Tibial portal placement: the radiographic correlate of the anatomic safe zone

Comparison of insertional trauma between suprapatellar and infrapatellar portals for tibial nailing

The purpose of this study was to determine differences in insertional articular trauma in infrapatellar tibial portal and suprapatellar portal intramedullary tibial nail insertion techniques. A cadaveric study was performed on 10 matched pairs of fresh-frozen adult cadaver lower extremities with intact extensor mechanisms. Two study groups with 10 limbs each were created: left lower limbs were treated with a standard medial parapatellar nailing portal and right lower limbs were treated with a suprapatellar tibial nailing portal. Start points were created under fluoroscopic guidance in anteroposterior and mediolateral planes. A start wire was placed and opening reaming was performed on the specimens using instrumentation specific to the nailing portal. Specimens were then dissected by medial parapatellar arthrotomy, revealing the intra-articular condition of the knee structures. The border of the tibial entry reamer hole was measured to the anterior horns of the menisci, anterior cruciate ligament root, and intermeniscal ligament using a digital caliper accurate to 0.02 mm. The structure was considered damaged if the structure was obviously damaged on visual inspection or if a measurement was less than 1 mm. Impact to intra-articular structures was numerically lower in the suprapatellar group (2/10) compared with the infrapatellar group (4/10), but the difference was not statistically significant between the 2 groups (P=.629). The suprapatellar portal approach to the tibial start point demonstrated a lower overall incidence of damage to intra-articular structures, but no significant statistical difference existed between the 2 treatment groups.

Quantification of anterior cortical bone removal and intermeniscal ligament damage at the tibial nail entry zone using parapatellar and retropatellar approaches

OBJECTIVES

Anterior cortical bone removal at the tibial nail entry zone has been shown to alter biomechanical properties of the proximal tibia. However, no study has quantified the amount of bone removed. The purpose of this study was to quantify the amount of anterior bone removed at the nail entry zone and assess damage to adjacent intra-articular structures using both parapatellar and retropatellar techniques.

METHODS

The study was performed using 36 cadaveric knees (18 medial parapatellar and 18 retropatellar approaches). A guide pin was placed in the anatomic safe zone using fluoroscopic guidance and a 12.5-mm entry reamer used to open medullary canal. Soft tissues were removed, damage to intra-articular structures recorded, and size of osseous defect created in proximal tibia measured.

RESULTS

The surface area of bone removed with portal creation was not significantly larger with retropatellar (228.4 ± 38.1 mm) versus parapatellar technique (207.9 ± 33.4 mm(2); P = 0.108). This was substantially different than if the entry hole was perfectly round (122.7 mm(2)). No knee went without some damage to intra-articular structures using the parapatellar technique, as opposed to 33% knees with retropatellar technique (P = 0.019). Intermeniscal (IM) ligament was damaged in 83% parapatellar and 56% retropatellar knees (P = 0.146).

CONCLUSIONS

A substantial amount of anterior bone is removed during nail entry portal creation using both parapatellar and retropatellar techniques. Intra-articular structure damage, most commonly IM ligament disruption, was also found to occur at a lower rate with retropatellar technique. Avoidance of both anterior bone removal and IM ligament damage may not be possible because of size and geometrical constraints.

Problems, tricks, and pearls in intramedullary nailing of proximal third tibial fractures

Proximal third tibial shaft fractures have been notoriously difficult to treat. Early reports resulting in high rates of malunion and fixation failure trended surgeons to move away from intramedullary nailing as definitive treatment. However, with the advent of a deepened understanding of the surround anatomy, several techniques have been developed to help maintain proper alignment without early failure or malunion. This review provides a concise update on the tips, tricks, and pearls available in achieving a stable well-aligned construct when definitively treating proximal third tibial shaft fractures via intramedullary nail.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Anterior knee pain after tibial intramedullary nailing using a medial paratendinous approach

OBJECTIVES

To determine the incidence, severity, and etiology of anterior knee pain after tibial intramedullary (IM) nailing using a medial paratendinous approach and to investigate the association between anterior knee pain and functional impairment.

DESIGN

Retrospective study with current clinical and radiographic assessments.

SETTING

Level I trauma center.

PATIENTS

Forty-five patients with unilateral, tibial diaphyseal fractures treated with tibial IM nailing between August 2005 and January 2009. The mean follow-up was 22.3 months (range, 12-52 months).

INTERVENTION

All patients underwent tibial IM nailing using a medial paratendinous approach.

MAIN OUTCOME MEASUREMENTS

Anterior knee pain based on a visual analog scale and functional outcomes based on the Tegner activity score and the modified Lysholm score.

RESULTS

Of the 45 patients, 16 (36%) were painless (N group), 16 (36%) had mild pain (M group), and 13 (28%) had moderate to severe pain (MS group). No group differences were found with respect to age, sex, body mass index, mode of injury, or type of fracture. With regard to nail prominence, superior nail prominence was greater in the MS group than in the other two groups (P = 0.042). There were no significant differences among the three groups in terms of anterior nail prominence (P = 0.221). The nail-apex distance in the MS group was significantly greater than in the other two groups (P = 0.033), and no significant difference was found between the N and M groups. The descending order of the activities with respect to severity of knee pain was kneeling, squatting, running, and stair ascending. Visual analog scale analysis revealed that the MS group had significantly more severe pain for all eight activities examined than the M group. At latest follow-up, the Tegner activity score was significantly lower in the MS group than in the other two groups (P = 0.008), and there were statistically significant intergroup differences in the modified Lysholm score (P < 0.001).

CONCLUSION

Anterior knee pain after tibial IM nailing using a medial paratendinous approach was a frequent complication that was not uncommonly moderate to severe (28%) in Asian patients. Although the etiology of anterior knee pain is undoubtedly multifactorial, it may be related to nail prominence. Furthermore, the severity of anterior knee pain was significantly associated with functional outcome.

LEVEL OF EVIDENCE

Therapeutic Level IV. See page 128 for a complete description of levels of evidence.

Intramedullary nailing of extra-articular proximal tibia fractures

Tibial fractures are the most common long bone fractures. Extra-articular proximal tibia fractures account for approximately 5% to 11% of all tibial shaft fractures. The benefits of intramedullary nailing of these fractures include load sharing, sparing of the extraosseous blood supply, and avoidance of additional soft-tissue dissection, thereby minimizing the risk of postoperative complications. A significant rate of malalignment has been reported with intramedullary nailing of proximal tibia fractures, however. Malalignment typically presents as apex anterior and valgus angulation. Several nailing methods and reduction techniques have been developed to minimize this complication, including the use of a proper starting point and insertion angle, blocking screws, unicortical plates, a universal distractor, and alternative positioning and approaches. Use of one or more of these techniques has resulted in a reported average malreduction rate of 8.2%.

Retropatellar technique for intramedullary nailing of proximal tibia fractures: a cadaveric assessment

OBJECTIVE

To investigate if the radiographically correct and anatomically safe starting point and the appropriate sagittal plane vector could be obtained using a retropatellar technique for proximal tibia fractures treated with an intramedullary device.

METHODS

We performed a cadaveric and radiographic study utilizing 16 limbs. We performed a retropatellar approach via longitudinal quadriceps split, passed a specialized trocar through the patellofemoral joint and onto the superior aspect of the tibia, and inserted Kirschner wires into the anatomic safe zone of the tibial plateau at 0, 10, 20, 30, 40, and 50 degrees of knee flexion utilizing biplanar fluoroscopy. We recorded knee flexion with a goniometer and the entrance vector of the Kirschner wire in relation to the anterior tibial cortex.

SETTING

University-affiliated cadaver and anatomy laboratory.

RESULTS

There was a progressive increase in the ability to obtain the correct anatomical start site from 1 of 16 (6.25%) at full extension to 12 of 16 (75%) at 50 degrees of knee flexion (P = 0.00098). A statistically significant decrease in the average sagittal plane entrance vector in relation to the anterior tibial cortex was found from 23.1 degrees at full extension to -0.41 degrees at 50 degrees of knee flexion (P < 0.0001).

CONCLUSIONS

The retropatellar technique allows the radiographically defined correct start site to be localized, particularly at higher degrees of knee flexion. More favorable intramedullary nail insertion angles were possible with the retropatellar technique, particularly with knee flexion angles greater than 20 degrees. The retropatellar technique demands further investigations to further delineate its advantages, limitations, and possible risks to local anatomy.

The retropatellar portal as an alternative site for tibial nail insertion: a cadaveric study

OBJECTIVE

To define spatial relationships between major intra-articular structures of the knee and the entry site of a tibial nail inserted using a retropatellar portal.

DESIGN

Cadaveric study using 16 fresh-frozen limbs.

SETTING

University-affiliated cadaver and anatomy laboratory.

RESULTS

The mean distance of the nail entry site and the medial and lateral menisci were 6.6 ± 3.2 mm and 6.4 ± 4.4 mm, respectively. The distance to the medial and lateral articular surfaces were 5.6 ± 3.6 mm and 7.4 ± 4.2 mm, respectively. The mean distance to the anterior cruciate ligament footprint was 7.5 ± 3.5 mm. The lateral meniscus was never injured during the procedure. The anterior cruciate ligament was undisturbed in all specimens. The medial meniscus was injured 1 to 2 mm in 12.5% of specimens. The intermeniscal ligament was injured 1 to 2 mm in 81.2% of the specimens.

CONCLUSION

The intermeniscal ligament and medial meniscus are at the most risk during intramedullary nailing of the tibia using the retropatellar technique. This may be corrected by avoiding an excessively medial start point. Damage to the intermeniscal ligament and medial meniscus occurs more commonly with the retropatellar portal, but this damage was never more than 1 to 2 mm. This risk, however, appears similar to the pattern and incidence of injury that occurred in prior studies investigating tibial nail insertion through a standard patellar tendon approach. The retropatellar technique demands clinical investigation to further define both its safety and its use.

The clamshell osteotomy: a new technique to correct complex diaphyseal malunions: surgical technique

BACKGROUND

The treatment of complex diaphyseal malunions is challenging, requiring extensive preoperative planning and precise operative technique. We have developed a simpler method to treat some of these deformities.

METHODS

Ten patients with complex diaphyseal malunions (including four femoral and six tibial malunions) underwent a clamshell osteotomy. The indications for surgery included pain at adjacent joints and deformity. After surgical exposure, the malunited segment was transected perpendicular to the normal diaphysis proximally and distally. The transected segment was again osteotomized along its long axis and was wedged open, similar to opening a clamshell. The proximal and distal segments of the diaphysis were then aligned with use of an intramedullary rod as an anatomic axis template and with use of the contralateral extremity as a length and rotation template. The patients were assessed clinically and radiographically at a mean of thirty-one months (range, six to fifty-two months) after the osteotomy.

RESULTS

Complete angular correction was achieved in each case; the amount of correction ranged from 2° to 20° in the coronal plane, from 0° to 32° in the sagittal plane, and from 0° to 25° in the axial plane (rotation). Correction of length ranged from 0 to 5 cm, and limb length was restored to within 2 cm in all patients. All osteotomy sites were healed clinically by six months. While no deep infections occurred, superficial wound dehiscence occurred in two patients along the approach for the longitudinal portion of the osteotomy, emphasizing the importance of careful soft-tissue handling and patient selection.

CONCLUSIONS

The clamshell osteotomy provides a useful way to correct many forms of diaphyseal malunion by realigning the anatomic axis of the long bone with use of a reamed intramedullary rod as a template. This technique provides an alternative that could decrease preoperative planning time and complexity as well as decrease the need for intraoperative osteotomy precision in a correctly chosen subset of patients with diaphyseal deformities.

LOCALIZATION OF THE TIBIAL ENTRY POINT

Objective: To assess the intramedullary nail entry point in the proximal region of the tibia, through a questionnaire. Methods: 230 participants undergoing treatment for tibial fractures were interviewed. The questionnaire was created with three sections that could be answered in a ”Yes” or “No” format and a fourth section that had two figures representing anteroposterior (AP) and lateral view x-rays that could be answered in an “A, “B” or “C” format. Results: The most frequent reason was “ease of access” (67.8%), followed by “better nail insertion access” (60.9%) and, in third place, “to prevent knee pain” (27.4%). The reasons for choosing the access so as to “prevent knee pain” and “avoid tendinitis” had a significant relationship with points “A” and “C” of the schematic AP x-ray figure, especially “C” (medial tibial crest). There were no significant differences between the types of access to the patellar ligament in the schematic AP and lateral x-ray figures between age groups. Conclusion: The greater the age was, the larger the proportion choosing the question “to avoid valgus deformity” was. The reasons from a medical (practical) perspective related to the type of access in the transpatellar ligament, while the reasons from a patient (functional) perspective related to medial parapatellar access. Transpatellar access was chosen by most of the participants (66.5%).

Three-dimensional analysis of the intramedullary canal axis of tibia: clinical relevance to tibia intramedullary nailing

INTRODUCTION

The aim of this study was to evaluate the appropriate insertion point for a tibial intramedullary nail by measuring the intramedullary canal axis of the tibia in three dimensions.

METHODS

Forty-three pairs (14 males and 29 females) of cadaveric low extremities (mean age 51 years, range 21-60 years) were analyzed to evaluate the appropriate insertion point for a tibial intramedullary nail by measuring the intramedullary canal axis of the tibia in three dimensions. Computed tomography was performed on 86 lower extremities from the hip to the ankle on cadavers. The location of the intramedullary canal axis of the tibia passing through the tibial plateau, the canal axis center (CAC), was measured. The correlations between the lateral tibial spine (LTS) and the mediolateral coordinates of the CAC were analyzed.

RESULTS

The CAC was located at 56.5% distance from the medial cortex. On average, the CAC was located 1.1 mm medial from the LTS. The mean length from the surface center to the CAC was lateral 4.5 mm.

CONCLUSION

The appropriate insertion point for a tibial nail was the slightly medial aspect of the LTS. However, it led to the point with a broad range, increasing the necessity to take individual variations into consideration.

Proximal tibiofibular joint pain after insertion of a tibial intramedullary nail: two case reports with accompanying computed tomography and cadaveric studies

Intramedullary nail (IMN) fixation is a proven, efficient, and effective surgical intervention for diaphyseal tibia fractures. We present a case report of two patients who sustained diaphyseal tibial fractures, were treated with IMN fixation, and subsequently developed lateral and posterolateral knee pain secondary to interlocking screw penetration into the proximal tibiofibular joint (PTFJ). We performed a retrospective radiographic review of 50 consecutive knee computed tomographic scans to define the fibula's respective anatomic relationship to the tibia on axial computed tomographic images in addition to a cadaveric study of four IMN implants to evaluate the orientation of the medial inserted proximal oblique interlock screw with three-dimensional reconstructive fluoroscopy. The "danger zone" was found to be from 44.7 degrees to 72.1 degrees on the right and from 40.6 degrees to 73.0 degrees on the left. The cadaveric computed tomographic study showed the projected screw placement angles to be 45 degrees for the Synthes IMN, 45 degrees for the Stryker IMN, 48 degrees for the DePuy IMN, and 63 degrees for the Smith & Nephew IMN. These findings were correlated to an anatomically based "clock face" guide. To our knowledge, this report is the first to illuminate a PTFJ injury with the initial presenting complaint of lateral and posterolateral knee pain from a medially inserted proximal oblique interlocking screw after IMN for a diaphyseal tibia fracture. Using the proposed reproducible "clock face" diagram and understanding the computed tomography-derived PTFJ "danger zone" for placement of proximal oblique interlock screws for IMN fixation of tibia fractures, surgeons can avoid violation of the PTFJ.

Influence of medial parapatellar nail insertion on alignment in proximal tibia fractures--special consideration of the fracture level

INTRODUCTION

Although a lateral starting point for tibial nailing is recommended to avoid valgus misalignment, higher rates of intra-articular damage were described compared with a medial parapatellar approach. The aim of this anatomic study was to evaluate the fracture level allowing for a safe medial nail entry point without misalignment or dislocation of fragments.

MATERIALS AND METHODS

Thirty-two fresh-frozen cadaver lower extremities were used to create 1-cm osteotomies at four different levels (n = 8) from 2 cm to 8 cm below the tibial tuberosity. Nine-millimeter unreamed solid titanium tibial nails (Connex, I.T.S. Spectromed, Lassnitzhohe, Austria) were inserted from a medial parapatellar incision. Misalignment (degree) and dislocation of the distal fragment were measured in the frontal and sagittal plane.

RESULTS

A medial parapatellar approach for tibial nail insertion mainly caused valgus and anterior bow misalignment and ventral and medial fragment displacement. Mean misalignment and fragment displacement did not exceed 0.5 degree if the osteotomy was performed 8 cm to 9 cm below the tibial tuberosity.

DISCUSSION

According to the results of this study, a medial parapatellar approach can be performed without misalignment and fragment dislocation in proximal tibia fractures extending 8 cm or more below the tibial tuberosity.

The clamshell osteotomy: a new technique to correct complex diaphyseal malunions

BACKGROUND

The treatment of complex diaphyseal malunions is challenging, requiring extensive preoperative planning and precise operative technique. We have developed a simpler method to treat some of these deformities.

METHODS

Ten patients with complex diaphyseal malunions (including four femoral and six tibial malunions) underwent a clamshell osteotomy. The indications for surgery included pain at adjacent joints and deformity. After surgical exposure, the malunited segment was transected perpendicular to the normal diaphysis proximally and distally. The transected segment was again osteotomized along its long axis and was wedged open, similar to opening a clamshell. The proximal and distal segments of the diaphysis were then aligned with use of an intramedullary rod as an anatomic axis template and with use of the contralateral extremity as a length and rotation template. The patients were assessed clinically and radiographically at a mean of thirty-one months (range, six to fifty-two months) after the osteotomy.

RESULTS

Complete angular correction was achieved in each case; the amount of correction ranged from 2 degrees to 20 degrees in the coronal plane, from 0 degrees to 32 degrees in the sagittal plane, and from 0 degrees to 25 degrees in the axial plane (rotation). Correction of length ranged from 0 to 5 cm, and limb length was restored to within 2 cm in all patients. All osteotomy sites were healed clinically by six months. While no deep infections occurred, superficial wound dehiscence occurred in two patients along the approach for the longitudinal portion of the osteotomy, emphasizing the importance of careful soft-tissue handling and patient selection.

CONCLUSIONS

The clamshell osteotomy provides a useful way to correct many forms of diaphyseal malunion by realigning the anatomic axis of the long bone with use of a reamed intramedullary rod as a template. This technique provides an alternative that could decrease preoperative planning time and complexity as well as decrease the need for intraoperative osteotomy precision in a correctly chosen subset of patients with diaphyseal deformities.

Operative treatment of ipsilateral noncontiguous unicondylar tibial plateau and shaft fractures: combining plates and nails

Unicondylar plateau fractures with ipsilateral noncontiguous tibial shaft fractures are rare injuries; over a 10-year period, we identified only 50 of these combined injuries in our series of 1586 tibial fractures. Modern locking plates and percutaneous techniques have been increasingly indicated for this injury pattern though this technique can compromise optimal fixation of the plateau and/or shaft fractures. For a number of years, we have combined intramedullary nails and plates for the treatment of these fractures with excellent results. With careful attention to some technical points, ipsilateral tibial plateau and shaft fractures can be managed successfully by combining 2 familiar techniques commonly employed for each injury in isolation.

Open diaphyseal long bone fractures: a reduction method using devitalized or extruded osseous fragments

Open diaphyseal and meta-diaphyseal fractures of the lower extremity remain therapeutically challenging. Currently accepted treatment methods consist of a thorough irrigation and debridement of nonviable tissue combined with locked intramedullary nailing. Although exact reduction parameters remain controversial, achievement of a satisfactory reduction becomes increasingly difficult with fracture comminution and overt bone loss. We describe the simple technique of using multiple associated devitalized tibial bone fragments to obtain an accurate reduction prior to intramedullary nailing. This technique can be extended to other long bone fractures.

Knee pain after tibial nailing: the role of nail prominence

We analyzed the relationship between knee pain after tibial nailing and nail prominence. We identified 70 patients in our trauma registry with healed fractures initially treated with intramedullary nails. Subjective pain and function were measured with visual analog pain scales and Lysholm knee scores at a mean of 20 months after fracture. These scores were compared with nail prominence measured on postoperative radiographs. More than 49% of patients had knee pain. Subjective knee pain was more common in women and patients with a smaller plateau width. Anterior nail prominence was associated with increased pain at rest. Patients with superior nail prominence had increased pain with kneeling and walking. Nail prominence correlated with increased knee pain. We think surgeons can decrease, but not eliminate, the severity of knee pain after tibial nailing by burying the tip of the nail as reflected on lateral radiographs.

LEVEL OF EVIDENCE

Prognostic Study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Computed tomography-guided and arthroscopically controlled en bloc retrograde resection of a juxta-articular osteoid osteoma of the tibial plateau

Osteoid osteoma represents approximately 10% to 11% of all the benign bone tumors. The localization at the articular and juxta-articular level of the knee is an atypical picture that causes both diagnostic and therapeutic problems. We present the case of an osteoid osteoma of the lateral tibial plateau just beneath the joint level. The lesion was removed by a rear-entry computed tomography (CT)-guided drill under arthroscopic control and the bony defect filled with bone graft harvested from the proximal tibial metaphysis. Postoperative CT scans at 3 months, and 1 and 2 years were performed. The result of the kneeling test to evaluate donor-site morbidity 1 year after the surgery was negative. There were no immediate or delayed complications. Currently (2 years postoperatively), the patient has no pain and has gone back to his normal active daily lifestyle and routines. The follow-up CT scan 2 years after surgery showed complete excision of the lesion and perfect positioning of the bone graft. This new approach/technique enabled us to avoid damaging the proximal structures, to examine the lesion, and to fill the bony defect. Moreover, as shown by CT scan at follow-up, iatrogenic lesions to the cartilage of the tibial plateau were not reported.

Anterior knee pain and thigh muscle strength after intramedullary nailing of tibial shaft fractures: a report of 40 consecutive cases

OBJECTIVES

Chronic anterior knee pain is a common complication following intramedullary nailing of a tibial shaft fracture. The source of pain is often not known nor is the reason for a simultaneous decrease in thigh muscle strength. Anterior knee pain has also been reported following an anterior cruciate ligament rupture. No previous investigation has assessed whether weakness of the thigh muscles is associated with anterior knee pain following intramedullary nailing of tibial shaft fractures.

DESIGN

Prospective study.

SETTING

University Hospital of Tampere, University of Tampere.

PATIENTS

Fifty consecutive patients with a nailed tibial shaft fracture were initially included in the study. Ten patients did not have isokinetic strength testing for various reasons and were eliminated from the study.

MAIN OUTCOME MEASUREMENTS

Isokinetic muscle strength measurements were done in 40 patients at an average 3.2 +/- 0.4 (SD) years after nail insertion (1.7 +/- 0.3 years after the nail extraction).

RESULTS

Twelve (30%) patients were painless and 28 (70%) patients had anterior knee pain at follow-up. With reference to the hamstrings muscles, the mean peak torque deficit of the injured limb (as compared with the uninjured limb) was 2 +/- 11% in the painless group and 11 +/- 17% in the pain group at a speed of 60 degrees /s (P = 0.09, [95% CI for the group difference = -18% to 0%]). At a speed of 180 degrees /s, the corresponding deficits were -3 +/- 13% and 10 +/- 21% (P = 0.03, [95% CI for the group difference = -4% to -2%]). With reference to the quadriceps muscles, the mean peak torque deficit of the injured limb was 14 +/- 15% in the painless group and 15 +/- 15% in the pain group at speed of 60 degrees /s (P = 0.71, [95% CI for the group difference = -11% to 10%]). At a speed of 180 degrees /s, the corresponding deficits were 9 +/- 11% and 14 +/- 17% (P = 0.46, [95% CI for the group difference = -14% to 5%]).

CONCLUSION

Based on this prospective study, we conclude that anterior knee pain after intramedullary nailing of a tibial shaft fracture, although of multifactorial origin, may be related to deficiency in the flexion strength of the thigh muscles.

Incision placement for intramedullary tibial nailing: an anatomic study

OBJECTIVES

For intramedullary nailing of tibial shaft fractures, a recent study has determined that the entry site should be just medial to the lateral tibial spine at the anterior margin of the articular surface. Gaining access to this site is often through a medial parapatellar or transpatellar approach. Several studies have indicated that a transpatellar approach may contribute to anterior knee pain. Our study sought to use anatomic measurement to determine the ideal incision site for insertion of an intramedullary tibial nail. DESIGN Part I: survey of Orthopaedic Trauma Association (OTA) members. Part II: anatomic study.

SETTING

A Level I trauma center in Sacramento, California.

PARTICIPANTS

Part I: OTA members. Part II: a group of 56 healthy volunteers.

INTERVENTION

Part I: questionnaire sent to OTA members. Part II: clinical examination and radiographic analysis.

MAIN OUTCOME MEASUREMENTS

Part I: responses to questionnaire. Part II: anatomic measurements.

RESULTS

Part I: based on a questionnaire, OTA members use at least one or more approaches to access their preferred tibial nail entry site. Fifty-seven percent use only one type of approach in all cases. Part II: the authors performed a clinical and radiographic study in 56 volunteers (112 knees) to determine the relationship of the lateral tibial spine to the patellar tendon. On the basis of this information, the tendon was divided into thirds to account for the three most common surgical approaches. The entry site was in the lateral zone in 29 knees, the middle zone in 75 knees, and the medial zone in 8 knees. If divided equally into purely a medial or lateral zone to avoid a transpatellar approach, the starting point fell into the medial zone in 42 knees and the lateral zone in 70 knees.

CONCLUSIONS

Individual variations in patellar tendon anatomy should be considered when choosing the proper entry site for tibial nailing. Based on the assumption that the ideal entry point for tibial nailing is just medial to the tibial spine at the anterior margin of the articular surface, a preoperative fluoroscopic measurement before incision can guide the surgeon as to whether a medial parapatellar, transpatellar, or lateral parapatellar approach provides the most direct access to this entry site. The routine use of a single approach for all tibial nails may no longer be justified.