Bilateral atraumatic medial meniscal tears in a 17-year-old rower

Abstract

Meniscal injury produces disability in a large portion of the population, and sports injuries are a common cause. Atraumatic meniscal tears may occur after repetitive low-energy loading. Rowing is a highly technical sport and very demanding on an athlete’s body. There are numerous reports on patellofemoral and iliotibial band friction syndrome in rowers but there is an extremely low incidence of meniscal tears reported in these athletes. This is a unique case report of a young adolescent athlete who suffered bilateral medical meniscal tears during sporting activity. Rowing is a low impact sport making this an unusual occurrence, especially in a young individual. This case report highlights the importance of considering all training activities when trying to isolate the mechanism of injury in an athlete.

BACKGROUND

Rowing is a highly technical sport and demanding on an athlete’s body. There are numerous reports on patellofemoral pain and iliotibial band friction syndrome in rowers, but there is an extremely low incidence of meniscal tears reported.¹ This is a unique case as meniscal tears are uncommon in the sport of rowing especially in the adolescent age group. It also highlights the importance of considering all training activities when trying to isolate the mechanism of injury in an athlete.

CASE PRESENTATION

A 17-year-old, 1.93 m tall female competitive rower presented with right anterior knee pain for duration of 1 year with no history of trauma. She had been seen by two previous primary care sport medicine doctors and was diagnosed with patellofemoral pain syndrome. She had undergone a course of appropriate physiotherapy, but remained symptomatic. Physical examination was consistent with patellofemoral syndrome with no signs of internal derangement.

INVESTIGATIONS

Given the long duration of symptoms in this motivated and compliant athlete, imaging tests were ordered to rule out other potential causes of her knee pain. The plain radiographs were normal but MRI revealed an obliquely oriented medial meniscus tear through the posterior horn. The athlete was referred to an orthopaedic surgeon for arthroscopy. In the meantime the athlete returned to the clinic with similar symptoms on the left knee. She experienced a catching sensation and pain with stairs, squatting and running. Physical exam revealed medial joint line tenderness. MRI showed a similar medial meniscal tear involving the posterior horn.

DIFFERENTIAL DIAGNOSIS

• Patellofemoral pain syndrome

• Chondromalasia patella

• Meniscal injury

• Plica syndrome

• Hoffa fat pad syndrome

TREATMENT

Bilateral arthroscopic surgery was performed to resect the complex meniscal tears. The patellofemoral compartment and articular surface were well preserved.

OUTCOME AND FOLLOW-UP

In follow-up, the athlete was asymptomatic and competing at an elite level.

DISCUSSION

Atraumatic meniscal tears occur after repetitive low-energy loading. As a result the athlete often cannot identify a specific injury that signalled the onset of their knee symptoms. Making a clinical diagnosis of a torn meniscus in this setting may be difficult and thus advanced imaging may be required. Several authors have demonstrated that although no single clinical test is reliable for diagnosing meniscal tears, a combination of tests increases the sensitivity and specificity.^2,3

The importance of the functional role of the meniscus in joint congruence, load transmission, shock absorption, joint stability and proprioception has been well established.^4,5 The incidence of meniscal injury resulting in meniscectomy is 61 per 100 000 patient population with medial meniscal injury accounting for approximately 81% of tears.⁶ Terzidis et al⁵ arthroscopically examined 378 knees in 364 athletes (only 11 rowers) aged 16–32 years with isolated meniscal lesions. Overall, 69% of tears were located medially. The greater incidence of medial meniscal tears occurs due to the firm connection with the joint capsule and deep collateral ligament at the periphery, especially at the posterior horn.^5,6 A study by Venkatachalam et al⁴ suggests that an isolated atraumatic meniscal tear in a stable knee may not be amenable to surgical repair, even if the tear is peripheral. The results of the study showed a 66% failure rate in these cases and propose that atraumatic meniscal injuries may be better treated by meniscectomy at presentation rather than attempted repair.⁴

In squatting positions in particular (ie, the catch and drive phase, see fig 1), with external rotation, the tight attachment of the meniscus on the tibia exposes the posterior horn to significant tension.⁶ Conversely, it may well be the approach to the catch that is the issue. One of the main distinguishing factors between experienced and novice rowers is their control during the recovery phase. Rowing can be likened to performing a squat with a bar. The drive phase in rowing is like the upward motion (concentric phase) of the squat. The recovery is similar to the downward motion (eccentric phase) during knee flexion and lowering of the weight. If the lowering phase is too rapid and lacks control, detrimental forces can be transmitted to the knee. Less experienced rowers tend to “rush the slide” to get to the next stroke in instead of relaxing and gliding up to the next catch. This checks the boat speed and basically puts the brakes on, because the momentum of the boat is forced in the incorrect direction.¹

Figure 1.

Rowers in the catch position. Informed consent was obtained for publication of this figure.

While rowing, the hip and knee angular velocities that allow maximal power to be developed are approximately 150 and 200 °/s respectively.⁷ Nelson and Widule⁸ observed that a greater peak angular knee velocity during the drive phase of the rowing stroke improved the biomechanical efficiency in female college rowers.⁹ This suggests that power training techniques may be more beneficial than classical strength training for rowers. Common weight training exercises such as squats, cleans and deadlifts may play a factor in the mechanism of injury due to the significant force applied to the knee.¹ Inexperienced athletes often perform squats and push off at the catch in an incorrect valgus or “knock-kneed” position. It has been shown that 50% of injuries that occur in elite rowers are due to land-based training, including ergometer use and weights.⁹ Rowing on the ergometer can produce much higher forces on the joint compared to rowing on the water. The drag setting on the flywheel of the ergometer, which adjusts the wind resistance on the vent, is typically set at 3 or 4 out of 10 by elite rowers. This setting is most representative of the feeling on the water. Many inexperienced rowers train at a setting of 5 or higher, thinking that more drag is better, which in turn places higher forces on the knee.

This is a rare case of bilateral atraumatic meniscal injury in a young female rower. Although uncommon, it is important to keep this diagnosis in the differential when managing high demand athletes with symptoms similar to patellofemoral syndrome but fail to respond to appropriate treatment. All training activities and technique should be considered when trying to isolate the mechanism of injury. The majority of the current research reviewed is anecdotal as there is limited data on the force applied to the meniscus during the different phases of rowing. This highlights the need for future research and well designed clinical studies in this specific athlete population.

LEARNING POINTS

• The lack of specificity of meniscus physical exam manoeuvres can make the diagnosis of meniscal pathology a challenge

• Meniscus injuries are typically assumed to be the result of weight-bearing activities but we need to consider closed chain overuse injuries as a potential mechanism.

• The biomechanics of rowing and of weight training need to be considered as possible contributors to overuse meniscus injuries.