Intact Tendon Research Articles

Structural Properties of the Intact Proximal Hamstring Origin and Evaluation of Varying Avulsion Repair Techniques

Background: Although surgical repair has been reported to provide improved outcomes compared with nonoperative treatment in the management of complete proximal hamstring origin avulsions, no intact or avulsion repair biomechanical data exist to support various repair strategies or guide postoperative rehabilitation. Purpose: To compare failure load among 4 proximal hamstring tendon conditions: (1) intact, (2) repair with 2 small anchors (2S), (3) repair with 2 large anchors (2L), and (4) repair with 5 small anchors (5S). Study Design: Controlled laboratory study. Methods: Twenty-four human cadaveric hemipelvises were randomly allocated to 1 of the 4 testing groups. Intact and repaired specimens were subjected to cyclic loading at 1 Hz between 25 N and a progressively increasing maximum load that was incremented by 200 N every 50 cycles, beginning at 200 N and increasing to 1600 N. Displacement, maximum load, stiffness, number of cycles to failure, and mode of failure during cyclic loading were recorded and analyzed. Results: The intact proximal hamstring tendons failed at the highest cyclic force of all tested groups, yet no significant differences existed between the intact (1405 ± 157 N) and 5S repair (1164 ± 294 N) conditions. Both the 2S and the 2L repair groups failed at a level significantly lower than the intact hamstring (474 ± 145 N [P < .001] and 543 ± 245 N [P < .001], respectively). The maximum load attained by the 5S repairs was significantly greater than the loads attained by the 2S (P = .005) and 2L (P = .013) repairs. Conclusion: Repairs using 5 small anchors were similar to the intact tendon and were significantly stronger than repairs using only 2 large or 2 small anchors in the repair of complete avulsions of the proximal hamstring tendons. Additionally, no significant differences in strength were observed when only anchor size differed. Clinical Relevance: This finding supports the clinical investigation of postoperative range of motion rehabilitation protocols that permit full flexion and extension of the hip and knee when a 5-anchor repair construct is used.

Proper placement of the distal biceps tendon during repair improves supination strength—a biomechanical analysis

Anatomic repair of the distal biceps tendon can be difficult to achieve. This study was designed to compare the effect of anatomic and nonanatomic repairs on forearm supination torque. A nonanatomic repair re-establishes the footprint radial and more anterior to the tuberosity apex, whereas an anatomic repair re-establishes the footprint ulnar and more posterior to the tuberosity apex. Eight fresh frozen cadaver arms were surgically prepared and mounted on an elbow simulator. Controlled loads were applied to the long head and short head in positions of pronation, neutral, and supination. This was done with intact tendons and then repeated with repaired tendons that were repaired either anatomically (ulnar position) or nonanatomically (radial position). All anatomic repairs showed no difference compared with intact tendon measurements. In comparing anatomic and nonanatomic repairs, we found no differences in the supination torque when the forearm was in 45° of pronation. However, when the arm was in neutral rotation, we found that 15% less supination torque was generated by the nonanatomic repair. When the arm was tested in 45° of supination, we found that 40% less supination torque was generated in the nonanatomic repair (P = .01). This study supports the idea that an anatomic repair of the biceps tendon onto the ulnar side of the radial tuberosity is important. If the tendon is repaired too radially, the biceps will lose the cam effect and may not be able to generate full supination torque when the forearm is in neutral rotation or in supination.

Medial Biceps Sling Takedown May Be Necessary to Expose an Occult Subscapularis Tendon Tear

With a systematic approach to diagnosis, including a thorough history, physical examination, advanced imaging, and arthroscopic evaluation, most subscapularis tendon tears may be readily discovered. Occult tears, on the other hand, may escape arthroscopic detection if a high index of suspicion and certain intraoperative examination steps are lacking. We describe an occult tear pattern in which a subscapularis tendon tear was completely hidden by an intact medial biceps tendon sling. Takedown of the sling, which was expendable because a tenodesis was planned, was required to expose this occult tear. Awareness of occult subscapularis tear patterns makes diagnosis and repair possible.

Biceps Muscle Fatty Infiltration and Atrophy. A Midterm Review After Arthroscopic Tenotomy of the Long Head of the Biceps

Pathology of the long head of the biceps (LHB) tendon is commonly treated by tenotomy. High levels of clinical function and patient satisfaction are reported in the short-term. The purpose of this study was to investigate the midterm effects of tenotomy on biceps fatty infiltration and atrophy in active working-age male patients. Twenty-five men (mean age, 57 years) were evaluated at a mean follow-up of 6.7 years after tenotomy. Bilateral magnetic resonance imaging (MRI) was performed, and fatty infiltration of the biceps was assessed relative to the ipsilateral triceps. Seventeen participants had an intact contralateral LHB tendon. To assess atrophy, anterior muscle compartment volume was measured by serial cross-sectional area measurements on MRI. The tenotomized side was then compared to the healthy side in these 17 participants. Clinical scores were obtained using the QuickDASH and Oxford Elbow Score, and the occurrence of a Popeye sign and residual pain were recorded. Good clinical function was maintained at a mean follow-up time of 6.7 years (range, 4 to 10 years) (QuickDASH score of 7.1; standard error [SE], 1.8) and Oxford Elbow Score of 97.9 [SE 1.2]). Eleven of the 25 participants had a Popeye deformity. Four participants showed signs of fatty infiltration, and all were minor (grade 1). The mean decrease in total volume of the anterior musculature was 3.6%. In participants without a Popeye deformity, it was 3.3%, whereas it was 4.1% in participants with a Popeye sign (P = .8). In the midterm, LHB tenotomy in active men of working age does not result in fatty degeneration or substantial atrophy in the anterior musculature of the arm. Clinical function remains good. Level IV, therapeutic case series.

The subscapularis-sparing approach in humeral head replacement

This report represents a prospective case series evaluating an open deltopectoral approach, both radiologically and clinically, without tenotomy or complete takedown of the subscapularis tendon insertion. We hypothesized that this novel technical approach would allow preservation of the upper tendon border, thus decreasing subscapularis repair failures and fatty infiltration while simultaneously allowing accelerated rehabilitation. Fifty patients underwent humeral head replacement surgery through a subscapularis-sparing approach. In this approach, we take down only the inferior 30% to 50% of the subscapularis tendon, leaving the critical superior aspect of the tendon attached to the lesser tuberosity. Forty-three patients were included in the postoperative results (7 were lost to follow-up). Nineteen patients had a postoperative magnetic resonance imaging study, and 24 patients had ultrasound evaluation. Physical examination included belly-press and lift-off tests; follow-up included visual analog scale, American Shoulder and Elbow Surgeons, Constant, modified UCLA, Rowe, and Short Form 12 scores. All patients had a minimum 2-year follow-up. All patients had subscapularis strength equal to the opposite side as measured by lift-off, belly-press, and bear hug tests. Average postoperative scores all showed statistically significant improvement except for general health. All had an intact subscapularis tendon attachment as evaluated by either magnetic resonance imaging or ultrasound imaging. None had atrophy in the muscle belly. The subscapularis-sparing, minimally invasive approach to the glenohumeral joint provides adequate exposure to allow humeral head replacement. When the upper border of the subscapularis insertion is left intact, there is a decreased risk of postoperative failure (rupture or atrophy) of the subscapularis tendon.

Fatty degeneration and atrophy of the rotator cuff muscles after arthroscopic repair: does it improve, halt or deteriorate?

The purpose of this study was to evaluate the changes in fatty degeneration and atrophy of rotator cuff muscles after arthroscopic repair. We further assessed the factors affecting the functional outcomes and integrity of the rotator cuff. One hundred and two prospectively followed patients who underwent single-row arthroscopic repair for full-thickness rotator cuff tears between 2008 and 2010 in our institution were included. All patients underwent shoulder MRI examination before the arthroscopic repair and at the final follow-up at least 2 years after the surgical repair. Supraspinatus muscle atrophy was measured and evaluated according to the Thomazeau classification. The fatty degeneration of the cuff muscles was graded according to the Goutallier classification. Functional outcomes were assessed with the Constant shoulder score. The changes in fatty degeneration and atrophy were analyzed during the treatment period. Correlation coefficients (Pearson r) and stepwise, multiple linear regression were used to determine the relationship between the outcome variables (final Constant score and integrity of the cuff), and the predictor variables, age, sex, follow-up duration, initial muscle atrophy, final muscle atrophy, initial fatty degeneration and final fatty degeneration. Of the 102 patients reviewed, 87 patients responded and concluded the final clinical follow-up and MRI examination (85.2 % follow-up rate). There were 67 females and 20 males with a mean age of 62.5 ± 8.3 years (range 40-80 years). Mean follow-up period was 30.1 ± 5.8 months (range 24-43 months). At the final follow-up, the mean Constant shoulder score was 94.2 ± 8.2 (range 70-100), and 66 (75.9 %) patients rated as excellent, 14 (16.1 %) as good, and 7 (8.0 %) as fair. No patient had poor results. There was re-rupture in 26 (29.9 %) patients on final MRI examination. No patient had improvement in muscle atrophy and fatty degeneration. The atrophic changes between intact tendon and re-rupture cases were statistically similar (p = 0.300). The deterioration of fatty degeneration was significantly higher in the re-rupture group (p = 0.0001). The Constant shoulder score was significantly lower in patients with re-rupture (97.4 ± 5.0 versus 86.6 ± 9.3, p = 0.001).Multiple stepwise regression analysis showed that the Constant score was dependent on the final integrity of the tendon and the size of the tear (R (2) 0.420, p 0.001). The final integrity of the tendon was dependent on the age of the patient, initial and final fatty degeneration of the cuff muscles and the size of the tear (R (2) 0.669, p 0.001). Initial muscle atrophy and fatty degeneration did not improve even after a successful rotator cuff repair where the tendon anatomic integrity was maintained for at least 2 years. It may continue to deteriorate, and the best possibility was preservation of the preoperative status. On the other hand, in cases of re-rupture, fatty degeneration and atrophy continued to worsen significantly. The factors affecting tendon integrity were found to be the age of the patient, the size of the tear and the severity of preoperative fatty degeneration in the rotator cuff.

Kartogenin induces cartilage-like tissue formation in tendon-bone junction.

Tendon–bone junctions (TBJs) are frequently injured, especially in athletic settings. Healing of TBJ injuries is slow and is often repaired with scar tissue formation that compromises normal function. This study explored the feasibility of using kartogenin (KGN), a biocompound, to enhance the healing of injured TBJs. We first determined the effects of KGN on the proliferation and chondrogenic differentiation of rabbit bone marrow stromal cells (BMSCs) and patellar tendon stem/progenitor cells (PTSCs) in vitro. KGN enhanced cell proliferation in both cell types in a concentration-dependent manner and induced chondrogenic differentiation of stem cells, as demonstrated by high expression levels of chondrogenic markers aggrecan, collagen II and Sox-9. Besides, KGN induced the formation of cartilage-like tissues in cell cultures, as observed through the staining of abundant proteoglycans, collagen II and osteocalcin. When injected into intact rat patellar tendons in vivo, KGN induced cartilage-like tissue formation in the injected area. Similarly, when KGN was injected into experimentally injured rat Achilles TBJs, wound healing in the TBJs was enhanced, as evidenced by the formation of extensive cartilage-like tissues. These results suggest that KGN may be used as an effective cell-free clinical therapy to enhance the healing of injured TBJs.

Chemokine expression of CCL2, CCL3, CCL5 and CXCL10 during early inflammatory tendon healing precedes nerve regeneration: an immunohistochemical study in the rat.

Chemokines are major promoters of repair and may regulate nerve ingrowth that is essential in tendon healing. The purpose of this study was to assess the temporal occurrence of different chemokines during Achilles tendon healing in relation to sensory nerve regeneration. Chemokine presence in tendon healing has not been studied previously. Chemokine expression, nerve regeneration, angiogenesis and inflammatory cell occurrence during healing of Achilles tendon rupture in the rat were studied by immunohistochemistry and histology including semiquantitative assessment. Markers for chemokines (CCL5, CCL2, CCL3, CXCL10), nerves (PGP-9.5) and sensory neuropeptide substance P (SP) were analysed at different time points (1 day-16 weeks) post-rupture. In intact tendons (controls) immunoreactivity to all chemokines, PGP-9.5 and SP were confined to the tendon surroundings. After rupture, there was rapid increase in the tendon proper of the chemokines studied, all exhibiting their peak expression at week 1. Subsequently, at weeks 2-6, emerging inflammatory cells and maximum sprouting of PGP-/SP-positive nerves were observed close to newly formed blood vessels within the tendon proper, while chemokine expression already decreased. During weeks 6-8, PGP-/SP-positive nerves withdrew from the rupture site and relocated together with the chemokines in the surrounding tendon. Early chemokine expression in the healing tendon precedes ingrowth of new nerves, angiogenesis and emergence of inflammatory cells. The fine-tuned temporal and spatial appearance of chemokines suggests a chemoattractant role for inflammatory cell migration and possibly also a role in angiogenesis and neurogenesis. Chemokines may thus exhibit vital targets for biological modulation of tendon repair.

Expressional changes in growth and inflammatory mediators during Achilles tendon repair in diabetic rats: new insights into a possible basis for compromised healing.

Dysregulation of growth and inflammatory mediators might contribute to defective tissue homeostasis and healing, as commonly observed in sedentary lifestyles and in conditions such as diabetes mellitus type-2. The present study aims to assess expression changes in growth and inflammatory mediators in the intact and healing Achilles tendon of type-2 diabetic rats. The study utilized 11 male diabetic Goto-Kakizaki (GK) and 10 age- and sex-matched Wistar control rats. The right Achilles tendon was transected in all animals, whereas the left Achilles tendon remained intact. At 2weeks post-injury, intact and injured tendons were assessed for gene expression for VEGF, Tβ-4, TGF-β1, IGF-1, COX-2, iNOS, HIF-1α, and IL-1β by quantitative reverse transcription plus the polymerase chain reaction, and their protein distribution was studied by immunolocalization. In injured tendons of diabetic GK rats, VEGF and Tβ-4 mRNA and corresponding protein levels were significantly down-regulated compared with those of injured Wistar controls. Compared with intact tendons of diabetic GK rats, TGF-β1, IGF-1, and COX-2 RNA levels were higher, whereas iNOS mRNA levels were lower in injured tendons of diabetic GK rats. Within Wistar controls, healing at 2weeks post-injury led to significantly down-regulated VEGF and iNOS mRNA levels in injured tendons, whereas TGF-β1 and HIF-1α mRNA levels increased compared with intact tendons. Thus, dysregulation of inflammatory and growth mediators occurs in type-2 diabetes injured tendons. Our data suggest that therapeutic modulation of Tβ-4 and VEGF represent a new regenerative approach in operated, injured, or degenerative tendon diseases in diabetes.

An Augmentation Suture Technique for Arthroscopic Rotator Cuff Repair

The double-row suture technique and the suture-bridge technique have been used for rotator cuff repair to decrease the occurrence of retears. However, when only the degenerated tendon end is sutured, the risk of retear remains. The augmentation suture technique is a new procedure that connects the intact medial tendon to the lateral greater tuberosity, and this approach may protect the initial repair site. The procedures for this technique are as follows: 2 sutures are placed through the medial intact tendon, the cuff tear is repaired by the single-row technique, 2 sutures are pulled laterally over the single-row repair site, and 2 sutures are fixed at the lateral greater tuberosity with a push-in–type anchor. This technique is simple and easy and does not require special equipment. Moreover, this approach can augment the single-row repair technique without creating high tension at the cuff end.

Arthroscopic partial shoulder resurfacing.

The purpose of this study was to report patients' clinical and subjective outcomes 2 years after arthroscopic-assisted partial resurfacing of the humeral head. In this prospective case series, 11 patients (4 females, 7 males; median age, 59 years; range 47-72) underwent arthroscopic-assisted partial shoulder resurfacing between April 2010 and March 2011. Clinical conditions and subjective assessments were evaluated before surgery and at 6 weeks, 3 and 6 months, and then annually after surgery using the Constant score (CS), active range of motion (ROM), the visual analogue scale (VAS) for pain, the American Shoulder and Elbow Surgeons scale (ASES), and the subjective shoulder value (SSV). Radiological outcomes and major complications were monitored. The mean CS improved significantly from 54.6 ± 13.6 preoperatively to 72.9 ± 17.2 points 6 weeks postoperatively (P = 0.009). At the 2-year follow-up, the mean CS had further increased to 86.5 ± 14.3 points (P < 0.001). Trends towards increasing ROMs were detected. VAS, ASES, and SSV significantly improved from baseline to the first follow-up and maintained improvement after 2 years. One patient required revision surgery owing to a technical failure and two patients because of rapidly progressive osteoarthritis. Ten of 11 patients (91 %) claimed that they would undergo arthroscopic partial shoulder resurfacing again. Arthroscopic-assisted partial humeral head resurfacing, which has the advantages of bone stock preservation and the maintenance of an intact subscapularis tendon, allowed immediate postoperative mobilization and provided significant improvements in subjective outcomes, especially for pain relief in active patients without severe glenoid cartilage wear. Therapeutic case series, Level IV.

Preoperative Factors Affecting Footprint Coverage in Rotator Cuff Repair

Background: One of the goals of rotator cuff repair is to restore the torn tendon to its original insertion anatomically. However, it is sometimes difficult to restore the entire footprint. Purpose: This study was undertaken to evaluate the variables affecting this repair coverage and to discern the differences in retear rate and clinical results between complete and incomplete footprint coverage in rotator cuff surgery. Study Design: Case series; Level of evidence, 4. Methods: From 2007 to 2009, a total of 85 consecutive repairs for medium-to-large rotator cuff tears were identified as having complete or incomplete coverage of their original footprints. We defined the complete footprint coverage (CC) group as patients who had >50% of their footprint covered during repair and the incomplete (IC) group as <50% of their footprint. Factors affecting the amount of footprint coverage were evaluated, and multivariable analysis was conducted to identify independent factors. To assess the final outcome according to the amount of footprint coverage, retear and clinical outcomes were compared between the CC and IC groups. Results: Fifty-seven repairs were defined in the CC group and 28 repairs in the IC group. Preoperatively, age, tear size in coronal oblique and sagittal oblique planes, Goutallier fatty infiltration, and atrophy of the supraspinatus affected the amount of footprint coverage in univariate analysis. In multivariable analysis, however, tear size in the coronal plane was the only independent factor affecting footprint coverage in rotator cuff repair. On postoperative MRI, 45.6% of the CC group had an intact tendon, 45.6% had a delaminated partial retear, and 8.8% had a full-thickness retear; in the IC group, 17.9% had an intact tendon, 60.7% had a delaminated partial retear, and 21.4% had a full-thickness retear. There was a statistically significant difference in the proportion of tendon integrity between groups (P = .028). Clinical scores and range of motion at final follow-up showed no difference between the 2 groups. Conclusion: Tear size in the coronal plane was the only independent factor affecting the amount of footprint coverage. Repair quality based on retear classification was different between the 2 groups. However, both complete and incomplete footprint coverage in rotator cuff repair showed no differences in clinical scores and range of motion at short-term follow-up.

Relationship of individual scapular anatomy and degenerative rotator cuff tears

The etiology of rotator cuff disease is age related, as documented by prevalence data. Despite conflicting results, growing evidence suggests that distinct scapular morphologies may accelerate the underlying degenerative process. The purpose of the present study was to evaluate the predictive power of 5 commonly used radiologic parameters of scapular morphology to discriminate between patients with intact rotator cuff tendons and those with torn rotator cuff tendons. A pre hoc power analysis was performed to determine the sample size. Two independent readers measured the acromion index, lateral acromion angle, and critical shoulder angle on standardized anteroposterior radiographs. In addition, the acromial morphology according to Bigliani and the acromial slope were determined on true outlet views. Measurements were performed in 51 consecutive patients with documented degenerative rotator cuff tears and in an age- and sex-matched control group of 51 patients with intact rotator cuff tendons. Receiver operating characteristic analyses were performed to determine cutoff values and to assess the sensitivity and specificity of each parameter. Patients with degenerative rotator cuff tears demonstrated significantly higher acromion indices, smaller lateral acromion angles, and larger critical shoulder angles than patients with intact rotator cuffs. However, no difference was found between the acromial morphology according to Bigliani and the acromial slope. With an area under the receiver operating characteristic curve of 0.855 and an odds ratio of 10.8, the critical shoulder angle represented the strongest predictor for the presence of a rotator cuff tear. The acromion index, lateral acromion angle, and critical shoulder angle accurately predict the presence of degenerative rotator cuff tears.

Coherent X-Ray Imaging of Collagen Fibril Distributions within Intact Tendons

The characterization of the structure of highly hierarchical biosamples such as collagen-based tissues at the scale of tens of nanometers is essential to correlate the tissue structure with its growth processes. Coherent x-ray Bragg ptychography is an innovative imaging technique that gives high resolution images of the ordered parts of such samples. Herein, we report how we used this method to image the collagen fibrillar ultrastructure of intact rat tail tendons. The images show ordered fibrils extending over 10–20 μm in length, with a quantifiable D-banding spacing variation of 0.2%. Occasional defects in the fibrils distribution have also been observed, likely indicating fibrillar fusion events.

Degenerative disease in rotator cuff tears: what are the biochemical and histological changes?

The histopathological changes associated with rotator cuff tears include thinning and disorganization of collagen fibers, the presence of granulation tissue, increased levels of glycosaminoglycans, fibrocartilaginous metaplasia, calcification, fatty infiltration, and necrosis of the tendon margin with cell apoptosis. The biochemical changes include an increase in the expression of matrix metalloproteinases (MMPs) and a decrease in tissue inhibitor of metalloproteinases (TIMP) messenger ribonucleic acid expression. Histological evidence of tendinopathy has been found in patients with rotator cuff tear. Biochemical changes include significant increases in MMP1, MMP2, MMP3, and in TIMP1 and TIMP2 levels, not only at the lateral supraspinatus edge, but also in the macroscopically intact portion of the supraspinatus tendon and in the intact subscapularis. The tissue in the ruptured area of the supraspinatus tendon undergoes marked rearrangement at molecular levels. This involves the activity of MMP1, 2, and 3 and supports a critical role of MMPs in tendon physiology. Intact parts of the torn supraspinatus tendon can present the histopathological changes associated with rotator cuff tears. These findings suggest that biochemical changes can already occur in a macroscopically intact tendon and seem to point to a global degenerative process in the shoulder.

Non-Trophic Cutaneous Ulcers in Lepromatous Leprosy

A 44-year-old woman had progressive burning parasthesias and sensory loss in both upper and lower limbs, followed by weakness of distal muscles of the hands and feet for four years. She had redness and swelling of both hands and feet, multiple painless ulcers over the dorsum of the fingers (Figure 1A ) and feet (Figure 1B), and thickened, non-tender, bilateral, ulnar, superficial cutaneous branch of radial and common peroneal nerves. She also had predominant small fiber sensory polyneuropathy in a glove and stocking pattern, intrinsic muscle weakness of the hands and feet, and intact deep tendon reflexes. Results of hematologic and biochemical tests were within references ranges. Tests results for vasculitis and viral markers were negative. A nerve conduction study showed asymmetrical predominantly axonal sensorimotor polyneuropathy (Figure 3 ) and absent waveforms on sympathetic skin response testing on both upper and lower limbs. A split skin smear was positive for acid-fast bacilli by Ziehl-Nielsen staining (Figure 2A, B). A skin biopsy from the leg showed dermal perivascular lymphocytic infiltrates, nerve twig inflammation, and positive staining for lepra bacilli. Figure 1. A, Multiple ulcers on the dorsum of the fingers (arrows) of the patient with associated swelling and redness. B, Active ulcers on the dorsum of the big toe and midfoot (arrows) and a healed scar on the upper dorsum. Figure 2. Ziehl-Nielsen staining of the split skin smear (A, B) revealing acid fast bacilli (white arrows). Figure 3. Nerve conduction parameters for the patient and normal reference values (N/A: Not Applicable). Glove and stocking sensory loss in lepromatous leprosy is caused by involvement of small dermal sensory and autonomic nerve fibers,1 whereas non-trophic ulcers are caused by cutaneous vasculitis and small fiber involvement by lepra bacilli.1,2 The patient was given a multi-bacillary regimen2 (dapsone, 100 mg/day; rifampicin, 600 mg/day; and clofazimine, 50 mg/day) and showed symptomatic healing of cutaneous ulcers and reduction of burning paraesthesias at two-months follow-up.

Distal Pectoralis Major Tears

Distinction between musculotendinous tears of the pectoralis major and distal tendon avulsions is important, as the latter typically requires surgical repair. The objective of this study was to characterize the sonographic appearances of surgically proven distal tendon avulsion tears of the pectoralis major. A retrospective search of the radiology database (2001-2011) revealed 22 cases of pectoralis major tears on sonography, of which 9 had surgical correlation. Sonograms were retrospectively characterized by 3 fellowship-trained musculoskeletal radiologists in consensus with respect to the location and size of the fluid collection and the presence of tendon or tendonlike tissue superficial to the biceps brachii tendon. At surgery, complete distal tendon avulsions or tears of the sternal head of the pectoralis were present in all 9 cases: isolated in 6 and combined with clavicular head tears in 3. The location of the fluid collection was at the musculotendinous junction in 89% (8 of 9) and medial to the biceps brachii tendon in 11% (1 of 9), with a mean largest dimension of 3.8 cm (range, 0.7-6.2 cm). In no case was fluid seen at the humeral attachment of the pectoralis. In 67% (6 of 9), linear thickened hypoechoic tissue was seen superficial to the biceps brachii tendon, which simulated an abnormal but intact tendon, whereas in 33% (3 of 9), a normal distal pectoralis tendon was seen. Surgically proven distal pectoralis major tendon avulsions most commonly showed fluid collections at the musculotendinous junction and not at the humeral shaft, with either a normal tendon or hypoechoic tendonlike tissue over the biceps brachii long-head tendon. These findings may potentially cause misdiagnosis of distal tendon avulsions or tears as musculotendinous injuries.

Platelet-Rich Plasma for Rotator Cuff Repair

Rotator cuff tears are a common cause of shoulder pain and disability. Because they combine both traumatic and degenerative elements, the surgical repair can be challenging. Even after surgical intervention, tendon residual defects or "retears" often develop. Risk factors for tendon "retears" include patient age, number of tendons involved, tear size, and smoking. Platelet-rich plasma (PRP) is a supraphysiological concentration of platelets, which may be able to positively augment rotator cuff tendon healing. Not all PRPs are the same and those containing higher leukocyte levels may be detrimental to tendon healing. Thrombin activation triggers an immediate release of growth factors from the PRP and may actually inhibit some parts of the healing response. As yet, the clinical data does not conclusively prove a benefit from PRP, but discernment is required in evaluating the published results. As different PRPs may act differently and the results may be dose dependent requiring more PRP to achieve a beneficial threshold. How success is measured (clinical outcomes vs. intact cuff tendons) and how long the patients are followed are also critical items. Currently, the PRP fibrin matrix version holds the greatest promise for improving clinical success after rotator cuff tendon repair.

The Effect of Pulley Reconstruction on Maximum Flexion, Bowstringing, and Gliding Coefficient in the Setting of Zone II Repair of FDS and FDP: A Cadaveric Investigation

The purpose of this experiment was to determine the effect of A2 pulley reconstruction on gliding coefficient (GC), bowstringing, and proximal interphalangeal (PIP) joint maximum flexion angle after zone II repair of flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) lacerations. Fresh frozen cadaver forearms were mounted, and the wrist and MCP joints fixed. FDS and FDP tendons were dissected free, and sequential loads were applied while digital images were captured. The dissected digit with intact native A2 pulley, FDS, and FDP tendons was used as the control (group 1). Zone II lacerations followed by four-stranded repair of FDP plus epitendinous suture and repair of FDS were then performed, and the data recorded (group 2). A2 pulley excision and reconstruction with a loop of palmaris longus autograft was then completed and the specimens sequentially loaded and photographed (group 3). Using the digital images, GC, bowstringing, and maximum flexion angle were calculated. No difference in maximum flexion angle was observed across the three testing conditions. Zone II laceration and subsequent FDS and FDP tendon repair significantly increased the GC for group 2 specimens; however, pulley reconstruction alleviated some of this increase for group 3. Bowstringing was significantly greater after pulley reconstruction, with a mean increase of 1.9mm at maximum flexion for group 3 specimens relative to group 1 controls. Strong flexor tendon repairs are needed to prevent gap formation and subsequent triggering; however, the increased bulk from these large repairs can itself produce deleterious triggering, as well as tendon abrasion. Pulley reconstruction, in the setting FDP and FDS repair (group 3), significantly reduced the GC relative to tendon repair alone (group 2). While bowstringing was significantly greater after pulley reconstruction (group 3), it averaged only 1.9mm over group 1 specimens and did not compromise maximum flexion angle compared to the uninjured controls (group 1) or the isolated tendon repair digits (group 2).

MR versus MR arthrography in detection of supraspinatus tendon tears in patients without previous shoulder surgery

We report the prevalence of supraspinatus tendon tears seen on MR arthrography that are not seen on conventional MR exam in the same patient population. A total of 150 consecutive conventional shoulder MR and MR arthrography exams performed on the same patients who went on to arthroscopy were reviewed retrospectively by consensus reading of two musculoskeletal radiologists. Full-thickness supraspinatus tendon tears were assessed. None of the patients had previous shoulder surgery. There were 113 full-thickness supraspinatus tendon tears seen on conventional MR exam while there were 119 full-thickness supraspinatus tendon tears seen on MR arthrography. The six additional full-thickness supraspinatus tendon tears seen on MR arthrography but not seen on conventional MR exam were confirmed at arthroscopy. Some full-thickness supraspinatus tendon tears are not seen on conventional MR exam but are seen on MR arthrography. This is most likely due to fibrosis at the supraspinatus tendon tear site simulating an intact tendon on conventional MR.