Publications by authors named "Kai-Axel Witt"

14 Publications

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Treating cuff tear arthropathy by reverse total shoulder arthroplasty: do the inclination of the humeral component and the lateral offset of the glenosphere influence the clinical and the radiological outcome?

Eur J Orthop Surg Traumatol 2021 Apr 20. Epub 2021 Apr 20.

Orthopedic Practice Clinic (OPPK), Schuerbusch 55, 48143, Münster, Germany.

Purpose: Reverse total shoulder arthroplasty is widely used for the treatment of cuff tear arthropathy. Standard implants consist of a humeral component with an inclination angle of 155° and a glenosphere without lateral offset. Recently, lower inclination angles of the humeral component as well as lateralized glenospheres are implanted to provide better rotation of the arm and to decrease the rate of scapular notching. This study investigates the clinical and radiological results of a standard reverse total shoulder in comparison with an implant with an inclination angle of 135° in combination with a 4 mm lateralized glenosphere in context of cuff tear arthropathy.

Material And Methods: For this retrospective comparative analysis 42 patients treated by reverse total shoulder arthroplasty for cuff tear arthropathy were included. Twenty-one patients (m = 11, f = 10; mean age 76 years; mean follow-up 42 months) were treated with a standard 155° humeral component and a standard glenosphere with caudal eccentricity (group A), while twenty-one patients (m = 5, f = 16; mean age 72 years; mean follow-up 34 months) were treated with a 135° humeral component and 4 mm lateral offset of the glenosphere (group B). At follow-up patients of both groups were assessed with plain X-rays (a.p. and axial view), Constant Score, adjusted Constant Score, the subjective shoulder value and the range of motion.

Results: The clinical results were similar in both groups concerning the Constant Score (group A = 56.3 vs. group B = 56.1; p = 0.733), the adjusted CS (group A = 70.4% vs. group B = 68.3%; p = 0.589) and the SSV (group A = 72.0% vs. group B = 75.2%; p = 0.947). The range of motion of the operated shoulders did not differ significantly between group A and group B: Abduction = 98° versus 97.9°, p = 0.655; external rotation with the arm at side = 17.9° versus 18.7°, p = 0.703; external rotation with the arm positioned in 90° of abduction = 22.3° versus 24.7°, p = 0.524; forward flexion = 116.1° versus 116.7°, p = 0.760. The rate of scapular notching was higher (p = 0.013) in group A (overall: 66%, grade 1: 29%, grade 2: 29%, grade 3: 10%, grade 4: 0%) in comparison to group B (overall: 33%, grade 1: 33%, grade 2: 0%, grade 3: 0%, grade 4: 0%). Radiolucency around the humeral component was detected in two patients of group B. Stress shielding at the proximal humerus was observed in six patients of Group A (29%; cortical thinning and osteopenia in zone M1 and L1) and two patients of group B (10%; cortical thinning and osteopenia in zone M1 and L1). Calcifications of the triceps origin were observed in both groups (group A = 48% vs. group B = 38%).

Conclusion: Theoretically, a lower inclination angle of the humeral component and an increased lateral offset of the glenosphere lead to improved impingement-free range of motion and a decreased rate of scapular notching, when compared to a standard reverse total shoulder implant. This study compared two different designs of numerous options concerning the humeral component and the glenosphere. In comparison to a standard-fashioned implant with a humeral inclination of 155° and a standard glenosphere, implants with a humeral inclination angle of 135° and a 4 mm lateralized glenosphere lead to comparable clinical results and rotatory function, while the rate of scapular notching is decreased by almost 50%. While the different implant designs did not affect the clinical outcome, our results indicate that a combination of a lower inclination angle of the humeral component and lateralized glenosphere should be favored to reduce scapular notching.

Level Of Evidence: Level III, retrospective comparative study.
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http://dx.doi.org/10.1007/s00590-021-02976-4DOI Listing
April 2021

Arthroscopic and open partial arthroplasty for the treatment of focal grade IV cartilage defects of the humeral head.

Arch Orthop Trauma Surg 2020 Jul 26. Epub 2020 Jul 26.

Orthopedic Practice Clinic (OPPK), Munster, Germany.

Introduction: Focal Outerbridge grade IV cartilage defects of the proximal humerus may lead to pain and an impaired shoulder function. In cases of failed operative or conservative treatment options such as intraarticular injections or arthroscopic microfracturing of the subchondral bone, partial arthroplasty of the humeral may restore the articular surface of the humeral head without altering the anatomy. This study evaluates mid-term results of open and arthroscopic partial resurfacing of the humeral head in the context of focal grade IV cartilage defects.

Methods: Eighteen patients (f = 3, m = 15, mean age = 57.7 years) out of 22 patients were available for follow-up after 65 (24-116) months. Thirteen patients were treated with a partial humeral head prosthesis in an open technique and five patients received a partial humeral head prosthesis in an arthroscopic technique. The patients were followed-up clinically using the Constant-Score, the ASES Score as well as the range of motion. Plain radiographs (anterior-posterior and axial view) were carried out for radiologic assessment.

Results: At follow-up the mean CS rated 79.5. The mean ASES Score was 85.8 points. Mean active forward flexion measured 163.8°, while mean active abduction was 160.0°. The average pain level on a visual analogue scale (VAS) made out 0.7 out of 10. Patients treated with an arthroscopically implanted prosthesis achieved a mean CS of 88.8 points and a mean ASES Score of 92.6 points. The patients with openly implanted prosthesis had a CS of 75.3 points and an ASES Score of 83 points. There were no intraoperative or immediate postoperative complications. Until the final follow-up one patient needed to be converted to total shoulder arthroplasty due to progressive glenohumeral osteoarthritis. Nine patients (50%) showed progressive glenohumeral osteoarthritis. Aseptic loosening of the implants was not observed.

Conclusion: Partial arthroscopic or open arthroplasty of the humeral head is related to good functional results after mid-term follow-up. Resurfacing of the humeral head is a safe procedure without any implant-related complications. There is a risk for progression of glenohumeral osteoarthritis, which may require surgical revision with conversion to anatomic shoulder arthroplasty.

Level Of Evidence: Level IV (retrospective study).
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http://dx.doi.org/10.1007/s00402-020-03552-xDOI Listing
July 2020

[Arthroscopically-assisted treatment of acute and chronic dislocations of the acromioclavicular joint : A prospective clinical trial].

Orthopade 2021 Mar;50(3):214-223

Orthopädische Praxisklinik Münster, Münster, Deutschland.

Background: Injuries of the acromioclavicular joint (ACJ) are frequent and often occur during sports. While arthroscopically-assisted stabilization of acute injuries of the ACJ is a well-established procedure, there is not much data available for arthroscopically-assisted stabilization of chronic injuries of the ACJ.

Objectives: This study assesses clinical and radiological results of arthroscopically-assisted stabilization of acute and chronic injuries of the ACJ.

Materials And Methods: Thirty-six patients with acute and chronic injuries of the ACJ were assessed in a prospective clinical trial. Twenty-five patients with acute injuries (group A) and eleven patients with chronic injuries (group B) were included in this study. Patients of group A were operated using two suture-button systems, while patients of group B received one suture-button system and an autologous gracilis tendon graft.

Results: In group A, the mean preoperative Constant score rated 38, and the ASES score rated 34. At follow-up the Constant score (92) and the ASES score (89) had improved. Panorama views revealed an increased coracoclavicular distance of the affected shoulder (15.8 mm) in comparison to the contralateral shoulder (10.9 mm). In group B, the preoperative Constant score measured 57. It improved to 72 points at follow-up. The ASES score improved from 39 to 72 points in the same period. Panorama views revealed an increased coracoclavicular distance of the affected shoulder (18.9 mm) in comparison to the contralateral shoulder (12.4 mm).

Conclusions: Stabilization of acute injuries of the ACJ with two suture-button systems is related to very good shoulder function after one year. The native coracoclavicular distance cannot be restored with this procedure. Stabilization of chronic injuries of the ACJ with a suture-button system and an autologous gracilis tendon graft is related to improved shoulder function after one year. However, shoulder function cannot be fully restored with the stabilization technique presented.
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http://dx.doi.org/10.1007/s00132-020-03914-8DOI Listing
March 2021

Traumatic Tear of the Latissimus Dorsi Tendon in a CrossFit Athlete: Surgical Management.

J Orthop Case Rep 2019 ;9(5):82-86

Department of Orthopaedic Surgery, Orthopaedic Practice Clinic, Von-Vincke-Str. 14, 48143 Münster, Germany.

Introduction: Traumatic tears of the latissimus dorsi tendon (LDT) are a rare sports injury that may occur during exercises involving horizontal and vertical pulling. A standardized treatment algorithm for this injury does not yet exist.

Case Report: A 30-year old male CrossFit Athlete experienced sudden unbearable pain in his right posterior shoulder during a bar muscle-up exercise. The contour of his right posterior shoulder had changed immediately, and the patient could not do any more exercises involving his right shoulder. BMagnet resonance imaging (MRI) revealed an isolated tear of the LDT. The repair of the tendon was performed using a posterior approach in the lateral decubitus position. After arming the tendon with non-absorbable sutures it was reinserted onto the crest of the lesser tuberosity of the proximal humerus with two monocortical suture buttons. Postoperatively, the patient was immobilized with an abduction pillow for 6 weeks. After 9 months he reported a 90% function of his shoulder. MRI showed complete anatomical reinsertion of the LDT. The patient was able to master 15 pull-ups in a row.

Conclusions: Surgical repair of the LDT may achieve good functional results as well as an acceptable recovery period.
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http://dx.doi.org/10.13107/jocr.2250-0685.1546DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276628PMC
January 2019

Bilateral stemless shoulder hemiarthroplasty in a female patient suffering from pseudoachondroplasia: A case report.

J Orthop Sci 2018 Oct 11. Epub 2018 Oct 11.

Orthopedic Practice Clinic (OPPK), Münster, Germany.

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http://dx.doi.org/10.1016/j.jos.2018.09.014DOI Listing
October 2018

All-Extra-articular Repair of Anterosuperior Rotator Cuff Tears.

Arthrosc Tech 2018 Feb 1;7(2):e83-e88. Epub 2018 Jan 1.

Orthopedic Practice Clinic (OPPK), Münster, Germany.

Anterosuperior rotator cuff tears involve the subscapularis tendon, supraspinatus tendon, and rotator interval. The long head of the biceps is usually affected and unstable in these complex lesions. Arthroscopic repair of anterosuperior rotator cuff tears often consists of 2 different procedures. Whereas the subscapularis tendon is reconstructed under intra-articular visualization, the supraspinatus tendon is reconstructed under extra-articular visualization. The rotator interval is often sacrificed to improve visualization and instrumentation. The presented technique uses an all-extra-articular approach, which helps to reconstruct these complex rotator cuff lesions in their whole extent without switching from the inside to the outside of the shoulder joint. The preservation of the rotator interval leads to a more stable and anatomic reconstruction.
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http://dx.doi.org/10.1016/j.eats.2017.08.056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5851895PMC
February 2018

Conversions from anatomic shoulder replacements to reverse total shoulder arthroplasty: do the indications for initial surgery influence the clinical outcome after revision surgery?

Arch Orthop Trauma Surg 2017 Feb 17;137(2):167-172. Epub 2016 Nov 17.

Orthopedic Practice Clinic (OPPK), Schürbusch 55, 48143, Münster, Germany.

Introduction: The most frequent indications for anatomic shoulder replacement are glenohumeral osteoarthritis and fractures of the humeral head. If anatomic shoulder prostheses fail, reverse total shoulder arthroplasty is often the only remaining treatment option. This study evaluates the influence of indications for primary shoulder arthroplasty on the clinical outcome after conversion to reverse total shoulder arthroplasty.

Materials And Methods: From 2010 to 2012, 44 failed shoulder arthroplasties were converted to reverse total shoulder arthroplasty. Forty-four patients were available for follow-up after a mean of 24 months (14-36 months). Twenty-three of them had received an initial shoulder replacement because of osteoarthritis, while the remaining 21 patients had been treated for a fracture of the humeral head. At follow-up, patients were assessed with X-rays, constant-, and ASES scores.

Results: The total number of observed complications was higher in patients revised because of failed fracture arthroplasty (24 vs. 9%). Patients initially treated for osteoarthritis achieved a higher ASES score (71 vs. 59 points; p = 0.048). The normalized constant score was not different between the two observed groups (osteoarthritis 73% vs. fracture 67%: p = 0.45). Complications occurred more often in patients who had initially suffered from a fracture of the humeral head (fracture 23.8% vs. osteoarthritis 8.7%). Scapular notching was more frequent after initial fracture arthroplasty (33 vs. 14%).

Conclusion: Indications for initial shoulder replacement have an influence on the clinical outcome after conversion to reverse total shoulder arthroplasty. Patients initially treated for a fracture of the humeral head have a lower subjective outcome and a higher complication rate in comparison with patients initially treated for osteoarthritis.

Level Of Evidence: IV (Retrospective study).
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http://dx.doi.org/10.1007/s00402-016-2595-5DOI Listing
February 2017

Outcome after failed traumatic anterior shoulder instability repair with and without surgical revision.

J Shoulder Elbow Surg 2007 Nov-Dec;16(6):742-7. Epub 2007 Oct 29.

Department of Orthopaedics, University Hospital of Münster, Münster, Germany.

The purpose of this study was to evaluate the incidence and reasons of recurrent instability in patients with traumatic anterior shoulder instability and to document the clinical results with regard to the number of stabilizing procedures. Twenty-four patients with failed primary open or arthroscopic anterior shoulder stabilization were followed for a mean of 68 (36-114) months. Following recurrence of shoulder instability, eight patients chose not to be operated on again, whereas 16 underwent repeat stabilization. A persistent or recurrent Bankart lesion was found in all 16 patients and concomitant capsular redundancy in 4. After the first revision surgery, further instability occurred in 8 patients, and 6 of them were stabilized a third time. Only 7 patients (29%) achieved a good or excellent result according to the Rowe score. All shoulder scores improved after revision stabilization. However, the number of stabilizing procedures adversely affected the outcome scores, as well as postoperative range of motion and patient satisfaction. Recurrent instability after a primary stabilization procedure represents a difficult diagnostic and surgical challenge, and careful attention should be paid to address persistent or recurrent Bankart lesions and concomitant capsular reduncancy. A satisfying functional outcome can be expected mainly in patients with one revision surgery. Further stabilization attempts are associated with poorer objective and subjective results.
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http://dx.doi.org/10.1016/j.jse.2007.02.132DOI Listing
January 2008

Arthroscopic Bankart repair in traumatic anterior shoulder instability using a suture anchor technique.

Arthroscopy 2006 Sep;22(9):931-6

Department of Orthopaedics, University Hospital of Münster, Münster, Germany.

Purpose: The purpose of this study was to prospectively evaluate the surgical outcome of arthroscopic Bankart repair via suture anchors in patients with recurrent traumatic anterior shoulder instability with a minimum follow-up of 2 years.

Methods: We included 54 consecutive patients without an osseous Bankart lesion of greater than 25% of the glenoid circumference with a mean age of 25.3 years (range, 16 to 58 years) undergoing arthroscopic Bankart repair via suture anchors for traumatic anterior shoulder instability. The mean follow-up was 3.7 years (range, 2.3 to 5.2 years) at the final follow-up examination. Patients were evaluated prospectively according to the rating scales of Rowe, the American Shoulder and Elbow Surgeons, and Constant and Murley. One patient was lost to follow-up.

Results: After 3.7 years, 4 patients had recurrent instability: 3 had redislocated and 1 had recurrent subluxations. Thus the overall redislocation rate was 7.5%. Of the 4 redislocators, 3 had a traumatic onset of the redislocation. All shoulder scores (Rowe, American Shoulder and Elbow Surgeons, and Constant and Murley) revealed highly significant improvements postoperatively. At final follow-up, 85.7% of patients had returned to their preoperative sports level.

Conclusions: Our results in this series demonstrate the efficacy of arthroscopic Bankart repair with suture anchors for the treatment of recurrent traumatic anterior shoulder instability with respect to recurrence rate, range of motion, and shoulder function during a mean follow-up of 3.7 years.

Level Of Evidence: Level IV, therapeutic case series.
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http://dx.doi.org/10.1016/j.arthro.2006.04.105DOI Listing
September 2006

Long-term results of arthroscopic Bankart repair with a bioabsorbable tack.

Am J Sports Med 2006 Dec 10;34(12):1906-10. Epub 2006 Aug 10.

Department of Orthopaedics, University Hospital of Münster, Albert-Schweitzer Str 33, 48129 Münster, Germany.

Background: Short-term to midterm data are available on arthroscopic shoulder stabilization using bioabsorbable tacks or suture anchors. It remains unknown whether these techniques can equal the success of open Bankart repair in the long term.

Purpose: To assess the long-term outcome of arthroscopic Bankart repair using bioabsorbable tacks in patients with traumatic anterior shoulder instability with a minimum follow-up of 7 years.

Study Design: Case series; Level of evidence, 4.

Methods: Treatment outcomes were determined prospectively according to the Rowe score and retrospectively according to the Constant and American Shoulder and Elbow Surgeons scores. Included in this study were 18 consecutive patients with a mean age of 26.8 years (range, 16-62 years) who underwent arthroscopic Bankart repair using bioabsorbable tacks for traumatic anterior shoulder instability. The study group consisted of 14 male and 4 female patients. The mean follow-up was 8.7 years (range, 7.0-9.8 years).

Results: One patient had recurrent dislocations requiring further surgery, for an overall failure rate of 5.6%. An additional patient had 1 traumatic subluxation episode within the first postoperative year that did not recur. According to the Rowe score, which increased to 90.3 (17.8) from 32.8 (8.3) points preoperatively, 15 patients (83.3%) achieved a good or excellent result. The mean Constant score was 91.3 (SD, 6.9) points, and the mean American Shoulder and Elbow Surgeons score was 92.1 (SD, 6.9) points postoperatively. A return to the preinjury level of sports competition was reported by 64% of patients. No signs of synovitis occurred in any patient postoperatively.

Conclusion: Arthroscopic Bankart repair for the treatment of recurrent traumatic anterior shoulder instability repair using bioabsorbable tacks offers reliable results with respect to failure rate, range of motion, and shoulder function during a minimum follow-up of 7.0 years. In contrast to previous reports on arthroscopic Bankart repair, results did not deteriorate during follow-up.
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http://dx.doi.org/10.1177/0363546506290404DOI Listing
December 2006

Quantitative assessment of glenohumeral translation after anterior shoulder dislocation and subsequent arthroscopic bankart repair.

Am J Sports Med 2006 Nov 13;34(11):1756-62. Epub 2006 Jul 13.

Department of Orthopaedics, University Hospital of Münster, Albert-Schweitzer Strasse 33, 48149 Münster, Germany.

Background: During the past decade, developments in arthroscopic technology have made arthroscopic repair of labral lesions feasible. However, results with the use of the transglenoid suture technique, or with the use of bioabsorbable tacks, have remained variable in the literature, and the recurrence rates are still inferior to those of open Bankart repair.

Hypothesis: Arthroscopic Bankart repair with suture anchors can re-create translational and rotational range of motion of the intact glenohumeral joint, and the number of preoperative dislocations has an influence on the result.

Study Design: Controlled laboratory study.

Materials: Twelve cadaveric shoulders were tested in a robot-assisted shoulder simulator. Anterior and posterior translation and external rotation were measured for intact, dislocated (shoulders were randomly selected to 1 of 3 groups, which were dislocated 1, 3, or 7 times), and repaired conditions at 0 degrees and 90 degrees of glenohumeral elevation.

Results: After shoulder dislocation, a significant increase was found in translation and rotation, confirming the creation of a traumatic shoulder instability model. Further testing of the specimen revealed that translational and rotational ranges of motion were reduced by arthroscopic Bankart repair at both testing positions. External rotation was decreased significantly at 0 degrees and 90 degrees of abduction. No significant differences were found between the 3 dislocation groups.

Conclusion: The results demonstrate a sufficient biomechanical performance of arthroscopic Bankart repair using suture anchors in a traumatic anterior shoulder instability model. With the numbers available, no relationship was found between the number of dislocations and the postoperative result concerning translational or rotational motion.

Clinical Relevance: Glenohumeral translation and rotation after arthroscopic Bankart repair with use of suture anchors approached near normal values, confirming the clinical success of this technique.
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http://dx.doi.org/10.1177/0363546506289702DOI Listing
November 2006

The influence of arthroscopic subscapularis tendon and anterior capsular release on glenohumeral translation: a biomechanical model.

J Shoulder Elbow Surg 2006 Jul-Aug;15(4):502-8

Department of Orthopaedics, University Hospital of Münster, Münster, Germany.

The effect of an arthroscopic release of the intraarticular portion of the subscapularis tendon and the anterior capsule on glenohumeral translation was investigated in a cadaveric model. Ten human cadaveric shoulders with a mean age of 63.5 years (range, 52-79 years) were tested in a robot-assisted shoulder simulator. Joint translation was measured before and after an arthroscopic release of the intraarticular portion of the subscapularis tendon and a subsequent release of the anterior capsule at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of glenohumeral elevation. Translation was measured in the anterior, anterior-inferior, and inferior directions under 20 N of applied load. Testing of the specimen revealed that the release of the intraarticular portion of the subscapularis tendon and the anterior capsule increased translation in all directions. Significant increases in translation were observed after release of the intraarticular portion of the subscapularis tendon in the midrange of motion. The influence of the arthroscopic capsular release, in conjunction with the release of the subscapularis tendon, was very high above 60 degrees of elevation. The study indicates that the intraarticular component of the subscapularis tendon functions as a restraint to anterior-inferior translation primarily in the midrange of glenohumeral motion, whereas the anterior capsule adds anterior-inferior stability to the glenohumeral joint mainly above 60 degrees of elevation.
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http://dx.doi.org/10.1016/j.jse.2005.09.018DOI Listing
January 2007

A modified capsular shift for atraumatic anterior-inferior shoulder instability.

Am J Sports Med 2005 Jul;33(7):1011-5

Department of Orthopaedics, University Hospital of Muenster, Albert-Schweitzer Str.33, 48149 Münster, Germany.

Purpose: To evaluate the long-term outcome of a modified inferior capsular shift procedure in patients with atraumatic anterior-inferior shoulder instability by analyzing a consecutive series of patients who had undergone a modified inferior capsular shift for this specific type of shoulder instability.

Study Design: Case series; Level of evidence, 4.

Methods: Between 1992 and 1997, 38 shoulders of 35 patients with atraumatic anterior-inferior shoulder instability that were unresponsive to nonoperative management were operated on using a modified capsular shift procedure with longitudinal incision of the capsule medially and a bony fixation of the inferior flap to the glenoid and labrum in the 1 o'clock to 3 o'clock position. The patient study group consisted of 9 men and 26 women with a mean age of 25.4 years (range, 15-55 years) at the time of surgery. The mean follow-up was 7.4 years (range, 4.0-11.4 years); 1 patient was lost to follow-up directly after surgery. The study group was evaluated according to the Rowe score.

Results: After 7.4 years, 2 patients experienced a single redislocation or resubluxation, 1 patient had recurrent dislocations, and 1 patient had a positive apprehension sign, which is an overall redislocation rate of 10.5%. The average Rowe score increased to 90.6 (SD = 19.7) points from 36.2 (SD = 13.5) points before surgery. Seventy-two percent of the patients participating in sports returned to their preoperative level of competition.

Conclusions: Results in this series demonstrate the efficacy and durability of a modified capsular shift procedure for the treatment of atraumatic anterior-inferior shoulder instability.
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http://dx.doi.org/10.1177/0363546504272685DOI Listing
July 2005

Influence of postoperative immobilization on tendon length after radiofrequency-induced shrinkage. An in vivo rabbit study.

Am J Sports Med 2003 Jan-Feb;31(1):36-40

Department of Orthopaedic Surgery, University Hospital Münster, Münster, Germany.

Background: Despite the widespread use of radiofrequency-induced shrinkage of collagenous tissues, there have been no animal studies on the effects of postoperative immobilization after such treatment.

Purpose: To examine the effects of postoperative immobilization after radiofrequency energy treatment, with special emphasis on any tissue length increases.

Study Design: Controlled laboratory study.

Methods: The right patellar tendon of 60 New Zealand White rabbits was shrunk with a radiofrequency probe. Tendon length was measured intraoperatively before and after shrinkage and via radiographs immediately postoperatively and at 3, 6, and 9 weeks. Twenty rabbits were not immobilized, 20 were immobilized for 3 weeks, and 20 were immobilized for 6 weeks.

Results: In the nonimmobilized limbs, the tendon length increased 34.9% at 3 weeks and another 2.5% at 6 weeks, versus 11.2% at 3 weeks and 6.6% at 6 weeks in the immobilized limbs. Ten of the 20 rabbits that were immobilized for 6 weeks were sacrificed at 9 weeks and were found to have a further length increase of 10.8%. At 9 weeks, the tendons of this group were no longer significantly shorter than the tendons from rabbits that had not been immobilized.

Conclusions: Careful postoperative rehabilitation is imperative after radiofrequency-induced shrinkage. Without protection, exposure to normal physiologic loads places the shrunken tissue at risk of stretching out beyond the preshrinkage length.

Clinical Relevance: Shrunken tissue is at risk of stretching out after radiofrequency-induced shrinkage.
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http://dx.doi.org/10.1177/03635465030310011701DOI Listing
April 2003