Impaired voluntary quadriceps force control following anterior cruciate ligament reconstruction: relationship with knee function

Purpose

Impairments in quadriceps force control and altered quadriceps and hamstring muscle activation strategies have been observed following anterior cruciate ligament reconstruction; however, the functional implications of these impairments are unclear. This study examined the cross-sectional associations between quadriceps force control, quadriceps activation, hamstring coactivation and clinically assessed knee function following anterior cruciate ligament reconstruction with a hamstring graft.

Methods

Sixty-six patients (18 ± 3 months following surgery) and 41 uninjured individuals participated. Quadriceps force control was assessed using an isometric knee extension task. Participants cyclically increased and decreased quadriceps force at slow speeds between 5 and 30 % maximum voluntary isometric contraction matching a moving target displayed on a screen. Quadriceps activation and hamstring coactivation were assessed concurrently using surface electromyography. Knee function was assessed with the Cincinnati Knee Rating Scale and three single-leg hop tests.

Results

The reconstructed group completed the task with 48 % greater root-mean-square error (RMSE), indicating significantly worse quadriceps force control (p < 0.001). In a multivariable model adjusted for sex, greater RMSE and greater lateral hamstring coactivation were significantly associated with worse knee function that is greater odds of scoring <85 % on one or more knee functional assessment.

Conclusions

Less-accurate quadriceps force output and greater hamstring coactivation are associated with worse knee joint function following anterior cruciate ligament reconstruction and may contribute to irregular knee joint loading and the onset or progression of knee osteoarthritis. Impairments in quadriceps force control and altered muscle activation strategies may be modifiable through neuromuscular training, and this is an area for future research.

Level of evidence

Case–control study, Level III.

     

Do ground reaction forces during unilateral and bilateral movements exhibit compensation strategies following ACL reconstruction?

Purpose

The aims of the study were (1) to evaluate the leg asymmetry assessed with ground reaction forces (GRFs) during unilateral and bilateral movements of different knee loads in anterior cruciate ligament (ACL) reconstructed patients and (2) to investigate differences in leg asymmetry depending on the International Knee Documentation Committee Subjective Form (IKDC) in order to identify potential compensation strategies.

Methods

The knee function of 50 ACL reconstructed (patella tendon) patients was examined at 31 ± 7 months after the surgery. GRFs were quantified during the sit-to-stand and stand-to-sit test, the step-up and step-down test, and the two- and one-leg vertical jump. Further, the IKDC score, the anterior–posterior knee laxity, and the concentric torque of the quadriceps and hamstring muscles were evaluated.

Results

Differences between the operated and non-operated leg were found in the knee laxity, the quadriceps torque, and GRFs. The patients with low IKDC scores demonstrated greater leg asymmetries in GRFs compared to the patients with high IKDC scores.

Conclusions

ACL reconstructed patients showed GRF asymmetries during unilateral and bilateral movements of different knee loads. Three compensation strategies were found in patients with low subjective knee function: (1) a reduced eccentric load, (2) an inter-limb compensation during bilateral movements, and (3) the avoidance of high vertical impact forces. These compensation strategies may be indicative of a protective adaptation to avoid excessive ACL strain. GRF measurements are practicable and efficient tools to identify individual compensation strategies during early rehabilitation.

     

No risk of arthrofibrosis after acute anterior cruciate ligament reconstruction

Purpose

To compare acute ACL reconstruction (ACLR) within 8 days of injury with delayed reconstruction after normalized range of motion (ROM), 6–10 weeks after injury. It was hypothesized that acute ACL reconstruction with modern techniques is safe and can be beneficial in terms of patient-reported outcomes and range of motion.

Methods

Sample size calculation indicated 64 patients would be required to find a 5° difference in ROM at 3 months. Seventy patients with high recreational activity level, Tegner level 6 or more, were randomized to acute (within 8 days) or delayed (6–10 weeks) ACLR between 2006 and 2013. During the first 3 months following surgery patients were contacted weekly by SMS and asked ‘How is your knee functioning?’, with answers given on a Visual-Analog Scale (0–10). ROM was assessed after 3 months by the rehab physiotherapist. Patient-reported outcomes, objective IKDC and manual stability measurements were collected by an independent physiotherapist not involved in the rehab at the 6-month follow-up.

Results

At 3-month follow-up, 91% of the patients were assessed with no significant differences in flexion, extension or total ROM demonstrated between groups. At the 6-month follow-up, the acute group had significantly less muscle atrophy of the thigh muscle compared to the contralateral leg. Furthermore, a significantly higher proportion of patients in the acute group passed or were close to passing the one leg hop test (47 versus 21%, p?=?0.009). No difference was found between the groups in the other clinical assessments. Additionally, no significant difference between the groups was found in terms of associated injuries.

Conclusion

Acute ACLR within 8 days of injury does not appear to adversely affect ROM or result in increased stiffness in the knee joint when compared to delayed surgery.

Level of evidence

II.

     

The evaluation of muscle recovery after anatomical single-bundle ACL reconstruction using a quadriceps autograft

Purpose

The purpose of this study was to reveal the degree of muscle recovery and report the clinical results of anatomical single-bundle ACL reconstruction using a quadriceps autograft.

Methods

Twenty subjects undergoing anatomical single-bundle ACL reconstruction using a quadriceps autograft were included in this study. A 5-mm-wide, 8-cm-long graft, involving the entire layer of the quadriceps tendon, was harvested without bone block. The average graft diameter was 8.1 ± 1.4 mm. An initial tension of 30 N was applied. The femoral tunnel was created from the far-medial portal. Each femoral and tibial tunnel was created close to the antero-medial bundle insertion site. For the evaluation of muscle recovery (quadriceps and hamstring), a handheld dynamometer was used. The evaluation of muscle recovery was performed pre-operatively, and at 3, 6, 9, and 12 months after surgery. Muscle recovery data were calculated as a percentage of leg strength in the non-operated leg. Anterior tibial translation (ATT), pivot shift test, and IKDC score were evaluated.

Results

The average quadriceps strength pre-operatively, and at 3, 6, 9, and 12 months after ACL reconstruction was 90.5 ± 19, 67.8 ± 21.4, 84 ± 17.5, and 85.1 ± 12.6 %, respectively. The average hamstring strength pre-operatively, and at 3, 6, 9, and 12 months after ACL reconstruction was 99.5 ± 13.7, 78.7 ± 11.4, 90.5 ± 19, and 96.7 ± 13.8 %, respectively. ATT pre-operatively and at 12 months after surgery was 5.4 ± 1.3 and 1.0 ± 0.8 mm, respectively. No subjects exhibited positive pivot shift after surgery. Within 6 months following surgery, quadriceps hypotrophy was observed in all subjects. However, the hypotrophy had recovered at 12 months following surgery. No subjects complained of donor site pain after surgery.

Conclusion

Anatomical single-bundle ACL reconstruction using a quadriceps autograft resulted in equivalent level of muscle recovery and knee stability when compared with previously reported ACL reconstruction using hamstrings tendon with no donor site complications.

Level of evidence

Case controlled study, Level III.

     

Quantitative magnetic resonance imaging (MRI) morphological analysis of knee cartilage in healthy and anterior cruciate ligament-injured knees

Purpose

To analyze the morphological change in the cartilage of the knee after anterior cruciate ligament (ACL) injury by comparing with that of the intact contralateral knee.

Methods

A total of 22 participants (12 male and 10 female patients) who had unilateral ACL injury underwent MRI scan of both the injured and intact contralateral knees. Sagittal plane images were segmented using a modeling software to determine cartilage volume and cartilage thickness in each part of the knee cartilage that were compared between the ACL-injured and the intact contralateral knees. Furthermore, the male and female patients’ data were analyzed in subgroups.

Results

The ACL-injured knees had statistically significant lower total knee cartilage volume than the intact contralateral knees (P = 0.0020), but had similar mean thickness of total knee cartilage (not significant: n.s.). In the male subgroup, there was no significant difference in cartilage volume and thickness between normal and ACL-injured knees. In the female subgroup, the ACL-injured knees demonstrated statistically significant difference in total knee cartilage volume (P = 0.0004) and thickness (P = 0.0024) compared with the normal knees. The percentage change in the cartilage thickness in women was significantly greater than that in men.

Conclusion

Cartilage volume was significantly smaller in the ACL-injured knees than in the contralateral intact knees in this cohort. Women tended to display greater cartilage volume and thickness change after ACL injury than men. These findings indicated that women might be more susceptible to cartilage alteration after ACL injuries.

Level of evidence

III.

     

Altered movement during single leg hop test after ACL reconstruction: implications to incorporate 2-D video movement analysis for hop tests

Purpose

There is a lack of objective factors which can be used in guiding the return to sport (RTS) decision after an anterior cruciate ligament reconstruction (ACLR). The purpose of the current study was to conduct qualitative analysis of the single leg hop (SLH) in patients after ACLR with a simple and clinical friendly method and to compare the possible difference in movement pattern between male and female patients.

Methods

Sixty-five patients performed the single leg hop (SLH) test at 6.8?±?1.0 months following isolated ACLR. Digital video camcorders recorded frontal and sagittal plane views of the patient performing the SLH. Knee flexion at initial contact (IC), peak knee flexion, knee flexion range of motion (RoM), and knee valgus RoM were calculated. In addition, limb symmetry index (LSI) scores were calculated.

Results

No differences were found in movement pattern between males and females. Movement analysis revealed that males had a decrease in knee flexion at IC (p?=?0.018), peak knee flexion (p?=?0.002), and knee flexion RoM (p?=?0.017) in the injured leg compared to the non-injured leg. Females demonstrated a decrease in peak knee flexion (p?=?0.011) and knee flexion RoM (p?=?0.023) in the injured leg compared to the non-injured leg. Average LSI scores were 92.4% for males and 94.5% for females.

Conclusions

Although LSI scores were >?90%, clinical relevant altered movement patterns were detected in the injured leg compared to the non-injured leg. Caution is warranted to solely rely on LSI scores to determine RTS readiness.

Clinical trial registry name and registration

The University of Groningen, ID 2012.362.

Level of evidence

III.

     

Proprioception after bicruciate-retaining total knee arthroplasty is comparable to unicompartmental knee arthroplasty

Purpose

Rising expectations in functional performance of total knee joints are inciting further improvement of knee arthroplasty implants. From a patient-centred view, bicruciate-retaining models provide a more natural feeling knee. However, there is no evidence of functional advantage for these implants. The aim of this study was to evaluate balance ability as a measure of proprioception in patients with a bicruciate-retaining total knee arthroplasty.

Methods

A prospective, controlled trial was conducted to compare balance ability in 60 patients after arthroplasty of the knee for osteoarthritis. We compared patients with a bicruciate-retaining knee arthroplasty (BCR group) to a control group of patients with a medial unicompartmental knee arthroplasty (UKA group) and another control group of patients with a posterior stabilized total knee arthroplasty (PS group). The patient population comprised 30 women (50.0 %) and 30 men in three cohorts of 20 each. The mean age was 62.1 ± 8.0 years (range 43–78). Patients were evaluated preoperatively and 9 months post-operatively. The evaluation included clinical, radiological, and balance testing—a single-leg stance with eyes closed compared to eyes open. The difference in area of sway between eyes closed and eyes open represents static balance ability after knee arthroplasty.

Results

Perioperative data showed that there was no intra-operative fracture of the intercondylar eminence. There was a decreased post-operative knee extension 9 months post-operative in the BCR group, which was not clinically relevant in any case. We recorded a lower difference in the area of sway between eyes closed and eyes open (ΔA _(ec–eo)) for the BCR group (p = 0.01) and the UKA group (p = 0.04) compared to the PS group.

Conclusions

This study found superior static balance ability after preservation of both cruciate ligaments in arthroplasty of the knee, indicating superior proprioceptive function. Hence, BCR implants could provide improved functional properties. Superior proprioceptive function of bicruciate-retaining implants can be an important factor in implant selection. Further prospective, randomized studies to investigate kinematics and long-term survivorship of bicruciate-retaining implants are needed.

Level of evidence

II.

     

Side-to-side asymmetries in landing mechanics from a drop vertical jump test are not related to asymmetries in knee joint laxity following anterior cruciate ligament reconstruction

Purpose

Asymmetries in knee joint biomechanics and increased knee joint laxity in patients following anterior cruciate ligament reconstruction (ACLR) are considered risk factors for re-tear or early onset of osteoarthritis. Nevertheless, the relationship between these factors has not been established. The aim of the study was to compare knee mechanics during landing from a bilateral drop vertical jump in patients following ACLR and control participants and to study the relationship between side-to-side asymmetries in landing mechanics and knee joint laxity.

Methods

Seventeen patients following ACLR were evaluated and compared to 28 healthy controls. Knee sagittal and frontal plane kinematics and kinetics were evaluated using three-dimensional motion capture (200 Hz) and two synchronized force platforms (1000 Hz). Static anterior and internal rotation knee laxities were measured for both groups and legs using dedicated arthrometers. Group and leg differences were investigated using a mixed model analysis of variance. The relationship between side-to-side differences in sagittal knee power/energy absorption and knee joint laxities was evaluated using univariate linear regression.

Results

A significant group-by-leg interaction (p = 0.010) was found for knee sagittal plane energy absorption, with patients having 25% lower values in their involved compared to their non-involved leg (1.22 ± 0.39 vs. 1.62 ± 0.40 J kg^?1). Furthermore, knee sagittal plane energy absorption was 18% lower at their involved leg compared to controls (p = 0.018). Concomitantly, patients demonstrated a 27% higher anterior laxity of the involved knee compared to the non-involved knee, with an average side-to-side difference of 1.2 mm (p < 0.001). Laxity of the involved knee was also 30% higher than that of controls (p < 0.001) (leg-by-group interaction: p = 0.002). No relationship was found between sagittal plane energy absorption and knee laxity.

Conclusions

Nine months following surgery, ACLR patients were shown to employ a knee unloading strategy of their involved leg during bilateral landing. However, this strategy was unrelated to their increased anterior knee laxity. Side-to-side asymmetries during simple bilateral landing tasks may put ACLR patients at increased risk of second ACL injury or early-onset osteoarthritis development. Detecting and correcting asymmetric landing strategies is highly relevant in the framework of personalized rehabilitation, which calls for complex biomechanical analyses to be applied in clinical routine.

Level of evidence

III.

     

Return to knee-strenuous sport after anterior cruciate ligament reconstruction: a report from a rehabilitation outcome registry of patient characteristics

Purpose

To characterise patients who returned to knee-strenuous sports after an anterior cruciate ligament (ACL) reconstruction.

Methods

Data from isotonic tests of muscle function and patient-reported outcome measures, Tegner activity scale (Tegner and Lysholm in Clin Orthop Relat Res 198:43–49, 1985), physical activity scale, knee injury and osteoarthritis scale and knee self-efficacy scale were extracted from a registry. The 157 included patients, 15–30 years of age, had undergone primary ACL reconstruction and were all involved in knee-strenuous sports, i.e. pre-injury Tegner of 6 or higher. Return to sport was studied in two different ways: return to pre-injury Tegner and return to knee-strenuous sport (Tegner 6).

Results

Fifty-two patients (33 %), who returned to pre-injury Tegner, 10 months after surgery, were characterised by better subjective knee function measured with the knee injury and osteoarthritis outcome score (p < 0.05), compared with patients who did not. These patients also had higher perceived self-efficacy of knee function (p < 0.01), measured with knee self-efficacy scale. Eighty-four patients (54 %) who returned to knee-strenuous sports, i.e. Tegner 6 or higher, were characterised by higher goals for physical activity (p < 0.01) and higher self-efficacy of future knee function (p < 0.05). Strength measurements showed that women who returned to sports were stronger in leg extension than women who did not. No differences were found in Limb Symmetry Index for knee strength or jumping ability.

Conclusion

Patients who returned to sports after ACL reconstruction had better subjective knee function and higher self-efficacy of knee function. Results highlight that further emphasis should be placed at psychological factors during rehabilitation of patients after ACLR.

Level of evidence

II.

     

Inadequate pre-operative glycaemic control in patients with diabetes mellitus adversely influences functional recovery after total knee arthroplasty

Purpose

Whilst inadequate glycaemic control is associated with an increase in perioperative complications following total knee arthroplasty, the impact of glycaemic control in this at-risk patient group remains ill-defined. Identification of at-risk patients would allow targeted pre-operative glycaemic control intervention.

Methods

One hundred consecutive patients with a diagnosis of diabetes mellitus and one hundred age, sex and BMI matched patients without diabetes undergoing total knee arthroplasty in a single institution were analysed between 2008 and 2013. Inadequate glycaemic control was defined as having an HbA1c of greater than 64 mmol/mol (8.0 % NGSP) measured within the 3 months before surgery. Patient demographics, diabetes management and complications of diabetes were recorded and used as explanatory variables to deliver a generalised linear model. This allows for relationships to be defined between change in patient-reported function (SF-36, WOMAC) and these explanatory variables.

Results

The patient group with concomitant diabetes exhibited smaller improvements in WOMAC and SF-36 physical component summary at 1 year after knee arthroplasty. This effect was most pronounced in the subset of patients with inadequate glycaemic control recorded in the early pre-operative period.

Conclusion

Patients with diabetes, particularly those with inadequate glycaemic control, exhibit less improvement at 1 year following knee arthroplasty than patients without diabetes mellitus. Clinical focus on modulating this factor in this at-risk group is warranted.

Level of evidence

III.

     

Does meniscal pathology alter gait knee biomechanics and strength post-ACL reconstruction?

Purpose

Individuals following anterior cruciate ligament reconstruction (ACLR) with concomitant meniscal pathology have a higher risk of developing knee osteoarthritis (OA) compared to those with isolated ACLR. Knee extensor weakness and altered dynamic knee joint biomechanics have been suggested to play a role in the development of knee OA following ACLR. This study investigated whether these factors differ in people following ACLR who have concomitant meniscal pathology compared to patients with isolated ACLR.

Methods

Thirty-three patients with isolated ACLR and 34 patients with ACLR and meniscal pathology underwent strength and gait assessment 12–24 months post-operatively. Primary measures were peak isometric knee extensor torque and knee adduction moment (peak and impulse). Secondary measures included peak knee flexion moment and knee kinematics (sagittal and transverse).

Results

There were no between-group differences in knee extensor strength [mean difference (95 % CI) 0.09 (?0.23 to 0.42) Nm/kg, n.s.], peak knee adduction moment [?0.02 (?0.54 to 0.49) Nm/(BW × HT) %, n.s.] or knee adduction moment impulse [0.01 (?0.15 to 0.17) Nm/(BW × HT) %, p = n.s.]. No between-group differences were found for any secondary measures.

Conclusions

No evidence was found to suggest that the higher prevalence of OA in patients with ACLR and meniscal pathology compared to patients with isolated ACLR is attributed to reduced knee muscle strength or altered knee joint biomechanics assessed 1–2 years post-surgery. Given that there is a higher incidence of knee OA in patients with concomitant meniscal pathology and ACLR, further investigation is needed so that population-specific rehabilitation protocols can be developed.

Level of evidence

III.

     

Post-operative deformation and extrusion of the discoid lateral meniscus following a partial meniscectomy with repair

Purpose

The purpose of this study was to investigate the morphology of the discoid lateral meniscus sequentially following a partial meniscectomy with repair using magnetic resonance imaging (MRI).

Methods

Nine patients with a symptomatic discoid lateral meniscus with a peripheral tear were enrolled in this study, and a partial meniscectomy with repair was performed arthroscopically. An MRI examination was performed 2 weeks after surgery (before weight bearing was permitted) and again 6 months after surgery (when sporting activities could resume). The width, height and distance of the discoid lateral meniscus were measured. The distance was defined as the distance between the edges of the discoid lateral meniscus and the tibia.

Results

The width of the anterior, middle and posterior segments significantly decreased from 2 weeks to 6 months after surgery. The height of the middle and posterior segments significantly increased from 2 weeks to 6 months after surgery, whereas the height of the anterior segment did not significantly change. The distance of the anterior, middle and posterior segments significantly decreased from 2 weeks to 6 months after surgery.

Conclusion

The discoid lateral meniscus exhibited deformation and extrusion from 2 weeks to 6 months after a partial meniscectomy with repair. Therefore, the function of load transmission might not be maintained appropriately after surgery.

Level of evidence

IV.

     

Knee laxity modifications after ACL rupture and surgical intra- and extra-articular reconstructions: intra-operative measures in reconstructed and healthy knees

Purpose

Quantifying the effects of anterior cruciate ligament (ACL) deficiency on knee joint laxity is fundamental for understanding the outcomes of its reconstruction techniques. The general aim of this study was to determine intra-operatively the main modifications in knee laxity before and after standard isolated intra-articular and additional extra-articular anterolateral reinforcement. Our main hypothesis was that laxity abnormalities, particularly axial rotation, can still result from these ACL reconstruction techniques.

Methods

Thirty-two patients with primary ACL deficiency were analysed by a navigation system immediately before and after each of the two reconstructions. Laxity measurements in terms of knee translations and rotations were taken during the anteroposterior drawer test, with internal–external rotation at 20° and 90° of flexion, and varus–valgus and pivot-shift tests. All these laxity measures were also taken originally from the contralateral healthy knee.

Results

With respect to the contralateral healthy knee, in the ACL-deficient knee significantly increased laxity (expressed in %) was found in the medial compared with that of the lateral compartment, respectively, 115 and 68 % in the drawer test at 20° flexion, and 55 and 46 % at 90° flexion. In the medial compartment, a significant 35 % increment was also observed for the coupled tibial anteroposterior translation during axial knee rotation at 20° of flexion. After isolated intra-articular reconstruction, normal values of anteroposterior laxity were found restored in the pivot-shift and drawer tests in the lateral compartment, but not fully in the medial compartment. After the reinforcement, laxity in the medial compartment was also found restored in the axial rotation test at 20° flexion.

Conclusion

In ACL reconstruction, with respect to the contralateral knee, intra-articular plus additional anterolateral reinforcement procedures do not restore normal joint laxity. This combined procedure over-constrained the lateral compartment, while excessive laxity still persists at the medial one.

Level of evidence

III.

     

The timing of surgical treatment of knee dislocations: a systematic review

Purpose

Traumatic knee dislocations (KDs) are unusual yet limb-threatening injuries; the timing of surgical intervention is still debated. A systematic review was performed to determine the optimal timing of surgery with respect to injury pattern.

Methods

A comprehensive search of Medline, EMBASE, and Cochrane Central Register of Controlled Trials was performed for studies published between 1 January 1974 and 20 April 2014 on the surgical management of “knee dislocation” and “multiligament knee injuries”. Surgical timing was classified as acute, chronic, or staged. A systematic review was performed for patients with KD-III according to Schenck’s classification using individual patient data.

Results

Twelve studies including 150 patients (153 knees) with KDs fulfilled the study requirements. Sixty-nine cases with KD-IIIM and 84 cases with KD-IIIL were identified. Excellent or good results were demonstrated in 79.1 % (34 cases) of cases managed with staged treatment versus 58.4 % (45 cases) of cases undergoing acute surgery (p = 0.02), and versus 45.5 % (15 cases) of cases undergoing chronic surgery (p = 0.002). No statistically significant difference was found in the percentage of excellent or good results between the acute and chronic surgery groups (n.s.), or between the KD-IIIM and KD-IIIL groups (n.s.).

Conclusion

Staged treatment yields the best clinical results for patients with KD-III. No statistically significant difference was shown in the clinical results between acute surgery and chronic surgery groups.

Level of evidence

IV.

     

ACL-reconstructed and ACL-deficient individuals show differentiated trunk,hip, and knee kinematics during vertical hops more than 20 years post-injury

Purpose

Little is known regarding movement strategies in the long term following injury of the anterior cruciate ligament (ACL), and even less about comparisons of reconstructed and deficient knees in relation to healthy controls. The present purpose was to compare trunk, hip, and knee kinematics during a one-leg vertical hop (VH) ~20 years post-ACL injury between persons treated with surgery and physiotherapy (ACL_R), solely physiotherapy (ACL_PT), and controls (CTRL). Between-leg kinematic differences within groups were also investigated.

Methods

Sixty-six persons who suffered unilateral ACL injury on average 23 ± 2 years ago (32 ACL_R, 34 ACL_PT) and 33 controls performed the VH. Peak trunk, hip, and knee angles during Take-off and Landing phases recorded with a 3D motion capture system were analysed with multivariate statistics.

Results

Significant group effects during both Take-off and Landing were found, with ACL_PT differing from CTRL in Take-off with a combination of less knee flexion and knee internal rotation, and from both ACL_R and CTRL in Landing with less hip and knee flexion, knee internal rotation, and greater hip adduction. ACL_R also presented different kinematics to ACL_PT and CTRL in Take-off with a combination of greater trunk flexion, hip flexion, hip internal rotation, and less knee abduction, and in Landing with greater trunk flexion and hip internal rotation. Further, different kinematics and hop height were found between legs within groups in both Take-off and Landing for both ACL groups, but not for CTRL.

Conclusion

Different kinematics for the injured leg for both ACL groups compared to CTRL and between treatment groups, as well as between legs within treatment groups, indicate long-term consequences of injury. Compensatory mechanisms for knee protection seem to prevail over time irrespective of initial treatment, possibly increasing the risk of re-injury and triggering the development of osteoarthritis. Detailed investigation of movement strategies during the VH provides important information and a more comprehensive evaluation of knee function than merely hop height. More attention should also be given to the trunk and hip in clinics when evaluating movement strategies after ACL injury.

Level of evidence

Prospective cohort study, Level II.

     

Effects of prophylactic knee bracing on patellar tendon loading parameters during functional sports tasks in recreational athletes

Purpose

This study investigated the effects of prophylactic knee bracing on patellar tendon loading parameters.

Methods

Twenty recreational athletes (10 male and 10 female) from different athletic disciplines performed run, cut and single leg hop movements under two conditions (prophylactic knee brace/no-brace). Lower extremity kinetics and kinematics were examined using a piezoelectric force plate and three-dimensional motion capture system. Patellar tendon loading was explored using a mathematical modelling approach, which accounted for co-contraction of the knee flexors. Tendon loading parameters were examined using 2 (brace) × 3 (movement) × 2 (sex) mixed ANOVAs.

Results

Tendon instantaneous load rate was significantly reduced in female athletes in the run (brace 289.14 BW/s no-brace 370.06 BW/s) and cut (brace 353.17 BW/s/no-brace 422.01 BW/s) conditions whilst wearing the brace.

Conclusions

Female athletes may be able to attenuate their risk from patellar tendinopathy during athletic movements, through utilization of knee bracing, although further prospective research into the prophylactic effects of knee bracing is required before this can be clinically substantiated.

     

Agreement between radiological and computer navigation measurement of lower limb alignment

Purpose

Accurate and reproducible measurements of limb alignment are necessary for planning, performing and evaluation of reconstructive knee surgery. Aim of this study was the comparison of the alignment measured on long-leg standing radiographs with the intraoperative data from a navigation system.

Methods

The records of 135 consecutive patients who received computer-assisted TKA were examined. Technical quality of the long-leg radiographs (LLRs) was classified good, acceptable or poor according to the rotation of the leg. The difference between radiographic and navigation measurements of leg alignment was assessed.

Results

Preoperative LLRs were rated as good 56.3 % (71.1 % postoperatively), acceptable in 37.0 % (20.0 % postoperatively) and poor in 6.7 % (8.9 % postoperatively). The median difference between radiographic and navigation measurements increased with reduced quality of the LLR [good 1.5° (range 0.0°–9.9°), acceptable 2.5° (range 0.0°–15.0°), poor 4.5° (range 0.2°–9.5°)], but not with greater deformity. Median difference between both measurements in good radiographs was 1.7° (range 0.0°–9.9°) preoperatively and 1.2° (range 0.0°–7.0°) postoperatively.

Conclusion

Difference between radiographic and navigation measurements of lower limb alignment is low if the LLR are obtained in neutral rotation. Larger differences between both measurements can occur even under these ideal conditions, and it is still unclear which measurement is closer to reality. Therefore, even if a navigation system is used during surgery, long-leg standing radiographs should currently not be abandoned.

Level of evidence

III.

     

Courses of change in knee adduction moment and lateral thrust differ up to 1 year after TKA

Purpose

In total knee arthroplasty (TKA), dynamic knee loading may loosen the artificial joint and bone or cause polyethylene wear after prolonged use. TKA decreases knee adduction moment at 6 months, but this effect is lost by 1 year post-operatively. However, lateral thrust after TKA has not been clarified. We hypothesized that like knee adduction moment, lateral thrust would return to baseline levels by 1 year post-operatively.

Methods

Participants were 15 patients who underwent TKA for medial knee OA. Japanese Orthopaedic Association (JOA) score, numeric rating scale, and gait analysis (measurement of peak knee adduction moment, knee varus angle at peak knee adduction moment, lateral thrust, and gait speed) were performed preoperatively (baseline) and 3 weeks, 3 and 6 months, and 1 year post-operatively.

Results

JOA score improved from 55 ± 9.8 to 78 ± 12.1 at 1 year post-operatively, and pain decreased significantly from baseline at each follow-up (p < 0.001). Significant increases in gait speed were observed at 6 months and 1 year (p < 0.001). Peak knee adduction moment during stance phase was significantly lower at 3 weeks, 3 months, and 6 months compared to baseline (p < 0.05), but no significant changes were seen at 1 year. Knee varus at peak knee adduction moment did not differ significantly between any measurement points, while lateral thrust was decreased at 6 months and 1 year compared to baseline (p < 0.05).

Conclusions

Temporal courses of changes up to 1 year after TKA differed between knee adduction moment and lateral thrust, so our hypothesis was rejected.

Level of evidence

IV.

     

Knee hyperextension does not adversely affect dynamic in vivo kinematics after anterior cruciate ligament reconstruction

Purpose

To evaluate the effect of knee hyperextension on dynamic in vivo kinematics after anterior cruciate ligament reconstruction (ACL-R).

Methods

Forty-two patients underwent unilateral ACL-R. Twenty-four months after surgery, subjects performed level walking and downhill running on a treadmill while dynamic stereo radiographs were acquired at 100 (walking) and 150 Hz (running). Tibiofemoral motion was determined using a validated model-based tracking process, and tibiofemoral translations/rotations were calculated. The range of tibiofemoral motions from 0 to 10% of the gait cycle (heel strike to early stance phase) and side-to-side difference (SSD) were calculated. Maximum knee extension angle of ACL-reconstructed knees during walking was defined as active knee extension angle in each subject. Correlations between maximum knee extension angle and tibiofemoral kinematics data were evaluated using Spearman’s rho (P < 0.05).

Results

No significant correlation was observed between maximum knee extension angle and the range of anterior tibial translation during functional activities in the ACL-R knees. Maximum knee extension angle was weakly correlated with internal tibial rotation range in ACL-R knee during running (ρ = 0.376, P = 0.014); however, maximum extension angle was not correlated with SSD of internal tibial rotation. SSD of internal tibial rotation was ?0.4° ± 1.9° (walking), ?1.6° ± 3.1° (running), indicating ACL-R restored rotatory knee range of motion during functional movements.

Conclusion

Knee hyperextension was not significantly correlated with greater SSD of anterior translation and internal rotation. The clinical relevance is that knee hyperextension does not adversely affect kinematic outcomes after ACL-R and that physiologic knee hyperextension can be restored after ACL-R when knee hyperextension is present.

Level of evidence

III.

     

The presence and influence of mild depressive symptoms on post-operative pain perception following primary total knee arthroplasty

Purpose

To evaluate the influence of mild depression on pain perception after total knee arthroplasty (TKA).

Methods

Hamilton depression (HDRS) and numeric rating (NRS) scales were used to evaluate depression severity and pain perception at various intervals surrounding TKA. The Hospital for Special Surgery (HSS) knee and pain scores (NRS) in patients with signs of mild depression (HDRS < 20 points) were compared to a control group of patients with no signs of depression (HDRS < 8 points).

Results

Prior to surgery, there were no statistical differences in pain perception (NRS) or individual components of HSS knee score including range of motion, pain, and function between patients with mild depression compared to controls. However, following surgery, patients with signs of mild depression were more likely to report more pain (p < 0.001) and have lower HSS scores even at 1 year post-operatively (p < 0.001).

Conclusions

A significant number of patients in this series undergoing routine primary TKA had signs of subclinical depression. These patients are more likely to report increased pain even at 1 year following surgery compared to patients without signs of depression preoperatively. Psychometric evaluation prior to surgery can help identify the at-risk patient and allow for proper management of patient expectations, thus improving clinical results and patients’ satisfaction after TKA.

Level of evidence

Prospective comparative study, II.