CT scan analysis of implant mating comparing APA versus TEA in simultaneous bilateral TKA: One technique per knee.

BACKGROUND: The optimal landmark for setting femoral component rotation in primary TKA remains a debate. This study compares the Anterior-Posterior Axis (APA) versus the Transepicondylar Axis (TEA) in patients undergoing simultaneous bilateral TKA, where one reference line was randomized to each knee. Implant mating was assessed via post-operative CT scans. METHOD: The study included 32 patients with osteoarthritis in both knees with similar varus deformities. All patients underwent the same surgical procedure on both knees, aside from the selected femoral rotation axis line: APA randomized to one side and TEA to the contralateral. Post-operative CT scans were performed in extension to assess in-vivo mating. RESULTS: CT scan analysis showed mean rotation of the femoral implant externally rotated relative to the radiographic TEA with no significant difference between the APA and TEA groups (p = 0.28). Tibial implant rotation was also externally rotated to the radiographic TEA with no significant difference (p = 0.59). Femoral-tibial implant mating showed a mean external rotation of the tibia relative to the femur in both groups: 0.86 ± 4.0° external rotation in the APA group and 0.23 ± 3.7° external rotation in the TEA group. There was no significant difference between groups (p = 0.52). The range of mating mismatch was 15° in the APA group and 16.5° in the TEA group. CONCLUSIONS: When using a measured resection, posterior referencing technique, post-operative femoral-tibial implant mating measured by CT scan showed no superiority comparing the APA method versus the TEA method. LEVEL OF EVIDENCE: 2 Randomized prospective study.

Both low and high knee flexion angles during tibial graft fixation yield comparable outcomes following ACL reconstruction with quadriceps tendon autograft: A systematic review.

IMPORTANCE: A paucity of clinical evidence surrounds the effect of the knee flexion angle during tibial fixation of the graft during anterior cruciate ligament (ACL) reconstruction. While biomechanical studies have recently sought to revive this area of study in both single- and double-bundle graft populations, they have done so using variants of the hamstring graft. This does not shed light on the optimal fixation of other autograft options, namely, the quadriceps tendon (QT) autograft. OBJECTIVES: To determine the effect of the knee flexion angle during tibial graft fixation on functional and clinical outcomes following ACL reconstruction using single-bundle QT autograft, inclusive of both soft-tissue and bone-plug graft types. EVIDENCE REVIEW: An electronic search of MEDLINE, EMBASE, Web of Science, and the Cochrane Library was carried out from database inception to June 2020. Following study screening, patient demographics and fixation technique as well as both subjective and objective clinical outcomes were abstracted. Studies were divided based on the knee flexion angle during tibial fixation of the graft. The low knee flexion angle (L-KFA) group included patients with a tibial fixation angle of < 30° of flexion, and the high knee flexion (H-KFA) group included those with a tibial fixation of exactly 30° of flexion. The data were qualitatively synthesized due to significant heterogeneity across the included studies. FINDINGS: Sixteen studies (1,169 patients) were included for analysis. There were 675 patients in the L-KFA group (mean age range, 18.7-34.5 years) and 494 patients in the H-KFA group (mean age range, of 23.2-32.1 years). Both groups yielded statistically significant improvements from preoperative to postoperative scores across several functional and clinical outcomes. Return to pre-injury activity levels ranged from 64% to 81% in L-KFA studies and from 73.3% to 86.7% in H-KFA studies. All-cause graft failure rates ranged from 1.4% to 4.3% in L-FKA studies and from 0%-10.7% in H-KFA studies. CONCLUSION: Both low- and high-knee flexion angles during tibial graft fixation produce improved postoperative clinical and functional outcomes with comparable outcomes across groups. There is inconclusive evidence to recommend the ideal knee flexion angle for graft fixation in primary ACLR. LEVEL OF EVIDENCE: Level IV.

Comparison of Anterior-Posterior Axis Versus Transepicondylar Axis in Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty: One Technique per Knee.

BACKGROUND: In primary total knee arthroplasty (TKA), the preferred reference line for setting femoral component rotation is debatable. This study compared the anterior-posterior axis line (APAL) versus the transepicondylar axis line (TEAL) in patients undergoing simultaneous bilateral TKA using a measured resection technique where one reference line was randomized to each knee. METHODS: This prospective study compared the two reference lines using posterior knee referencing with a cemented posterior stabilized knee. The study included 32 patients with osteoarthritis with both knees having similar varus knee deformities. All patients had the same surgical procedure with the only change being the selected femoral rotation axis line. Patients were followed up for a minimum of two years. RESULTS: There was no significant difference in any of the measured radiographic, operative, and clinical parameters, except for a postoperative radiographic limb alignment (APAL 179.7° vs TEAL 180.1° P = .04). The mean femoral external rotation relative to the posterior condylar axis line (PCAL) was 3.0 degrees (0-7 degrees) using the APAL and 3.3 degrees (2-7 degrees) using the TEAL (P = .46). Two-year knee flexion and revised Oxford Knee Scores showed no difference. Seventy-five percent of patients stated no preference for either knee technique. CONCLUSION: When using a measured resection, a posterior referencing technique, we found no difference in knee function and scores when setting femoral component rotation using the APAL versus TEAL. LEVEL OF EVIDENCE: 2, Randomized prospective study.

Comparison of Gap Balancing vs Measured Resection Technique in Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty: One Technique per Knee.

BACKGROUND: Total knee arthroplasty requires careful surgical technique to attain the goal of a well-aligned and symmetrically balanced knee. Soft tissue balance and correct femoral component rotation are paramount in achieving these goals. The two competing techniques to select femoral component rotation and soft tissue balance are the gap balance technique and the measured resection technique. METHODS: We performed a randomized, prospective study to compare the two techniques in patients undergoing simultaneous bilateral total knee arthroplasty, whereby one technique was performed in each knee. Fifty (50) subjects were enrolled into the study. The inclusion criteria were osteoarthritic varus knee deformities with similar deformities in both knees. Subjects were followed up for a minimum of two years. RESULTS: The knees balanced via the gap balance technique had significantly more posterior medial bone removed from the femur than those knees balanced via the measured resection technique (P < .001). Knees in the gap balance group tended to require more medial knee releases in extension and tended to have smaller sized femoral components as a result of cutting more bone from the femur in flexion. The modular tibial polyethylene bearing tended to be thicker in the gap balance group. Despite these differences, average knee flexion and functional revised Oxford Knee Scores at 2-year follow-up were not statistically different. CONCLUSION: At 2-year follow-up, there were no differences between the function and scores using the two techniques. Long-term follow-up will be necessary to evaluate any differences in long-term durability.

Osteochondral autografts.

The healing potential for articular cartilage lesions is limited due to many physiological, local and mechanical factors. Spontaneous healing of partial- and full-thickness lesions is slow, and subsequent tissue response is usually not durable. In symptomatic, and high-demand, patients, a definitive treatment modality must be offered which allows for a sustained recovery with minimal debilitation. Injuries, which damage the subchondral bone, heal with the formation of fibrocartilage. This tissue fails long-term survival because of its inability to withstand the variable cyclic loads and compression forces that it is subjected to. While regeneration of the damaged cartilage by an entirely new articular surface is a goal beyond current available techniques, repair of the osteochondral defects with normal hyaline cartilage is possible by various options. Osteochondral defects that are larger then 2 cm are best treated by osteochondral autograft technique. The short-term outcomes of the present series show excellent results.