Christian Gerhardt

Arthroscopically Assisted Stabilization of Acute High-Grade Acromioclavicular Joint Separations

Background: The purpose of this study was to evaluate the clinical and radiological results after arthroscopically assisted and image intensifier–controlled stabilization of high-grade acromioclavicular (AC) joint separations using the double TightRope technique with the first-generation implant. Hypothesis: The double TightRope technique using the first-generation implant leads to good clinical and radiological results by re-creating the anatomy of the AC joint. Study Design: Case series; Level of evidence, 4. Methods: Thirty-seven consecutive patients (4 women and 33 men; mean age, 38.6 years) who sustained an acute AC joint dislocation grade V according to Rockwood were included in this prospective study. The Subjective Shoulder Value (SSV), the Constant Score (CS), the Taft Score (TS), and a newly developed Acromioclavicular Joint Instability Score (ACJI) were used for final follow-up. Bilateral stress views and bilateral Alexander views were taken to evaluate radiographic signs of recurrent vertical and horizontal AC joint instability. Results: Twenty-eight patients (2 women and 26 men; mean age, 38.8 years [range, 18-66 years]) could be evaluated after a mean follow-up of 26.5 months (range, 20.1-32.8 months). The interval from trauma to surgery averaged 7.3 days (range, 0-18 days). The mean SSV reached 95.1% (range, 85%-100%), the mean CS was 91.5 points (range, 84-100) (contralateral side: mean, 92.6 points), the mean TS was 10.5 points (range, 7-12), and the ACJI averaged 79.9 points (range, 45-100). The final coracoclavicular distance was 13.6 mm (range, 5-27 mm) on the operated versus 9.4 mm (range, 4-15 mm) on the contralateral side (P < .05). Radiographic signs of posterior instability were noted in 42.9% of cases. Patients with evidence of posterior instability had significantly inferior results in the TS and the ACJI (P < .05). Neither coracoid fractures nor early (within 6 weeks postoperatively) loss of reduction due to tunnel malpositioning or implant loosening was observed. Conclusion: The combined arthroscopically assisted and image intensifier–controlled double TightRope technique using implants of the first-generation represents a safe technique and yields good to excellent early clinical results despite the presence of partial recurrent vertical and horizontal AC joint instability.

Biomechanical Comparison of 4 Double-Row Suture-Bridging Rotator Cuff Repair Techniques Using Different Medial-Row Configurations

PURPOSE Biomechanical comparison of different suture-bridge configurations of the medial row with respect to initial construct stability (time 0, porcine model). METHODS In 40 porcine fresh-frozen shoulders, the infraspinatus tendons were dissected from their insertions. All specimens were operated on by use of the suture-bridge technique, only differing in terms of the medial-row suture-grasping configuration, and randomized into 4 groups: (1) single-mattress (SM) technique, (2) double-mattress (DM) technique, (3) cross-stitch (CS) technique, and (4) double-pulley (DP) technique. Identical suture anchors were used for all specimens (medial: Bio-Corkscrew FT 5.5 [Arthrex, Naples, FL]; lateral: Bio-PushLock 3.5 [Arthrex]). All repairs were cyclically loaded from 10 to 60 N until 10 to 200 N (20-N stepwise increase after 50 cycles each) with a material testing machine. Forces at 3 and 5 mm of gap formation, mode of failure, and maximum load to failure were recorded. RESULTS The DM technique had the highest ultimate tensile strength (368.6 ± 99.5 N) compared with the DP (248.4 ± 122.7 N), SM (204.3 ± 90 N), and CS (184.9 ± 63.8 N) techniques (P = .004). The DM technique provided maximal force resistance until 3 and 5 mm of gap formation (90.0 ± 18.1 N and 128.0 ± 32.3 N, respectively) compared with the CS (72 ± 8.9 N and 108 ± 20.2 N, respectively), SM (66.0 ± 8.9 N and 90.0 ± 26.9 N, respectively), and DP (62.2 ± 6.2 N and 71 ± 13.2 N, respectively) techniques (P < .05 for each 3 and 5 mm of gap formation). The main failure mode was suture cutting through the tendon. CONCLUSIONS Comparing the 4 different suture-bridge techniques, we found that modified application of suture-bridge repair with double medial mattress stitches significantly enhanced biomechanical construct stability at time 0 in this porcine ex vivo model. CLINICAL RELEVANCE This technique increases initial stability and resistance to suture cutting through the rotator cuff tendon after arthroscopic suture-bridge repair.

Arthroscopic Single-Row Modified Mason-Allen Repair Versus Double-Row Suture Bridge Reconstruction for Supraspinatus Tendon Tears A Matched-Pair Analysis

Background: Arthroscopic double-row fixation of supraspinatus tendon tears compared with single-row techniques is still a matter of debate. Hypothesis: Arthroscopic double-row rotator cuff repair using the suture bridge technique provides better clinical results and lower retear rates than does single-row repair using a modified Mason-Allen stitch technique. Study Design: Cohort study; Level of evidence 3. Methods: Forty patients underwent either an arthroscopic single-row modified Mason-Allen stitch (SR) (n = 20; mean age ± SD, 61.5 ± 7.4 y) or a modified suture bridge double-row repair (DR) (n = 20; age, 61.2 ± 7.5 y). The anteroposterior extension was classified as Bateman I in 10% and Bateman II in 90% of patients in the SR group and as Bateman II in 80% and Bateman III in 20% of patients in the DR group. Patients were matched for sex and age. The subjective shoulder value (SSV), Constant-Murley score (CS), and Western Ontario Rotator Cuff Index (WORC) were used for clinical follow-up. Furthermore, MRI scans were conducted for analysis of tendon integrity, muscle atrophy, and fatty infiltration via semiquantitative signal intensity analysis. In addition, re-defect patterns were evaluated. Results: The mean follow-up time in the SR group was 16.8 ± 4.6 months. The mean SSV was 91.0% ± 8.8%, mean CS was 82.2 ± 8.1 (contralateral side, 88.8 ± 5.3), and mean WORC score was 96.5% ± 3.2%. The mean follow-up time in the DR group was 23.4 ± 2.9 months, with patients achieving scores of 92.9% ± 9.6% for the SSV, 77.0 ± 8.6 for the CS (contralateral side, 76.7 ± 17.1), and 90.7% ± 12.6% for the WORC (P > .05). No significant differences were detected in the clinical outcome between groups. Tendon integrity was as follows. Type 1, none in either group; type 2, 4 SR and 5 DR; type 3, 9 SR and 10 DR; type 4, 3 SR and 3 DR; and type 5, 3 SR and 2 DR. The failure rate was 31.6% (n = 6) in the SR group and 25% (n = 5) in the DR group (P > .05). No significant differences were obtained for muscular atrophy or fatty degeneration (SR group, 0.94 ± 0.16; DR group, 1.15 ± 0.5) (P > .05). Re-defects revealed lateral cuff failure in 83.3% of SR patients in contrast to patients treated with DR techniques. The re-defect pattern was medial cuff failure in 80% of the patients. Conclusion: The clinical results after modified Mason-Allen single-row versus double-mattress suture bridge technique did not demonstrate significant differences in a matched patient cohort. Concerning the failure mode, single- and double-row techniques seem to demonstrate different re-defect patterns.

Single versus double-row repair of the rotator cuff

PurposeSeveral techniques for arthroscopic repair of rotator cuff defects have been introduced over the past years. Besides established techniques such as single-row repairs, new techniques such as double-row reconstructions have gained increasing interest. The present article therefore provides an overview of the currently available literature on both repair techniques with respect to several anatomical, biomechanical, clinical and structural endpoints.MethodsSystematic literature review of biomechanical, clinical and radiographic studies investigating or comparing single- and double-row techniques. These results were evaluated and compared to provide an overview on benefits and drawbacks of the respective repair type.ResultsReconstructions of the tendon-to-bone unit for full-thickness tears in either single- or double-row technique differ with respect to several endpoints. Double-row repair techniques provide more anatomical reconstructions of the footprint and superior initial biomechanical characteristics when compared to single-row repair. With regard to clinical results, no significant differences were found while radiological data suggest a better structural tendon integrity following double-row fixation.ConclusionPresently published clinical studies cannot emphasize a clearly superior technique at this time. Available biomechanical studies are in favour of double-row repair. Radiographic studies suggest a beneficial effect of double-row reconstruction on structural integrity of the reattached tendon or reduced recurrent defect rates, respectively.

Anterior glenoid rim defects of the shoulder

Bony instability of the shoulder due to glenoid defects has recently received increasing attention. Glenoid defects can be divided into acute fragment-type lesions (type I), chronic fragment-type lesions (type II) and glenoid bone loss without a bony fragment (type III). The diagnosis and classification are mainly based on imaging methods including a radiographic instability series and/or computed tomography. The management of anterior glenoid rim lesions depends on many factors including the clinical presentation, type of lesion, concomitant pathology as well as age and functional demands of the patient. If bony-mediated instability is present, surgery is indicated. In the majority of cases fragment-type lesions can be successfully treated using either arthroscopic or open reconstruction techniques.Small erosion-type lesions can also be managed via soft-tissue procedures, whereas large erosion-type lesions with significant bone loss may necessitate bone-grafting procedures (autologous iliac crest or coracoid transfer) to restore glenoid concavity and shoulder stability. Although glenoid bone grafting is usually performed via an open approach, recent clinical studies have shown that it can be successfully managed by advanced arthroscopic techniques.

Anteriore Glenoidranddefekte der Schulter

Bony instability of the shoulder due to glenoid defects has recently received increasing attention. Glenoid defects can be divided into acute fragment-type lesions (type I), chronic fragment-type lesions (type II) and glenoid bone loss without a bony fragment (type III). The diagnosis and classification are mainly based on imaging methods including a radiographic instability series and/or computed tomography. The management of anterior glenoid rim lesions depends on many factors including the clinical presentation, type of lesion, concomitant pathology as well as age and functional demands of the patient. If bony-mediated instability is present, surgery is indicated. In the majority of cases fragment-type lesions can be successfully treated using either arthroscopic or open reconstruction techniques.Small erosion-type lesions can also be managed via soft-tissue procedures, whereas large erosion-type lesions with significant bone loss may necessitate bone-grafting procedures (autologous iliac crest or coracoid transfer) to restore glenoid concavity and shoulder stability. Although glenoid bone grafting is usually performed via an open approach, recent clinical studies have shown that it can be successfully managed by advanced arthroscopic techniques.

Arthroscopic anatomic glenoid reconstruction using an autologous iliac crest bone grafting technique

BACKGROUND Open bone block procedures for glenohumeral stabilization have been used for a long time. With the advancement of arthroscopic techniques and the development of sophisticated instruments and implants, the insertion of the bone block can be performed by an all-arthroscopic approach. The purpose of this study was to evaluate the clinical and radiologic results after an arthroscopic anatomic glenoid reconstruction using an all-arthroscopic, autologous tricortical iliac crest bone grafting technique. MATERIALS AND METHODS Fifteen patients (1 female and 14 male patients; mean age, 31.4 years [range, 17-49 years]) underwent reconstruction of significant glenoid defects in cases of recurrent shoulder instability by the aforementioned technique. The patients were followed up clinically (range of motion, Constant score, Rowe score, Subjective Shoulder Value, and Western Ontario Shoulder Instability Index) and radiographically (with true anteroposterior and axillary views, as well as 2-/3-dimensional computed tomography [glenoid configuration, signs of graft resorption, bone consolidation, and glenoid index]). RESULTS After a mean follow-up period of 20.6 months (range, 12-65 months), the Constant score averaged 85.0 points (range, 73-98 points; contralateral side, 89.6 points [range, 78-96 points]), the Rowe score averaged 88.0 points (range, 65-100 points), the Subjective Shoulder Value averaged 84.5% (range, 50%-100%), and the Western Ontario Shoulder Instability Index averaged 76.7% (range, 46%-93%). No recurrent subluxations or dislocations were observed. Radiographically, computed tomography imaging showed a consolidated autograft in all cases. The glenoid index increased from a mean of 0.77 preoperatively to 1.16 immediately postoperatively; at the time of last follow-up, the glenoid index decreased to 1.04. CONCLUSION The arthroscopic reconstruction of anteroinferior glenoid defects re-creates the pear-shaped anatomy of the anteroinferior glenoid and leads to good to excellent early clinical results.

Arthroscopic stabilization of acute acromioclavicular joint dislocation

ZusammenfassungIn den letzten Jahren haben arthroskopische bzw. minimalinvasive Techniken zur Therapie von Schultereckgelenksprengungen zunehmend Verbreitung gefunden. Zum einen wurden etablierte Verfahren der offenen Chirurgie modifiziert und auf ein arthroskopisches Niveau angehoben. Zum anderen sind neue Implantate entwickelt worden, die es ermöglichen, rekonstruktive Techniken rein arthroskopisch unter Aufhebung der Nachteile der offenen Verfahren durchzuführen. Die bisher beschriebenen kurz- bis mittelfristigen Resultate dieser arthroskopischer Verfahren sind den offenen Verfahren hinsichtlich der klinischen und radiologischen Ergebnisse mindestens ebenbürtig.AbstractDuring the past few years arthroscopic and minimal invasive techniques for stabilization of acromioclavicular (AC) joint dislocations have gained increasing interest. Well established procedures for open surgery were modified and implemented to attain an arthroscopic level. Furthermore implants were developed which enable these reconstructive techniques to be performed arthroscopically without the disadvantages of open procedures. The short to mid-term results described so far concerning the clinical and radiological outcome of arthroscopic stabilization techniques show an at least equal outcome to those presented in open surgery.During the past few years arthroscopic and minimal invasive techniques for stabilization of acromioclavicular (AC) joint dislocations have gained increasing interest. Well established procedures for open surgery were modified and implemented to attain an arthroscopic level. Furthermore implants were developed which enable these reconstructive techniques to be performed arthroscopically without the disadvantages of open procedures. The short to mid-term results described so far concerning the clinical and radiological outcome of arthroscopic stabilization techniques show an at least equal outcome to those presented in open surgery.

Arthroskopische Stabilisierung der akuten Schultereckgelenksprengung

ZusammenfassungIn den letzten Jahren haben arthroskopische bzw. minimalinvasive Techniken zur Therapie von Schultereckgelenksprengungen zunehmend Verbreitung gefunden. Zum einen wurden etablierte Verfahren der offenen Chirurgie modifiziert und auf ein arthroskopisches Niveau angehoben. Zum anderen sind neue Implantate entwickelt worden, die es ermöglichen, rekonstruktive Techniken rein arthroskopisch unter Aufhebung der Nachteile der offenen Verfahren durchzuführen. Die bisher beschriebenen kurz- bis mittelfristigen Resultate dieser arthroskopischer Verfahren sind den offenen Verfahren hinsichtlich der klinischen und radiologischen Ergebnisse mindestens ebenbürtig.AbstractDuring the past few years arthroscopic and minimal invasive techniques for stabilization of acromioclavicular (AC) joint dislocations have gained increasing interest. Well established procedures for open surgery were modified and implemented to attain an arthroscopic level. Furthermore implants were developed which enable these reconstructive techniques to be performed arthroscopically without the disadvantages of open procedures. The short to mid-term results described so far concerning the clinical and radiological outcome of arthroscopic stabilization techniques show an at least equal outcome to those presented in open surgery.During the past few years arthroscopic and minimal invasive techniques for stabilization of acromioclavicular (AC) joint dislocations have gained increasing interest. Well established procedures for open surgery were modified and implemented to attain an arthroscopic level. Furthermore implants were developed which enable these reconstructive techniques to be performed arthroscopically without the disadvantages of open procedures. The short to mid-term results described so far concerning the clinical and radiological outcome of arthroscopic stabilization techniques show an at least equal outcome to those presented in open surgery.

Characteristics and Stimulation Potential with BMP-2 and BMP-7 of Tenocyte-Like Cells Isolated from the Rotator Cuff of Female Donors

Tendon bone healing of the rotator cuff is often associated with non-healing or recurrent defects, which seems to be influenced by the patient’s age and sex. The present study aims to examine cellular biological characteristics of tenocyte-like cells that may contribute to this impaired rotator cuff healing. Moreover, a therapeutic approach using growth factors could possibly stimulate tendon bone healing. Therefore, our second aim was to identify patient groups who would particularly benefit from growth factor stimulation. Tenocyte-like cells isolated from supraspinatus tendons of female donors younger and older than 65 years of age were characterized with respect to different cellular biological parameters, such as cell density, cell count, marker expression, collagen-I protein synthesis, and stem cell potential. Furthermore, cells of the donor groups were stimulated with BMP-2 and BMP-7 (200 and 1000 ng/ml) in 3D-culture and analyzed for cell count, marker expression and collagen-I protein synthesis. Female donors older than 65 years of age showed significantly decreased cell count and collagen-I protein synthesis compared to cells from donors younger than 65 years. Cellular biological parameters including cell count, collagen-I and –III expression, and collagen-I protein synthesis of cells from both donor groups were stimulated with BMP-2 and BMP-7. The cells from donors older than 65 years revealed a decreased stimulation potential for cell count compared to the younger group. Cells from female donors older than 65 years of age showed inferior cellular biological characteristics. This may be one reason for a weaker healing potential observed in older female patients and should be taken into consideration for tendon bone healing of the rotator cuff.