KNEE PAIN – Non Surgical Solutions
Patients with osteoarthritis (OA) of the knee who also have pain in other joints are more likely to experience greater knee pain, according to new research.
Dr Pradeep Suri, MD, with the New England Baptist Hospital, in Boston, Massachusetts, and colleagues reported their findings in the December print issue of Arthritis Care & Research. (November 24, 2010)
Specifically, lower back, foot, and elbow pain on the same side as the affected knee were associated with more severe knee pain.
According to the researchers, previous studies have suggested that concurrent low back pain may be associated with more severe symptoms of knee OA. “Pain in other musculoskeletal locations, including the hip and the foot, may also be associated with symptoms in the knee,” the study authors write.
This may have several explanations. For example, lower back pain and other joint pains may “directly cause increased knee pain due to the biomechanical interrelationship of joints in the kinetic chain,” the study authors note.
In this study, the researchers analyzed data from the Osteoarthritis Initiative, a database including 1389 individuals aged 45 to 79 years with symptomatic tibiofemoral knee OA. Musculoskeletal pain in other areas, including the lower back, neck, shoulder, elbow, wrist, hand, hip, knee, ankle, or foot, was also documented by the patients.
Of the participants, 57.4% reported having lower back pain. A pain score (Western Ontario McMaster Universities Osteoarthritis Index [WOMAC], possible range, 0 – 20), applied to the more symptomatic knee, averaged 6.5 ± 4.1 in participants with low back pain vs 5.2 ± 3.4 in participants without low back pain (P < .0001).
Multivariate analyses found that only low back pain, but not pain at other locations, was significantly associated with increased WOMAC knee pain score (P < .0001). However, when all locations were considered simultaneously, only ipsilateral elbow (P = .02), ipsilateral foot (P = .02), and low back pain (P = .002) correlated significantly with knee pain.
In addition, pain at more than 1 location was associated with greater WOMAC knee pain, especially in those with 4 or more pain locations (P < .0001).
According to the researchers, understanding these associations “may help to identify patients who are at risk for poor outcomes following (total knee arthroplasty), and patients who may benefit from co-interventions to treat musculoskeletal pain in other locations.”
“Our findings suggest that pain external to the knee may exert small but clinically significant effects on WOMAC pain score, even when the WOMAC is applied in a knee-specific manner,” the study authors conclude. “…stratification by musculoskeletal pain comorbidity may be a factor worth considering in trial design.” They add that interventions that simultaneously target knee and nonknee pain may improve overall knee-related outcomes.
“These findings highlight an important consideration in osteoarthritis diagnosis and treatment assessment, which is that many of our outcome metrics, such as the commonly used WOMAC pain, are subject to a great deal of noise,” said independent commentator Janie Astephen Wilson, PhD, with Dalhousie University, in Halifax, Nova Scotia, Canada. “They are highly influenced by a variety of factors including comorbidity,” she told Medscape Medical News.
According to Dr. Astephen Wilson, scores such as the WOMAC do not reflect the structural state of the disease and have been shown to be unrelated to the measures of mechanical loading of the knee joint (which presumably relate to the progression of the disease). “If our aim is to capture the symptomatic state of the disease, then we must consider all of the factors (such as comorbidity and LBP [low back pain]) that may be influencing our metrics,” she said.
“There have been a number of studies that have related pain in other lower extremity joints to knee pain, but few studies consider pain outside of the lower extremity,” she said. “This study further supports the results of these previous studies by additionally relating upper extremity and low back pain to knee pain, and would support the hypothesis of a less biomechanical association between these comorbidities.”
The study was supported by the National Institutes of Health as well as commercial funding from Merck Research Laboratories, Novartis Pharmaceuticals Corp, GlaxoSmithKline, and Pfizer, Inc. Dr. Astephen Wilson has disclosed no relevant financial relationships.
Tenderness / Pain
Finding, the exact location of a patient’s pain (when possible) and correlating it to potential abnormalities or specific anatomic structures is an essential part of the physical exam. We perform a standard systematic exam on every patient and we avoid irritating the area of maximal tenderness until all other structures have been palpated. This prevents the patient from guarding due to pain during the exam.
Joint Line Pain:
Joint line pain can be indicative of a tear of the lining of the joint (the capsule), a meniscus tear, or may indicate abnormalities with the bone or cartilage at the joint line (chondromalacia, arthritis, osteochondritis dissecans, etc). In the evaluation of joint line pain, we perform this concurrent with either a varus or valgus stress test. While we are applying a stress across the joint, we place our fingers directly over the joint line to assess for joint line pain, a clunk (which may indicate a peripheral meniscal tear), or intraarticular crepitation (which may indicate cartilage damage or a meniscal tear). We try to work with the patient to determine if the pain is just under our fingers (which may indicate an injury to the joint line capsule) or deeper inside the joint.
Tenderness at the tibial tuberosity is primarily due to Osgood-Schlatter’s syndrome, or its residual, or deep infrapatellar bursitis. A bony prominence over the tibial tubercle may indicate either ongoing Osgood-Schlatter’s irritation in an adolescent with open growth plates, or the residual of Osgood-Schlatter’s in adults.
In adults, the most common cause of continued pain after Osgood-Schlatter’s syndrome is a bony ossicle in the patellar tendon or in the deep infrapatellar bursa. The deep infrapatellar bursa is located slightly proximal to the patella tendon attachment on the tibial tubercle (LaPrade, 1998). It is most easily palpated on the lateral aspect of the bursa just proximal to the tibial tubercle. Tenderness in either of these two locations usually goes hand in hand with tight hamstrings.
Palpation of a possible suprapatella plica.
Tenderness of the semimembranosus direct arm insertion on the posteromedial aspect of the knee.
A bursa just proximal to the insertion is often inflammed in patients with tight hamstrings.
Tenderness of the biceps femoris- FCL bursa on the lateral aspect of the knee.
A bursa is located at the point where the anterior arm of the long biceps crosses lateral to the fibular collateral ligament (LaPrade, 1997)
There are multiple anatomic reasons for patellofemoral joint pain. The majority of these can be palpated during a physical examination to help differentiate the source of pain. This in turn may be useful in choosing the proper rehabilitation protocol for a patient. Suprapatellar plica irritation is the most common finding we will see in patients with patellofemoral pain. Pain at the pes anserine bursa, semimembranosis bursa, deep infrapatellar bursa (LaPrade, 1998), or the FCL-biceps femoris bursa (LaPrade and Hamilton, 1997) usually indicates that a patient has associated tight hamstrings and the sequelae from the extra stress on the joint.
Pain at the inferior pole of the patella is usually indicative of patellar tendonitis. Pain at the quadriceps insertion on the proximal patella may indicate a partial quadriceps tendon tear, quadriceps tendonitis, or the residual of a previous injury or surgery. We do not believe that one can palpate the medial or lateral facets of the patella independent of pushing on the plica (or associated joint retinaculum).
Our belief is that the term chondromalacia patella is a wastebasket term for anterior knee pain without breaking down the individual anatomic components. For this reason, we discourage the use of the term chondromalacia patella except in those patients who have been found via MRI or arthroscopy to have a well-localized cartilage lesion to their patella which is causing pain or in those patients who have an associated bone scan which shows increased uptake around this area.
Deep Joint Pain:
Pain deep inside the joint can be either due to a posterior horn meniscal tear, a Baker’s cyst, a fabella syndrome (on the lateral side of the joint), ganglion cysts of the cruciate ligaments, pigmented villnodular synovitis, lipoma arborescens (LaPrade, et al, 1995) or other pathology. Pain deep inside the knee with maximal knee flexion is very useful to help determine if there is a posterior horn meniscal tear. Pain at the posteromedial aspect of the joint just above the direct arm attachment of the semimembranosis and its intersection with the medial head of the gastrocnemius is usually indicative of a Baker’s cyst. Pain along the lateral aspect of the posterior joint, in the region of a fabella, which is accentuated with ankle dorsiflexion, may be indicative of a fabella syndrome or irritation due to arthritis of the fabellofemoral joint.
Superficial Joint Pain:
A superficial infection may be painful and is usually accompanied by increased warmth and redness of the region. Superficial pain over the anterior aspect of the joint may be indicative of a prepatellar bursitis. Pain over the anteromedial aspect of the joint, just distal to the joint line, may be indicative of an irritation of the infrapatellar branch of the saphenous nerve in a patient with a previous contusion or surgery in this area. Pain over the lateral or posterolateral aspect of the joint just distal to the fibular head may be indicative of a common peroneal nerve irritation. This could indicate either localized nerve entrapment or potentially a herniated disk pushing on a nerve root.
Tenderness at the joint line upon flexion of the knee.
Pain deep inside the knee with maximal knee flexion is most often indicative of a posterior horn meniscal tear.
Pain over the anterior aspect of the knee with deep knee flexion is usually found in patients with patellofemoral dysfunction.
In these patients, they may have pain from plical irritation, patellofemoral chondromalacia, or other anterior joint pathology.
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