Locally applied heat stress during exercise training may promote adaptations to mitochondrial enzyme activities in skeletal muscle.

There is some evidence for temperature-dependent stimulation of mitochondrial biogenesis; however, the role of elevated muscle temperature during exercise in mitochondrial adaptation to training has not been studied in humans in vivo. The purpose of this study was to determine the role of elevating muscle temperature during exercise in temperate conditions through the application of mild, local heat stress on mitochondrial adaptations to endurance training. Eight endurance-trained males undertook 3 weeks of supervised cycling training, during which mild (~ 40 °C) heat stress was applied locally to the upper-leg musculature of one leg during all training sessions (HEAT), with the contralateral leg serving as the non-heated, exercising control (CON). Vastus lateralis microbiopsies were obtained from both legs before and after the training period. Training-induced increases in complex I (fold-change, 1.24 ± 0.33 vs. 1.01 ± 0.49, P = 0.029) and II (fold-change, 1.24 ± 0.33 vs. 1.01 ± 0.49, P = 0.029) activities were significantly larger in HEAT than CON. No significant effects of training, or interactions between local heat stress application and training, were observed for complex I-V or HSP70 protein expressions. Our data provides partial evidence to support the hypothesis that elevating local muscle temperature during exercise augments training-induced adaptations to mitochondrial enzyme activity.

Durability of the moderate-to-heavy-intensity transition is related to the effects of prolonged exercise on severe-intensity performance.

PURPOSE: Power output at the moderate-to-heavy-intensity transition decreases during prolonged exercise, and resilience to this has been termed 'durability'. The purpose of this study was to assess the relationship between durability and the effect of prolonged exercise on severe-intensity performance, and explore intramuscular correlates of durability. METHODS: On separate days, 13 well-trained cyclists and triathletes (V̇O2peak, 57.3 ± 4.8 mL kg-1 min-1; training volume, 12 ± 2.1 h week-1) undertook an incremental test and 5-min time trial (TT) to determine power output at the first ventilatory threshold (VT1) and severe-intensity performance, with and without 150-min of prior moderate-intensity cycling. A single resting vastus lateralis microbiopsy was obtained. RESULTS: Prolonged exercise reduced power output at VT1 (211 ± 40 vs. 198 ± 39 W, ∆ -13 ± 16 W, ∆ -6 ± 7%, P = 0.013) and 5-min TT performance (333 ± 75 vs. 302 ± 63 W, ∆ -31 ± 41 W, ∆ -9 ± 10%, P = 0.017). The reduction in 5-min TT performance was significantly associated with durability of VT1 (rs = 0.719, P = 0.007). Durability of VT1 was not related to vastus lateralis carnosine content, citrate synthase activity, or complex I activity (P > 0.05). CONCLUSION: These data provide the first direct support that durability of the moderate-to-heavy-intensity transition is an important performance parameter, as more durable athletes exhibited smaller reductions in 5-min TT performance following prolonged exercise. We did not find relationships between durability and vastus lateralis carnosine content, citrate synthase activity, or complex I activity.

Skeletal muscle proteins involved in fatty acid transport influence fatty acid oxidation rates observed during exercise.

Several proteins are implicated in transmembrane fatty acid transport. The purpose of this study was to quantify the variation in fatty acid oxidation rates during exercise explained by skeletal muscle proteins involved in fatty acid transport. Seventeen endurance-trained males underwent a (i) fasted, incremental cycling test to estimate peak whole-body fatty acid oxidation rate (PFO), (ii) resting vastus lateralis microbiopsy, and (iii) 2 h of fed-state, moderate-intensity cycling to estimate whole-body fatty acid oxidation during fed-state exercise (FO). Bivariate correlations and stepwise linear regression models of PFO and FO during 0-30 min (early FO) and 90-120 min (late FO) of continuous cycling were constructed using muscle data. To assess the causal role of transmembrane fatty acid transport in fatty acid oxidation rates during exercise, we measured fatty acid oxidation during in vivo exercise and ex vivo contractions in wild-type and CD36 knock-out mice. We observed a novel, positive association between vastus lateralis FATP1 and PFO and replicated work reporting a positive association between FABPpm and PFO. The stepwise linear regression model of PFO retained CD36, FATP1, FATP4, and FABPpm, explaining ~87% of the variation. Models of early and late FO explained ~61 and ~65% of the variation, respectively. FATP1 and FATP4 emerged as contributors to models of PFO and FO. Mice lacking CD36 had impaired whole-body and muscle fatty acid oxidation during exercise and muscle contractions, respectively. These data suggest that substantial variation in fatty acid oxidation rates during exercise can be explained by skeletal muscle proteins involved in fatty acid transport.

The posterior crescent sign on MRI and MR arthrography: is it a marker of hip dysplasia and instability?

OBJECTIVE: To evaluate the prevalence of the 'posterior crescent sign' in symptomatic patients referred for MRI/MR arthrogram of the hip and identify any correlation with imaging features of joint pathology. MATERIALS AND METHODS: Retrospective imaging assessment of a cohort of 1462 hips, from 1380 included MR examinations (82 bilateral) retrieved from a search of all examinations in patients 16-50 years old from June 2018 to June 2021, with median age 45.8 years (range 17.8-50.0) and 936 hips (64%) in women. Radiographic and MR findings related to hip dysplasia, femoroacetabular impingement and osteoarthritis were assessed. RESULTS: Fifty-one hips (3.5%) were positive for the posterior crescent sign, median age of 45.8 years (range 17.8-50.0) and 29 (58%) in women. Radiographic findings included the following: mean lateral centre edge angle (LCEA) 22.2° (± 7.8°) with LCEA < 20° in 15 (31%) and LCEA 20-25° in 17 (35%) and mean acetabular index (AI) of 13.1° (± 5.8°) with AI > 13° in 22 (45%). MR findings included the following: mean anterior acetabular sector angle (AASA) 54.3° (± 9.8°), mean posterior acetabular sector angle (PASA) 92.7° (± 7.0°), labral tear at 3-4 o'clock in 20 (39%), high-grade acetabular chondral loss in 42 (83%) and ligamentum teres abnormality in 20 (39%). CONCLUSION: The posterior crescent sign occurs in 3.5% of symptomatic young and middle-aged adults on MR. It is associated with overt and borderline hip dysplasia and other findings of hip instability. It is also associated with osteoarthritis in some cases and should be interpreted with caution in these patients.

Peak fat oxidation is positively associated with vastus lateralis CD36 content, fed-state exercise fat oxidation, and endurance performance in trained males.

PURPOSE: Whole-body fat oxidation during exercise can be measured non-invasively during athlete profiling. Gaps in understanding exist in the relationships between fat oxidation during incremental fasted exercise and skeletal muscle parameters, endurance performance, and fat oxidation during prolonged fed-state exercise. METHODS: Seventeen endurance-trained males underwent a (i) fasted, incremental cycling test to assess peak whole-body fat oxidation (PFO), (ii) resting vastus lateralis microbiopsy, and (iii) 30-min maximal-effort cycling time-trial preceded by 2-h of fed-state moderate-intensity cycling to assess endurance performance and fed-state metabolism on separate occasions within one week. RESULTS: PFO (0.58 ± 0.28 g.min-1) was associated with vastus lateralis citrate synthase activity (69.2 ± 26.0 µmol.min-1.g-1 muscle protein, r = 0.84, 95% CI 0.58, 0.95, P < 0.001), CD36 abundance (16.8 ± 12.6 µg.g-1 muscle protein, rs = 0.68, 95% CI 0.31, 1.10, P = 0.01), pre-loaded 30-min time-trial performance (251 ± 51 W, r = 0.76, 95% CI 0.40, 0.91, P = 0.001; 3.2 ± 0.6 W.kg-1, r = 0.62, 95% CI 0.16, 0.86, P = 0.01), and fat oxidation during prolonged fed-state cycling (r = 0.83, 95% CI 0.57, 0.94, P < 0.001). Addition of PFO to a traditional model of endurance (peak oxygen uptake, power at 4 mmol.L-1 blood lactate concentration, and gross efficiency) explained an additional ~ 2.6% of variation in 30-min time-trial performance (adjusted R2 = 0.903 vs. 0.877). CONCLUSION: These associations suggest non-invasive measures of whole-body fat oxidation during exercise may be useful in the physiological profiling of endurance athletes.

Criteria for the Operating Room Confirmation of the Diagnosis of Hip Instability: The Results of an International Expert Consensus Conference.

PURPOSE: The purpose of this study was to establish an international expert consensus on operating room findings that aid in the diagnosis of hip instability. METHODS: An expert panel was convened to build an international consensus on the operating room diagnosis/confirmation of hip instability. Seventeen surgeons who have published or lectured nationally or internationally on the topic of hip instability were invited to participate. Fifteen panel members completed a pre-meeting questionnaire and agreed to participate in a 1-day consensus meeting on May 15, 2021. A review of the literature was performed to identify published intraoperative reference criteria used in the diagnosis of hip instability. Studies were included for discussion if they reported and intraoperative findings associated with hip instability. The evidence for and against each criteria was discussed, followed by an anonymous voting process. For consensus, defined a priori, items were included in the final criteria set if at least 80% of experts agreed. RESULTS: A review of the published literature identified 11 operating room criteria that have been used to facilitate the diagnosis of hip instability. Six additional criteria were proposed by panel members as part of the pre-meeting questionnaire. Consensus agreement was achieved for 8 criteria, namely ease of hip distraction under anesthesia (100.0% agreement), inside-out pattern of chondral damage (100.0% agreement), location of chondral damage on the acetabulum (93.3% agreement), pattern of labral damage (93.3% agreement), anteroinferior labrum chondral damage (86.7% agreement), perifoveal cartilage damage (97.6% agreement), a capsular defect (86.7% agreement), and capsular status (80.0% agreement). Consensus was not achieved for 9 items, namely ligamentum teres tear (66.7% agreement), arthroscopic stability tests (46.7% agreement), persistent distraction after removal of traction (46.7% agreement), findings of examination under anesthesia (46.7% agreement), the femoral head divot sign (40.0% agreement), inferomedial synovitis (26.7% agreement), drive-through sign (26.7% agreement), iliopsoas irritation (26.7% agreement) and ligamentum teres-labral kissing lesion (13.3% agreement). All experts agreed on the final list of 8 criteria items reaching consensus. CONCLUSION: This expert panel identified 8 criteria that can be used in the operating room to help confirm the diagnosis of hip instability. LEVEL OF EVIDENCE: Level V expert opinion.

Microinstability of the hip: a systematic review of the imaging findings.

OBJECTIVES: To undertake a systematic review of the morphologic features associated with hip microinstability and determine whether there are suggestive or diagnostic imaging findings. METHODS: Four electronic databases were searched up to September 2019 to identify original research reporting morphologic features in individuals with either a clinical diagnosis of hip microinstability (instability without overt subluxation/dislocation) or those with symptomatic laxity demonstrated on imaging (increased femoral head translation/distraction or capsular volume). Studies focussing on individuals with pre-existing hip conditions (including definite dysplasia (lateral centre edge angle < 20°), significant trauma, previous dislocation or surgery were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool. RESULTS: Twenty-two studies met inclusion criteria (clinical diagnosis of microinstability n = 15 and demonstration of laxity n = 7). Imaging information gathered from the studies includes radiographs (n = 14), MRI (n = 6), MR arthrography (n = 4), CT (n = 1) and intraoperative examination. Most studies exhibited design features associated with an overall high or unclear risk of bias. Some dysplastic features are associated with microinstability or laxity reference measures; however, microinstability is frequently diagnosed in those with a lateral centre edge angle > 25°. Other associated imaging findings reported include impingement morphology, anterior labral tearing, femoral head chondral injury, ligamentum teres tears and capsular attenuation. CONCLUSIONS: The current literature does not provide strong evidence for imaging features diagnostic of microinstability. In the appropriate clinical context, dysplastic morphology, anterior labral tears and ligamentum teres tears may be suggestive of this condition although further research is needed to confirm this. PROSPERO REGISTRATION: CRD42019122406.

Medium-term outcomes of a cohort of revision rotator cuff repairs.

BACKGROUND: There are limited medium- and long-term studies investigating clinical outcomes following revision rotator cuff surgery. The aim of the current study was to analyze the medium-term pain and functional outcomes of a cohort of revision rotator cuff repairs. METHODS: This was a multicenter, prospective cohort study of revision rotator cuff repairs undertaken between March 2009 and December 2010. Pain, function (Flex-SF), and postoperative data were collected at baseline; 6, 12, and 24 months; and 5 years. RESULTS: A total of 125 revision rotator cuff repairs were included in this study. Average improvement in Flex-SF and pain from baseline to 5 years was 8.5 (P < .001) and 2.1 points, respectively (P < .001). The improvement was not as pronounced as those who underwent primary repair. Significantly lower pain scores were seen in nonsmokers (P < .001) and in those who underwent tenotomy rather than tenodesis (2 vs. 3.5, P < .05) for a damaged long head of biceps. Significantly higher function scores were seen in those with only 1 tendon involved (P < .05). The patient-reported retear rate was 32.6%, and the reoperation rate was 34.7%. CONCLUSION: Revision rotator cuff repair provides significant improvement in both pain and function at 5 years postoperation, though not as good as primary repair. Superior clinical outcomes are seen in nonsmokers, those with only 1 tendon affected, and those who undergo tenotomy instead of tenodesis for a damaged long head of biceps tendon.

Bilateral hip arthroscopy under the same anesthetic for patients with symptomatic bilateral femoroacetabular impingement: 1-year outcomes.

PURPOSE: The purpose of this study was to investigate whether, in patients with bilateral symptomatic femoroacetabular impingement, bilateral surgery under 1 anesthetic is safe and efficacious and allows a rapid return of function compared with staged procedures. METHODS: Three groups were evaluated: in group 1 both hips were treated simultaneously, in group 2 both hips were treated in a staged fashion, and in group 3 a single hip was addressed. The outcome measures were anesthesia and surgical times; time in the hospital; visual analog scale score for pain on postoperative days 1, 3, 7, and 30; analgesic use; and time until the patient could bike, drive, perform office work, perform gym activities, run, and return to play. Midterm evaluation was performed with the Non-Arthritic Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index score at 6 and 12 months postoperatively. RESULTS: We enrolled 76 patients (122 hips) in this study. There were 42 male and 34 female patients. The mean age was 33 years (range, 14 to 50 years), and the mean body mass index was 24 (range, 18 to 35). Group 1 comprised 26 patients (52 hips, 16 male and 10 female patients). Group 2 comprised 20 patients (40 hips, 13 male and 7 female patients), with a mean time between surgeries of 14.56 weeks. Group 3 comprised 33 patients (30 hips, 13 male and 17 female patients). No preoperative differences were found between the groups. The surgical and anesthesia times in group 1 were significantly longer than those in groups 2 and 3. We found no significant differences in postoperative visual analog scale scores, analgesic use, or length of hospital stay. Group 1 required more time before patients were able to ride a stationary bicycle (14.7 days in group 1, 7.8 days in group 2, and 8.5 days in group 3; P < .05). We found no differences between the groups regarding when patients returned to driving, performing office work, or reporting a normal gait. Each group had significant improvements in the Western Ontario and McMaster Universities Osteoarthritis Index and Non-Arthritic Hip Score at 6 and 12 months compared with preoperatively (P < .05). No significant differences in outcome scores were found in the 3 groups before surgery and at 6 or 12 months after surgery. CONCLUSIONS: Simultaneous femoroacetabular impingement surgery does not lead to higher rates of complications, postoperative pain, analgesic use, or side effects. The return to daily activities is similar to a single-hip procedure with the advantage of a single rehabilitation. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Catastrophic failure of hip arthroscopy due to iatrogenic instability: can partial division of the ligamentum teres and iliofemoral ligament cause subluxation?

Hip arthroscopy is an evolving surgical tool, and with any new procedure, it is important to learn from the complications encountered. A patient with mild hip dysplasia and a symptomatic labral tear underwent uneventful hip arthroscopy and labral repair including partial debridement of a hypertrophied ligamentum teres. Despite preservation of the labrum, no pincer resection, and a modest capsulotomy, 3 months, subluxation and joint space narrowing were noted. One year, end-stage arthritis was present, requiring total hip replacement. Instability after hip arthroscopy is due to a number of factors, including excessive rim trimming, capsulotomy, overzealous labral resection, or inadequate labral repair. This report emphasizes the importance of the ligamentum teres and small disruptions of the capsule in patients with mild dysplasia.

Ligamentum Teres Lesions Are Associated With Poorer Patient Outcomes in a Large Primary Hip Arthroscopy Cohort of 1,935 Patients.

Purpose: To retrospectively evaluate the prevalence and characteristics of ligamentum teres (LT) lesions identified in a single-surgeon hip arthroscopy cohort and to compare surgical outcomes of those with, and without, identified LT lesions. Methods: Patients who underwent primary hip arthroscopy between 2005 and 2018 in one surgeon's clinic were identified. Those with a history involving extra-articular scoping or any previous surgery on the ipsilateral hip were excluded. Patient-reported outcome measures completed before and after surgery included the Hip Disability and Osteoarthritis Outcome Score, Nonarthritic Hip Score, and 12-item International Hip Outcome Tool. Conversion to hip joint replacement was ascertained through a national register. Results: A total of 1,935 primary hip arthroscopies (from 1,607 different patients) were included in this study. In total, 323 LT lesions were identified. Those with LT lesions were older than those without (40.3 ± 11.3 years compared with 33.9 ± 12.1 years; P < .001), and more frequently female (58.2% vs 41.8%; P = .001). Hips with lesions had a smaller lateral center-edge angle than other hips (33.0 ± 6.8° vs 34.1 ± 6.0°; P = .004). All patient-reported outcome measures improved significantly (P < .001) from pre- to post-surgery for patients with and without LT lesions. However, patients with LT lesions reported less improvement in the 12-item International Hip Outcome Tool (difference -5.60; P = .004) and in Hip Disability and Osteoarthritis Outcome Score symptoms (-4.41; P = .004), sports (-7.81; P < .001), and quality of life subscales (-8.85; P < .001) than those without lesions. Hips with LT lesions also had a 6.2% 2-year rate of subsequent hip replacement (20/323 hips) compared with those without lesions (0.9%; 14/1612 hips; P < .001). Conclusions: In this single-surgeon hip arthroscopy cohort, identification of LT lesions was associated with poorer patient-reported outcomes and increased likelihood of conversion to arthroplasty within 2 years. These findings suggest a poorer prognosis for patients with LT injury compared with those without. Level of Evidence: Level III, retrospective cohort study.

Do Age, Demographics, and Tear Characteristics Affect Outcomes After Rotator Cuff Repair? Results of Over 2000 Rotator Cuff Repairs at 5-Year Follow-up.

Background: The New Zealand Rotator Cuff Registry represents the largest prospective cohort of rotator cuff repairs. Despite this, there are limited medium- to long-term data of rotator cuff repair outcomes. Purpose: To (1) analyze the pain and functional outcomes of a large cohort of primary rotator cuff repairs and (2) evaluate the effect of patient factors and tear characteristics on medium-term outcomes. Study Design: Cohort study; Level of evidence, 2. Methods: This was a multicenter, multisurgeon prospective cohort study of rotator cuff repairs from March 2009 until December 2010. Surgical data were collected by the operating surgeon. Primary outcome measures were the Flexilevel Scale of Shoulder Function (FLEX-SF) and a pain score, collected at baseline, 6, 12, and 24 months, and 5 years. Univariate and multivariate analyses were carried out. Results: Overall, 2533 primary rotator cuff repairs were analyzed with 81% follow-up at 5 years. The mean age of the cohort was 56 years. In the 2052 patients with final follow-up data, improvement on the FLEX-SF continued until 24 months postoperatively and remained high at 5 years. Mean improvement in FLEX-SF from baseline to 5 years was 15 points. Patients aged >70 years had lower FLEX-SF scores but no significant difference in improvement compared with patients ≤70 years. The mean anteroposterior tear size was 2.2 cm, and on multivariate analysis, tears >4 cm had worse 5-year FLEX-SF scores. If the affected tendon was easily reducible, there was no difference in FLEX-SF score for retracted or larger tears compared with smaller tears. The reoperation rate was 6.2%. Conclusion: Results indicated that rotator cuff repairs provide a sustained clinical improvement out past 5 years. Most functional improvement and pain relief occurred within the first 6 months, but improvement continued out to 24 months. Most population groups did well after rotator cuff repairs, including those >70 years. Tear size >4 cm and tendon reducibility correlated with outcome. Even patients with large tear sizes had clinically significant improvement in FLEX-SF scores after repair.

Pre-existing osteoarthritis remains a key feature of arthroscopy patients who convert to total hip arthroplasty.

OBJECTIVES: To determine the rate of conversion to total hip arthroplasty following ipsilateral hip arthroscopy by a single surgeon in New Zealand and to describe patient-related and surgical characteristics of patients who converted. METHODS: A retrospective cohort analysis of hip arthroscopy patients with 2 years of minimum follow-up identified the total hip arthroplasty conversion rate using the New Zealand National Joint Registry. Prospective data collected from patients who subsequently converted to hip arthroplasty included: sex, age at arthroscopy, body mass index, side of hip arthroscopy and arthroplasty, duration of symptoms and patient-reported outcome measures. Imaging (Tönnis grade and lateral centre-edge angle) and surgical findings (labral, ligamentum teres and osteochondral pathology) along with the arthroscopic procedures performed were also documented. RESULTS: Sixty-six out of 1856 (3.56%) primary hip arthroscopies were followed by an ipsilateral hip arthroplasty during the follow-up period (mean 87 ± 29 months). Most patients had pre-existing osteoarthritis and/or chondral lesions (n=51). Dysplasia and over-resection of the acetabulum were also identified as contributing factors. CONCLUSION: Conversion rate by a high-volume surgeon in New Zealand was relatively low. Most patients had pre-existing osteoarthritis and/or chondral lesions that became apparent at arthroscopy. Dysplasia is also a factor to be cautious of when selecting patients for arthroscopy. Acetabular resection must be approached cautiously. LEVEL OF EVIDENCE: Level IV.

Graft Options in Hip Labral Reconstruction.

PURPOSE OF REVIEW: The last decade has seen a boom in hip arthroscopy with refined indications. Improved understanding of pathoanatomy and disease progression has allowed for the development of advanced techniques. Labral reconstruction has been developed to substitute a non-functional or absent labrum. It has become an important technique in the armamentarium of high-volume arthroscopic hip surgeons. RECENT FINDINGS: Basic science studies have improved understanding of hip biomechanics in the presence and absence of a labrum with a labral reconstruction allowing for reconstitution of normalcy. Current techniques have shown success with autograft and allograft tissue options. While autograft tissue allows for easy access intra-operatively and maintains patient biology, donor site morbidity is possible. Allografts negate donor site morbidity and allow for an abundance of tissue but can be resource-intensive and face availability concerns. Recent studies support outcomes of labral reconstructions using both autograft and allograft. Promising results have also allowed for performing labral reconstruction in a primary setting. Labral reconstruction can be successfully performed using both autograft and allograft. Patient biology should be respected, and native hip biomechanics restored. The literature is plentiful for appropriate surgical decision-making allowing the surgeon with multiple graft choices depending on training, experience, and resources.

Peri-operative platelet-rich plasma in arthroscopic femoroacetabular impingement surgery: a randomized controlled trial.

This study aimed to determine whether the addition of platelet-rich plasma (PRP) during hip arthroscopy improves functional outcomes in femoroacetabular impingement (FAI) surgery. This was a prospective randomized single-blinded trial of arthroscopic hip patients aged between 16 and 50 years with a diagnosis of FAI conducted at a single centre. Patients with any previous hip surgery and significant osteoarthritic changes (Tonnis grade > 2) were excluded. Before surgery, patients were randomly assigned to receive either a PRP injection or a saline placebo. Efficacy was evaluated at 6 months, 1 year and 2 years post-surgery using patient-reported outcomes. The short version International Hip Outcome Tool (iHOT12) was the primary outcome. Recruited patients (n = 113) were aged 36.0 ± 10.5 (mean ± standard deviation) years and 56% male. At baseline, iHOT12 scores of the PRP (mean 43.8 ± 22.4) and placebo groups (mean 45.2 ± 21.5) were similar. At a minimum follow-up of 2 years, both groups had improved iHOT12 scores (PRP: mean 83.6 ± 13.4, control: mean 77.1 ± 23.3), with no significant difference in change between the two groups (P = 0.19). There were no significant group differences for the change in Non-Arthritic Hip and Hip Disability and Osteoarthritis Outcome Score-Shortform scores between the two groups (P = 0.22 and 0.46, respectively). The present study does not support the peri-operative use of PRP in arthroscopic surgery for FAI for mid-term improvement. There were no significant differences in outcome between PRP and placebo groups at 2-year minimum follow-up after surgery.

Impact of smoking on pain and function in rotator cuff repair: a prospective 5-year cohort follow-up of 1383 patients.

BACKGROUND: This multicentre cohort study investigates the effect of smoking on the outcome of rotator cuff repair (RCR), with attention to age at presentation for surgery, pre-operative and post-operative pain and function and intra-operative findings. METHODS: Patient information was collected pre-operatively, including Flex Shoulder Function (Flex SF) and visual analogue scale pain, then at 6 months, 1, 2 and 5 years post-operatively. Intra-operative technical data were collected by the operating surgeon. Current smokers were classified by daily cigarette consumption. RESULTS: A total of 1383 RCRs in as many patients were included with an 84% 5-year follow-up. Smokers were on average 6.7 years younger than non-smokers (51.8 vs. 58.5, P < 0.001). There was no difference in intra-operatively assessed tear size both in anteroposterior dimension (P = 0.5) and retraction (P = 0.9). Pre-operative Flex SF score in smokers was below that of non-smokers (23.0 vs. 24.5, P = 0.002) and at 6 months (P = 0.02) but no different at 5 years (P = 0.7). Pain scores were higher in smokers than non-smokers both pre-operatively (5.34 vs. 4.67, P < 0.001) and up to 2 years (P < 0.001) but not at 5 years (P = 0.073). CONCLUSION: Smokers undergoing RCR were younger than non-smokers, and had worse pre-operative pain scores and shoulder function. Poorer post-operative function persisted to 6 months, and with higher reported pain to 2 years in smokers. However, at 5-year follow-up, patient-reported outcomes were not affected by smoking status.

Temperate performance and metabolic adaptations following endurance training performed under environmental heat stress.

Endurance athletes are frequently exposed to environmental heat stress during training. We investigated whether exposure to 33°C during training would improve endurance performance in temperate conditions and stimulate mitochondrial adaptations. Seventeen endurance-trained males were randomly assigned to perform a 3-week training intervention in 18°C (TEMP) or 33°C (HEAT). An incremental test and 30-min time-trial preceded by 2-h low-intensity cycling were performed in 18°C pre- and post-intervention, along with a resting vastus lateralis microbiopsy. Training was matched for relative cardiovascular demand using heart rates measured at the first and second ventilatory thresholds, along with a weekly "best-effort" interval session. Perceived training load was similar between-groups, despite lower power outputs during training in HEAT versus TEMP (p < .05). Time-trial performance improved to a greater extent in HEAT than TEMP (30 ± 13 vs. 16 ± 5 W, N = 7 vs. N = 6, p = .04), and citrate synthase activity increased in HEAT (fold-change, 1.25 ± 0.25, p = .03, N = 9) but not TEMP (1.10 ± 0.22, p = .22, N = 7). Training-induced changes in time-trial performance and citrate synthase activity were related (r = .51, p = .04). A group × time interaction for peak fat oxidation was observed (Δ 0.05 ± 0.14 vs. -0.09 ± 0.12 g·min-1 in TEMP and HEAT, N = 9 vs. N = 8, p = .05). Our data suggest exposure to moderate environmental heat stress during endurance training may be useful for inducing adaptations relevant to performance in temperate conditions.

Importance of Retaining Sufficient Acetabular Depth: Successful 2-Year Outcomes of Hip Arthroscopy for Patients With Pincer Morphology as Compared With Matched Controls.

BACKGROUND: Patients with pincer-type femoroacetabular impingement are commonly treated with arthroscopic reduction of acetabular depth as measured by the lateral center-edge angle (LCEA). The optimal amount of rim reduction has not been established, although large resections may increase contact pressures through the hip. A recent publication demonstrated inferior surgical outcomes in patients with acetabular overcoverage as compared with normal acetabular coverage. Casual observation of our database suggested equivalent improvements, prompting a similar analysis. PURPOSE: To analyze patient-reported outcomes after hip arthroscopy for femoroacetabular impingement in patients with acetabular overcoverage who were matched with controls with normal coverage, as well as to analyze associations with reduction in LCEA. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were collected prospectively from patients with a minimum 2-year follow-up after receiving hip arthroscopy for femoroacetabular impingement by a single surgeon. Cases were reviewed to identify those with pincer-type morphology (LCEA >40°) and matched according to sex, age, chondral damage, and surgery date in a 1:1 ratio with controls with an LCEA of 25° to 40°. The surgical goal was to reduce the LCEA to the upper end of the normal range with minimal rim resection, usually 35° to 37°. Radiographic measurements of coverage, intraoperative findings, procedures, and patient-reported outcomes were recorded, including the 12-Item International Hip Outcome Tool, Non-arthritic Hip Score, Hip Disability and Osteoarthritis Outcome Score, visual analog scale for pain, rates of revision or reoperation, and conversion to total hip arthroplasty. RESULTS: A total of 114 hips (93 patients) for the pincer group were matched 1:1 from 616 hips (541 patients) for the control group. The pincer group (mean ± SD age, 34.5 ± 12.2 years) did not differ in age, body mass index, or follow-up from controls. LCEA was reduced in both groups pre- to postoperatively: the pincer group from 44.0° ± 2.8° to 34.2° ± 3.5° and the controls from 32.9° ± 3.9° to 31.0° ± 3.0°. No differences in improvement were observed: iHOT-12 improved by 35.7 points in both groups (P = .9 for analysis of variance interaction) and Nonarthritic Hip Score by 22.3 points (P = .6). From all eligible surgical procedures, 2-year follow up rates were 2.5% and 2.6% for the pincer and control cohorts, respectively, and 1.2% and 0.3% for conversion to total hip arthroplasty. CONCLUSION: Arthroscopic management of acetabular overcoverage can achieve excellent results, equivalent to arthroscopy for other causes of symptomatic femoroacetabular impingement. A key finding was smaller rim resections producing a mean postoperative LCEA of 34.2° with a small standard deviation.

Arthroscopic, open and mini-open approach for rotator cuff repair: no difference in pain or function at 24 months.

BACKGROUND: The New Zealand Rotator Cuff Registry was established in 2009 to collect prospective functional, pain and outcome data on patients undergoing rotator cuff repair (RCR). METHODS: Information collected included an operation day technical questionnaire completed by the surgeon and Flex Shoulder Function (SF) functional and pain scores preoperatively, immediately post-operatively and at 6, 12 and 24 months. A multivariate analysis was performed analysing the three surgical approaches to determine if there was a difference in pain or functional outcome scores. RESULTS: A total of 2418 RCRs were included in this paper. There were 418 (17.3%) arthroscopic, 956 (39.5%) mini-open and 1044 (43.2%) open procedures. Twenty-four-month follow-up data were obtained for pain and Flex SF in 71% of patients. At 24 months, there was no difference in the average Flex SF score for the arthroscopic, mini-open and open groups. There was no difference in improvement in Flex SF score at 24 months. At 24 months, there was no difference in mean pain scores. There was no difference in improvement in pain score from preoperation to 24 months. Most patients returned to work within 3 months of surgery, with no difference between the three surgical approaches. CONCLUSION: RCR has good to excellent outcomes in terms of improvement in pain and function at 2-year follow-up. We found no difference in pain or functional outcome at 24 months between arthroscopic, open and mini-open approaches for RCR.

MRI Evaluation of Repaired Versus Unrepaired Interportal Capsulotomy in Simultaneous Bilateral Hip Arthroscopy: A Double-Blind, Randomized Controlled Trial.

BACKGROUND: Techniques used in hip arthroscopy continue to evolve, and controversy surrounds the need for capsular repair following this surgical intervention. The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearance of the hip capsule in patients with femoroacetabular impingement (FAI) who underwent simultaneous bilateral hip arthroscopy through an interportal capsulotomy with each hip randomized to undergo capsular repair or not undergo such a repair. METHODS: This double-blind, randomized controlled trial included 15 patients (30 hips), with a mean age of 29.2 years, who underwent simultaneous bilateral hip arthroscopy utilizing a small (<3-cm) interportal capsulotomy for the treatment of FAI. The first hip treated in each patient was intraoperatively randomized to undergo capsular repair or no capsular repair. The contralateral hip then received the opposite treatment. MRI was performed at 6 and 24 weeks postoperatively, and the scans were analyzed by 2 musculoskeletal radiologists. The patients and the radiologists were blinded to the treatment performed on each hip. Capsular dimensions were measured at the level of the healing capsulotomy site and, for hips with a persistent defect, at locations both proximal and distal to the defect. These values were then analyzed at both time points to assess the rate and extent of capsular healing. RESULTS: At 6 weeks postoperatively, a continuous hip capsule (with no apparent capsulotomy defect) was observed in 8 hips treated with capsular repair and 3 hips without such a repair. Of the 19 hips with a discontinuous capsule at 6 weeks, 17 were available for follow-up at 24 weeks postoperatively; all 17 demonstrated progression to healing, with a contiguous appearance without defects and no difference in capsular dimensions between treatment cohorts. CONCLUSIONS: Arthroscopic repair of a small interportal hip capsulotomy site yields an insignificant increase in the percentage of continuous hip capsules seen on MRI at 6 weeks postoperatively compared with no repair. Repaired and unrepaired capsulotomy sites progressed to healing with a contiguous appearance on MRI by 24 weeks postoperatively. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.