RESULTS: All reconstructions resulted in stable constructs with peak loads exceeding 450 N (P = .68). The overall displacement during cyclic loading was between 1.2 and 3.0 mm (P = .70). A significant difference was seen when the 2 arm positions of 0° and 20° of abduction were compared, showing a constant reduction of pressurized footprint coverage with the arm abducted (P = .01). Analyzing footprint coverage with respect to the region of interest-the leading edge of the SSC-we observed a significant difference between the SR construct and a construct using a superolaterally placed anchor (25% defect, P = .01; 50% defect, P = .01), whereas no statistical differences were detectable between the hybrid DR construct and the DR construct. CONCLUSIONS: The leading edge of the SSC tendon can best be restored by using a superolateral anchor, whereas no statistical difference in load to failure in comparison with an SR construct or with the addition of a third anchor was detectable. CLINICAL RELEVANCE: The SSC is critical for proper shoulder function. Without an increase in the number of implants, a significantly better footprint reconstruction can be achieved by placing an anchor superior and lateral to the native footprint area close to the entrance of the bicipital groove.

Insufficient consensus regarding circle size and bone loss width using the ratio-"best fit circle"-method even with three-dimensional computed tomography.

PURPOSE: Glenoid bone integrity is crucial for shoulder stability. The purpose of this study was to investigate a non-invasive method for quantifying bone loss regarding reliability and accuracy to detect glenoid bone deficiency in standard two-dimensional (2D) and three-dimensional (3D) computed tomography (CT) measurements at different time points. It was hypothesized that the diameter of the circle used would significantly differ between raters, rendering this method inaccurate and not allowing for an exact estimation of glenoid defect size. METHODS: Fifty-two shoulder CTs from 26 patients (26 2D-CTs; 26 3D-CTs) with anterior glenoid bone defects were evaluated by 6 raters at time 0 (T0) and at least 3 weeks after (T1) to assess the glenoid bone defect using the ratio method ("best fit circle"). Inter- and intra-rater differences concerning circle dimensions (circle diameter), measured width of bone loss and calculated percentage of bone loss (length-width-ratio) were compared in 2D- versus 3D-CT scans. The intraclass coefficient (ICC) was used to determine the inter- and intra-rater agreement. RESULTS: The mean circle diameter difference in 2D-CT was 2.0 ± 1.9 mm versus 1.8 ± 1.5 mm in 3D-CT, respectively (p < 0.01). Mean width of bone loss in 2D-CT was 1.9 ± 1.7 mm compared to 1.7 ± 1.5 mm in 3D-CT, respectively (p < 0.01). The mean difference of bone loss percentage was 5.1 ± 4.8% in 2D-CT and 4.8 ± 4.5% in 3D-CT (p < 0.01). No significant differences concerning circle diameter, bone loss width and bone loss percentage were detected comparing T0 and T1. Circle diameter, bone loss width and bone loss percentage measurements in 3D-CT were significantly smaller compared to 2D-CT at T0 and T1 (p < 0.01). Agreement (ICC) was fair to good for all indicators of circle diameter (range 0.76-0.83), bone loss width (range 0.76-0.86) and percentage of bone loss (range 0.85-0.91). Overall, 3D-CT showed superior agreement compared to 2D-CT. CONCLUSION: The ratio method varies in all glenoid parameters and is not valid for consistently quantifying glenoid bone defects even in 3D computed tomography. This must be taken into consideration when determining proper surgical treatment. The degree of glenoid bone loss alone should not be used to decide for or against a bony procedure. Rather, it is more important to define a defect size as "critical" and to also take other patient-specific factors into consideration so that the best treatment option can be undertaken. Application of the "best fitting circle" is a source of error when using the ratio method; therefore, care should be taken when measuring the circle diameter. LEVEL OF EVIDENCE: III.

Posterior open wedge glenoid osteotomy provides reliable results in young patients with increased glenoid retroversion and posterior shoulder instability.

PURPOSE: The relationship between posterior shoulder instability and increased glenoid retroversion has been documented. Posterior open wedge glenoid osteotomy is a possible treatment option for patients with increased glenoid retroversion, but outcomes in the literature are limited. Therefore, the purpose of this study was to report the clinical and radiological outcomes following posterior glenoid osteotomy. METHODS: Patients that underwent posterior glenoid osteotomy for posterior shoulder instability with a GR angle of more than or equal to 10°, and were at least 12 months out from surgery, were included in the study. General data, medical history, and radiographic data such as the pre- and postoperative glenoid retroversion angle were extracted from the patients' hospital documentation notes. To evaluate the postoperative outcome, the Rowe standard rating scale for shoulder instability and the Oxford shoulder instability score were collected retrospectively. RESULTS: A total of 12 shoulders (11 patients) could be included. The mean pre-operative glenoid retroversion was 23.3° (range 12°-35°) and this reduced significantly (p = 0.003) to a mean of 13° (range 1°-28°) postoperatively. At a mean follow-up of 19.8 months (range 14-36), the median Rowe score was 90 points (range 45-100 points) and the median Oxford instability score was 44 points (range 21-48 points). There were no postoperative re-dislocations or revision surgeries; however, one patient reported signs of recurrent shoulder instability and four asymptomatic glenoid neck fractures occurred. CONCLUSION: Open wedge posterior glenoid osteotomy provides reliable clinical results with a low rate of clinical failure in a stringently selected patient cohort at short-term follow-up. However, due to the risk of potentially severe complications, we advocate this procedure for experienced shoulder surgeons only, who are familiar with its anatomical and technical considerations. LEVEL OF EVIDENCE: IV (case series).

Cartilage repair surgery prevents progression of knee degeneration.

PURPOSE: To investigate, whether cartilage repair surgery for focal osteochondral defects at the knee results in less degenerative changes over 6 years in a MR imaging follow-up than morphologically initially identical defects in non-operated control subjects from the osteoarthritis initiative (OAI). METHODS: A total of 32 individuals received baseline and follow-up MRI. In n = 16 patients with cartilage repair [osteochondral autograft transfer system (OATS), n = 12; spongiosa-augmented matrix-associated autologous chondrocyte implantation (MACI), n = 4] MRI was performed preoperatively and after 5.7 ± 2.3 year follow-up. Baseline MRIs of non-operated subjects from the OAI were screened for initially identical cartilage defects (n = 16). Morphological knee abnormalities were assessed using WORMS, AMADEUS and MOCART scores. A sagittal 2D MSME sequence was implemented for quantitative cartilage T2 relaxation time measurements in all (0, 2, 4, 6 and 8-years) follow-ups from the OAI and in the postoperative MRI protocol. RESULTS: For both groups, focal osteochondral defects were located at the femoral condyle in 8/16 cases (5 medial, 3 lateral) and at the patella in 8/16 cases. At baseline, the mean cartilage defect size ± SD was 1.4 ± 1.3 cm2 for the control group and 1.3 ± 1.2 cm2 for the cartilage repair group (n.s.). WORMS scores were not significantly different between the cartilage repair group and the control group at baseline [mean difference ± SEM (95%CI); 0.5 ± 2.5 (- 4.7, 5.7), n.s.]. During identical follow-up times, the progression of total WORMS scores [19.9 ± 2.3 (15.0, 24.9), P < 0.001] and of cartilage defects scores in the affected (P < 0.001) and in the opposing (P = 0.029) compartment was significantly more severe in non-operated individuals (P < 0.05). In non-operated subjects, T2 values increased continuously from baseline to the 8-year follow-up (P = 0.001). CONCLUSIONS: Patients with cartilage repair showed less progression of degenerative MRI changes at 6-year follow-up than a control cohort from the OAI with initially identical osteochondral defects. Patients with focal cartilage defects may profit from cartilage repair surgery since it may prevent progression of early osteoarthritis at the knee joint. LEVEL OF EVIDENCE: Prognostic study, Level II.

Primary Stability of an Acromioclavicular Joint Repair Is Affected by the Type of Additional Reconstruction of the Acromioclavicular Capsule.

BACKGROUND: The synergistic effect of the acromioclavicular (AC) capsule and coracoclavicular (CC) ligaments on AC joint stability has gained recent recognition for its importance. Biomechanical and clinical studies have shown the benefit of combined reconstruction with multiple variations of surgical techniques for AC capsule augmentation. The ideal configuration remains unknown for such capsular repair aimed at achieving optimal stability with anatomic reconstruction. HYPOTHESIS: Primary AC joint stability can be restored by AC capsule augmentation, while position of the additional suture construct is critical. It was hypothesized that techniques that reconstruct the anterior capsular structures would restore native stability against rotations and translations. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty fresh-frozen human cadaveric shoulders were used. Each sample was tested in the native state and served as its own control. After complete capsulotomy, 1 of 5 AC capsular repair configurations was performed: anterior, superior, posterior, O-frame, and X-frame. After testing of the AC capsular repair configurations, the tests were repeated after dissection of the CC ligaments and after CC ligament reconstruction with a suture button system. AC joint stability was immediately tested after each step under rotation and horizontal translation. To accomplish this, the AC joints were anatomically positioned on a custom fixture linked to a servohydraulic testing system. A 3-dimensional optical measuring system was used to evaluate the 3-dimensional joint motion. Clavicle posterior translation in relation to the acromion, rotation around the long axis of the clavicle, and displacement of the lateral clavicle in relation to the center of rotation were measured. The torques and forces required to rotate and translate the clavicle were recorded. RESULTS: In terms of translational testing, after the complete capsulotomy, a significant reduction of resistance force was found across all groups, with a mean 13% to 20% remaining ( P < .05). All AC suture augmentations were able to significantly increase the average resistance force as compared with the native ( P = .01) against posterior translation. Subsequent cutting of the CC ligaments did not result in a significant change in any of the groups ( P = .23). The synergistic effect of AC capsule augmentation and CC ligament reconstruction could be demonstrated without exception. In terms of rotational testing, the complete capsulotomy resulted in a significant reduction of resistance torque in all groups ( P < .05), with a remaining torque ranging between 2% and 11% across the groups. However, all AC suture constructs significantly increased the resistance torque as compared with the capsulotomy ( P = .01). The subsequent cutting of the CC ligaments resulted in a significant change in 2 of the 5 groups (O-frame, P = .01; X-frame, P = .02) and an overall remaining torque reduction ranging from 3% and 42%. The combined reconstruction of the AC capsule and CC ligaments achieved the highest percentage of regained resistance torque but remained significantly weaker than the native specimen ( P = .01). CONCLUSION: Native translational stability could be restored by the addition of AC capsule augmentation, while partial rotational instability remained. The tested constructs revealed no significant individual differences. CLINICAL RELEVANCE: Combined stabilization of the AC capsule and CC ligaments demonstrated the greatest capacity to restore the native stability against translational and rotational loads, with the specific configuration of the AC capsule repair to be chosen according to the personal preferences of the surgeon.

Single cut distal femoral osteotomy for correction of femoral torsion and valgus malformity in patellofemoral malalignment - proof of application of new trigonometrical calculations and 3D-printed cutting guides.

BACKGROUND: The purpose of this study was to perform a derotational osteotomy at the distal femur, as is done in cases of patellofemoral instability, and demonstrate the predictability of three-dimensional (3D) changes on axes in a cadaveric model by the use of a new mathematical approach. METHODS: Ten human cadaveric femurs, with increased antetorsion, underwent a visually observed derotational osteotomy at the distal femur by 20°, as is commonly done in clinics. For surgery, a single cut osteotomy with a defined cutting angle was calculated and given using a simple 3D-printed cutting guide per specimen, based on a newly-created trigonometrical model. To simulate post-operative straight frontal alignment in a normal range, a goal for the mechanical lateral distal femur angle (mLDFA) was set to 87.0° for five specimens (87-goal group) and 90.0° for five specimens (90-goal group). Specimens underwent pre- and post-operative radiographic analysis with CT scan for torsion and frontal plane x-ray for alignment measurements of mLDFA and anatomical mechanical angle (AMA). RESULTS: Performed derotation showed a mean of 19.69° ±1.08°SD (95% CI: 18.91° to 20.47°). Regarding frontal alignment, a mean mLDFA of 86.9° ±0.66°SD (87-goal-group) and 90.42° ±0.25° SD (90-goal group), was observed (p = 0.008). Overall, the mean difference between intended mLDFA-goal and post-operatively achieved mLDFA was 0.14° ±0.56° SD (95% CI: -0.26° to 0.54°). CONCLUSION: A preoperative calculated angle for single cut derotational osteotomy at the distal femur leads to a clinically precise post-operative result on torsion and frontal alignment when using this approach.