OTA 1999 Posters

Ability to Kneel after Tibial Nailing: The Length of Incision Matters

Peter Schandelmaier, Privatdozent Dr.; Christian Krettek, Prof., MD; Klaus Wolter; Harald Tscherne, Prof., MD, Trauma Department, Hannover Medical School, Hannover, GERMANY

Purpose: Evaluation of the influence of the length of skin incision at the insertion site and outcome as well as knee pain after tibial nailing.

Methods: Between January 1993 and December 1996, 180 tibial shaft fractures were treated within 24 hrs after the injury at our institution. All tibial nailings were done with the same type of unreamed nail via a patellar tendon-splitting approach without a fracture table. The skin incision was centered in the axis of the tibial shaft with the proximal end of the incision at distal patellar pole. At the index operation OTA fracture classification as well as soft tissue injury were recorded. Thirty-four cases had additional disease or lived outside the country , which left 146 for follow up. Out of these 131 attended the follow-up clinic at least 1 year (mean 17 months, range 12 to 38 months) postoperatively. At the follow-up clinic a validated subjective knee questionnaire (Flandry et al. 1991) was given to the patients. Questions regarding pain and discomfort during kneeling were added. The length of the skin incision at the nail insertion site was measured in 90° of knee flexion. For functional evaluation the Karlström and Olerud Score was used. The projection of the proximal nail tip was measured on anterior-posterior and lateral views of the tibia. Single-way Anova and Kruskal Wallis tests were used for statistical evaluation. A p value of less than 0.05 was considered significant.

Results: The sixty-six patients (48%) had no problems with kneeling, 47 (34%) could kneel only a short time, 26 patients (19%) could not kneel at all. The mean length of skin incision was 3.9 cm (SD 2.5 cm range 1-12 cm). The mean functional score was 32.8 points (SD 3.4 , range 15-36). Mean distance from the proximal nail tip on anterior-posterior view was 7.3 mm below the tibial plateau (SD 11 mm, range 15 mm above ­ 41 mm below the tibial plateau). Mean distance from the proximal nail tip on lateral view was 11 mm below the tibial plateau (SD 12 mm, range 7 mm above ­ 47 mm below the tibial plateau). The ability to kneel without pain was significantly correlated with the skin incision length ( p=0.007, f=5.139) as well as with the functional score (p=0.000, f=16.6). The influence of the position of the nail tip on the ability to kneel was still significant (p=0.013, f=4.463) but less pronounced. Fracture type and soft tissue injury showed no significant influence.

Discussion: While the use of a patellar tendon-splitting approach has been shown to give a higher risk of subsequent knee pain, an influence of the length of skin incision, as shown in our study, has not been previously described. To reduce the inability to kneel, which was significantly correlated with the functional score, care should be taken to minimize the length of the skin incision. As has been previously reported, particular care should be taken to avoid excessive prominence of the nail at the entry site.

Conclusion: To give the patients unrestricted ability to kneel after tibial nailing, the length of the incision should be minimized. An unnecessarily long incision, especially when accompanied by a patellar tendon-splitting approach, might lead to the inability to kneel.