Abstract

INTRODUCTION

Intramedullary nailing is the treatment of choice for the majority of tibial shaft fractures with low rate of complications such as non-union, malunion, joint stiffness and infection.[1,2,3] One of the most common complications of the tibial nailing is chronic anterior knee pain whose incidence has been reported to range from 10% to 86% respectively.[2,4,5] Until date, the etiology of anterior knee pain after intramedullary nailing of tibia is still unknown. Several studies have proposed that a patellar splitting approach for nail insertion is associated with a higher prevalence of anterior knee pain than a medial paratendinous approach.[6,7,8,9,10,11] Some other studies have reported technical causes for the chronic anterior knee pain such as nail or screw prominence, traumatization of the fat pad or patellar tendon, iatrogenic intra-articular damage and neuroma of the infra-patellar branch of the saphenous nerve.[4,12,13,14,15] Moreover, some investigators have blamed post-operative muscle weakness and younger age as other important factors for the post-operative anterior knee pain.[16]

The purpose of this study was to assess demographic issues (such as age, gender), type of the fracture, surgical technique and position of the proximal tip of the nail related to anterior knee pain following tibial nailing.

MATERIALS AND METHODS

All patients with isolated, unilateral, closed or open (Gustilo type I, II, IIIA) tibial shaft fracture who were referred to Kashani University Hospital (Isfahan, Iran) from July 2009 to July 2011 had undergone tibial nailing were identified retrospectively to conduct a cross-sectional study. Patients with the following criteria were included in to the study; 15 years of age or older; extra-articular fracture; absence of any major comorbidities; absence of Gustilo type IIIB and IIIC open fractures. Patients with anesthesia and neuroma around the incision site, superficial or deep infection in the recovery period, nonunion or angular malunion, weakness of quadriceps and hamstring muscles, previous injury to both knees and secondary trauma were excluded from the study.

All the selected patients were called for review and the purpose of the study was explained for them. Demographic data including age, sex and also information about the fracture (open or close fracture), surgery, recovery and post recovery periods were obtained from the medical documents of the patients. Two types of surgery were used: Closed nailing with the use of a patellar tendon-splitting (transtendinous) and closed nailing with the use of a paratendinous approach. In all the patients operations were done within 48 h after injury by trauma surgeons who were expert with these techniques. Intramedullary nailing technique was completed with 2 medial to lateral proximal and 2 medial to lateral distal locking screws and union of the fracture sites were completed. In all the patients the same type of nail were used.

The patients were examined for anterior knee pain, anesthesia and neuroma around the incision site and also, lateral radiographs of both knees were taken. Anterior knee pain was evaluated during rest, walking, running, squatting and kneeling. All the patients were independently examined by two orthopedic experts.

In all the patients, distances from the nail to the tibia plateau and anterior tibial cortex were evaluated in the lateral X-rays according to the definition of Keating et al.[7] On the lateral X-ray, the distance between the two parallel lines, one passing through the tibial plateau and the other through the apex of the nail was defined as the height of the nail. The negative (−) symbol was used to indicate that the nail was below the articular surface and positive (+) to show the extent of nail above the articular surface of tibial plateau. On the same lateral X-ray, anterior cortex-nail distance was defined as the distance between the lines drawn on the anterior cortex of the tibia and the anterior tip of the nail. The positive (+) value was assigned if the nail protruded beyond the cortex and the negative (−) value was assigned if it was deep in the cortex.

RESULTS

According to the medical documents, a total number of 102 patients met our inclusion and exclusion criteria. Seven of them had left the city and were not able to follow-up. Of the 102 patients, 95 were the final population of the study. The mean age of the patients was 33.52 ± 1.62, from among whom 87 (91.6%) were male, 74 (77.9%) had close fracture and 60 (63.2%) had undergone paratendinous method of surgery respectively.

Twenty six (27.4%) of the patients had anterior knee pain. The pain was exacerbated by kneeling in 60% of the participants. Table 1 illustrates the association of knee pain with age, sex, type of fracture (close vs. open) and method of surgery (transtendinous vs. paratendinous). The mean age of the group with knee pain was 32.69 ± 2.78 and 33.84 ± 1.98 in the group without pain, the difference of which was not statistically significant (P = 0.754). We also classified the patients into two groups of older than 33.5 and <33.5 years of age, as the mean age of patients was 33.52 ± 1.62. As you can be seen in Table 1, there was no significant difference between the two age classified groups in the presence of knee pain (P = 0.952). Furthermore, there were no statistically significant differences between the two groups of patients with and without anterior knee pain by sex, type of fracture and type of surgery (P = 0.502, 0.212 and 0.745, respectively).