Knee dislocations: where are the lesions? A prospective evaluation of surgical findings in 63 cases

OBJECTIVE

To evaluate soft-tissue injury patterns in a large series of patients with knee dislocations to identify frequency and associations that may aid in surgical planning.

DESIGN

Prospective clinical study.

SETTING

Two institutions, both level I trauma centers.

PATIENTS

Sixty patients with 63 dislocatable knees.

RESULTS

Cause of injury was motor vehicle injury in 34 patients, sports in 23 patients, and falls in 3 patients; 71% of knees studied had bicruciate injuries. Eight knees had associated major intraarticular fractures. Vascular disruption occurred in 14% of knees. Peroneal nerve palsies occurred in 14% of knees. All injured knees with complete peroneal nerve palsies had anterior cruciate ligament, posterior cruciate ligament, and lateral collateral ligament disruptions. The incidence of vascular injury was the same for patients injured in sports as for those injured in road trauma. Reattachable ligamentous avulsions occurred in 19% for anterior cruciate ligament, 51% for posterior cruciate ligament, 64% for medial collateral ligament, and 84% for lateral collateral ligament injuries. Certain injury patterns also had a high association of tendon and capsule avulsions. Proximal lateral collateral ligament injuries were commonly associated with popliteus tendon avulsions and seldom with distal biceps avulsions. Distal lateral collateral ligament injuries were commonly associated with distal biceps avulsions and seldom with popliteus tendon avulsions. Reattachable meniscal capsular avulsions off the tibia occurred predominantly when the collateral ligament injury was a distal avulsion.

CONCLUSIONS

This study showed a wide variety of injury patterns. Knees had to have at least two ligaments injured to be dislocatable but not necessarily both cruciate ligaments. Sports injuries have the same pattern of injury as motor vehicle accidents, suggesting similar forces of injury. The study demonstrates a high incidence of reattachable avulsion injuries to ligaments and soft tissues in dislocatable knees. These may not be as easily dealt with if surgery is delayed beyond 3-4 weeks.

Knee stability and graft function following anterior cruciate ligament reconstruction: Comparison between 11 o'clock and 10 o'clock femoral tunnel placement. 2002 Richard O'Connor Award paper

PURPOSE

To study how well an anterior cruciate ligament (ACL) graft fixed at the 10 and 11 o'clock positions can restore knee function in response to both externally applied anterior tibial and combined rotatory loads by comparing the biomechanical results with each other and with the intact knee.

TYPE OF STUDY

Biomechanical experiment using human cadaveric specimens.

METHODS

Ten human cadaveric knees (age, 41+/-13 years) were reconstructed by placing a bone-patellar tendon-bone graft at the 10 and 11 o'clock positions, in a randomized order, and then tested using a robotic/universal force-moment sensor testing system. Two external loading conditions were applied: (1) 134 N anterior tibial load with the knee at full extension, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion, and (2) a combined rotatory load of 10 N-m valgus and 5 N-m internal tibial torque with the knee at 15 degrees and 30 degrees of flexion. The resulting kinematics of the reconstructed knee and in situ forces in the ACL graft were determined for each femoral tunnel position.

RESULTS

In response to a 134-N anterior tibial load, anterior tibial translation (ATT) for both femoral tunnel positions was not significantly different from the intact knee except at 90 degrees of knee flexion as well as at 60 degrees of knee flexion for the 10 o'clock position. There was no significant difference in the ATT between the 10 and 11 o'clock positions, except at 90 degrees of knee flexion. Under a combined rotatory load, however, the coupled ATT for the 11 o'clock position was approximately 130% of that for the intact knee at 15 degrees and 30 degrees of flexion. For the 10 o'clock position, the coupled ATT was not significantly different from the intact knee at 15 degrees of flexion and approximately 120% of that for the intact knee at 30 degrees of flexion. Coupled ATT for the 10 o'clock position was significantly smaller than for the 11 o'clock position at 15 degrees and 30 degrees of flexion. The in situ force in the ACL graft was also significantly higher for the 10 o'clock position than the 11 o'clock position at 30 degrees of flexion in response to the same loading condition (70 +/- 18 N v 60 +/- 15 N, respectively).

CONCLUSIONS

The 10 o'clock position more effectively resists rotatory loads when compared with the 11 o'clock position as evidenced by smaller ATT and higher in situ force in the graft. Despite the fact that ACL grafts placed at the 10 or 11 o'clock positions are equally effective under an anterior tibial load, neither femoral tunnel position was able to fully restore knee stability to the level of the intact knee.

The fixation strength of six hamstring tendon graft fixation devices in anterior cruciate ligament reconstruction. Part II: tibial site

BACKGROUND

Tibial fixation is more problematic than femoral fixation in anterior cruciate ligament reconstruction.

HYPOTHESIS

There is no difference in initial fixation strength among hamstring tendon graft tibial fixation devices.

STUDY DESIGN

Randomized experimental study.

METHODS

Each of six devices used to fix 120 quadrupled human semitendinosus-gracilis tendon grafts into porcine tibiae was tested 10 times with a single-cycle load-to-failure test and 10 times with a 1500-cycle loading test. Specimens surviving cyclic loading were subjected to a single-cycle load-to-failure test.

RESULTS

Intrafix (1332 N) was the strongest in the single-cycle load-to-failure test, followed by WasherLoc (975 N), tandem spiked washer (769 N), SmartScrew ACL (665 N), BioScrew (612 N), and SoftSilk (471 N). After cyclic-loading tests, Intrafix showed the lowest residual displacement (1.5 mm) and was also strongest (1309 N) in the single-cycle load-to-failure test after the cyclic-loading test, followed by WasherLoc (3.2 mm; 917 N).

CONCLUSION

The Intrafix provided clearly superior strength in the fixation of hamstring tendon grafts to the tibial drill hole.

CLINICAL RELEVANCE

Some caution may be warranted when using the implants that showed increased residual displacement, especially if aggressive rehabilitation is to be used. Preconditioning of the hamstring tendon graft-implant complex before tibial fixation is needed.

Septic arthritis caused by Erysipelothrix rhusiopathiae infection after arthroscopically assisted anterior cruciate ligament reconstruction

A case of septic arthritis caused by Erysipelothrix rhusiopathiae, after an arthroscopically assisted anterior cruciate ligament (ACL) substitution in a non-immunosuppressed patient is described. An 18-year-old man underwent an ACL reconstruction with a quadruple hamstring graft. Eight days postoperatively, the patient developed fever, knee pain, and effusion without erythema or suppuration. He was readmitted to the hospital with the diagnosis of septic arthritis. The patient's erythrocyte sedimentation rate, C-reactive protein level, and white blood cell count were high. The joint was aspirated and the fluid was sent for cultures that revealed the presence of E rhusiopathiae. E rhusiopathiae is widespread in nature, it is transmitted by direct cutaneous laceration, and it causes septic arthritis, meningitis, endocarditis, and renal failure in immunosuppressed people with poor prognosis. In our case, the infection was treated with arthroscopic lavage and debridement, retention of the graft and hardware, and intravenous antibiotic administration for 6 weeks, followed by oral administration for 16 weeks.

Jump landing strategies in male and female college athletes and the implications of such strategies for anterior cruciate ligament injury

BACKGROUND

Female athletes are more likely than male athletes to injure the anterior cruciate ligament. Causes of this increased injury incidence in female athletes remain unclear, despite numerous investigations.

HYPOTHESIS

Female athletes will exhibit lower hamstring muscle activation and smaller knee flexion angles than male athletes during jump landings, especially when the knee muscles are fatigued.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight female and six male varsity college basketball athletes with no history of knee ligament injury performed jump landings on the dominant leg from a maximum height jump and from 25.4 cm and 50.8 cm high platforms under nonfatigued and fatigued conditions. Knee joint angle and surface electromyographic signals from the quadriceps, hamstring, and gastrocnemius muscles were recorded.

RESULTS

Women landed with greater knee flexion angles and greater knee flexion accelerations than men. Knee muscle activation patterns were generally similar in men and women.

CONCLUSION

As compared with male college basketball players, female college basketball players did not exhibit altered knee muscle coordination characteristics that would predispose them to anterior cruciate ligament injury when landing from jumps. This conclusion is made within the parameters of this study and based on the observation that hamstring muscle activation was similar for both groups. The greater knee flexion we observed in the female subjects would be expected to decrease their risk of injury.

CLINICAL RELEVANCE

Factors other than those evaluated in this study need to be considered when attempting to determine the reasons underlying the increased incidence of anterior cruciate ligament injuries consistently observed in elite female athletes.

Arthroscopic anterior cruciate ligament reconstruction: An air-fluid medium to enhance visual clarity

We describe a surgical technique that has been used successfully during arthroscopic anterior cruciate ligament reconstruction to enhance the visual clarity of the operating field specifically during tunnel placement. The precise siting of both tibial and femoral tunnels is critical to both the short- and long-term success of this procedure. Gentle insufflation of the knee joint with air prior to tunnel siting allows for an excellent view of the intercondylar notch. This visual clarity helps in the precise placement and measurement of the femoral tunnel.

Radiologic case study. Traumatic dislocation of the knee

Imaging in knee dislocation requires multiple modalities and a comprehensive assessment of ligaments, cartilage, bone, nerve, and vascular anatomy. Magnetic resonance imaging is essential in the work-up of these patients and MRA is a promising modality for detecting vascular injury.

Restoration of anterior cruciate ligament-hamstring reflex arc after anterior cruciate ligament reconstruction

It has recently been emphasized that restoration of neuromuscular function contributes to dynamic stability of the anterior cruciate ligament (ACL) reconstructed knee. The existence of an ACL-hamstring reflex arc, one of the protective ligament-muscular pathways, has been revealed in normal human knees. Although reinnervation to the reconstructed ACL has been observed histologically, it remains unclear whether the ACL-hamstring reflex arc is reestablished. This study examined the existence of the ACL-hamstring reflex arc in ACL-reconstructed knees by analyzing the changes in the hamstring EMG elicited by electrical stimulation to the reconstructed ACL. The patellar tendon grafts transplanted as an ACL substitute in three patients were electrically stimulated via a bipolar wire electrode inserted arthroscopically. The surface EMG was monitored from the ipsilateral biceps femoris and semitendinosus. In two of the three patients the significantly increased EMG value of the biceps femoris was detected between 120 and 140 ms after the onset of electrical ACL stimulation. The increased EMG activity detected in the biceps femoris after the stimulation to the patellar tendon graft indicated reestablishment of the ACL-hamstring reflex arc in the ACL-reconstructed knee.

Dynamics of muscle strength improvement during isokinetic rehabilitation of athletes with ACL rupture and chondromalacia patellae

AIM

To assess quantitatively dynamics and extent of the increase in muscle strength during isokinetic rehabilitation.

METHODS

EXPERIMENTAL DESIGN

daily measurements of muscle strength; detailed testing at the beginning and at the end of rehabilitation.

SETTING

Cybex Rehabilitation Center, Zagreb.

SUBJECTS

44 athletes (31 m, 13 F, age 16-35), 3 injury-defined groups: athletes with ACL rupture (non-reconstructed and reconstructed) and chondromalacia patellae.

INTERVENTIONS

all subjects underwent isokinetic rehabilitation on Cybex Orthotron KT2 device, using individually designed protocols (extension and flexion exercises, concentric muscle contractions, 15 treatments).

MEASUREMENTS

monitoring of daily progress on rehabilitation device and detailed testing on diagnostic device.

RESULTS

All patients showed considerable improvement. Muscle strength improved on average 141% (SD=110) in ACL-reconstructed group, 144% (SD=130) for chondromalacia patellae group and 150% (SD=74) for ACL-non-reconstructed group, comparing to initial strength. Dynamic status tested on Cybex Otrhotron diagnostic device prior and after rehabilitation strongly correlated with final progress monitored on the rehabilitation device.

CONCLUSION

Isokinetic rehabilitation is a quick and effective method in treating knee injuries in athletes. Both types of objective criteria have shown significant increase in muscle strength. The improvement of muscle strength was on the average 149% (SD=101), which is about 10% daily for 15 treatments. The greatest progress, 19% per day, occurred during first five days. The athletes were able to resume their sport activities as follows: patients from chondromalacia patellae group, and most of them from the non-reconstructed ACL group were back in competition within a month, while 75% from the ACL reconstructed group came back within 3 months, and the rest of them within 5 months.

MR imaging of the menisci and cruciate ligaments: a systematic review

PURPOSE

To systematically review and synthesize published data on the diagnostic performance of magnetic resonance (MR) imaging of the menisci and cruciate ligaments and to assess the effect of study design characteristics and magnetic field strength on diagnostic performance.

MATERIALS AND METHODS

Articles published between 1991 and 2000 were included if at least 30 patients were studied, arthroscopy was the reference standard, the magnetic field strength was reported, positivity criteria were defined, and the absolute numbers of true-positive, false-negative, true-negative, and false-positive results were available or derivable. Pooled weighted and summary receiver operating characteristic (ROC) analyses were performed for tears of both menisci and both cruciate ligaments separately and for the four lesions combined, by using random effects models. Differences were assessed according to lesion type.

RESULTS

Twenty-nine of 120 retrieved articles were included. Pooled weighted sensitivity was higher for medial meniscal tears than that for lateral meniscal tears. However, pooled weighted specificity for the medial meniscus was lower than that for the lateral meniscus. In summary ROC analyses performed per lesion, various study design characteristics were found to influence diagnostic performance. Higher magnetic field strength significantly improved discriminatory power only for anterior cruciate ligament tears. When all lesions were combined in one overall summary ROC analysis, magnetic field strength was a significant but modest predictor of diagnostic performance.

CONCLUSION

Diagnostic performance of MR imaging of the knee is different according to lesion type and is influenced by various study design characteristics. Higher magnetic field strength modestly improves diagnostic performance, but a significant effect was demonstrated only for anterior cruciate ligament tears.

Comparison of outcomes between males and females after anterior cruciate ligament reconstruction

Few studies have specifically addressed the potential differences in outcome from ACL reconstruction between males and females. The present study compared patient-reported outcomes between the sexes after a minimum of 2 years following arthroscopic ACL reconstruction using bone-patellar tendon-bone autograft. Patients were also categorized as acute or chronic based on the time from injury to surgery. Outcome questionnaires were mailed to 638 patients, resulting in 151 eligible respondents included in the analysis. The outcome instruments used were the Cincinnati scale, the ACL-Quality of Life scale, and the Tegner activity rating scale. At an average of 5 years following ACL reconstruction no differences were found between males (n=74) and females (n=77) on the ACL-QOL scale. Females perceived a significantly higher activity level prior to surgery according to the Tegner scale. However, no other differences were identified by gender or stage based on prior, highest, or current Tegner activity levels. Results of the Cincinnati scale for the entire sample showed that females scored an average of 5.7 points lower than males. Analysis of this difference by patient age indicates a trend toward lower scores in females between 12-18 and over 24 years old. Chronicity was not a factor that affected outcome in either males or females. No differences were found in the number of patients who complained of anterior knee pain. We conclude that autogenous bone-patella tendon-bone ACL reconstruction is equally successful in well-matched populations of males and females.

Comparison of sagittal obliquity of the reconstructed anterior cruciate ligament with native anterior cruciate ligament using magnetic resonance imaging

PURPOSE

This study was conducted to compare the obliquity of asymptomatic anterior cruciate ligament (ACL) grafts with normal controls using sagittal magnetic resonance imaging (MRI).

TYPE OF STUDY

Case control study.

METHODS

Sagittal MRIs from 30 patients with a reconstructed ACL graft and from 30 individuals with an intact ACL were reviewed. Reconstructed patients were operated on with a 2-incision technique using a patellar tendon autograft. These selected patients had a normal or nearly normal IKDC score with a 3 mm or less anterior posterior translation on KT-1000 arthrometer testing compared with the intact knee. MRI showed a continuous and homogeneous graft without evidence of roof impingement. Obliquity of the grafted ACL was determined on each lateral MRI by measuring the intersection of the graft line with the tibial plateau plane. These figures were compared with data similarly obtained from 30 individuals with a stable knee and an intact ACL determined by history and physical examination.

RESULTS

Graft obliquity in reconstructed patients averaged 67 degrees with a range between 55 degrees and 81 degrees. In normal controls, intact ACL obliquity averaged 51 degrees with a range between 45 degrees and 55 degrees. The difference between the two groups was statistically significant (P <.0001).

CONCLUSIONS

MRIs of patients with an appropriate tibial tunnel placement in order to avoid notch impingement showed a continuous and homogeneous graft similar to the native ACL, but with a more vertical graft that does not recreate the normal sagittal obliquity. However, according to arthrometer testing, these more vertical grafts can control anterior posterior knee displacement.

The use of intraoperative fluoroscopy to reduce femoral interference screw divergence during endoscopic anterior cruciate ligament reconstruction

Femoral interference screw divergence can potentially have detrimental consequences in the rehabilitation of anterior cruciate ligament (ACL) reconstruction. Several biomechanical studies suggest that divergence angles greater than 15 degrees significantly decrease the pullout strength of the graft. Numerous techniques have been described in the literature that address this issue; however, the use of an image intensifier intraoperatively is not frequently discussed. We describe a technique in which fluoroscopy is used to confirm the proper position of the femoral interference screw at the time of the procedure, and therefore minimizes the incidence of significant screw divergence. Radiographic analysis of 62 patients who underwent endoscopic ACL reconstruction using bone-patellar tendon-bone autograft using this technique revealed significant divergence in only 3% of patients.

Acute grade III medial collateral ligament injury of the knee associated with anterior cruciate ligament tear. The usefulness of magnetic resonance imaging in determining a treatment regimen

BACKGROUND

The appropriate management of acute grade III medial collateral ligament injury when it is combined with a torn anterior cruciate ligament has not been determined.

HYPOTHESIS

Magnetic resonance imaging grading of grade III medial collateral ligament injury in patients who also have anterior cruciate ligament injury correlates with the outcome of their nonoperative treatment.

STUDY DESIGN

Prospective cohort study.

METHODS

Seventeen patients were first treated nonoperatively with bracing. Eleven patients with restored valgus stability received anterior cruciate ligament reconstruction only, and six with residual valgus laxity also received medial collateral ligament surgery.

RESULTS

Magnetic resonance imaging depicted complete disruption of the superficial layer of the medial collateral ligament in all 17 patients and disruption of the deep layer in 14. Restoration of valgus stability was significantly correlated with the location of superficial fiber damage. Damage was evident over the whole length of the superficial layer in five patients, and all five patients had residual valgus laxity despite bracing. Both groups had good-to-excellent results 5 years later.

CONCLUSIONS

Location of injury in the superficial layer may be useful in predicting the outcome of nonoperative treatment for acute grade III medial collateral ligament lesions combined with anterior cruciate ligament injury.

Comparison of three techniques of anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft. Differences in anterior tibial translation and tunnel enlargement with each technique

BACKGROUND

Anatomic fixation of the graft in anterior cruciate ligament reconstruction has improved stability of the reconstructed knee joint in experimental studies.

HYPOTHESIS

Anatomic fixation of the bone-patellar tendon-bone autograft will reduce tunnel enlargement and improve clinical results.

STUDY DESIGN

Prospective cohort study.

METHODS

Sixty patients were randomly divided into three groups: a nonanatomic fixation group (traditional single-incision reconstruction), an anatomic fixation group (reconstruction in which a bone plug was grafted into the tibial tunnel), and an anatomic fixation group with all-inside reconstruction. Stability of the knee joint was examined with a KT-1000 arthrometer at 2, 4, 6, 12, and 24 months after surgery. At 12 months, anteroposterior and lateral radiographs were made to assess tunnel enlargement.

RESULTS

Although the magnitude of tibial displacement gradually increased after reconstruction in all three groups, the anatomic fixation group had significantly better stability than the groups undergoing nonanatomic fixation or all-inside anatomic fixation at 4 and 6 months after anterior cruciate ligament reconstruction. However, there was no significant difference between the three groups at 24 months. Regarding the tibial tunnel, residual rates and enlargement of tunnels were different between the reconstruction techniques. The nonanatomic reconstruction group had significantly greater tunnel enlargement.

CONCLUSION

Anatomic fixation of the graft decreased the tunnel enlargement but had no effect on knee stability at 2-year follow-up.

The fixation strength of six hamstring tendon graft fixation devices in anterior cruciate ligament reconstruction. Part I: femoral site

BACKGROUND

Strength of graft fixation is the weakest link in anterior cruciate ligament reconstruction.

HYPOTHESIS

There is no difference in initial fixation strength between different hamstring tendon graft femoral fixation devices.

STUDY DESIGN

Randomized experimental study.

METHODS

Each of six devices was used in the fixation of 10 quadrupled human semitendinosus-gracilis tendon grafts in tunnels drilled in porcine femora and tested 10 times with a single-cycle load-to-failure test at a rate of 50 mm/min and 10 times with a 1500-cycle loading test between 50 and 200 N at one cycle every 2 seconds. The specimens that survived the cyclic loading were subjected to a single-cycle load-to-failure test.

RESULTS

The Bone Mulch Screw (1112 N) was strongest in the single-cycle load-to-failure test, followed by EndoButton CL (1086 N), RigidFix (868 N), SmartScrew ACL (794 N), BioScrew (589 N), and RCI screw (546 N). It also showed the lowest residual displacement (2.2 mm) and was strongest in the single-cycle load-to-failure test after cyclic loading.

CONCLUSIONS

The Bone Mulch Screw was superior to all other devices.

CLINICAL RELEVANCE

Caution may be warranted in employing aggressive rehabilitation after reconstruction with these devices. Preconditioning of the graft-implant complex before fixation is important.

Tensile properties of an anterior cruciate ligament graft after bone-patellar tendon-bone press-fit fixation

Hardware used for fixation of ACL autografts in bone tunnels frequently complicates revision surgery, requiring two-stage procedures when a bone-patellar tendon-bone (B-PT-B) autograft is used for ACL reconstruction. Therefore alternative procedures that eliminate hardware have been advocated. This study compared the mechanical behavior of two fixation procedures: a widely used interference screw (IFS) fixation and a press-fit fixation that is hardware free. Twenty hind limbs from skeletally mature Saanen breed goats were used in this study, ten each in IFS and press-fit groups. After ACL reconstruction the specimens were dissected, leaving a femur-ACL graft-tibia complex (FATC) for uniaxial tensile testing. The tests included a series of three cyclic creep tests (C1-C3) for the evaluation of residual elongation followed by a tensile load to failure test to obtain linear stiffness and ultimate load of the FATCs. Four of ten specimens failed during the cyclic creep test for the press-fit group, compared to one for the IFS group. For the remaining specimens residual elongation following three cyclic creep tests (C1-C3) was 1.7+/-0.5 mm in the press-fit group compared to 1.3+/-0.6 mm in the IFS group, and there was no statistical significant difference between the two fixations. In the load to failure test there was also no statistical significant difference in linear stiffness between the two fixations. However, the ultimate load for the press-fit group (215+/-75 N) was significantly lower than that for the IFS group (328+/-103 N). These results provide the basis for future studies involving the time course of healing of these two procedures using the goat model.

Prevention of anterior cruciate ligament injuries in female team handball players: a prospective intervention study over three seasons

OBJECTIVE

To assess the effect of a neuromuscular training program on the incidence of anterior cruciate ligament injuries in female team handball players.

DESIGN

Prospective intervention study.

SETTING

Female team handball: Division I-III in Norway.

PARTICIPANTS

Players from the three top divisions: control season (1998-1999), 60 teams (942 players); first intervention season (1999-2000), 58 teams (855 players); second intervention season (2000-2001), 52 teams (850 players).

INTERVENTION

A five-phase program (duration, 15 min) with three different balance exercises focusing on neuromuscular control and planting/landing skills was developed and introduced to the players in the autumn of 1999 and revised before the start of the season in 2000. The teams were instructed in the program and supplied with an instructional video, poster, six balance mats, and six wobble boards. Additionally, a physical therapist was attached to each team to follow up with the intervention program during the second intervention period.

MAIN OUTCOME MEASURES

The number of anterior cruciate ligament injuries during the three seasons and compliance with the program.

RESULTS

There were 29 anterior cruciate ligament injuries during the control season, 23 injuries during the first intervention season (OR, 0.87; CI, 0.50-1.52; p = 0.62), and 17 injuries during the second intervention season (OR, 0.64; CI, 0.35-1.18; p = 0.15). In the elite division, there were 13 injuries during the control season, six injuries during the first intervention season (OR, 0.51; CI, 0.19-1.35; p = 0.17), and five injuries in the second intervention season (OR, 0.37; CI, 0.13-1.05; p = 0.06). For the entire cohort, there was no difference in injury rates during the second intervention season between those who complied and those who did not comply (OR, 0.52; CI, 0.15-1.82; p = 0.31). In the elite division, the risk of injury was reduced among those who completed the anterior cruciate ligament injury prevention program (OR, 0.06; CI, 0.01-0.54; p = 0.01) compared with those who did not.

CONCLUSIONS

This study shows that it is possible to prevent anterior cruciate ligament injuries with specific neuromuscular training.

Arthroscopic surgery in the posterior compartment of the knee: Suture fixation of anterior and posterior cruciate ligament avulsions

Anterior and posterior cruciate ligament avulsion injuries in the posterior compartment of the knee are most commonly dealt with using open approaches. We report an arthroscopic method of treatment using sutures, without the need of any metal implants, that can be safely used in patients with open physes and without the need of a 70 degrees arthroscope.

EMG power spectra of intercollegiate athletes and anterior cruciate ligament injury risk in females

PURPOSE

Females have a disproportionately high incidence of anterior cruciate ligament (ACL) injuries compared with males in analogous sports. Although the pathogenesis of this higher frequency has not been elucidated, gender differences in neuromuscular control of the knee may play an important role. This study evaluates EMG power spectra of the quadriceps and hamstring muscles during dynamic, fatiguing exercise to examine differences between male and female intercollegiate athletes.

METHODS

Fifty-one collegiate basketball and soccer players (25 female, 26 male) were studied. Maximum voluntary contraction (MVC) was determined for knee flexion and extension. Three consecutive 2-min bouts of isokinetic knee flexion and extension exercise were performed at 40% MVC. EMG activity in the biceps femoris and vastus medialis obliquus was recorded using bipolar surface electrodes.

RESULTS

MVC normalized to body weight was significantly greater in males than in females for the quadriceps (P< 0.01). Quadriceps coactivation ratios were significantly higher in females than in males during knee flexion exercises (P< 0.01).

CONCLUSIONS

This study demonstrates differences in the EMG power spectra for females when compared with a matched group of males. Increased quadriceps coactivation in females may increase anterior tibial loads under dynamic conditions, thus placing the ACL at higher risk for injury in the female athlete.

The relationship between knee strength and functional stability before and after anterior cruciate ligament reconstruction

Functional stability of the knee is dependent on an intact ligamentous system and the timely and efficient contraction of supporting musculature. The aim of this study was to assess the relationship between muscle strength and functional stability in 31 patients pre- and post-operatively, following a unilateral anterior cruciate ligament rupture. All subjects underwent reconstructive surgery using semitendonosis and gracilis tendons. Isokinetic strength assessment of quadriceps and hamstring muscles was performed at a rate of movement of 60 degrees /s and 120 degrees /s. Functional stability was determined by performance during five functional stability tests that included the shuttle run, side step, carioca, single and triple hop tests. Pearson's correlation coefficient statistics were applied to pre-operative and post-operative data respectively. These analyses demonstrated a significant positive correlation between quadriceps strength indices at both testing speeds and the two hop tests pre-operatively (p's<0.007) and between quadriceps strength indices at both speeds and all five functional tests post-operatively (p's<0.01). Assessed using Steiger's formula, there was a significant increase in the correlation between quadriceps strength indices and three functional tests post-operatively compared to pre-operatively (p<0.05). No significant correlation between hamstring strength indices and functional scores existed pre- or post-operatively. This study has shown a significant correlation exists between quadriceps strength indices and functional stability both before and after surgery, this relationship does not reach significance between hamstring strength indices and functional stability.

Intraarticular inflammatory cytokines in acute anterior cruciate ligament injured knee

To understand the dynamics of the intraarticular acute inflammatory phase of an anterior cruciate ligament (ACL) injured knee, we analyzed the level of inflammatory cytokines (TNF-alpha, IL-1beta, IL-6, IL-8, IL-1ra, and IL-10) in joint fluid samples aspirated from 34 knees following an acute ACL injury. The samples were divided into the following five groups according to the duration from injury to aspiration: within 24 h (n=5), 2-3 days (n=14), 4-6 days (n=5), 7-9 days (n=5), 10-14 days (n=4), and 15-21 days (n=3). For comparison, 7 samples were also aspirated from 4 patients with osteoarthritis and 3 with postmenisectomy hydrops (chronic arthritis group). The highest levels of inflammatory cytokines were detected in the ACL-injury group within 24 h of the injury, and the levels decreased thereafter. While there were several patterns of decrease, nearly all of the inflammatory cytokines decreased to the level of that in the chronic arthritis group within 1 week. These dynamics are similar to those reported for inflammatory cytokines in wound fluid during wound healing, and suggest that the intraarticular healing process also progresses in ACL injured knees.

Intra-articular migration of femoral interference screw: Open or arthroscopic removal

Migration of the femoral interference screw in to the knee joint following anterior cruciate reconstruction is a rare complication. A migrated interference screw usually requires removal as it often results in mechanical symptoms. Formal arthrotomy may be required to remove a dislodged screw lying in the femoral notch because arthroscopic removal can be difficult or not possible in the presence of an intact integrated anterior cruciate ligament graft or scarring in the notch. When attempting arthroscopic removal in a similar situation, one should foresee the possibility of a formal arthrotomy and this should be discussed with the patient and consent obtained preoperatively.

Central third bone-patellar tendon-bone arthroscopic anterior cruciate ligament reconstruction: a 4-year follow-up

This prospective study reports the 4-year follow-up results of 56 patients (44 males and 12 females) who underwent arthroscopic reconstruction of the anterior cruciate ligament (ACL) using a central third bone-patellar tendon-bone free autologous graft and assesses the mid-term effectiveness of this technique. Mean patient age was 30.2 years (range: 17-44 years). Sports injuries were the primary cause of ACL deficiency in 93% of patients. All knees had an isolated ACL tear, and 31 had associated meniscal or chondral lesions. Patients in the acute phase did not undergo surgery for 3-4 weeks. In patients with subacute and chronic ACL ruptures, the mean interval between injury and surgery was 62 weeks (range: 8-104 weeks). According to the International Knee Documentation Committee grading system, 53 (95%) knees were considered normal or nearly normal postoperatively. Improvement by at least 1 grade was noted in 12 knees, 30 knees had an improvement of at least 2 grades, 12 knees had a 3-grade improvement, and 1 had a grade that remained unchanged. One knee deteriorated from a grade C to a grade D, which was attributed to graft lysis 1 year postoperatively. For best results, subacute reconstruction between 3 and 5 weeks postinjury is recommended.