A Novel MRI Mapping Technique for Evaluating Bone Bruising Patterns Associated With Noncontact ACL Ruptures.

Background: Bone bruise patterns in the knee can aid in understanding the mechanism of injury in anterior cruciate ligament (ACL) ruptures. There is no universally accepted magnetic resonance imaging (MRI) mapping technique to describe the specific locations of bone bruises. Hypothesis: The authors hypothesized that (1) our novel mapping technique would show high interrater and intrarater reliability for the location of bone bruises in noncontact ACL-injured knees and (2) the bone bruise patterns reported from this technique would support the most common mechanisms of noncontact ACL injury, including valgus stress, anterior tibial translation, and internal tibial rotation. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included were 43 patients who underwent ACL reconstruction between 2018 and 2020, with MRI within 30 days of the injury on a 3.0-T scanner, documentation of a noncontact mechanism of injury, and no concomitant or previous knee injuries. Images were retrospectively reviewed by 2 radiologists blinded to all clinical data. The locations of bone bruises were mapped on fat-suppressed T2-weighted coronal and sagittal images using a novel technique that combined the International Cartilage Repair Society (ICRS) tibiofemoral articular cartilage surgical lesions diagram and the Whole-Organ Magnetic Resonance Imaging Scoring (WORMS) mapping system. Reliability between the reviewers was assessed using the intraclass correlation coefficient (ICC), where ICC >0.90 indicated excellent agreement. Results: The interrater and intrarater ICCs were 0.918 and 0.974, respectively, for femoral edema mapping and 0.979 and 0.978, respectively, for tibial edema mapping. Significantly more bone bruises were seen within the lateral femoral condyle compared with the medial femoral condyle (67% vs 33%; P < .0001), and more bruises were seen within the lateral tibial plateau compared with the medial tibial plateau (65% vs 35%; P < .0001). Femoral bruises were almost exclusively located in the anterior/central regions (98%) of the condyles as opposed to the posterior region (2%; P < .0001). Tibial bruises were localized to the posterior region (78%) of both plateaus as opposed to the anterior/central regions (22%; P < .0001). Conclusion: The combined mapping technique offered a standardized and reliable method for reporting bone bruises in noncontact ACL injuries. The contusion patterns identified using this technique were indicative of the most commonly reported mechanisms for noncontact ACL injuries.

Examining the Bone Bruise Patterns in Multiligament Knee Injuries With Peroneal Nerve Injury.

BACKGROUND: Tibiofemoral bone bruise patterns seen on magnetic resonance imaging (MRI) are associated with ligamentous injuries in the acutely injured knee. Bone bruise patterns in multiligament knee injuries (MLKIs) and particularly their association with common peroneal nerve (CPN) injuries are not well described. PURPOSE: To analyze the tibiofemoral bone bruise patterns in MLKIs with and without peroneal nerve injury. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We retrospectively identified 123 patients treated for an acute MLKI at a level 1 trauma center between January 2001 and March 2021. Patients were grouped into injury subtypes using the Schenck classification. Within this cohort, patients with clinically documented complete (motor and sensory loss) and/or partial CPN palsies on physical examination were identified. Imaging criteria required an MRI scan on a 1.5 or 3 Tesla scanner within 30 days of the initial MLKI. Images were retrospectively interpreted for bone bruising patterns by 2 board-certified musculoskeletal radiologists. The location of the bone bruises was mapped on fat-suppressed T2-weighted coronal and sagittal images. Bruise patterns were compared among patients with and without CPN injury. RESULTS: Of the 108 patients with a MLKI who met the a priori inclusion criteria, 26 (24.1%) were found to have a CPN injury (N = 20 complete; N = 6 partial) on physical examination. For CPN-injured patients, the most common mechanism of injury was high-energy trauma (N = 19 [73%]). The presence of a grade 3 posterolateral corner (PLC) injury (N = 25; odds ratio [OR], 23.81 [95% CI, 3.08-184.1]; P = .0024), anteromedial femoral condyle bone bruising (N = 24; OR, 21.9 [95% CI, 3.40-202.9]; P < .001), or a documented knee dislocation (N = 16; OR, 3.45 [95% CI, 1.38-8.62]; P = .007) was significantly associated with the presence of a CPN injury. Of the 26 patients with CPN injury, 24 (92.3%) had at least 1 anteromedial femoral condyle bone bruise. All 20 (100%) patients with complete CPN injury also had at least 1 anteromedial femoral condyle bone bruise on MRI. In our MLKI cohort, the presence of anteromedial femoral condyle bone bruising had a sensitivity of 92.3% and a specificity of 64.6% for the presence of CPN injury on physical examination. CONCLUSION: In our MLKI cohort, the presence of a grade 3 PLC injury had the greatest association with CPN injury. Additionally, anteromedial femoral condyle bone bruising on MRI was a highly sensitive finding that was significantly correlated with CPN injury on physical examination. The high prevalence of grade 3 PLC injuries and anteromedial tibiofemoral bone bruising suggests that these MLKIs with CPN injuries most commonly occurred from a hyperextension-varus mechanism caused by a high-energy blow to the anteromedial knee.

Injury to the Meniscofemoral Portion of the Deep MCL Is Associated with Medial Femoral Condyle Bone Marrow Edema in ACL Ruptures.

BACKGROUND: The primary goal of the present study was to investigate injury to the deep medial collateral ligament (MCL), specifically the meniscofemoral ligament (MFL) portion, and its association with medial femoral condyle (MFC) bone marrow edema in acute anterior cruciate ligament (ACL) ruptures. The secondary goal was to examine the association between MFL injury and medial meniscal tears (MMTs) in these same patients. METHODS: Preoperative magnetic resonance imaging (MRI) scans of 55 patients who underwent ACL reconstruction surgery were retrospectively reviewed by 2 board-certified musculoskeletal radiologists. MRI scans were examined for MFC edema at the insertion site of the MFL. This site on the MFC was referred to as the central-femoral-medial-medial (C-FMM) zone based on the coronal and sagittal locations on MRI. The presence or absence of bone marrow edema within this zone was noted. The prevalence, grade, and location of superficial MCL and MFL injuries were also recorded on MRI. The correlations between MFL injuries and the presence of MFC bone marrow edema were examined. Lastly, the presence and location of MMTs were also recorded on MRI and were confirmed on arthroscopy, according to the operative notes. RESULTS: On MRI, 40 (73%) of the 55 patients had MFL injuries. MFL injuries were significantly more common than superficial MCL injuries (p = 0.0001). Of the 27 patients with C-FMM bruising, 93% (25 patients) had MFL tears (p < 0.00001). In addition, of the 40 patients with an MFL injury, 63% (25 patients) had C-FMM bruising (p = 0.0251). Chi-square testing showed that MMTs and MFL injuries were significantly associated, with 12 (100%) of 12 patients with MMTs also having a concomitant MFL injury (p = 0.0164). CONCLUSIONS: The prevalence of MFL injury in ACL ruptures is high and MFC bone marrow edema at the MFL insertion site should raise suspicion of injury. MFL injuries can present with clinically normal medial ligamentous laxity in ACL ruptures. Additionally, MFL injuries were significantly associated with posterior horn MMTs, which have been shown in the literature to be a potential risk factor for ACL graft failure. CLINICAL RELEVANCE: As deep MCL injuries are difficult to detect on physical examination, our findings suggest that the reported MFC edema in ACL ruptures can act as an indirect sign of MFL injury and may aid in the clinical detection. Additionally, due to the anatomical connection of the deep MCL and the meniscocapsular junction of the posterior horn of the medial meniscus, if an MFL injury is suspected through indirect MFC edema at the insertion site, the posterior horn of the medial meniscus should also be assessed for injury, as there is an association between the 2 injuries in ACL ruptures.

Isolated avulsion fracture at the medial head of the gastrocnemius muscle.

An isolated avulsion fracture involving the femoral origin of the medial head of the gastrocnemius muscle without an associated muscular, meniscal, or ligamentous injury is extremely rare. We report a case of a 14-year-old male wrestler who presented with a radiographically occult avulsion fracture of the medial gastrocnemius tendon sustained during competition. To our knowledge, this is the first case to describe a mechanism of injury as well as to report a return to competition after non-operative management.

Sex differences in factors influencing recovery from arthroscopic knee surgery.

BACKGROUND: Many factors affect recovery from arthroscopic partial meniscectomy, including patient sex. However, sex differences in time to maximal recovery of knee function and factors influencing differential rates of recovery are unknown. QUESTIONS/PURPOSES: We determined (1) preoperative sex differences, (2) sex differences in rate and extent of recovery through 1 year postoperatively, and (3) clinical and fitness variables that could explain potential sex differences in recovery from partial meniscectomy. PATIENTS AND METHODS: The study sample consisted of 180 patients undergoing arthroscopic partial meniscectomy. Sex, age, body mass index, history of prior injury, length of time between knee injury/impairment and surgical evaluation, weekly exercise frequency, and self-reported fitness were assessed preoperatively, and extent of osteoarthritis was recorded postoperatively. We used the Tegner-Lysholm scale to assess knee function preoperatively and postoperatively at weeks 1, 3, 8, 16, 24, and 48 followups. RESULTS: Females had worse knee function and delayed maximal recovery, requiring 1 year, compared with males, who required only 4 months. History of prior knee injury and lower self-reported fitness were associated with slower recovery in females but not in males. Osteoarthritis was associated with slower recovery but not related to sex. Body mass index, length of time between injury/impairment and surgical evaluation, and weekly exercise frequency did not influence rate of recovery. CONCLUSIONS: Females have delayed recovery after arthroscopic partial meniscectomy. Prior knee injury and self-reported low fitness are associated with delayed recovery for females but not for males.

Surgical stress-induced immune cell redistribution profiles predict short-term and long-term postsurgical recovery. A prospective study.

BACKGROUND: The experience of undergoing surgery is known to induce a short-term, fight-or-flight physiological stress response. As an optimum immune response at the site of surgery would enhance tissue repair, we examined surgical stress-induced immune cell redistribution profiles as predictors, and potential mediators, of short and long-term postoperative recovery. We tested the a priori hypothesis that predefined adaptive immune cell redistribution profiles observed during surgery will predict enhanced postoperative recovery. METHODS: This prospective longitudinal study involved fifty-seven patients undergoing meniscectomy. Knee function was assessed preoperatively and at one, three, eight, sixteen, twenty-four, and forty-eight weeks postoperatively with use of the clinically validated Lysholm scale, which assesses mechanical function, pain, mobility, and the ability to perform daily activities. Surgery-induced immune cell redistribution was measured in the blood at baseline, before surgery, and after surgery. RESULTS: Mixed-model repeated-measures analyses revealed a main effect of immune cell redistribution: patients who showed the predefined "adaptive" lymphocyte and monocyte redistribution profiles during surgery showed enhanced recovery. Interesting differences were also observed between the sexes: women as a group showed less adaptive redistribution and correspondingly showed significantly delayed maximum recovery, requiring forty-eight weeks, compared with men, who required only sixteen weeks. Inter-individual differences in leukocyte redistribution predicted the rate of recovery across both sexes. CONCLUSIONS: Immune cell redistribution that is induced by the stress of undergoing surgery can predict (and may partially mediate) postoperative healing and recovery. These findings may provide the basis for identifying patients (either prospectively or during surgery) who are likely to show good as opposed to poor recovery following surgery and for designing interventions that would maximize protective immune responses and enhance the rate and extent of recovery.

Mood and attitude predict pain outcomes following arthroscopic knee surgery.

BACKGROUND: Decreased pain represents a clinically important outcome following arthroscopic knee surgery. However, little is known about preoperative mood and attitudinal factors and their potential relationship with pain outcomes. PURPOSE: This prospective, longitudinal study investigated the influence of preoperative depression, stress, and optimism on pain severity and interference with functioning, controlling for relevant demographic and clinical factors 1 year postoperatively. METHODS: Participants (N = 180, mean age = 48.2 years) completed scales assessing pain severity and interference both preoperatively and postoperatively. Demographics, depression, stress, optimism, and body mass index were assessed preoperatively. Physicians assessed extent of knee osteoarthritis during surgery. RESULTS: Hierarchical regression analyses controlling for relevant demographic and clinical variables revealed that optimism and stress were significant predictors of pain severity at 1 year but not pain interference. Extent of osteoarthritis predicted pain interference. CONCLUSIONS: These findings support that optimism and stress are important predictors of patient-rated pain severity. They do not, however, predict the extent to which pain interferes with daily functioning.

Predictors of short-term recovery differ from those of long-term outcome after arthroscopic partial meniscectomy.

PURPOSE: The purpose of this study was to determine which patient clinical and demographic factors are associated with the short-term rate of recovery from arthroscopic partial meniscectomy in the year after surgery and how they differ from previously published associations with long-term outcome. METHODS: Depth of meniscal excision, involvement of 1 or both menisci, extent of meniscal tear, and extent of osteoarthritis were determined during surgery, and age, body mass index, and gender were recorded. Mixed-model repeated-measures analyses were used longitudinally to identify independent predictors of recovery, measured by prospectively assessing knee pain, knee function, and overall physical knee status preoperatively and at regular intervals throughout postoperative recovery. RESULTS: Neither advanced age nor increased body mass index had any influence on patient recovery over time, whereas gender was implicated, with women having significantly poorer recovery scores than men (P < .04). In addition, differences in variables indicating extent of meniscal tear and resection did not influence recovery scores over time, and the only surgical factor that impacted all 3 recovery variables was extent of osteoarthritis (P < .02). CONCLUSIONS: We have shown that female gender and worse osteoarthritis are associated with a slower rate of short-term recovery from arthroscopic partial meniscectomy whereas age, obesity, and amount of meniscal tear/resection showed no association with rate of recovery throughout the first year postoperatively. LEVEL OF EVIDENCE: Level I, high-quality prognostic prospective study (all patients were enrolled at the same point in their disease with more than 80% follow-up of enrolled patients).

Surgical outcomes after arthroscopic partial meniscectomy.

Much research has been done to determine clinical and demographic variables associated with outcomes from arthroscopic partial meniscectomy for meniscal tears. We undertook a review of the literature to determine trends regarding outcomes from this procedure. Independent variables were analyzed for associations with outcome, and outcome measures and methods of statistical analysis were reviewed. Results of these studies demonstrate that patient age and sex had no significant association with any clinical or radiographic outcome variables at 8.5, 12, and 15 years. Patients with flap tears had slower return to sports and more revisions than did those with bucket handle tears. Osteoarthritis progressed more after medial partial meniscectomy in patients older than age 40 years than in younger patients. No statistically significant difference in medial versus lateral meniscectomy overall was shown. The best radiographic results in patients who underwent medial meniscectomy occurred in valgus knees compared with varus knees. Increased Modified Outerbridge cartilage scores at the time of surgery correlated with poorer physical results at 12 years.

Hip arthroscopy without a perineal post: a safer technique for hip distraction.

Pudendal nerve palsy is a reported complication of hip arthroscopy. We report a technique using a deflated taped beanbag rather than a perineal post. The patient is placed in the supine or lateral position on a fracture table. The beanbag is contoured around the patient's flank and thorax. The distal aspect of the beanbag is placed no further than the iliac crest, and care is taken to avoid compression of the posterior aspect of the axillary region or the posterior humerus. The molded beanbag is deflated, a blanket is positioned over the abdomen and lower thorax, and with the use of 3-in-wide cloth tape, the patient and beanbag are secured to the operative table circumferentially. The superior margin of the deflated beanbag remains firm, preventing compression of the thorax and avoiding compromised ventilation. The arm on the operative side is placed across the chest and secured to avoid obstruction of the operative field. This patient positioning provides sufficient stability for adequate traction and good visualization while minimizing the risk of a pudendal nerve palsy.

Psychosocial factors and surgical outcomes: an evidence-based literature review.

The influence of psychosocial factors on clinical outcomes after surgery has been investigated in several studies. This review is limited to surgical outcomes studies published between 1990 and 2004 that include (1) psychosocial variables (eg, depression, social support) as predictors of outcome and that focus on (2) clinical outcomes (eg, postoperative pain, functional recovery) using (3) specific multivariate analytic techniques with (4) relevant clinical variables (eg, presurgical health status) included as covariates. Twenty-nine studies met these criteria. Results indicate that psychosocial factors play a significant role in recovery and are predictive of surgical outcome, even after accounting for known clinical factors. Attitudinal and mood factors were strongly predictive; personality factors were least predictive. The results suggest that preoperative consideration of attitudinal and mood factors will assist the surgeon in estimating both the speed and extent of postoperative recovery.

Implications of the pivot shift in the ACL-deficient knee.

UNLABELLED: The Losee repair controls rotational subluxation of the lateral femoral condyle, or pivot shift, but does not reliably eliminate Lachman laxity. Despite this surgical limitation, many patients who were operated on continued to do high-demand activities at the last followup. We hypothesized that Lachman findings alone did not predict poor surgical outcome or progression to osteoarthritis. We report on 87 patients evaluated at an average of 9 years (range, 5-21 years) postoperatively. Prospectively collected examinations and radiographic, subjective, and objective outcome measures were recorded and statistically evaluated. The presence of a postoperative pivot shift or residual varus laxity correlated with poor patient subjective evaluations and poor scoring outcomes. Lachman laxity with an absent pivot shift had no correlation with the outcome measures or onset of radiographic progression to osteoarthritis. Meniscectomy, additional knee surgery, increased valgus or varus laxity, and time from injury until the final radiograph positively correlated with the onset of osteoarthritis. Elimination of the pivot shift was necessary to achieve successful relief of symptoms and functional outcome. In the absence of a pivot shift, Lachman laxity was not solely predictive of poor outcomes. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Shared decision making, preoperative expectations, and postoperative reality: differences in physician and patient predictions and ratings of knee surgery outcomes.

PURPOSE: The present study was performed to determine the extent to which physicians and patients rate preoperative and postoperative knee pain and function differently, and to determine whether physicians or patients more accurately predict postoperative knee pain and function. TYPE OF STUDY: Longitudinal, prospective study. METHODS: Ninety-eight patients requiring either anterior cruciate ligament reconstruction surgery or meniscectomy and related surgery were interviewed 1 week before surgery, as well as 3 and 24 weeks postoperatively. Patients and their physicians completed ratings on knee pain and function at each time point. In addition, at their preoperative visit, patients and physicians completed ratings predicting their postoperative pain and functional status. RESULTS: Physicians rated patients as having less pain and greater knee function preoperatively and at 24 weeks postoperatively. Patients had more significant differences between predicted and actual ratings. CONCLUSIONS: Physicians tended to underestimate knee pain and overestimate knee function compared with patients. However, physicians better predicted postoperative knee pain and function ratings than did patients. These findings suggest that physician-patient discussions about preoperative expectations and postoperative reality might be an important part of clinical care. LEVEL OF EVIDENCE: Level II, Prospective Longitudinal Study.

MR arthrography of anterior cruciate ligament reconstruction grafts.

OBJECTIVE: Our objective was to determine the accuracy of MR arthrography for identification of tears of anterior cruciate ligament reconstruction grafts and for detection of localized anterior arthrofibrosis and impingement. MATERIALS AND METHODS: We retrospectively identified 27 patients (mean age, 31 years; range, 18-45 years) with anterior cruciate ligament reconstruction who had undergone MR arthrography followed by arthroscopy within 1 year. Three radiologists independently reviewed the MR arthrograms for the presence or absence of graft tear, localized anterior arthrofibrosis, and impingement. RESULTS: Graft tears were identified with 100% sensitivity by all three reviewers with specificities of 100%, 89%, and 94%. Localized anterior arthrofibrosis was identified with 100% sensitivity by all reviewers, with specificities of 79%, 71%, and 38%. Impingement was detected with sensitivities and specificities of 83% and 100%, 83% and 52%, and 33% and 90% by the three reviewers, respectively. Interobserver agreement was almost perfect for detection of graft tear (kappa = 0.83, 0.92, and 0.83), was fair to moderate for detection of localized anterior arthrofibrosis (kappa = 0.50, 0.32, and 0.22), and was slight to fair for detection of impingement (kappa = 0.40, 0.08, and 0.35). CONCLUSION: MR arthrography can accurately depict the presence of anterior cruciate ligament graft tears. Localized anterior arthrofibrosis and graft impingement were less accurately detected and showed greater observer variability.

Technical tips in orthopaedics: meniscal repair with use of an in situ fibrin clot.

The importance of meniscal preservation has become increasingly clear, and many authors advocate repair of the meniscus whenever possible, forgoing patient age and tear location. In accordance with the common goal of preserving meniscal tissue, we describe a simple technique to augment meniscal repairs with the use of an in situ fibrin clot. The site is prepared accordingly: the synovium directly above the tear site is abraded with a shaver, rasp, or small intra-articular banana blade. Next, the water inflow cannula is closed, and the outflow cannula is opened to vacuum suctioning, allowing collapse of the distended joint. Under these circumstances, negative intra-articular pressure is produced in the knee joint. This condition is maintained for a period of 1 to 2 minutes and induces bleeding from the abraded synovial site. The knee in a dependent position causes the blood to run down the synovial wall and into the meniscal cleft, pooling there and forming a clot adherent to the edges of the separated meniscal tear. This procedure has been found to be a simple and minimally invasive mechanism for clot placement. The exposed collagen of the meniscal tear provides an ideal surface for a relatively tenacious clot attachment. It provides the healing factors reported to induce successful meniscal healing.

Vascular leiomyoma presenting as medial joint line pain of the knee.

We present the case of a 27-year-old woman with a subcutaneous vascular leiomyoma occurring around the knee. The patient presented with a several-year history of medial-sided knee pain with an unknown etiology. The clinical presentation, magnetic resonance imaging, and histopathologic features are reported, and the literature pertaining to the clinicopathologic characteristics is reviewed. By including vascular leiomyomas in the differential of painful lower extremity subcutaneous masses, an early accurate diagnosis is possible.

Muscle contusion injury and myositis ossificans traumatica.

In athletic competition, muscle contusion injury is a frequent and debilitating condition. Found in traditional contact and noncontact sports, contusions also can occur to the nonathlete by simple falls and accidents. The injury consists of a well-defined sequence of events involving microscopic rupture and damage to muscle cells, macroscopic defects in muscle bellies, infiltrative bleeding, and inflammation. The repair of the tissue can be thought of as a race between remodeling and scar formation. In the current study, the authors describe the relevant body of research directed at delineating the incidence, factors that affect injury severity, and treatment of muscle contusion injury. Emphasis is given to animal models that allow reproducible, quantitative injury, and study of the effects of various treatment modalities. Myositis ossificans traumatica, one of the most debilitating consequences of contusion injuries, also is discussed. The incidence, causative factors, and prevention strategies are reviewed.

Grade 2C signal in the meniscus [correction of mensicus] on MR imaging of the knee.

OBJECTIVE: The objective of our study was to evaluate the clinical significance of grade 2C meniscal [corrected] signal (an extensive triangular or wedge-shaped signal that does not reach the surface on more than one image) on MR imaging of the knee. MATERIALS AND METHODS: Review of 1106 MR imaging reports over 2 years revealed 88 patients with menisci described as containing triangular, wedge-shaped, extensive, or grade 2C signal. Image review by consensus of two radiologists found 34 menisci in 29 patients that fit criteria for grade 2C signal. Seven menisci containing grade 2C signal were evaluated with arthroscopy. An additional three patients with grade 2C meniscal signal with arthroscopic correlation were identified from 4 previous years. RESULTS: Prevalence of grade 2C signal was 1.5% (34/2212 menisci). Seven (21%) of these 34 menisci had subsequent arthroscopy and three of these had meniscal tears. Including the three additional menisci with grade 2C signal from 4 previous years, five (50%) of 10 menisci with grade 2C signal were torn at arthroscopy. No difference was noted between torn and intact menisci in the number of images with grade 2C signal. In patients with tears, the range was three to 10 images (mean, 6.6 images) compared with a range of two to 10 images (mean, 6.6 images) in patients without tears. The maximal percentage of area of abnormal signal in patients with tears ranged from 70% to 90% (mean, 80%) compared with a range of 60-90% (mean, 82%) in patients without tears. The patient age range was 23-64 years (mean, 47 years) in patients with tears and 16-67 years (mean, 47 years) in patients without tears. CONCLUSION: Grade 2C meniscal signal has a low incidence. Although half of patients with symptoms meriting arthroscopy have tears, most patients with grade 2C signal are not treated with arthroscopy.

Effect of aging on male and female master athletes' performance in strength versus endurance activities.

Aging has traditionally been associated with several functional declines within the musculoskeletal system. In this study, we characterized and compared age-related changes in performance in power and endurance activities (ie, power-lifting, stationary rowing). From age 25 to age 85, men's and women's rowing performance decreases 29%; from age 25 to age 55, men's rowing performance decreases 0.12% per year, and women's performance decreases 0.23% per year. The pattern of decline in power-lifting performance is characterized by earlier onset and more rapid progression. During the fourth decade, men's and women's power-lifting performance decreases 3% per year; thereafter, their performance decreases 1% per year. The difference between the age-related change rates for rowing and power-lifting is statistically significant (P = .05). The older athletes' performance in both activities suggests that the capacity for significant function in activities requiring power and endurance persists throughout life in individuals who train and who remain in good health. That strength decreases more rapidly than endurance capacity points to the importance of resistance exercises for minimizing muscle weakness in an aging population.