Allograft Anterior Cruciate Ligament Reconstruction Fails at a Greater Rate in Patients Younger Than 34 Years.

Purpose: To characterize the secondary anterior cruciate ligament (ACL) injury rates after primary allograft anterior cruciate ligament reconstruction (ACLR) and to identify the age cut-score at which the risk of allograft failure decreases. Methods: All patients who underwent primary ACLR within a single orthopaedic department between January 2005 and April 2020 were contacted at a minimum of 2 years post-ACLR to complete a survey regarding complications experienced post-surgery, activity level, and perceptions of knee health. Patients were excluded for incidence of previous ACLR (ipsilateral or contralateral) and/or age younger than 14 years. Relative proportions were calculated, binary regression analysis was performed, and receiver operating characteristic analysis was used to identify the threshold age for maximal sensitivity and specificity to predict high risk of allograft failure, defined as undergoing revision ACLR. Results: Of the 939 surveys completed, 398 patients underwent primary allograft ACLR (mean age 39.5 years; range 16.0-66.1 years; 54.3% female). The secondary ACL injury rate was 11.6% (5.8% ipsilateral revision ACLR, 5.8% contralateral ACL injury). Male and female patients had similar revision (5.5% male, 6.0% female, P = .82) and contralateral ACL injury rates (6.6% male, 5.1% female, P = .52). Receiver operating characteristic analysis indicated that age ≤34 years was threshold for differentiating high risk of allograft failure (area under the curve 0.65, 95% confidence interval 0.55-0.76; P = .014). Patients aged ≤34 years had a greater secondary injury rate than patients >34 years (20.4% (10.2% revision ACLR, 10.2% contralateral ACL injury) versus 6.9% (3.5% revision ACLR, 3.5% contralateral ACL injury; P < .001). Binary regression analysis demonstrated that decreasing age was associated with increased risk of graft failure (χ2 = 7.9, P = .02.). Conclusions: Allograft ACLR showed similar failure rates between sexes but displayed suboptimal graft failure outcomes in younger and active patients. By age 34 years, the increased revision risk for younger patients diminished. Level of Evidence: Level IV, therapeutic case series.

Glenoid Version Assessment When the CT Field of View Does Not Permit the Friedman Method: The Robertson Method.

Background: To improve spatial resolution, current clinical shoulder cross-sectional imaging studies reduce the field of view of the shoulder, excluding the medial scapula border and preventing glenoid version measurement according to the Friedman method. Purpose: To evaluate a method to accurately and reliably measure glenoid version on cross-sectional shoulder images when the medial scapula border is not included in the field of view, and to establish measurements equivalent to the Friedman method. Study Design: Controlled laboratory study. Methods: Sixty-five scapulae underwent computed tomography (CT) scanning with an optimal shoulder CT-positioning protocol. Glenoid version was measured on CT images of the full scapula using the Friedman method. We developed a measurement method (named the Robertson method) based on the glenoid vault version from partial scapula images, with a correction angle subtracted from the articular-surface-glenoid vault measurement. Comparison with the Friedman method defined the accuracy of the Robertson method. Three observers tested inter- and intraobserver reliability of the Robertson method. Accuracy was statistically evaluated with t tests and reliability with the intraclass correlation coefficient (ICC). Results: The statistical distribution of glenoid version was similar to published data,-0.5° ± 3° [mean ± SD]. The initial measurement using the Robertson method resulted in a more retroverted angle compared with the Friedman method, and a correction angle of 7° was then applied. After this adjustment, the difference between the 2 methods was nonsignificant (0.1° ± 4°; P > .65). Reliability of the Robertson method was excellent, as the interrater ICC was 0.77, the standard error of measurement (SEM) was 1.1° with P < .001. The intrarater ICC ranged between 0.84 and 0.92, the SEM ranged between 0.9° and 1.2° with P < .01. Conclusion: A validated glenoid version measurement method is now available for current clinical shoulder CT protocols that reliably create Friedman-equivalent values. Clinical Relevance: Friedman-equivalent values may be made from common clinical CTs of the shoulder and compared with prior and future Friedman measurements of the scapula.

Factors influencing operative time in arthroscopic rotator cuff repair: a comparison of knotless single-row vs. transosseous equivalent dual-row techniques.

BACKGROUND: Despite the widespread use of arthroscopic rotator cuff repair (aRCR), there remains considerable debate on the benefits of a dual-row vs. a single-row (SR) repair technique. This study compares operative time of a knotless SR technique with transosseous equivalent (TOE) dual-row technique for aRCR and defines patient-specific factors that affect operative time. METHODS: Data from 118 patients who underwent aRCR with a knotless SR technique was compared with data from 95 patients who underwent aRCR with a TOE technique by a single surgeon between 2014 and 2018. Baseline patient demographic information and operative time were recorded and compared between the 2 groups. Subgroup analysis was performed to determine if demographic information or tear size influenced operative time. RESULTS: The average operative time in the SR group was 75.68 minutes and the average operative time in the TOE group was 89.24 minutes (P < .001). When controlling for all concomitant procedures, the operative time in the TOE group was 8.1 minutes longer than the SR group (P = .029). Average tear size in an anterior-posterior direction was larger in the TOE group vs. the SR group, 26.09 mm vs. 15.18 mm (P < .001). CONCLUSION: When controlling for concomitant procedures, a knotless, TOE dual-row technique for aRCR adds an average of 8 minutes' operative time compared with a knotless SR technique. This was despite a significantly larger tear size in the TOE group.

Biceps Tenodesis for Type II SLAP Tears.

Tears of the superior glenoid labrum are a common cause of shoulder pain and disability, especially in overhead athletes such as pitchers, swimmers, and volleyball players. Type II SLAP lesions have been the most clinically important superior labral pathology, and the management of this lesion has been a very controversial topic. Currently, there are no high level studies in the literature to guide treatment. While the few level 3 and level 4 evidence studies that are available following arthroscopic repair of type II SLAP lesions all report reasonable overall patient satisfaction, persistent postoperative pain is common and associated with a low return to pre-injury level of sports participation. There has been a recent school of thought that biceps tenodesis, which maintains the length-tension relationship of the long head of biceps, should be the procedure of choice for patients with isolated type II SLAP lesions. The current paper reviews the role biceps tenodesis plays in the management of type II SLAP tears.

Two fixation methods for acromioclavicular joint reduction during coracoclavicular ligament reconstruction: a biomechanical analysis.

One specimen from each of six pairs of cadaveric shoulders underwent a semitendinosus coracoclavicular ligament reconstruction with a hook plate used for acromioclavicular joint reduction, while on the other specimen a polydioxanone (PDS) suture braid was utilized. Cyclical loading followed by maximal load-to-failure testing was performed. Displacement during cyclical loading, loads to 50% and 100% displacement, stiffness, and maximal load to failure were determined for all specimens. Results showed that the locking hook plate allowed significantly less displacement of the coracoclavicular interval during cyclical loading (3.41 vs. 9.67 mm, p = .0081) and withstood significantly higher loads before both 50% (225.5 vs. 107.7 N, p = .0197) and 100% displacement (410.6 vs. 240.1 N, p = .0077). The locking hook plate was found to be significantly stiffer than the PDS suture braid (28.2 vs. 18.4 N/mm, p = .0029), but there was no difference in maximal load to failure between the two fixation methods (hook plate, 434.4 N; PDS, 476.7 N; p = .76).

Subpectoral biceps tenodesis for the treatment of type II and IV superior labral anterior and posterior lesions.

BACKGROUND: Surgical repair remains the gold standard for most type II and type IV superior labral anterior and posterior (SLAP) lesions that fail nonoperative management. However, most recently, there have been data demonstrating unacceptably high failure rates with primary repair of type II SLAP lesions. Biceps tenodesis may offer an acceptable, if not better, alternative to primary repair of SLAP lesions. HYPOTHESIS: Subpectoral biceps tenodesis provides satisfactory, reproducible outcomes for the treatment of type II and type IV SLAP lesions. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients who underwent subpectoral biceps tenodesis and labral debridement for type II and type IV SLAP lesions by a single board-certified shoulder surgeon from 2006 to 2012 were evaluated. Exclusion criteria included those patients who underwent biceps tenodesis with an associated rotator cuff repair, anterior labral repair, or posterior labral repair. Outcome measures included the visual analog scale (VAS) for pain, the American Shoulder and Elbow Surgeons (ASES) score, and demographic data. RESULTS: Between 2006 and 2012, a total of 36 subpectoral biceps tenodesis procedures were performed in 33 patients for type II or IV SLAP lesions. Twenty-six patients with 29 shoulder surgeries were available for follow-up. The average age was 46.7 years, with 16 male and 10 female patients participating in the study. The average follow-up was 40.17 months. There was a significant improvement in ASES and VAS scores: 48.1 and 6.4 preoperatively compared with 87.5 and 1.5 postoperatively, respectively (P < .001). There was no significant difference based on SLAP lesion type, patient age, or patient sex. Of 29 shoulders, 26 (89.66%) were able to return to the previous level of activity. CONCLUSION: This study adds to the evolving literature supporting biceps tenodesis as a viable treatment for type II and IV SLAP lesions. Patient age had no effect on the outcomes. Based on these results, biceps tenodesis is a safe, effective, and technically straightforward alternative to primary SLAP repair in patients with type II and IV SLAP tears.

Comparison of the effect of medical assistants versus certified athletic trainers on patient volumes and revenue generation in a sports medicine practice.

BACKGROUND: Research has shown increases in efficiency and productivity by using physician extenders (PEs) in medical practices. Certified athletic trainers (ATCs) that work as PEs in primary care sports medicine and orthopaedic practices improve clinic efficiency. HYPOTHESIS: When compared with a medical assistant (MA), the use of an ATC as a PE in a primary care sports medicine practice will result in an increase in patient volume, charges, and collections. STUDY DESIGN: Cross-sectional study. METHODS: For 12 months, patient encounters, charges, and collections were obtained for the practices of 2 primary care sports medicine physicians. Each physician was assisted by an ATC for 6 months and by an MA for 6 months. Eighty full clinic days were examined for each physician. RESULTS: Statistically significant increases were found in all measured parameters for the ATC compared with the MA. Patient encounters increased 18% to 22% per day, and collections increased by 10% to 60% per day. CONCLUSION: ATCs can optimize orthopaedic sports medicine practice by increasing patient encounters, charges, and collections. CLINICAL RELEVANCE: Orthopaedic practices can be more efficient by using ATCs or MAs as PEs.

A biomechanical analysis of point of failure during lateral-row tensioning in transosseous-equivalent rotator cuff repair.

PURPOSE: The purpose of this study was to determine the maximum load and point of failure of the construct during tensioning of the lateral row of a transosseous-equivalent (TOE) rotator cuff repair. METHODS: In 6 fresh-frozen human shoulders, a TOE rotator cuff repair was performed, with 1 suture from each medial anchor passed through the tendon and tied in a horizontal mattress pattern. One of 2 limbs from each of 2 medial anchors was pulled laterally over the tendon. After preparation of the lateral bone for anchor placement, the 2 limbs were passed through the polyether ether ketone (PEEK) eyelet of a knotless anchor and tied to a tensiometer. The lateral anchor was placed into the prepared bone tunnel but not fully seated. Tensioning of the lateral-row repair was simulated by pulling the tensiometer to tighten the suture limbs as they passed through the eyelet of the knotless anchor. The mode of failure and maximum tension were recorded. The procedure was then repeated for the second lateral-row anchor. RESULTS: The mean load to failure during lateral-row placement in the TOE model was 80.8 ± 21.0 N (median, 83 N; range, 27.2 to 115.8 N). There was no statistically significant difference between load to failure during lateral-row tensioning for the anterior and posterior anchors (P = .84). Each of the 12 constructs failed at the eyelet of the lateral anchor. Retrieval analysis showed no failure of the medial anchors, no medial suture cutout through the rotator cuff tendon, and no signs of gapping at the repair site. CONCLUSIONS: Our results suggest that the medial-row repair does not appear vulnerable during tensioning of the lateral row of a TOE rotator cuff repair with the implants tested. However, surgeons should exercise caution when tensioning the lateral row, especially when lateral-row anchors with PEEK eyelets are implemented. CLINICAL RELEVANCE: For this repair construct, the findings suggest that although the medial row is not vulnerable during lateral-row tensioning of a TOE rotator cuff repair, lateral-row anchors with PEEK eyelets appear vulnerable to early failure.

Shoulder external rotation fatigue and scapular muscle activation and kinematics in overhead athletes.

CONTEXT: Glenohumeral external rotation (GH ER) muscle fatigue might contribute to shoulder injuries in overhead athletes. Few researchers have examined the effect of such fatigue on scapular kinematics and muscle activation during a functional movement pattern. OBJECTIVE: To examine the effects of GH ER muscle fatigue on upper trapezius, lower trapezius, serratus anterior, and infraspinatus muscle activation and to examine scapular kinematics during a diagonal movement task in overhead athletes. SETTING: Human performance research laboratory. DESIGN: Descriptive laboratory study. PATIENTS OR OTHER PARTICIPANTS: Our study included 25 overhead athletes (15 men, 10 women; age = 20 ± 2 years, height = 180 ± 11 cm, mass = 80 ± 11 kg) without a history of shoulder pain on the dominant side. INTERVENTION(S): We tested the healthy, dominant shoulder through a diagonal movement task before and after a fatiguing exercise involving low-resistance, high-repetition, prone GH ER from 0° to 75° with the shoulder in 90° of abduction. MAIN OUTCOME MEASURE(S): Surface electromyography was used to measure muscle activity for the upper trapezius, lower trapezius, serratus anterior, and infraspinatus. An electromyographic motion analysis system was used to assess 3-dimensional scapular kinematics. Repeated-measures analyses of variance (phase × condition) were used to test for differences. RESULTS: We found a decrease in ascending-phase and descending-phase lower trapezius activity (F(1,25) = 5.098, P = .03) and an increase in descending-phase infraspinatus activity (F(1,25) = 5.534, P = .03) after the fatigue protocol. We also found an increase in scapular upward rotation (F(1,24) = 3.7, P = .04) postfatigue. CONCLUSIONS: The GH ER muscle fatigue protocol used in this study caused decreased lower trapezius and increased infraspinatus activation concurrent with increased scapular upward rotation range of motion during the functional task. This highlights the interdependence of scapular and glenohumeral force couples. Fatigue-induced alterations in the lower trapezius might predispose the infraspinatus to injury through chronically increased activation.

Anterior cruciate ligament femoral tunnel drilling through anteromedial portal: axial plane drill angle affects tunnel length.

PURPOSE: The purpose of this study was to correlate femoral tunnel length with axial drilling angle through the anteromedial portal. METHODS: Ten anatomically correct Sawbones knee models (Pacific Research Laboratories, Vashon, WA) were used for this study. With the knee flexed to 120°, tunnels were drilled through a simulated anterior medial portal with a custom outrigger guide. The guide provided consistently reproducible drilling angles of 20°, 40°, and 60° in the axial plane. Femoral tunnel lengths were recorded for each knee at each drilling angle. A 1-way analysis of variance (α = .05) was conducted to compare tunnel length in the 3 groups. Multiple comparisons were conducted by use of a Tukey post hoc test. RESULTS: The mean femoral tunnel lengths at 20°, 40°, and 60° were 37.0 mm, 36.9 mm, and 32.3 mm, respectively. The tunnels drilled at 20° and 40° were significantly longer than the 60° group (P < .001). CONCLUSIONS: Our findings suggest that drilling femoral tunnels through an anteromedial portal at an axial angle of 20° or 40° produces longer femoral tunnels than with an axial drilling angle of 60°. CLINICAL RELEVANCE: On the basis of this study, we recommend a 40° angle when approaching the lateral wall during femoral tunnel drilling through the anteromedial portal to optimize tunnel length while avoiding the acute angle and oblique entry of a 20° angle.

Transfer of the latissimus dorsi as a salvage procedure for failed debridement and attempted repair of massive rotator cuff tears.

Seven patients who had a previously failed attempt at debridement and repair of a massive rotator cuff tear were managed with latissimus dorsi transfer. Patient age averaged 63 years and average follow-up was 31 months. All patients were evaluated with shoulder radiographs, Constant and Murley Scores, UCLA Shoulder Score, visual analog pain score, range of motion, and the Short Shoulder Form. Modest improvement was noted in forward flexion and abduction. Significant improvement was noted in shoulder function. Transfer of the latissimus dorsi as salvage for a previously failed repair of a massive rotator cuff tear is effective in providing pain relief and improving shoulder function.

Characterization of a consistent radiographic finding in chronic anterior cruciate ligament deficiency: the posteromedial osteophyte.

Often found in patients undergoing total knee arthroplasty (TKA) is an osteophyte, at the posterior lateral corner of the medial tibial plateau, that prevents anterior translation. This osteophyte does not occur in the presence of an entirely normal anterior cruciate ligament (ACL) with normal vascularity. Although similar findings have been reported in animal studies, to our knowledge this has never been documented in humans. To determine the incidence of this finding in our patient population, anteroposterior and lateral x-rays of the affected knee of 90 patients undergoing TKA were reviewed. Forty-two percent (43/102 knees) had radiographic signs of this stabilizing osteophyte. This finding confirms previous animal research and may lead to a better understanding of how the knee adapts to improve stability in a chronic ACL-deficient state.

Electrothermal arthroscopic shoulder capsulorrhaphy: a minimum 2-year follow-up.

BACKGROUND: Few studies have documented the outcomes of thermal capsulorrhaphy for shoulder instability. PURPOSE: To examine prospective evaluate outcomes of the first 100 patients with glenohumeral instability treated with thermal capsulorrhaphy. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1997 and 1999, 85 of 100 patients treated with thermal capsulorrhaphy for glenohumeral instability were available for review at 2-year minimum follow-up (average, 4 years). Fifty-one patients suffered from anterior instability; 24 had an associated Bankart lesion. Ten patients demonstrated posterior instability; 1 had an associated reverse Bankart lesion. Seventeen patients had multidirectional instability; 8 had an associated Bankart lesion. Seven patients demonstrated anterior and posterior instability without an inferior component; 2 had an associated Bankart lesion. Failures were defined as shoulders requiring revision stabilization (14) or with recurrent instability (18), recalcitrant pain (3), or stiffness (2). RESULTS: Forty-eight of 85 procedures were successful, and 37 of 85 failed. For patients with anterior instability plus a Bankart lesion, 7 of 24 (26%) had failed results. For those with anterior instability without a Bankart lesion, 10 of 27 (33%) had failed results. The failure rates for posterior, multidirectional instability, and anteroposterior were 60% (6/10), 59% (10/17), and 57% (4/7), respectively. Of the 48 successes, mean preoperative American Shoulder and Elbow Surgeons score improved from 71 to 96 postoperatively, and patient satisfaction was 9.1 on a 10-point scale. CONCLUSION: Because of the high failure rates, we now augment thermal capsulorrhaphy with capsular plication and/or rotator interval closure in cases of posterior and multidirectional instability and have lengthened the initial immobilization period to improve outcomes. Failure rates for thermal capsulorrhaphy, even with labral repairs, are high especially for shoulders with multidirectional instability and posterior instability. When procedures were successful, however, patients were very satisfied with significant improvements in American Shoulder and Elbow Surgeons scores.

A biomechanical comparison of EndoButton versus suture anchor repair of distal biceps tendon injuries.

The purpose of this study was to compare suture anchor and EndoButton repair of distal biceps injuries in a human bone-tendon model. Right and left arm repairs were alternately performed with either the EndoButton or 2 single-loaded 5-mm suture anchors. Each construct was cyclically loaded by use of a servohydraulic materials testing machine. Initial and final displacements were recorded. All repairs were then loaded to ultimate failure. Ten millimeters of displacement was designated the clinical failure point. The EndoButton group had more stiffness than the suture anchor group during initial cyclic loading (P = .01). There were no differences in final displacement measured after cyclic loading (2.06 mm for suture anchors and 2.58 mm for EndoButton). The EndoButton group had a 16% greater ultimate tensile load than the suture anchor group (274.77 N vs 230.06 N). The EndoButton group also had a 16% higher load to clinical failure (249.95 N vs 209.56 N). These differences were not statistically significant. The EndoButton and suture anchors provide comparable fixation strength for the repair and rehabilitation of distal biceps tendon ruptures.

Scapular kinematics during supraspinatus rehabilitation exercise: a comparison of full-can versus empty-can techniques.

BACKGROUND: Supraspinatus strengthening is an important component of shoulder rehabilitation. Previous work has determined that the full-can and empty-can exercises elicit the greatest amount of supraspinatus activity. However, scapular kinematics has not been considered when prescribing supraspinatus exercises. HYPOTHESIS: Scapular downward rotation, internal rotation, and anterior tipping during the empty-can exercise are increased when compared with the full-can exercise. STUDY DESIGN: Descriptive laboratory study. METHODS: Twenty participants performed full-can and empty-can exercises while an electromagnetic tracking system was used to collect three-dimensional scapular kinematic data. Scapular angles at 30 degrees, 60 degrees, and 90 degrees of the ascending and descending phases of humeral elevation were compared using 2-way repeated measures analysis of variance. RESULTS: There was more scapular anterior tipping and internal rotation during the empty-can exercise at all sampled humeral elevation angles except at 30 degrees of the descending phase for anterior/posterior tipping (P < .05). CONCLUSION: Scapular anterior tipping and internal rotation are increased during the empty-can exercise, whereas scapular upward rotation was not different between exercises. CLINICAL RELEVANCE: Increased scapular internal rotation and anterior tipping decrease the volume of the supraspinatus outlet during the empty-can exercise. When maintenance of the subacromial space is important, use of the full-can exercise seems most appropriate for selective strengthening of the supraspinatus muscle.

Suture plication, thermal shrinkage, and sclerosing agents: effects on rat patellar tendon length and biomechanical strength.

BACKGROUND: Shortening or tightening of dense, collagenous tissues is often desirable in the treatment of laxity. PURPOSE: To compare the effect of stress-protection suture, radiofrequency thermal shrinkage combined with stress-protection suture, and a 5% sodium morrhuate sclerosing injection on the length and biomechanical strength of the rat patellar tendon. HYPOTHESIS: Sclerosing agents will increase tendon mechanical strength. Thermal shrinkage combined with stress-protection suture and stress-protection suture only will cause a short-term decrease in tendon strength. All 3 methods will produce equivalent shortening of the tendon. STUDY DESIGN: Controlled laboratory study. METHODS: Forty-six female retired breeder rats were split into 4 groups, each receiving 1 of the 3 aforementioned treatments plus a control group that received a saline injection. After 4 weeks' survival, the length and biomechanical properties of the patellar tendons were measured and compared to the contralateral untreated tendon. RESULTS: Rats treated with stress-protection suture had shorter tendons. Radiofrequency thermal shrinkage combined with stress-protection suture yielded tendons that were both shorter and stronger than were the untreated contralateral tendons. The sodium morrhuate-injected tendons were stronger whereas the saline-treated tendons were weaker than were their respective untreated contralateral tendons. CONCLUSION: Surgical stress-protection suture without radiofrequency shrinkage is most effective at shortening the length of the rat patellar tendon, whereas radiofrequency thermal shrinkage combined with stress-protection suture as well as sodium morrhuate are effective at increasing the strength of rat patellar tendons. CLINICAL RELEVANCE: Judicious use of thermal shrinkage in combination with stress protection may improve ligament strength and decrease laxity.

The HAGL lesion: an arthroscopic technique for repair of humeral avulsion of the glenohumeral ligaments.

Glenoid avulsion of the capsulolabral complex and associated capsular laxity are well-described results of traumatic anterior dislocation. A less common consequence of traumatic anterior instability is the humeral avulsion of the glenohumeral ligaments (HAGL) lesion. An understanding of the arthroscopic pathoanatomy of the HAGL lesion will assist the surgeon in recognizing this uncommon entity. We describe a suture anchor technique for arthroscopic repair of HAGL lesions that anatomically reapproximates the torn edge of the glenohumeral ligament complex to its humeral head insertion. The technique is technically straightforward and does not require special equipment beyond that typical for arthroscopic labral repairs.

The repeatability of scapular rotations across three planes of humeral elevation.

Measurement of scapular kinematics is an important component in the assessment of shoulder function; however, repeatability of these measurements has not been established. The purpose of this study, therefore, was to determine the repeatability of scapular rotation measures for different humeral elevation planes between trials, sessions, and days. Three-dimensional scapular rotations were collected using an electromagnetic tracking system in three planes of humeral elevation. Coefficient of multiple correlation (CMC) values were calculated between trials, sessions, and days for curves of scapular rotations. CMC values were compared with repeated measures analysis of variance (ANOVAs) and Tukey's post-hoc procedures. Tests of simple main effects were performed for significant interaction effects. Our results suggest that scapular rotation measures are repeatable between trials within the same testing session, but less repeatable between testing sessions and days. Sagittal plane elevation consistently yielded the highest CMC values for all scapular rotations. These results suggest sagittal plane elevation should be considered to evaluate differences in scapular rotations.

Thermal microdebridement does not affect the time zero biomechanical properties of human patellar tendons.

BACKGROUND: Thermal microdebridement for the treatment of chronic tendinopathy has recently been introduced. The effect of thermal microdebridement on the biomechanical properties of human tendons, however, remains unknown. HYPOTHESIS: Thermal microdebridement does not affect the biomechanical properties of human patellar tendons in a cadaveric model at the time of initial treatment. STUDY DESIGN: Controlled laboratory study. METHODS: The central 15 mm of 12 matched, human (mean age, 71 years; 8 male, 4 female), fresh-frozen patellar tendons was divided into 3 equal 5-mm specimens. The treatment group (n = 12) underwent thermal microdebridement with a radiofrequency probe. A sham treatment group (n = 12) underwent insertion of a deactivated probe. The control group (n = 12) underwent no treatment. After treatment, each specimen was tested to failure in a servo-hydraulic materials testing machine at an elongation rate of 3 mm/s. One-way repeated measures analysis of variance was used to determine differences between groups. RESULTS: No significant difference in ultimate stress at failure, elastic modulus, strain energy density, or strain at maximum load was found between the groups. The ultimate stress at failure for the treatment, sham, and control groups was 61.0, 66.7, and 63.0 MPa, respectively (P = .653), and the strain at maximum load was 0.12, 0.11, and 0.09, respectively (P = .279). CONCLUSIONS: Thermal microdebridement does not affect the biomechanical properties of cadaveric human patellar tendons at the time of initial treatment. CLINICAL RELEVANCE: It may be safe to proceed with aggressive rehabilitation after thermal microdebridement of the patellar tendon. However, the results in this cadaveric model should be interpreted with caution. Additional studies using an in vivo model will be required to completely assess the effects of thermal microdebridement on the biomechanical properties of human patellar tendons.