Meniscal abnormalities linked to poor knee proprioception

PHILADELPHIA – Meniscal abnormality has long been suggested to be a contributor to poor joint proprioception, but evidence to make the case was not available until now.

An analysis of MRI data from 105 patients with knee osteoarthritis (OA) revealed that reduced proprioceptive accuracy was significantly associated with the number of regions with meniscal abnormalities (P = .006) and the extent of abnormality (P = .02).

This was true independent of muscle strength, joint laxity, pain, age, gender, body mass index, or duration of knee complaints. Patients with other neurologic conditions that could compound the results were also excluded from the analysis.

"This is the first study showing that reduced proprioceptive accuracy is associated with medial meniscal abnormalities in knee osteoarthritis," Dr. Martin van der Esch said at the World Congress on Osteoarthritis.

Knee proprioception is important for protection against excessive movement, stabilization during static postures, and coordination of movements. It diminishes with age and in the presence of OA.

The clinical implication of the results could be a predictive one, said Dr. van der Esch, who is with the Amsterdam Rehabilitation Research Center-Reade, the Netherlands.

"Patients with knee OA and meniscal abnormalities are strongly at risk for developing neuromuscular impairments and therefore at risk for developing limitations in daily activities," he said in an interview. "The knowledge has no consequences at the moment for therapeutic interventions."

Meniscal abnormalities can lead to impaired proprioceptive accuracy and knee OA through knee instability and overloading of the medial meniscus. Conversely, knee OA can lead to a meniscal abnormality through weakening of the meniscal structure, thereby reducing proprioceptive accuracy and creating something of a self-perpetuating cycle, he explained at the meeting, sponsored by the Osteoarthritis Research Society International.

To explore these associations, 105 patients with established knee OA in the Amsterdam Osteoarthritis cohort underwent 3-Tesla MRI of the affected knee. The Boston-Leeds OA Knee Scoring (BLOKS) system was used to score the number of regions with a meniscal abnormality and the extent of the abnormality. In the case of bilateral disease, the knee most affecting daily activities was imaged.

Proprioception was measured in a movement detection test using a computer-controlled, motion-detecting device created at the University of Amsterdam. In motion tests, the joint is moved slowly and passively and the patient is asked to detect the start of the movement as quickly as possible.

At baseline, the mean proprioceptive accuracy was 2.9°, mean quadriceps strength 0.89 N-m/kg, and mean joint laxity 6.9°.

Patients had been symptomatic for an average of 11 years, were mostly women (70%), and had an average age of 61.4 years.

MRI-detected medial meniscal abnormalities were found in the anterior horn in 78% of patients, in the meniscal body in 80%, and in the posterior horn in 89.5%. Specifically, tears were present in 5%, 12.5%, and 28.6%, respectively, and maceration in 26.7%, 45%, and 36%.

The mean proprioceptive inaccuracy increased from 1.83°when no region had a meniscal abnormality to 2.09° for one region with an abnormality, 2.57° with two regions, and 3.20° with three regions, indicating that the patient needed more time to detect a movement, Dr. van der Esch said.

Proprioceptive inaccuracy followed a similar pattern with regard to the extent of abnormality: 1.83° with no abnormality, 2.70° with a meniscal signal abnormality, 2.85° with a tear, and 3.19° with maceration.

Members of the audience questioned whether ligamentous laxity may have contributed to poor proprioception, but previous studies have shown no association between laxity and proprioception, Dr. van der Esch said. "So, it’s hard to believe this could be influencing these results," he added.

A follow-up study is underway to find causal relationships between meniscal abnormalities and knee joint proprioception, with additional MRIs of the cohort to be taken at the end of the year, he said.

As for what might be causing the poor knee proprioception, one of the most fitting hypotheses is the existence of low-grade inflammation in the joint, which is responsible for a decrease in mechanoreceptors within the inner layers of the capsule. Another feasible explanation is mechanical destruction of the capsule due to a loss of the meniscus itself, partly by meniscectomy or maceration by degeneration, he said.

Dr. van der Esch reported no relevant disclosures.

[email protected]

PHILADELPHIA – Meniscal abnormality has long been suggested to be a contributor to poor joint proprioception, but evidence to make the case was not available until now.

An analysis of MRI data from 105 patients with knee osteoarthritis (OA) revealed that reduced proprioceptive accuracy was significantly associated with the number of regions with meniscal abnormalities (P = .006) and the extent of abnormality (P = .02).

This was true independent of muscle strength, joint laxity, pain, age, gender, body mass index, or duration of knee complaints. Patients with other neurologic conditions that could compound the results were also excluded from the analysis.

"This is the first study showing that reduced proprioceptive accuracy is associated with medial meniscal abnormalities in knee osteoarthritis," Dr. Martin van der Esch said at the World Congress on Osteoarthritis.

Knee proprioception is important for protection against excessive movement, stabilization during static postures, and coordination of movements. It diminishes with age and in the presence of OA.

The clinical implication of the results could be a predictive one, said Dr. van der Esch, who is with the Amsterdam Rehabilitation Research Center-Reade, the Netherlands.

"Patients with knee OA and meniscal abnormalities are strongly at risk for developing neuromuscular impairments and therefore at risk for developing limitations in daily activities," he said in an interview. "The knowledge has no consequences at the moment for therapeutic interventions."

Meniscal abnormalities can lead to impaired proprioceptive accuracy and knee OA through knee instability and overloading of the medial meniscus. Conversely, knee OA can lead to a meniscal abnormality through weakening of the meniscal structure, thereby reducing proprioceptive accuracy and creating something of a self-perpetuating cycle, he explained at the meeting, sponsored by the Osteoarthritis Research Society International.

To explore these associations, 105 patients with established knee OA in the Amsterdam Osteoarthritis cohort underwent 3-Tesla MRI of the affected knee. The Boston-Leeds OA Knee Scoring (BLOKS) system was used to score the number of regions with a meniscal abnormality and the extent of the abnormality. In the case of bilateral disease, the knee most affecting daily activities was imaged.

Proprioception was measured in a movement detection test using a computer-controlled, motion-detecting device created at the University of Amsterdam. In motion tests, the joint is moved slowly and passively and the patient is asked to detect the start of the movement as quickly as possible.

At baseline, the mean proprioceptive accuracy was 2.9°, mean quadriceps strength 0.89 N-m/kg, and mean joint laxity 6.9°.

Patients had been symptomatic for an average of 11 years, were mostly women (70%), and had an average age of 61.4 years.

MRI-detected medial meniscal abnormalities were found in the anterior horn in 78% of patients, in the meniscal body in 80%, and in the posterior horn in 89.5%. Specifically, tears were present in 5%, 12.5%, and 28.6%, respectively, and maceration in 26.7%, 45%, and 36%.

The mean proprioceptive inaccuracy increased from 1.83°when no region had a meniscal abnormality to 2.09° for one region with an abnormality, 2.57° with two regions, and 3.20° with three regions, indicating that the patient needed more time to detect a movement, Dr. van der Esch said.

Proprioceptive inaccuracy followed a similar pattern with regard to the extent of abnormality: 1.83° with no abnormality, 2.70° with a meniscal signal abnormality, 2.85° with a tear, and 3.19° with maceration.

Members of the audience questioned whether ligamentous laxity may have contributed to poor proprioception, but previous studies have shown no association between laxity and proprioception, Dr. van der Esch said. "So, it’s hard to believe this could be influencing these results," he added.

A follow-up study is underway to find causal relationships between meniscal abnormalities and knee joint proprioception, with additional MRIs of the cohort to be taken at the end of the year, he said.

As for what might be causing the poor knee proprioception, one of the most fitting hypotheses is the existence of low-grade inflammation in the joint, which is responsible for a decrease in mechanoreceptors within the inner layers of the capsule. Another feasible explanation is mechanical destruction of the capsule due to a loss of the meniscus itself, partly by meniscectomy or maceration by degeneration, he said.

Dr. van der Esch reported no relevant disclosures.

[email protected]

PHILADELPHIA – Meniscal abnormality has long been suggested to be a contributor to poor joint proprioception, but evidence to make the case was not available until now.

An analysis of MRI data from 105 patients with knee osteoarthritis (OA) revealed that reduced proprioceptive accuracy was significantly associated with the number of regions with meniscal abnormalities (P = .006) and the extent of abnormality (P = .02).

This was true independent of muscle strength, joint laxity, pain, age, gender, body mass index, or duration of knee complaints. Patients with other neurologic conditions that could compound the results were also excluded from the analysis.

"This is the first study showing that reduced proprioceptive accuracy is associated with medial meniscal abnormalities in knee osteoarthritis," Dr. Martin van der Esch said at the World Congress on Osteoarthritis.

Knee proprioception is important for protection against excessive movement, stabilization during static postures, and coordination of movements. It diminishes with age and in the presence of OA.

The clinical implication of the results could be a predictive one, said Dr. van der Esch, who is with the Amsterdam Rehabilitation Research Center-Reade, the Netherlands.

"Patients with knee OA and meniscal abnormalities are strongly at risk for developing neuromuscular impairments and therefore at risk for developing limitations in daily activities," he said in an interview. "The knowledge has no consequences at the moment for therapeutic interventions."

Meniscal abnormalities can lead to impaired proprioceptive accuracy and knee OA through knee instability and overloading of the medial meniscus. Conversely, knee OA can lead to a meniscal abnormality through weakening of the meniscal structure, thereby reducing proprioceptive accuracy and creating something of a self-perpetuating cycle, he explained at the meeting, sponsored by the Osteoarthritis Research Society International.

To explore these associations, 105 patients with established knee OA in the Amsterdam Osteoarthritis cohort underwent 3-Tesla MRI of the affected knee. The Boston-Leeds OA Knee Scoring (BLOKS) system was used to score the number of regions with a meniscal abnormality and the extent of the abnormality. In the case of bilateral disease, the knee most affecting daily activities was imaged.

Proprioception was measured in a movement detection test using a computer-controlled, motion-detecting device created at the University of Amsterdam. In motion tests, the joint is moved slowly and passively and the patient is asked to detect the start of the movement as quickly as possible.

At baseline, the mean proprioceptive accuracy was 2.9°, mean quadriceps strength 0.89 N-m/kg, and mean joint laxity 6.9°.

Patients had been symptomatic for an average of 11 years, were mostly women (70%), and had an average age of 61.4 years.

MRI-detected medial meniscal abnormalities were found in the anterior horn in 78% of patients, in the meniscal body in 80%, and in the posterior horn in 89.5%. Specifically, tears were present in 5%, 12.5%, and 28.6%, respectively, and maceration in 26.7%, 45%, and 36%.

The mean proprioceptive inaccuracy increased from 1.83°when no region had a meniscal abnormality to 2.09° for one region with an abnormality, 2.57° with two regions, and 3.20° with three regions, indicating that the patient needed more time to detect a movement, Dr. van der Esch said.

Proprioceptive inaccuracy followed a similar pattern with regard to the extent of abnormality: 1.83° with no abnormality, 2.70° with a meniscal signal abnormality, 2.85° with a tear, and 3.19° with maceration.

Members of the audience questioned whether ligamentous laxity may have contributed to poor proprioception, but previous studies have shown no association between laxity and proprioception, Dr. van der Esch said. "So, it’s hard to believe this could be influencing these results," he added.

A follow-up study is underway to find causal relationships between meniscal abnormalities and knee joint proprioception, with additional MRIs of the cohort to be taken at the end of the year, he said.

As for what might be causing the poor knee proprioception, one of the most fitting hypotheses is the existence of low-grade inflammation in the joint, which is responsible for a decrease in mechanoreceptors within the inner layers of the capsule. Another feasible explanation is mechanical destruction of the capsule due to a loss of the meniscus itself, partly by meniscectomy or maceration by degeneration, he said.

Dr. van der Esch reported no relevant disclosures.

[email protected]