A historical perspective of PCL bracing

Purpose

Currently there are many functional knee braces but very few designed to treat the posterior cruciate ligament (PCL). No PCL braces have been biomechanically validated to demonstrate that they provide stability with proper force distribution to the PCL-deficient knee. The purpose of this review was to evaluate the history and current state of PCL bracing and to identify areas where further progress is required to improve patient outcomes and treatment options.

Methods

A PubMed search was conducted with the terms “posterior cruciate ligament”, “rehabilitation”, “history”, “knee”, and “brace”, and the relevant articles from 1967 to 2011 were analysed. A review of the current available PCL knee bracing options was performed.

Results

Little evidence exists from the eight relevant articles to support the biomechanical efficacy of nonoperative and postoperative PCL bracing protocols. Clinical outcomes reported improvements in reducing PCL laxity with anterior directed forces to the tibia during healing following PCL tears. Biomechanics research demonstrates that during knee flexion, the PCL experiences variable tensile forces. One knee brace has been specifically designed and clinically validated to improve stability in PCL-deficient knees during rehabilitation. While available PCL braces demonstrate beneficial patient outcomes, they lack evidence validating their biomechanical effectiveness.

Conclusions

There is limited information evaluating the specific effectiveness of PCL knee braces. A properly designed PCL brace should apply correct anatomic joint forces that vary with the knee flexion angle and also provide adjustability to satisfy the demands of various activities. No braces are currently available with biomechanical evidence that satisfies these requirements.

Level of evidence

IV.     

Effect of genu recurvatum on the anterior cruciate ligament-deficient knee during gait

Purpose

This study aimed to investigate the effects of genu recurvatum, which is considered to carry a high risk for anterior cruciate ligament (ACL) injury, on healthy and post-ACL injury gait and lower extremity muscle strength.

Methods

Subjects were 36 patients with ACL-deficient knee and 40 healthy controls without pain or restricted range of motion of the lower extremity during gait. The knee joints of all subjects were examined; those with over 10° hyperextension of both knees were defined as exhibiting genu recurvatum. On this basis, the subjects were further subdivided into two groups: with or without genu recurvatum. A three-dimensional motion analysis system and force plates were used for gait analysis. Isokinetic dynamometers were used to measure knee muscle strength.

Results

There were no differences in joint angles, joint moments, or components of ground reaction force during gait or in knee strength for the healthy control subjects with and without genu recurvatum. ACL-deficient subjects without genu recurvatum showed a decrease in knee angles during the stance phase and a decrease in extension moments during the early stance phase compared with ACL-deficient subjects with genu recurvatum and controls. In contrast, neither knee angles nor extension moments during the stance phase differed significantly between ACL-deficient subjects with genu recurvatum and controls.

Conclusions

This study provides clinically relevant information regarding the effects of genu recurvatum on gait parameters. The results suggest that in ACL injuries, the presence of genu recurvatum alters gait pattern. Consideration of the presence of genu recurvatum would be useful during rehabilitation following ACL injuries or ACL reconstruction.

Level of evidence

II. Prospective comparative study.     

Relationship of native tibial plateau anatomy with stability testing in the anterior cruciate ligament-deficient knee

Purpose

Recent attention has been drawn to tibial plateau slope and depth with relation to both risk of anterior cruciate ligament (ACL) tear and kinematics in the cruciate-deficient knee. The purpose was to evaluate the relationship between native proximal tibial anatomy and knee kinematics in the anterior cruciate-deficient knee.

Methods

Twenty-two cadaveric knees underwent CT scanning to measure proximal tibia anatomy. Translation was measured during Lachman and mechanized pivot-shift tests on the intact knee and then after resection of the ACL. Pearson’s correlation was calculated to assess the relationship between tibial translation of the ACL-deficient knee and tibial plateau anatomic parameters.

Results

No significant correlation was found between ACL-deficient kinematic testing and tibial slope or depth (n.s.). Lateral compartment translation on Lachman and pivot-shift testing correlated with lateral compartment AP length (P?=?0.007 and P?=?0.033, respectively). The ratio of lateral AP length to medial AP length correlated with lateral compartment translation during the pivot shift (P?=?0.002).

Conclusion

There was a poor correlation between native tibial slope and kinematic testing. There were, however, increases in translation during pivot-shift and Lachman testing with increased AP length of the lateral compartment. In addition, the finding of increased pivot-shift magnitude when the lateral compartment was relatively wide in the AP plane compared to the medial compartment suggests that patients with a “dominant” lateral compartment may be prone to a greater magnitude of instability after ACL injury.     

Sectioning the anterolateral ligament did not increase tibiofemoral translation or rotation in an ACL-deficient cadaveric model

Purpose

The anterolateral ligament (ALL) has been proposed as a possible extra-articular stabiliser of the knee. Injury to the ALL may result in residual instability following surgical reconstruction of a ruptured anterior cruciate ligament (ACL). Few studies have evaluated the biomechanical role of the ALL. The purpose of this study was to investigate whether sectioning the ALL would have an influence on tibiofemoral translation or rotation during the anterior drawer, Lachman, pivot shift, external rotation, and internal rotation tests in an ACL-deficient knee.

Methods

Only whole-body specimens having an ALL were included in this study. Lachman, anterior drawer, external rotation, and internal rotation tests were performed manually. Pivot shift test was done using a mechanised pivot shifter. The amount of tibiofemoral translation and rotation was recorded by a navigation system. Each specimen was tested in its native state, after sectioning the ACL, and after combined sectioning of the ACL and the ALL.

Results

In six out of 14 cadaveric knees, an ALL could be identified. The ACL-deficient knee had significantly more tibiofemoral translation and rotation compared to the native knee (P < 0.05). However, no changes in the magnitudes of translation or rotation were seen after subsequent sectioning of the ALL compared to the ACL-deficient knee (P > 0.05).

Conclusion

Adding an ALL lesion in an ACL-deficient knee did not increase tibiofemoral instability in this cadaveric model. It remains unclear whether injury to the ALL would result in substantial knee instability in the setting of ACL injury in vivo. Further research is warranted to fully elucidate the role of the ALL during knee kinematics and to determine in which scenarios ALL repair would be warranted. Understanding the function of the ALL may improve the current treatment strategies for ACL ruptures.

     

Brace or no-brace after ACL graft? Four-year results of a prospective clinical trial

Purpose

A controversial discussion is held on using stabilizing knee braces after anterior cruciate ligament (ACL) surgery. The current study investigated the influence of a stabilizing knee brace on results after ACL reconstruction using patellar tendon autografts.

Methods

A prospective randomized study was started including 64 patients divided into two equal groups and treated with or without a stabilizing knee brace for 6 weeks post-operatively. A follow-up examination 4 years after operation comprised IKDC 2000, KT1000 measurement, a visual analogue pain scale (VAS; scores 0–10) and radiographic evaluation. The t test for independent and paired samples and the Pearson’s Chi-square test were used for statistical analysis (p < 0.05). The primary endpoint was the difference in IKDC classification.

Results

Eighty-one per cent of the patients were examined 4 years post-operatively. IKDC 2000 subjective (brace group 90.5 ± 8.9, braceless group 93.2 ± 6.1) and objective results (brace A 30 %, B 56 %, C 16 %; braceless A 32 %, B 48 %, C 20 %) and instrumental measurement of anteroposterior laxity with KT1000 (brace 0.6 ± 2.4 mm, braceless 1.8 ± 3.4 mm) showed no significant differences. VAS pain results were significantly better in the braceless group at 1.0 ± 1.2 versus 1.9 ± 1.4 under sports activity or heavy physical work (p = 0.015). There were no radiographic differences concerning osteoarthritic findings and tunnel widening between the groups.

Conclusion

Post-operative treatment with a stabilizing knee brace after ACL replacement showed no advantage over treatment without a brace at 4-year follow-up. The use of a knee-stabilizing brace after isolated ACL reconstruction with autologous patellar tendon graft is not recommended.

Level of evidence

II.     

The concept of individualized anatomic anterior cruciate ligament (ACL) reconstruction

Purpose

To describe the concept of individualized anatomic anterior cruciate ligament (ACL) reconstruction.

Methods

The PubMed/Medline database was searched using keywords pertaining to ACL reconstruction. Relevant articles were reviewed in order to summarize important concepts of individualized surgery in ACL reconstruction. Surgical experiences with case examples are also highlighted.

Results

Individualized ACL surgery allows for the customization of surgery to each individual patient. Accounting for graft selection and other characteristics such as anatomy, lifestyle and activity preferences may provide the patient with the best potential for a successful outcome. The surgeon should be comfortable with a variety of graft harvests and surgical techniques when practicing individualized surgery.

Conclusion

Individualized anatomic ACL reconstruction is founded on the objective evaluation of functional anatomy and individual characteristics, thereby restoring the ACL as closely as possible to the native anatomy and function. The adoption and subsequent use of individualized surgery may facilitate improved clinical as well as objective outcomes, particularly in the long term.

Level of evidence

V.     

One-stage bilateral anterior cruciate ligament reconstruction

Purpose

The ideal treatment for patients presenting with bilateral anterior cruciate ligament (ACL) deficiency remains controversial. The purpose was to evaluate cost and functional results after one-stage bilateral ACL reconstruction using either hamstring or patella tendon autograft.

Methods

This prospective comparative study was compared the mid-term outcome of 7 patients (14 knees) who had one-stage bilateral ACL reconstruction with that of a matched group of patients who had unilateral reconstruction (21 patients).

Results

The median length of hospital stay was 4 (3–5) nights for the bilateral group and 2 (1–4) nights for the control group. The duration of rehabilitation process in patients from control group with unilateral ACL reconstruction was one week shorter (9 vs 8 weeks). In the bilateral group, the median Lysholm score was 96 (85–100), and in the control group, the median score was 93 (81–100). The median time to return to full-time work and to full sports was 9 weeks and 7 months for the one-stage group and 8 weeks and 6 months for the unilateral group. Six patients (86 %) in the bilateral group and 17 patients (81 %) in the control group were still performing at their pre-injury level of activity. National Health Institution saved 2925 EUR when we performed one-stage bilateral reconstruction instead of two-stage ACL reconstruction.

Conclusions

Mid-term clinical results suggested that one-stage bilateral ACL reconstruction using either hamstring or patella tendon autograft is clinically effective. For patients presenting bilateral ACL-deficient knees, one-stage bilateral ACL reconstruction is reproducible, cost effective and does not compromise functional results.

Level of evidence

II.     

The role of the tibial slope in sustaining and treating anterior cruciate ligament injuries

Purpose

A steep tibial slope may contribute to anterior cruciate ligament (ACL)-injuries, a higher degree of instability in the case of ACL insufficiency, and recurrent instability after ACL reconstruction. A better understanding of the significance of the tibial slope could improve the development of ACL injury screening and prevention programmes, might serve as a basis for individually adapted rehabilitation programmes after ACL reconstruction and could clarify the role of slope-decreasing osteotomies in the treatment of ACL insufficiency. This article summarizes and discusses the current published literature on these topics.

Methods

A comprehensive review of the MEDLINE database was carried out to identify relevant articles using multiple different keywords (e.g. ‘tibial slope’, ‘anterior cruciate ligament’, ‘osteotomy’, and ‘knee instability’). The reference lists of the reviewed articles were searched for additional relevant articles.

Results

In cadaveric studies, an artificially increased tibial slope produced an anterior shift of the tibia relative to the femur. While mathematical models additionally demonstrated increased strain in the ACL, cadaveric studies have not confirmed these findings. There is some evidence that a steep tibial slope represents a risk factor for non-contact ACL injuries. MRI-based studies indicate that a steep slope of the lateral tibial plateau might specifically be responsible for this injury mechanism. The influence of the tibial slope on outcomes after ACL reconstruction and the role of slope-decreasing osteotomies in the treatment of ACL insufficiency remain unclear.

Conclusion

The role of the tibial slope in sustaining and treating ACL injuries is not well understood. Characterizing the tibial plateau surface with a single slope measurement represents an insufficient approximation of its three-dimensionality, and the biomechanical impact of the tibial slope likely is more complex than previously appreciated.

Level of evidence

IV.     

Restoring tibiofemoral alignment during ACL reconstruction results in better knee biomechanics

Purpose

Anterior cruciate ligament (ACL) reconstruction (ACLR) aims to restore normal knee joint function, stability and biomechanics and in the long term avoid joint degeneration. The purpose of this study is to present the anatomic single bundle (SB) ACLR that emphasizes intraoperative correction of tibiofemoral subluxation that occurs after ACL injury. It was hypothesized that this technique leads to optimal outcomes and better restoration of pathological tibiofemoral joint movement that results from ACL deficiency (ACLD).

Methods

Thirteen men with unilateral ACLD were prospectively evaluated before and at a mean follow-up of 14.9 (SD?=?1.8) months after anatomic SB ACLR with bone patellar tendon bone autograft. The anatomic ACLR replicated the native ACL attachment site anatomy and graft orientation. Emphasis was placed on intraoperative correction of tibiofemoral subluxation by reducing anterior tibial translation (ATT) and internal tibial rotation. Function was measured with IKDC, Lysholm and the Tegner activity scale, ATT was measured with the KT-1000 arthrometer and tibial rotation (TR) kinematics were measured with 3Dmotion analysis during a high-demand pivoting task.

Results

The results showed significantly higher TR of the ACL-deficient knee when compared to the intact knee prior to surgery (12.2° ± 3.7° and 10.7° ± 2.6° respectively, P?=?0.014). Postoperatively, the ACLR knee showed significantly lower TR as compared to the ACL-deficient knee (9.6°±3.1°, P?=?0.001) but no difference as compared to the control knee (n.s.). All functional scores were significantly improved and ATT was restored within normal values (P?<?0.001).

Conclusions

Intraoperative correction of tibiofemoral subluxation that results after ACL injury is an important step during anatomic SB ACLR. The intraoperative correction of tibiofemoral subluxation along with the replication of native ACL anatomy results in restoration of rotational kinematics of ACLD patients to normal levels that are comparable to the control knee. These results indicate that the reestablishment of tibiofemoral alignment during ACLR may be an important step that facilitates normal knee kinematics postoperatively.

Level of evidence

Level II, prospective cohort study.

     

Prevention of anterior cruciate ligament injuries in sports—Part I: Systematic review of risk factors in male athletes

Purpose

The purpose of this study was to report a comprehensive literature review on the risk factors for anterior cruciate ligament (ACL) injuries in male athletes.

Methods

All abstracts were read and articles of potential interest were reviewed in detail to determine on inclusion status for systematic review. Information regarding risk factors for ACL injuries in male athletes was extracted from all included studies in systematic fashion and classified as environmental, anatomical, hormonal, neuromuscular, or biomechanical. Data extraction involved general characteristics of the included studies (type of study, characteristics of the sample, type of sport), methodological aspects (for quality assessment), and the principal results for each type of risk factor.

Results

The principal findings of this systematic review related to the risk factors for ACL injury in male athletes are: (1) most of the evidence is related to environmental and anatomical risk factors; (2) dry weather conditions may increase the risk of non-contact ACL injuries in male athletes; (3) artificial turf may increase the risk of non-contact ACL injuries in male athletes; (4) higher posterior tibial slope of the lateral tibial plateau may increase the risk of non-contact ACL injuries in male athletes.

Conclusion

Anterior cruciate ligament injury in male athletes likely has a multi-factorial aetiology. There is a lack of evidence regarding neuromuscular and biomechanical risk factors for ACL injury in male athletes. Future research in male populations is warranted to provide adequate prevention strategies aimed to decrease the risk of this serious injury in these populations.

Level of evidence

Systematic review on level I–IV studies, Level IV.     

A comparison of dynamic rotational knee instability between anatomic single-bundle and over-the-top anterior cruciate ligament reconstruction using triaxial accelerometry

Purpose

Recently, single-bundle (SB) anterior cruciate ligament (ACL) reconstruction has been advanced by the anatomic concept, but the biomechanical outcome of the anatomic method has not been fully investigated, especially for rotational instability. Anatomic SB and the single over-the-top procedures are the treatment of choice for primary cases and revision or skeletally immature cases, respectively. The purpose of this study was to investigate the dynamic rotational instability of anatomic SB and over-the-top reconstruction during a pivot shift test using triaxial accelerometry.

Methods

Eight fresh frozen human cadaveric knees were used in this study. Rotational instability measurement was conducted during a pivot shift test by the use of a triaxial accelerometer attached to the tibia. The tests were performed in the ACL-intact, ACL-deficient and ACL-reconstructed knees with two different procedures (anatomic SB and over-the-top). The acceleration in three directions and the magnitude of acceleration were measured to evaluate rotational instability and compare between four different knee states.

Results

The overall magnitude of acceleration was significantly different (P < 0.01) between the ACL-intact knees and the ACL-deficient knees. Both anatomic SB and over-the-top ACL reconstruction significantly reduced the overall magnitude of acceleration compared to the ACL-deficient knees, but still had larger accelerations compared to the ACL-intact knees. There was no significant difference for the overall magnitude of acceleration between anatomic SB and over-the-top reconstruction procedure.

Conclusion

Over-the-top reconstruction provides comparable result to anatomic SB reconstruction in terms of controlling the dynamic rotational stability. Over-the-top reconstruction might be one of the options for revision cases and in skeletally immature patients.     

Lessons learned from the last 20 years of ACL-related in vivo-biomechanics research of the knee joint

Purpose

Technological advances in recent years have allowed the easy and accurate assessment of knee motion during athletic activities. Subsequently, thousands of studies have been published that greatly improved our understanding of the aetiology, surgical reconstruction techniques and prevention of anterior cruciate ligament (ACL) injuries. The purpose of this review is to summarize the evidence from biomechanical studies on ACL-related research.

Methods

High-impact articles that enhanced understanding of ACL injury aetiology, rehabilitation, prevention and adaptations after reconstruction were selected.

Results

The importance of restoring internal tibial rotation after ACL reconstruction has emerged in several studies. Criteria-based, individualized rehabilitation protocols have replaced the traditional time-based protocols. Excessive knee valgus, poor trunk control, excessive quadriceps forces and leg asymmetries have been identified as potential high risk biomechanical factors for ACL tear. Injury prevention programmes have emerged as low cost and effective means of preventing ACL injuries, particularly in female athletes.

Conclusion

As a result of biomechanical research, clinicians have a better understanding of ACL injury aetiology, prevention and rehabilitation. Athletes exhibiting neuromuscular deficits predisposing them to ACL injury can be identified and enrolled into prevention programmes. Clinicians should assess ACL-reconstructed patients for excessive internal tibial rotation that may lead to poor outcomes.

Level of evidence

III.     

Prevention and rehabilitation of paediatric anterior cruciate ligament injuries

Purpose

To review the current knowledge on anterior cruciate ligament (ACL) injury prevention and ACL rehabilitation in individuals who have not yet reached musculoskeletal maturity.

Methods

This is a narrative review based on a targeted and systematic literature search for paediatric ACL injury risk factors, injury prevention and rehabilitation.

Results

The search strategies resulted in 119 hits on risk factor studies, 57 hits on prevention and 37 hits on rehabilitation. Modifiable risk factors for ACL injury are largely unknown in the paediatric population. ACL injury prevention using neuromuscular training is highly successful in the adolescent population, and existing injury prevention programmes are cost-effective. The efficacy of ACL injury prevention programmes in children is, however, investigated to a markedly lesser degree. Paediatric ACL injury rehabilitation is poorly described, although supervised active rehabilitation progressed through phases with functional milestones is generally encouraged.

Conclusion

Although limited, current evidence supports implementation of injury prevention programmes in female football players from the age of 12. Supervised active rehabilitation where progression is guided by functional milestones is also advocated. Future identification of modifiable risk factors is needed to design prevention programmes for younger children. There is a need for international multicentre studies on treatment algorithms and rehabilitation to increase knowledge on the short- and long-term outcomes following existing algorithms.

Study design

Narrative review, level III.

     

Strategies for revision surgery after primary double-bundle anterior cruciate ligament (ACL) reconstruction

Purpose

The purpose of this article was to discuss pre- and intra-operative considerations as well as surgical strategies for different femoral and tibial tunnel scenarios in revision surgery following primary double-bundle anterior cruciate ligament (ACL) reconstruction.

Methods

Based on the current literature of ACL revision surgery and surgical experience, an algorithm for revision surgery after primary double-bundle ACL reconstruction was created.

Results

A guideline and flowchart were created using a case-based approached for revision surgery after primary double-bundle ACL reconstruction.

Conclusion

Revision surgery after primary double-bundle ACL reconstruction can be a challenging procedure that requires flexibility and a repertoire of surgical techniques. The combination of pre-operative planning with 3D-CT reconstruction, in addition to careful intra-operative assessment, and the use of this flowchart can simplify the ACL revision procedure.

Level of evidence

V.     

Is valgus unloader bracing effective in normally aligned individuals: implications for post-surgical protocols following cartilage restoration procedures

Purpose

Utilizing valgus unloader braces to reduce medial compartment loading in patients undergoing cartilage restoration procedures may be an alternative to non-weightbearing post-operative protocols in these patients. It was hypothesized that valgus unloader braces will reduce knee adduction moment during the stance phase in healthy subjects with normal knee alignment.

Methods

Gait analysis was performed on twelve adult subjects with normal knee alignment and no history of knee pathology. Subjects were fitted with an off-the-shelf adjustable valgus unloader brace and tested under five conditions: one with no brace and four with increasing valgus force applied by the brace. Frontal and sagittal plane knee angles and external moments were calculated during stance via inverse dynamics. Analyses of variance were used to assess the effect of the brace conditions on frontal and sagittal plane joint angles and moments.

Results

With increasing tension in the brace, peak frontal plane knee angle during stance shifted from 1.6° ± 4.2° varus without the brace to 4.1° ± 3.6° valgus with maximum brace tension (P = 0.02 compared with the no brace condition). Peak knee adduction moment and knee adduction impulse decreased with increasing brace tension (main effect of brace, P < 0.001). Gait velocity and sagittal plane knee biomechanics were minimally affected.

Conclusion

The use of these braces following a cartilage restoration procedure may provide adequate protection of the repair site without limiting the patient’s mobility.

Level of evidence

Therapeutic prospective comparative study, Level II.     

Evaluating rotational kinematics of the knee in ACL-ruptured and healthy patients using 3.0 Tesla magnetic resonance imaging

Purpose

Rotational knee laxity is an important measure in restoring knee stability following anterior cruciate ligament (ACL) injury, but is difficult to quantify with current clinical tools. The hypothesis of the study is that there is greater tibial rotation (TR) in women than men, and also in ACL-deficient than healthy knees.

Methods

Sixteen healthy (8 men, 26.8?±?6.4?years; 8 women, 26.9?±?3.8?years) and ten ACL-deficient (5 men, 33.6?±?10.5?years; 5 women, 36.3?±?10.7?years) subjects received bilateral knee MRI in 15° of flexion using a custom device to apply a constant axial compressive load (44?N). A rotational torque (3.35?Nm) was sequentially applied to obtain images at internal and external rotation positions. T ₂-weighted images were acquired in internal and external rotation. Images were segmented and TR was calculated. To assess reproducibility, six knees were scanned twice on separate days. Group comparisons were made with unpaired t tests, while intrasubject comparisons were made using paired t tests.

Results

Healthy women demonstrated greater TR than men (13.6°?±?4.7° vs. 8.3°?±?3.6°; P?=?0.001). Male ACL-deficient knees showed greater TR than the contralateral knee (15.7°?±?6.9° vs. 7.7°?±?5.6°; P?=?0.003), and compared to male controls (P?=?0.002). ACL-deficient women showed greater TR compared to their contralateral leg (15.1°?±?2.3° vs. 10.0°?±?4.3°; P?=?0.01). The intraclass correlation coefficient of the TR measurement was 0.913, and the SEM?=?1.1°.

Conclusions

Kinematic MRI is a reproducible method to quantify total knee rotation. Women have more rotational laxity than men, particularly in the external rotation position. ACL rupture leads to increased rotational laxity of the knee.

Level of evidence

Retrospective case–control series, Level III.     

Change of signal intensity in the displaced medial meniscus after its reduction on MRI

Purpose

To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury.

Methods

Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1–2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients.

Results

In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients.

Conclusions

A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI.

Level of evidence

Diagnostic study, Level III.     

Bracing improves clinical outcomes but does not affect the medial knee joint space in osteoarthritic patients during gait

Purpose

Osteoarthritis (OA) of the knee is commonly treated through the use of medial compartment unloading braces which have been shown to improve clinical symptoms. The objective of this study was to assess the effects of a medial compartment unloading brace on biomechanical measurements and clinical outcomes. We hypothesized that brace usage would lead to increased medial joint space and improved clinical outcomes.

Methods

Ten patients with medial compartment OA were prescribed a medial compartment unloading brace and underwent dynamic biplane radiograph imaging while walking with and without the brace. The Western Ontario and McMaster University Osteoarthritis (WOMAC) Index was used to assess pain before brace wear and at the time of testing. The 3D position and orientation of the femur and tibia were determined using a model-based tracking technique.

Results

Patients saw an average improvement of 33 % in their WOMAC scores (p = 0.01). This study failed to detect any statistically significant changes in the functional joint space, knee kinematics, or contact centre location between the braced and unbraced condition (n.s.).

Conclusion

The data from this study, using a highly accurate (±0.6 mm and ±0.6°) 3D radiograph analysis of dynamic tibiofemoral motion, suggest that the brace is ineffective at increasing joint space. However, it was shown to be effective in improving clinical outcome and therefore should continue to be prescribed to patients even though the mechanism of its effectiveness remains unknown.

Level of evidence

IV.     

Posterior cruciate ligament tears: functional and postoperative rehabilitation

Purpose

Historically, the results of posterior cruciate ligament (PCL) reconstructions are not as favourable as anterior cruciate ligament (ACL) reconstructions, and it is well recognized that nonoperative treatment and postoperative rehabilitation for PCL injuries must be altered compared to those for ACL injuries. The purpose of this article was to review current peer-reviewed PCL rehabilitation programmes and to recommend a nonoperative and postoperative programme based on basic science and published outcomes studies.

Methods

To discover the current practices being used to rehabilitate PCL injuries, we conducted a search of PubMed with the terms “posterior cruciate ligament” and “rehabilitation” from 1983 to 2011. All articles within the reference lists of these articles were also examined to determine their rehabilitation programmes.

Results

A review of peer-reviewed PCL rehabilitation protocols revealed that the treatment of PCL injuries depends on the timing and degree of the injury. Rehabilitation should focus on progressive weight bearing, preventing posterior tibial subluxation and strengthening of the quadriceps muscles. General principles of proper PCL rehabilitation, whether nonoperative or postoperative, should include early immobilization (when necessary), prone passive range of motion to prevent placing undue stress on grafts or healing tissue, and progression of rehabilitation based on biomechanical, clinical, and basic science research.

Conclusions

An optimal set of guidelines for the nonoperative or postoperative management of PCL injuries has not yet been defined or agreed upon. Based on the current review study, suggested guidelines are proposed.

Level of evidence

IV.     

Variability in knee laxity in anterior cruciate ligament deficiency using a mechanized model

Purpose

To establish normative values for the magnitude of anterior tibial translation (ATT) in the Lachman and pivot shift tests in the intact and anterior cruciate ligament (ACL)-deficient states, and to explore whether a correlation in ATT magnitude exists between the Lachman and pivot shift tests.

Methods

Twenty-six fresh frozen cadaveric hip-to-toe specimens were used. Mechanized testing was performed to simulate both a Lachman and pivot shift test with the ACL intact. Tests were repeated after sectioning the ACL. ATT was recorded using a computer navigation system. Difference in ATT after sectioning was calculated for each specimen.

Results

For the Lachman, mean lateral compartment ATT in the intact knee was 5.3 mm (SD = 2.8 mm). After sectioning the ACL, translation increased to 11.4 mm (SD = 3.9 mm; P < 0.05). For the mechanized pivot shift, mean lateral compartment ATT in the intact knee was ?0.2 mm (SD = 2.6 mm). After sectioning the ACL, translation increased to 8.2 mm (SD = 3.1 mm; P < 0.05). No correlation in the magnitude of ATT was found between the intact and ACL-deficient knees for either the Lachman or pivot shift tests, or between both tests (Cronbach’s α < 0.7).

Conclusions

No correlation was found between the Lachman and pivot shift test in both the intact and ACL-deficient knee. This suggests that the Lachman cannot be used as a surrogate for the pivot shift as the magnitude of the Lachman did not predict the magnitude of the pivot shift.