Current state of unloading braces for knee osteoarthritis.

PURPOSE: Unicompartmental knee osteoarthritis (OA) is often treated with the prescription of an unloading knee brace to decrease pain and stiffness. Braces have been shown to improve the quality of life by applying an external moment to offset increased compressive tibiofemoral contact loads, but evidence regarding mechanical efficacy at the joint is controversial. Thus, the purpose of this study was to review the current state of unloading braces on knee mechanics, clinical impact, and long-term disease progression. METHODS: A literature search was performed through the PubMed MEDLINE database for the search terms "osteoarthritis," "knee," "brace," and derivatives of the keyword "unload." Articles published since January 1, 1980 were reviewed for their relevance. Evidence for the effectiveness of unloading braces for disease management both biomechanically and clinically was considered. RESULTS: While significant research has been done to show improvement in OA symptoms with the use of an unloading brace, current literature suggests a debate regarding the effectiveness of these braces for biomechanical change. Clinical findings reveal overall improvements in parameters such as pain, instability, and quality of life. CONCLUSION: Although clinical evidence supports brace use to improve pain and functional ability, current biomechanical evidence suggests that unloading of the affected knee compartment does not significantly hinder disease progression. LEVEL OF EVIDENCE: III.

Meniscus suture repair: minimum 10-year outcomes in patients younger than 40 years compared with patients 40 and older.

BACKGROUND: Few studies have compared outcomes after meniscus suture repair in patients younger than 40 years versus patients 40 years and older. PURPOSE: To document failure rates and long-term outcomes after meniscus suture repair by a single surgeon, using the inside-out technique, at a minimum 10-year follow-up in patients younger than 40 years versus those 40 years and older. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This study included all patients 18 years or older who underwent meniscus suture repair with the inside-out technique by a single surgeon between January 1992 and December 2003. Patients were divided into 2 cohorts according to age: <40 years (cohort 1) and ≥40 years (cohort 2). If patients underwent subsequent knee surgery, all subsequent reports, whether performed by the original treating surgeon or by a different surgeon elsewhere, were reviewed by 2 independent reviewers not involved in the primary care of the patients. Reviewers classified surgeries as failures if the subsequent surgery treated the same area of the meniscus as repaired in the index surgery. Patients completed a subjective questionnaire at minimum of 10 years after arthroscopy. Outcomes measures included Lysholm, Tegner, and patient satisfaction with outcome. All data were collected prospectively. RESULTS: The surgeon performed 339 meniscus repairs between 1992 and 2003. The study included 181 knees in 178 patients, who had a mean age of 33 years (range, 18-70 years). Cohort 1 contained 136 knees; 16 patients (12%) were lost to follow-up and 47 (35%) underwent a subsequent knee arthroscopy. Cohort 2 contained 45 knees; 2 patients (4.4%) were lost to follow-up, 3 patients had a total knee arthroplasty, and 12 patients (28%) underwent a subsequent knee arthroscopy. In cohort 1, the meniscus repair failure rate was 5.5% (6/110), and in cohort 2 it was 5.3% (2/38) (P = .927). There was no significant difference in failure rate based on which meniscus was repaired (P = .257), concomitant anterior cruciate ligament (ACL) reconstruction (P = .092), or microfracture (P = .674). Average follow-up time for cohort 1 was 16.1 years (range, 10.0-21.9 years), with 82% follow-up (n = 73/89); average follow-up time for cohort 2 was 16.2 years (range, 10.1-21.0 years), with 93% follow-up (n = 28/30). There were no significant differences in outcomes scores after meniscus suture repair based on age cohort or meniscus side, presence of an ACL tear, or concomitant microfracture procedure. CONCLUSION: Meniscus repair failure rate was not different in patients who were younger than 40 years versus those who were 40 years or older at time of meniscus index surgery. Patients who underwent meniscus suture repair had high function and high patient satisfaction at an average of 16 years after meniscus suture repair, and no differences were seen based on age.

Posterior meniscus root tears: associated pathologies to assist as diagnostic tools.

PURPOSE: The purpose of this study was to investigate associated pathologies identified at arthroscopy in patients with meniscus root tears. METHODS: This study was Institutional Review Board approved. All patients who underwent arthroscopic knee surgery where a complete meniscus root tear was identified were included in this study. Concurrent ligament tears and articular cartilage changes ≥Outerbridge grade 2 were recorded and stored in a data registry. RESULTS: Fifty patients (28 males, 22 females) [mean age = 36.5 years (range 17.1-68.1 years)] who were diagnosed with a medial or lateral meniscus root tear at arthroscopy were included in this study out of 673 arthroscopic surgeries (prevalence 7.4 %). Twenty-three (46 %) patients had a medial meniscus root tear, 26 (52 %) patients had a lateral meniscus root tear and one (2 %) patient had both. Thirty-four per cent of patients (n = 17) underwent partial meniscectomy, while 60 % (n = 31) underwent suture repair. During arthroscopy, 60 % (n = 30) of patients were diagnosed with an anterior cruciate ligament (ACL) tear. Patients with lateral meniscus root tears were 10.3 times (95 % CI 2.6-42.5) more likely to have ACL tears than patients with medial meniscus root tears (p = 0.012). Patients who had medial meniscus root tears were 5.8 times (95 % CI 1.6-20.5) more likely to have chondral defects than patients who had lateral meniscus root tears (p = 0.044). CONCLUSION: In this study, patients' preoperative functional scores and activity levels were low. Patients with lateral meniscal root tears were more likely to have an ACL tear. Patients with medial meniscal root tears were more likely to have an knee articular cartilage defect with an Outerbridge grade 2 or higher chondral defect. This study confirms the importance of comprehensive assessment of concurrent injuries to properly diagnose meniscus root tears. LEVEL OF EVIDENCE: IV.

Outcomes following microfracture of full-thickness articular cartilage lesions of the knee in adolescent patients.

The purpose of this study was to document outcomes following microfracture for full-thickness cartilage defects of the knee in adolescents. Our hypothesis was that patients aged 18 years or less would have excellent outcomes and function following microfracture of full-thickness knee articular cartilage defects. This study was approved by the Institutional Review Board. Patients < 19 years old with full-thickness knee articular cartilage defects treated with microfracture between January 1992 and June 2008 were identified. Surgical, demographic data, Lysholm score, Tegner activity scale, and patient satisfaction were collected prospectively. A total of 26 patients (14 females, 12 males) met inclusion criteria. Average age was 16.6 years (range: 12-18.9 years). Ninety-six percent of lesions were patellar (37%) or femoral condyle defects (medial 26%, lateral 33%). Minimum 2-year follow-up was obtained in 22/26 patients (85%) with average follow-up of 5.8 years (range: 2.0-13.3 years). Average postoperative Lysholm score was 90 (range: 50-100). Median Tegner scale was 6 (range: 2-10). Median patient satisfaction with outcome was 10 (range: 1-10). Lysholm correlated with Tegner scale (rho = 0.586; p = 0.011) and patient satisfaction (rho = 0.70; p = 0.001). Average postoperative Lysholm score in males was 93 and 86 in females (p = 0.22). One patient underwent revision microfracture. This study showed that adolescent patients who underwent microfracture for treatment of full-thickness knee chondral defects demonstrated increased activity levels and excellent function following surgery.

Outcomes after knee microfracture of chondral defects in alpine ski racers.

Articular cartilage defects of the knee have been shown to cause pain, swelling, decreased function, and suboptimal athletic performance. Treatment of elite-level athletes presenting with full-thickness chondral defects of the knee continues to be a challenge for orthopedic surgeons. The purpose of this study was to document outcomes in elite professional alpine ski racers after microfracture surgery. This study was approved by an institutional review board. All patients who competed in professional ski races recognized by International Ski Federation and had a full-thickness knee articular cartilage defect, treated with microfracture, by a single surgeon, were included in the study. All data were collected prospectively. At minimum 2 years following microfracture, all patients completed a questionnaire, including Lysholm score, Tegner activity scale, and patient satisfaction with outcome. Minimum 2-year follow-up was available for 18 of 20 skiers (90%) at an average follow-up of 77 months (range, 24-255 months). Size of knee articular cartilage defect was larger in males (195 mm(2)) compared with females (155 mm(2)); however, this difference was not statistically significant (p > 0.05). Median postoperative Tegner activity scale was 10 (range, 4-10). Mean postoperative Lysholm score was 86 (range, 41-100). Median postoperative patient satisfaction score was 10 (range, 9-10). Out of the 20 skiers, 19 (95%) returned to competitive skiing. The age of the skier who did not return was 28 years. The average time from surgery to return to competition was 13.4 months (range, 0.5-25.3 months). Average end-of-season overall World Cup ranking was calculated for the nine skiers before and after surgery. Of these nine skiers, six had an improved average overall World Cup ranking after microfracture. In this study, patient satisfaction with outcome and function were high following microfracture of full-thickness chondral lesions of the knee. Nearly all skiers returned to full competition. Microfracture is an acceptable treatment option for elite skiers who have full thickness articular cartilage lesions of the knee.

Ten-year survivorship after knee arthroscopy in patients with Kellgren-Lawrence grade 3 and grade 4 osteoarthritis of the knee.

PURPOSE: The purpose of this study was to document 10-year outcomes and total knee arthroplasty (TKA) rate after arthroscopic treatment of knee osteoarthritis and compare survivorship of patients with Kellgren-Lawrence (KL) grade 3 and 4 knees. METHODS: Eighty-one knees in 73 patients (49 male, 32 female; mean age, 58 years; range, 37 to 79 years) that underwent an arthroscopic regimen for knee osteoarthritis between August 2000 and November 2001 were included in this institutional review board-approved study. The inclusion criterion was Kellgren-Lawrence (KL) grade 3 or 4 radiographic changes. A TKA had been recommended to all patients; however, none wished to undergo arthroplasty. All patients underwent arthroscopic treatment. Endpoint was defined as TKA for survivorship analysis. Outcomes were collected at a minimum follow-up of 10 years (Lysholm, Tegner, patient satisfaction, and WOMAC scores). RESULTS: Of 81 knees, 7 were in patients who died and 2 in patients who refused to participate, leaving 72 knees available for follow-up. Follow-up was obtained for 95% of patients (n = 69). Forty-three knees (62%) were converted to TKA at a mean of 4.4 years (range 1.0 to 9.6) after index arthroscopy. Mean survival time was 6.8 years (95% confidence interval [CI], 5.9 to 7.6 years). Survivorship was 60% at 5 years and 40% at 10 years. Patients with KL grade 4 osteoarthritis were 5.3 times more likely to fail (95% CI, 1.3 to 23.4) than those with KL grade 3 (P = .012). Mean survival time for patients with KL grade 4 was 5.7 years (95% CI, 4.5 to 6.9), and mean survival time for those with KL grade 3 was 7.5 years (95% CI, 6.2 to 8.7) (P = .022). For 26 knees that did not undergo arthroplasty, the mean Lysholm score was 74 (95% CI, 67 to 80), the median Tegner activity scale score was 3 (range, 0 to 8), the median patient satisfaction with outcome was 9 (range, 1 to 10), and the mean WOMAC score was 18.5 (95% CI, 13 to 24) at 10 years of follow-up. CONCLUSIONS: The mean survival time after arthroscopic treatment of osteoarthritis with a defined protocol was 6.8 years. Forty percent delayed arthroplasty for a minimum of 10 years. Patients with KL grade 4 changes in their knee had a higher risk of conversion to arthroplasty and a significantly lower mean survival time. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

High knee valgus in female subjects does not yield higher knee translations during drop landings: a biplane fluoroscopic study.

The goal of this study was to determine the effects of peak knee valgus angle and peak knee abductor moment on the anterior, medial, and lateral tibial translations (ATT, MTT, LTT) in the "at risk" female knee during drop landing. Fifteen female subjects performed drop landings from 40 cm. Three-dimension knee motion was simultaneously recorded using a high speed, biplane fluoroscopy system, and a video-based motion analysis system. Valgus knee angles and knee abduction moments were stratified into low, intermediate, and high groups and peak ATT, MTT, and LTT were compared between these groups with ANOVA (α = 0.05). Significant differences were observed between stratified groups in peak knee valgus angle (p < 0.0001) and peak knee abduction moment (p < 0.0001). However, no corresponding differences in peak ATT, LTT, and MTT between groups exhibiting low to high-peak knee valgus angles (ATT: p = 0.80; LTT: p = 0.25; MTT: p = 0.72); or, in peak ATT (p = 0.61), LTT (p = 0.26) and MTT (p = 0.96) translations when stratified according to low to high knee abduction moments, were found. We conclude that the healthy female knee is tightly regulated with regard to translations even when motion analysis derived knee valgus angles and abduction moments are high.

Improvement in quality of life with use of an unloader knee brace in active patients with OA: a prospective cohort study.

The purpose of this study was to determine if short form (SF)-12 physical component would increase with unloader brace use. Patient expectations and predictors of significant improvement were determined. Our hypothesis was that patients with unloader braces will have increases in general physical health (SF-12) and function (Western Ontario and McMaster Universities Arthritis Index [WOMAC]). Patients were enrolled in institutional review board-approved prospective cohort study. They completed a self-administered questionnaire (SF-12; WOMAC, Tegner activity scale, expectations) at enrollment, 3 weeks, 6 weeks, and 6 months. In this study, 39 patients, 23 males and 16 females (average age = 61 years [range 44 to 87]), were prescribed an unloader brace. Patients had significant improvement in quality of life (SF-12) (p < 0.05). There was significant improvement in pain, stiffness, and function (WOMAC) (p < 0.05). Patients who reported Tegner of 3 or greater at final follow-up had significantly higher SF-12 physical component (48 vs. 37; p = 0.023). Return to recreational sports was very important in 83% and somewhat important in 17%. Improving ability to walk was very important in 89%. Pain relief was very important in 69%, somewhat important in 17%. Of these, 39% expected most pain to be relieved and 57% expected all pain to be relieved. The most important expectations were to have confidence in knee (97% very important), avoid future knee degeneration (90% very important), and improve ability to maintain general health (93% very important). Patients demonstrated a significant decrease in pain and disability. Patients saw improvement in SF-12 physical component. Braces specifically designed to unload the degenerative compartment of the knee can be an effective treatment to decrease pain and maintain activity level to increase overall physical health.

Outcomes and revision rate after bone-patellar tendon-bone allograft versus autograft anterior cruciate ligament reconstruction in patients aged 18 years or younger with closed physes.

PURPOSE: The purpose of this study was to compare revision rates and outcomes after anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) autografts versus BPTB allografts in patients aged 18 years or younger with closed physes. METHODS: Institutional review board approval was obtained for this study. This study included 90 consecutive patients aged 18 years or younger with closed physes who underwent primary ACL reconstruction by a single surgeon between 1998 and 2009, with either BPTB autograft (n = 70) or BPTB allograft (n = 20). Patients who had concomitant ligament injuries were excluded. Outcome measures included the Lysholm score, Tegner activity scale, and patient satisfaction (0, very unsatisfied; 10, very satisfied). Failures were defined as cases requiring ACL revision surgery. RESULTS: Of the 90 patients, 79 (88%) were contacted (20 of 20 with allografts and 59 of 70 with autografts). Of these 79 patients, 9 (11%) required revision ACL reconstruction. In the autograft group, 3% (2 of 59) required revision ACL reconstruction at a mean of 15.4 months (range, 13.0 to 17.7 months) after the index procedure. In the allograft group, 35% (7 of 20) required revision ACL reconstruction at a mean of 9.1 months (range, 5.3 to 12.0 months) after the index procedure. The allograft group was 15 (95% confidence interval [CI], 2 to 123) times more likely to require revision reconstruction than the autograft group (P = .001). The mean Lysholm score at follow-up was 85 (95% CI, 80.4 to 90.3) for the autograft group and 91 (95% CI, 88.1 to 97.3) for the allograft group (P = .46). The median Tegner activity scale was 7.0 (95% CI, 6.9 to 8.0) for autograft group and 6.5 (95% CI, 4.9 to 8.4) for the allograft group (P = .27). Median patient satisfaction score was 10 of 10 in both cohorts. No failures were seen in either group at 2 years postoperatively. Five of seven allograft failures occurred because of a premature return to sports. CONCLUSIONS: No significant differences in function, activity, or satisfaction were found between allograft and autograft reconstructions in this patient population. The allograft group had a failure rate 15 times greater than that in the autograft group, with all failures occurring within the first year after reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Outcomes following healing response in older, active patients: a primary anterior cruciate ligament repair technique.

The purpose of this study was to document outcomes following the healing response procedure for treatment of complete, proximal anterior cruciate ligament (ACL) tears in a mature, active population. Healing response is an all-arthroscopic procedure that preserves the native ACL and makes use of an arthroscopic awl with a 45-degree angle to make holes in the femoral attachment of the ACL and in the body of the ACL. Patients were included in this IRB-approved study if they were > or =40 years old, had a complete proximal ACL tear, and who had healing response within 6 weeks of initial injury. In this study 48 patients (35 females, 13 males) with an average age of 51 years (range: 41 to 68 years) underwent the healing response procedure. Of these four female patients (8.9%) required subsequent ACL reconstruction. Mean time to ACL reconstruction was 34.5 months (range, 14.3 to 61.2 months). Of the 44, 41 patients (93%) had minimum of 2-year follow-up at an average of 7.6 years (range, 2.2 to 13.4 years). Average preoperative Lysholm score was 54 (range, 10 to 82) and improved to an average of 90 postoperatively (p = 0.001). Median Tegner activity scale at follow-up was 5 (range, 2 to 9). Median patient satisfaction was 10 (range, 4 to 10). Higher patient satisfaction was correlated with increased Lysholm score at follow-up (rho = 0.39, p = 0.02). Tegner activity scale was associated with postoperative Lysholm score (rho = 0.35, p = 0.04). This study demonstrates the effectiveness of the healing response procedure to allow patients to return to high levels of recreational activity and to restore knee function to normal levels. In a select group of mature patients with acute proximal ACL tears, the healing response procedure is an effective treatment technique.

Can Hylan G-F 20 with corticosteroid meet the expectations of osteoarthritis patients?

The purpose of this study was to document expectations and outcomes of active adults suffering from knee osteoarthritis (OA) who underwent treatment protocol of hyaluronic acid injection series with single injection of corticosteroid at initial injection. Our hypothesis was that patients would have functional improvement and pain relief following treatment, and that this treatment protocol will meet patients' expectations of treatment for knee OA. Forty-seven knees (range, 42-80 years) with a diagnosis of knee OA completed a self-administered questionnaire before and post injection series. Prior to injections, patients completed a validated expectation questionnaire and activity level questions. Following treatment, patients expected pain relief, to walk longer distances, and to increase activity level. Patients showed significant improvement in WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain subscale, comparing pre-injection and 6 months post-injection scores (P = .003) and overall WOMAC score (P = .038). SF-12 physical component significantly improved. Patients in this study expected to return to high levels of activity. Results showed significant improvement in pain relief and function. Our results supported that Hylan G-F 20 and corticosteroid are able to meet expectations of older patients with OA who desire to return to an active lifestyle. This study showed patient expectations do influence patient outcome scores and patient satisfaction.

Decreased femoral head-neck offset: a possible risk factor for ACL injury.

PURPOSE: Reduction in anterior cruciate ligament (ACL) injuries in young, active individuals continues to be a major goal in sports medicine. The purpose of this study was to determine the head-neck offset, as measured by AP pelvis alpha angles, in patients presenting to a single surgeon with isolated ACL and non-ACL knee injuries. METHODS: In a group of 48 patients with complete, primary ACL rupture and 42 controls with non-ACL injury (i.e., meniscus tear, cartilage defect), a single surgeon, blinded to the diagnosis, took radiographic measures of the AP alpha angle of both hips and the weight-bearing line at both knees. All knee pathology was confirmed with knee arthroscopy. Inclusion criteria included no previous hip or knee surgery, and long-leg standing alignment radiographic series completed at index visit. RESULTS: There was no difference in gender distribution, height, BMI or age between groups. ACL-injured patients had a significantly higher alpha angle (mean = 84, SD = 14) on the injured side than the controls (mean = 59, SD = 7, p < 0.0001). Ninety-four percent of the ACL-injured group had alpha angles over 60°, while only 35% of the non-ACL-injured group had alpha angles over 60° (p = 0.001). Those patients with alpha angle over 60° were 27 times more likely (95% CI 6.4-131) to be in the ACL injury group than those patients with alpha angle 60° or less (p = 0.001). CONCLUSION: Our findings establish an important preliminary correlation between ACL injury and diminished femoral head-neck offset, as characterized by abnormal, elevated alpha angles. LEVEL OF EVIDENCE: Prognostic study, Level III.

Effects of Platelet-Rich Plasma Composition on Anabolic and Catabolic Activities in Equine Cartilage and Meniscal Explants.

OBJECTIVE: To evaluate the effects of single- and double-spin preparations of platelet-rich plasma (PRP) on anabolic and catabolic activities of cartilage and meniscal explants in vitro. METHODS: Single- and double-spin PRP was prepared using laboratory processing or commercial kits. The cellular contents were quantified, and each PRP was mixed in equal quantities with cell culture medium and added to cartilage or meniscus explant cultures, with or without interleukin 1 ß (IL-1ß). Extracellular matrix synthesis was quantified over 24 hours via (35)S-sulfate and (3)H-proline incorporation, while gene expression of catabolic enzymes was evaluated using real-time PCR. RESULTS: The platelet concentration in single-spin laboratory PRP was 59% higher than blood. Platelet and white blood cell concentrations in single-spin laboratory and kit PRP were not significantly different, while the double-spin kit resulted in approximately 2.5-fold higher platelet and approximately 400-fold higher white blood cell concentrations. In cartilage cultures without IL-1ß, radiolabel incorporation in single-spin PRP cultures was significantly higher than in double-spin cultures. Similar results were obtained for (35)S-sulfate incorporation in meniscus cultures without IL-1ß. In IL-1ß, radiolabel incorporation was largely similar among all PRPs. After 24 hours of culture, ADAMTS-4 gene expression in cartilage was lowest for single-spin PRP, while expression in the double-spin kit was not significantly different from double-spin laboratory PRP in which platelets were concentrated 6-fold. CONCLUSIONS: This study suggests that single-spin PRP preparations may be the most advantageous for intra-articular applications and that double-spin systems should be considered with caution.

In vivo tibiofemoral kinematics during 4 functional tasks of increasing demand using biplane fluoroscopy.

BACKGROUND: The anterior cruciate ligament (ACL) has been well defined as the main passive restraint to anterior tibial translation (ATT) in the knee and plays an important role in rotational stability. However, it is unknown how closely the ACL and other passive and active structures of the knee constrain translations and rotations across a set of functional activities of increasing demand on the quadriceps. HYPOTHESIS: Anterior tibial translation and internal rotation of the tibia relative to the femur would increase as the demand on the quadriceps increased. STUDY DESIGN: Controlled laboratory study. METHODS: The in vivo 3-dimensional knee kinematics of 10 adult female patients (height, 167.8 ± 7.1 cm; body mass, 57 ± 4 kg; body mass index [BMI], 24.8 ± 1.7 kg/m(2); age, 29.7 ± 7.9 years) was measured using biplane fluoroscopy while patients completed 4 functional tasks. The tasks included an unloaded knee extension in which the patient slowly extended the knee from 90° to 0° of flexion in 2 seconds; walking at a constant pace of 90 steps per minute; a maximum effort isometric knee extension with the knee at 70° of flexion; and landing from a height of 40 cm in which the patient stepped off a box, landed, and immediately performed a maximum effort vertical jump. RESULTS: Landing (5.6 ± 1.9 mm) produced significantly greater peak ATT than walking (3.1 ± 2.2 mm) and unweighted full extension (2.6 ± 2.1 mm) (P < .01), but there was no difference between landing and a maximum isometric contraction (5.0 ± 1.9 mm). While there was no significant difference in peak internal rotation between landing (19.4° ± 5.7°), maximum isometric contraction (15.9° ± 6.7°), and unweighted full knee extension (14.5° ± 7.7°), each produced significantly greater internal rotation than walking (3.9° ± 4.2°) (P < .001). Knee extension torque significantly increased for each task (P < .01): unweighted knee extension (4.7 ± 1.2 N·m), walking (36.5 ± 7.9 N·m), maximum isometric knee extension (105.1 ± 8.2 N·m), and landing (140.2 ± 26.2 N·m). CONCLUSION: Anterior tibial translations significantly increased as demand on the quadriceps and external loading increased. Internal rotation was not significantly different between landing, isometric contraction, and unweighted knee extension. Additionally, ATT and internal rotation from each motion were within the normal range, and no excessive amounts of translation or rotation were observed. CLINICAL RELEVANCE: This study demonstrated that while ATT will increase as demand on the quadriceps and external loading increases, the knee is able to effectively constrain ATT and internal rotation. This suggests that the healthy knee has a safe envelope of function that is tightly controlled even though task demand is elevated.

Relationship of knee shear force and extensor moment on knee translations in females performing drop landings: a biplane fluoroscopy study.

BACKGROUND: Research has linked knee extensor moment and knee shear force to the non-contact anterior cruciate ligament injury during the landing motion. However, how these biomechanical performance factors relate to knee translations in vivo is not known as knee translations cannot be obtained with traditional motion capture techniques. The purpose of this study was to combine traditional motion capture with high-speed, biplane fluoroscopy imaging to determine relationships between knee extensor moment and knee shear force profiles with anterior and lateral tibial translations occurring during drop landing in female athletes. METHODS: 15 females performed drop landings from a height of 40 cm while being recorded using a high speed, biplane fluoroscopy system and simultaneously being recorded using surface marker motion capture techniques to estimate knee joint angle, reaction force and moment profiles. FINDINGS: No significant statistical relationships were observed between peak anterior or posterior knee shear force and peak anterior and lateral tibial translations; or, between peak knee extensor moment and peak anterior and lateral tibial translations. Although differences were noted in peak shear force (P=0.02) and peak knee extensor moment (P<0.001) after stratification into low and high shear force and moment cohorts, no differences were noted in anterior and lateral tibial translations (all P ≥ 0.18). INTERPRETATION: Females exhibiting high knee extensor moment and knee shear force during drop landings do not yield correspondingly high anterior and lateral tibial translations.

Evaluation of intra-articular mesenchymal stem cells to augment healing of microfractured chondral defects.

PURPOSE: This study evaluated intra-articular injection of bone marrow-derived mesenchymal stem cells (BMSCs) to augment healing with microfracture compared with microfracture alone. METHODS: Ten horses (aged 2.5 to 5 years) had 1-cm2 defects arthroscopically created on both medial femoral condyles of the stifle joint (analogous to the human knee). Defects were debrided to subchondral bone followed by microfracture. One month later, 1 randomly selected medial femorotibial joint in each horse received an intra-articular injection of either 20 × 10(6) BMSCs with 22 mg of hyaluronan or 22 mg of hyaluronan alone. Horses were confined for 4 months, with hand walking commencing at 2 weeks and then increasing in duration and intensity. At 4 months, horses were subjected to strenuous treadmill exercise simulating race training until completion of the study at 12 months. Horses underwent musculoskeletal and radiographic examinations bimonthly and second-look arthroscopy at 6 months. Horses were euthanized 12 months after the defects were made, and the affected joints underwent magnetic resonance imaging and gross, histologic, histomorphometric, immunohistochemical, and biochemical examinations. RESULTS: Although there was no evidence of any clinically significant improvement in the joints injected with BMSCs, arthroscopic and gross evaluation confirmed a significant increase in repair tissue firmness and a trend for better overall repair tissue quality (cumulative score of all arthroscopic and gross grading criteria) in BMSC-treated joints. Immunohistochemical analysis showed significantly greater levels of aggrecan in repair tissue treated with BMSC injection. There were no other significant treatment effects. CONCLUSIONS: Although there was no significant difference clinically or histologically in the 2 groups, this study confirms that intra-articular BMSCs enhance cartilage repair quality with increased aggrecan content and tissue firmness. CLINICAL RELEVANCE: Clinical use of BMSCs in conjunction with microfracture of cartilage defects may be potentially beneficial.

Measurements of tibiofemoral kinematics during soft and stiff drop landings using biplane fluoroscopy.

BACKGROUND: Previous laboratory studies of landing have defined landing techniques in terms of soft or stiff landings according to the degree of maximal knee flexion angle attained during the landing phase and the relative magnitude of the ground-reaction force. Current anterior cruciate ligament injury prevention programs are instructing athletes to land softly to avoid excessive strain on the anterior cruciate ligament. PURPOSE: This study was undertaken to measure, describe, and compare tibiofemoral rotations and translations of soft and stiff landings in healthy individuals using biplane fluoroscopy. STUDY DESIGN: Controlled laboratory study. METHODS: The in vivo, lower extremity, 3-dimensional knee kinematics of 16 healthy adults (6 male and 10 female) instructed to land softly and stiffly in different trials were collected in biplane fluoroscopy as they performed the landing from a height of 40 cm. RESULTS: Average and maximum relative anterior tibial translation (average, 2.8 ± 1.2 mm vs 3.0 ± 1.4 mm; maximum, 4.7 ± 1.6 mm vs 4.4 ± 0.8 mm), internal/external rotation (average, 3.7° ± 5.1° vs 2.7° ± 4.3°; maximum, 5.6° ± 5.5° vs 4.9° ± 4.7°), and varus/valgus (average, 0.2° ± 1.2° vs 0.2° ± 1.0°; maximum, 1.7° ± 1.2° vs 1.6° ± 0.9°) were all similar between soft and stiff landings, respectively. The peak vertical ground-reaction force was significantly larger for stiff landings than for soft landings (2.60 ± 1.32 body weight vs 1.63 ± 0.73; P < .001). The knee flexion angle total range of motion from the minimum angle at contact to the maximum angle at peak knee flexion was significantly greater for soft landings than for stiff (55.4° ± 8.8° vs 36.8° ± 11.1°; P < .01). CONCLUSION: Stiff landings, as defined by significantly lower knee flexion angles and significantly greater peak ground-reaction forces, do not result in larger amounts of anterior tibial translation or knee rotation in either varus/valgus or internal/external rotation in healthy individuals. CLINICAL RELEVANCE: In healthy knees, the musculature and soft tissues of the knee are able to maintain translations and rotations within a small, safe range during controlled landing tasks of differing demand. The knee kinematics of this healthy population will serve as a comparison for injured knees in future studies. It should be stressed that because the authors did not compare how the loads were distributed over the soft tissues of the knee between the 2 landing styles, the larger ground-reaction forces and more extended knee position observed during stiff landings should still be considered dangerous to the anterior cruciate ligament and other structures of the lower extremities, particularly in competitive settings where movements are often unanticipated.

Knee kinematic profiles during drop landings: a biplane fluoroscopy study.

INTRODUCTION: The six degrees of freedom knee motion during dynamic activities is not well understood. PURPOSE: Biplane fluoroscopy was used to measure the three-dimensional rotations and translations of healthy knees during stiff drop landings and to determine the relationships between three-dimensional rotations and anterior (ATT) and lateral tibial translations (LTT). METHODS: Six males performed stiff drop landings from 40 cm while being filmed using a high-speed, biplane fluoroscopy system. Initial, peak, and excursions for rotations and translations were calculated, and relationships and changes in these variables were assessed (α = 0.05). RESULTS: Knee flexion at contact was 13.9° ± 9.2° (mean ± SD) and increased to a peak of 44.0° ± 17.2° with an excursion of 31.5° ± 14.1°. Knee varus/valgus angle at contact was -0.3° ± 1.8° varus; subjects progressed into a mean peak valgus position of 1.5° ± 0.9° with total excursion of 2.5° ± 0.9°. Four of six subjects landed externally rotated (2.5° ± 3.0°); two landed internally rotated (-4.9° ± 1.5°), yielding a contact angle of -2.4° ± 3.0° of internal rotation, a peak internal rotation of -5.5° ± 6.0°, and excursion of 3.1° ± 5.5°. Peak ATT were 4.3 ± 0.7 mm (excursion = 2.1 ± 0.9 mm), occurring within 50 ms after contact. Peak LTT were 1.5 ± 1.4 mm (excursion = 2.6 ± 1.6 mm). Significant regressions were found between ATT and knee valgus angle (r2 = 0.39, P = 0.006), between LTT and internal rotation (r2 = 0.96, P < 0.0001), and between LTT and knee valgus angle (quadratic, r2 = 0.90, P < 0.0001). CONCLUSION: This study provides a direct correlation between knee valgus angle with knee ATT and LTT during drop landings.

The inter-rater reliability and diagnostic accuracy of patellar mobility tests in patients with anterior knee pain.

BACKGROUND: Patients with patellofemoral pain syndrome (PFPS) often have nonspecific findings on clinical examination. A tight knee and diminished patellar mobility in particular, may contribute to anterior knee pain. METHODS: Qualifying patients with anterior knee pain of > 4 weeks were sequentially examined by 2 physicians who used the patellar mobility tests. The tests evaluated for diminished patellar translation superior-inferiorly and medial-laterally, diminished patellar tendon mobility, and absent inferior pole tilt. Each of the 4 tests was scored as 1 (diminished/absent) or 0 (nondiminished/normal), with the sum of the scores determining the patellar mobility scale. Inter-rater reliability and diagnostic accuracy were determined and analyzed. Receiver operating characteristic analysis was used to determine the capacity of the patellar mobility scale to predict PFPS. RESULTS: 98 patients participated in the study. The inter-rater reliability for the 4 individual patellar mobility tests was moderately strong, with diminished medial-lateral patellar mobility demonstrating the strongest reliability (Kappa value [K], 0.59; 95% confidence interval [CI], 0.42-0.72), followed by diminished superior-inferior mobility (K), 0.55; 95% CI, -0.37 to 0.69), inferior pole tilt (K, 0.48; 95% CI, -0.28 to 0.61), and patellar tendon mobility (K, 0.45; 95% CI, -0.27 to 0.56). The diagnostic accuracy of the individual patellar mobility tests in diagnosing PFPS was fair to moderate, with the individual diminished patella tendon mobility test having the highest level of diagnostic accuracy (sensitivity, 49%; specificity, 83%; likelihood ratio [LR] ± 2.8; 95% CI, 1.3-7.3) and also having the highest positive predictive value (0.88). Diminished medial-lateral mobility was second in diagnostic accuracy (sensitivity, 54%; specificity, 69%; LR ± 1.8; 95% CI, 0.9-3.6). Receiver operating characteristic analysis showed only moderate levels of diagnostic capacity (area under the curve, 0.65) because combining all 4 patellar mobility tests to form the patellar mobility scale did not improve the diagnostic accuracy. CONCLUSION: The clinical importance of diminished patellar and/or patellar tendon mobility findings in the evaluation of patients with anterior knee pain remains unclear. We determined that individual patellar mobility tests had moderate levels of inter-rater reliability, the best agreement found with medial-lateral mobility. The accuracy of the patellar mobility scale for diagnosing PFPS was marginal. As a tool, this cluster of examination techniques may be used by physicians to better understand their patients' conditions and descriptively communicate their findings. However, the patellar mobility scale cannot be used alone for determining the diagnosis of PFPS, as defined in our study. Future studies aim to determine whether post-treatment symptomatic improvements correlate with an improvement on the patellar mobility scale.

Chondral resurfacing and high tibial osteotomy in the varus knee: survivorship analysis.

BACKGROUND: Active patients with arthritic malalignment of the knee are difficult to manage. Arthroplasty, unicompartmental or total knee replacement, may not be appropriate in patients who desire to remain highly active. High tibial osteotomy has been recommended for the treatment of varus osteoarthritis to decrease pressure on the damaged medial compartment. PURPOSE: To determine the length of time patients with varus gonarthrosis can avoid knee arthroplasty with chondral resurfacing (microfracture) and medial opening wedge high tibial osteotomy (HTO). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From 1995 to 2001, the senior authors performed a medial opening wedge HTO/microfracture in 106 knees (mean age, 52 years; range, 30-71 years). Survivorship was defined as not requiring knee arthroplasty after microfracture and HTO. RESULTS: At 5 years, survivorship was 97%. At 7 years, survivorship was 91%. Twelve patients proceeded to arthroplasty at a mean of 81 months (range, 19-116 months). Follow-up was obtained for 90% of patients. At most recent follow-up, the mean Lysholm score was 71 (range, 5-100). At 3 years, the mean Lysholm score was 73, Tegner score was 2.8, and patient satisfaction was 7.9. At 5 years, the mean Lysholm score was 73, Tegner score was 3.8, and patient satisfaction was 7.5. At 9 years, the mean Lysholm score was 67, Tegner score was 3.1, and patient satisfaction was 7.5. Patients with medial meniscus injury at surgery were 9.2 times more likely to undergo arthroplasty than patients without (95% confidence interval [CI], 1.4-13.5; P = .015). CONCLUSION: With 91% survivorship at 7 years, microfracture/HTO seems to contribute to a delay of knee replacement in active patients with varus gonarthrosis. Patients who proceeded to knee arthroplasty after combined HTO/microfracture had a mean delay of 81.3 months.