Introduction

Knees with chronic anterior cruciate ligament (ACL) tears often have degenerative changes. If these changes are severe, cartilage restorative procedures may be necessary in addition to ACL reconstruction (ACLR). The question in such cases is whether to perform the restorative procedures simultaneously with the ACLR. If they are not done simultaneously, the question becomes one of proper sequencing and the necessary time interval between procedures.

Individualization

Cases requiring combined procedures are inherently complicated. Some patients will need ACLR plus one other restorative procedure, but some patients may need a total of three or four such procedures. Decision-making can be helped by the application of certain principles, which will be discussed later. However, each patient’s individual characteristics should be carefully studied and weighed in decision-making. The patient’s pathology is most important, but work and life circumstances must be carefully considered to avoid disruption to the extent possible.

Surgeon Factors

The surgeon must also realistically weigh his or her own skill and experience. When in doubt, it is better to sequence procedures than to perform difficult procedures simultaneously with which the surgeon may have limited experience. Patients generally prefer simultaneity, but this should not be done if it will subject the patient to greater risk of failure.

Success Rates

In the literature and in our experience, success rates with appropriate combined procedures have been high. Table 63-1 summarizes the relevant literature. Surgery and aftercare must be meticulous. Reimbursement may not be commensurate with the amount of work performed. Not all surgeons will wish to perform these types of procedures. However, if the procedures are satisfactorily performed, and if the patients are carefully chosen, the results can be gratifying.

Table 63-1 Success Rates For Combined Procedures

ACI, Autologous chondrocyte implantation; ACLR, anterior cruciate ligament reconstruction; HSS, Hospital for Special Surgery; HTO, high-tibial osteotomy; IKDC, International Knee Documentation Committee; MAT, meniscal allograft transplantation; OATS, osteochondral autograft transfer system.

Patient Expectations

Patients must be counseled that success is by no means guaranteed with these combined procedures. It is important to discuss the possibility of failure and what the next steps would be. We believe that patients who do not comfortably accept the possibility of failure are best served by first seeing other surgeons to receive second opinions.

Restoration of Motion

The overriding concern in preoperative planning is the avoidance of loss of motion as a result of the surgical procedures. We will discuss the relative risk for each procedure in this regard. Above all, the knee must be flexible and noninflamed before surgery is performed. The reliability of the patient and access to appropriate physical therapy resources must also be factors in decision-making.

Anterior Cruciate Ligament Reconstruction and Microfracture

Microfracture has been shown to be an effective procedure for generating a fibrocartilaginous fill for full-thickness articular cartilage defects.^1–3 It can easily be performed together with ACLR and should be performed simultaneously whenever possible to save the patient an extra and unnecessary anesthetic. The 6-week postoperative period of touchdown weight bearing that is required after microfracture (MF) does not adversely affect the ACLR. It is important only to make sure that good passive range of motion (ROM) is achieved. Decreased activity after ACLR has actually been associated with less tunnel widening in one study.⁴ For those who believe in aggressive strengthening immediately after ACLR, this regimen will seem restrictive. However, in the long term there should be no adverse effect. We have not found the addition of ACLR to adversely affect the expected good results after microfractures. There is no 2-year follow-up literature on ACLR with microfracture of which we are aware. However, our clinical experience has been favorable with lesions less than 2 cm. We have found larger lesions to not fare as well and in earlier years had to revise several microfractures to autologous chondrocyte implantations (ACI). Although the ultimate results in those cases were good, in recent years we have proceeded directly to ACI when encountering lesions greater than 2 cm.

Anterior Cruciate Ligament Reconstruction and Autologous Chondrocyte Implantations

ACI^5–7 is the first procedure that has successfully generated hyaline-like cartilage in full-thickness articular cartilage defects. It is usually not carried out simultaneously with ACLR because the ACLR is usually performed before the need for ACI has been discovered. Thus the articular cartilage biopsy (ACB), rather than the ACI, is usually performed at the time of the ACLR. Generally the ACI will be performed as a staged subsequent procedure. If the lesion is on the femoral condyles, as opposed to the trochlea, we prefer to wait 4 to 6 months before performing ACI after ACLR. The reason is that ACI can involve hyperflexion of the knee to sew to the posterior aspect of many lesions. This hyperflexion will stress the graft, and we prefer not to subject newly implanted grafts to this stress. During the revascularization phase in the first few months postoperatively, grafts are severely weakened and are subject to plastic deformation if stressed. Trochlear grafts are implanted without hyperflexion and thus are safe early after ACLR. Allograft ACL grafts may need to be protected longer. If ACI and ACLR are performed simultaneously, the more restrictive ACI protocol needs to be adopted. This should not adversely affect the ACLR results. In general it is not advisable to perform ACI before ACLR because a stable knee is considered necessary for successful ACI. Also, this type of sequencing would require three procedures because the ACB needs to precede the ACI. However, in cases when the ACB has been performed prior to the ACLR, the ACI and ACLR may then be carried out simultaneously at a subsequent procedure. Good results have been reported after the combined procedures.⁸ Young patients with acute lesions, such as the 17-year-old girl shown in Fig. 63-1, are ideal candidates. Older patients with acute lesions can also obtain excellent results with ACLR and ACI, such as was the case with a 53-year-old woman who tore her ACL while snow skiing (Fig. 63-2). When the ACL tear is somewhat chronic even in a young patient, such as the 27-year-old woman with a failed ACLR performed at age 20 (Fig. 63-3), early degenerative changes can make treatment more difficult.

Fig. 63-1 This 3.5-cm² femoral condyle lesion occurred in a 17-year-old girl with a torn anterior cruciate ligament (ACL). She had hamstring ACL reconstruction with simultaneous articular cartilage biopsy, with autologous chondrocyte implantation (ACI) to follow as a staged procedure.

Fig. 63-2 53-year-old woman with acute anterior cruciate ligament (ACL) tear and large medial femoral condyle (MFC) lesion in an otherwise healthy knee.

Fig. 63-3 This 27-year-old woman, with a failed anterior cruciate ligament (ACL) reconstruction performed at age 20, already has significant degenerative articular cartilage disease.

Anterior Cruciate Ligament Reconstruction and Meniscal Allograft Implantation

Meniscal allograft implantation (MAT) has been associated with generally high success rates.^9–11 There is some risk in performing MAT simultaneously with ACLR because there is a propensity in some knees for stiffness after MAT. Crowding also occurs between the tibial tunnel for the ACLR and the trough for lateral MAT as well as the bone tunnel(s) for medial MAT. However, if these are the only two procedures necessary and if the surgeon has sufficient experience with both procedures, then it is possible to perform them simultaneously to save the patient the discomfort of a second procedure. The rehabilitation protocols are compatible, and avoidance of stiffness needs to be prioritized by using appropriately aggressive rehabilitation. If the ACLR is performed first, we prefer to wait 4 to 6 months before performing the MAT to allow the graft to mature as described in the section on ACLR and ACI. In theory, MAT should not performed before ACLR because a stable knee is a prerequisite for the performance of MAT. However, MAT followed within a few months by ACLR should not subject the graft to undue stress because the patient will not be vigorously active during this period. Indeed, if the procedures are staged it may be technically easier to perform the ACLR second because the MAT will be more easily performed in the knee with greater laxity before the ACLR.^12–17 The patient whose radiographs are shown in Fig. 63-4 had severe pain and was unable to perform his job as a federal law enforcement agent at 38 years of age, 16 years after ACL tear and meniscectomy. He underwent high-tibial osteotomy (HTO) with substantial improvement. ACLR was then performed with further improvement but with residual medial pain still persisting. MAT was then performed, leading to almost complete resolution of symptoms 1 year after surgery. These procedures allowed him to resume his career, including his 1-mile-run test, without pain.

Fig. 63-4 A and B, This 38-year-old federal law enforcement agent had chronic pain and was limited to primarily sedentary work after anterior cruciate ligament (ACL) tear and medial meniscectomy 16 years earlier. He had high-tibial osteotomy (HTO) and ACL reconstruction with marked improvement but still had limiting medial pain. He then underwent meniscal allograft implantation (MAT). One year later, he was pain free and able to perform his 1-mile run without pain.

Anterior Cruciate Ligament Reconstruction and Osteochondral Allograft or Osteochondral Autograft Transfer System

Osteochondral autograft transfer system (OATS)¹⁸ and osteochondral allograft (OCAI)¹⁹ are widely used procedures. Either can be performed simultaneously with ACLR if the surgeon has sufficient experience. They can also be performed sequentially before or after ACLR. The literature has shown good results.^20,21

Anterior Cruciate Ligament Reconstruction and High-Tibial Osteotomy

HTO has shown good results over many decades of use.^22,23 Numerous newer reports show good results after combined ACLR and HTO,^24–28 although the complication rate can be significant.²⁹ This combination also entails a potentially greater risk of stiffness relative to the other combined procedures. The reason is that all osteotomies, regardless of the surgical technique used, are somewhat unstable in the first few months postoperatively. Thus if the ACLR/HTO surgery does result in significant stiffness, it is harder to treat because aggressive mobilization of the knee cannot be performed in the first few months post-HTO due to the risk of displacing the osteotomy, even if rigid internal fixation is used. This is also somewhat dependent on the HTO technique used. Techniques performed above the tibial tubercle involve the periarticular structures. These HTO procedures add their own propensity to stiffness to that of the ACLR. Procedures performed below the tibial tubercle should involve less such risk. The surgeon must therefore assess the risks attendant to both the ACLR and HTO procedures as best as possible and decide whether there is excessive risk in performing both procedures simultaneously. We perform a bone transport osteotomy below the tubercle using an external fixator and no hardware, which has little risk of stiffness. Our hamstring ACLR procedure has also had excellent ROM results.³⁰ However, some ACLRs have required aggressive rehabilitation to regain full extension. Even though the number is small, it is difficult to predict with which knees this will occur. HTO patients often have some degree of medial arthrosis. These knees are also somewhat predisposed to stiffness.

Therefore, where possible, we prefer to perform the ACLR first, establish full ROM, and then perform the HTO on a staged basis as soon as full motion is obtained. If this staged schedule is too difficult for the patient, the HTO can be performed simultaneously with a full discussion of potential stiffness risk. Although the senior author has not had a permanent motion problem with the combined procedures, he nonetheless considers the staged procedure to be safer in these complicated knees.

We have found HTO to be an extremely reliable procedure for unicompartmental varus and have found the results of the combined procedure (simultaneously or staged) to be excellent. Initially we worried that ACLR in the presence of medial arthrosis might aggravate the arthrosis. However, we have never seen this occur and instead have found the ACLR to consistently result in clinical improvement in the symptoms of even moderate arthritis. We will perform ACLR/HTO in the presence of a moderate diminution in the medial joint space in a young patient. We will not, however, perform ACLR with HTO if bony deformity, subluxation, or severe loss of joint space is present. If all else is equal, greater aggressiveness is more justified in younger patients to avoid progression to joint replacement arthroplasty.

HTO is performed far less often in the United States than in Europe, apparently due to reasons of patient acceptance. However, with proper discussion patients are usually quite willing to undergo HTO. With the external fixator technique, patient acceptance is increased by the fact that alignment is precisely controlled on an outpatient basis, precluding excessive unattractive valgus. The use of only a small incision without retained hardware is also appealing. The presence of protruding pins is distasteful to some patients, but this is mitigated by the fact that the pins are only temporary. Other methods have their own advantages and disadvantages.

We perform HTO when mechanical axis radiographs (on standing hip-knee-ankle films) show four degrees or more of varus. It is important to point out that medial compartment cartilage restoration procedures generally have been shown to have a higher failure rate if HTO is not performed in the presence of significant varus. Thus although HTO is a procedure that many orthopaedic surgeons may not feel comfortable performing, it is important to perform where indicated.

HTO procedures are not without complications, and these patients must be operated on carefully and followed closely. Most, however, have a smooth course. Fig. 63-5 shows a patient 8 months after simultaneous ACLR and HTO. The osteotomy is well healed. The tibial fixation screw for the ACL graft can be seen proximal to the osteotomy. The medial joint space on these standing views shows increased cartilage space in the postoperative radiograph compared with preoperatively.

Fig. 63-5 Anterior cruciate ligament reconstruction with high-tibial osteotomy (ACLR/HTO). A, Preoperative view. B, Postoperative view.

Multiple Cartilage Restorative Procedures

Some patients require multiple procedures in addition to ACLR. The surgeon should separately consider the following five components of knee health: (1) articular cartilage, (2) menisci, (3) limb alignment, (4) bone deficiency, and (5) ACL deficiency. Thus a patient may need, for example, HTO for varus, MAT for symptomatic meniscal deficiency, ACI or MF for articular cartilage deficiency, and possibly a bone graft for osteochondritis desiccans. Staging becomes even more complicated in these cases. In general it is advisable to avoid combining more than two major procedures at once to avoid the risks of stiffness and infection. We have not had a deep infection in these combined cases, and an increased infection rate is not reflected in the literature.

Cartilage Preservation Versus Arthroplasty

Cartilage preservation is perhaps the most important reason to perform ACLR. In those cases in which articular cartilage damage has also occurred and the patient is symptomatic, restorative procedures may be necessary. If the surgeon performing the ACLR is not comfortable with these procedures, the patient may be referred to a surgeon either initially or after ACL reconstruction is completed. The references cited in this chapter indicate that success rates are high. Treatment of their pathology would seem to be preferable to advising patients that they should wait for further degeneration and have a joint replacement arthroplasty, as patients young enough to be ACLR candidates are generally too young to be good candidates for joint replacement. We wish to emphasize that, with some exceptions, only symptomatic patients should be treated. Asymptomatic varus is generally not a reason to perform HTO, nor is asymptomatic meniscal deficiency a reason to perform MAT. The exception to this rule may be articular cartilage deficiency in a younger patient. Even asymptomatic, full-thickness lesions in this population probably warrant treatment to prevent propagation. The sooner the patient’s cartilage deficiencies are treated, the better his or her outcome is likely to be.

Conclusions