TO THE EDITOR:
Regarding the reply of Dr. Pfeiffer and Dr. Cracchiolo in the Correspondence section of The Journal (78-A: 150, Jan. 1996) to a Letter to the Editor regarding their article "Clinical Results after Tarsal Tunnel Decompression" (76-A: 1222—1230, Aug. 1994), if the true anatomy3 of the laciniate ligament and the contents of the tunnel are ignored, the results of tarsal tunnel decompression will remain unsatisfactory. Contrary to general belief, the laciniate ligament is not undivided. From my investigative experience4,5 completed in 1972, the laciniate ligament proved to be compartmentalized, forming separate enclosures for the posterior tibial nerve, including the proximal portion of two plantar nerves as well as three tendons (the posterior tibial, flexor digitorum longus, and flexor hallucius longus). Six structures, not just the posterior tibial nerve, are subject to ligamentous pressure. Constriction of the individually contained tendons under the multilocular ligament can cause weakness of the involved extrinsic muscles, pain, and possibly positional deformity.
Keck1 as well as Lam2 described encroachment on the posterior tibial nerve, and later authors6,7 mentioned neurolysis of the plantar nerves; however, the important tendinous connection appeared in my description of the collective relationship of the six tunnel structures4,5. Pfeiffer and Cracchiolo serendipitously mentioned the relationship between the posterior tibial tendon and the tunnel.
Regardless of the nomenclature, understanding the true anatomy of the tarsal tunnel and completely decompressing the six structures (the medial and lateral plantar nerves toward the base of the first and fifth metatarsals, respectively) leads to nearly 100 per cent successful results.
H. P. Roosth, M.D.: Department of Orthopaedics and Rehabilitation, University of Texas Medical Branch, 1335 Santa Fe, Corpus Christi, Texas 78404
Dr. Pfeiffer and Dr. Cracchiolo reply:
In our study, we did decompress the posterior tibial nerve and the proximal portions of the medial and lateral plantar nerves. Although we frequently saw the posterior tibial tendon and the flexor digitorum longus, we never noted any evidence of synovitis surrounding the tendons and we did not routinely decompress them.
Perhaps the greatest difference between our experiences and Dr. Roosth's is that Dr. Roosth's patients were children while all of ours were adults. We do not have any experience with patients in the pediatric age-group. Furthermore, the article in Orthopaedics Today5 included comments by Mann, Davidson, and Goldner, who all challenged Dr. Roosth's findings; it was a vigorous and lively debate.
Conversely, we have managed several patients who had tenosynovitis involving the posterior tibial tendon, the treatment of which included operative decompression of the tendon. None of these patients had the slightest clinical evidence of tarsal tunnel syndrome.
We continue to be skeptical regarding a diagnosis of tarsal tunnel syndrome in the absence of any anatomical abnormality causing pressure either on the nerve or within the tarsal canal. However, since we do not have any good ideas as to how to improve our results with operative management of patients who have suspected tarsal tunnel syndrome, we have no objections to at least checking the three tendon sheaths and performing a tenolysis when indicated.
It is hard to argue with "nearly 100 per cent successful results," even in children.
William H. Pfeiffer, M.D.: Orthopaedic Department, Kaiser Permanente Medical Group, 4647 Zion Avenue, San Diego, California 92120
Andrea Cracchiolo, III, M.D.: Department of Orthopaedic Surgery, University of California, Los Angeles School of Medicine, Center for the Health Sciences, Box 956902, Los Angeles, California 90095