Tears and ruptures of the anterior cruciate ligament (ACL) in the knee are common in sport, but there is considerable controversy regarding appropriate treatment. In a recent review, Belgian orthopedic specialist P. P. Casteleyn of Vrije University in Brussels takes a look at the outcomes of five common treatments - the conservative, non-surgical approach (rest, strengthening, management of inflammation), plus four surgical interventions - primary repair of the ACL (13 published papers and 1205 actual cases), extra-articular tenodesis (four papers and 232 cases), ACL prosthetic replacement using synthetic materials (five papers and 370 cases), and - the most popular surgical manoeuvre - ACL reconstruction (26 papers and 2693 total cases). Only reports with a minimum follow-up of four years were included in Casteleyn's analysis ('Management of anterior cruciate ligament lesions: surgical fashion, personal whim or scientific evidence? Study of medium and long-term results,' Acta Orthop Belg Sep, Volume 65(3), pp. 327-39, 1999).
Casteleyn found that clinical laxity (excessive looseness and motion at the knee joint) was present in almost all conservatively treated cases, in about half of the patients with primary repair, extra-articular tenodesis, and synthetic substitution, and in just one-third of the individuals with ACL reconstruction. Despite their loose knees, the conservatively treated group did enjoy two advantages - they had the lowest rate of follow-up surgery (4.6 percent), and they also benefited from the most minimal rate of osteoarthritic problems (12 per cent) during the period of analysis. The need for subsequent surgery to repair a meniscus (a naturally present, cartilaginous, shock-absorbing pad within the knee) was lowest in patients who underwent ACL reconstruction (3.5%). Importantly, activity level was not controlled during the follow-up period (the ACL-reconstruction group was most active in sports), yet Casteleyn's research seems to offer a fairly realistic view of the outcomes of common treatments of ACL lesions, and on the relationship between treatment, activity level, and osteoarthritis.
And where exactly should you put a reconstructed ACL?
Speaking of treatments for anterior cruciate ligament injuries, one of the most challenging problems faced by surgeons carrying out ACL reconstructions is deciding where exactly to place the new, reconstructed ligament. Now, researchers at the Department of Orthopaedic Surgery and Traumatology at the University of Novi Sad in Yugoslavia claim that they have perfected a superior way to select the placement position - and thus most effectively stabilise the reconstructed knee ('A new positioning device for precise femoral insertion of the anterior cruciate ligament autograft,' Knee Surg Sports Traumatol Arthrosc, vol. 8(3), pp. 149-53, 2000).
Yugoslavian scientists M. Milankov and N. Miljkovic (e-mail address: email@example.com) point out that several methods for localising a point of femoral insertion for the ACL graft and identifying a centre of the femoral tunnel have been proposed, including free-hand drilling with 'eyeballing', the use of tensiometers or isometers, fluoroscopic or radioscopic control, and aiming devices. As a hopefully superior alternative, they propose the utilisation of pre-operative radiographic measurements (using the quadrant method) to determine the precise location for femoral attachment of the ACL autograft. Milankov and Miljkovic indicate that their technique takes into account wide structural variations among individual patients, provides an exact pre-operative plan for femoral insertion, and eliminates numerous potential sources of errors in ACL positioning.
Strengthening the knee after ACL repair
Improving knee strength in various planes of motion is essential for 'rehabbing' the knee following conservative or surgical treatment for ACL injury. Last issue on page two fitness and conditioning specialist Walt Reynolds gave an exercise which did a fine job of restoring functional strength to knees recovering from ACL trauma (athletes should make sure they don't perform them until they get the OK from a sports-care professional) Here is Walt's second exercise for dealing with ACL injury:
Start by running at half-speed straight ahead for about five metres. At the five-metre mark, cut quickly to your left for several strides by pushing off your right foot and moving in a left-forward (diagonal) direction. Then cut back toward the right for several strides by pushing off your left foot and moving in a right-forward (diagonal) direction. Repeat this sequence for a total of eight to 10 cuts (four to five to the right and four to five to the left). Perform three to five sets of this exercise with a break of 30 to 45 seconds between each run.
Gradually increase the intensity of your zig-zag runs over a period of four to six weeks by running faster and also by changing the number of strides between direction changes (vary the number of strides between one and five). If you participate in sports that require running backwards (e. g., football, rugby, and basketball), complete some of the sets in a backward direction.
Zig-zag runs help develop the balance and body control required to move in multiple directions at various speeds. These runs require the knee joints to move through a number of different angles and directions, thus mimicking movements which can lead to ACL injury in unprepared athletes.
Is 'backward biking' a good rehab activity?
Backward walking and jogging have often been recommended as decent aerobic and leg-strengthening activities for injured athletes, especially for individuals with knee problems, primarily because backward gait is linked with reduced patellofemoral joint loads, compared with normal walking and jogging. Rehabilitation specialists have also begun to use 'backward biking', i. e., reverse pedalling on the bike, during rehab exercises for injured athletes, despite the fact that forces acting on the knees during backward pedalling have been poorly understood.
Now, new research carried out by R. Neptune and S. Kautz (e-mail address firstname.lastname@example.org) at the Palo Alto Health Care System in Palo Alto, California, reveals that backward pedalling may indeed be useful for individuals with certain knee disorders - but is contradicted in other cases ('Knee joint loading in forward versus backward pedalling: implications for rehabilitation strategies,' Clin Biomech (Bristol, Avon), Aug; Volume 15(7), pp. 528-35, 2000). When they quantified tibiofemoral and patellofemoral joint-reaction forces, Neptune and Kautz found that lower tibiofemoral compressive loads - but higher patellofemoral compressive loads - were observed in backward pedalling, compared with normal cycling. Lower 'shear forces' were also observed during backward pedalling near peak extension of the knee.
Neptune and Kautz concluded that backward pedalling is associated with reduced tibiofemoral compressive loads and thus might be quite useful for patients with knee disorders such as menisci damage and osteoarthritis. However, reverse cycling can actually produce greater compressive forces between the patella and tibia, compared with normal cycling, and thus is probably not optimal for athletes experiencing patellofemoral pain - or for individuals recovering from anterior-cruciate-ligament injury or reconstruction.
Cyclists with low-back pain should adjust their saddles
Up to 70 per cent of regular cyclists suffer from cervical, dorsal, or lumbar back pain, suggesting that there is something about cycling which is not so good for the back. To find out whether adjustments in biking posture might lower the frequency of back problems in cyclists, researchers at The Chaim Sheba Medical Centre in Tel Hashomer, Israel, recently performed serial fluoroscopic studies of cyclists sitting on different types of bicycles (sports, mountain, and city). Pelvic/spine angles were measured at different seat angles, and the related force vectors acting on the back were analysed ('Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists,' Br J Sports Med, Dec, Vol. 33(6), pp. 398-400, 1999).
The Israeli researchers found that on almost all bikes there was a tendency towards hyperextension of the pelvic/spine angle which resulted in an increase in tensile forces acting on the spine. The Israelis noted that these forces could easily be reduced by adjusting the seat angle so that the front of the seat inclined downward (i. e., the back of the seat was higher than the front).
Members of a cycling club who complained of low-back pain then trained systematically with the adjusted seats. Most of these athletes (>70 per cent) reported major improvements in the incidence and magnitude of their back pain. As the researchers concluded, 'The incidence and magnitude of back pain in cyclists can be reduced by appropriate adjustment of the angle of the saddle. It is important that these findings be conveyed to cyclists, bicycle salesmen, trainers, and members of the general public who engage in cycling, in order to decrease the prevalence of back pain.'