Background
Most knee surgeons have believed during TKA neutral mechanical alignment should be restored. A number of patients may exist, however, for whom neutral mechanical alignment is abnormal. ...Patients with so-called “constitutional varus” knees have had varus alignment since they reached skeletal maturity. Restoring neutral alignment in these cases may in fact be abnormal and undesirable and would likely require some degree of medial soft tissue release to achieve neutral alignment.
Questions/purposes
We investigated what percentage of the normal population has constitutional varus knees and what are the contributing factors.
Subjects and Methods
We recruited a cohort of 250 asymptomatic adult volunteers between 20 and 27 years old for this cross-sectional study. All volunteers had full-leg standing digital radiographs on which 19 alignment parameters were analyzed. The incidence of constitutional varus alignment was determined and contributing factors were analyzed using multivariate prediction models.
Results
Thirty-two percent of men and 17% of women had constitutional varus knees with a natural mechanical alignment of 3° varus or more. Constitutional varus was associated with increased sports activity during growth, increased femoral varus bowing, an increased varus femoral neck-shaft angle, and an increased femoral anatomic mechanical angle.
Conclusions
An important fraction of the normal population has a natural alignment at the end of growth of 3° varus or more. This might be a consequence of Hueter-Volkmann’s law. Restoration of mechanical alignment to neutral in these cases may not be desirable and would be unnatural for them.
Level of Evidence
Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
There is increasing evidence that for a number of patients, neutral alignment is not normal. Patients with so-called constitutional varus have been in varus alignment since the end of their growth. ...Restoring neutral alignment in these cases may not be the best option for these patients since it is abnormal to them. We recently performed a number of observational studies to find out how patients develop constitutional varus, how these patients can be recognized, and which factors contribute. A cohort of 800 young patients was analyzed to determine the influence of activity level on growth and the development of lower-leg alignment. At the same time, 250 asymptomatic adults between 20 and 27 years were analyzed to determine the incidence of constitutional varus. The results showed that 32% of adult men and 17% of adult women had constitutional varus knees with a natural mechanical alignment ≥3° varus. Constitutional varus was associated with increased sports activity during growth and began to become apparent at the time of growth spurt. Based on these data, we believe that an important fraction of the normal population has a natural alignment at the end of growth of ≥3° varus. This may be a consequence of Hueter-Volkmann's law. Restoration of mechanical alignment to neutral in these cases therefore may not be desirable and in fact unnatural for them.
In 1879, the French surgeon Segond described the existence of a ‘pearly, resistant, fibrous band’ at the anterolateral aspect of the human knee, attached to the eponymous Segond fracture. To date, ...the enigma surrounding this anatomical structure is reflected in confusing names such as ‘(mid‐third) lateral capsular ligament’, ‘capsulo‐osseous layer of the iliotibial band’ or ‘anterolateral ligament’, and no clear anatomical description has yet been provided. In this study, the presence and characteristics of Segond's ‘pearly band’, hereafter termed anterolateral ligament (ALL), was investigated in 41 unpaired, human cadaveric knees. The femoral and tibial attachment of the ALL, its course and its relationship with nearby anatomical structures were studied both qualitatively and quantitatively. In all but one of 41 cadaveric knees (97%), the ALL was found as a well‐defined ligamentous structure, clearly distinguishable from the anterolateral joint capsule. The origin of the ALL was situated at the prominence of the lateral femoral epicondyle, slightly anterior to the origin of the lateral collateral ligament, although connecting fibers between the two structures were observed. The ALL showed an oblique course to the anterolateral aspect of the proximal tibia, with firm attachments to the lateral meniscus, thus enveloping the inferior lateral geniculate artery and vein. Its insertion on the anterolateral tibia was grossly located midway between Gerdy's tubercle and the tip of the fibular head, definitely separate from the iliotibial band (ITB). The ALL was found to be a distinct ligamentous structure at the anterolateral aspect of the human knee with consistent origin and insertion site features. By providing a detailed anatomical characterization of the ALL, this study clarifies the long‐standing enigma surrounding the existence of a ligamentous structure connecting the femur with the anterolateral tibia. Given its structure and anatomic location, the ALL is hypothesized to control internal tibial rotation and thus to affect the pivot shift phenomenon, although further studies are needed to investigate its biomechanical function.
Background:
Although meniscal allograft transplantation (MAT) has been performed for nearly 30 years, there are few long-term published studies of the technique.
Hypothesis/Purpose:
The goal of this ...study was to report the long-term results of a patient cohort whose medium-term results have been reported and to evaluate whether the results are maintained in the long term or deteriorate after a certain period. The hypothesis was that the subjective, clinical, and radiographic results are consistent in the long term without significant deterioration.
Study Design:
Case series; Level of evidence, 4.
Methods:
Thirty patients from the original cohort of 49 patients (50 MATs) who underwent MAT at least 9 years before this study were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS); Lysholm, Tegner, and Short Form–36 scores; and a visual analog score for pain. A standardized clinical examination was performed to objectively evaluate knee-related symptoms. Standard weightbearing radiographs, including a full-leg standing radiograph, were performed to evaluate joint space narrowing and any progression of osteoarthritis and malalignment. These results, at a mean follow-up time of 12 years and 8 months (152 months; range, 112-216 months), were compared with the preoperative data and the outcome results at medium-term follow-up (mean, 8 years and 9 months).
Results:
Of the original 49 patients, 6 (12.2%) required conversion to a total knee arthroplasty during the study period and were considered failures, and 17 (34.7%) required a second surgical procedure during the study period. Excluding the 6 total knee arthroplasty cases, 90% of patients reported being very satisfied or satisfied and would undergo the procedure again. Only 1 patient reported not wanting to undergo the procedure again. Results of the visual analog score, KOOS and all KOOS subscales, Lysholm, and Short Form–36 all showed a statistically significant improvement at estimated follow-up periods of 7.5 and 12.5 years compared with preoperative scores. There was no statistically significant difference for these scores between 7.5 and 12.5 years postoperatively. Despite the improvement in outcome scores, the Tegner activity level score remained unchanged during the entire follow-up period. Regarding radiographic outcomes, there was a progressive increase in the Kellgren-Lawrence rating over the study period. There was a statistically significant (P = .0208) progressive joint space narrowing between estimates at the 7.5-year (5.45 mm) and 12.5-year (4.95 mm) follow-up. However, there was no statistically significant (P = .6724) difference in absolute value of alignment deviation from the 0° mechanical axis between 7.5 years (2.32°) and 12.5 years (2.51°) postoperatively. There was no difference between medial and lateral transplants.
Conclusion:
Despite an increase in joint space narrowing, MAT resulted in significant improvements in pain and functional outcomes over the study period. There was no change in these improvements between the medium- and long-term follow-up period. This study confirms the good and consistent results found in the literature concerning satisfaction, pain resolution, and functional scores at long-term follow-up.
Single-leg hop tests are commonly performed in the forward direction to evaluate functional performance. However, athletes move in multiple directions during pivoting sports. The first aim of this ...study was to examine test–retest reliability of single-leg hop tests in the forward, medial and rotational direction in non-injured athletes. Second, the discriminative ability to detect leg asymmetries with these hop tests in anterior cruciate ligament (ACL) reconstructed athletes was determined.
Sixteen recreational non-injured participants (eight females, eight males; 22.4 ± 1.9 years) were tested twice (one-week interval) and performed the single hop for distance (SH), triple hop for distance (TH), medial side triple hop for distance (MSTH) and 90° medial rotation hop for distance (MRH). Intraclass correlation coefficients (ICCs), standard errors of measurement (SEM) and smallest detectable differences (SDD) were calculated. Discriminative ability was determined in 32 ACL-reconstructed participants (four females, 28 males; 24.4 ± 4.6 years; six months postoperative) who performed the same hop tests once.
The ICCs ranged between 0.93 and 0.98. The SEM and SDD were respectively 2.6–4.1% and 7.2–11.3% of the mean hop distance of the group. The proportion (%) of ACL-reconstructed participants passing the ≥90% limb symmetry cut-off was 62.5 (SH), 59.4 (TH), 40.6 (MSTH) and 46.9 (MRH).
Excellent test–retest reliability of forward, medial and rotational hop tests was found. This allows clinicians to make informed interpretations of changes in hop test distances when retesting athletes. Medial and rotational hop tests are more likely to show limb asymmetries in ACL-reconstructed participants compared to forward hop tests.
Purpose The purpose of this study was to investigate the relation of the Segond fracture with the anterolateral ligament (ALL) of the knee. Methods To identify the soft-tissue structure causative for ...the Segond fracture, a study was set up to compare anatomic details of the tibial insertion of the recently characterized ALL in cadaveric knees (n = 30) with radiologic data obtained from patients (n = 29) with a possible Segond fracture based on an imaging protocol search. The spatial relation of the ALL footprint with well-identifiable anatomic landmarks at the lateral aspect of the knee was determined, and this was repeated for the Segond fracture bed. Results In all of the included cadaveric knees, a well-defined ALL was found as a distinct ligamentous structure connecting the lateral femoral epicondyle with the anterolateral proximal tibia. The mean distance of the center of the tibial ALL footprint to the center of the Gerdy tubercle (GT-ALL distance) measured 22.0 ± 4.0 mm. The imaging database search identified 26 patients diagnosed with a Segond fracture. The mean GT-Segond distance measured 22.4 ± 2.6 mm. The observed difference of 0.4 mm (95% confidence interval, –1.5 to 2.2 mm) between the GT-ALL distance and GT-Segond distance was neither statistically significant ( P = .70) nor clinically relevant. Conclusions The results of this study confirmed the hypothesis that the ALL inserts in the region on the proximal tibia from where Segond fractures consistently avulse, thus suggesting that the Segond fracture is actually a bony avulsion of the ALL. Clinical Relevance Although the Segond fracture remains a useful radiographic clue for indirect detection of anterior cruciate ligament injuries, the Segond fracture should be considered a frank ligamentous avulsion itself.
Purpose
Implementation of morphometric reference data from the contralateral, unaffected lower limb is suggested when reconstructing the coronal plane alignment in TKA. Limited information, however, ...is available which confirms this left-to-right symmetry in coronal alignment based upon radiographs. The purpose of the study was, therefore, (1) to verify if a left-to-right symmetry is present and (2) to assess whether the contralateral lower limb would be a reliable reference for reconstructing the frontal plane alignment.
Methods
Full-leg standing radiographs of 250 volunteers (male, 125; female,125) were reviewed for three alignment parameters (Hip–Knee–Ankle angle (HKA), Femoral Mechanical Angle (FMA) and Tibial Mechanical Angle (TMA)). Evaluation of assumed left-to-right symmetry was performed according to two coronal alignment classifications (HKA subdivisions (HKA) and limb, femoral and tibial phenotypes (HKA, FMA and TMA)). Inter- and within-subject variability was calculated, along with correlations coefficients (
r
) and coefficients of determination (
r
2
). Reliability of the contralateral limb as a personalized reference to reconstruct the constitutional alignment was investigated by intervals, expanding by 1° increments (0.5° increment both to varus and valgus) around the right knee alignment parameters. Subsequently, it was verified whether or not the left knee parameters fell within this interval.
Results
Symmetrical distribution in coronal alignment was found in 79% (HKA subdivision) and 59% (limb phenotype) of the cohort. Gender differences were present for the most common symmetric limb phenotypes (VAR
HKA
3° (23.2%) in males and NEU
HKA
0° (38.4%) in females). Inter-subject variability was more prominent than the within-subject side differences for all parameters. Correlations analyses revealed mostly moderate correlations between the alignment measurements. Coefficients of determination showed overall weak left-to-right relationship, except for a moderate predictability for HKA (
r
2
= 0.538,
p
< 0.001) and FMA (
r
2
= 0.618,
p
< 0.001) in females. FMA and TMA marked weak predictive values for contralateral HKA. Only 60% of left knees were referenced within a 3° interval around the right knee.
Conclusion
No strict left-to-right symmetry was observed in coronal alignment measurements. There is insufficient left-to-right agreement to consider the concept of the contralateral unaffected limb as an idealized reference for frontal plane alignment reconstruction based upon full-leg standing radiographs.
Level of evidence
I.
Purpose
Although the occurrence of early osteoarthritis (OA) is commonly associated with a history of anterior cruciate ligament (ACL) reconstruction, its exact prevalence in these patients remains ...unknown. The goal of this study was to review the current literature on long-term radiographic outcome after autologous ACL reconstruction and subsequently perform a meta-analysis to obtain evidence-based prevalences of OA at a mean of 10 years after surgery. In addition, this report aimed at identifying the relationship between meniscal status and the occurrence of radiographic OA in the ACL reconstructed knee.
Methods
A systematic review of the literature was performed in PubMed MEDLINE, EMBASE and Cochrane Library databases to identify all studies concerning radiographic outcome after autologous ACL reconstruction with a follow-up of minimum 10 years. Meta-analyses were performed to obtain the average prevalence of OA and the difference between patients with and without meniscectomy. Considered study estimates were the log-transformed odds and odds ratios, the latter expressing the effect of meniscectomy on OA.
Results
A total of 16 studies could be included for meta-analysis, accounting for 1554 ACL reconstructions performed between 1978 and 1997. Of these knees, 453 (28 %) showed radiological signs of osteoarthritis (IKDC grade C or D). Furthermore, 50 % of the patients with meniscectomy had osteoarthritis, compared with 16 % of the patients without meniscectomy. The combined odds ratio for meniscectomy equals 3.54 (95 % CI 2.56–4.91).
Conclusions
The main finding of this meta-analysis is that the prevalence of radiographic knee OA after ACL reconstruction is lower than commonly perceived. However, associated meniscal resection dramatically increases the risk for developing OA.
Level of evidence
Level III.
Abstract Restoration of neutral mechanical alignment is one of the prerequisites for long-term TKA survival. This study aimed to investigate the effect of deviations from neutral alignment on bone ...and implant stress and on ligament strain. Using a previously validated finite element model, a neutrally aligned TKA model was compared to 3 different varus and valgus configurations induced by tibial or by femoral component only and by both component simultaneously. Each model underwent a 2500 N vertical load simulating the peak walking force. Varus and valgus alignment increased polyethylene and bone stress, and altered ligament strains, as compared to the neutral aligned model. Changes in alignment of the tibial component were always associated with more detrimental effects compared to the one of the femoral component.
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