Control of laxity in knees with combined posterior cruciate ligament and posterolateral corner deficiency: comparison of single-bundle versus double-bundle posterior cruciate ligament reconstruction combined with modified Larson posterolateral corner reconstruction

Anatomic Fibular-Based Posterolateral Corner Reconstruction With 2 Femoral Tunnels Shows Lowest Residual Laxity With External Rotation and Varus Stresses: A Systematic Review and Network Meta-analysis of In Vitro Biomechanical Studies

PURPOSE

To perform a systematic review and network meta-analysis of in vitro cadaveric, biomechanical studies evaluating described techniques for posterolateral corner (PLC) reconstruction, including fibular- and tibiofibular-based techniques.

METHODS

The PubMed/MEDLINE, Embase, and Cochrane Library databases were searched in December 2023 for cadaveric studies evaluating PLC reconstruction. After a descriptive summary, a series of frequentist network meta-analyses comparing (1) nonanatomic fibular-based (single femoral tunnel), (2) anatomic fibular-based (double femoral tunnel), and (3) anatomic tibiofibular-based PLC reconstructions with the intact knee were performed for both external rotation (ER) and varus laxity from 0° to 90° of knee flexion. Pooled treatment estimates were calculated as mean differences (MDs) with 95% confidence intervals (CIs) using random-effects models.

RESULTS

A total of 31 studies were included. Nonanatomic fibular-based reconstructions showed increased ER laxity compared with the intact state between 30° and 90° of flexion (MD, 1.66° [95% CI, -0.27° to 3.59°] at 0° [P = .093]; MD, 2.29° [95% CI, 0.44° to 4.13°] at 30° [P = .015]; MD, 3.04° [95% CI, 0.95° to 5.12°] at 60° [P = .004]; and MD, 4.30° [95% CI, 1.41° to 7.19°] at 90° [P = .004]). The anatomic fibular- and tibiofibular-based reconstructions restored ER stability at all flexion values (except at 0° for tibiofibular based). All 3 reconstructions restored varus stability compared with the intact state in all scenarios except the anatomic fibular-based techniques at 0° (MD, 0.85° [95% CI, 0.06° to 1.63°]; P = .034). Across the assessed ER and varus laxity states, the anatomic fibular-based reconstruction was ranked "best" in 5 of 8 scenarios.

CONCLUSIONS

PLC reconstructions using nonanatomic fibular-based techniques showed increased residual laxity in ER from 30° to 90° of knee flexion. Conversely, anatomic fibular- and tibiofibular-based reconstructions showed ER and varus laxity similar to that in the intact knee state across most of the assessed knee flexion values.

CLINICAL RELEVANCE

Various techniques have been described for PLC reconstruction. However, no study has comprehensively compared the biomechanical properties of these reconstructions with one another.

Altered knee kinematics after posterior cruciate ligament single-bundle reconstruction-a comprehensive prospective biomechanical in vivo analysis

Purpose: Passive tibiofemoral anterior-posterior (AP) laxity has been extensively investigated after posterior cruciate ligament (PCL) single-bundle reconstruction. However, the PCL also plays an important role in providing rotational stability in the knee. Little is known in relation to the effects of PCL single-bundle reconstruction on passive tibiofemoral rotational laxity. Gait biomechanics after PCL reconstruction are even less understood. The aim of this study was a comprehensive prospective biomechanical in vivo analysis of the effect of PCL single-bundle reconstruction on passive tibiofemoral rotational laxity, passive anterior-posterior laxity, and gait pattern. Methods: Eight patients undergoing PCL single-bundle reconstruction (seven male, one female, mean age 35.6 ± 6.6 years, BMI 28.0 ± 3.6 kg/m2) were analyzed preoperatively and 6 months postoperatively. Three of the eight patients received additional posterolateral corner (PLC) reconstruction. Conventional stress radiography was used to evaluate passive translational tibiofemoral laxity. A previously established rotometer device with a C-arm fluoroscope was used to assess passive tibiofemoral rotational laxity. Functional gait analysis was used to examine knee kinematics during level walking. Results: The mean side-to-side difference (SSD) in passive posterior translation was significantly reduced postoperatively (12.1 ± 4.4 mm vs. 4.3 ± 1.8 mm; p < 0.01). A significant reduction in passive tibiofemoral rotational laxity at 90° knee flexion was observed postoperatively (27.8° ± 7.0° vs. 19.9° ± 7.5°; p = 0.02). The range of AP tibiofemoral motion during level walking was significantly reduced in the reconstructed knees when compared to the contralateral knees at 6-month follow-up (16.6 ± 2.4 mm vs. 13.5 ± 1.6 mm; p < 0.01). Conclusion: PCL single-bundle reconstruction with optional PLC reconstruction reduces increased passive tibiofemoral translational and rotational laxity in PCL insufficient knees. However, increased passive tibiofemoral translational laxity could not be fully restored and patients showed altered knee kinematics with a significantly reduced range of tibiofemoral AP translation during level walking at 6-month follow-up. The findings of this study indicate a remaining lack of restoration of biomechanics after PCL single-bundle reconstruction in the active and passive state, which could be a possible cause for joint degeneration after PCL single-bundle reconstruction.

A Comprehensive Meta-analysis of Clinical and Biomechanical Outcomes Comparing Double-Bundle and Single-Bundle Posterior Cruciate Ligament Reconstruction Techniques

BACKGROUND

Posterior cruciate ligament (PCL) reconstruction techniques have historically focused on single-bundle (SB) reconstruction of the larger anterolateral bundle without addressing the codominant posteromedial bundle. The SB technique has been associated with residual laxity and instability, leading to the development of double-bundle (DB) reconstruction techniques.

PURPOSE

To perform a meta-analysis of comparative clinical and biomechanical studies to differentiate the pooled outcomes of SB and DB PCL reconstruction cohorts.

STUDY DESIGN

Meta-analysis and systematic review: Level of evidence, 3.

METHODS

Six databases were queried in February 2022 for literature directly comparing clinical and biomechanical outcomes for patients or cadaveric specimens undergoing DB PCL reconstruction against SB PCL reconstruction. Biomechanical outcomes included posterior tibial translational laxity, external rotational laxity, and varus laxity at 30° and 90° of knee flexion. Clinical outcomes included the side-to-side difference in posterior tibial translation during postoperative stress radiographs, risk of a major complication, and the following postoperative patient-reported outcome measures: Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective and objective scores. A random-effects model was used to compare pooled clinical and biomechanical outcomes between the cohorts.

RESULTS

Fifteen biomechanical studies and 13 clinical studies were included in this meta-analysis. The DB group demonstrated significantly less posterior tibial translation at 30° and 90° of knee flexion (P < .00001). Additionally, the DB group demonstrated significantly less external rotation laxity at 90° of knee flexion (P = .0002) but not at 30° of knee flexion (P = .33). There was no difference in varus laxity between the groups at 30° (P = .56) or 90° (P = .24) of knee flexion. There was significantly less translation on stress radiographs in the DB group (P = .02). Clinically, there was no significant difference between the groups for the Lysholm score (P = .95), Tegner score (P = .14), or risk of a major complication (P = .93). DB PCL reconstruction led to significantly higher odds of achieving "normal" or "near normal" objective IKDC outcomes for the included prospective studies (P = .04) and higher subjective IKDC scores (P = .01).

CONCLUSION

DB PCL reconstruction leads to superior biomechanical outcomes and clinical outcomes relative to SB PCL reconstruction. Re-creating native anatomy during PCL reconstruction maximizes biomechanical stability and clinical outcomes.

High return to play rate following treatment of multiple-ligament knee injuries in 136 elite athletes

PURPOSE

The purpose of the study is to assess return to play rate and timing of elite athletes treated for multi-ligament knee injuries with modern surgical techniques.

METHODS

A retrospective review was performed of all professional or national/international level athletes treated for a multi-ligament knee injury by the senior author in the period from February 2001 to October 2019, with a minimum of 2-year follow-up. The study cohort consisted of 136 elite athletes who underwent surgery of two or more knee ligaments. Outcomes measures were return to play (RTP), defined as return to elite level sport, return to play time, and further surgical procedures.

RESULTS

One hundred and twenty (88.2%) athletes returned to elite level sport at an average of 12.8 months from operation. In unicruciate injuries, ACL and PCL-based injuries had similar return to play rates (89.1% vs. 87.5% respectfully, n.s.) although mean RTP time was longer in those with PCL-based injuries (15.2 vs. 11.9 months, p < 0.01). Bicruciate injuries had longer RTP times compared to unicruciate injuries (mean RTP 16.0vs. 12.4 months, p < 0.05) but were able to return at a similar rate (83.3% vs. 88.9%, n.s.). Medial and lateral sided injuries had similar RTP rates (89.3% vs. 87.9%, n.s.) though lateral sided injuries took longer before returning to play (13.4 vs. 11.6 months, p < 0.05). Further surgery was required in 54 (39.9%) patients including 25 (18.4%) manipulations under anaesthesia. Four (2.9%) of the athletes underwent revision ligament surgery.

CONCLUSION

Modern surgical techniques used in the treatment of multi-ligament knee injuries can lead to high return to play rates in elite athletes.

LEVEL OF EVIDENCE

IV.

Biomechanical Assessment of Knee Laxity After a Novel Posterolateral Corner Reconstruction Technique

BACKGROUND

Different techniques to restore knee stability after posterolateral corner (PLC) injury have been described. The original anatomic PLC reconstruction uses 2 separate allografts to reconstruct the PLC. Access to allograft tissue continues to be a significant limitation of this technique, which led to the development of a modified anatomic approach utilizing a single autologous semitendinosus graft fixed on the tibia with an adjustable suspensory loop to enable differential tensioning of the PLC components.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the modified anatomic technique with the original anatomic reconstruction in terms of varus and external rotatory laxity in a cadaveric biomechanical model. The hypothesis was that both techniques would restore varus and external rotatory laxity after a simulated complete PLC injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight pairs of fresh-frozen cadaveric knee specimens were tested to compare the 2 techniques. Varus and external tibial rotation laxity of the knee were measured while applying 10-N·m varus and 5-N·m external rotatory torques at 0°, 30°, 60°, and 90° of flexion. These measurements were tested under 3 conditions: (1) intact fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (2) complete transection of the fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (3) after PLC reconstruction with either the modified (n = 8) or the original (n = 8) technique.

RESULTS

After PLC reconstruction, varus laxity was restored with no statistically significant differences from the intact condition after both reconstruction techniques. Similar outcomes were observed for external rotation in extension; however, in terms of the external rotation limit with respect to the intact joint, significant reductions of mean ± SD 4.1°± 6.3° (P = .036) and 5.1°± 6.6° (P = .016) were recorded with the modified technique at 60° and 90° of flexion, respectively. No significant effect was observed on the neutral flexion kinematics from 0° to 90° of flexion, and no significant differences were observed between reconstructions (P = .222).

CONCLUSION

Both PLC reconstruction techniques restored the normal native varus as compared with the intact knee. Although the modified technique constrained end-range external rotation at 60° and 90° of flexion, no differences were noted with neutral flexion kinematics. Care should be taken when tensioning in the modified technique so that the tibia is in a neutral position to avoid overconstraining the knee.

CLINICAL RELEVANCE

The modified technique may prove useful in situations where there are limited graft options, particularly where allografts are not available or are restricted.

[Anatomical posterolateral complex reconstruction in treating severe posterolateral knee instability using Y-shaped allogeneic Achilles tendon]

OBJECTIVE

To investigate the surgical technique and effectiveness of anatomical posterolateral complex (PLC) reconstruction in treating severe posterolateral knee instability using Y-shaped allogeneic Achilles tendon.

METHODS

The clinical data of 12 patients with Fanelli type C chronic PLC injury with severe posterolateral knee instability who met the selection criteria between June 2013 and August 2017 were retrospectively analyzed. There were 9 males and 3 females, with a median age of 34.5 years (range, 18-57 years). The average time from injury to surgery was 10.5 months (range, 3-24 months). All of them were multi-ligament injuries and were treated with anatomical reconstruction of Y-shaped allogeneic Achilles tendon. The posterior and varus stress X-ray films were used to measure and calculate the difference of posterior displacement of tibia and difference of lateral joint opening distance between bilateral knees to evaluate the backward stability of LCL and knee joint; the knee flexion 30° tibial external rotation test was used to calculate the difference of tibial external rotation angle between bilateral knees to evaluate the stability of knee external rotation. The knee function was evaluated by the International Knee Documentation Committee (IKDC) 2000 subjective and objective scores.

RESULTS

The operation successfully completed in 12 patients, and there was no vascular and nerve injury during operation. The operation time was 2.5-3.5 hours, with an average of 2.7 hours; the intraoperative blood loss was 20-100 mL, with an average of 55 mL. All patients were followed up 13-41 months, with an average of 28.1 months. At last follow-up, the difference of posterior displacement of tibia, the difference of lateral joint opening, the difference of tibial external rotation angle between bilateral knees, and the IKDC2000 subjective score, the objective scores of tibial external rotation and knee varus significantly improved when compared with those before operation ( P<0.05). The knee joint of 1 patient with anterior cruciate ligament, posterior cruciate ligament, and PLC reconstruction was stiff at 15 months after operation, and the range of motion of the knee joint was 10°-80°. After arthroscopic release, the range of motion of the knee joint was 5°-120°, the reconstructed ligament was stable. In the other patients, the knee flexion angle was normal in 2 cases; 9 cases had knee flexion limitation of 5°-10°, with an average of 6.4°; no knee extension was limited.

CONCLUSION

Anatomical PLC reconstruction using Y-shaped allogeneic Achilles tendon can effectively treat Fanelli type C chronic PLC injury with severe posterolateral knee instability and improve the knee joint stability.

The Medial structures of the knee have a significant contribution to posteromedial rotational laxity control in the PCL-deficient knee

PURPOSE

Various reconstruction techniques have been employed to restore normal kinematics to PCL-deficient knees; however, studies show that failure rates are still high. Damage to secondary ligamentous stabilizers of the joint, which commonly occurs concurrently with PCL injuries, may contribute to these failures. The main objective of this study was to quantify the biomechanical contributions of the deep medial collateral ligament (dMCL) and posterior oblique ligament (POL) in stabilizing the PCL-deficient knee, using a joint motion simulator.

METHODS

Eight cadaveric knees underwent biomechanical analysis of posteromedial stability and rotatory laxity using an AMTI VIVO joint motion simulator. Combined posterior force (100 N) and internal torque (5 Nm) loads, followed by pure internal/external torques (± 5 Nm), were applied at 0, 30, 60 and 90° of flexion. The specimens were tested in the intact state, followed by sequential sectioning of the PCL, dMCL, POL and sMCL. The order of sectioning of the dMCL and POL was randomized, providing n = 4 for each cutting sequence. Changes in posteromedial displacements and rotatory laxities were measured, as were the biomechanical contributions of the dMCL, POL and sMCL in resisting these loads in a PCL-deficient knee.

RESULTS

Overall, it was observed that POL transection caused increased posteromedial displacements and internal rotations in extension, whereas dMCL transection had less of an effect in extension and more of an effect in flexion. Although statistically significant differences were identified during most loading scenarios, the increases in posteromedial displacements and rotatory laxity due to transection of the POL or dMCL were usually small. However, when internal torque was applied to the PCL-deficient knee, the combined torque contributions of the dMCL and POL towards resisting rotation was similar to that of the sMCL.

CONCLUSION

The dMCL and POL are both important secondary stabilizers to posteromedial translation in the PCL-deficient knee, with alternating roles depending on flexion angle. Thus, in a PCL-deficient knee, concomitant injuries to either the POL or dMCL should be addressed with the aim of reducing the risk of PCL reconstruction failure.

Thick Graft Versus Double-Bundle Technique on Posterior Cruciate Ligament Reconstruction: Experimental Biomechanical Study with Cadavers

Objective  To evaluate the biomechanical effect of graft thickness compared with the double-bundle technique on posterior cruciate ligament (PCL) reconstruction in human cadaveric knees. Methods  A total of 9 human cadaveric knees were tested in 5 conditions: intact knee (INT); single-bundle reconstruction with a 10-mm quadriceps tendon (SB); double-bundle reconstruction with a 10 mm-quadriceps tendon for the anterolateral bundle and a 7-mm doubled semitendinosus tendon for the posteromedial bundle (DB); single-bundle reconstruction with a 10-mm quadriceps tendon plus a 7-mm doubled semitendinosus tendon (SBT); and PCL-deficient (NoPCL). The posterior tibial translation (PTT) was measured in response to a 134-N posterior tibial load at 0 ^∘ , 30 ^∘ , 60 ^∘ e 90 ^∘ of knee flexion. Results  The PTT values of the DB and SBT techniques were always significantly lower (better stability) than those of the SB technique. The PTT values of the SBT technique were significantly lower than those of the DB technique at 60 ^∘ ( p  = 0.005) and 90 ^∘ ( p  = 0.001). Conclusions  Graft enlargement improves knee stability in isolated PCL reconstructions, whereas the graft division in the two-bundle technique worsens this stability at 60 ^∘ and 90 ^∘ of knee flexion. The findings of the present study suggest that knee stability in PCL reconstructions may be improved with the use of thicker grafts in the SB technique rather than performing the DB technique.

Applied anatomy and three-dimensional visualization of the tendon-bone junctions of the knee joint posterolateral complex

BACKGROUND

To conduct an anatomical study of the fibular collateral ligament (FCL), popliteus tendon (PT), biceps femoris tendon (BT) and popliteofibular ligament (PFL) of the knee joint posterolateral complex (PLC) at the femoral and fibular tendon-bone junctions based on the Chinese Visible Human (CVH) and American Visual Human Project (VHP) datasets and to determine their morphology, contact area, center points and mutual distances with the aim of providing assistance for surgical tunneling scheme.

METHODS

Ten knee joint datasets were selected for segmentation and three-dimensional digital reconstruction. Histological sections images were used to establish criteria for the segmentation. The PLC tendon-junctions were observed and studied.

RESULTS

The FCL and PT had constant attachment to the femur, and the FCL, BT and PFL had constant attachment to the fibula. The tendon-bone junctions of each PLC structure did not have a uniform morphology or the same contact area, but the location of the central point of the tendon-bone junction was similar and regularly attached. All measurements were smaller in the CVH dataset than VHP dataset. At the femoral tendon-bone junction, the average distance between the center points of the FCL and PT was 8.84 ± 1.62 mm (7.73 ± 1.44 mm in the CVH datasets and 9.50 ± 1.38 mm in the VHP datasets).

CONCLUSIONS

The authors propose a surgical tunneling scheme for femoral single-tunnel reconstruction in Chinese PLC reconstruction patients. The research data provide a theoretical basis and guidance for clinicians who need to design and select PLC surgical tunneling schemes.

The role of isolated posterior cruciate ligament reconstruction in knees with combined posterior cruciate ligament and posterolateral complex injury

PURPOSE

This is a meta-analysis comparing biomechanical outcomes to determine whether an isolated posterior cruciate ligament (PCL) reconstruction can restore normal knee kinematics in a combined PCL/posterolateral complex (PLC) injury and whether double-bundle (DB) PCL reconstruction is superior in controlling posterior and rotational laxity compared with single-bundle (SB) PCL reconstruction in a PCL/PLC-deficient knee.

METHODS

A number of electronic databases were searched for relevant articles published through August 2016 that compared biomechanical outcomes of PCL reconstruction in patients who underwent reconstruction for combined PCL/PLC deficiencies. Data were searched, extracted, analysed, and assessed for quality according to Cochrane Collaboration guidelines, and biomechanical outcomes were evaluated using various outcome values. The results are presented as relative ratios for binary outcomes and standard mean differences for continuous outcomes with 95% confidence intervals.

RESULTS

Five biomechanical studies were included in this meta-analysis. There were significant differences in laxities such as posterior tibial translation (PTT), external rotation, varus rotation, and PTT coupled with external rotation in the isolated PCL reconstruction group compared with the native PCL group. Furthermore, there were no significant differences in laxities such as PTT, external rotation, or varus rotation between the SB and DB PCL reconstruction groups.

CONCLUSION

Isolated PCL reconstruction, whether SB or DB, could not restore normal knee kinematics in the PCL/PLC-deficient knee. In such cases, residual laxity after isolated PCL reconstruction can be controlled successfully with PLC reconstruction. Therefore, simultaneous PCL and PLC reconstruction is recommended for patients with combined PCL/PLC injury.

Biomechanical Comparison of Single-Bundle and Double-Bundle Posterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Of the many issues regarding surgical techniques for posterior cruciate ligament (PCL) reconstruction, the choice between single-bundle (SB) and double-bundle (DB) reconstruction is one of the most debated. However, it is unclear which of the reconstruction techniques yields better outcomes in knees with a PCL injury. The purpose of this meta-analysis was to compare the benefits of SB and DB PCL reconstruction in terms of biomechanical outcomes.

METHODS

The MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and SCOPUS electronic databases were searched for relevant articles comparing the outcomes of SB and DB PCL reconstruction that were published up until August 2016. Data searching, extraction, analysis, and quality assessment were performed on the basis of the Cochrane Collaboration guidelines. Biomechanical outcomes of both techniques were evaluated using various outcomes. Results involving continuous outcomes are presented as standardized mean differences (SMDs) with 95% confidence intervals (CIs).

RESULTS

Ten biomechanical studies were included. There were no significant biomechanical differences between the groups with respect to external rotation, varus rotation, or coupled external rotation of the tibia with posterior drawer force at any knee flexion angle. However, posterior laxity measured using the posterior drawer test showed significantly better results after DB compared with SB reconstruction at low flexion (SMD = -0.90, 95% CI = -1.24 to -0.56, I = 0%), 30° (SMD = -0.79, 95% CI = -1.28 to -0.31, I = 48%), 60° (SMD = -0.87, 95% CI = -1.33 to -0.40, I = 33%), and 90° (SMD = -0.73, 95% CI = -1.11 to -0.35, I = 27%).

CONCLUSIONS

Anatomic DB reconstruction of the PCL is superior to anatomic SB reconstruction in terms of restoration of anteroposterior stability. However, it remains unclear which technique yields better improvement in terms of external rotation laxity, varus laxity, and coupled external rotation of the tibia with posterior drawer force. High-quality randomized controlled trials are required to confirm and expand on these results.

Single-Bundle versus Double-Bundle Posterior Cruciate Ligament Reconstruction: A Meta-Analysis of Randomized Controlled Trials

Purpose

This meta-analysis evaluated the benefits of single-bundle (SB) and double-bundle (DB) surgical techniques for posterior cruciate ligament reconstruction (PCLR) in terms of clinical outcomes.

Methods

Five electronic databases were searched for relevant articles published until September 2016. Clinical outcomes of both techniques were evaluated using Lysholm knee function scores, Tegner activity scores, side-to-side differences, and International Knee Documentation Committee (IKDC) objective grades. The results are presented as a risk ratio (RR) for binary outcomes and a weighted mean difference (WMD) for continuous outcomes with a 95% confidence interval (CI).

Results

Four randomized controlled trials (RCTs) were included. There were no significant differences in the Lysholm knee function scores (WMD=1.63; 95% CI, 0.00 to 3.27; I²=0%), Tegner activity scores (WMD=0.17; 95% CI, −0.08 to 0.43; I²=20%), side-to-side differences (WMD=−0.97; 95% CI, −2.41 to 0.47; I²=78%), and IKDC objective grades (RR=1.18; 95% CI, 1.00 to 1.39; I²=0%) at the final follow-up.

Conclusions

The present study demonstrates that both SB and DB techniques for PCLR are comparable in terms of restoration of knee stability and improvement of knee function. However, it is still unclear which technique yields better clinical outcomes. To verify and further corroborate our results, more larger-scale, high-quality RCTs are encouraged.

Arthroscopic Posterior Cruciate Ligament Reconstruction With Remnant Preservation Using a Posterior Trans-septal Portal

We describe a surgical technique for arthroscopic posterior cruciate ligament (PCL) reconstruction with remnant preservation of the original PCL fibers using a posterior trans-septal portal approach. Using the transtibial technique and the posterior trans-septal portal approach allows good visualization of the tibial tunnel preparation, easy access to the tibial tunnel without neurovascular injury, and preservation of remnant PCL fibers. In the preparation of the tibial tunnel, we expose the PCL tibial attachment site completely, detach the posterior capsule from the PCL, and preserve the distal stump of the PCL without neurovascular injury. PCL reconstruction is performed in a way that preserves the remnant PCL fibers. We report on our surgical technique for arthroscopic PCL reconstruction preserving the original PCL fibers.

Management of combined injuries of the posterior cruciate ligament and posterolateral corner of the knee: a systematic review

BACKGROUND

Approximately 60% of posterior cruciate ligament (PCL) injury are associated with a posterolateral corner (PLC) tear.

SOURCES OF DATA

We performed a systematic review of the literature according to the PRISMA guidelines. The following key words were searched on Medline, Cochrane, EMBASE, Google Scholar, and Ovid: 'posterior cruciate ligament' or 'PCL' with 'posterolateral corner' or 'PLC' and 'chronic'; 'injury'; 'management'; 'reconstruction'; 'outcomes'; 'complications'.

AREAS OF AGREEMENT

There was a statistically significant improvement of all clinical scores after surgery regardless of the procedure performed to reconstruct both PCL and PLC.

AREAS OF CONTROVERSY

No randomized control trials were identified on the topic. Standardized methods of functional outcomes assessment are necessary to improve communication on the functional results of the management of PC-PLC.

GROWING POINTS

Single stage surgical reconstruction of PCL and PLC is recommended in patients with posterolateral rotatory instability of the knee.

AREAS TIMELY FOR DEVELOPING RESEARCH

Adequately powered randomized trials with appropriate subjective and objective outcome measures are necessary to reach definitive conclusions.

Tibial Slope Strongly Influences Knee Stability After Posterior Cruciate Ligament Reconstruction: A Prospective 5- to 15-Year Follow-up

BACKGROUND

The reported failure rate after posterior cruciate ligament (PCL) reconstruction remains high. Previous studies have shown that the tibial slope (TS) influences sagittal plane laxity. Consequently, alterations of TS might have an effect on postoperative knee stability after PCL reconstruction.

HYPOTHESIS

We hypothesized that flattening of TS is associated with increased posterior laxity after PCL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence 3.

METHODS

This study consisted of 48 patients who underwent PCL reconstruction in a single-surgeon series. Eight patients underwent an isolated PCL reconstruction, 27 patients underwent an additional posterolateral corner reconstruction, and 13 patients underwent a combined reconstruction of the PCL, anterior cruciate ligament, and posterolateral corner. Three blinded observers measured TS and the side-to-side difference (SSD) of posterior tibial translation (PTT) before and after PCL reconstruction using standardized stress radiographs. The minimum follow-up was 5 years.

RESULTS

At a mean follow-up of 103 months (range, 65-187), the mean SSD of PTT was significantly reduced (10.9 ± 2.9 vs 4.9 ± 4.3 mm; P < .0001). The mean TS was 8.0° ± 3.7° (range, 1°-14.3°) for the operated knee and 7.9° ± 3.2° (range, 2°-15.3°) for the contralateral knee. There was a statistically significant correlation between TS and PTT ( r = -0.77 and R² = 0.59; P < .0001). In addition, there was a significant correlation between TS and the postoperative reduction of PTT ( r = 0.74 and R² = 0.55; P < .0001). Subgrouping according to the number of operated ligaments showed no significant differences regarding TS or the mean reduction of PTT.

CONCLUSION

Flattening of TS is associated with a significantly higher remaining PTT as well as a lower reduction of PTT. Notably, these results are irrespective of sex and number of ligaments addressed. Thus, isolated soft tissue procedures in PCL deficiency may only incompletely address posterior knee instability in patients with flattening of the posterior slope.

Biomechanical comparison of two surgical techniques for press-fit reconstruction of the posterolateral complex of the knee

BACKGROUND

To date, various surgical techniques to treat posterolateral knee instability have been described. Recent studies recommended an anatomical and isometric reconstruction of the posterolateral corner addressing the key structures, such as lateral collateral ligament (LCL), popliteus tendon (POP) and popliteofibular ligament (PFL). Two clinical established autologous respective local reconstruction methods of the posterolateral complex were tested for knot-bone cylinder press-fit fixation to assess efficacy of each reconstruction technique in comparison to the intact knee.

NULL HYPOTHESIS

The knot-bone cylinder press-fit fixation for both anatomic and isometric reconstruction techniques of the posterolateral complex shows equal biomechanical stability as the intact posterolateral knee structures.

STUDY DESIGN

This was a controlled laboratory study.

METHODS

Two surgical techniques (Larson: fibula-based semitendinosus autograft for LCL and PFL reconstruction/Kawano: biceps femoris and iliotibial tract autograft for LCL, PFL and POP reconstruction) with press-fit fixation were used for restoration of posterolateral knee stability. Seven cadaveric knees (66 ± 3.4 years) were tested under three conditions: intact knee, sectioned state and reconstructed knee for each surgical technique. Biomechanical stress tests were performed for every state at 30° and 90° knee flexion for anterior-posterior translation (60 N), internal-external and varus-valgus rotation (5 Nm) at 0°, 30° and 90° using a kinemator (Kuka robot).

RESULTS

At 30° and 90° knee flexion, no significant differences between the four knee states were registered for anterior-posterior translation loading. Internal-external and varus-valgus rotational loading showed significantly higher instability for the sectioned state than for the intact or reconstructed posterolateral structures (p < 0.05). There were no significant differences between the intact and reconstructed knee states for internal-external rotation, varus-valgus rotation and anterior-posterior translation at any flexion angles (p > 0.05). Comparing both reconstruction techniques, significant higher varus-/valgus stability was registered for the fibula-based Larson technique at 90° knee flexion (p < 0.05).

CONCLUSIONS

Both PLC reconstructions showed equal biomechanical stability as the intact posterolateral knee structures when using knot-bone cylinder press-fit fixation. We registered restoration of the rotational and varus-valgus stability with both surgical techniques. The anterior-posterior translational stability was not influenced significantly. The Larson technique showed significant higher varus/valgus stability in 90° flexion. The latter is easier to perform and takes half the preparation time, but needs grafting of the semitendinosus tendon. The Kawano reconstruction technique is an interesting alternative in cases of missing autografts.

Surgical treatment of posterior cruciate ligament insufficiency in the United States

The purpose of this study was to investigate the latest trends and demographics of surgical treatment of posterior cruciate ligament (PCL) insufficiency in the United States. Patients who underwent surgical treatment of PCL insufficiency from 2007 to 2011 were identified by searching the International Classification of Diseases, Ninth Revision, Clinical Modification codes and Current Procedural Terminology codes in the PearlDiver Patient Records Database (PearlDiver Technologies, Warsaw, Indiana), a publicly available national database of insurance records. The chronicity of injury, year of procedure, age, sex, region of the United States the surgery was performed, and other concomitant meniscus and ligamentous operations were elicited for each patient. In total, 701 cases of surgical PCL procedures (222 isolated and 479 combined) were identified. More PCL surgeries were completed for acute injuries (74%) than for chronic injuries (26%). Among associated procedures, meniscectomies and meniscus repairs were performed for 293 (41%) and 51 (7%) patients, respectively. Meniscectomies were completed in 77 (35%) isolated reconstructions vs 216 (45%) combined reconstructions (P=.01; odds ratio, 0.65). Of the combined PCL surgeries, anterior cruciate ligament (ACL)/PCL was the most common (62%), followed by ACL/PCL/collateral ligament repair (11%) and PCL/other ligamentous reconstruction (9%). No specific trends were observed in the yearly number of PCL procedures performed. The peak number of isolated PCL surgeries was observed in a younger age group (20-29 years) than that of combined PCL surgeries (30-39 years) (P<.01). Surgical treatment for PCL insufficiency remains reserved for acute multiligamentous knee injuries, with ACL/PCL operations being the most common combined procedure.

Biomechanical analysis of posterior cruciate ligament reconstruction with aperture femoral fixation

The goal of this study was to determine whether single-tunnel-double-bundle-equivalent posterior cruciate ligament (PCL) reconstruction using an aperture femoral fixation device better replicated normal knee kinematics than single-bundle reconstruction. Eight fresh-frozen human cadaver knees underwent arthroscopically assisted PCL reconstruction and were examined with a robotic testing system to assess knee joint kinematics under combinations of applied internal, neutral, and external rotational tibial torque and anteroposterior translational forces at 0°, 30°, 60°, 90°, and 120° flexion. Three conditions were tested: (1) intact PCL; (2) single-tunnel PCL reconstruction with anterolateral and posteromedial bundle fixation at 90°/90° (single bundle); and (3) 90°/0° (double-bundle equivalent), respectively. Posterior tibial translation was the primary outcome measure. Compared with the intact knee, double-bundle-equivalent reconstruction under external tibial torque allowed greater posterior translation across the flexion arc as a whole (P=.025) and at 30° flexion (P=.027) when results were stratified by flexion angle. No other kinematic differences were found with single-bundle or double-bundle-equivalent fixation, including mediolateral translation and both coupled and isolated tibial rotation (P>.05). Single-bundle PCL reconstruction closely approximated native knee rotational and translational kinematics, whereas double-bundle-equivalent reconstruction permitted increased posterior translation with applied external tibial torque, particularly at lower flexion angles. Single-bundle PCL reconstruction provides knee stability similar to the intact condition, making it a practical alternative to conventional double-bundle PCL reconstruction. The authors found that double-bundle-equivalent reconstruction provided no advantage to justify its clinical use.

The predictive effect of anatomic femoral and tibial graft tunnel placement in posterior cruciate ligament reconstruction on functional and radiological outcome

PURPOSE

Biomechanical reports have advocated anatomic graft tunnel placement for reconstruction of the posterior cruciate ligament (PCL) to restore knee joint stability and facilitate optimal functional outcome. However, in vivo investigations that correlate tunnel position to functional results are lacking so far. This study evaluates the anatomic accuracy of femoral and tibial tunnel apertures on postoperative computed tomography (CT) scans and compares these findings to subjective and objective clinical outcome parameters.

METHODS

After single-bundle PCL reconstruction, 29 patients were stratified into several subgroups according to the anatomic accuracy of femoral and tibial tunnel apertures measured on postoperative CT scans. A threshold value for the centres of the tunnel apertures was determined using a measurement grid system as a radiographic reference. To evaluate the functional and radiological results, visual analogue scale, International Knee Documentation Committee (IKDC), Tegner, Lysholm, Knee Injury and Osteoarthritis Outcome Score and osteoarthritis scores were obtained.

RESULTS

Comparison between functional outcome and tunnel position yielded a statistically significant difference for subjective IKDC score and angle segment α and for objective stability and tunnel position P3 but no statistically significant difference with respect to intercondylar depth, intercondylar height and tibial tunnel position P2. No correlation was found between anatomic tunnel position and present or progressive osteoarthritis on follow-up. Of the patients, 72 % classified their result as excellent and good and 90 % would repeat surgical treatment.

CONCLUSIONS

Despite a small sample size and subject to the threshold values we used, our data indicate a potentially minor effect of anatomic tunnel placement on midterm functional outcome following PCL reconstruction.

Clinical, Functional, and Morphological Evaluations of Posterior Cruciate Ligament Reconstruction With Remnant Preservation: Minimum 2-Year Follow-up

BACKGROUND

Numerous posterior cruciate ligament (PCL) reconstruction techniques have evolved and have revealed satisfactory outcomes; however, the optimal operative method for PCL reconstruction remains controversial.

HYPOTHESIS

Transtibial PCL reconstruction with a remnant preservation technique would result in successful clinical, radiological, functional, and morphological outcomes. In addition, it was hypothesized that the results of combined PCL and posterolateral corner (PLC) reconstruction would be comparable with those of isolated PCL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 168 patients who underwent arthroscopic PCL reconstruction with or without reconstruction of the PLC between March 2006 and June 2011 were retrospectively reviewed. Ninety-two patients who met the inclusion criteria were enrolled, and 47 of 92 patients who underwent combined PCL and PLC reconstruction were evaluated as a subgroup. The PLC was reconstructed using the single fibular sling method. The patients were assessed by means of the Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score, and Tegner activity score. Stability was evaluated using a KT-2000 arthrometer and Telos device. Proprioception was assessed using the Biodex System. Follow-up magnetic resonance imaging (MRI) was performed in 34 patients, and second-look arthroscopic surgery was conducted in 36 patients.

RESULTS

The minimum follow-up duration was 24 months in all patients. Clinical outcomes and posterior instability improved significantly. The mean Lysholm score improved from 56.7 ± 7.1 to 89.3 ± 7.3, the mean IKDC subjective knee score improved from 53.3 ± 9.6 to 86.2 ± 6.1, and the mean Tegner activity score was 2.5 ± 0.8 preoperatively and 5.1 ± 1.3 postoperatively (all P < .001). The mean side-to-side difference on posterior stress radiography with the Telos device improved significantly, decreasing from 12.1 ± 2.5 mm to 2.7 ± 1.3 mm (P < .001). The mean side-to-side difference on varus stress radiography was reduced from 5.9 ± 0.8 mm preoperatively to 1.3 ± 1.0 mm after combined PCL and PLC reconstruction (P < .001). Postoperative proprioception recovered to a level similar to that of the uninvolved side, and MRI and second-look arthroscopic surgery showed a high rate of complete healing and synovialization in patients who underwent either isolated PCL reconstruction or combined PLC and PCL reconstruction.

CONCLUSION

Transtibial PCL reconstruction with remnant preservation resulted in satisfactory clinical, functional, radiological, and morphological outcomes. The results of combined posterolateral rotatory instability were comparable with those for isolated PCL reconstruction with adequate PLC reconstruction.

Posterior cruciate ligament: focus on conflicting issues

There is little consensus on how to optimally reconstruct the posterior cruciate ligament (PCL) and the natural history of injured PCL is also unclear. The graft material (autograft vs. allograft), the type of tibial fixation (tibial inlay vs. transtibial tunnel), the femoral tunnel position within the femoral footprint (isometric, central, or eccentric), and the number of bundles in the reconstruction (1 bundle vs. 2 bundles) are among the many decisions that a surgeon must make in a PCL reconstruction. In addition, there is a paucity of information on rehabilitation after reconstruction of the PCL and posterolateral structures. This article focused on the conflicting issues regarding the PCL, and the scientific rationales behind some critical points are discussed.

Combined PCL and PLC reconstruction in chronic posterolateral instability

PURPOSE

The posterolateral corner (PLC) is more likely to be injured in combination with the posterior cruciate ligament (PCL) or the anterior cruciate ligament than in isolation. This leads to instability of the knee and loss of function. We hypothesised that combined PCL and PLC reconstruction would restore sufficient stability to allow improvement in patient symptoms and function.

METHODS

19 patients who underwent arthroscopic-assisted single-bundle PCL and PLC reconstruction by a single surgeon were analysed retrospectively. The PLC reconstruction was a modified Larson reconstruction of the lateral collateral ligament and the popliteofibular ligament. The IKDC and Tegner scores were used to assess outcome. Dial test and varus laxity were used to assess improvements in clinical laxity. Posterior laxity was tested using the KT-1000.

RESULTS

The mean follow-up was 38 months (±(2× standard deviations), ±12.3). There were no postoperative complications. All patients had less than 5 mm posterior step-off. 17 of 19 patients had negative dial and varus stress tests. Measured range of motion was reduced by a mean of 10°, but patients did not report any daily activities restrictions. Tegner scores improved from a median pre-operative value of 2 (range 1-4) to 6 (4-9) at final follow-up. The mean postoperative IKDC score was 86 (±11).

CONCLUSIONS

Subjectively, the knee stability achieved allowed daily activities. However, there were remaining abnormalities in range of motion, posterior drawer and rotational laxity, suggesting that normal knee laxity was not restored.

LEVEL OF EVIDENCE

IV.

Biomechanical techniques to evaluate tibial rotation. A systematic review

PURPOSE

This article systematically reviewed the biomechanical techniques to quantify tibial rotation, for an overview of how to choose a suitable technique for specific clinical application.

METHODS

A systematic search was conducted and finally 110 articles were included in this study. The articles were categorized by the conditions of how the knee was examined: external load application, physical examination and dynamic task.

RESULTS

The results showed that two-thirds of the included studies measured tibial rotation under external load application, of which over 80% of the experiments employed a cadaveric model. The common techniques used included direct displacement measurement, motion sensor, optical tracking system and universal force moment sensor. Intra-operative navigation system was used to document tibial rotation when the knee was examined by clinical tests. For dynamic assessment of knee rotational stability, motion analysis with skin reflective markers was frequently used although this technique is less accurate due to the skin movement when compared with radiographic measurement.

CONCLUSION

This study reports various biomechanical measurement techniques to quantify tibial rotation in the literatures. To choose a suitable measurement technique for a specific clinical application, it is suggested to quantify the effectiveness of a new designed surgical technique by using a cadaveric model before applying to living human subjects for intra-operative evaluation or long-time functional stability assessment. Attention should also be paid on the study's purpose, whether to employ a cadaveric model and the way of stress applied to the knee.

LEVEL OF EVIDENCE

IV.

The effect of proximal tibial slope on dynamic stability testing of the posterior cruciate ligament- and posterolateral corner-deficient knee

BACKGROUND

Proximal tibial slope has been shown to influence anteroposterior translation and tibial resting point in the posterior cruciate ligament (PCL)-deficient knee. The effect of proximal tibial slope on rotational stability of the knee is unknown.

HYPOTHESIS

Change in proximal tibial slope produced via osteotomy can influence both static translation and dynamic rotational kinematics in the PCL/posterolateral corner (PLC)-deficient knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Posterior drawer, dial, and mechanized reverse pivot-shift (RPS) tests were performed on hip-to-toe specimens and translation of the lateral and medial compartments measured utilizing navigation (n = 10). The PCL and structures of the PLC were then sectioned. Stability testing was repeated, and compartmental translation was recorded. A proximal tibial osteotomy in the sagittal plane was then performed achieving either +5° or -5° of tibial slope variation, after which stability testing was repeated (n = 10). Analysis was performed using 1-way analysis of variance (ANOVA; α = .05).

RESULTS

Combined sectioning of the PCL and PLC structures resulted in a 10.5-mm increase in the posterior drawer, 15.5-mm increase in the dial test at 30°, 14.5-mm increase in the dial test at 90°, and 17.9-mm increase in the RPS (vs intact; P < .05). Increasing the posterior slope (high tibial osteotomy [HTO] +5°) in the PCL/PLC-deficient knee reduced medial compartment translation by 3.3 mm during posterior drawer (vs deficient; P < .05) but had no significant effect on the dial test at 30°, dial test at 90°, or RPS. Conversely, reversing the slope (HTO -5°) caused a 4.8-mm increase in medial compartment translation (vs deficient state; P < .05) during posterior drawer and an 8.6-mm increase in lateral compartment translation and 9.0-mm increase in medial compartment translation during RPS (vs deficient state; P < .05).

CONCLUSION

Increasing posterior tibial slope diminished static posterior instability of the PCL/PLC-deficient knee as measured by the posterior drawer test but had little effect on rotational or dynamic multiplanar stability as assessed by the dial and RPS tests, respectively. Conversely, decreasing posterior slope resulted in increased posterior instability and a significant increase in the magnitude of the RPS.

CLINICAL RELEVANCE

These results suggest that increasing posterior tibial slope may improve sagittal stability in the PCL/PLC-deficient knee. Moreover, a knee with diminished posterior tibial slope may demonstrate greater multiplanar instability in this setting. Consequently, proximal tibial slope should be considered when treating combined PCL/PLC injuries of the knee.

Evaluation and management of posterior cruciate ligament injuries

BACKGROUND

Posterior cruciate ligament injuries are increasingly recognized, the result of various sports activities, and while most athletes return to sports the development degenerative joint changes is common.

OBJECTIVE

To provide a synopsis of the current best evidence regarding the recognition and treatment of posterior cruciate ligament injuries.

DESIGN

Structured narrative review.

METHODS

Keyword search of Medline, CINAHL, and PEDro databases for studies published in English from January 1975 to July 2011. Additionally, the reference lists from articles obtained were manually searched for relevant literature.

SUMMARY

The manuscript provides an overview of posterior cruciate ligament injury, discusses diagnostic methods to include radiographic examination techniques, and presents information on surgical and conservative management of PCL injuries.

CONCLUSION

Understanding the mechanism of injuries and most effective examination methods can aide in effective early recognition of PCL injuries. Appropriate management of the patient with PCL deficiency or reconstructed knee will optimize outcomes and potentially affect long term knee function.

Anatomical Reconstruction for Chronic Posterolateral Instability Combined with Posterior Cruciate Ligament Reconstruction: Surgical Technique

Introduction

We present surgical techniques for the anatomical reconstruction of the popliteus tendon and the lateral collateral ligament (LCL) with use of a tibialis posterior allograft for posterolateral corner insufficiency combined with anterolateral transtibial single-bundle posterior cruciate ligament (PCL) reconstruction with use of an Achilles tendon-bone allograft with a one-incision technique.

Step 1 Create the Portals

Use a parapatellar high anteromedial portal, a far anterolateral portal, and a high posteromedial portal.

Step 2 Prepare the Tibial Tunnel and Femoral Socket for the PCL Reconstruction

To reduce the graft/socket divergence, (1) flex the knee >100°, (2) push the proximal part of the tibia backward as much as possible, and (3) introduce the cannulated headed reamer through the far anterolateral portal with a smooth plastic sheath and push up posteriorly to make contact with the lateral femoral condyle.

Step 3 Prepare Pass and Fix the Graft for the PCL Reconstruction

Tie a 9-mm EndoPearl device securely to the tip of the tendon to improve the fixation strength.

Step 4 Make the Skin Incision and Develop the Surgical Plane for the Posterolateral Corner Reconstruction

Create a 7-mm fibular tunnel in a counterclockwise direction to avoid breaking the lateral cortex of the fibular tunnel or injuring the peroneal nerve.

Step 5 Prepare Pass and Fix the Graft for the Posterolateral Corner Reconstruction

Change the patient's position to a lateral or semi-lateral decubitus position to prevent an inappropriate posterolateral corner reconstruction by the posterolateral corner of the knee sagging in the supine position due to gravity.

Step 6 Postoperative Rehabilitation

Immobilize the knee in extension, with the proximal part of the tibia supported with cotton pads to prevent posterior drooping, which may lead to graft stretch or failure.

Results

We performed a two-year follow-up study comparing the procedures described here (Group A) with the same PCL reconstruction technique combined with a modified biceps rerouting tenodesis to address the posterolateral corner deficiency (Group B).

What to Watch For

IndicationsContraindicationsPitfalls & Challenges.

Revision posterior cruciate ligament reconstruction using a modified tibial-inlay double-bundle technique

BACKGROUND

Revision of an unsuccessful posterior cruciate ligament (PCL) reconstruction is a complicated clinical procedure with an outcome that may be less satisfactory than that after a typical primary PCL reconstruction. The purpose of this study was to evaluate the reasons for failure of primary PCL reconstructions and to determine the clinical outcomes of revision PCL reconstruction after a minimum of two years of follow-up.

METHODS

Twenty-eight revision PCL reconstructions were performed by a single surgeon. Four cases that involved diverse operative procedures and two cases with a duration of follow-up of less than twenty-four months were excluded; the outcomes of the remaining twenty-two reconstructions were analyzed at the time of the latest follow-up (at least twenty-four months postoperatively). A technique involving a double femoral tunnel, a modified tibial inlay, and Achilles tendon allograft was used in all twenty-two of these revision reconstructions. Seventeen patients (77%) underwent concomitant reconstruction of posterolateral corner structures. Knee stability was measured with use of posterior stress radiography as well as with a maximum manual displacement test utilizing a KT1000 arthrometer. The subjective International Knee Documentation Committee (IKDC) and objective Orthopädische Arbeitsgruppe Knie (OAK) scoring systems were used to evaluate the clinical outcome.

RESULTS

Nine (41%) of the primary PCL reconstructions most likely failed because of a single factor and thirteen (59%) most likely failed because of multiple factors. The most common probable causes of failure were posterolateral rotatory instability (seventeen knees, 77%) and improper graft tunnel placement (nine knees, 41%). Side-to-side differences during posterior stress radiography improved from 9.9 ± 2.8 mm preoperatively to 2.8 ± 1.8 mm at the time of the latest follow-up (p < 0.001). The subjective and objective clinical scores at the latest follow-up evaluation were significantly better than the preoperative scores (p < 0.001).

CONCLUSIONS

Arthroscopic revision PCL reconstruction with use of the modified tibial-inlay double-bundle technique improved knee stability, as measured with posterior stress radiography and clinically, and outcomes. Associated posterolateral rotatory instability should be surgically corrected during PCL reconstruction to prevent graft failure resulting from abnormal opening of the lateral aspect of the tibiofemoral joint.

Surgical technique: aperture fixation in PCL reconstruction: applying biomechanics to surgery

BACKGROUND

Biomechanical studies suggest reducing the effective graft length during transtibial posterior cruciate ligament (PCL) reconstruction by augmenting the distal tibial fixation with a proximal screw near the tibial tunnel aperture could increase graft stiffness and provide a more stable reconstruction. However, it remains unknown to what extent this mechanical theory influences in vivo graft performance over time.

SURGICAL TECHNIQUE

We developed a technique to augment tibial distal fixation with a proximal screw near the tibial tunnel aperture to shorten the effective graft length and increase graft stiffness.

PATIENTS AND METHODS

We retrospectively reviewed all 10 patients who had isolated PCL reconstructions with combined distal and proximal tibial fixation from 2003 to 2007. Mean age of the patients was 36.5 years. We measured ROM and obtained Tegner, International Knee Documentation Committee (IKDC), and Lysholm scores. Anteroposterior stability was evaluated with a KT-2000 arthrometer. Minimum followup was 1 year (mean, 2.5 years; range, 1-4.8 years).

RESULTS

Mean Tegner scores before injury and at last followup were 7.3 and 6.5, respectively. Mean postoperative IKDC score was 87 versus a preoperative IKDC score of 43. Mean Lysholm score was 89 at last followup. All patients achieved full terminal extension. No patient had greater than a 5-mm difference in anterior or posterior displacement from the contralateral knee as measured by a KT-2000 arthrometer postoperatively (0.93 ± 0.79 mm).

CONCLUSIONS

In this small series, augmentation of tibial distal fixation with a proximal screw near the tibial tunnel aperture during reconstruction of the isolated PCL rupture restored function, motion, and stability.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Posterior cruciate ligament and posterolateral corner deficiency results in a reverse pivot shift

BACKGROUND

As measured via static stability tests, the PCL is the dominant restraint to posterior tibial translation while the posterolateral corner is the dominant restraint to external tibial rotation. However, these uniplanar static tests may not predict multiplanar instability. The reverse pivot shift is a dynamic examination maneuver that may identify complex knee instability.

QUESTIONS/PURPOSES

In this cadaver study, we asked whether (1) isolated sectioning or (2) combined sectioning of the PCL and posterolateral corner increased the magnitude of the reverse pivot shift and (3) the magnitude of the reverse pivot shift correlated with static external rotation or posterior drawer testing.

METHODS

In Group I, we sectioned the PCL followed by structures of the posterolateral corner. In Group II, we sectioned the posterolateral corner structures before sectioning the PCL. We performed posterior drawer, external rotation tests, and mechanized reverse pivot shift for each specimen under each condition and measured translations via navigation.

RESULTS

Isolated sectioning of the PCL or posterolateral corner had no effect on the reverse pivot shift. Conversely, combined sectioning of the PCL and posterolateral corner structures increased the magnitude of the reverse pivot shift. The magnitude of the reverse pivot shift correlated with the posterior drawer and external rotation tests.

CONCLUSIONS

Combined sectioning of the PCL and posterolateral corner was required to cause an increase in the magnitude of the mechanized reverse pivot shift. The reverse pivot shift correlated with both static measures of stability.

CLINICAL RELEVANCE

Combined injury to the PCL and posterolateral corner should be considered in the presence of a positive reverse pivot shift.

Biomechanical evaluation of an anatomic double-bundle posterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to evaluate the effect of the anatomic double-bundle reconstruction (ADBR) of the posterior cruciate ligament (PCL) with 2 femoral tunnels and 2 tibial tunnels.

METHODS

Eight fresh-frozen human knees were used. Bone tunnels were created based on the PCL anatomic footprints. A 9-mm looped semitendinosus and gracilis tendon for anterolateral bundle reconstruction (ALR), a 7-mm looped semitendinosus tendon for posteromedial bundle reconstruction (PMR), and the same grafts for the ADBR were used. Under a 100-N posterior tibial load and under a 100-N posterior tibial load and 5 Nm of external tibial torque, the posterior tibial translation (PTT) was measured.

RESULTS

Under posterior tibial load, at 0°, the PTT of the ALR was larger than that of the intact knee (P = .04) and the ADBR (P = .03); however, there were no significant differences between the PTT of the PMR and that of the ADBR (P = .28) and intact knee (P = .99). At 30°, the PTT of the ADBR was smaller than that of the ALR (P = .02) and PMR (P = .02). At 60°, the PTT of the PMR was larger than that of the ADBR (P = .02). At 90°, the PTT of the PMR was larger than that of the ADBR (P = .02). Under posterior tibial load and external tibial torque, at 0°, the PTT of the ALR was larger than that of the ADBR (P = .04).

CONCLUSIONS

Although the graft size of the ADBR was larger than other reconstructions, the ADBR was better than the ALR at 0° and 30° of knee flexion under the posterior tibial load and at 0° under the combination of posterior tibial load and external tibial torque, as well as better than the PMR at 30°, 60°, and 90° of knee flexion under the posterior tibial load.

CLINICAL RELEVANCE

The clinical outcome of PCL reconstruction might improve by reducing posterior knee laxity in knee extension with the ADBR.

Posterior cruciate ligament: anatomy, biomechanics, and outcomes

The optimal treatment of posterior cruciate ligament ruptures remains controversial despite numerous recent basic science advances on the topic. The current literature on the anatomy, biomechanics, and clinical outcomes of posterior cruciate ligament reconstruction is reviewed. Recent studies have quantified the anatomic location and biomechanical contribution of each of the 2 posterior cruciate ligament bundles on tunnel placement and knee kinematics during reconstruction. Additional laboratory and cadaveric studies have suggested double-bundle reconstructions of the posterior cruciate ligament may better restore normal knee kinematics than single-bundle reconstructions although clinical outcomes have not revealed such a difference. Tibial inlay posterior cruciate ligament reconstructions (either open or arthroscopic) are preferred by many authors to avoid the "killer turn" and graft laxity with cyclic loading. Posterior cruciate ligament reconstruction improves subjective patient outcomes and return to sport although stability and knee kinematics may not return to normal.

Measurement of rotational laxity of the knee: in vitro comparison of accuracy between the tibia, overlying skin, and foot

BACKGROUND

Posterolateral corner (PLC) injuries are difficult to diagnose and cause significant morbidity. The ideal method for the dial test and its accuracy remain unclear.

PURPOSE

This study compares the accuracy of measuring tibial external rotation at the skeletal level to measuring the patella-tubercle angle (PTA) and the thigh-foot angle (TFA) in the supine position to assess the most accurate method to measure rotation during the dial test.

STUDY DESIGN

Controlled laboratory study.

METHODS

Measurements were compared simultaneously using rotational goniometers at a cutaneous splint over the tibia, at a foot splint, and directly from the tibial skeleton. Six lower limbs were used. The femur was held rigidly and the knee tested at 90° and 30° of flexion. External rotation torque up to 8 N·m was applied through the foot splint, and the rotations were measured by 2 testers.

RESULTS

Measurements at the tibial splint and directly on the tibia showed significant correlation at both knee flexion angles. The mean tibial external rotation was 24° at 90° of flexion and 26° at 30° of flexion (P < .05). The soft tissue effect caused the tibial splint to overestimate rotations by a mean of 6° and 9° at 90° and 30° of flexion, respectively. Foot splint measurements did not correlate significantly with tibial rotation, overestimating rotations by a mean of 103%. Intratester and intertester intraclass correlations were significant for the skin-mounted tibial splint measurements at both flexion angles but not for foot splint measurements at either flexion angles.

CONCLUSION

Rotation of the foot did not accurately represent the tibial external rotation at the knee, which could be measured more accurately by an instrument resting on the skin via a molded tibial splint. These results suggest that the PTA, and not the TFA, should be used in the dial test. This would support the use of the supine position during the dial test.

CLINICAL RELEVANCE

The dial test is a commonly used method for diagnosing PLC injuries. This study helps to identify the ideal position and measuring points to use for this test; measurements based on the tibia were more accurate than those that used rotation of the foot.

Computed tomography evaluation of the femoral and tibial attachments of the posterior cruciate ligament in vitro

PURPOSE

The optimal technique for reconstruction of the posterior cruciate ligament (PCL) is controversial. Regardless of surgical technique and graft choice, anatomic graft placement is essential for successful outcome. The purpose of this study is to evaluate the size and location of the insertions of the PCL using a computed tomography (CT) protocol.

METHODS

The insertions in ten knees were marked in vitro with plastic markers. The CT examination was performed with the knee in extension. On the femur, the position of the center of the insertion site was evaluated relative to Blumensaat's line and the anterior articular surface. On the tibia, the location of the center of the insertion site was described relative to the borders of the tibial plateau and the retrospinal surface.

RESULTS

The surface area of the femoral insertion measured 232 mm(-2) and was centered 8.9 mm from the roof of the intercondylar notch and 18.7 mm from the anterior articular cartilage surface. The surface area of the tibial insertion was 155 mm(2) and was centered 9.1 mm from the posterior border of the tibia on the retrospinal surface, 1.6 mm inferior to the plane of the tibial articular surface. This point was on average 49% of the way across the plateau relative to the medial edge of the plateau and 87% of the way across the plateau relative to the anterior edge.

CONCLUSIONS

Computed tomography can provide detailed localization of the PCL attachment sites on the femur and tibia. Radiation exposure and cost may preclude routine use.

Biomechanical comparisons between 4-strand and modified Larson 2-strand procedures for reconstruction of the posterolateral corner of the knee

BACKGROUND

The posterolateral corner (PLC) resists tibial varus angulation, external rotation, and, to a lesser extent, posterior translation. It is important that reconstructions of posterolateral knee injuries restore joint laxity and patient function, but residual laxities are often observed.

HYPOTHESIS

The knee laxity after a new 4-strand PLC reconstruction would be closer to normal than after a 2-strand "modified Larson" reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fourteen intact cadaveric knees were mounted in a 6 degrees of freedom rig and subjected to the following external loading conditions: a 90-N posterior tibial force, a 5-N·m external rotation torque, and 5-N·m varus moment. Knee kinematics were recorded with an active optical tracking system for the intact, PLC-deficient, modified Larson PLC reconstruction and 4-strand PLC reconstruction.

RESULTS

With external tibial torque, the rotational laxity in 4-strand reconstruction was significantly less than in the PLC-deficient (P < .0001) and modified Larson reconstruction (P = .0112) and did not differ significantly from intact laxity at any angle of flexion. In response to posterior load, posterior translation did not change in any of the tested conditions, while the coupled external rotation laxity in 4-strand PLC reconstruction was significantly less than in the PLC-deficient (P < .0001) and modified Larson reconstruction (P < .0486) and was not significantly different from the intact movements for both reconstructions. The varus angulation-versus-flexion curves were significantly different between the PLC-deficient and both PLC reconstructions (P < .0001). The varus laxity was not significantly different between the modified Larson reconstruction, the 4-strand reconstruction, and the intact knee.

CONCLUSION

This study showed that the rotational knee laxity in response to both external rotation and posterior translation load were significantly better after the 4-strand PLC reconstruction than after the modified Larson reconstruction, although significant differences were not found between the 2 procedures for varus laxity.

CLINICAL RELEVANCE

The 4-strand PLC reconstruction may produce a better biomechanical outcome, especially during external rotation and posterior translation tibial load. The authors suggest that this relates to load sharing among 4 graft strands crossing the joint.

All-arthroscopic repair of arcuate avulsion fracture with suture anchor

Arcuate avulsion fractures are very rare but present pathologic posterolateral rotation instability. Untreated instability may lead to overload of the reconstructed posterior cruciate ligament (PCL) graft. Surgical treatment and clinical results have not yet been reported to our knowledge. This study presents the case of a 45-year-old man with PCL injury and an arcuate avulsion fracture of the fibular head. The dial test was positive preoperatively, and magnetic resonance imaging showed an "arcuate" sign. The avulsed bone fragment was reduced and fixed with a suture anchor by an all-arthroscopic technique. At the 1-year follow-up, the patient had resumed all his normal activities, including sports. He scored 1+ on the posterior drawer test, and external rotation was 1° less than that in his contralateral normal knee. Compared with the values in the contralateral normal knee, the posterior tibial translation was reduced from 15.5 mm preoperatively to 6.3 mm postoperatively. The postoperative magnetic resonance imaging and computed tomography scans showed that the reconstructed PCL graft and the osseous fragment of the styloid process of the fibular head attached to the popliteofibular ligament were reduced. This technical note describes an all-arthroscopic reduction and fixation technique of arcuate avulsed fracture of the fibular head.

Combined posterolateral corner reconstruction with remnant tensioning and augmentation in chronic posterior cruciate ligament injuries: minimum 2-year follow-up

PURPOSE

To evaluate functional results and knee stability after tensioning of remnant posterior cruciate ligament (PCL) with anterolateral (AL) bundle reconstruction and posterolateral corner (PLC) reconstruction in chronic PCL and PLC injuries.

METHODS

Between March 2001 and March 2007, 95 patients with chronic PCL injuries combined with PLC injuries underwent tensioning of the remnant PCL with AL bundle reconstruction and PLC reconstruction. Among these 95 patients, 70 who were satisfied with our inclusion were reviewed. The mean follow-up period was 40.1 months (range, 24 to 96 months). Tensioning of remnant PCL fibers was performed by distal transfer of the posterior tibial attachment. The AL bundle of the PCL was reconstructed by use of the modified inlay technique. The PLC reconstructive procedure was performed with a single sling through fibular tunnel. Stability was measured on posterior stress radiographs and by use of a maximal manual displacement test performed with a KT-1000 arthrometer (MEDmetric, San Diego, CA). The International Knee Documentation Committee and Orthopädishe Arbeitsgruppe Knie scoring systems were used for clinical evaluation.

RESULTS

Stress radiographs showed that the mean side-to-side difference (posterior tibial translation compared with that of the contralateral knee) was reduced from 10.3 ± 2.4 mm preoperatively to 2.2 ± 1.5 mm at the last follow-up (P < .001), whereas the KT-1000 tests showed that this difference was reduced from 8.4 ± 2.2 mm preoperatively to 2.0 ± 1.4 mm (P < .001). The final International Knee Documentation Committee objective score was A in 30 patients (42.8%), B in 34 (48.6%), and C in 6 (8.6%). The mean Orthopädishe Arbeitsgruppe Knie score improved from 63.5 ± 10.4 to 88.9 ± 7.6 (P < .001).

CONCLUSIONS

Excellent posterior stability and relatively good clinical results were achieved with tensioning of the remnant PCL and AL bundle and PLC reconstruction by use of fibular tunnel for patients with chronic combined PCL-PLC injuries.

LEVEL OF EVIDENCE

Level IV, case series.

Anterolateral transtibial posterior cruciate ligament reconstruction combined with anatomical reconstruction of posterolateral corner insufficiency: comparison of single-bundle versus double-bundle posterior cruciate ligament reconstruction over a 2- to 6-year follow-up

BACKGROUND

There is a paucity of clinical studies comparing single- and double-bundle posterior cruciate ligament (PCL) reconstruction combined with a posterolateral corner reconstruction.

PURPOSE

To compare the clinical outcomes of single- and double-bundle transtibial PCL reconstruction combined with reconstruction of the lateral collateral ligament and popliteus tendon for posterolateral corner insufficiency.

STUDY DESIGN

Cohort study; Level of evidence 3.

METHODS

The study population consisted of 42 patients for whom a minimum of 2 years of follow-up data were available. The authors compared the clinical outcomes of 2 surgical techniques: a single-bundle technique (23 patients) and a double-bundle technique (19 patients), each combined with reconstruction of the lateral collateral ligament and popliteus tendon for posterolateral corner insufficiency.

RESULTS

There was no significant difference between the single- and double-bundle groups in mean side-to-side difference of posterior translation as measured with Telos stress radiography (4.2 ± 1.7 vs 3.9 ± 1.6 mm; P = .628). Rates of residual increased laxity greater than 5 mm were 22% in the single-bundle group and 21% in the double-bundle group. Regarding posterolateral rotatory instability, there were no differences between the 2 groups in mean side-to-side difference in the dial test (5.3° ± 2.7° vs 5.1° ± 2.4° at 30° of flexion [P = .800]; 6.7° ± 2.7° vs 6.7° ± 2.4° at 90° of flexion [P = .917]) or in varus stress radiography (1.2 ± 1.2 vs 1.3 ± 1.4 mm; P = .722). The Lysholm knee scores were 85.7 ± 7.6 in the single-bundle group and 87.7 ± 7.3 in the double-bundle group, and there was no significant difference between them (P = .392). There was also no difference between the groups in International Knee Documentation Committee knee score (P = .969); from this, the rates of abnormal and severely abnormal were 30% in the single-bundle group and 26% in the double-bundle group.

CONCLUSION

In this series, double-bundle PCL reconstruction combined with posterolateral corner reconstruction did not appear to have advantages over single-bundle PCL reconstruction combined with posterolateral corner reconstruction with respect to the clinical outcomes or posterior knee stability.

Functional outcome following PCL and complex knee ligament reconstruction

The purpose of this study was to evaluate the functional outcome of surgical reconstruction of the posterior cruciate ligament (PCL). In particular we wanted to document the recovery of knee muscle function. Twenty three patients underwent single bundle reconstruction of the PCL. There were four isolated PCL reconstructions. The remainder had PCL reconstructions combined with other ligament reconstructions. Patients were followed up at 2, 6, 12 and 26 weeks post operatively and underwent detailed functional assessment at 12 and 24 months. Outcome measures included the International Knee Documentation Committee (IKDC) score, the Tegner activity rating, and muscle dynamometry evaluating peak torque for knee flexion and extension. At final follow up 19 (83%) patients were rated as normal or nearly normal by the IKDC score. Seventeen (74%) patients returned to moderate or strenuous activity. Ligament stability was rated as normal or nearly normal in 20 (87%) patients. All 23 patients regained normal or nearly normal range of motion of the knee following surgery. Knee flexion peak torque demonstrated an average percentage deficit from the normal side of 24% at 12 months and 14% at 24 months. The deficits for extension were 35% and 9% for the same time points. PCL reconstruction is associated with a satisfactory clinical outcome but muscle function abnormalities may persist for 2 years.

Single-bundle posterior cruciate ligament reconstruction and mini-open popliteofibular ligament reconstruction in knees with severe posterior and posterolateral rotation instability: clinical results of minimum 2-year follow-up

PURPOSE

The aim of this study was to assess the clinical outcome of arthroscopy-assisted posterior cruciate ligament (PCL) reconstruction and mini-open popliteofibular ligament (PFL) reconstruction for severe posterior and posterolateral rotation instability of the knee with lateral collateral ligament intact.

METHODS

Arthroscopic PCL reconstruction and mini-open PFL reconstruction were performed consecutively in 24 patients with chronic posterior and posterolateral rotation instability of the knee. The inclusion criteria for surgery were a side-to-side difference in posterior translation of more than 12 mm measured with stress radiography and tibial external rotation of 10 degrees more than that of the contralateral uninjured knee without varus laxity. The exclusion criterion was combined anterior cruciate ligament injury. The patients underwent single-bundle PCL reconstruction with Achilles tendon allograft. A mini-open PFL reconstruction was performed with anterior tibialis allograft. A 2-cm incision was made on the lateral epicondyle to build the femoral tunnel, and a 3-cm incision was made near the fibular head for the fibular tunnel.

RESULTS

The minimum follow up was 2 years. At final follow up, 18 patients (75% [18 of 24]) were enrolled in the study group and 6 patients were lost. Postoperatively, mean posterior tibial translation (side-to-side difference) in our patients was reduced from 17.3 +/- 4.1 mm to 4.6 +/- 3.2 mm. Tibial external rotation was decreased from a mean of 14.7 degrees +/- 4.6 degrees to -2.8 degrees +/- 3.8 degrees, as compared with the contralateral uninjured knee. These differences were statistically significant. The International Knee Documentation Committee grade preoperatively was grade D in all 18 patients, whereas postoperatively, 5 were classified as grade A, 8 as grade B, and 5 as grade C.

CONCLUSIONS

In this small clinical series, single-bundle PCL reconstruction combined with mini-open PFL reconstruction was proven to correct pathologic excessive posterior and posterolateral rotation instability.

LEVEL OF EVIDENCE

Level IV, therapeutic case series (no control or historical group).

Single-bundle versus double-bundle posterior cruciate ligament reconstruction

PURPOSE

The purpose of this report is to present a systematic review of the literature to compare knee kinematics and clinical outcomes after single-bundle versus double-bundle posterior cruciate ligament reconstruction.

METHODS

Systematic review of the literature by PubMed search, reference review, and search of Arthroscopy identified the relevant biomechanical and clinical studies. The studies were critically evaluated to determine potential advantages of single-bundle or double-bundle reconstructions in anteroposterior stability, graft tension, rotational stability, and functional outcome.

RESULTS

Biomechanical comparisons evaluating anteroposterior stability described either no difference or increased stability with double-bundle reconstructions. Comparing these results is complicated by differential graft choices, tensioning techniques, and tunnel anatomy. Biomechanical studies of graft tension describe conflicting results regarding the optimal reconstruction technique. Recent studies of rotational stability suggest no advantage of double-bundle reconstruction in the setting of concomitant posterolateral corner repair but suggest a possible advantage in the setting of subtle posterolateral corner injury. Three retrospective clinical studies of single- and double-bundle reconstructions with methodologic limitations described no difference in clinical outcome.

CONCLUSIONS

The superiority of single-bundle or double-bundle posterior cruciate ligament reconstruction remains uncertain.

Popliteofibular ligament reconstruction for posterolateral external rotation instability of the knee

The aim of this study was to assess the clinical outcome of popliteofibular ligament (PFL) reconstruction for posterolateral external rotation instability of the knee. PFL reconstruction was performed consecutively in 22 patients with chronic external rotation instability of the knee. The inclusion criterion for surgery was tibial external rotation of 10 degrees more than the contralateral uninjured knee without varus laxity. A double bone tunnel was created at the PFL insertion of the fibular head through the lateral incision of the knee joint and a single bone tunnel at the popliteus tendon insertion on the femoral side. A semitendinosus autograft tendon or tibialis anterior allograft tendon was introduced through the fibular tunnel as a loop, then both free ends of the graft were introduced through the femoral tunnel and a bioabsorbable interference screw was used to fix the graft. The minimum follow-up was 2 years. Clinical review included the International Knee Documentation Committee (IKDC) scale and tibial external rotation assessment. All patients' preoperational tibial external rotation averaged 15 degrees more than the contralateral uninjured knee. operatively the tibial external rotation was decreased, average -3 degrees compared with the contralateral side. This difference was statistically significant. The final IKDC grades were: 22 cases with grade D preoperatively, and 6 were grade A, 8 were grade B, 7 were grade C and 1 was grade D postoperatively. In this small clinical series, PFL reconstruction technique was shown to correct pathological excessive tibial external rotation.