Loss of the knee-ankle coupling and unrecognized elongation in Achilles tendon rupture: effects of differential elongation of the gastrocnemius tendon.

PURPOSE: The biarticular anatomy of the gastrocnemii is an important mechanism of knee-ankle coupling and differential elongation may affect this function leading to weakness of the push-off phase during the gait. Achilles tendon ruptures may cause detachment of the gastrocnemius tendon from the soleus aponeurosis with subsequent differential elongation of the individual subtendons. This study investigated the effects of such detachment by investigating tendon fusion levels of the two muscle groups, and the effect of sequential differential elongation of the gastrocnemius on the Achilles tendon resting angle (ATRA) and to the knee-ankle coupling. METHODS: Conjoined tendon length (CTL) was measured in 23 cadavers. ATRA in knee extension (ATRA 0) and 90-degree knee flexion (ATRA 90) was measured with the gastrocnemius tendons (GT) intact, transected and with the gap reduced in 5-mm increments. In 15 specimens, knee-ankle coupling was examined. RESULTS: Considerable anatomical variation was present with CTL ranging from 2 to 40% of fibular length. In the intact triceps, surae ATRA 0 differed from ATRA 90 by 6 degrees (p < 0.001). Cutting the gastrocnemius caused an immediate separation of the tendon ends by 19 mm. ATRA 0 and ATRA 90 increased 8 and 4 degrees (p < 0.001), significantly larger increase for ATRA 0 (p < 0.001). Lengthening the gastrocnemius 10 mm altered the coupling point 10 degrees towards dorsiflexion. Transfixing the gastrocnemius at the level of the gap where the Achilles was sectioned, decoupled the knee-ankle coupling in all but two specimens. A moderate correlation between CTL and length of the medial gastrocnemius tendon was found. CONCLUSIONS: A greater relative ATRA 0 than relative ATRA 90 indicates differential elongation of the gastrocnemius. By elongating the gastrocnemius the knee-ankle coupling point shifts dorsally, and 20 mm elongation completely decouples the knee-ankle coupling. Independent lengthening of the gastrocnemius may explain the loss of power experienced by some patients following acute Achilles tendon rupture despite what would appear to be appropriate approximation of the ruptured tendon ends. Recognizing this occurrence is crucial when treating Achilles tendon ruptures and such patients require surgical correction in order to avoid long-term weakness of push-off strength.

10-year follow-up after standardised treatment for Achilles tendinopathy.

BACKGROUND: Achilles tendinopathy is a common and often long-lasting injury. We present a 10-year follow-up on a pragmatic study on Achilles tendinopathy treated with controlled exercises supplemented with corticosteroid injections if necessary in order to continue training. METHODS: All patients who completed the original study (n=93) were invited for a 10-year follow-up. 83% participated. Patients were evaluated with ultrasound scanning (n=58) and with a questionnaire (n=77) using the same outcome measures as in the primary study. The 10-year overall outcome on a 4-point scale (excellent, good, fair, poor), other treatments and adverse event and present activity level were recorded. RESULTS: Excellent outcome was reported in 63% and good outcome in 27%. 76% reported an activity level at 75%-100% of preinjury level. The average Victorian Institute of Sports Assessment-Achilles score for all patients was 84 (SD 19). 16% had surgery. Three ruptures occurred 5-8 years after the primary study. The improvement from entry to 6 months in the primary study was maintained until 10-year follow-up. Insertional tendinopathy did not differ from mid-substance tendinopathy in any outcome measure (short term and long term). We encountered no prognostic markers on ultrasound for the long-term outcome; however, present heterogeneity and increased flow resemble present pain. Thickened tendons seem to maintain their thickness despite improvement of symptoms. CONCLUSION: One to two corticosteroid injections are a safe and effective supplement to controlled exercises in the treatment of Achilles tendon pain with no signs of deterioration in the very long term. Mid-substance and insertional tendinopathies benefit equally from this treatment.

Prospective analysis of a first MTP total joint replacement. Evaluation by bone mineral densitometry, pedobarography, and visual analogue score for pain.

BACKGROUND: We hypothesized that a total replacement of the first metatarsophalangeal joint (MTP-1) would alter the walking pattern with medialisation of the ground reaction force (GRF) of the foot and subsequently cause an increase in bone mineral density (BMD) in the medial metatarsal bones and a decline of BMD in the lateral metatarsal bones. METHODS: Twelve patients receiving total joint replacements (Roto-Glide(®)) of MTP-1 were enrolled in a prospective cohort. BMD and pedobarography of the heel bone and the metatarsal heads were performed preoperatively and at least 12 months postoperatively. RESULTS: BMD in the lateral metatarsals and GRF under the lateral column of the operated feet decreased significantly on the operated feet. CONCLUSIONS: Total joint replacement of MTP-1 tends to reduce GRF under the lateral column of the foot causing a corresponding decline in BMD and pedobarographic measures. Our findings support the further use of the Roto-Glide(®) prosthesis for osteoarthritis of the first metatarsophalangeal joint.