Osteotomy around the painful degenerative varus knee has broader indications than conventionally described but must follow a strict planning process: ESSKA Formal Consensus Part I.

PURPOSE: The European consensus was designed with the objective of combining science and expertise to produce recommendations that would educate and provide guidance in the treatment of the painful degenerative varus knee. Part I focused on indications and planning. METHODS: Ninety-four orthopaedic surgeons from 24 European countries were involved in the consensus, which focused on the most common indications for osteotomy around the knee. The consensus was performed according to an established ESSKA methodology. The questions and recommendations made were initially designed by the consensus steering group. And 'best possible' answers were provided based upon the scientific evidence available and the experience of the experts. The statements produced were further evaluated by ratings and peer review groups before a final consensus was reached. RESULTS: There is no reliable evidence to exclude patients based on age, gender or body weight. An individualised approach is advised; however, cessation of smoking is recommended. The same applies to lesser degrees of patellofemoral and lateral compartment arthritis, which may be accepted in certain situations. Good-quality limb alignment and knee radiographs are a mandatory requirement for planning of osteotomies, and Paley's angles and normal ranges are recommended when undertaking deformity analysis. Emphasis is placed upon the correct level at which correction of varus malalignment is performed, which may involve double-level osteotomy. This includes recognition of the importance of individual bone morphology and the maintenance of a physiologically appropriate joint line orientation. CONCLUSION: The indications of knee osteotomies for painful degenerative varus knees are broad. Part I of the consensus highlights the versatility of the procedure to address multiple scenarios with bespoke planning for each case. Deformity analysis is mandatory for defining the bone morphology, the site of the deformity and planning the correct procedure. LEVEL OF EVIDENCE: Level II, consensus.

Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II.

PURPOSE: The purpose of the European consensus was to provide recommendations for the treatment of patients with a painful degenerative varus knee using a joint preservation approach. Part II focused on surgery, rehabilitation and complications after tibial or femoral correction osteotomy. METHODS: Ninety-four orthopaedic surgeons from 24 countries across Europe were involved in the consensus, which focused on osteotomies around the knee. The consensus was performed according to the European Society for Sports Traumatology, Knee Surgery and Arthroscopy consensus methodology. The steering group designed the questions and prepared the statements based on the experience of the experts and the evidence of the literature. The statements were evaluated by the ratings of the peer-review groups before a final consensus was released. RESULTS: The ideal hinge position for medial opening wedge high tibial osteotomy (MOW HTO) should be at the upper level of the proximal tibiofibular joint, and for lateral closing wedge distal femoral osteotomy (LCW DFO) just above the medial femoral condyle. Hinge protection is not mandatory. Biplanar osteotomy cuts provide more stability and quicker bony union for both MOW HTO and LCW DFO and are especially recommended for the latter. Osteotomy gap filling is not mandatory, unless structural augmentation for stability is required. Patient-specific instrumentation should be reserved for complex cases by experienced hands. Early full weight-bearing can be adopted after osteotomy, regardless of the technique. However, extra caution should be exercised in DFO patients. Osteotomy patients should return to sports within 6 months. CONCLUSION: Clear recommendations for surgical strategy, rehabilitation and complications of knee osteotomies for the painful degenerative varus knee were demonstrated. In Part 2 of the consensus, high levels of agreement were reached by experts throughout Europe, under variable working conditions. Where science is limited, the collated expertise of the collaborators aimed at providing guidance for orthopaedic surgeons developing an interest in the field and highlighting areas for potential future research. LEVEL OF EVIDENCE: Level II, consensus.

The use of injectable orthobiologics for knee osteoarthritis: A European ESSKA-ORBIT consensus. Part 1-Blood-derived products (platelet-rich plasma).

PURPOSE: The aim of this European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) consensus is to provide recommendations based on evidence and expert opinion to improve indications, decision-making and administration-related aspects when using blood-derived orthobiologics (for simplicity indicated as PRP-platelet-rich plasma-with PRP being the most common product) for the management of knee osteoarthritis (OA). METHODS: Leading European expert clinicians and scientists were divided into a steering group, a rating group and a peer review group. The steering group prepared 28 question-statement sets divided into three sections: PRP rationale and indications, PRP preparation and characterisation and PRP protocol. The quality of the statements received grades of recommendation ranging from A (high-level scientific support) to B (scientific presumption), C (low-level scientific support) or D (expert opinion). The question-statement sets were then evaluated by the rating group, and the statements scored from 1 to 9 based on their degree of agreement with the statements produced by the steering group. Once a general consensus was reached between the steering and rating groups, the document was submitted to the peer review group who evaluated the geographic adaptability and approved the document. A final combined meeting of all the members of the consensus was held to produce the official document. RESULTS: The literature review on the use of blood-derived products for knee OA revealed that 9 of 28 questions/statements had the support of high-level scientific literature, while the other 19 were supported by a medium-low scientific quality. Three of the 28 recommendations were grade A recommendations: (1) There is enough preclinical and clinical evidence to support the use of PRP in knee OA. This recommendation was considered appropriate with a strong agreement (mean: 8). (2) Clinical evidence has shown the effectiveness of PRP in patients for mild to moderate degrees of knee OA (KL ≤ 3). This recommendation was considered appropriate with a strong agreement (mean: 8.1). (3) PRP injections have been shown to provide a longer effect in comparison to the short-term effect of CS injections. They also seem to provide a safer use profile with less potential related complications. This recommendation was considered appropriate with a very strong agreement (mean: 8.7). Six statements were grade B recommendations, 7 were grade C and 12 were grade D. The mean rating score was 8.2 ± 0.3. CONCLUSIONS: The consensus group reached a high level of agreement on all the questions/statements despite the lack of clear evidence for some questions. According to the results from this consensus group, given the large body of existing literature and expert opinions, PRP was regarded as a valid treatment option for knee OA and as a possible first-line injectable treatment option for nonoperative management of knee OA, mainly for KL grades 1-3. LEVEL OF EVIDENCE: Level II.

Platelet-rich plasma injections for the management of knee osteoarthritis: The ESSKA-ICRS consensus. Recommendations using the RAND/UCLA appropriateness method for different clinical scenarios.

PURPOSE: The aim of this consensus was to develop evidence- and expert-based patient-focused recommendations on the appropriateness of intra-articular platelet-rich plasma (PRP) injections in different clinical scenarios of patients with knee osteoarthritis (OA). METHODS: The RAND/UCLA Appropriateness Method was used by the European Society of Sports Traumatology, Knee Surgery, and Arthroscopy (ESSKA), as well as the International Cartilage Regeneration and Joint Preservation Society (ICRS) to reach a consensus and produce recommendations for specific patient categories combining best available scientific evidence with the collective judgement of a panel of experts. RESULTS: Scenarios were defined based on first treatment vs first injective treatment vs second injective treatment, age (<50/50-65/66-80/>80), tibiofemoral vs patellofemoral involvement, OA level (Kellgren-Lawrence/KL 0-I/II-III/IV), and joint effusion (dry knee, minor-mild or major effusion). Out of 216 scenarios, in 84 (38.9%) the indication was considered appropriate, in 9 (4.2%) inappropriate and in 123 (56.9%) uncertain. The parameters associated with the highest consensus were PRP use after failed injective treatments (62.5%), followed by PRP after failed conservative treatments and KL 0-III scenarios (58.3%), while the highest uncertainty was found for PRP use as first treatment and KL IV OA (91.7% and 87.5% of uncertain scenarios, respectively). CONCLUSION: This ESSKA-ICRS consensus established recommendations on the appropriateness or inappropriateness of PRP injections for the treatment of knee OA, providing a useful reference for clinical practice. PRP injections are considered appropriate in patients aged ≤80 years with knee KL 0-III OA grade after failed conservative non-injective or injective treatments, while they are not considered appropriate as first treatment nor in KL IV OA grade. LEVEL OF EVIDENCE: Level I.

Management of anterior cruciate ligament revision in adults: the 2022 ESSKA consensus part III-indications for different clinical scenarios using the RAND/UCLA appropriateness method.

PURPOSE: The aim of the ESSKA 2022 consensus Part III was to develop patient-focused, contemporary, evidence-based, guidelines on the indications for revision anterior cruciate ligament surgery (ACLRev). METHODS: The RAND/UCLA Appropriateness Method (RAM) was used to provide recommendations on the appropriateness of surgical treatment versus conservative treatment in different clinical scenarios based on current scientific evidence in conjunction with expert opinion. A core panel defined the clinical scenarios with a moderator and then guided a panel of 17 voting experts through the RAM tasks. Through a two-step voting process, the panel established a consensus as to the appropriateness of ACLRev for each scenario based on a nine-point Likert scale (in which a score in the range 1-3 was considered 'inappropriate', 4-6 'uncertain', and 7-9 'appropriate'). RESULTS: The criteria used to define the scenarios were: age (18-35 years vs 36-50 years vs 51-60 years), sports activity and expectation (Tegner 0-3 vs 4-6 vs 7-10), instability symptoms (yes vs no), meniscus status (functional vs repairable vs non-functional meniscus), and osteoarthritis (OA) (Kellgren-Lawrence [KL] grade 0-I-II vs grade III). Based on these variables, a set of 108 clinical scenarios was developed. ACLRev was considered appropriate in 58%, inappropriate in 12% (meaning conservative treatment is indicated), and uncertain in 30%. Experts considered ACLRev appropriate for patients with instability symptoms, aged ≤ 50 years, regardless of sports activity level, meniscus status, and OA grade. Results were much more controversial in patients without instability symptoms, while higher inappropriateness was related to scenarios with older age (51-60 years), low sporting expectation, non-functional meniscus, and knee OA (KL III). CONCLUSION: This expert consensus establishes guidelines as to the appropriateness of ACLRev based on defined criteria and provides a useful reference for clinical practice in determining treatment indications. LEVEL OF EVIDENCE: II.

Editorial Commentary: Surgical Management of Degenerative Meniscus Lesions Is a Second- But Not a First-Line Treatment.

The 20-year progression of osteoarthritis (OA) after arthroscopic partial meniscectomy (APM) in patients aged between 50 and 70 bears a long-term risk of conversion to total knee arthroplasty of 15.7%. Negative predictors at the time of surgery are the degree of knee OA, lateral meniscectomy, age at surgery, and malalignment. This confirms the evolution of the natural history of knee OA, but most importantly, it provides arguments to further restrain indications of APM in degenerative meniscus lesions (DMLs). An improved understanding of the consequences of APM for DMLs allows to increasingly limit the indications of this procedure, thus rendering it pertinent and efficient. Over the last years, the numbers of APM have been declining in several countries. This reduction required many surgeons to undergo a paradigm shift. This change cannot be induced by an anathema but by educational programs and guidelines based on broad consensus of the surgical communities, like the 2016 European Meniscus Consensus Project initiated by the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA). It provided a reference frame for the management of DMLs, based both on scientific literature and balanced expert opinion. The proposed decisional algorithm introduced APM not as a first- but as a second-line treatment of DMLs in symptomatic patients. A recent survey presented earlier this month at the international conference "The Meniscus" among ESSKA members showed that a majority of the 460 respondents were familiar with the ESSKA consensus and that 66% of them changed their practice following its publication. Paradigm changes take time. The history of meniscus repair showed that it takes many years to develop medical and surgical practice. And there is a good reason for this. Paradigms are not fashionable that come and go with the seasons. The medical and orthopaedic communities need to get them right by improving clinical science and balancing discussions.

Management of traumatic meniscus tears: the 2019 ESSKA meniscus consensus.

PURPOSE: The importance of meniscus integrity in the prevention of early osteoarthritis is well known, and preservation is accepted as the primary goal. The purpose of the ESSKA (European Society for Sports Traumatology, Knee Surgery and Arthroscopy) European consensus on traumatic meniscus tears was to provide recommendations for the treatment of meniscus tears based on both scientific evidence and the clinical experience of knee experts. METHODS: Three groups of surgeons and scientists elaborated and ratified the so-called formal consensus process to define the recommendations for the management of traumatic meniscus tears. A traumatic meniscus tear was defined as a tear with an acute onset of symptoms caused by a sufficient trauma. The expert groups included a steering group of eight European surgeons and scientists, a rating group of another nineteen European surgeons, and a peer review group. The steering group prepared twenty-seven question and answer sets based on the scientific literature. The quality of the answers received grades of A (a high level of scientific support), B (scientific presumption), C (a low level of scientific support) or D (expert opinion). These question and answer sets were then submitted to and evaluated by the rating group. All answers were scored from 1 (= totally inappropriate) to 9 (= totally appropriate) points. Thereafter, the comments of the members of the rating group were incorporated by the steering group and the consensus was submitted to the rating group a second time. Once a general consensus was reached between the steering and rating groups, the finalized question and answer sets were submitted for final review by the peer review group composed of representatives of the ESSKA-affiliated national societies. Eighteen representatives replied. RESULTS: The review of the literature revealed a rather low scientific quality of studies examining the treatment of traumatic meniscus tears. Of the 27 questions, only one question received a grade of A (a high level of scientific support), and another received a grade of B (scientific presumption). The remaining questions received grades of C and D. The mean rating of all questions by the rating group was 8.2 (95% confidence interval 8.1-8.4). A general agreement that MRI should be performed on a systematic basis was not achieved. However, MRI was recommended when arthroscopy would be considered to identify concomitant pathologies. In this case, the indication for MRI should be determined by a musculoskeletal specialist. Based on our data, stable left in situ lateral meniscus tears appear to show a better prognosis than medial tears. When repair is required, surgery should be performed as early as possible. Evidence that biological enhancement such as needling or the application of platelet-rich plasma would improve healing was not identified. Preservation of the meniscus should be considered as the first line of treatment because of an inferior clinical and radiological long-term outcome after partial meniscectomy compared to meniscus repair. DISCUSSION: The consensus was generated to present the best possible recommendations for the treatment of traumatic meniscus tears and provides some groundwork for a clinical decision-making process regarding the treatment of meniscus tears. Preservation of the meniscus should be the first line of treatment when possible, because the clinical and radiological long-term outcomes are worse after partial meniscectomy than after meniscus preservation. The consensus clearly states that numerous meniscus tears that were considered irreparable should be repaired, e.g., older tears, tears in obese patients, long tears, etc. LEVEL OF EVIDENCE: II.

Correction to: Rotational profile alterations after anatomic posterolateral corner reconstructions in multiligament injured knees.

The original article can be found online.

Torsional Appearance of the Anterior Cruciate Ligament Explaining "Ribbon" and Double-Bundle Concepts: A Cadaver-based Study.

PURPOSE: To investigate the effect of the anterior cruciate ligament (ACL) torsion in 90° knee flexion on the morphological appearance of the ACL. METHODS: Sixty knees from fresh frozen anatomical specimens were dissected. Eighteen knees were excluded according to selection criteria (torn ACL, mucoid degeneration of the ACL, arthritic lesions of the notch, or knees harboring synovial inflammatory pathologies). After the removal of the synovial membrane, the morphology of the ligamentous fibers of the ACL and the twist were analyzed. Twisting of the ACL was measured using a goniometer in 90° knee flexion and defined by the angle of external rotation of the femur on the axis of the tibia required to visualize a flat ACL. The orientation of tibial and femoral footprint was described in a coronal plane for the tibia and a sagittal plane for the femur. RESULTS: In the 42 knees that were finally included, the ACL was always displayed as a single ribbon-like structure. The torsion of the fibers was on average 83.6° (± 9.4°) in 90° knee flexion. The twisting could be explained by the different orientations of the femoral (vertical in a sagittal plane) and tibial (horizontal in a coronal plane) footprints. An intraligamentous proximal cleavage area was encountered in 11 cases (i.e., 26%). CONCLUSIONS: The ACL is a twisted structure with 83.6° of external torsion of fibers in 90° knee flexion. It is the torsion in the fibers, due to the relative position of bone insertions, which gives the ACL the appearance of being double bundle. CLINICAL RELEVANCE: The concept of the torsional flat structure of the native ACL may be of importance during ACL reconstruction, both in terms of graft choice (flat rather than cylindrical) and of technical positioning (torsion).

Bone mineral density of the coracoid process decreases with age.

PURPOSE: Surgical options in the treatment of recurrent anterior shoulder instability are numerous. The Latarjet procedure is one of the most common procedures performed. It has been previously demonstrated that bone mineral density decreases with age. This reduction thus increases the risk of osteoporosis and osteoporosis-related iatrogenic, traumatic or pathological fractures. The objective of this study was to quantify the bone mineral density of the coracoid process in different age groups. The hypothesis was that mineral bone density of the coracoid process decreases with age. METHODS: Using the hospital's electronic database, 60 patients who underwent a shoulder CT scan were randomly selected retrospectively. Four groups of 15 were formed with mean ages of 20, 30, 40 and 50 years. Bone density, length, width and thickness of the coracoid process 10 mm from the tip were measured four times by two different evaluators. Bone density was expressed in Hounsfield units (HU). RESULTS: The mean bone mineral density of the coracoid process significantly decreased with age (p < 0.0001). A lower but insignificant difference of bone mineral density was observed in females. A good inter- and intra-observer reliability was found for bone mineral density measurement of the coracoid process (0.67 and 0.7, respectively). CONCLUSIONS: The bone mineral density of the coracoid process diminishes with age, thus confirming our hypothesis. There is a good inter- and intra-observer reliability of our CT scan-based coracoid process bone mineral density measurement rendering it reproducible in daily clinical practice. LEVEL OF EVIDENCE: IV.

Platelet-rich plasma for open meniscal repair in young patients: any benefit?

PURPOSE: Many studies have demonstrated that injection of various growth factors including platelet-derived growth factor could increase meniscal cell activity and stimulate repair. The purpose of this study was to augment repair and promote meniscal healing by the use of platelet-rich plasma (PRP) within horizontal cleavage meniscal tears repaired via an open approach. The hypothesis was that the clinical outcomes and healing process would be improved using this meniscal healing augmentation technique. METHODS: In this case-control study, 34 consecutive young patients underwent an open meniscal repair to treat symptomatic Grade 2 or Grade 3 horizontal meniscal tears [median age 28 years (13-40)]. The median time between the onset of symptoms and surgery was 11.5 months (6-50). In the first group (17 consecutive patients, Group 1), a standard open meniscal repair was performed. In the second group (17 consecutive patients, Group 2), the same surgical repair was performed, but platelet-rich plasma was introduced into the lesion at the end of the procedure. Clinical outcomes were evaluated using KOOS and IKDC 2000 scores. MRI was performed at 1 year after surgery for objective evaluation. RESULTS: At a minimum of 24 months postoperatively (mean 32.2 months, 24-40), three patients underwent subsequent meniscectomy (two in Group 1, one in Group 2). The mean KOOS distribution (pain, symptoms, daily activities, sports, quality of life) was 78.4, 86.1, 93.8, 74.4, 74.6 in Group 1, and 93.3, 90.7, 97.1, 88.8, 78.3 in Group 2 (p < 0.05 for pain and sports parameters). MRI revealed five cases with the complete disappearance of any hypersignal within the repaired meniscus in Group 2, and none in Group 1 (p < 0.01). CONCLUSIONS: Open meniscal repair of horizontal tears extending into the avascular zone was effective at midterm follow-up in young patients. Clinical outcomes were slightly improved by the addition of PRP in this case-control study. LEVEL OF EVIDENCE: III.

Long-term outcomes of all-inside meniscal repair.

PURPOSE: The mean reported healing rate after meniscal repair is 60% of complete healing, 25% of partial healing and 15% of failure. However, partially or incompletely healed menisci are often asymptomatic in the short term. It is unknown whether the function of the knee with a partially or incompletely healed meniscus is disturbed in the long term. The purpose of this study was to assess the long-term outcomes of meniscal repairs according to the initial rate of healing. METHODS: Forty-one consecutive meniscal repairs were performed between 2002 and 2003. The median age at the time of surgery was 22 years (9-40). There were 25 medial and 16 lateral menisci. When present, all ACL lesions underwent reconstruction (61.3% of cases). According to Henning's criteria, by Arthro-CT at 6 months, twenty cases had healed completely, seven partially healed and four cases healed incompletely. RESULTS: At a mean follow-up of 114 ± 10 months, 31 patients were retrospectively followed for clinical and imaging assessments. Objective IKDC score was good in 92% of the cases (17 IKDC A, 8 B and 2 C). The mean KOOS distribution was as follows: pain 94.3 ± 9; symptoms 90.9 ± 15; daily activities 98.7 ± 2; sports activities 91.1 ± 14; and quality of life 91.5 ± 15. Twenty-three patients displayed no signs of osteoarthritis when compared to the non-injured knee, six patients had grade 1 osteoarthritis and two grade 2. The subjective IKDC score did not decrease with time (ns). Moreover, there were no differences between lateral and medial menisci (ns), in stable or stabilised knees (ns). The initial meniscal healing rate did not significantly influence clinical or imaging outcomes (ns). Four patients with no healing underwent a meniscectomy (12.9%). CONCLUSION: Arthroscopic all-inside meniscal repair with hybrid devices may provide long-term protective effects, even if the initial healing is incomplete. LEVEL OF EVIDENCE: Case series, Level IV.

Clinical and radiographic results of arthroscopic partial lateral meniscectomies in stable knees with a minimum follow up of 20 years.

PURPOSE: The purpose of this retrospective multicentric study was to evaluate the long-term effects of lateral meniscectomy and to identify those patients who are at the most risk of developing osteoarthritis (OA). METHODS: Eighty-nine arthroscopic partial lateral meniscectomies in stable knees with a mean follow-up of 22 ± 3 years were included. The following influencing factors were analyzed: age, sex, body mass index (BMI), physical activity, alignment, the types of meniscal lesions, the extent of meniscal resections and the initially associated cartilage lesions. An independent examiner reviewed all patients, using subjective (KOOS and IKDC scores) and objective clinical and radiological evaluations (IKDC score). The contralateral knee was used as a reference to calculate the prevalence and the incidence of OA. RESULTS: The mean age at the time of surgery was 35 ± 13 years. The main location of the lesions was the mid-section of the lateral meniscus (79% of the cases). At the latest follow-up, 48% of the patients had an active lifestyle with as many as 48% of the patients enjoying moderate to intense physical activity 22 years after the procedure (vs. 71% before surgery). The KOOS score evolved from 82 to 69% during the same period. The prevalence of OA was 56% in the affected knee and the difference of prevalence between the operated and healthy knees was 44%. In those patients presenting with an OA of the operated knee and a normal contralateral knee, the incidence of OA was 53%. Predictors of OA were an age superior to 38 years at the time of surgery, obesity (BMI >30), and valgus malalignment as well as the presence of cartilage and degenerative meniscal lesions at the time of surgery. CONCLUSION: In the long term, arthroscopic partial lateral meniscectomy in stable knees without initial cartilage lesions might yield good to excellent results in young patients. Patients are at higher risk to develop symptomatic OA if they are over 40, having a high BMI, valgus malalignment and cartilage lesions at the time of surgery. This study provides precise guidelines for the surgical treatment of lateral meniscus tears. LEVEL OF EVIDENCE: IV.

Rotational profile alterations after anatomic posterolateral corner reconstructions in multiligament injured knees.

PURPOSE: Injuries of the posterolateral corner (PLC) are rare and severe knee injuries, resulting in posterolateral rotatory instability and an increase in external rotation. Surgical reconstruction techniques reproducing the normal anatomy showed promising results. In vivo evaluations of static rotational knee laxity at 30° of knee flexion have not been reported so far. The purpose of this study was to evaluate static rotational knee laxity after anatomic PLC reconstructions. METHODS: This is a retrospective clinical cohort study. Twenty patients with PLC reconstructions with an average follow-up time of 39 ± 22 months and no history of knee trauma or surgery of the contralateral knee were included in the study. They underwent a routine clinical examination and static rotational laxity measurements at 30° of knee flexion in the prone position. Side-to-side differences were recorded and compared to a group of matched controls. RESULTS: The postoperative IKDC score was graded A for 8 patients, B for 16, C for 6 and D for one patient. The primary goal of the surgical procedure which consists in reducing excessive external tibiofemoral rotation could be reached in 18 of the 20 patients (90%). Anatomic PLC reconstructions yielded a comparable rotational profile in operated and healthy knees in 7 patients (35%). Thirteen patients (65%) presented a significantly altered rotational profile in comparison with a healthy control group. Unexpected increases in internal rotation were found in 8 patients (40%). CONCLUSION: Anatomic PLC reconstructions reduced excessive external tibiofemoral rotation in a vast majority of patients. Static rotational laxity measurements allowed for a determination of the patients' individual rotational profile after PLC reconstructions. This profile was normalised in only one-third of the patients. The understanding of this finding needs further investigation as well as the clinical impact of rotational profile alterations on knee function. LEVEL OF EVIDENCE: Diagnostic studies, Level III.