A plaster cast was applied for 3 weeks after surgery; the patient did not need any walking aid. Physiotherapy was started after cast removal. The patient's pain was relieved within 4 postoperative days. At 9 months' followup, his symptoms and the mass had completely disappeared.
The use of biodegradable interference screws in ACL reconstruction has gained popularity [7, 13]. They typically are made from poly-L-lactic acid and offer similar or superior fixation [11, 21] in comparison to that of similarly designed metal screws for ACL reconstruction [16, 17]. Comparative studies between biodegradable and metallic screws have shown no superiority of one over the other in terms of pain, Lachman and pivot shift tests, Tegner activity level, and Lysholm score [12, 13, 15, 17]. Biodegradable screws have several advantages over metallic screws: they do not have to be removed, they may avoid the damage metallic screws can cause to the patellar bone/tendon graft in the tunnel, and they avoid metal artifacts with imaging. The benefits of biodegradable screws, however, come with more complications. The reported complications of biodegradable screws are osteolysis around the screw , allergic reaction , and extraarticular pretibial sterile abscess . Other reported complications are transcutaneous  and intraarticular migration , recurrent pretibial ganglion cyst formation , and intraarticular granuloma formation .
There is disagreement among pathologists regarding whether a fibroxanthoma represents a true neoplasm [3, 6], developmental defect , or reactive process . Radiographic findings generally are nondiagnostic. Histologic findings of fibroblasts and mononuclear or multinucleated lipid-filled cells having the appearance of histiocytes with abundant vacuolated cytoplasm interspersed with fibrovascular septations and masses of cholesterol suggest the diagnosis . Cells are negative for S-100 protein and positive for anti-human macrophage marker HAM-56, which indicates histiocyte lineage [3, 5, 10].
Use of bioabsorbable screws for fixation of graft in ACL reconstruction is effective in terms of fixation strength [7, 21] and safe with overall low complication rates ; however, we need to be aware of potential complications, early recognition of which may prevent associated morbidity.
1. Bago-Granell, J., Aguirre-Canyadell, M., Nardi, J. and Tallada, N. Malignant fibrous histiocytoma of bone at the site of a total hip arthroplasty: a case report. J Bone Joint Surg Br.
1984; 66: 38-40.
2. Baums, MH., Zelle, BA., Schultz, W., Ernstberger, and Klinger, HM. Intraarticular migration of a broken screw after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc.
2006; 14: 865-868. 10.1007/s00167-006-0049-2
3. Bertoni, F., Unni, KK., McLeod, RA. and Sim, FH. Xantoma of bone. Am J Clin Pathol.
1988; 90: 377-384.
4. Busfield, BT. and Anderson, LJ. Sterile pretibial abscess after anterior cruciate reconstruction from biodegradable interference screws: a report of 2 cases. Arthroscopy.
2007; 23: 911-e4.
5. Clarke, BE., Xipell, JM. and Thomas, DP. Benign fibrous histiocytoma of bone. Am J Surg Pathol.
1985; 9: 806-815. 10.1097/00000478-198511000-00004
6. Destouet, JM., Kyriakos, M. and Gilula, LA. Fibrous histiocytoma (fibroxanthoma) of a cervical vertebra: a case report with a review of the literature. Skeletal Radiol.
1980; 5: 241-246. 10.1007/BF00580597
7. Dujardin, J., Vandenneucker, H. and Bellemans, J. Tibial cyst and intra-articular granuloma formation after anterior cruciate ligament reconstruction using polylactide carbonate osteoconductive interference screws. Arthroscopy.
2008; 24: 238-242. 10.1016/j.arthro.2007.11.009
8. Haag, M. and Adler, CP. Malignant fibrous histiocytoma in association with hip replacement. J Bone Joint Surg Br.
1989; 71: 701.
9. Hughes, AW., Sherlock, DA., Hamblen, DL. and Reid, R. Sarcoma at the site of a single hip screw: a case report. J Bone Joint Surg Br.
1987; 69: 470-472.
10. Kargi, E., Gungor, E., Verdi, M., Kuiacogiu, S., Erdogan, B., Alli, N. and Altunkaya, SA. Atypical fibroxanthoma and metastasis to the lung. Plast Reconstr Surg.
2003; 111: 1760-1762. 10.1097/00006534-200304150-00032
11. Kousa, P., Jarvinen, TL., Kannus, P. and Jarvinen, M. Initial fixation strength of bioabsorbable and titanium interference screw in anterior cruciate ligament reconstruction: biomechanical evaluation by single cycle and cyclic loading. Am J Sports Med.
2001; 29: 420-425.
12. Lajtai, G., Schmiedhuber, G., Unger, F., Aitzetmuller, G., Klien, M., Noszian, I. and Orthner, E. Bone tunnel remodeling at the site of biodegradable interference screws used for anterior cruciate ligament reconstruction: 5-year follow up. Arthroscopy.
2001; 17: 597-602. 10.1053/jars.2001.21535
13. Laxdal, G., Kartus, J., Eriksson, BI., Faxen, E., Sernert, N. and Karlsson, J. Biodegradable and metallic interference screws in anterior cruciate ligament reconstruction surgery using hamstring tendon grafts: prospective randomized study of radiographic results and clinical outcome. Am J Sports Med.
2006; 34: 1574-1580. 10.1177/0363546506288014
14. Macdonald, D., Fornasier, V. and Holtby, R. Benign fibrohistocytoma (xanthomatous variant) of the acromion: a case report and review of the literature. Arch Pathol Lab Med.
2002; 126: 599-601.
15. Mastrokalos, DS. and Paessler, HH. Allergic reaction to biodegradable interference poly L-lactic acid screws after anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft. Arthroscopy.
2008; 24: 732-733. 10.1016/j.arthro.2006.12.029
16. McGuire, DA., Barber, FA., Elrod, BF. and Paulos, LE. Bioabsorbable interference screws for graft fixation in anterior cruciate ligament reconstruction. Arthroscopy.
1999; 15: 463-473. 10.1053/ar.1999.v15.015046001
17. Plominski, J., Borcz, K., Kwiatkowski, K. and Zabicka, M. Fixation of patellar tendon bone graft in reconstruction of patellar ligaments: comparison of bioabsorbable and metal interface screws—results of treatment. Ortop Traumatol Rehabil.
2008; 10: 44-53.
18. Sassmannshausen, G. and Carr, CF. Transcutaneous migration of a tibial bioabsorbable interference screw after anterior cruciate ligament reconstruction. Arthroscopy.
2003; 19: 133-136. 10.1016/j.arthro.2003.09.017
19. Sekiya, JK., Elkousy, HA. and Fu, FH. Recurrent pretibial ganglion cyst formation over 5 years after anterior cruciate ligament reconstruction. Arthroscopy.
2004; 20: 317-321. 10.1016/j.arthro.2003.11.041
20. Tsuda, E., Ishibashi, Y., Tazawa, K., Sato, H., Kusumi, T. and Toh, S. Pretibial cyst formation after anterior cruciate ligament reconstruction with a hamstring tendon autograft. Arthroscopy.
2006; 22: 691-e6.
21. Weimann, A., Rodieck, M., Zantop, T., Hassenpflug, J. and Petersen, W. Primary stability of hamstring graft fixation with biodegradable suspension versus interference screws. Arthroscopy.
2005; 21: 266-274. 10.1016/j.arthro.2004.10.011
22. Zantop, T., Weimann, A., Schmidtko, R., Herbort, M., Raschke, MJ. and Peterson, W. Graft laceration and pullout strength of soft-tissue anterior cruciate ligament reconstruction: in vitro study comparing titanium, poly-d, l-lactide and poly-d, l-lactide-tricalcium phosphate screws. Arthroscopy.
2006; 22: 1204-1210. 10.1016/j.arthro.2006.06.015