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The influence of medial reattachment of the torn cuff tendon for retracted rotator cuff tears
The influence of medial reattachment of the torn cuff tendon for retracted rotator cuff tears Hiroshi Takeda, MD,a Setsuo Urata, MD,b Masaaki Matsuura, PhD,c Akira Nakayama, PT,a and Hiroyuki Yonemitsu, MD,a Kumamoto and Tokyo, Japan
We reattached the torn rotator cuff medial to the anatomic cuff insertion site if it was retracted. The purpose was to correlate the amount of medial reattachment of the cuff with shoulder function. We evaluated 63 shoulders in which repaired cuffs were followed with magnetic resonance imaging at a mean follow-up of 8 years. The amount of medial reattachment of the cuff tendon was determined by use of a T2-weighted oblique coronal view, which passed through the center of the humeral head, and was defined as the NCA angle (where N indicates the new cuff insertion point, C indicates the center of the humeral head, and A indicates the anatomic cuff insertion point). Theoretically, the more medially the cuff tendon was reattached, the greater the NCA angle. Neither the Japanese Orthopaedic Association shoulder score nor isometric strength of forward elevation was correlated with the NCA angle. The NCA angle was significantly correlated (P ⫽ .001) with the active forward elevation angle, which dramatically decreased at 30° of the NCA angle, approximately 13 mm from the original cuff insertion point, assuming a humeral head radius of 25 mm. (J Shoulder Elbow Surg 2007;16:316-320.)
T he repair of the rotator cuff is an effective method of reducing shoulder pain and restoring shoulder function. In cases in which a torn cuff is retracted, reattaching the cuff medial to the anatomic cuff insertion site is an option. By doing so, tension at the repair site can be reduced; on the other hand, the length of the moment arm of the reinserted cuff decreases, and this may weaken shoulder strength or decrease the range of motion. Although reattaching the torn cuff tendon
From the aDepartment of Orthopaedics, Kumamoto Kinoh Hospital, and bAsouda Seikeigeka Clinic, Kumamoto, and cDepartment of Physics, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo. Reprint requests: Hiroshi Takeda, MD, Department of Orthopaedics, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kumamoto-City, Kumamoto 860-8518, Japan (E-mail: [email protected]) Copyright © 2007 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2007/$32.00 doi:10.1016/j.jse.2006.10.001
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medial to the anatomic cuff insertion site is a common option for repairing retracted cuffs,6,12-15 there have been no clinical studies regarding the influence of medial reattachment of the cuff. We quantified the amount of medial reattachment of the torn cuff tendon trigonometrically, by use of magnetic resonance imaging (MRI), at the time of follow-up so that we could analyze the correlation of the amount of medial reattachment of cuff insertion with shoulder function. The purpose of this study was to test our hypothesis that medial reattachment of the cuff tendon influences shoulder function. To our knowledge, this is the first clinical study analyzing the effects of medial reattachment of torn cuff tendons. MATERIALS AND METHODS There were 274 open rotator cuff repairs performed at our institution from January 1989 to December 1996. When rotator cuff repair was performed, the torn cuff tendons were reattached to the site to which the cuff could reach without excessive tension, with the arm at the side. Therefore, a torn cuff tendon was reattached medial to the anatomic cuff insertion site if it was retracted. Seventy patients (seventy-six shoulders) were able to return for the long-term follow-up (ⱖ5 years). The rest of the patients could not return for this long-term follow-up because of geographic or mobility issues. MRI examinations were performed on every patient (Philips GyroScan T5-II, 0.5 T; Philips Medical Systems, Best, The Netherlands). MRI findings were determined by a radiologist who was not informed about the patients’ profiles. A high-intensity area on the T2-weighted oblique coronal view of the cuff was regarded as indicating a detached cuff. The amount of medial reattachment of the cuff tendon was determined by use of a T2-weighted oblique coronal view, which passed through the center of the humeral head, and was defined as the NCA angle (where N indicates the new cuff insertion point, C indicates the center of the humeral head, and A indicates the normal cuff insertion point) (Figure 1). The center of the humeral head (point C) was determined geometrically and checked with circular templates. The newly created cuff insertion point (point N) was determined as the most medial border of the reinserted cuff tendon. The normal cuff insertion point (point A) is the most medial insertion point of the supraspinatus tendon. In shoulders without chronic rotator cuff tears, this point is easily determined as the step-off of the greater tuberosity. However, in shoulders with large or chronic rotator cuff tears, the greater tuberosity becomes
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Isometric shoulder strength was measured with a MicroFET handheld dynamometer (Hoggan Health Industries, West Jordan, UT). Isometric strength of forward elevation was measured with the arm held at 90° of elevation in the scapular plane. Isometric strength of external rotation and internal rotation was measured with the arm at the side with 0° of rotation. The measurements were repeated 3 times, and the mean was used for statistical analysis. When analyzing isometric shoulder strength, we used the ratios of isometric strength of the operative shoulders to that of the contralateral shoulders, which were asymptomatic. Active shoulder range of motion was measured with a goniometer. Internal rotation was determined as the highest spine level to which the extended thumb could reach.
Surgical technique Figure 1 Amount of medialization of cuff attachment. The amount of medial reattachment of the cuff tendon was defined by use of a T2-weighted oblique coronal view as the NCA angle (N, new cuff insertion point; C, center of humeral head; A, normal cuff insertion point).
flat and round, and the anatomic supraspinatus insertion point is difficult to determine. In this situation, the anatomic supraspinatus insertion point (point A) was determined based on the assumption that the total arc of the articular surface (ICA angle [where I indicates the inferior margin of the articular surface, C indicates the center of the humeral head, and A indicates the normal cuff insertion point]) in the frontal plane is 150°, which has been reported as the mean of the normal population.8,9,17 To investigate the influence of medial reattachment of the cuff tendon, we analyzed shoulders that had successfully reattached cuffs. Among the initial 76 shoulders, 9 had retears of the cuffs and 4 had developed severe osteoarthritis after surgery; we excluded these 13 shoulders, leaving 63 shoulders for analysis. There were 46 men and 17 women. The mean age at the time of surgery was 52 ⫾ 10 years (range, 32-73 years). The mean age at follow-up was 60 ⫾ 10 years (range, 41-81 years). The mean duration of follow-up was 8 years 2 months (SD, 2 years; range, 5 years 1 month to 12 years 6 months). The sizes of the tears in the 63 shoulders at surgery were determined by use of the classification of Cofield and Lanzer.2 There were 11 partialthickness tears (18.4%), 10 small-sized tears (⬍1 cm) (13.2%), 15 medium-sized tears (1-3 cm) (21.1%), 25 large-sized tears (3-5 cm) (42.1%), and 2 massive tears (⬎5 cm) (5.3%). Clinical outcomes were evaluated by use of the Japanese Orthopaedic Association (JOA) shoulder scoring system. This system is based on a total of 100 points, with 30 points for pain, 20 points for function, 30 points for range of motion, 5 points for radiographic change, and 15 points for joint stability (Table I). Isometric shoulder strength (forward elevation, external rotation with the arm at the side, and internal rotation with the arm at the side) and active shoulder range of motion (forward elevation, external rotation with the arm at the side, and internal rotation behind the back) were measured by the same observer, who was blinded to the patients’ profiles.
Under general anesthesia, the patient was placed on the operating table in the beach-chair position. All of the operations were performed by one of the authors. After an anterolateral skin incision was made, the deltoid muscle was split 4 cm from the acromioclavicular joint. The deltoid origin was detached no more than 5 mm from the acromion. The coracoacromial ligament and the subacromial bursa were resected. An anterior acromioplasty was performed for all shoulders. External and internal cuff mobilization, including release of the humeroscapular interface, a relaxing incision to the cuff, cutting of the coracohumeral ligament, and release of the capsule just lateral to the superior glenoid, was performed as necessary. A bone trough was created at a site at which the cuff could reattach without creating excessive tension at the repair site, with the arm at the side. Partial-thickness tears were treated by excising the damaged areas and repairing them in the same manner as described previously. If there was lamination of the cuff, mattress sutures were placed between the superficial layers and the deep layers. Passive range-of-motion exercises were started a few days after surgery, and active range-of-motion exercises were allowed after 5 weeks. Nonsteroidal anti-inflammatory medicines were used for all patients postoperatively. Strenuous activities with the operative shoulder were not allowed for 6 months.
Statistical analysis Statistical analysis was done by use of the SPSS software package (version 11.0; SPSS, Chicago, Ill). The MannWhitney U test was used to compare the 2 unpaired groups. For paired groups of 2, the Wilcoxon signed rank test was performed. To compare more than 3 groups, the Kruskal-Wallis test was used. P ⬍ .05 was considered significant. For multiple comparisons, according to the Bonferroni adjustment procedures, ␣* (␣* ⫽ ␣/k, where k indicates the number of the group) was used to determine which group was significantly different from any other groups.
RESULTS The mean total JOA shoulder score improved from 70 ⫾ 11 points (range, 46-91 points) preoperatively to 91 ⫾ 7 points (range, 72-100 points) postoperatively.
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Table I Clinical assessment of JOA shoulder surgery classification system Points Pain (full score, 30 points) None Tenderness or slight pain with sports or severe work Mild pain with work Mild pain with activities of daily living Moderate pain but endurable (take a pain killer, sometimes, pain at night) Severe pain (often, pain at night) Impossible to move because of pain Function (full score, 20 points) Total function (10 points) Abduction strength (5 points) Normal Excellent Good Fair Poor None Durability (5 points) ⬎10 s ⬎3 s ⬍2 s Impossible Time (in seconds) holding 1-kg dumbbell horizontally with elbow extended and forearm pronated *Activities of daily living (10 points) Combing hair Making knot in back Reaching mouth Sleeping on affected side Reaching side pocket (jacket) Reaching opposite axilla
30 25 20 15 10 5 0
5 4 3 2 1 0 5 3 1 0
1 1 1 1 1 1
Points Opening and closing sliding door Reaching overhead shelf Self-hygiene care Putting on jacket Active range of motion measured in sitting position (full score ⫽ 30 points) Forward elevation (full score, 15 points) ⱖ150° ⱖ120° ⱖ90° ⱖ60° ⱖ30° ⬍30° External rotation (full score, 9 points) ⱖ60° ⱖ30° ⱖ0° ⱖ⫺20° ⬍⫺20° Internal rotation (full score, 6 points) Up to or higher than T12 Up to or higher than L5 As high as buttocks Lower than buttocks Radiographic evaluation (full score, 5 points) Normal Moderate changes or subluxation Advanced changes or dislocation Joint stability (full score, 15 points) Normal Slight instability or apprehension More severe instability or history of subluxation
1 1 1 1
15 12 9 6 3 0 9 6 3 1 0 6 4 2 0 5 3 0 15 10 5
*Subtract 1 point for each activity that the patient cannot perform except for above.
When we categorized the JOA total points into 4 grades (excellent, 90-100; good, 80-89; fair, 70-79; and poor, ⬍70), the results were excellent in 40 patients (63%), good in 19 (30%), fair in 4 (6%), and poor in none. The mean NCA angle was 18°, with a minimum of 0° and a maximum of 37°. There was a positive significant correlation between the size of the tear at the time of surgery and the NCA angle (P ⫽ .006); that is, shoulders with larger tears necessitated a greater amount of medial reinsertion of the torn cuff tendons. Correlation of NCA angle with pain score and function score
There was no significant correlation between the NCA angle and either the JOA pain score (r ⫽ 0.11, P ⫽ .39) or function score (r ⫽ 0.02, P ⫽ .88). Correlation of NCA angle with active range of motion
There was a significant negative correlation between the NCA angle and the active forward eleva-
tion angle (r ⫽ ⫺0.63, P ⬍ .001) (Figure 2). Neither active external rotation with the arm at the side nor internal rotation at the back was correlated with the NCA angle (P ⫽ .48 and .75, respectively). We categorized the NCA angle into 4 grades: grade 0 (0°-9°, n ⫽ 15), grade 1 (10°-19°, n ⫽ 11), grade 2 (20°-29°, n ⫽ 25), and grade 3 (30°-39°, n ⫽ 12) (Figure 3). The mean active forward elevation angles were as follows: 160° for grade 0, 154° for grade 1, 153° for grade 2, and 143° for grade 3. By use of the Kruskal-Wallis test, there was a significant difference between the grades (P ⬍ .001). The multiple comparisons test (␣* ⫽ .05/4 ⫽ .0125) showed that the active forward elevation angle in grade 3 patients was significantly smaller than that in any other group, with P ⫽ .001 for grade 0 versus grade 3, P ⫽ .004 for grade 1 versus grade 3, and P ⫽ .001 for grade 2 versus grade 3. The difference in the active forward elevation angle between the asymptomatic contralateral shoulder (n ⫽ 47) and the operative shoulder (⌬FE) was analyzed. ⌬FE was 1.7° in
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Correlation of NCA angle with isometric shoulder strength
Figure 2 Regression analysis of relationship between NCA angle and active forward elevation angle.
When analyzing isometric shoulder strength, we used the ratios of isometric strength of the operative shoulders to that of the contralateral asymptomatic shoulders. On the basis of physical examinations or radiographic findings, 16 patients had symptomatic contralateral shoulders; thus, the data for 47 patients were used for analysis. The mean isometric strength of forward elevation at follow-up was 87% ⫾ 15% of that in the contralateral shoulders (range, 59%-125%). The mean isometric strength of external rotation with the arm at the side was 89% ⫾ 14% of that in the contralateral shoulders (range, 59%-113%). The mean isometric strength of internal rotation at the side was 99% ⫾ 15% of that in the contralateral shoulders (range, 57%-144%). There was no significant correlation between the NCA angle and isometric strength of forward elevation, external rotation, or internal rotation (P ⫽ .47, .32, and .74, respectively). DISCUSSION
Figure 3 Active forward elevation angle according to grading of NCA angle. The NCA angle was categorized into 4 grades: grade 0 (0°-9°), grade 1 (10°-19°), grade 2 (20°-29°), and grade 3 (30°-39°). Asterisk, The mean active forward elevation angle in grade 3 patients was significantly smaller than that for any other grade (P ⬍ .01) according to the multiple comparisons test.
grade 0 patients (n ⫽ 12), 3.3° in grade 1 patients (n ⫽ 9), 3.5° in grade 2 patients (n ⫽ 20), and 15.8° in grade 3 patients (n ⫽ 6). By use of the multiple comparisons test, ⌬FE in grade 3 patients was significantly greater than that in any other group, with P ⬍ .001 for grade 0 versus grade 3, P ⫽ .002 for grade 1 versus grade 3, and P ⬍ .001 for grade 2 versus grade 3.
Medial reattachment of the cuff tendon reduces the moment arm at the cuff tendon and also decreases the articular surface area of the humeral head. There was a significant negative correlation between the amount of medial reinsertion of the cuff attachment and the active forward elevation angle. Although medial reinsertion of the torn cuff tendon had an inverse effect on the active forward elevation angle, it did not affect either the pain score or the function score. Liu et al12 reported on the biomechanical effects of medial reattachment of the cuff using cadavers, in which cuffs were reattached at 3 mm, 10 mm, and 17 mm from the anatomic cuff insertion point. They concluded that up to 10 mm of medial reattachment of the cuff did not significantly decrease the moment arm at the cuff tendon. We did not measure the actual distance from the anatomic cuff insertion point to the newly created cuff insertion point. We believe that the actual distance on the humeral head represents the amount of medial reattachment of the cuff tendon less accurately than the NCA angle, which was measured in this study because the radius of the humeral head curvature is very variable between individuals.8,9,16,17 In general, the mean radius of humeral head curvature is reported to be around 25 mm (range, 20-30 mm).8,9,16,17 If we assumed that the radius of humeral head curvature in the frontal plane was 25 mm, then 30° of the NCA angle represents approximately 13 mm of medial reattachment of cuff tendons ([2 ⫻ ⫻ 25 ⫻ 30]/360). According to our study, more than 30° of the NCA
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angle (approximately 13 mm from the anatomic cuff insertion point) produced a significant loss of the active forward elevation angle. Our study seems to be consistent with that of Liu et al.12 Another important factor that influences the condition of the repair is the tension at the repair site.3,7 The tension at the repair site and the amount of medial reinsertion of the cuff tendon are biomechanically related to one another. Davidson and Rivenburgh3 studied the relationship between the tension at the repair site and the postoperative clinical outcomes. They concluded that high tension at the repair site resulted in both poor subjective and poor objective results. There is a balance between tension at the repair site and the length of the moment arm at the cuff when a cuff is retracted. If we aim to preserve the normal length of the moment arm at the cuff, we then have to compromise by accepting high tension at the repair site. If we want to create appropriate tension at the repair site, then we have to give up preservation of the normal length of the moment arm of the cuff. We prioritized the tension at the repair site; that is, we reinserted the distal end of the cuff medial to the normal cuff insertion point according to the degree of retraction of the cuff. Although we did not measure the tension at the repair site, we believe that we were able to avoid excessively high tension because we reattached the cuff to a point where it could easily reach with the shoulder in 0° of abduction. Further prospective study is necessary to analyze the relationship between tension and the amount of medialization of the cuff. There are several reports that conclude that cuff integrity correlates with overall shoulder function.4-6,10,11,18 By reattaching the cuff tendon medial to the anatomic cuff insertion site, we thought we could reduce the cuff retear rate. Although our retear rate was 9% (9/76), which was relatively low compared with previous reports,1,4,6,10,18 we could not determine the actual retear rates because the follow-up rate was low (76/ 274). In conclusion, the amount of medial reinsertion of the cuff tendon correlated with the active forward elevation angle. The active forward elevation angle decreased with an increasing amount of medial reattachment of the cuff. Approximately 13 mm of medial reinsertion of the torn cuff tendon (assuming a humeral head radius of 25 mm8,9,17) significantly de-
J Shoulder Elbow Surg May/June 2007
creased the active forward elevation angle; therefore, less than 13 mm of medialization is recommended. REFERENCES
1. Calvert PT, Packer NP, Stoker DJ, Bayley JIL, Kessel L. Arthrography of the shoulder after operative repair of the torn rotator cuff. J Bone Joint Surg Br 1986;68:147-50. 2. Cofield RH, Lanzer WL. Pathology of rotator cuff tearing in methods of tendon repair. Orthop Trans 1985;9:42. 3. Davidson PA, Rivenburgh DW. Rotator cuff repair tension as a determinant of functional outcome. J Shoulder Elbow Surg 2000; 6:502-6. 4. Gazielly DF, Gleyze P, Montagnon C. Functional and anatomical results after rotator cuff repair. Clin Orthop Relat Res 1994: 43-53. 5. Gerber C, Fuchs B, Hodler J. The results of repair of massive tears of the rotator cuff. J Bone Joint Surg Am 2000;82:505-15. 6. Harryman DT II, Mack LA, Wang KY, Jackins SE, Richardson ML, Matsen FA III. Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff. J Bone Joint Surg Am 1991;73: 982-9. 7. Hersche O, Gerber C. Passive tension in the supraspinatus musculotendinous unit after long-standing rupture of its tendon: a preliminary report. J Shoulder Elbow Surg 1998;7:393-6. 8. Hertel R, Knothe U, Ballmer FT. Geometry of the proximal humerus and implications for prosthetic design. J Shoulder Elbow Surg 2002;11:331-8. 9. Jobe CM, Iannotti JP. Limits imposed on glenohumeral motion by joint geometry. J Shoulder Elbow Surg 1995;4:281-5. 10. Knudsen HB, Gelineck J, Sojbjerg JO, Olsen BS, Johannsen HV, Sneppen O. Functional and magnetic resonance imaging evaluation after single-tendon rotator cuff reconstruction. J Shoulder Elbow Surg 1999;8:242-6. 11. Liu SH, Baker CL. Arthroscopically assisted rotator cuff repair: correlation of functional results with integrity of the cuff. Arthroscopy 1994;10:54-60. 12. Liu J, Hughes RE, O’Driscoll SW, An KN. Biomechanical effect of medial advancement of the supraspinatus tendon. A study in cadavera. J Bone Joint Surg Am 1998;80:853-9. 13. Matsen FA III, Lippitt SB, Sidles JA, Harryman DT II. Practical evaluation and management of the shoulder. Philadelphia: Saunders; 1994. 14. McLaughlin HL. Lesions of musculotendinous cuff of the shoulder. The exposure and treatment of tears with retraction. J Bone Joint Surg 1944;26:31-51. 15. Nobuhara K, Hata Y, Komai M. Surgical procedure and results of repair of massive tears of the rotator cuff. Clin Orthop Relat Res 1994:54-9. 16. Pearl ML. Proximal humeral anatomy in shoulder arthroplasty: implications for prosthetic design and surgical technique. J Shoulder Elbow Surg 2005;14(Suppl S):99S-104S. 17. Pearl ML, Volk AG. Coronal plane geometry of the proximal humerus relevant to prosthetic arthroplasty. J Shoulder Elbow Surg 1996;5:320-6. 18. Thomazeau H, Boukobza E, Morcet N, Chaperon J, Langlais F. Prediction of rotator cuff results by magnetic resonance imaging. Clin Orthop Relat Res 1997:275-83.
We reattached the torn rotator cuff medial to the anatomic cuff insertion site if it was retracted. The purpose was to correlate the amount of medial reattachment of the cuff with shoulder function. We evaluated 63 shoulders in which repaired cuffs were followed with magnetic resonance imaging at a mean follow-up of 8 years. The amount of medial reattachment of the cuff tendon was determined by use of a T2-weighted oblique coronal view, which passed through the center of the humeral head, and was defined as the NCA angle (where N indicates the new cuff insertion point, C indicates the center of the humeral head, and A indicates the anatomic cuff insertion point). Theoretically, the more medially the cuff tendon was reattached, the greater the NCA angle. Neither the Japanese Orthopaedic Association shoulder score nor isometric strength of forward elevation was correlated with the NCA angle. The NCA angle was significantly correlated (P ⫽ .001) with the active forward elevation angle, which dramatically decreased at 30° of the NCA angle, approximately 13 mm from the original cuff insertion point, assuming a humeral head radius of 25 mm. (J Shoulder Elbow Surg 2007;16:316-320.)
T he repair of the rotator cuff is an effective method of reducing shoulder pain and restoring shoulder function. In cases in which a torn cuff is retracted, reattaching the cuff medial to the anatomic cuff insertion site is an option. By doing so, tension at the repair site can be reduced; on the other hand, the length of the moment arm of the reinserted cuff decreases, and this may weaken shoulder strength or decrease the range of motion. Although reattaching the torn cuff tendon
From the aDepartment of Orthopaedics, Kumamoto Kinoh Hospital, and bAsouda Seikeigeka Clinic, Kumamoto, and cDepartment of Physics, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo. Reprint requests: Hiroshi Takeda, MD, Department of Orthopaedics, Kumamoto Kinoh Hospital, 6-8-1, Yamamuro, Kumamoto-City, Kumamoto 860-8518, Japan (E-mail: [email protected]) Copyright © 2007 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2007/$32.00 doi:10.1016/j.jse.2006.10.001
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medial to the anatomic cuff insertion site is a common option for repairing retracted cuffs,6,12-15 there have been no clinical studies regarding the influence of medial reattachment of the cuff. We quantified the amount of medial reattachment of the torn cuff tendon trigonometrically, by use of magnetic resonance imaging (MRI), at the time of follow-up so that we could analyze the correlation of the amount of medial reattachment of cuff insertion with shoulder function. The purpose of this study was to test our hypothesis that medial reattachment of the cuff tendon influences shoulder function. To our knowledge, this is the first clinical study analyzing the effects of medial reattachment of torn cuff tendons. MATERIALS AND METHODS There were 274 open rotator cuff repairs performed at our institution from January 1989 to December 1996. When rotator cuff repair was performed, the torn cuff tendons were reattached to the site to which the cuff could reach without excessive tension, with the arm at the side. Therefore, a torn cuff tendon was reattached medial to the anatomic cuff insertion site if it was retracted. Seventy patients (seventy-six shoulders) were able to return for the long-term follow-up (ⱖ5 years). The rest of the patients could not return for this long-term follow-up because of geographic or mobility issues. MRI examinations were performed on every patient (Philips GyroScan T5-II, 0.5 T; Philips Medical Systems, Best, The Netherlands). MRI findings were determined by a radiologist who was not informed about the patients’ profiles. A high-intensity area on the T2-weighted oblique coronal view of the cuff was regarded as indicating a detached cuff. The amount of medial reattachment of the cuff tendon was determined by use of a T2-weighted oblique coronal view, which passed through the center of the humeral head, and was defined as the NCA angle (where N indicates the new cuff insertion point, C indicates the center of the humeral head, and A indicates the normal cuff insertion point) (Figure 1). The center of the humeral head (point C) was determined geometrically and checked with circular templates. The newly created cuff insertion point (point N) was determined as the most medial border of the reinserted cuff tendon. The normal cuff insertion point (point A) is the most medial insertion point of the supraspinatus tendon. In shoulders without chronic rotator cuff tears, this point is easily determined as the step-off of the greater tuberosity. However, in shoulders with large or chronic rotator cuff tears, the greater tuberosity becomes
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Isometric shoulder strength was measured with a MicroFET handheld dynamometer (Hoggan Health Industries, West Jordan, UT). Isometric strength of forward elevation was measured with the arm held at 90° of elevation in the scapular plane. Isometric strength of external rotation and internal rotation was measured with the arm at the side with 0° of rotation. The measurements were repeated 3 times, and the mean was used for statistical analysis. When analyzing isometric shoulder strength, we used the ratios of isometric strength of the operative shoulders to that of the contralateral shoulders, which were asymptomatic. Active shoulder range of motion was measured with a goniometer. Internal rotation was determined as the highest spine level to which the extended thumb could reach.
Surgical technique Figure 1 Amount of medialization of cuff attachment. The amount of medial reattachment of the cuff tendon was defined by use of a T2-weighted oblique coronal view as the NCA angle (N, new cuff insertion point; C, center of humeral head; A, normal cuff insertion point).
flat and round, and the anatomic supraspinatus insertion point is difficult to determine. In this situation, the anatomic supraspinatus insertion point (point A) was determined based on the assumption that the total arc of the articular surface (ICA angle [where I indicates the inferior margin of the articular surface, C indicates the center of the humeral head, and A indicates the normal cuff insertion point]) in the frontal plane is 150°, which has been reported as the mean of the normal population.8,9,17 To investigate the influence of medial reattachment of the cuff tendon, we analyzed shoulders that had successfully reattached cuffs. Among the initial 76 shoulders, 9 had retears of the cuffs and 4 had developed severe osteoarthritis after surgery; we excluded these 13 shoulders, leaving 63 shoulders for analysis. There were 46 men and 17 women. The mean age at the time of surgery was 52 ⫾ 10 years (range, 32-73 years). The mean age at follow-up was 60 ⫾ 10 years (range, 41-81 years). The mean duration of follow-up was 8 years 2 months (SD, 2 years; range, 5 years 1 month to 12 years 6 months). The sizes of the tears in the 63 shoulders at surgery were determined by use of the classification of Cofield and Lanzer.2 There were 11 partialthickness tears (18.4%), 10 small-sized tears (⬍1 cm) (13.2%), 15 medium-sized tears (1-3 cm) (21.1%), 25 large-sized tears (3-5 cm) (42.1%), and 2 massive tears (⬎5 cm) (5.3%). Clinical outcomes were evaluated by use of the Japanese Orthopaedic Association (JOA) shoulder scoring system. This system is based on a total of 100 points, with 30 points for pain, 20 points for function, 30 points for range of motion, 5 points for radiographic change, and 15 points for joint stability (Table I). Isometric shoulder strength (forward elevation, external rotation with the arm at the side, and internal rotation with the arm at the side) and active shoulder range of motion (forward elevation, external rotation with the arm at the side, and internal rotation behind the back) were measured by the same observer, who was blinded to the patients’ profiles.
Under general anesthesia, the patient was placed on the operating table in the beach-chair position. All of the operations were performed by one of the authors. After an anterolateral skin incision was made, the deltoid muscle was split 4 cm from the acromioclavicular joint. The deltoid origin was detached no more than 5 mm from the acromion. The coracoacromial ligament and the subacromial bursa were resected. An anterior acromioplasty was performed for all shoulders. External and internal cuff mobilization, including release of the humeroscapular interface, a relaxing incision to the cuff, cutting of the coracohumeral ligament, and release of the capsule just lateral to the superior glenoid, was performed as necessary. A bone trough was created at a site at which the cuff could reattach without creating excessive tension at the repair site, with the arm at the side. Partial-thickness tears were treated by excising the damaged areas and repairing them in the same manner as described previously. If there was lamination of the cuff, mattress sutures were placed between the superficial layers and the deep layers. Passive range-of-motion exercises were started a few days after surgery, and active range-of-motion exercises were allowed after 5 weeks. Nonsteroidal anti-inflammatory medicines were used for all patients postoperatively. Strenuous activities with the operative shoulder were not allowed for 6 months.
Statistical analysis Statistical analysis was done by use of the SPSS software package (version 11.0; SPSS, Chicago, Ill). The MannWhitney U test was used to compare the 2 unpaired groups. For paired groups of 2, the Wilcoxon signed rank test was performed. To compare more than 3 groups, the Kruskal-Wallis test was used. P ⬍ .05 was considered significant. For multiple comparisons, according to the Bonferroni adjustment procedures, ␣* (␣* ⫽ ␣/k, where k indicates the number of the group) was used to determine which group was significantly different from any other groups.
RESULTS The mean total JOA shoulder score improved from 70 ⫾ 11 points (range, 46-91 points) preoperatively to 91 ⫾ 7 points (range, 72-100 points) postoperatively.
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Table I Clinical assessment of JOA shoulder surgery classification system Points Pain (full score, 30 points) None Tenderness or slight pain with sports or severe work Mild pain with work Mild pain with activities of daily living Moderate pain but endurable (take a pain killer, sometimes, pain at night) Severe pain (often, pain at night) Impossible to move because of pain Function (full score, 20 points) Total function (10 points) Abduction strength (5 points) Normal Excellent Good Fair Poor None Durability (5 points) ⬎10 s ⬎3 s ⬍2 s Impossible Time (in seconds) holding 1-kg dumbbell horizontally with elbow extended and forearm pronated *Activities of daily living (10 points) Combing hair Making knot in back Reaching mouth Sleeping on affected side Reaching side pocket (jacket) Reaching opposite axilla
30 25 20 15 10 5 0
5 4 3 2 1 0 5 3 1 0
1 1 1 1 1 1
Points Opening and closing sliding door Reaching overhead shelf Self-hygiene care Putting on jacket Active range of motion measured in sitting position (full score ⫽ 30 points) Forward elevation (full score, 15 points) ⱖ150° ⱖ120° ⱖ90° ⱖ60° ⱖ30° ⬍30° External rotation (full score, 9 points) ⱖ60° ⱖ30° ⱖ0° ⱖ⫺20° ⬍⫺20° Internal rotation (full score, 6 points) Up to or higher than T12 Up to or higher than L5 As high as buttocks Lower than buttocks Radiographic evaluation (full score, 5 points) Normal Moderate changes or subluxation Advanced changes or dislocation Joint stability (full score, 15 points) Normal Slight instability or apprehension More severe instability or history of subluxation
1 1 1 1
15 12 9 6 3 0 9 6 3 1 0 6 4 2 0 5 3 0 15 10 5
*Subtract 1 point for each activity that the patient cannot perform except for above.
When we categorized the JOA total points into 4 grades (excellent, 90-100; good, 80-89; fair, 70-79; and poor, ⬍70), the results were excellent in 40 patients (63%), good in 19 (30%), fair in 4 (6%), and poor in none. The mean NCA angle was 18°, with a minimum of 0° and a maximum of 37°. There was a positive significant correlation between the size of the tear at the time of surgery and the NCA angle (P ⫽ .006); that is, shoulders with larger tears necessitated a greater amount of medial reinsertion of the torn cuff tendons. Correlation of NCA angle with pain score and function score
There was no significant correlation between the NCA angle and either the JOA pain score (r ⫽ 0.11, P ⫽ .39) or function score (r ⫽ 0.02, P ⫽ .88). Correlation of NCA angle with active range of motion
There was a significant negative correlation between the NCA angle and the active forward eleva-
tion angle (r ⫽ ⫺0.63, P ⬍ .001) (Figure 2). Neither active external rotation with the arm at the side nor internal rotation at the back was correlated with the NCA angle (P ⫽ .48 and .75, respectively). We categorized the NCA angle into 4 grades: grade 0 (0°-9°, n ⫽ 15), grade 1 (10°-19°, n ⫽ 11), grade 2 (20°-29°, n ⫽ 25), and grade 3 (30°-39°, n ⫽ 12) (Figure 3). The mean active forward elevation angles were as follows: 160° for grade 0, 154° for grade 1, 153° for grade 2, and 143° for grade 3. By use of the Kruskal-Wallis test, there was a significant difference between the grades (P ⬍ .001). The multiple comparisons test (␣* ⫽ .05/4 ⫽ .0125) showed that the active forward elevation angle in grade 3 patients was significantly smaller than that in any other group, with P ⫽ .001 for grade 0 versus grade 3, P ⫽ .004 for grade 1 versus grade 3, and P ⫽ .001 for grade 2 versus grade 3. The difference in the active forward elevation angle between the asymptomatic contralateral shoulder (n ⫽ 47) and the operative shoulder (⌬FE) was analyzed. ⌬FE was 1.7° in
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Correlation of NCA angle with isometric shoulder strength
Figure 2 Regression analysis of relationship between NCA angle and active forward elevation angle.
When analyzing isometric shoulder strength, we used the ratios of isometric strength of the operative shoulders to that of the contralateral asymptomatic shoulders. On the basis of physical examinations or radiographic findings, 16 patients had symptomatic contralateral shoulders; thus, the data for 47 patients were used for analysis. The mean isometric strength of forward elevation at follow-up was 87% ⫾ 15% of that in the contralateral shoulders (range, 59%-125%). The mean isometric strength of external rotation with the arm at the side was 89% ⫾ 14% of that in the contralateral shoulders (range, 59%-113%). The mean isometric strength of internal rotation at the side was 99% ⫾ 15% of that in the contralateral shoulders (range, 57%-144%). There was no significant correlation between the NCA angle and isometric strength of forward elevation, external rotation, or internal rotation (P ⫽ .47, .32, and .74, respectively). DISCUSSION
Figure 3 Active forward elevation angle according to grading of NCA angle. The NCA angle was categorized into 4 grades: grade 0 (0°-9°), grade 1 (10°-19°), grade 2 (20°-29°), and grade 3 (30°-39°). Asterisk, The mean active forward elevation angle in grade 3 patients was significantly smaller than that for any other grade (P ⬍ .01) according to the multiple comparisons test.
grade 0 patients (n ⫽ 12), 3.3° in grade 1 patients (n ⫽ 9), 3.5° in grade 2 patients (n ⫽ 20), and 15.8° in grade 3 patients (n ⫽ 6). By use of the multiple comparisons test, ⌬FE in grade 3 patients was significantly greater than that in any other group, with P ⬍ .001 for grade 0 versus grade 3, P ⫽ .002 for grade 1 versus grade 3, and P ⬍ .001 for grade 2 versus grade 3.
Medial reattachment of the cuff tendon reduces the moment arm at the cuff tendon and also decreases the articular surface area of the humeral head. There was a significant negative correlation between the amount of medial reinsertion of the cuff attachment and the active forward elevation angle. Although medial reinsertion of the torn cuff tendon had an inverse effect on the active forward elevation angle, it did not affect either the pain score or the function score. Liu et al12 reported on the biomechanical effects of medial reattachment of the cuff using cadavers, in which cuffs were reattached at 3 mm, 10 mm, and 17 mm from the anatomic cuff insertion point. They concluded that up to 10 mm of medial reattachment of the cuff did not significantly decrease the moment arm at the cuff tendon. We did not measure the actual distance from the anatomic cuff insertion point to the newly created cuff insertion point. We believe that the actual distance on the humeral head represents the amount of medial reattachment of the cuff tendon less accurately than the NCA angle, which was measured in this study because the radius of the humeral head curvature is very variable between individuals.8,9,16,17 In general, the mean radius of humeral head curvature is reported to be around 25 mm (range, 20-30 mm).8,9,16,17 If we assumed that the radius of humeral head curvature in the frontal plane was 25 mm, then 30° of the NCA angle represents approximately 13 mm of medial reattachment of cuff tendons ([2 ⫻ ⫻ 25 ⫻ 30]/360). According to our study, more than 30° of the NCA
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angle (approximately 13 mm from the anatomic cuff insertion point) produced a significant loss of the active forward elevation angle. Our study seems to be consistent with that of Liu et al.12 Another important factor that influences the condition of the repair is the tension at the repair site.3,7 The tension at the repair site and the amount of medial reinsertion of the cuff tendon are biomechanically related to one another. Davidson and Rivenburgh3 studied the relationship between the tension at the repair site and the postoperative clinical outcomes. They concluded that high tension at the repair site resulted in both poor subjective and poor objective results. There is a balance between tension at the repair site and the length of the moment arm at the cuff when a cuff is retracted. If we aim to preserve the normal length of the moment arm at the cuff, we then have to compromise by accepting high tension at the repair site. If we want to create appropriate tension at the repair site, then we have to give up preservation of the normal length of the moment arm of the cuff. We prioritized the tension at the repair site; that is, we reinserted the distal end of the cuff medial to the normal cuff insertion point according to the degree of retraction of the cuff. Although we did not measure the tension at the repair site, we believe that we were able to avoid excessively high tension because we reattached the cuff to a point where it could easily reach with the shoulder in 0° of abduction. Further prospective study is necessary to analyze the relationship between tension and the amount of medialization of the cuff. There are several reports that conclude that cuff integrity correlates with overall shoulder function.4-6,10,11,18 By reattaching the cuff tendon medial to the anatomic cuff insertion site, we thought we could reduce the cuff retear rate. Although our retear rate was 9% (9/76), which was relatively low compared with previous reports,1,4,6,10,18 we could not determine the actual retear rates because the follow-up rate was low (76/ 274). In conclusion, the amount of medial reinsertion of the cuff tendon correlated with the active forward elevation angle. The active forward elevation angle decreased with an increasing amount of medial reattachment of the cuff. Approximately 13 mm of medial reinsertion of the torn cuff tendon (assuming a humeral head radius of 25 mm8,9,17) significantly de-
J Shoulder Elbow Surg May/June 2007
creased the active forward elevation angle; therefore, less than 13 mm of medialization is recommended. REFERENCES
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