Abstract Based on our clinical ex- perience and an anatomical study, we examined the conditions under which injury to the popliteal artery, tibial nerve or peroneal nerve and its branches may occur during high tib- ial osteotomy. In 250 high tibial os- teotomies performed in our depart- ment, we observed the following in- traoperative complications. (1) The popliteal artery was severed in 1 pa- tient and repaired by the same surgi- cal team using a microsurgical tech- nique. (2) A tibial nerve paresis also occurred in 1 patient. (3) In 3 pa- tients, temporary palsy of the ante- rior tibialis muscle was documented. (4) In 4 other patients, palsy of the extensor hallucis longus occurred. To investigate the causes of these com- plications in the popliteal artery, tib- ial nerve and branches of the pero- neal nerve, we dissected the neu- rovascular structures surrounding the area of the osteotomy in 10 cadav- eric knees and performed a high tib- ial osteotomy in another 13 cadav- eric knees. We concluded the follow- ing. (1) The popliteal artery and tib- ial nerve are protected, at the level of the osteotomy, behind the popliteus and tibialis posterior muscles. Dam- age can occur only by placing the Hohman retractor behind the mus- cles. The insertion of the muscles is very close to the periosteum and can be separated only with a scalpel. (2) The tibialis anterior muscle is inner- vated by a group of branches arising from the deep branch of the peroneal nerve. In two-thirds of the dissected knees, we found a main branch close to the periosteum, which can be damaged by dividing the muscle im- properly or due to improper place- ment and pressure of the Hohman retractor. This may explain the par- tially reversible muscle palsy. (3) The extensor hallucis longus is also innervated by 2–3 thin branches, arising from the deep branch of the peroneal nerve, but in 25% of the specimens, only one large branch was found. This branch is placed un- der tension by manipulating the dis- tal tibia forward. Thus, it may be damaged by the Hohman retractor during distal screw fixation, ten- sioned by hyperextension or directly injured during midshaft fibular os- teotomy. Key words High tibial osteotomy · Distal fibular osteotomy · Neurovascular complications · Common peroneal nerve KNEE Knee Surg, Sports Traumatol, Arthrosc (1999) 7 : 15–19 © Springer-Verlag 1999 Anastasios D. Georgoulis Charalampos A. Makris Christos D. Papageorgiou Ulf G. Moebius Theodoros Xenakis Panagiotis N. Soucacos Nerve and vessel injuries during high tibial osteotomy combined with distal fibular osteotomy: a clinically relevant anatomic study Received: 12 May 1997 Accepted: 12 November 1997 A. D. Georgoulis () · C. A. Makris · C. D. Papageorgiou · U. G. Moebius · T. Xenakis · P. N. Soucacos Department of Orthopaedic Surgery, University of Ioannina Medical School, GR-45110 Ioannina, Greece Tel.: +30-651-74612 or 75674 Fax: +30-651-46222 or 74612