Position Statement From the Australian Knee Society on Arthroscopic Surgery of the Knee, Including Reference to the Presence of Osteoarthritis or Degenerative Joint Disease: Updated October 2016.

Arthroscopic debridement and/or lavage has been shown to have no beneficial effect on the natural history of osteoarthritis (OA), nor is it indicated as a primary treatment in the management of OA. However, this does not preclude the judicious use of arthroscopic surgery, when indicated, to manage symptomatic coexisting abnormalities in the presence of OA or degeneration. Partial medial meniscectomy is not indicated as an initial treatment for atraumatic tears of degenerative menisci, excluding bucket-handle tears and surgeon-assessed locked or locking knees.

Arthroscopic Surgery in the Presence of Osteoarthritis or Degeneration

There are certain clinical scenarios in which arthroscopic surgery, in the presence of OA, may be appropriate. These include, but are not necessarily limited to, the following:

known or suspected septic arthritis;

symptomatic nonrepairable meniscal tears after the failure of an appropriate trial of a structured rehabilitation program;

symptomatic loose bodies;

surgeon-assessed locked or locking knees;

traumatic or atraumatic meniscal tears that require repair;

inflammatory arthropathy requiring synovectomy;

synovial abnormalities requiring biopsy or resection;

large unstable chondral abnormalities causing surgeon-assessed locking or locked knees;

as an adjunct to, and in combination with, other surgical procedures as appropriate for OA (eg, high tibial osteotomy and patellofemoral realignment); and

diagnostic arthroscopic surgery when the diagnosis is unclear on magnetic resonance imaging (MRI) or MRI is not possible and the symptoms are not of OA.

The decision to proceed with arthroscopic surgery in the presence of OA or degeneration should be made by the treating orthopaedic surgeon:

after a careful review of the clinical scenario, particularly the assessment of the relative contributions of OA and the arthroscopically treatable abnormality, to the patient’s symptoms;

with knowledge of the relevant evidence base, as listed in this work;

after an appropriate trial of structured rehabilitation; and

after a thoughtful discussion with the patient about the relative merits of the procedure versus ongoing nonoperative treatment.

Definitions

OA, or degenerative joint disease, is a progressive clinical disorder of joints characterized by gradual diffuse loss of articular cartilage, effects on the underlying bone, and secondary compromise of joint function. This should be distinguished from focal articular cartilage abnormalities in an otherwise normal joint.

There is a spectrum of severity of OA from minor partial-thickness articular cartilage abnormalities to large areas of full-thickness loss. Clinical decision making requires a careful assessment of the degree of arthritis, its likely contribution to the symptoms, and the potential contribution of additional abnormalities to those symptoms.

The concept of degenerative versus traumatic, in regard to meniscal lesions and tearing, is arbitrary.[15] No universally accepted definition of degeneration or degenerative change exists, and commonly used clinical diagnostic descriptors lack validity.

Assessment and Interpretation of MRI

While plain radiography is the preferred initial imaging modality, MRI remains an excellent adjunct both to clinical decision making and to guiding the use of surgery. In particular, it can be used to more accurately assess the degree of arthritis and to look for and assess additional abnormalities that may correlate with a patient’s symptoms. MRI scans should be interpreted carefully by the treating surgeon, in combination with direct review of the imaging, when determining the clinical relevance of the findings. MRI descriptions of meniscal tearing, degeneration, and lesions in the absence of trauma lack validity. Further information on the appropriate radiological investigation of knee OA can be obtained from the statement, “Joint AKS-AMSIG Submission to the Australian Commission on Quality and Safety in Healthcare on the Radiological Investigation of Knee Osteoarthritis” (http://www.kneesociety.org.au/resources/Joint-AKS-AMSIG-submission-ACQSH-investigation-knee-osteoarthritis.pdf).

Systematic Review: Arthroscopic Surgery in the Presence of Osteoarthritis

Introduction

Our aim was to examine the evidence of effectiveness, inclusion and exclusion criteria, effects of age, and adverse events in existing knee arthroscopic surgery randomized controlled trials (RCTs), with a view to the formulation of clinical indication guidelines based on International Classification of Diseases–10th Revision (ICD-10) codes for knee arthroscopic surgery in the presence of degeneration or OA.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement for systematic reviews was utilized for this work.[11]

Literature Search and Study Selection

In December 2015, a systematic search for clinical indications in Medline, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials was undertaken. The keywords “arthroscopy” and “knee,” or variations of them, were used. Limitations to clinical trials and human studies were applied. No search restrictions for follow-up time, study size, or date of publication were set.

Eligibility Criteria

The inclusion and exclusion criteria were as follows.

Inclusion criteria:

RCTs assessing the effectiveness of arthroscopic surgery involving meniscal surgery, debridement, chondroplasty, loose body removal, or any combinations, with or without clinical or radiographic OA, compared with nonoperative treatment, sham surgery, or lavage.

English-language reports.

Publication in a peer-reviewed journal.

Exclusion criteria:

All criteria for inclusion had to be satisfied, and other systematic reviews or meta-analyses were excluded.

Data Extraction

Titles and/or abstracts of studies that were retrieved using the search strategy were screened independently by 2 review authors to identify studies that potentially met the inclusion criteria. The full-text versions of these potentially eligible studies were retrieved and independently assessed for eligibility by the 2 review team members. Any disagreement over the eligibility of a particular study was resolved through consensus with the addition of a third reviewer.

A standardized form was used to extract data from the included studies for the assessment of study quality and evidence synthesis. Extracted information included study population, primary diagnosis, inclusion criteria, exclusion criteria, details of the intervention, details of the comparator, study methodology, outcomes and times of measurement, and power analysis. Two review authors extracted the data independently.

If 2 separate studies with the same authors and the same intervention had overlapping dates of patient enrollment, then only 1 study was included. In this situation, the reviewer selected the study with the longer follow-up. If a different data analysis or subanalysis was undertaken, then the supplemental study was included.

ICD-10 Diagnosis Matching

ICD-10–Clinical Modification (ICD-10-CM) codes or ICD-10–Procedure Coding System (ICD-10-PCS) codes were matched by 2 review authors to the inclusion and exclusion criteria of all matched studies. ICD-10-CM codes were developed by the United States Centers for Disease Control and Prevention in conjunction with the National Center for Health Statistics for outpatient medical coding and reporting, as published by the World Health Organization. ICD-10-PCS codes were developed by the United States Centers for Medicare and Medicaid Services as a system of procedural codes to classify all health interventions by medical professionals.[1]

Results

Knee Arthroscopic Surgery Outcome Studies

Fourteen RCTs of arthroscopic knee surgery (Table 1) fulfilled the search criteria (Figure 1) in 3 different primary clinical ICD-10 diagnosis categories (Table 2). In 4 studies, the primary clinical diagnosis was OA[2,9,10,12] (ICD-10 code M17.9). In the study by Hubbard,[6] the primary clinical diagnosis was a single medial femoral condyle degenerative chondral lesion; however, not enough information was provided by the author to allow the classification of the degenerative chondral lesion as clinical OA.

TABLE 1

Arthroscopic Surgery Outcomes in Randomized Controlled Trials

Author (Year)	Primary Diagnosis	Intervention	Inclusion Criteria	Mode of Investigation	No. of Patients	Control	Not Enrolled, %	OA Rating on Radiographs	Joint-Specific Exclusion Criteria	Crossover, %	Power Analysis	Notes	Outcomes
OA studies
Merchan  and  Galindo[10]  (1993)	Mild OA with other intra-articular abnormalities	Synovectomy, debridement, APM, chondroplasty, excision of osteophytes, PT	Painful “limited” OA, including patients with meniscal tears, loose bodies, and synovitis	Radiographs	73	Nonsteroidal anti- inflammatory drugs, activity modification	NS	Ahlbach grade 0-1, KL grade 1-2	Duration of pain >6 mo, body weight >85 kg in men and >70 kg in women, previous surgery, instability or an angular deformity >15°, patellofemoral OA	NS	No	OM = modified Hospital for Special Surgery knee score; APM performed in 31/35; power >0.8	Favored AS at 1-3 y (mean, 25 mo)
Chang  et al[2]  (1993)	OA	APM, chondroplasty, synovectomy	Pain at 3 mo after rehabilitation	Radiographs	32	Needle lavage	50	KL grade 1-3	Prior knee surgery within 6 mo, TKA, OA (KL grade 4)	NS	No	Inadequate power; 50% had KL grade 3	No difference at 12 mo
Hubbard[6]  (1996)	Symptomatic single medial femoral condyle degenerative chondral lesion (Outerbridge grade 3 or 4)	Chondroplasty, no APM	Symptoms >1 y, no laxity or no deformity, full ROM, single medial femoral condyle degenerative lesion (Outerbridge grade 3 or 4), no other intra-articular abnormality, normal plain radiograph findings, modified Lysholm score <38/70	Radiographs	76	Arthroscopic lavage	NS	KL grade 0	Degenerative lesions on other joint surfaces, other intra-articular abnormality, radiographic loss of joint space, previous surgery, steroid injection for any reason, MMT or tibial degeneration	NS	No	OM = binary self-described pain (presence/absence) and modified Lysholm score; power >0.8	Favored AS at 1 and 5 y
Moseley  et al[12]  (2002)	Tricompartmental OA	APM, chondroplasty	Age <75 y, moderate knee pain that failed 6 mo of medical management with VAS pain score >3, diagnosis of OA based on ACR classification	Radiographs	180	Sham surgery or lavage	44	KL grade 3-4	Scoring >9 by KL grade in 3 compartments	NS	Yes	3-arm study; in lavage group, “mechanically important, unstable tears” were debrided; in sham group, joint not entered; OM = bespoke knee-specific pain scale, Arthritis Impact Measurement Scales–2, and SF-36	No difference at 2 y between 3 groups
Kirkley  et al[9]  (2008)	Symptomatic moderate to severe OA	Synovectomy, debridement, APM, chondro plasty, excision of osteophytes, PT	Age >18 y with idiopathic or secondary OA (KL grade 2-4)	Radiographs and MRI	188	PT	16	KL grade 0-4	Large meniscal tears, bucket-handle tears, prior major knee trauma, inflammatory or postinfectious arthritis, deformity >5°, KL grade 4 in 2 compartments	0	Yes	OM = WOMAC and SF-36	No difference at 2 y
MMT studies
Yim et al[18]  (2013)	Symptomatic horizontal degenerative MMT	APM, PT	Horizontal degenerative MMT on MRI, daily knee pain on medial side with mechanical symptoms, failed nonoperative management	MRI	108	PT	30	KL grade 0-1	Definite trauma, ligament deficiency, systemic arthritis, KL grade 2-4, osteonecrosis, meniscal repair, abrasion arthroplasty, subchondral drilling, curettage	2	Yes	No meniscal repair or total meniscectomy undertaken; OM = VAS, Lysholm score, and Tegner score	Favored AS at 3 mo; no difference at 2 y; meniscal tear pattern described
Sihvonen  et al[15]  (2013)	Symptomatic degenerative MMT confirmed on MRI and AS	APM, PT	Age 35-65 y, knee pain >3 mo that was unresponsive to conventional conservative treatment, clinical findings consistent with an MMT	Radiographs and MRI	146	Sham surgery, PT	12	KL grade 0-1	Trauma-induced onset of symptoms; locked or recently locking knee; decreased ROM; instability; abnormality other than degenerative knee disease requiring treatment other than APM, meniscal repair, and microfracture to chondral defect; major chondral flap; clinical OA based on ACR classification; KL grade >1	6.6	Yes	No chondroplasty undertaken; OM = VAS, Lysholm score, and WOMET; blinded study; meniscal tear pattern not described	No difference at 12 mo; “results are directly applicable only to patients with nontraumatic degenerative medial meniscus tears”
Katz et al[7]  (2013)	Symptomatic degenerative MMT with mild to moderate OA	APM, chondroplasty, PT	Age >45 y; >1 mo of symptoms; imaging evidence of mild to moderate knee OA; symptoms of the following: clicking, catching, popping, giving way, pain with pivot or torque, pain that is episodic, pain that is acute and localized to one joint line), KL grade 0-3	Radiographs and MRI	330	PT	75	KL grade 0-3	Chronically locked knee, KL grade 4, clinically symptomatic chondrocalcinosis, bilateral symptomatic meniscal tears, prior surgery on same knee	30.2	Yes	Similar improvement in WOMAC score in failed PT once crossed over to APM; treatment success defined as >8-point improvement on WOMAC physical function scale; meniscal tear pattern not described	No difference at 12 mo; 30% crossed over to APM; treatment failure of 25% in APM group and 49% in PT group; same adverse events between groups
Herrlin  et al[5]  (2013)	MRI-verified degenerative MMT and radiographic OA (Ahlback grade <2)	APM, chondroplasty, PT	Age 45-60 y, daily medial pain over 2-6 mo	Radiographs and MRI	96	PT	55	Ahlback grade 1, Outerbridge grade 1-4	History of trauma, OA of Ahlback grade >1, rheumatoid arthritis, loose bodies, knee instability, osteochondral defects and tumors, TKA, prior knee surgery in past year	33	Yes	No difference in OA progression noted between 2 groups; OM = KOOS, Lysholm score, and VAS; similar PROM improvements in PT and APM; meniscal tear pattern not described	No difference at 2 and 5 y; 33% of PT group crossed over to APM with similar benefit to APM group and rest of PT group at 2 and 5 y; this subgroup had significantly lower PROM scores than rest of PT group before APM
Vermesan  et al[17]  (2013)	MRI-verified degenerative MMT and radiographic OA	APM, chondroplasty, PT	Nontraumatic symptomatic knees with degenerative lesions in medial compartment on MRI	MRI	120	Corticosteroid injection	NS	NS	NS	NS	No	OM = Oxford Knee Score; post hoc power analysis >0.8 (d = 0.3; 2-tailed, P = .05); meniscal tear pattern not described	Better scores in surgical group at 3 mo; no difference at 12 mo
Østerås  et al[13]  (2012)	MRI-verified degenerative MMT and radiographic OA	APM	Age 35-60 y	MRI	17	PT	12	KL grade 0-2	Anterior cruciate ligament tears, acute trauma, KL grade 3-4, hemarthrosis, locking knee	0	Yes	Inadequate power based on authors’ own power analysis; OM = VAS and KOOS	No difference at 3 mo; meniscal tear pattern not described
Gauffin  et al[4]  (2014)	Symptomatic MMT	APM, chondro plasty	Age 45-64 y, symptoms of MMT >3 mo (Ahlback grade 0), prior PT	Radiographs	150	PT	2.8	Ahlbach grade 0, KL grade 1-2	Locked/locking knee, rheumatic disease	21.3	Yes	OM = KOOS, EuroQol 5-Dimensions Questionnaire, Physical Activity Scale, and symptom satisfaction scale; meniscal tear pattern not described	Favored AS at 12 mo
Sihvonen  et al[14]  (2016)	Symptomatic degenerative MMT confirmed on MRI and AS; subgroup analysis of original Sihvonen et al[15] (2013) study of patients with mechanical symptoms	APM, PT	Age 35-65 y, knee pain >3 mo that was unresponsive to conventional conservative treatment, clinical findings consistent with an MMT with mechanical symptoms	Radiographs and MRI	69	Sham surgery, PT	NS	KL grade 0-1	Trauma-induced onset of symptoms; locked or recently locking knee; decreased ROM; instability; abnormality other than degenerative knee disease requiring treatment other than APM, meniscal repair, and microfracture to chondral defect; meniscal repair; major chondral flap; clinical OA based on ACR classification; KL grade >1	2.5	No	No chondroplasty undertaken; OM = VAS, Lysholm score, and WOMET; blinded study; meniscal tear pattern not described	No difference at 12 mo; “this subgroup analysis is likely to be underpowered”; post hoc analyses: study questions were not included a priori as primary or secondary objectives of original trial
Patellofemoral pain study
Kettunen  et al[8]  (2012)	Patellofemoral pain and symptoms lasting at least 6 mo	Chondroplasty	Age 18-40 y; female or male; symptoms lasting at least 6 mo; patellofemoral pain during knee loading, physical activity, or prolonged flexion	NS	56	PT	2	KL grade 0	Prior knee surgery, patellar dislocation, osteochondritis dissecans, patellar tendinopathy, OA, loose bodies, instability	10	Yes	OM = Kujala score and VAS	No difference at 2 and 5 y

ACR, American College of Rheumatology; APM, arthroscopic partial meniscectomy; AS, arthroscopic surgery; KL, Kellgren-Lawrence; KOOS, Knee Injury and Osteoarthritis Outcome Score; MMT, medial meniscal tear; MRI, magnetic resonance imaging; NS, not stated; OA, osteoarthritis; OM, outcome measure; PROM, patient-reported outcome measure; PT, physical therapy; ROM, range of motion; SF-36, Short Form–36; TKA, total knee arthroplasty; VAS, visual analog scale; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index; WOMET, Western Ontario Meniscal Evaluation Tool.

Figure 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram.

TABLE 2

Inclusion and Exclusion Criteria in Arthroscopic Knee Surgery RCTs Using ICD-10 Codes

Clinical diagnoses included in RCTs

Unilateral osteoarthritis of knee[2,4,10]

M17.9: Osteoarthritis of knee, unspecified

M17.0: Bilateral primary osteoarthritis of knee

M17.1: Unilateral primary osteoarthritis of knee

Atraumatic degenerative tears to medial meniscus[5,14–17]

M23.2: Derangement of meniscus due to old tear or injury

M23.22: Derangement of posterior horn of medial meniscus due to old tear or injury

M23.30: Other meniscus derangements, unspecified meniscus

M23.32: Other meniscus derangements, posterior horn of medial meniscus

Patellofemoral chondropathy[13]

M22.4: Chondromalacia patella

Clinical diagnoses excluded from RCTs b

Locking or locked knee[5,10,14,15]

M23.40: Loose body in knee[13,16]

M21.26: Flexion deformity, knee

M93.2: Osteochondritis dissecans

M23.8: Other internal derangements of knee

S83.21A: Bucket-handle tear of medial meniscus, current injury, initial encounter[10]

S83.205A: Other tear of unspecified meniscus, current injury, unspecified knee, initial encounter

S83.22A: Peripheral tear of medial meniscus, current injury, initial encounter

S83.26A: Peripheral tear of lateral meniscus, current injury, initial encounter

M25.669: Stiffness of unspecified knee, not elsewhere classified

Knee instability[13,15–17]

M23.60: Other spontaneous disruption of unspecified ligament of knee

M23.61: Other spontaneous disruption of anterior cruciate ligament of knee

M23.62: Other spontaneous disruption of posterior cruciate ligament of knee

Internal derangements other than medial meniscal tear[15,16]

M93.2: Osteochondritis dissecans

M23.8: Other internal derangements of knee

M23.25: Derangement of posterior horn of lateral meniscus due to old tear or injury

M23.26: Derangement of other lateral meniscus due to old tear or injury

M23.35: Other meniscus derangements, posterior horn of lateral meniscus

M23.23: Derangement of other medial meniscus due to old tear or injury

M87.88: Osteonecrosis

Meniscal cysts[15]

M23.0: Cystic meniscus

Nonosteoarthritic arthropathies[2,4,5,10,14,15,17]

M00.06: Staphylococcal arthritis, knee

M00.86: Arthritis due to other bacteria, knee

M02.86: Other reactive arthropathies, knee

M02.36: Reiter disease, knee

M05.76: Rheumatoid arthritis of knee

M10.06: Idiopathic gout, knee

M11.06: Hydroxyapatite deposition disease, knee

M12.26: Villonodular synovitis (pigmented), knee

Traumatic meniscal injury[10,15–17]

S83.2: Tear of meniscus, current injury

S83.21A: Bucket-handle tear of medial meniscus, current injury, initial encounter

S83.205A: Other tear of unspecified meniscus, current injury, unspecified knee, initial encounter

S83.22A: Peripheral tear of medial meniscus, current injury, initial encounter

S83.23A: Complex tear of medial meniscus, current injury, initial encounter

S83.24A: Other tear of medial meniscus, current injury, initial encounter

S83.25A: Bucket-handle tear of lateral meniscus, current injury

S83.26A: Peripheral tear of lateral meniscus, current injury, initial encounter

S83.27A: Complex tear of lateral meniscus, current injury, initial encounter

S83.28A: Other tear of lateral meniscus, current injury, initial encounter

Traumatic or secondary osteoarthritis of knee[10]

M17.2: Bilateral posttraumatic osteoarthritis of knee

M17.3: Unilateral posttraumatic osteoarthritis of knee

M17.4: Other bilateral secondary osteoarthritis of knee

M17.5: Other unilateral secondary osteoarthritis of knee

Meniscal repair[15,17]

0SQC4ZZ: Repair right knee joint, percutaneous endoscopic approach

0SQD4ZZ: Repair left knee joint, percutaneous endoscopic approach

Osteoarthritis as defined by the American College of Rheumatology. ICD-10, International Classification of Diseases–10th Revision; RCT, randomized controlled trial.

Does not include nontraumatic osteoarthritis in studies with a primary clinical diagnosis other than osteoarthritis. Diagnoses of conditions external to the knee joint not included.

In 8 studies, the primary clinical diagnosis was a symptomatic degenerative atraumatic medial meniscal tear (MMT)[4,5,7,13-15,17,18] (ICD-10 code M23.2) in the presence of chondral degeneration of various degrees. In the study by Kettunen et al,[8] the primary clinical diagnosis was patellofemoral pain (ICD-10 code M22.4).

Three RCTs were assessed as having inadequate power for the primary outcome measure. Østerås et al[13] examined arthroscopic partial medial meniscectomy in the presence of knee OA compared to physical therapy. They included a power analysis; however, the final number of patients in their study was less than stated to achieve adequate power. Chang et al[2] lacked a power analysis; however, a post hoc power analysis using G*Power[3] revealed that the study was inadequately powered (power <0.8) to confirm the self-described meaningful improvement of a reduction of >1 cm from the baseline visual analog scale score. Sihvonen et al[14] provided a post hoc subgroup analysis of patients from their original 2013 RCT[15] who suffered self-described mechanical symptoms, defined as catching and clicking excluding locked or recently locked knees. The authors stated that the subgroup analysis was underpowered.

Three studies favored an arthroscopic intervention at final follow-up: 2 OA studies[6,10] and 1 MMT study.[4] The remaining 11 studies reported no outcome difference compared to the control intervention.

Risk of Bias Assessment

Studies were rated for their risk of bias in Table 3. There were no studies with a low risk of bias in all 7 risk domains assessed in the OA studies and patellofemoral pain studies.[10] In the MMT studies, there was only 1 study with a low risk of bias[15] in all domains.

TABLE 3

Risk of Bias Assessment

	Random Sequence Generation	Allocation Concealment	Blinding of Participants	Blinding of Outcome Assessment	Incomplete Outcome Data	Selective Reporting	Other Bias
Merchan and Galindo[10] (1993)	Low risk	Unclear	High risk	High risk	Low risk	Low risk	Low risk
Chang et al[2] (1993)	Unclear	Unclear	High risk	High risk	Unclear	Low risk	Low risk
Hubbard[6] (1996)	Low risk	Low risk	High risk	High risk	Unclear	Unclear	Low risk
Moseley et al[12] (2002)	Unclear	Low risk	Low risk	Low risk	High risk	Low risk	Low risk
Kirkley et al[9] (2008)	Low risk	Unclear	High risk	High risk	Unclear	Low risk	Low risk
Yim et al[18] (2013)	Unclear	Low risk	High risk	High risk	High risk	Low risk	Low risk
Sihvonen et al[15] (2013)	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk	Low risk
Gauffin et al[4] (2014)	Unclear	Low risk	High risk	High risk	Low risk	Low risk	Low risk
Katz et al[7] (2013)	Low risk	Low risk	High risk	High risk	Low risk	Low risk	Low risk
Herrlin et al[5] (2013)	Unclear	Unclear	High risk	High risk	Low risk	Low risk	Low risk
Vermesan et al[17] (2013)	Unclear	Unclear	High risk	High risk	Unclear	Unclear	Low risk
Kettunen et al[8] (2012)	Low risk	Low risk	High risk	High risk	Unclear	Low risk	Low risk
Østerås et al[13] (2012)	Unclear	Unclear	High risk	High risk	Low risk	Unclear	Low risk
Sihvonen et al[14] (2016)	Low risk	Low risk	Low risk	Low risk	Low risk	High risk	Low risk

Exclusion Criteria in MMT Studies

In the 8 studies with a primary clinical diagnosis of an MMT, 5 studies excluded surgeon-assessed locked or locking knees,[4,7,13-15] and 1 study excluded loose bodies,[5] with Vermesan et al[17] not stating any exclusion criteria (Table 4). The Sihvonen et al[15] (2003) and Sihvonen et al[14] (2016) studies excluded surgeon-assessed locked or recently locked knees and major chondral flaps but included knees with patient-reported catching and locking symptoms. Yim et al[18] and Katz et al[7] also included patients with mechanical symptoms.

TABLE 4

Exclusion Criteria in Medial Meniscal Tear Randomized Controlled Trials

	Locking or Locked Knee	History of Trauma	Meniscal Repair	Loose Bodies	Major Chondral Flap	Other Nonmeniscal Abnormality
Yim et al[18] (2013)	NS	Yes	Yes	NS	NS	Yes
Sihvonen et al[15] (2013)	Yes	Yes	Yes	NS	Yes	Yes
Gauffin et al[4] (2014)	Yes	NS	NS	NS	NS	Yes
Katz et al[7] (2013)	Yes	NS	NS	NS	NS	Yes
Herrlin et al[5] (2013)	Yes	Yes	NS	Yes	NS	Yes
Vermesan et al[17] (2013)	NS	NS	NS	NS	NS	Yes
Østerås et al[13] (2012)	Yes	Yes	NS	NS	NS	Yes
Sihvonen et al[14] (2016)	Yes	Yes	Yes	NS	Yes	Yes

NS, not stated.

A history of traumatic onset was an exclusion criterion in 6 MMT studies,[5,13-15,17,18] with Vermesan et al[17] not stating any exclusion criteria. No study included meniscal repair as a management intervention, and meniscal repair was an exclusion criterion in 3 studies.[14,15,18]

No study included diagnostic arthroscopic surgery. Inflammatory joint disorders were excluded in 4 studies[9,14,15,18] or were not an inclusion criterion in the remainder.

Exclusion Criteria in OA Studies

Merchan and Galindo[10] excluded patients with pain longer than 6 months, male patients with a weight over 85 kg, female patients weighing greater than 70 kg, instability, or an angular deformity greater than 15°. Hubbard[6] excluded any other intra-articular lesions except for symptomatic medial femoral condyle degenerative lesions in patients with no radiographic OA. Moseley et al[12] added the Kellgren-Lawrence grade for each compartment together, excluding the patients with a score of greater than 9. Kirkley et al[9] excluded patients with large meniscal tears, bucket-handle tears, prior major knee trauma, inflammatory or postinfectious arthritis, deformity >5°, or Kellgren-Lawrence grade 4 in 2 compartments.

Types of MMTs

Only the study by Yim et al[18] described the MMT pattern; the remainder grouped all MMT patterns together as atraumatic degenerative. Sihvonen et al[15] described an atraumatic sudden symptom–onset subgroup that did no better with a surgical intervention.

Crossover Into Surgical Group

None of the OA studies described crossover into the surgical group. Seven of the 9 MMT studies described crossover into the surgical group of 0%,[13] 2%,[18] 2.5%,[14] 6.6%,[15] 21.3%,[4] 30.2%,[7] and 33.3%.[5] Reasons for crossover into the surgical group were either those of persistent symptoms[4,5,15] or were not given.[7,18] Herrlin et al[5] and Katz et al[7] stated that patients who crossed over into the surgical group had significantly worse symptoms than the remainder of the control group before crossing over but achieved similar outcomes to the control and surgical groups.

Effect of Age

Only 1 study specifically examined the effect of age on outcomes. Gauffin et al[4] reported better outcomes for both rehabilitation and arthroscopic interventions for 55- to 64-year-old patients compared to younger patients aged 45 to 55 years.

Adverse Events

No study described a greater rate of adverse events in the arthroscopic group.

Lateral Meniscal Tears

No study examined outcomes of partial meniscectomy as a treatment for lateral meniscal tears.

Outcomes of Patients With Atraumatic MMTs Who Failed Nonoperative Management

The inclusion criteria for 4 of the 8 MMT studies included the failure of clinician-assessed nonspecific nonoperative management between 1 and 3 months. No MMT study examined the outcomes of patients who had undergone a structured rehabilitation program and continued to have severe self- described symptoms after randomization to an operative versus nonoperative intervention.

Outcomes of Patients Who Self-Reported Mechanical Symptoms

Self-reported mechanical symptoms were common in all studies. One study,[14] a secondary analysis of a previously published RCT, found no difference in patients with atraumatic self-described mechanical symptoms who underwent medial meniscectomy compared to a sham procedure. Kirkley et al[9] found no improvement in a subgroup of patients with OA and self-described mechanical symptoms compared to rehabilitation.

Progression of OA After Partial Meniscectomy

The study by Herrlin et al[5] found no difference in OA progression 5 years after partial medial meniscectomy compared to physical therapy.

Conclusion

All of the OA studies had a high risk of bias in at least 1 domain.

One OA study[12] had a low risk of bias from blinding. In this study, patients who were assessed clinically to have moderate to severe knee OA, in the absence of loose bodies or locking, showed no advantage of arthroscopic debridement over lavage or sham surgery.

In a study with a high risk of bias,[6] patients with isolated medial femoral condyle degenerative lesions benefited from an arthroscopic intervention compared to rehabilitation.

In a study with a high risk of bias,[8] arthroscopic patellofemoral chondroplasty did not benefit patients compared to nonoperative management.

In atraumatic MMTs,[15] in the absence of surgeon-assessed locking or locked knees or a repairable meniscal tear, a study with a low risk of bias showed no advantage of arthroscopic partial meniscectomy over sham surgery.

In a study with a high risk of bias in 1 domain,[14] in patients with an atraumatic onset of self-described mechanical symptoms, in the presence of an MMT, other than surgeon-assessed recent locking, a locked knee, or symptomatic loose bodies, there was no advantage to arthroscopic partial meniscectomy over sham surgery.

The role of arthroscopic surgery in lateral meniscal tears remains uncertain, as it has not been subjected to an RCT.

The role of subchondral drilling or microfracture undertaken in combination with osteotomy remains uncertain, as no RCTs exist comparing it to osteotomy alone.

Preservation of the medial or lateral meniscus by repair of the body or root, with or without degeneration of the joint, has not been subjected to an RCT.

No study investigated the role of diagnostic arthroscopic surgery in situations where MRI was inconclusive or unable to be performed. The value of MRI in the investigation of atraumatic nonlocking knee symptoms in the presence of OA remains uncertain.

No MMT study examined the outcomes of patients who failed a structured rehabilitation program by randomization to an operative versus nonoperative intervention.